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<journal-id journal-id-type="publisher-id">Front. Bioinform.</journal-id>
<journal-title>Frontiers in Bioinformatics</journal-title>
<abbrev-journal-title abbrev-type="pubmed">Front. Bioinform.</abbrev-journal-title>
<issn pub-type="epub">2673-7647</issn>
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<publisher-name>Frontiers Media S.A.</publisher-name>
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<article-id pub-id-type="publisher-id">1485797</article-id>
<article-id pub-id-type="doi">10.3389/fbinf.2025.1485797</article-id>
<article-categories>
<subj-group subj-group-type="heading">
<subject>Bioinformatics</subject>
<subj-group>
<subject>Brief Research Report</subject>
</subj-group>
</subj-group>
</article-categories>
<title-group>
<article-title>Improving acne severity detection: a GAN framework with contour accentuation for image deblurring</article-title>
<alt-title alt-title-type="left-running-head">Mascarenhas et al.</alt-title>
<alt-title alt-title-type="right-running-head">
<ext-link ext-link-type="uri" xlink:href="https://doi.org/10.3389/fbinf.2025.1485797">10.3389/fbinf.2025.1485797</ext-link>
</alt-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname>Mascarenhas</surname>
<given-names>Philomina Princiya</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<role content-type="https://credit.niso.org/contributor-roles/conceptualization/"/>
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</contrib>
<contrib contrib-type="author" corresp="yes">
<name>
<surname>Sannidhan</surname>
<given-names>M. S.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="corresp" rid="c001">&#x2a;</xref>
<uri xlink:href="https://loop.frontiersin.org/people/2213897/overview"/>
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<role content-type="https://credit.niso.org/contributor-roles/Writing - review &#x26; editing/"/>
</contrib>
<contrib contrib-type="author" corresp="yes">
<name>
<surname>Pinto</surname>
<given-names>Ancilla J.</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
<xref ref-type="corresp" rid="c001">&#x2a;</xref>
<uri xlink:href="https://loop.frontiersin.org/people/2825406/overview"/>
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<role content-type="https://credit.niso.org/contributor-roles/Writing - review &#x26; editing/"/>
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<contrib contrib-type="author">
<name>
<surname>Camero</surname>
<given-names>Dabis</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
<uri xlink:href="https://loop.frontiersin.org/people/2837402/overview"/>
<role content-type="https://credit.niso.org/contributor-roles/formal-analysis/"/>
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<contrib contrib-type="author">
<name>
<surname>Martis</surname>
<given-names>Jason Elroy</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
<uri xlink:href="https://loop.frontiersin.org/people/2753696/overview"/>
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<aff id="aff1">
<sup>1</sup>
<institution>Department of Computer Science and Engineering</institution>, <institution>NMAM Institute of Technology (Nitte Deemed to be University)</institution>, <addr-line>Nitte</addr-line>, <country>India</country>
</aff>
<aff id="aff2">
<sup>2</sup>
<institution>Department of Computer Science and Engineering</institution>, <institution>Manipal Institute of Technology</institution>, <institution>Manipal Academy of Higher Education</institution>, <addr-line>Manipal</addr-line>, <country>India</country>
</aff>
<aff id="aff3">
<sup>3</sup>
<institution>Department of Electrical Engineering</institution>, <institution>Penn State University Harrisburg</institution>, <addr-line>Middletown</addr-line>, <addr-line>PA</addr-line>, <country>United States</country>
</aff>
<aff id="aff4">
<sup>4</sup>
<institution>Department of Information Science and Engineering</institution>, <institution>NMAM Institute of Technology (Nitte Deemed to be University)</institution>, <addr-line>Nitte</addr-line>, <country>India</country>
</aff>
<author-notes>
<fn fn-type="edited-by">
<p>
<bold>Edited by:</bold> <ext-link ext-link-type="uri" xlink:href="https://loop.frontiersin.org/people/1155074/overview">Steven Fernandes</ext-link>, Creighton University, United States</p>
</fn>
<fn fn-type="edited-by">
<p>
<bold>Reviewed by:</bold> <ext-link ext-link-type="uri" xlink:href="https://loop.frontiersin.org/people/2340017/overview">Luigi Di Biasi</ext-link>, University of Salerno, Italy</p>
<p>
<ext-link ext-link-type="uri" xlink:href="https://loop.frontiersin.org/people/2779726/overview">Ramesh Nayak</ext-link>, Canara Engineering College, India</p>
</fn>
<corresp id="c001">&#x2a;Correspondence: M. S. Sannidhan, <email>sannidhan@nitte.edu.in</email>; Ancilla J. Pinto, <email>pinto.ancillaj@manipal.edu</email>
</corresp>
</author-notes>
<pub-date pub-type="epub">
<day>10</day>
<month>03</month>
<year>2025</year>
</pub-date>
<pub-date pub-type="collection">
<year>2025</year>
</pub-date>
<volume>5</volume>
<elocation-id>1485797</elocation-id>
<history>
<date date-type="received">
<day>24</day>
<month>08</month>
<year>2024</year>
</date>
<date date-type="accepted">
<day>14</day>
<month>02</month>
<year>2025</year>
</date>
</history>
<permissions>
<copyright-statement>Copyright &#xa9; 2025 Mascarenhas, Sannidhan, Pinto, Camero and Martis.</copyright-statement>
<copyright-year>2025</copyright-year>
<copyright-holder>Mascarenhas, Sannidhan, Pinto, Camero and Martis</copyright-holder>
<license xlink:href="http://creativecommons.org/licenses/by/4.0/">
<p>This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.</p>
</license>
</permissions>
<abstract>
<p>Teledermatology, a growing field of telemedicine, is widely used to diagnose skin conditions like acne, especially in young adults. Accurate diagnosis depends on clear images, but blurring is a common issue in most images. In particular, for acne images, it obscures acne spots and facial contours, leading to inaccurate diagnosis. Traditional methods to address blurring fail to recover fine details, making them unsuitable for teledermatology. To resolve this issue, the study proposes a framework based on generative networks. It comprises three main steps: the Contour Accentuation Technique, which outlines facial features to create a blurred sketch; a deblurring module, which enhances the sketch&#x2019;s clarity; and an image translator, which converts the refined sketch into a color photo that effectively highlights acne spots. Tested on Acne Recognition Dataset, the framework achieved an SSIM of 0.83, a PSNR of 22.35 dB, and an FID score of 10.77, demonstrating its ability to produce clear images for accurate acne diagnosis. Further, the details of research can be found on the project homepage at: <ext-link ext-link-type="uri" xlink:href="https://github.com/Princiya1990/CATDeblurring">https://github.com/Princiya1990/CATDeblurring</ext-link>.</p>
</abstract>
<kwd-group>
<kwd>generative adversarial networks</kwd>
<kwd>image deblurring</kwd>
<kwd>contour accentuation technique</kwd>
<kwd>teledermatology</kwd>
<kwd>acne severity detection</kwd>
</kwd-group>
<contract-sponsor id="cn001">Manipal Academy of Higher Education<named-content content-type="fundref-id">10.13039/100019305</named-content>
</contract-sponsor>
<custom-meta-wrap>
<custom-meta>
<meta-name>section-at-acceptance</meta-name>
<meta-value>Computational BioImaging</meta-value>
</custom-meta>
</custom-meta-wrap>
</article-meta>
</front>
<body>
<sec id="s1">
<title>1 Introduction</title>
<p>In digital image processing, clear images are essential for accurate analysis and decision-making in many areas (<xref ref-type="bibr" rid="B2">Bui et al., 2018</xref>). However, blurring caused by camera movement or focus problems can distort important details (<xref ref-type="bibr" rid="B24">Pan et al., 2019</xref>). This is especially problematic in teledermatology, where clear images are important for evaluating skin conditions, such as acne severity, to ensure accurate diagnoses, proper treatment, and avoid misunderstandings (<xref ref-type="bibr" rid="B33">Suha and Sanam, 2022</xref>). Considering this, there is a strong need for effective image processing methods to improve image clarity and retain fine details.</p>
