4 <title>ImageSqueeze - lossy image codec</title>
5 <!-- 2020-05-01 Fri 23:44 -->
7 <meta name="viewport" content="width=device-width, initial-scale=1">
8 <meta name="generator" content="Org-mode">
9 <meta name="author" content="Svjatoslav Agejenko">
10 <link href="https://bootswatch.com/3/darkly/bootstrap.min.css" rel="stylesheet">
11 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
12 <script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.5/js/bootstrap.min.js"></script>
13 <style type="text/css">
14 footer {background-color: #111 !important;}
15 pre {background-color: #111; color: #ccc;}
17 <style type="text/css">
18 /* org mode styles on top of twbs */
35 background-color: #f5f5f5;
62 display: inline-block;
74 .bs-docs-sidebar.affix {
77 @media (min-width: 768px) {
83 /* All levels of nav */
84 .bs-docs-sidebar .nav > li > a {
91 .bs-docs-sidebar .nav > li > a:hover,
92 .bs-docs-sidebar .nav > li > a:focus {
95 text-decoration: none;
96 background-color: transparent;
97 border-left: 1px solid #A1283B;
99 .bs-docs-sidebar .nav > .active > a,
100 .bs-docs-sidebar .nav > .active:hover > a,
101 .bs-docs-sidebar .nav > .active:focus > a {
105 background-color: transparent;
106 border-left: 2px solid #A1283B;
109 /* Nav: second level (shown on .active) */
110 .bs-docs-sidebar .nav .nav {
111 display: none; /* Hide by default, but at >768px, show it */
112 padding-bottom: 10px;
114 .bs-docs-sidebar .nav .nav > li > a {
121 .bs-docs-sidebar .nav .nav > li > a:hover,
122 .bs-docs-sidebar .nav .nav > li > a:focus {
125 .bs-docs-sidebar .nav .nav > .active > a,
126 .bs-docs-sidebar .nav .nav > .active:hover > a,
127 .bs-docs-sidebar .nav .nav > .active:focus > a {
132 /* Nav: third level (shown on .active) */
133 .bs-docs-sidebar .nav .nav .nav {
134 padding-bottom: 10px;
136 .bs-docs-sidebar .nav .nav .nav > li > a {
143 .bs-docs-sidebar .nav .nav .nav > li > a:hover,
144 .bs-docs-sidebar .nav .nav .nav > li > a:focus {
147 .bs-docs-sidebar .nav .nav .nav > .active > a,
148 .bs-docs-sidebar .nav .nav .nav > .active:hover > a,
149 .bs-docs-sidebar .nav .nav .nav > .active:focus > a {
154 /* Show and affix the side nav when space allows it */
155 @media (min-width: 992px) {
156 .bs-docs-sidebar .nav > .active > ul {
159 /* Widen the fixed sidebar */
160 .bs-docs-sidebar.affix,
161 .bs-docs-sidebar.affix-bottom {
164 .bs-docs-sidebar.affix {
165 position: fixed; /* Undo the static from mobile first approach */
168 .bs-docs-sidebar.affix-bottom {
169 position: absolute; /* Undo the static from mobile first approach */
171 .bs-docs-sidebar.affix .bs-docs-sidenav,.bs-docs-sidebar.affix-bottom .bs-docs-sidenav {
176 @media (min-width: 1200px) {
177 /* Widen the fixed sidebar again */
178 .bs-docs-sidebar.affix-bottom,
179 .bs-docs-sidebar.affix {
184 <script type="text/javascript">
188 $('.bs-docs-sidebar li').first().addClass('active');
190 $(document.body).scrollspy({target: '.bs-docs-sidebar'});
192 $('.bs-docs-sidebar').affix();
197 <div id="content" class="container">
198 <div class="row"><div class="col-md-9"><h1 class="title">ImageSqueeze - lossy image codec</h1>
199 <div id="outline-container-sec-1" class="outline-2">
200 <h2 id="sec-1"><span class="section-number-2">1</span> General</h2>
201 <div class="outline-text-2" id="text-1">
203 <li>This program is free software: released under Creative Commons Zero
209 <li>Svjatoslav Agejenko
211 <li>Homepage: <a href="https://svjatoslav.eu">https://svjatoslav.eu</a>
213 <li>Email: <a href="mailto://svjatoslav@svjatoslav.eu">mailto://svjatoslav@svjatoslav.eu</a>
218 <li><a href="https://www.svjatoslav.eu/projects/">Other software projects hosted at svjatoslav.eu</a>
223 <div id="outline-container-sec-1-1" class="outline-3">
224 <h3 id="sec-1-1"><span class="section-number-3">1.1</span> Source code</h3>
225 <div class="outline-text-3" id="text-1-1">
227 <li><a href="https://www2.svjatoslav.eu/gitweb/?p=imagesqueeze.git;a=snapshot;h=HEAD;sf=tgz">Download latest snapshot in TAR GZ format</a>
230 <li><a href="https://www2.svjatoslav.eu/gitweb/?p=imagesqueeze.git;a=summary">Browse Git repository online</a>
233 <li>Clone Git repository using command:
234 <pre class="example">
235 git clone https://www2.svjatoslav.eu/git/imagesqueeze.git
244 <div id="outline-container-sec-2" class="outline-2">
245 <h2 id="sec-2"><span class="section-number-2">2</span> Overview</h2>
246 <div class="outline-text-2" id="text-2">
248 Lossy image codec. Optimized for photos. I developed it to test out an
249 image compression ideas.
