{"id":2107,"date":"2026-10-27T11:19:40","date_gmt":"2026-10-27T10:19:40","guid":{"rendered":"https:\/\/au.feri.um.si\/losdv\/projekti\/pegasti-sum-sar\/"},"modified":"2026-10-28T09:38:27","modified_gmt":"2026-10-28T08:38:27","slug":"pegasti-sum-sar","status":"publish","type":"page","link":"https:\/\/au.feri.um.si\/losdv\/en\/projekti\/pegasti-sum-sar\/","title":{"rendered":"Removing speckle noise from SAR images"},"content":{"rendered":"<section class=\"wp-block-group alignfull au-section au-section--dark au-projhero is-layout-flow wp-block-group-is-layout-flow\">\n<div class=\"wp-block-group au-container is-layout-flow wp-block-group-is-layout-flow\">\n<p class=\"au-back wp-block-paragraph\"><a href=\"\/losdv\/en\/#iz-nasega-dela\">\u2190 Projects and theses<\/a><\/p>\n\n\n<p class=\"au-eyebrow wp-block-paragraph\">01.7 \u00b7 Master's thesis<\/p>\n\n\n<h1 class=\"wp-block-heading\">Removing speckle noise from SAR images<\/h1>\n\n\n<p class=\"au-lead wp-block-paragraph\">A deep neural network removes grainy speckle noise from a radar image while preserving edges and details.<\/p>\n\n\n<div class=\"anim-box wide\">\n      <canvas id=\"anim\" aria-label=\"Slider over a Sentinel-1 image of the Maribor area: to the left of the slider a single image with speckle noise, to the right the average of more than 400 images of the same area. The right half shows a zoomed detail, marked with a red square.\"><\/canvas>\n      <div class=\"anim-cap mono\"><span>Sentinel-1 \u00b7 Maribor \u00b7 a single noisy image \u2194 average of more than 400 images \u00b7 zoomed detail on the right<\/span><button class=\"anim-toggle\" type=\"button\">Stop<\/button><\/div>\n    <\/div>\n<\/div>\n<\/section>\n\n\n\n<section class=\"wp-block-group alignfull au-section is-layout-flow wp-block-group-is-layout-flow\">\n<div class=\"wp-block-group au-container is-layout-flow wp-block-group-is-layout-flow\">\n<div class=\"wp-block-columns au-projbody is-layout-flex wp-container-core-columns-is-layout-89c98654 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:60%\">\n<h2 class=\"wp-block-heading\">About the project<\/h2>\n\n\n<p class=\"wp-block-paragraph\">SAR radar images are covered by grainy speckle noise that makes them hard to interpret. Deep neural networks remove it while preserving edges and details \u2013 a basis for more accurate image analysis.<\/p>\n\n\n<p class=\"wp-block-paragraph\">Speckle noise ( <em>speckle<\/em>) is not a sensor fault but a consequence of coherent imaging: the reflections of many small scatterers within one resolution cell add up with different phases. Classic filters reduce the noise but also blur the edges. A neural network learns to separate noise from structure in the image.<\/p>\n\n\n<p class=\"wp-block-paragraph\">For training, the network needs pairs of images: a noisy image and a clean reference image of the same area. The master's thesis uses a multi-temporal approach \u2013 the reference image of the Maribor area is the average of more than 400 Sentinel-1 images. Averaging cancels the speckle noise, which is random from image to image, while the terrain structure remains.<\/p>\n\n\n<h2 class=\"wp-block-heading\">How it works<\/h2>\n\n\n<ol class=\"wp-block-list au-steps\">\n<li><strong>Data preparation<\/strong>: Sentinel-1 images of the same location are processed, co-registered and terrain-corrected.<\/li>\n\n\n<li><strong>The reference image<\/strong> is obtained by averaging more than 400 co-registered images.