<p>Straight forward approaches for deblurring, such as Wiener filtering and Richardson-Lucy deconvolution (<xref ref-type="bibr" rid="B32">&#x160;roubek et al., 2019</xref>), rely on mathematical models to reverse blurring by estimating and correcting the distortion, aiming to minimize the mean square error between the restored and original images (<xref ref-type="bibr" rid="B10">Gnanasambandam et al., 2024</xref>). However, these methods struggle with complex blurring or unpredictable noise, often resulting in issues like ringing artifacts and amplified noise (<xref ref-type="bibr" rid="B12">Joshi and Sheetlani, 2019</xref>). These limitations underscore the need for more adaptive and reliable approaches, with studies highlighting GAN-based deblurring techniques as a promising solution to overcome these challenges by restoring image clarity (<xref ref-type="bibr" rid="B19">Mankotia et al., 2024</xref>; <xref ref-type="bibr" rid="B31">Song and Lam, 2021</xref>). However, some studies also revealed that GANs suffer to generate better quality of deblurred images due to the insufficient exposure of facial structure hiding the contours in the blurred images (<xref ref-type="bibr" rid="B29">Shi et al., 2024</xref>; <xref ref-type="bibr" rid="B26">Qi et al., 2021</xref>; <xref ref-type="bibr" rid="B13">Jung et al., 2022</xref>). This limitation is particularly significant in applications like acne assessments, where facial contours provide major context for understanding lesion distribution and texture (<xref ref-type="bibr" rid="B27">Samizadeh, 2022</xref>). One commonly used technique to address this issue is translating the image into a sketch, which helps to sharpen the image by emphasizing its contours. However, when applied to blurred images, this approach often fails to produce clear sketches due to the insufficient visibility of facial structures (<xref ref-type="bibr" rid="B6">Chen et al., 2024</xref>). To address these challenges, implementing an image processing algorithm or preprocessor that exposes contours before sketching can significantly improve the clarity of sketches. This approach ensures better visualization and more accurate results, particularly in applications like dermatological assessments, where clear contour details are essential for understanding conditions like acne (<xref ref-type="bibr" rid="B9">Dumitrescu et al., 2021</xref>).</p>
<p>Building on the observations discussed earlier, the proposed image deblurring framework is designed to overcome the limitations of existing systems through three main components. The first is an image preprocessor called the Contour Accentuation Technique (CAT), which extracts the contours of facial structures from a blurred input image, presenting them in the form of a sketch. Next, a deblurring module featuring DeblurGAN refines the sketch produced by CAT, removing blur and enhancing clarity. Finally, an image translator module, powered by a conditional GAN (cGAN), converts the clear sketch into a color photo image. Although the CAT component initially generates a blurry sketch, it effectively highlights the facial contours, providing structural information that aids the deblurring module in producing a higher-quality sketch. These refined sketches, when translated into photo images by the image translator module, result in images where acne spots are clearly visible, improving their overall diagnostic utility. <xref ref-type="fig" rid="F1">Figure 1</xref> provides an overview of this process, showing the progression from deblurred input photo to clear photo image as output.</p>
<fig id="F1" position="float">
<label>FIGURE 1</label>
<caption>
<p>Sample image showing the workflow of the proposed image deblurring framework.</p>
</caption>
<graphic xlink:href="fbinf-05-1485797-g001.tif"/>
</fig>
<p>The effectiveness of the proposed image deblurring framework is evaluated using the Acne Recognition Dataset (<xref ref-type="bibr" rid="B14">Kucev, 2023</xref>) as the primary benchmark, specifically designed for acne severity detection. For further validation, standard datasets: CUHK (<xref ref-type="bibr" rid="B37">Wang and Tang, 2008</xref>), AR (<xref ref-type="bibr" rid="B3">Cao et al., 2022</xref>), and XM2GTS derived from a subset XM2VTS dataset (<xref ref-type="bibr" rid="B22">Messer et al., 1999</xref>) are used.</p>
<p>This research work has the following research contributions:<list list-type="simple">
<list-item>
<p>1. Implementation of CAT to reveal facial structures through sketch generation based on contour extraction.</p>
</list-item>
<list-item>
<p>2. Utilization of DeblurGAN to specifically enhance the clarity of blurred sketches generated by CAT in order to highlight acne spots.</p>
</list-item>
<list-item>
<p>3. Development of an image translator module using cGAN to transform sketches into color photo images, enabling a realistic visual analysis of acne spots.</p>
</list-item>
</list>
</p>
</sec>
<sec id="s2">
<title>2 Related works</title>
<p>
<xref ref-type="bibr" rid="B35">Vodrahalli et al. (2020)</xref> and <xref ref-type="bibr" rid="B24">Pan et al. (2019)</xref> emphasize that clear images are essential in teledermatology for accurate medical diagnoses. Meanwhile, <xref ref-type="bibr" rid="B33">Suha and Sanam (2022)</xref> point out that blurry images can easily cause misunderstandings when treating acne, leading to incorrect diagnoses. Straight forward methods such as Wiener filtering and Lucy-Richardson deconvolution (<xref ref-type="bibr" rid="B32">&#x160;roubek et al., 2019</xref>; <xref ref-type="bibr" rid="B12">Joshi and Sheetlani, 2019</xref>) work well only in stable conditions, as noted by <xref ref-type="bibr" rid="B10">Gnanasambandam et al. (2024)</xref>. Some works used GANs to fix blurry images because these methods can sharpen photos while keeping them looking natural (<xref ref-type="bibr" rid="B15">Kupyn et al., 2018</xref>; <xref ref-type="bibr" rid="B16">Kupyn et al., 2019</xref>; <xref ref-type="bibr" rid="B38">Xiong et al., 2024</xref>; <xref ref-type="bibr" rid="B25">Peng et al., 2023</xref>). Work by <xref ref-type="bibr" rid="B43">Zhai et al. (2022)</xref> and <xref ref-type="bibr" rid="B36">Wang et al. (2023)</xref> also showed that GANs are even capable of handling the challenge of deblurring facial images. However, keeping small facial details and highlighting contours continues to be a difficult task in face deblurring research (<xref ref-type="bibr" rid="B29">Shi et al., 2024</xref>; <xref ref-type="bibr" rid="B26">Qi et al., 2021</xref>). Also, works by <xref ref-type="bibr" rid="B17">Lee et al. (2020)</xref>, <xref ref-type="bibr" rid="B26">Qi et al. (2021)</xref>, and <xref ref-type="bibr" rid="B13">Jung et al. (2022)</xref> have shown that exposing contours remains a challenging task. Meanwhile, <xref ref-type="bibr" rid="B7">Collins et al. (2020)</xref> stressed the importance of minor facial feature information for producing the results of improved quality.</p>
<p>Recognizing the importance of clear images in teledermatology and the current challenges in GAN-based facial deblurring, this study focuses on improving these methods for acne imaging through contour accentuation and sketch-based transformations. <xref ref-type="bibr" rid="B21">Martis et al. (2024)</xref> and <xref ref-type="bibr" rid="B4">Capozzi et al. (2021)</xref> proved that clearly highlighting facial boundaries in training sketches can improve the quality of images produced by sketch-to-photo GANs. Likewise, <xref ref-type="bibr" rid="B19">Mankotia et al. (2024)</xref> reported that DeblurGAN performs better when the facial outline is clearly exposed. Building on these findings, <xref ref-type="bibr" rid="B5">Chen et al. (2023)</xref> demonstrated that using a preprocessor to expose contours early in the process leads to better deblurring performance. Motivated by this, we incorporated CAT as a preprocessor in this work to achieve better deblurring performance.</p>
</sec>
<sec id="s3">
<title>3 Proposed system</title>
<p>The proposed image deblurring framework consists of three primary components:1) Contour Accentuation Technique (CAT), 2) Deblurring Module, 3) Image Translator module. <xref ref-type="fig" rid="F2">Figure 2</xref> shows the entire workflow of our system and details of each process are elaborated in subsequent sections.</p>
<fig id="F2" position="float">
<label>FIGURE 2</label>
<caption>
<p>Overview of the proposed image deblurring framework with CAT.</p>
</caption>
<graphic xlink:href="fbinf-05-1485797-g002.tif"/>
</fig>
<sec id="s3-1">
<title>3.1 Contour accentuation technique</title>
