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<h1>contrast.h File Reference</h1>
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This graph shows which files directly or indirectly include this file:</div>
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<a href="contrast_8h_source.html">Go to the source code of this file.</a><table border="0" cellpadding="0" cellspacing="0">
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<tr><td colspan="2"><br><h2>Functions</h2></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">QImage * </td><td class="memItemRight" valign="bottom"><a class="el" href="contrast_8h.html#5a7a57ce540b35b0987153951f45a398">enhanceImageContrast</a> (QString filename, <a class="el" href="classStatusWidget.html">StatusWidget</a> *<a class="el" href="redEye__internal_8h.html#65b682074aef9e63bb1dad48c3e9e9df">status</a>)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="contrast_8h.html#00f1d7b1aeff3381f41fa67e0f8a334b">enhanceImageContrast</a> (QImage *image, <a class="el" href="classStatusWidget.html">StatusWidget</a> *<a class="el" href="redEye__internal_8h.html#65b682074aef9e63bb1dad48c3e9e9df">status</a>=NULL)</td></tr>
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<hr><h2>Function Documentation</h2>
<a class="anchor" name="00f1d7b1aeff3381f41fa67e0f8a334b"></a><!-- doxytag: member="contrast.h::enhanceImageContrast" ref="00f1d7b1aeff3381f41fa67e0f8a334b" args="(QImage *image, StatusWidget *status=NULL)" -->
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<td class="memname">void enhanceImageContrast </td>
<td>(</td>
<td class="paramtype">QImage * </td>
<td class="paramname"> <em>image</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="classStatusWidget.html">StatusWidget</a> * </td>
<td class="paramname"> <em>status</em> = <code>NULL</code></td><td> </td>
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<td>)</td>
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<p>
------ Contrast stretching - <a href="http://www.ph.tn.tudelft.nl/Courses/FIP/frames/fip-istogram.html">http://www.ph.tn.tudelft.nl/Courses/FIP/frames/fip-istogram.html</a> -------
<p>Definition at line <a class="el" href="contrast_8cpp_source.html#l00105">105</a> of file <a class="el" href="contrast_8cpp_source.html">contrast.cpp</a>.</p>
<p>References <a class="el" href="jpegInternal_8h_source.html#l00125">b</a>, <a class="el" href="imageTools_8cpp_source.html#l00264">HSVtoRGB()</a>, <a class="el" href="statusWidget_8cpp_source.html#l00119">StatusWidget::incrementProgress()</a>, <a class="el" href="redEye__internal_8h_source.html#l00031">newProgress</a>, <a class="el" href="imageTools_8cpp_source.html#l00231">RGBtoHSV()</a>, <a class="el" href="imageTools_8cpp_source.html#l00217">RGBtoL()</a>, <a class="el" href="statusWidget_8cpp_source.html#l00125">StatusWidget::setStatus()</a>, <a class="el" href="statusWidget_8cpp_source.html#l00089">StatusWidget::showProgressBar()</a>, and <a class="el" href="redEye__internal_8h_source.html#l00028">updateIncrement</a>.</p>
<div class="fragment"><pre class="fragment"><a name="l00106"></a>00106 {
<a name="l00107"></a>00107 <span class="comment">//setup progress bar</span>
<a name="l00108"></a>00108 <span class="keywordflow">if</span>(status)
<a name="l00109"></a>00109 {
<a name="l00110"></a>00110 QString statusMessage = qApp->translate( <span class="stringliteral">"enhanceImageContrast"</span>, <span class="stringliteral">"Enhancing Contrast:"</span> );
<a name="l00111"></a>00111 status-><a class="code" href="classStatusWidget.html#57d461014070b9d651c36bd157cab9c1" title="Initializes the progress bar.">showProgressBar</a>( statusMessage, 100 );
<a name="l00112"></a>00112 qApp->processEvents();
<a name="l00113"></a>00113 }
<a name="l00114"></a>00114
<a name="l00115"></a>00115 <span class="comment">//update progress bar for every 1% of completion</span>
<a name="l00116"></a>00116 <span class="keyword">const</span> <span class="keywordtype">int</span> <a class="code" href="redEye__internal_8h.html#32598f506d413f48cda8e1c930dae6b3">updateIncrement</a> = (int) ( 0.01 * <a class="code" href="redEye__internal_8h.html#63116a8b94b4ed0e99ddcb7f6f3bd919">editedImage</a>->width() * <a class="code" href="redEye__internal_8h.html#63116a8b94b4ed0e99ddcb7f6f3bd919">editedImage</a>->height() );
<a name="l00117"></a>00117 <span class="keywordtype">int</span> <a class="code" href="redEye__internal_8h.html#caa08422437cae250a76ca488cbe1567">newProgress</a> = 0;