<\/li>\n\n\n<li><strong>A convolutional network<\/strong> with an encoder and decoder and a continuous attention module (CAM) learns the mapping from the noisy image to the reference image.<\/li>\n\n\n<li><strong>Comparison<\/strong> with eight classic filters (Boxcar, Median, Frost, Gamma MAP, Lee, Refined Lee, Lee Sigma, IDAN) using PSNR and SSIM \u2013 deep learning achieved the best results.<\/li>\n<\/ol>\n<\/div>\n\n\n<div class=\"wp-block-column au-facts is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:40%\">\n<figure class=\"wp-block-table au-facts__table\"><table class=\"has-fixed-layout\"><tbody><tr><td>Type<\/td><td>Master's thesis<\/td><\/tr><tr><td>Author<\/td><td>Tadej Habjani\u010d<\/td><\/tr><tr><td>Supervisor<\/td><td>Du\u0161an Gleich<\/td><\/tr><tr><td>Field<\/td><td>Remote sensing \u00b7 Radar signal processing<\/td><\/tr><tr><td>Data<\/td><td>Sentinel-1, Maribor area<\/td><\/tr><tr><td>Reference<\/td><td>Average of more than 400 images<\/td><\/tr><tr><td>Method<\/td><td>Encoder-decoder CNN with a CAM attention module<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n<figure data-wp-context=\"{&quot;imageId&quot;:&quot;6aef773bef97a&quot;}\" data-wp-interactive=\"core\/image\" data-wp-key=\"6aef773bef97a\" class=\"wp-block-image size-full wp-lightbox-container\"><img decoding=\"async\" data-wp-class--hide=\"state.isContentHidden\" data-wp-class--show=\"state.isContentVisible\" data-wp-init=\"callbacks.setButtonStyles\" data-wp-on--click=\"actions.showLightbox\" data-wp-on--load=\"callbacks.setButtonStyles\" data-wp-on--pointerdown=\"actions.preloadImage\" data-wp-on--pointerenter=\"actions.preloadImageWithDelay\" data-wp-on--pointerleave=\"actions.cancelPreload\" data-wp-on-window--resize=\"callbacks.setButtonStyles\" src=\"\/losdv\/wp-content\/uploads\/sites\/4\/2026\/10\/s1-maribor-povprecje-kvadrat.jpg\" alt=\"Povpre\u010dje ve\u010d kot 400 posnetkov Sentinel-1 okolice Maribora\"\/><button\n\t\t\tclass=\"lightbox-trigger\"\n\t\t\ttype=\"button\"\n\t\t\taria-haspopup=\"dialog\"\n\t\t\tdata-wp-bind--aria-label=\"state.thisImage.triggerButtonAriaLabel\"\n\t\t\tdata-wp-init=\"callbacks.initTriggerButton\"\n\t\t\tdata-wp-on--click=\"actions.showLightbox\"\n\t\t\tdata-wp-style--right=\"state.thisImage.buttonRight\"\n\t\t\tdata-wp-style--top=\"state.thisImage.buttonTop\"\n\t\t>\n\t\t\t<svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"12\" height=\"12\" fill=\"none\" viewbox=\"0 0 12 12\">\n\t\t\t\t<path fill=\"#fff\" d=\"M2 0a2 2 0 0 0-2 2v2h1.5V2a.5.5 0 0 1 .5-.5h2V0H2Zm2 10.5H2a.5.5 0 0 1-.5-.5V8H0v2a2 2 0 0 0 2 2h2v-1.5ZM8 12v-1.5h2a.5.5 0 0 0 .5-.5V8H12v2a2 2 0 0 1-2 2H8Zm2-12a2 2 0 0 1 2 2v2h-1.5V2a.5.5 0 0 0-.5-.5H8V0h2Z\" \/>\n\t\t\t<\/svg>\n\t\t<\/button><\/figure>\n\n\n<p class=\"au-textlink wp-block-paragraph\"><a href=\"https:\/\/dk.um.si\/IzpisGradiva.php?id=86581\" target=\"_blank\" rel=\"noreferrer noopener\">Read in DKUM \u2197<\/a><\/p>\n<\/div>\n<\/div>\n\n\n<div class=\"wp-block-group au-projsec is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\">Zoomed detail: noise, deep learning and reference<\/h2>\n\n\n<div class=\"wp-block-group au-zoomrow is-layout-flow wp-block-group-is-layout-flow\">\n<figure data-wp-context=\"{&quot;imageId&quot;:&quot;6aef773bf0247&quot;}\" data-wp-interactive=\"core\/image\" data-wp-key=\"6aef773bf0247\" class=\"wp-block-image size-full wp-lightbox-container\"><img