<p>This is a preprocessor used to transform the image into a sketch where important features, such as contours, are exposed in blurred image aiding to improve the quality of the image generation further. <xref ref-type="fig" rid="F3">Figure 3</xref> outlines the steps of CAT, including grayscale, blending, and contrast correction. These steps work together to refine the image, exposing the contours. Each step is discussed in detail in the following subsections.</p>
<fig id="F3" position="float">
<label>FIGURE 3</label>
<caption>
<p>Illustration of proposed CAT process.</p>
</caption>
<graphic xlink:href="fbinf-05-1485797-g003.tif"/>
</fig>
<sec id="s3-1-1">
<title>3.1.1 Grayscale conversion</title>
<p>This step transforms the color image into a grayscale version. This method reduces color information targeting on exposing the facial boundary to reveal the face structure. This step is vital for sketch generation, as it exposes the structural features necessary for creating realistic sketches (<xref ref-type="bibr" rid="B34">Tani and Yamawaki, 2024</xref>). <xref ref-type="disp-formula" rid="e1">Equation 1</xref> reveals the mathematical formulation for the grayscale conversion.<disp-formula id="e1">
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<mml:mo>&#x2b;</mml:mo>
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<label>(1)</label>
</disp-formula>
</p>
<p>In the equation, <inline-formula id="inf1">
<mml:math id="m2">
<mml:mrow>
<mml:mi>R</mml:mi>
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<mml:mfenced open="(" close=")" separators="|">
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</inline-formula> denote the red, green, and blue components of a pixel. The specific values 0.299, 0.587, and 0.114 correspond to the weighting factors used to convert a color image to grayscale in the RGB color space. These values are based on the relative luminance contributions of the red, green, and blue components, respectively, as defined by the ITU-R BT.601 standard. The green component contributes the most to perceived brightness by human eye, which is why it has the highest weighting.</p>
</sec>
<sec id="s3-1-2">
<title>3.1.2 Blending function</title>
<p>In this process, the transitions between light and dark areas in grayscale image is smoothened in order to preserve key details in the facial area (<xref ref-type="bibr" rid="B41">Zhang et al., 2020</xref>). <xref ref-type="disp-formula" rid="e2">Equation 2</xref> explains the blending function used in CAT.<disp-formula id="e2">
<mml:math id="m3">
<mml:mrow>
<mml:mi mathvariant="bold-italic">B</mml:mi>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:mi mathvariant="bold-italic">x</mml:mi>
<mml:mo>,</mml:mo>
<mml:mi mathvariant="bold-italic">y</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
<mml:mo>&#x3d;</mml:mo>
<mml:mi mathvariant="bold-italic">G</mml:mi>
<mml:mi mathvariant="bold-italic">r</mml:mi>
<mml:mi mathvariant="bold-italic">a</mml:mi>
<mml:mi mathvariant="bold-italic">y</mml:mi>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:mi mathvariant="bold-italic">x</mml:mi>
<mml:mo>,</mml:mo>
<mml:mi mathvariant="bold-italic">y</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
<mml:mtext>&#x2009;</mml:mtext>
<mml:mo>&#x2a;</mml:mo>
<mml:mi mathvariant="bold-italic">K</mml:mi>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:mi mathvariant="bold-italic">x</mml:mi>
<mml:mo>,</mml:mo>
<mml:mi mathvariant="bold-italic">y</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:math>
<label>(2)</label>
</disp-formula>
</p>
<p>In this equation, <inline-formula id="inf2">
<mml:math id="m4">
<mml:mrow>
<mml:mi>B</mml:mi>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:mi>x</mml:mi>
<mml:mo>,</mml:mo>
<mml:mi>y</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:math>
</inline-formula> represents the blended image obtained after applying the Gaussian kernel to the original image <inline-formula id="inf3">
<mml:math id="m5">
<mml:mrow>
<mml:mi>I</mml:mi>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:mi>x</mml:mi>
<mml:mo>,</mml:mo>
<mml:mi>y</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:math>
</inline-formula> through a convolution process. This operation overlaps the kernel on each pixel of the image and computes a weighted average of the surrounding pixels, with weights given by the kernel as per <xref ref-type="disp-formula" rid="e3">Equation 3</xref>.<disp-formula id="e3">
<mml:math id="m6">
<mml:mrow>
<mml:mi mathvariant="bold-italic">K</mml:mi>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:mi mathvariant="bold-italic">x</mml:mi>
<mml:mo>,</mml:mo>
<mml:mi mathvariant="bold-italic">y</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
<mml:mo>&#x3d;</mml:mo>
<mml:mfrac>
<mml:mn mathvariant="bold">1</mml:mn>
<mml:mrow>
<mml:mn mathvariant="bold">2</mml:mn>
<mml:mi mathvariant="bold-italic">&#x3c0;</mml:mi>
<mml:msup>
<mml:mi mathvariant="bold-italic">&#x3c3;</mml:mi>
<mml:mn mathvariant="bold">2</mml:mn>
</mml:msup>
</mml:mrow>
</mml:mfrac>
<mml:mo>&#xd7;</mml:mo>
<mml:msup>
<mml:mi mathvariant="bold-italic">e</mml:mi>
<mml:mrow>
<mml:mo>&#x2212;</mml:mo>
<mml:mfrac>
<mml:mrow>
<mml:msup>
<mml:mi mathvariant="bold-italic">x</mml:mi>
<mml:mn mathvariant="bold">2</mml:mn>
</mml:msup>
<mml:mo>&#x2b;</mml:mo>
<mml:msup>
<mml:mi mathvariant="bold-italic">y</mml:mi>
<mml:mn mathvariant="bold">2</mml:mn>
</mml:msup>
</mml:mrow>
<mml:mrow>
<mml:mn mathvariant="bold">2</mml:mn>
<mml:msup>
<mml:mi mathvariant="bold-italic">&#x3c3;</mml:mi>
<mml:mn mathvariant="bold">2</mml:mn>
</mml:msup>
</mml:mrow>
</mml:mfrac>
</mml:mrow>
</mml:msup>
</mml:mrow>
</mml:math>
<label>(3)</label>
</disp-formula>
</p>
<p>The parameter <inline-formula id="inf4">
<mml:math id="m7">
<mml:mrow>
<mml:msup>
<mml:mi>&#x3c3;</mml:mi>
<mml:mn>2</mml:mn>
</mml:msup>
</mml:mrow>
</mml:math>
</inline-formula> is adjusted to achieve effects, such as enhancing the contrast, sharpening the edges, or smoothing the noise.</p>
</sec>
<sec id="s3-1-3">
<title>3.1.3 Contrast correction</title>
<p>At this stage, blended image is enhanced by adjusting brightness and tuning luminance. For dark images, a luminance value greater than 1 is used, and for light images, less than 1, ensuring realistic and consistent luminance (<xref ref-type="bibr" rid="B42">Chen and Chen, 2022</xref>). Additionally, the function adjusts contrast, essential for blending images with different exposures or color temperatures (<xref ref-type="bibr" rid="B8">Dang et al., 2024</xref>). <xref ref-type="disp-formula" rid="e4">Equation 4</xref> demonstrates this process mathematically.<disp-formula id="e4">
<mml:math id="m8">
<mml:mrow>
<mml:msub>
<mml:mi mathvariant="bold-italic">V</mml:mi>
<mml:mrow>
<mml:mi mathvariant="bold-italic">o</mml:mi>
<mml:mi mathvariant="bold-italic">u</mml:mi>
<mml:mi mathvariant="bold-italic">t</mml:mi>
</mml:mrow>
</mml:msub>
<mml:mo>&#x3d;</mml:mo>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:msup>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:mfrac>
<mml:mrow>
<mml:msub>
<mml:mi mathvariant="bold-italic">V</mml:mi>
<mml:mrow>
<mml:mi mathvariant="bold-italic">i</mml:mi>
<mml:mi mathvariant="bold-italic">n</mml:mi>
</mml:mrow>
</mml:msub>
</mml:mrow>
<mml:mrow>
<mml:mn mathvariant="bold">255</mml:mn>
</mml:mrow>
</mml:mfrac>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
<mml:msup>
<mml:mi mathvariant="bold-italic">&#x3b3;</mml:mi>
<mml:mrow>
<mml:mo>&#x2212;</mml:mo>
<mml:mn mathvariant="bold">1</mml:mn>
</mml:mrow>
</mml:msup>
</mml:msup>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
<mml:mo>&#xd7;</mml:mo>
<mml:mn mathvariant="bold">255</mml:mn>
</mml:mrow>
</mml:math>
<label>(4)</label>
</disp-formula>
</p>
<p>This equation shows how each pixel <inline-formula id="inf5">
<mml:math id="m9">
<mml:mrow>
<mml:msub>
<mml:mi>V</mml:mi>
<mml:mrow>
<mml:mi>i</mml:mi>
<mml:mi>n</mml:mi>
</mml:mrow>
</mml:msub>
</mml:mrow>
</mml:math>
</inline-formula> in the blended image is adjusted to produce the output pixel <inline-formula id="inf6">
<mml:math id="m10">
<mml:mrow>
<mml:msub>
<mml:mi>V</mml:mi>
<mml:mrow>
<mml:mi>o</mml:mi>
<mml:mi>u</mml:mi>
<mml:mi>t</mml:mi>
</mml:mrow>
</mml:msub>
</mml:mrow>
</mml:math>
</inline-formula> after applying the gamma correction. <inline-formula id="inf7">
<mml:math id="m11">
<mml:mrow>
<mml:msup>
<mml:mi>&#x3b3;</mml:mi>
<mml:mrow>
<mml:mo>&#x2212;</mml:mo>
<mml:mn>1</mml:mn>
</mml:mrow>
</mml:msup>
</mml:mrow>
</mml:math>
</inline-formula> is the inverse of the gamma value, used to lower the original luminance to balance luminance level. The number <inline-formula id="inf8">
<mml:math id="m12">
<mml:mrow>