253 I believe my <a href="#sec-3-1">algorighm has interesting advantages.</a>
257 Below are original photo and the same image being compressed down to
258 ~93 Kb and then decompressed.
263 <p><img src="originalAndCompressed.png" class="img-responsive" alt="originalAndCompressed.png">
268 When looking very closely, slight grainyness, loss of color precision
269 and blurriness (loss of detail) could be noticed as a compression
270 artifacts. Still sharp edges are always preserved. Also no blocks
271 typical to JPEG are ever seen. I think that is awesome result for
272 just ~ 2.5 bits per pixel on that color photo.
276 <div id="outline-container-sec-3" class="outline-2">
277 <h2 id="sec-3"><span class="section-number-2">3</span> Algorithm description</h2>
278 <div class="outline-text-2" id="text-3">
280 <li>Color image is split into three separate channels: Y, U and V.
282 <li>Each channel is independently compressed.
287 <li>Single channel compression method:
290 <li>Algorithm is inspired by <a href="https://en.wikipedia.org/wiki/Diamond-square_algorithm">diamond-square algorithm</a> that is meant to
291 produce random heightmap/plasma effect.
294 <li>During image compression: 2D image surface is iterated in the
295 similar manner to diamond-square algorithm. Average color from
296 neighbors is calculated and difference between neighbors average
297 and actual pixel color is saved. As the pixel grid becomes
298 gradually more dense, difference between neighbors tends to get
299 smaller, thereby requiring less bits per pixel for storing the
306 <div id="outline-container-sec-3-1" class="outline-3">
307 <h3 id="sec-3-1"><a id="ID-1d917f74-e763-4a71-976e-4aa60732efa6" name="ID-1d917f74-e763-4a71-976e-4aa60732efa6"></a><span class="section-number-3">3.1</span> Algorighm advantages</h3>
308 <div class="outline-text-3" id="text-3-1">
310 <li>It can be applied to any amount of dimensions, even for sound and
314 <li>Algorithm can operate in lossy and lossless mode.
317 <li>Algorithm naturally handles progressive loading. That is: low
318 resolution thumbnail of entire thing is immediately available and
319 gets gradually more dense during entire loading process.
322 <li>Algorithm naturally supports variable resolution. That is: different
323 areas can be encoded with different resolutions / pixel densities.
326 <li>Fast: Very little computations per pixel.
333 <div id="outline-container-sec-4" class="outline-2">
334 <h2 id="sec-4"><span class="section-number-2">4</span> <span class="label label-primary TODO">TODO</span> Things to improve</h2>
335 <div class="outline-text-2" id="text-4">
337 <li>Code documentation is weak.
340 <li>Better sample applications needed:
342 <li>Commandline image conversion utility.
349 <li>Add lossless support.
352 <li>Extract algorithm key parts into reusable library and make it
353 variable dimensional. So that the same code can be used for sound,
354 image and volumetric data compression/decompression.
359 </div><div class="col-md-3"><nav id="table-of-contents">
360 <div id="text-table-of-contents" class="bs-docs-sidebar">
362 <li><a href="#sec-1">1. General</a>
364 <li><a href="#sec-1-1">1.1. Source code</a></li>
367 <li><a href="#sec-2">2. Overview</a></li>
368 <li><a href="#sec-3">3. Algorithm description</a>
370 <li><a href="#sec-3-1">3.1. Algorighm advantages</a></li>
373 <li><a href="#sec-4">4. Things to improve</a></li>
378 <footer id="postamble" class="">
379 <div><p class="author">Author: Svjatoslav Agejenko</p>
380 <p class="date">Created: 2020-05-01 Fri 23:44</p>
381 <p class="creator"><a href="http://www.gnu.org/software/emacs/">Emacs</a> 26.1 (<a href="http://orgmode.org">Org-mode</a> 9.1.9)</p>