decoding=\"async\" data-wp-class--hide=\"state.isContentHidden\" data-wp-class--show=\"state.isContentVisible\" data-wp-init=\"callbacks.setButtonStyles\" data-wp-on--click=\"actions.showLightbox\" data-wp-on--load=\"callbacks.setButtonStyles\" data-wp-on--pointerdown=\"actions.preloadImage\" data-wp-on--pointerenter=\"actions.preloadImageWithDelay\" data-wp-on--pointerleave=\"actions.cancelPreload\" data-wp-on-window--resize=\"callbacks.setButtonStyles\" src=\"\/losdv\/wp-content\/uploads\/sites\/4\/2026\/10\/s1-izsek-sum.jpg\" alt=\"Izsek posnetka Sentinel-1 s pegastim \u0161umom\"\/><button\n\t\t\tclass=\"lightbox-trigger\"\n\t\t\ttype=\"button\"\n\t\t\taria-haspopup=\"dialog\"\n\t\t\tdata-wp-bind--aria-label=\"state.thisImage.triggerButtonAriaLabel\"\n\t\t\tdata-wp-init=\"callbacks.initTriggerButton\"\n\t\t\tdata-wp-on--click=\"actions.showLightbox\"\n\t\t\tdata-wp-style--right=\"state.thisImage.buttonRight\"\n\t\t\tdata-wp-style--top=\"state.thisImage.buttonTop\"\n\t\t>\n\t\t\t<svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"12\" height=\"12\" fill=\"none\" viewbox=\"0 0 12 12\">\n\t\t\t\t<path fill=\"#fff\" d=\"M2 0a2 2 0 0 0-2 2v2h1.5V2a.5.5 0 0 1 .5-.5h2V0H2Zm2 10.5H2a.5.5 0 0 1-.5-.5V8H0v2a2 2 0 0 0 2 2h2v-1.5ZM8 12v-1.5h2a.5.5 0 0 0 .5-.5V8H12v2a2 2 0 0 1-2 2H8Zm2-12a2 2 0 0 1 2 2v2h-1.5V2a.5.5 0 0 0-.5-.5H8V0h2Z\" \/>\n\t\t\t<\/svg>\n\t\t<\/button><figcaption class=\"wp-element-caption\">A single noisy image<\/figcaption><\/figure>\n\n\n<figure data-wp-context=\"{&quot;imageId&quot;:&quot;6aef773bf052c&quot;}\" data-wp-interactive=\"core\/image\" data-wp-key=\"6aef773bf052c\" class=\"wp-block-image size-full wp-lightbox-container\"><img decoding=\"async\" data-wp-class--hide=\"state.isContentHidden\" data-wp-class--show=\"state.isContentVisible\" data-wp-init=\"callbacks.setButtonStyles\" data-wp-on--click=\"actions.showLightbox\" data-wp-on--load=\"callbacks.setButtonStyles\" data-wp-on--pointerdown=\"actions.preloadImage\" data-wp-on--pointerenter=\"actions.preloadImageWithDelay\" data-wp-on--pointerleave=\"actions.cancelPreload\" data-wp-on-window--resize=\"callbacks.setButtonStyles\" src=\"\/losdv\/wp-content\/uploads\/sites\/4\/2026\/10\/s1-izsek-globoko.jpg\" alt=\"Isti izsek po odstranjevanju \u0161uma z globokim u\u010denjem\"\/><button\n\t\t\tclass=\"lightbox-trigger\"\n\t\t\ttype=\"button\"\n\t\t\taria-haspopup=\"dialog\"\n\t\t\tdata-wp-bind--aria-label=\"state.thisImage.triggerButtonAriaLabel\"\n\t\t\tdata-wp-init=\"callbacks.initTriggerButton\"\n\t\t\tdata-wp-on--click=\"actions.showLightbox\"\n\t\t\tdata-wp-style--right=\"state.thisImage.buttonRight\"\n\t\t\tdata-wp-style--top=\"state.thisImage.buttonTop\"\n\t\t>\n\t\t\t<svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"12\" height=\"12\" fill=\"none\" viewbox=\"0 0 12 12\">\n\t\t\t\t<path fill=\"#fff\" d=\"M2 0a2 2 0 0 0-2 2v2h1.5V2a.5.5 0 0 1 .5-.5h2V0H2Zm2 10.5H2a.5.5 0 0 1-.5-.5V8H0v2a2 2 0 0 0 2 2h2v-1.5ZM8 12v-1.5h2a.5.5 0 0 0 .5-.5V8H12v2a2 2 0 0 1-2 2H8Zm2-12a2 2 0 0 1 2 2v2h-1.5V2a.5.5 0 0 0-.5-.5H8V0h2Z\" \/>\n\t\t\t<\/svg>\n\t\t<\/button><figcaption class=\"wp-element-caption\">Deep learning<\/figcaption><\/figure>\n\n\n<figure data-wp-context=\"{&quot;imageId&quot;:&quot;6aef773bf0747&quot;}\" data-wp-interactive=\"core\/image\" data-wp-key=\"6aef773bf0747\" class=\"wp-block-image size-full wp-lightbox-container\"><img decoding=\"async\" data-wp-class--hide=\"state.isContentHidden\" data-wp-class--show=\"state.isContentVisible\" data-wp-init=\"callbacks.setButtonStyles\" data-wp-on--click=\"actions.showLightbox\" data-wp-on--load=\"callbacks.setButtonStyles\" data-wp-on--pointerdown=\"actions.preloadImage\" data-wp-on--pointerenter=\"actions.preloadImageWithDelay\" data-wp-on--pointerleave=\"actions.cancelPreload\" data-wp-on-window--resize=\"callbacks.setButtonStyles\" src=\"\/losdv\/wp-content\/uploads\/sites\/4\/2026\/10\/s1-izsek-povprecje.jpg\" alt=\"Isti