<mml:mn>255</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> is used to normalize and denormalize pixel values. Since the system deals with 8-bit gray scale images where pixel values range from 0 to 255, this normalization (divided by 255) scales the pixel values to a range of <inline-formula id="inf9">
<mml:math id="m13">
<mml:mrow>
<mml:mn>0</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> to <inline-formula id="inf10">
<mml:math id="m14">
<mml:mrow>
<mml:mn>1</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula>, which is necessary for the gamma correction calculation. After the calculation, the pixel values are scaled back (multiplied by 255) to the original range of 0&#x2013;255.</p>
</sec>
</sec>
<sec id="s3-2">
<title>3.2 Deblurring module</title>
<p>The deblurring module takes blurred sketches produced by the CAT as input and outputs deblurred sketches. As shown in <xref ref-type="fig" rid="F2">Figure 2</xref>, this module uses DeblurGAN (<xref ref-type="bibr" rid="B15">Kupyn et al., 2018</xref>), trained specifically on facial sketches, to achieve the deblurring process. DeblurGAN enhances blurred sketches by training GAN network that contains generator and discriminator components. The generator consists of a deep convolutional neural network that performs an end-to-end transformation from blurred to deblurred facial sketches. It starts with an initial convolutional layer with 64 filters, a <inline-formula id="inf11">
<mml:math id="m15">
<mml:mrow>
<mml:mn>3</mml:mn>
<mml:mo>&#xd7;</mml:mo>
<mml:mn>3</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> kernel size with a step size of one to extract low-level features of the blurred facial sketch, followed by two down-sampling layers with <inline-formula id="inf12">
<mml:math id="m16">
<mml:mrow>
<mml:mn>128</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> and <inline-formula id="inf13">
<mml:math id="m17">
<mml:mrow>
<mml:mn>256</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> filters each using a kernel of <inline-formula id="inf14">
<mml:math id="m18">
<mml:mrow>
<mml:mn>3</mml:mn>
<mml:mo>&#xd7;</mml:mo>
<mml:mn>3</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> with a step size of 2 to capture its abstract representations. There are nine residual blocks, each filtering <inline-formula id="inf15">
<mml:math id="m19">
<mml:mrow>
<mml:mn>3</mml:mn>
<mml:mo>&#xd7;</mml:mo>
<mml:mn>3</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> convolutional layers and skip connections to prevent vanishing gradient problems, facilitating deeper network training. There are two up-sampling layers with <inline-formula id="inf16">
<mml:math id="m20">
<mml:mrow>
<mml:mn>128</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> and <inline-formula id="inf17">
<mml:math id="m21">
<mml:mrow>
<mml:mn>64</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> transposed convolution filters for reconstructing the deblurred facial sketch by refining details and reducing the noise factor. Finally, the output layer employs a <inline-formula id="inf18">
<mml:math id="m22">
<mml:mrow>
<mml:mn>7</mml:mn>
<mml:mo>&#xd7;</mml:mo>
<mml:mn>7</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> convolutional layer with a Tanh activation function used to normalize the pixel between &#x2212;1 and 1.</p>
<p>The discriminator module distinguishes between original and synthetic sketches. It employs four convolutional layers with filters 64, 128, 256 and 512 respectively, each using 4 &#xd7; 4 kernel with step size of 2 (except for the last layer). To enhance training stability and feature extraction, LeakyReLU activation with <inline-formula id="inf19">
<mml:math id="m23">
<mml:mrow>
<mml:mi>&#x3b1;</mml:mi>
<mml:mo>&#x3d;</mml:mo>
<mml:mn>0.2</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> is utilized. Additionally, batch normalization with momentum value of 0.999 is applied to all layers except the first to further stabilize training. Batch normalization is applied in all layers except the first. The last layer comprises a fully connected layer with one neuron that produces a scalar output to compute the loss that reveals the similarity of clear sketch in correspondence to the original and synthetic sketch. To improve the training process of the model, Wasserstein distance is used (<xref ref-type="bibr" rid="B31">Song and Lam, 2021</xref>). <xref ref-type="disp-formula" rid="e5">Equation 5</xref> describes the mathematical formulation of Wasserstein distance.<disp-formula id="e5">
<mml:math id="m24">
<mml:mrow>
<mml:msub>
<mml:mi mathvariant="bold-italic">W</mml:mi>
<mml:mrow>
<mml:mi mathvariant="bold-italic">l</mml:mi>
<mml:mi mathvariant="bold-italic">o</mml:mi>
<mml:mi mathvariant="bold-italic">s</mml:mi>
<mml:mi mathvariant="bold-italic">s</mml:mi>
</mml:mrow>
</mml:msub>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:msub>
<mml:mi mathvariant="bold-italic">P</mml:mi>
<mml:mi mathvariant="bold-italic">r</mml:mi>
</mml:msub>
<mml:mo>,</mml:mo>
<mml:msub>
<mml:mi mathvariant="bold-italic">P</mml:mi>
<mml:mi mathvariant="bold-italic">g</mml:mi>
</mml:msub>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
<mml:mo>&#x3d;</mml:mo>
<mml:msub>
<mml:mi mathvariant="bold-italic">inf</mml:mi>
<mml:mrow>
<mml:mi mathvariant="bold-italic">&#x3b3;</mml:mi>
<mml:mi mathvariant="bold-italic">&#x3f5;</mml:mi>
<mml:mi mathvariant="bold-italic">&#x3c0;</mml:mi>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:msub>
<mml:mi mathvariant="bold-italic">P</mml:mi>
<mml:mi mathvariant="bold-italic">r</mml:mi>
</mml:msub>
<mml:mo>,</mml:mo>
<mml:msub>
<mml:mi mathvariant="bold-italic">P</mml:mi>
<mml:mi mathvariant="bold-italic">g</mml:mi>
</mml:msub>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:msub>
<mml:mo>&#x2061;</mml:mo>
<mml:msub>
<mml:mi mathvariant="bold-italic">E</mml:mi>
<mml:mrow>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:mi mathvariant="bold-italic">x</mml:mi>
<mml:mo>,</mml:mo>
<mml:mi mathvariant="bold-italic">y</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
<mml:mo>&#x223c;</mml:mo>
<mml:mi mathvariant="bold-italic">&#x3b3;</mml:mi>
</mml:mrow>
</mml:msub>
<mml:mrow>
<mml:mfenced open="[" close="]" separators="|">
<mml:mrow>
<mml:mfenced open="&#x2016;" close="&#x2016;" separators="|">
<mml:mrow>
<mml:mi mathvariant="bold-italic">x</mml:mi>
<mml:mo>&#x2212;</mml:mo>
<mml:mi mathvariant="bold-italic">y</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:math>
<label>(5)</label>
</disp-formula>
</p>
<p>In <xref ref-type="disp-formula" rid="e5">Equation 5</xref>, <inline-formula id="inf20">
<mml:math id="m25">
<mml:mrow>
<mml:msub>
<mml:mi>P</mml:mi>
<mml:mi>r</mml:mi>
</mml:msub>
</mml:mrow>
</mml:math>
</inline-formula> and <inline-formula id="inf21">
<mml:math id="m26">
<mml:mrow>
<mml:msub>
<mml:mi>P</mml:mi>
<mml:mi>g</mml:mi>
</mml:msub>
</mml:mrow>
</mml:math>
</inline-formula>&#x200b; represent the original and synthetic probability of pixel intensity distribution of the sketches, respectively, while <inline-formula id="inf22">
<mml:math id="m27">
<mml:mrow>
<mml:mi>&#x3c0;</mml:mi>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:msub>
<mml:mi>P</mml:mi>
<mml:mi>r</mml:mi>
</mml:msub>
<mml:mo>,</mml:mo>
<mml:msub>
<mml:mi>P</mml:mi>
<mml:mi>g</mml:mi>
</mml:msub>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:math>
</inline-formula> denotes the set of all joint distributions &#x3b3; whose marginals are <inline-formula id="inf23">
<mml:math id="m28">
<mml:mrow>
<mml:msub>
<mml:mi>P</mml:mi>
<mml:mi>r</mml:mi>
</mml:msub>
</mml:mrow>
</mml:math>
</inline-formula> and <inline-formula id="inf24">
<mml:math id="m29">
<mml:mrow>
<mml:msub>
<mml:mi>P</mml:mi>
<mml:mi>g</mml:mi>
</mml:msub>
</mml:mrow>
</mml:math>
</inline-formula>. Additionally, we use the learning rates of 0.0002 for the discriminator with hyperparameters of <inline-formula id="inf25">
<mml:math id="m30">
<mml:mrow>
<mml:msub>
<mml:mi>&#x3b2;</mml:mi>
<mml:mn>1</mml:mn>
</mml:msub>
<mml:mo>&#x3d;</mml:mo>
<mml:mn>0.5</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> and <inline-formula id="inf26">
<mml:math id="m31">
<mml:mrow>
<mml:msub>
<mml:mi>&#x3b2;</mml:mi>
<mml:mn>2</mml:mn>
</mml:msub>
<mml:mo>&#x3d;</mml:mo>
<mml:mn>0.999</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> respectively.</p>
</sec>
<sec id="s3-3">
<title>3.3 Image translator module</title>