izsek na povpre\u010dju ve\u010d kot 400 posnetkov\"\/><button\n\t\t\tclass=\"lightbox-trigger\"\n\t\t\ttype=\"button\"\n\t\t\taria-haspopup=\"dialog\"\n\t\t\tdata-wp-bind--aria-label=\"state.thisImage.triggerButtonAriaLabel\"\n\t\t\tdata-wp-init=\"callbacks.initTriggerButton\"\n\t\t\tdata-wp-on--click=\"actions.showLightbox\"\n\t\t\tdata-wp-style--right=\"state.thisImage.buttonRight\"\n\t\t\tdata-wp-style--top=\"state.thisImage.buttonTop\"\n\t\t>\n\t\t\t<svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"12\" height=\"12\" fill=\"none\" viewbox=\"0 0 12 12\">\n\t\t\t\t<path fill=\"#fff\" d=\"M2 0a2 2 0 0 0-2 2v2h1.5V2a.5.5 0 0 1 .5-.5h2V0H2Zm2 10.5H2a.5.5 0 0 1-.5-.5V8H0v2a2 2 0 0 0 2 2h2v-1.5ZM8 12v-1.5h2a.5.5 0 0 0 .5-.5V8H12v2a2 2 0 0 1-2 2H8Zm2-12a2 2 0 0 1 2 2v2h-1.5V2a.5.5 0 0 0-.5-.5H8V0h2Z\" \/>\n\t\t\t<\/svg>\n\t\t<\/button><figcaption class=\"wp-element-caption\">Average of 400+ images<\/figcaption><\/figure>\n<\/div>\n\n\n<p class=\"au-media-cap wp-block-paragraph\">The area marked with a red square in the image above. Images: T. Habjani\u010d, <em>Removing speckle noise from SAR images using deep learning<\/em>, master's thesis, UM FERI.<\/p>\n<\/div>\n\n\n<div class=\"wp-block-group au-projnav is-layout-flow wp-block-group-is-layout-flow\">\n<p class=\"wp-block-paragraph\"><a href=\"\/losdv\/en\/projekti\/kontrola-napisa-bosch\/\"><span>\u2190 Previous<\/span>Camera inspection of Bosch lettering<\/a><\/p>\n\n\n<p class=\"wp-block-paragraph\"><a href=\"\/losdv\/en\/projekti\/dvokolesni-robot\/\"><span>Next \u2192<\/span>Agile two-wheeled robot<\/a><\/p>\n<\/div>\n<\/div>\n<\/section>","protected":false},"excerpt":{"rendered":"<p>\u2190 Projekti in zaklju\u010dna dela 01.7 \u00b7 Magistrsko delo Odstranjevanje pegastega \u0161uma iz slik SAR Globoka nevronska mre\u017ea iz radarske slike odstrani zrnat pegasti \u0161um, robovi in podrobnosti pa ostanejo. Sentinel-1 \u00b7 Maribor \u00b7 en posnetek s \u0161umom \u2194 povpre\u010dje ve\u010d kot 400 posnetkov \u00b7 desno pribli\u017ean izsekUstavi O projektu Radarske slike SAR prekriva zrnat [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":2098,"menu_order":7,"comment_status":"closed","ping_status":"closed","template":"page-brez-naslova","meta":{"footnotes":""},"class_list":["post-2107","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/au.feri.um.si\/losdv\/en\/wp-json\/wp\/v2\/pages\/2107","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/au.feri.um.si\/losdv\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/au.feri.um.si\/losdv\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/au.feri.um.si\/losdv\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/au.feri.um.si\/losdv\/en\/wp-json\/wp\/v2\/comments?post=2107"}],"version-history":[{"count":2,"href":"https:\/\/au.feri.um.si\/losdv\/en\/wp-json\/wp\/v2\/pages\/2107\/revisions"}],"predecessor-version":[{"id":2130,"href":"https:\/\/au.feri.um.si\/losdv\/en\/wp-json\/wp\/v2\/pages\/2107\/revisions\/2130"}],"up":[{"embeddable":true,"href":"https:\/\/au.feri.um.si\/losdv\/en\/wp-json\/wp\/v2\/pages\/2098"}],"wp:attachment":[{"href":"https:\/\/au.feri.um.si\/losdv\/en\/wp-json\/wp\/v2\/media?parent=2107"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}