<p>The generated sketch from the deblurring module is fed as input to this module. As depicted in <xref ref-type="fig" rid="F2">Figure 2</xref>, thus module uses sketch-to-photo cGAN. Unlike the deblurring module, this module focuses on generating photo-realistic images preserving the structure obtained from the deblurring module. The generator architecture in this case begins with an initial convolutional layer of 64 filters with <inline-formula id="inf27">
<mml:math id="m32">
<mml:mrow>
<mml:mn>4</mml:mn>
<mml:mo>&#xd7;</mml:mo>
<mml:mn>4</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> kernel and a step size of two, followed by down sampling layers with 128, 256 and 512 filters using a <inline-formula id="inf28">
<mml:math id="m33">
<mml:mrow>
<mml:mn>4</mml:mn>
<mml:mo>&#xd7;</mml:mo>
<mml:mn>4</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> kernel and a step size of two, followed by nine residual blocks featuring <inline-formula id="inf29">
<mml:math id="m34">
<mml:mrow>
<mml:mn>3</mml:mn>
<mml:mo>&#xd7;</mml:mo>
<mml:mn>3</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> convolutions and skip connections. The up-sampling layer uses 512, 256, 128 and 64 transposed convolutional filters. Finally, the output layer produces RGB images with a <inline-formula id="inf30">
<mml:math id="m35">
<mml:mrow>
<mml:mn>4</mml:mn>
<mml:mo>&#xd7;</mml:mo>
<mml:mn>4</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> kernel with a step size of 1 and Tanh activation function that translates a sketch into a photo-realistic image (<xref ref-type="bibr" rid="B28">Sannidhan et al., 2019</xref>).</p>
<p>The discriminator employs a patch-based structure with four convolutional layers with filters 64,128, 256 and 512 respectively using a <inline-formula id="inf31">
<mml:math id="m36">
<mml:mrow>
<mml:mn>4</mml:mn>
<mml:mo>&#xd7;</mml:mo>
<mml:mn>4</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> kernel with LeakyReLU activation with <inline-formula id="inf32">
<mml:math id="m37">
<mml:mrow>
<mml:mi>&#x3b1;</mml:mi>
<mml:mo>&#x3d;</mml:mo>
<mml:mn>0.2</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> and batch normalization with momentum value of 0.999. The last layer produces a scalar output that evaluates adversarial loss. The loss function evaluates the similarity index of the generated photo images against original photos through adversarial and Structural Similarity Index (SSI) values (<xref ref-type="bibr" rid="B23">Osahor et al., 2020</xref>; <xref ref-type="bibr" rid="B40">Yu et al., 2019</xref>). <xref ref-type="disp-formula" rid="e6">Equation 6</xref> explains the loss function important for evaluating the similarity between original and generated images.<disp-formula id="e6">
<mml:math id="m38">
<mml:mrow>
<mml:msub>
<mml:mi>L</mml:mi>
<mml:mrow>
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</mml:mrow>
</mml:msub>
<mml:mo>&#x3d;</mml:mo>
<mml:msub>
<mml:mi>&#x3bb;</mml:mi>
<mml:mrow>
<mml:mi>a</mml:mi>
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</mml:msub>
<mml:msub>
<mml:mi>L</mml:mi>
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<mml:mi>a</mml:mi>
<mml:mi>d</mml:mi>
<mml:mi>v</mml:mi>
</mml:mrow>
</mml:msub>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:mi>G</mml:mi>
<mml:mo>,</mml:mo>
<mml:mi>D</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
<mml:mo>&#x2b;</mml:mo>
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</mml:msub>
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<mml:mi>L</mml:mi>
<mml:mrow>
<mml:mi>s</mml:mi>
<mml:mi>s</mml:mi>
<mml:mi>i</mml:mi>
</mml:mrow>
</mml:msub>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:mi>G</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:math>
<label>(6)</label>
</disp-formula>
</p>
<p>In the equation, <inline-formula id="inf33">
<mml:math id="m39">
<mml:mrow>
<mml:msub>
<mml:mi>L</mml:mi>
<mml:mrow>
<mml:mi>t</mml:mi>
<mml:mi>o</mml:mi>
<mml:mi>t</mml:mi>
<mml:mi>a</mml:mi>
<mml:mi>l</mml:mi>
</mml:mrow>
</mml:msub>
</mml:mrow>
</mml:math>
</inline-formula> is the total loss function to be minimized by the discriminator. <inline-formula id="inf34">
<mml:math id="m40">
<mml:mrow>
<mml:msub>
<mml:mi>L</mml:mi>
<mml:mrow>
<mml:mi>a</mml:mi>
<mml:mi>d</mml:mi>
<mml:mi>v</mml:mi>
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<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:mi>G</mml:mi>
<mml:mo>,</mml:mo>
<mml:mi>D</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:math>
</inline-formula> represents the traditional adversarial loss function between the generator <inline-formula id="inf35">
<mml:math id="m41">
<mml:mrow>
<mml:mi>G</mml:mi>
</mml:mrow>
</mml:math>
</inline-formula> and discriminator <inline-formula id="inf36">
<mml:math id="m42">
<mml:mrow>
<mml:mi>D</mml:mi>
</mml:mrow>
</mml:math>
</inline-formula>. <inline-formula id="inf37">
<mml:math id="m43">
<mml:mrow>
<mml:msub>
<mml:mi>L</mml:mi>
<mml:mrow>
<mml:mi>s</mml:mi>
<mml:mi>s</mml:mi>
<mml:mi>i</mml:mi>
</mml:mrow>
</mml:msub>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:mi>G</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:math>
</inline-formula> is the loss derived from the Structural Similarity Index (SSI), measuring the similarity between the synthetic images by <inline-formula id="inf38">
<mml:math id="m44">
<mml:mrow>
<mml:mi>G</mml:mi>
</mml:mrow>
</mml:math>
</inline-formula> and the target original images. <inline-formula id="inf39">
<mml:math id="m45">
<mml:mrow>
<mml:msub>
<mml:mi>&#x3bb;</mml:mi>
<mml:mrow>
<mml:mi>a</mml:mi>
<mml:mi>d</mml:mi>
<mml:mi>v</mml:mi>
</mml:mrow>
</mml:msub>
</mml:mrow>
</mml:math>
</inline-formula> and <inline-formula id="inf40">
<mml:math id="m46">
<mml:mrow>
<mml:msub>
<mml:mi>&#x3bb;</mml:mi>
<mml:mrow>
<mml:mi>s</mml:mi>
<mml:mi>s</mml:mi>
<mml:mi>i</mml:mi>
</mml:mrow>
</mml:msub>
</mml:mrow>
</mml:math>
</inline-formula> are weighting coefficients that balance the contribution of adversarial loss and SSI-based similarity loss, respectively. The values chosen for <inline-formula id="inf41">
<mml:math id="m47">
<mml:mrow>
<mml:msub>
<mml:mi>&#x3bb;</mml:mi>
<mml:mrow>
<mml:mi>a</mml:mi>
<mml:mi>d</mml:mi>
<mml:mi>v</mml:mi>
</mml:mrow>
</mml:msub>
<mml:mo>&#x3d;</mml:mo>
<mml:mn>0.8</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> and <inline-formula id="inf42">
<mml:math id="m48">
<mml:mrow>
<mml:msub>
<mml:mi>&#x3bb;</mml:mi>
<mml:mrow>
<mml:mi>s</mml:mi>
<mml:mi>s</mml:mi>
<mml:mi>i</mml:mi>
</mml:mrow>
</mml:msub>
<mml:mo>&#x3d;</mml:mo>
<mml:mn>0.2</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> with hyperparameters of <inline-formula id="inf43">
<mml:math id="m49">
<mml:mrow>
<mml:msub>
<mml:mi>&#x3b2;</mml:mi>
<mml:mn>1</mml:mn>
</mml:msub>
<mml:mo>&#x3d;</mml:mo>
<mml:mn>0.5</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> and <inline-formula id="inf44">
<mml:math id="m50">
<mml:mrow>
<mml:msub>
<mml:mi>&#x3b2;</mml:mi>
<mml:mn>2</mml:mn>
</mml:msub>
<mml:mo>&#x3d;</mml:mo>
<mml:mn>0.999</mml:mn>
</mml:mrow>
</mml:math>
</inline-formula> respectively.</p>
</sec>
</sec>
<sec id="s4">
<title>4 Design of the proposed image deblurring framework</title>
<p>This section presents <xref ref-type="statement" rid="Algorithm_1">Algorithm 1</xref>: Deblurred_Sketch_To_Photo, which details an approach for converting blurred sketches into clear, color photos using GANs integrated with CAT.</p>
<p>
<statement content-type="algorithm" id="Algorithm_1">
<label>Algorithm 1</label>
<p>Deblurred_Sketch_To_Photo.<list list-type="simple">
<list-item>
<p>
<bold>Input:</bold> Blurred sketch.</p>
</list-item>
<list-item>
<p>
<bold>Output:</bold> Color Photo with improved clarity.</p>
</list-item>
<list-item>
<p>1:&#x2003;Initialize DeblurGAN with generator <inline-formula id="inf45">
<mml:math id="m51">
<mml:mrow>
<mml:mi>G</mml:mi>
</mml:mrow>
</mml:math>
</inline-formula>&#x2003;&#x2003;&#x2003;and discriminator <inline-formula id="inf46">
<mml:math id="m52">
<mml:mrow>
<mml:mi>D</mml:mi>
</mml:mrow>
</mml:math>
</inline-formula>
</p>
</list-item>
<list-item>
<p>2:&#x2003;<bold>For every blurred image do</bold>
</p>
</list-item>
<list-item>
<p>3:&#x2003;<inline-formula id="inf47">
<mml:math id="m53">
<mml:mrow>
<mml:msub>
<mml:mi>I</mml:mi>
<mml:mrow>
<mml:mi>b</mml:mi>
<mml:mi>l</mml:mi>
<mml:mi>u</mml:mi>
<mml:mi>r</mml:mi>
<mml:mi>r</mml:mi>
<mml:mi>e</mml:mi>
<mml:mi>d</mml:mi>
</mml:mrow>
</mml:msub>
<mml:mo>&#x2190;</mml:mo>
<mml:mi>C</mml:mi>
<mml:mi>A</mml:mi>
<mml:mi>T</mml:mi>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:msub>
<mml:mi>I</mml:mi>
<mml:mrow>
<mml:mi>o</mml:mi>
<mml:mi>r</mml:mi>
<mml:mi>g</mml:mi>
<mml:mi>i</mml:mi>
<mml:mi>n</mml:mi>
<mml:mi>a</mml:mi>
<mml:mi>l</mml:mi>
</mml:mrow>
</mml:msub>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:math>
</inline-formula>
</p>
</list-item>
<list-item>
<p>4:&#x2003;<bold>do</bold>
</p>
</list-item>
<list-item>
<p>5:&#x2003;<bold>Generate a deblurred image</bold> <inline-formula id="inf48">
<mml:math id="m54">
<mml:mrow>
<mml:msub>
<mml:mi>I</mml:mi>
<mml:mrow>
<mml:mi>s</mml:mi>
<mml:mi>y</mml:mi>
<mml:mi>n</mml:mi>
<mml:mi>t</mml:mi>
<mml:mi>h</mml:mi>
<mml:mi>e</mml:mi>
<mml:mi>t</mml:mi>
<mml:mi>i</mml:mi>
<mml:mi>c</mml:mi>
</mml:mrow>
</mml:msub>
<mml:mo>&#x3d;</mml:mo>
<mml:mi>G</mml:mi>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:msub>
<mml:mi>I</mml:mi>
<mml:mrow>
<mml:mi>b</mml:mi>
<mml:mi>l</mml:mi>
<mml:mi>u</mml:mi>
<mml:mi>r</mml:mi>
<mml:mi>r</mml:mi>
<mml:mi>e</mml:mi>
<mml:mi>d</mml:mi>
</mml:mrow>
</mml:msub>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:math>
</inline-formula>&#x2003;&#x2003;&#x2003;using <inline-formula id="inf49">
<mml:math id="m55">
<mml:mrow>
<mml:mi>G</mml:mi>
</mml:mrow>
</mml:math>
</inline-formula> on an image <inline-formula id="inf50">
<mml:math id="m56">
<mml:mrow>
<mml:msub>
<mml:mi>I</mml:mi>
<mml:mrow>
<mml:mi>b</mml:mi>
<mml:mi>l</mml:mi>
<mml:mi>u</mml:mi>
<mml:mi>r</mml:mi>
<mml:mi>r</mml:mi>
<mml:mi>e</mml:mi>
<mml:mi>d</mml:mi>
</mml:mrow>
</mml:msub>
</mml:mrow>
</mml:math>
</inline-formula>
</p>
</list-item>
<list-item>
<p>6:&#x2003;Train <inline-formula id="inf51">
<mml:math id="m57">
<mml:mrow>
<mml:mi mathvariant="bold-italic">D</mml:mi>
<mml:mo>:</mml:mo>
</mml:mrow>
</mml:math>
</inline-formula> <inline-formula id="inf52">
<mml:math id="m58">
<mml:mrow>
<mml:msub>
<mml:mi>I</mml:mi>
<mml:mrow>
<mml:mi>s</mml:mi>
<mml:mi>y</mml:mi>
<mml:mi>n</mml:mi>
<mml:mi>t</mml:mi>
<mml:mi>h</mml:mi>
<mml:mi>e</mml:mi>
<mml:mi>t</mml:mi>
<mml:mi>i</mml:mi>
<mml:mi>c</mml:mi>
</mml:mrow>
</mml:msub>
</mml:mrow>
</mml:math>
</inline-formula> from original <inline-formula id="inf53">
<mml:math id="m59">
<mml:mrow>
<mml:msub>
<mml:mi>I</mml:mi>
<mml:mrow>
<mml:mi>o</mml:mi>
<mml:mi>r</mml:mi>
<mml:mi>i</mml:mi>
<mml:mi>g</mml:mi>
<mml:mi>i</mml:mi>
<mml:mi>n</mml:mi>
<mml:mi>a</mml:mi>
<mml:mi>l</mml:mi>
</mml:mrow>
</mml:msub>
</mml:mrow>
</mml:math>
</inline-formula>, to&#x2003;&#x2003;&#x2003;classify images accurately.</p>
</list-item>
<list-item>
<p>7:&#x2003;<bold>Update G</bold> using <bold>Wasserstein distance</bold>&#x2003;&#x2003;&#x2003;<inline-formula id="inf54">
<mml:math id="m60">
<mml:mrow>
<mml:mi>W</mml:mi>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:msub>
<mml:mi>P</mml:mi>
<mml:mi>r</mml:mi>
</mml:msub>
<mml:mo>,</mml:mo>
<mml:msub>
<mml:mi>P</mml:mi>
<mml:mi>g</mml:mi>
</mml:msub>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
<mml:mo>&#x3d;</mml:mo>
<mml:munder>
<mml:mi>inf</mml:mi>
<mml:mrow>
<mml:mi mathvariant="normal">&#x3b3;</mml:mi>
<mml:mo>&#x2208;</mml:mo>
<mml:mi mathvariant="normal">&#x3a0;</mml:mi>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:msub>
<mml:mi>P</mml:mi>
<mml:mi>r</mml:mi>
</mml:msub>
<mml:mo>,</mml:mo>
<mml:msub>
<mml:mi>P</mml:mi>
<mml:mi>g</mml:mi>
</mml:msub>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:munder>
<mml:msub>
<mml:mi>E</mml:mi>
<mml:mrow>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:mi>x</mml:mi>
<mml:mo>,</mml:mo>
<mml:mi>y</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
<mml:mo>&#x223c;</mml:mo>
<mml:mi mathvariant="normal">&#x3b3;</mml:mi>
</mml:mrow>
</mml:msub>
<mml:mrow>
<mml:mfenced open="[" close="]" separators="|">
<mml:mrow>
<mml:mfenced open="&#x2016;" close="&#x2016;" separators="|">
<mml:mrow>
<mml:mi>x</mml:mi>
<mml:mo>&#x2212;</mml:mo>
<mml:mi>y</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:math>
</inline-formula>
</p>
</list-item>
<list-item>
<p>8:&#x2003;Optimize both G and D using their respective&#x2003;&#x2003;&#x2003;objective functions:</p>
</list-item>
<list-item>
<p>9:&#x2003;For <bold>D, maximize:</bold> <inline-formula id="inf55">
<mml:math id="m61">
<mml:mrow>
<mml:msub>
<mml:mi>L</mml:mi>
<mml:mi>D</mml:mi>
</mml:msub>
<mml:mo>&#x3d;</mml:mo>
<mml:mo>&#x2212;</mml:mo>
<mml:mi>E</mml:mi>
<mml:mrow>
<mml:mfenced open="[" close="]" separators="|">
<mml:mrow>
<mml:mi>D</mml:mi>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:msub>
<mml:mi>I</mml:mi>
<mml:mrow>
<mml:mi>o</mml:mi>
<mml:mi>r</mml:mi>
<mml:mi>i</mml:mi>
<mml:mi>g</mml:mi>
<mml:mi>i</mml:mi>
<mml:mi>n</mml:mi>
<mml:mi>a</mml:mi>
<mml:mi>l</mml:mi>
</mml:mrow>
</mml:msub>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
<mml:mo>&#x2b;</mml:mo>
<mml:mi>E</mml:mi>
<mml:mrow>
<mml:mfenced open="[" close="]" separators="|">
<mml:mrow>
<mml:mi>D</mml:mi>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:msub>
<mml:mi>I</mml:mi>
<mml:mrow>
<mml:mi>s</mml:mi>
<mml:mi>y</mml:mi>
<mml:mi>n</mml:mi>
<mml:mi>t</mml:mi>
<mml:mi>h</mml:mi>
<mml:mi>e</mml:mi>
<mml:mi>t</mml:mi>
<mml:mi>i</mml:mi>
<mml:mi>c</mml:mi>
</mml:mrow>
</mml:msub>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:math>
</inline-formula> &#x2003;&#x2003;&#x2003;<inline-formula id="inf55a">
<mml:math id="m61b">
<mml:mrow>
<mml:mo>&#x2b;</mml:mo>
<mml:mi>&#x3bb;</mml:mi>
<mml:mo>&#x22c5;</mml:mo>
<mml:mi>E</mml:mi>
<mml:mrow>
<mml:mfenced open="[" close="]" separators="|">
<mml:mrow>
<mml:msup>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:mfenced open="|" close="" separators="|">
<mml:mrow>
<mml:mrow>
<mml:mo>&#x2207;</mml:mo>
<mml:mi>D</mml:mi>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:mi>I</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
<mml:msub>
<mml:mo>&#x7c;</mml:mo>
<mml:mn>2</mml:mn>
</mml:msub>
<mml:mo>&#x2212;</mml:mo>
<mml:mn>1</mml:mn>
</mml:mrow>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
<mml:mn>2</mml:mn>
</mml:msup>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:math>
</inline-formula>
</p>
</list-item>
<list-item>
<p>10:&#x2003;For <bold>G, minimize</bold> the <bold>Wasserstein distance</bold> to &#x2003;&#x2003;&#x2003;&#x2003;adjust its parameters effectively</p>
</list-item>
<list-item>
<p>11:&#x2003;<bold>while</bold> (D fails to distinguish from original &#x2003;&#x2003;&#x2003;&#x2003;images)</p>
</list-item>
<list-item>
<p>12:&#x2003;<bold>for</bold> the deblurred training sketch samples, <bold>do</bold>
</p>
</list-item>
<list-item>
<p>13:&#x2003;<bold>Sample batch</bold> of <inline-formula id="inf56">
<mml:math id="m62">
<mml:mrow>
<mml:mi>m</mml:mi>
</mml:mrow>
</mml:math>
</inline-formula> <bold>noise samples</bold> from prior &#x2003;&#x2003;&#x2003; <bold>noise</bold> <inline-formula id="inf57">
<mml:math id="m63">
<mml:mrow>
<mml:msub>
<mml:mi>p</mml:mi>
<mml:mi>g</mml:mi>
</mml:msub>
<mml:mrow>
<mml:mfenced open="(" close=")" separators="|">
<mml:mrow>
<mml:mi>n</mml:mi>
<mml:mi>o</mml:mi>
<mml:mi>i</mml:mi>
<mml:mi>s</mml:mi>
<mml:mi>e</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:math>
</inline-formula>
</p>
</list-item>
<list-item>
<p>14:&#x2003;Sample batch of images from the data</p>
</list-item>
<list-item>
<p>15:&#x2003;update <bold>discriminator</bold> functions &#x2003;&#x2003;&#x2003; <inline-formula id="inf58">
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<list-item>
<p>16:&#x2003;sample batch of <bold>m noise sample</bold>s for image</p>
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<list-item>
<p>17:&#x2003;update the <bold>generator</bold> using gradient &#x2003;&#x2003;&#x2003;&#x2003;functions. <inline-formula id="inf59">
<mml:math id="m65">
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<p>18:&#x2003;<bold>end for</bold>
</p>
</list-item>
<list-item>
<p>19:&#x2003;<bold>done</bold>
</p>
</list-item>
</list>
</p>
</statement>
</p>
<p>The CAT (Lines 3&#x2013;5) sharpens blurred images by enhancing edges, converting to grayscale, blending to emphasize structures, and refining pixels for clearer sketches. DeblurGAN (Lines 8&#x2013;14) employs a GAN framework to enhance sketch clarity, with a generator creating deblurred images and a discriminator refining accuracy by distinguishing them from sharp images. The Sketch_to_Photo_GAN (Lines 17&#x2013;23) turns deblurred sketches into photorealistic images through iterative training, aligning outputs closely with input sketches.</p>
</sec>
<sec sec-type="results" id="s5">
<title>5 Results</title>
<p>This section outlines the outcomes achieved through the experimental investigation of our proposed image deblurring framework. The system was implemented on a high-performance setup with Dual NVIDIA Tesla P100 GPUs, each with 3584 cores and 18.7 Teraflops of power, and Dual Intel Xeon E5-2609V4 CPUs, with 8 cores at 1.7 GHz and 128 GB RAM. To evaluate the outcomes, the following referential metrics are used: SSIM, PSNR, DIQA SRCC, DIQA PLCC, and AE. Additionally, non-referential metrics such as NIQE, BRISQUE, FID, and IS are also employed (<xref ref-type="bibr" rid="B28">Sannidhan et al., 2019</xref>; <xref ref-type="bibr" rid="B11">Hu et al., 2023</xref>; <xref ref-type="bibr" rid="B21">Martis et al., 2024</xref>).</p>
<sec id="s5-1">
<title>5.1 Dataset description</title>
<p>As previously mentioned, this study utilized photographic images from four datasets: 1) the Acne Recognition Dataset (<xref ref-type="bibr" rid="B14">Kucev, 2023</xref>), comprising 220 images, 2) the CUHK dataset (<xref ref-type="bibr" rid="B37">Wang and Tang, 2008</xref>), containing 188 images, 3) the AR dataset (<xref ref-type="bibr" rid="B3">Cao et al., 2022</xref>), featuring 200 images, and 4) the XM2GTS dataset (<xref ref-type="bibr" rid="B22">Messer et al., 1999</xref>), which includes 42 images. Using these images required sketches are generated through CAT. These datasets initially contained no blurred images. Therefore, Gaussian blur (<xref ref-type="bibr" rid="B1">Ai et al., 2023</xref>) was applied with kernel 5 &#xd7; 5 to blur the images. The four datasets used in this study were consistently divided into training and testing sets with a split ratio of 70% for training, and 30% each for testing.</p>
</sec>
<sec id="s5-2">
<title>5.2 Assessment of CAT&#x2019;s effect on deblurring module</title>
<p>This section explores the impact of CAT on the DeBlurring Module applied to the datasets described in <xref ref-type="sec" rid="s5-1">Section 5.1</xref>. The effectiveness of CAT in improving image quality is evaluated using the metrics discussed earlier, and the results are presented in <xref ref-type="table" rid="T1">Table 1</xref>.</p>
<table-wrap id="T1" position="float">
<label>TABLE 1</label>
<caption>
<p>Evaluation of CAT&#x2019;s effectiveness on the deblurring module across datasets.</p>
</caption>
<table>
<thead valign="top">
<tr>
<th rowspan="3" align="left">Evaluation metric</th>
<th colspan="8" align="center">Dataset</th>
</tr>
<tr>
<th colspan="2" align="left">Acne recognition dataset</th>
<th colspan="2" align="left">CUHK</th>
<th colspan="2" align="left">AR</th>
<th colspan="2" align="left">XM2GTS</th>
</tr>
<tr>
<th align="left">With CAT</th>
<th align="left">Without CAT</th>
<th align="left">With CAT</th>
<th align="left">Without CAT</th>
<th align="left">With CAT</th>
<th align="left">Without CAT</th>
<th align="left">With CAT</th>
<th align="left">Without CAT</th>
</tr>
</thead>
<tbody valign="top">
<tr>
<td align="left">NIQE &#x2193;</td>
<td align="left">2.35</td>
<td align="left">4.01</td>
<td align="left">2.27</td>
<td align="left">3.94</td>
<td align="left">2.55</td>
<td align="left">3.53</td>
<td align="left">2.76</td>
<td align="left">3.35</td>
</tr>
<tr>
<td align="left">BRISQUE &#x2193;</td>
<td align="left">28.36</td>
<td align="left">38.15</td>
<td align="left">25.38</td>
<td align="left">37.6</td>
<td align="left">20.1</td>
<td align="left">38.16</td>
<td align="left">38.25</td>
<td align="left">43.25</td>
</tr>
<tr>
<td align="left">DIQA SRCC &#x2191;</td>
<td align="left">0.91</td>
<td align="left">0.62</td>
<td align="left">0.97</td>
<td align="left">0.63</td>
<td align="left">0.74</td>
<td align="left">0.72</td>
<td align="left">0.78</td>
<td align="left">0.74</td>
</tr>
<tr>
<td align="left">DIQA PLCC &#x2191;</td>
<td align="left">1.01</td>
<td align="left">0.61</td>
<td align="left">0.86</td>
<td align="left">0.56</td>
<td align="left">0.9</td>
<td align="left">0.62</td>
<td align="left">0.85</td>
<td align="left">0.6</td>
</tr>
<tr>
<td align="left">SSIM &#x2191;</td>
<td align="left">0.83</td>
<td align="left">0.53</td>
<td align="left">0.86</td>
<td align="left">0.77</td>
<td align="left">0.91</td>
<td align="left">0.54</td>
<td align="left">0.88</td>
<td align="left">0.72</td>
</tr>
<tr>
<td align="left">PSNR &#x2191;</td>
<td align="left">22.35</td>
<td align="left">18.21</td>
<td align="left">24.01</td>
<td align="left">21.97</td>
<td align="left">28.48</td>
<td align="left">22.71</td>
<td align="left">30.73</td>
<td align="left">25.37</td>
</tr>
<tr>
<td align="left">AE &#x2193;</td>
<td align="left">22.25</td>
<td align="left">94.38</td>
<td align="left">25.35</td>
<td align="left">89.42</td>
<td align="left">38.85</td>
<td align="left">96.15</td>
<td align="left">71.41</td>
<td align="left">122.59</td>
</tr>
<tr>
<td align="left">FID &#x2193;</td>
<td align="left">10.77</td>
<td align="left">13.48</td>
<td align="left">10.11</td>
<td align="left">16.23</td>
<td align="left">9.7</td>
<td align="left">13.98</td>
<td align="left">9.81</td>
<td align="left">15.54</td>
</tr>
<tr>
<td align="left">IS &#x2191;</td>
<td align="left">3.4</td>
<td align="left">1.86</td>
<td align="left">2.87</td>
<td align="left">1.58</td>
<td align="left">2.92</td>
<td align="left">1.91</td>
<td align="left">3.2</td>
<td align="left">2.08</td>
</tr>
</tbody>
</table>
</table-wrap>
<p>
<xref ref-type="table" rid="T1">Table 1</xref> demonstrates that the application of CAT leads to significant improvements across all metrics. Notably, the SSIM shows an average increase of 35% across all datasets. This improvement highlights CAT&#x2019;s effectiveness in preserving critical structural details.</p>
</sec>
<sec id="s5-3">
<title>5.3 Assessment of CAT&#x2019;s effect on the image translator module</title>
<p>This section examines the impact of CAT on the image translator module in producing photo images from sketches. The evaluation utilizes sketches generated by the deblurring module, both with and without CAT, as input to the image translator module. <xref ref-type="table" rid="T2">Table 2</xref> summarizes the findings, including both non-referential and referential metrics previously discussed, with the data reflecting average values across all datasets outlined in <xref ref-type="sec" rid="s5-1">Section 5.1</xref>.</p>
<table-wrap id="T2" position="float">
<label>TABLE 2</label>
<caption>
<p>Impact of CAT on image translator module.</p>
</caption>
<table>
<thead valign="top">
<tr>
<th align="left">Evaluation metric</th>
<th align="left">With CAT</th>
<th align="left">Without CAT</th>
</tr>
</thead>
<tbody valign="top">
<tr>
<td align="left">NIQE <inline-formula id="inf60">
<mml:math id="m66">
<mml:mrow>
<mml:mo>&#x2193;</mml:mo>
</mml:mrow>
</mml:math>
</inline-formula>
</td>
<td align="left">2.4</td>
<td align="left">3.6</td>
</tr>
<tr>
<td align="left">BRISQUE <inline-formula id="inf61">
<mml:math id="m67">
<mml:mrow>
<mml:mo>&#x2193;</mml:mo>
</mml:mrow>
</mml:math>
</inline-formula>
</td>
<td align="left">28</td>
<td align="left">45</td>
</tr>
<tr>
<td align="left">DIQA SRCC <inline-formula id="inf62">
<mml:math id="m68">
<mml:mrow>
<mml:mo>&#x2191;</mml:mo>
</mml:mrow>
</mml:math>
</inline-formula>
</td>
<td align="left">0.89</td>
<td align="left">0.69</td>
</tr>
<tr>
<td align="left">DIQA PLCC <inline-formula id="inf63">
<mml:math id="m69">
<mml:mrow>
<mml:mo>&#x2191;</mml:mo>
</mml:mrow>
</mml:math>
</inline-formula>
</td>
<td align="left">0.84</td>
<td align="left">0.65</td>
</tr>
<tr>
<td align="left">SSIM <inline-formula id="inf64">
<mml:math id="m70">
<mml:mrow>
<mml:mo>&#x2191;</mml:mo>
</mml:mrow>
</mml:math>
</inline-formula>
</td>
<td align="left">0.85</td>
<td align="left">0.62</td>
</tr>
<tr>
<td align="left">PSNR <inline-formula id="inf65">
<mml:math id="m71">
<mml:mrow>
<mml:mo>&#x2191;</mml:mo>
</mml:mrow>
</mml:math>
</inline-formula>
</td>
<td align="left">25</td>
<td align="left">20</td>
</tr>
<tr>
<td align="left">AE <inline-formula id="inf66">
<mml:math id="m72">
<mml:mrow>
<mml:mo>&#x2193;</mml:mo>
</mml:mrow>
</mml:math>
</inline-formula>
</td>
<td align="left">40</td>
<td align="left">100</td>
</tr>
<tr>
<td align="left">FID&#x2193;</td>
<td align="left">15</td>
<td align="left">30</td>
</tr>
<tr>
<td align="left">IS&#x2191;</td>
<td align="left">3.2</td>
<td align="left">2.5</td>
</tr>
</tbody>
</table>
</table-wrap>
<p>The data in <xref ref-type="table" rid="T2">Table 2</xref> shows significant improvements with CAT across all the metrics confirming the impact of CAT aiding the generation of better-quality photos.</p>
</sec>
<sec id="s5-4">
<title>5.4 Visual gallery</title>
<p>This section presents a visual gallery depicting image synthesis evolution during training. <xref ref-type="fig" rid="F4">Figure 4A</xref> illustrates the deblurring process across adopted datasets, transitioning from Ground images to Blurred inputs, blurred sketch produced by CAT and clear photo from image translator module. Further 4 b) presents visual analysis of deblurring using Wiener Filtering and Richardson-Lucy Deconvolution.</p>
<fig id="F4" position="float">
<label>FIGURE 4</label>
<caption>
<p>
<bold>(A)</bold> Visualization of the proposed image deblurring framework <bold>(B)</bold> Visual comparison of deblurring results using Wiener Filtering and Richardson-Lucy deconvolution.</p>
</caption>
<graphic xlink:href="fbinf-05-1485797-g004.tif"/>
</fig>
</sec>
<sec id="s5-5">
<title>5.5 Comparative analysis with existing approaches</title>
<p>
<xref ref-type="table" rid="T3">Table 3</xref> presents a comparative analysis of the proposed image deblurring framework against existing image enhancement and GAN-based deblurring techniques. The results represent the average values obtained across the adopted datasets.</p>
<table-wrap id="T3" position="float">
<label>TABLE 3</label>
<caption>
<p>Comparison of the proposed image deblurring framework with existing techniques.</p>
</caption>
<table>
<thead valign="top">
<tr>
<th align="center">Evaluation method</th>
<th align="center">Technique</th>
<th align="center">NIQE &#x2193;</th>
<th align="center">BRISQUE&#x2193;</th>
<th align="center">DIQA SRCC &#x2191;</th>
<th align="center">DIQA PLCC &#x2191;</th>
<th align="center">SSIM &#x2191;</th>
<th align="center">PSNR &#x2191;</th>
<th align="center">AE &#x2193;</th>
<th align="center">FID &#x2193;</th>
<th align="center">IS &#x2191;</th>
</tr>
</thead>
<tbody valign="top">
<tr>
<td rowspan="4" align="center">Comparison of the image deblurring framework against traditional enhancement techniques</td>
<td align="left">Fusion of Median and Wiener filter (<xref ref-type="bibr" rid="B20">Martis and Balasubramani, 2020</xref>)</td>
<td align="center">4.2</td>
<td align="center">47</td>
<td align="center">0.53</td>
<td align="center">0.54</td>
<td align="center">0.58</td>
<td align="center">16</td>
<td align="center">135</td>
<td align="center">34</td>
<td align="center">1.05</td>
</tr>
<tr>
<td align="left">Unsharp mask guided filtering (<xref ref-type="bibr" rid="B30">Shi et al., 2021</xref>)</td>
<td align="center">3.8</td>
<td align="center">39</td>
<td align="center">0.61</td>
<td align="center">0.67</td>
<td align="center">0.63</td>
<td align="center">18</td>
<td align="center">101</td>
<td align="center">27</td>
<td align="center">1.81</td>
</tr>
<tr>
<td align="left">Adaptive color correction technique (<xref ref-type="bibr" rid="B18">Lin et al., 2023</xref>)</td>
<td align="center">3.1</td>
<td align="center">33</td>
<td align="center">0.69</td>
<td align="center">0.71</td>
<td align="center">0.72</td>
<td align="center">20</td>
<td align="center">72</td>
<td align="center">23</td>
<td align="center">2.4</td>
</tr>
<tr>
<td align="left">Proposed image deblurring framework</td>
<td align="center">2.4</td>
<td align="center">28</td>
<td align="center">0.89</td>
<td align="center">0.84</td>
<td align="center">0.85</td>
<td align="center">25</td>
<td align="center">40</td>
<td align="center">15</td>
<td align="center">3.2</td>
</tr>
<tr>
<td rowspan="7" align="center">Comparison of the image deblurring framework against existing GAN models for deblurring</td>
<td align="left">Semantic face Deblur GAN (<xref ref-type="bibr" rid="B17">Lee et al., 2020</xref>)</td>
<td align="center">4.6</td>
<td align="center">80</td>
<td align="center">0.44</td>
<td align="center">0.40</td>
<td align="center">0.49</td>
<td align="center">11</td>
<td align="center">82</td>
<td align="center">49</td>
<td align="center">1.7</td>
</tr>
<tr>
<td align="left">Realistic Deblurring (<xref ref-type="bibr" rid="B17">Lee et al., 2020</xref>)</td>
<td align="center">4.1</td>
<td align="center">64</td>
<td align="center">0.49</td>
<td align="center">0.46</td>
<td align="center">0.56</td>
<td align="center">13</td>
<td align="center">78</td>
<td align="center">44</td>
<td align="center">1.9</td>
</tr>
<tr>
<td align="left">Face Image Deblurring (<xref ref-type="bibr" rid="B26">Qi et al., 2021</xref>)</td>
<td align="center">3.8</td>
<td align="center">58</td>
<td align="center">0.54</td>
<td align="center">0.57</td>
<td align="center">0.61</td>
<td align="center">16</td>
<td align="center">71</td>
<td align="center">40</td>
<td align="center">2.4</td>
</tr>
<tr>
<td align="left">Guided Face Deblurring (<xref ref-type="bibr" rid="B13">Jung et al., 2022</xref>)</td>
<td align="center">3.8</td>
<td align="center">61</td>
<td align="center">0.62</td>
<td align="center">0.69</td>
<td align="center">0.62</td>
<td align="center">18</td>
<td align="center">69</td>
<td align="center">38</td>
<td align="center">2.3</td>
</tr>
<tr>
<td align="left">Style GAN (<xref ref-type="bibr" rid="B7">Collins et al., 2020</xref>)</td>
<td align="center">2.7</td>
<td align="center">32</td>
<td align="center">0.65</td>
<td align="center">0.72</td>
<td align="center">0.73</td>
<td align="center">21</td>
<td align="center">65</td>
<td align="center">25</td>
<td align="center">2.4</td>
</tr>
<tr>
<td align="left">ESIDformer (<xref ref-type="bibr" rid="B5">Chen et al., 2023</xref>)</td>
<td align="center">3.2</td>
<td align="center">48</td>
<td align="center">0.73</td>
<td align="center">0.76</td>
<td align="center">0.75</td>
<td align="center">14</td>
<td align="center">64</td>
<td align="center">27</td>
<td align="center">2.3</td>
</tr>
<tr>
<td align="left">Proposed image deblurring framework</td>
<td align="center">2.4</td>
<td align="center">28</td>
<td align="center">0.89</td>
<td align="center">0.84</td>
<td align="center">0.85</td>
<td align="center">25</td>
<td align="center">40</td>
<td align="center">15</td>
<td align="center">3.2</td>
</tr>
</tbody>
</table>
</table-wrap>
</sec>
</sec>
<sec sec-type="conclusion" id="s6">
<title>6 Conclusion</title>
<p>In this paper, we propose an image deblurring framework to address blurring issues in teledermatology, with a particular focus on acne images. The framework is designed to deblur images and enhance their clarity through three core modules: the Contour Accentuation Technique (CAT), the deblurring module, and the image translator module. The CAT module forms the foundation of the framework, extracting facial contours from blurred images and generating a blurred sketch to aid the deblurring process in the next module. The deblurring module enhances the clarity of the sketch produced by the CAT module by removing blur. Finally, the image translator module transforms the refined sketch into a photo image, offering a realistic view. Experimental analysis shows that incorporating CAT significantly improves the quality of the generated photo images. The proposed image deblurring framework on comparison achieved notable results, demonstrating superior performance over existing methods. In future, this research work can be extended to support and automate the acne severity assessment, aiding dermatologists in making faster and more accurate diagnoses.</p>
</sec>
</body>
<back>
<sec sec-type="data-availability" id="s7">
<title>Data availability statement</title>
<p>The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding authors.</p>
</sec>
<sec sec-type="author-contributions" id="s8">
<title>Author contributions</title>
<p>PM: Conceptualization, Methodology, Writing&#x2013;original draft. Sannidhan MS: Conceptualization, Methodology, Writing&#x2013;original draft, Writing&#x2013;review and editing. AP: Conceptualization, Funding acquisition, Methodology, Project administration, Writing&#x2013;review and editing. DC: Formal Analysis, Funding acquisition, Resources, Writing&#x2013;review and editing. JM: Writing&#x2013;review and editing.</p>
</sec>
<sec sec-type="funding-information" id="s9">
<title>Funding</title>
<p>The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. This is funded for open access publication upon acceptance by Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, 576104, India and NMAM Institute of Technology, Nitte Deemed to be University.</p>
</sec>
<sec sec-type="COI-statement" id="s10">
<title>Conflict of interest</title>
<p>The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.</p>
</sec>
<sec sec-type="disclaimer" id="s11">
<title>Publisher&#x2019;s note</title>
<p>All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.</p>
</sec>
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