<a name="l00118"></a>00118
<a name="l00122"></a>00122
<a name="l00123"></a>00123 <span class="comment">//construct intensity histograph</span>
<a name="l00124"></a>00124 <span class="keywordtype">int</span> grayVals[256];
<a name="l00125"></a>00125 <span class="keywordtype">int</span> i=0;
<a name="l00126"></a>00126 <span class="keywordflow">for</span>(i=0; i<256; i++) { grayVals[i] = 0; }
<a name="l00127"></a>00127
<a name="l00128"></a>00128 <span class="comment">//populate histogram by iterating over all image pixels</span>
<a name="l00129"></a>00129 <span class="keywordtype">int</span> numPixels = <a class="code" href="redEye__internal_8h.html#63116a8b94b4ed0e99ddcb7f6f3bd919">editedImage</a>->width()*<a class="code" href="redEye__internal_8h.html#63116a8b94b4ed0e99ddcb7f6f3bd919">editedImage</a>->height();
<a name="l00130"></a>00130 QRgb* rgb;
<a name="l00131"></a>00131 <span class="keywordtype">double</span> grayValue;
<a name="l00132"></a>00132 uchar* scanLine;
<a name="l00133"></a>00133 <span class="keywordtype">int</span> x, y;
<a name="l00134"></a>00134 <span class="keywordflow">for</span>( y=0; y<<a class="code" href="redEye__internal_8h.html#63116a8b94b4ed0e99ddcb7f6f3bd919">editedImage</a>->height(); y++)
<a name="l00135"></a>00135 {
<a name="l00136"></a>00136 <span class="comment">//iterate over each selected pixel in scanline</span>
<a name="l00137"></a>00137 scanLine = <a class="code" href="redEye__internal_8h.html#63116a8b94b4ed0e99ddcb7f6f3bd919">editedImage</a>->scanLine(y);
<a name="l00138"></a>00138 <span class="keywordflow">for</span>( x=0; x<<a class="code" href="redEye__internal_8h.html#63116a8b94b4ed0e99ddcb7f6f3bd919">editedImage</a>->width(); x++)
<a name="l00139"></a>00139 {
<a name="l00140"></a>00140 rgb = ((QRgb*)scanLine+x);
<a name="l00141"></a>00141 grayValue = <a class="code" href="imageTools_8cpp.html#88f4928313fa9ef0e9232f3087189b65" title="find luminance of a rgb color triplet">RGBtoL</a>(rgb);
<a name="l00142"></a>00142 grayVals[(int)grayValue]++;
<a name="l00143"></a>00143 } <span class="comment">//for x</span>
<a name="l00144"></a>00144 } <span class="comment">//for y</span>
<a name="l00145"></a>00145
<a name="l00146"></a>00146 <span class="comment">//find 1% and 99% precenticles</span>
<a name="l00147"></a>00147 <span class="comment">//we'll stretch these values so we avoid outliers from affecting the stretch</span>
<a name="l00148"></a>00148 <span class="keywordtype">int</span> sum=0;
<a name="l00149"></a>00149 <span class="keywordtype">double</span> indexLow, indexHigh;
<a name="l00150"></a>00150 indexLow = -1.0; indexHigh = -1.0;
<a name="l00151"></a>00151 <span class="keywordflow">for</span>(i=0; i<256; i++)
<a name="l00152"></a>00152 {
<a name="l00153"></a>00153 sum+=grayVals[i];
<a name="l00154"></a>00154
<a name="l00155"></a>00155 <span class="comment">//if 1% not found yet and criteria met set index</span>
<a name="l00156"></a>00156 <span class="keywordflow">if</span>(indexLow < 0 &&
<a name="l00157"></a>00157 sum >= 0.01*numPixels)
<a name="l00158"></a>00158 {
<a name="l00159"></a>00159 indexLow = ((double)i)/255.0;
<a name="l00160"></a>00160 }
<a name="l00161"></a>00161
<a name="l00162"></a>00162 <span class="comment">//if 99% not found yet and criteria met set index</span>
<a name="l00163"></a>00163 <span class="keywordflow">if</span>(indexHigh < 0 &&
<a name="l00164"></a>00164 sum >= 0.99*numPixels)
<a name="l00165"></a>00165 {
<a name="l00166"></a>00166 indexHigh = ((double)i)/255.0;
<a name="l00167"></a>00167 }
<a name="l00168"></a>00168 }
<a name="l00169"></a>00169
<a name="l00170"></a>00170 <span class="comment">//only apply scaling if indexHigh > indexLow</span>
<a name="l00171"></a>00171 <span class="keywordflow">if</span>(indexHigh > indexLow)
<a name="l00172"></a>00172 {
<a name="l00173"></a>00173 <span class="comment">//run through all image pixels a second time, this time scaling coordinates as necessary</span>
<a name="l00174"></a>00174 <span class="keywordflow">for</span>( y=0; y<<a class="code" href="redEye__internal_8h.html#63116a8b94b4ed0e99ddcb7f6f3bd919">editedImage</a>->height(); y++)
<a name="l00175"></a>00175 {
<a name="l00176"></a>00176 <span class="comment">//iterate over each selected pixel in scanline</span>
<a name="l00177"></a>00177 scanLine = <a class="code" href="redEye__internal_8h.html#63116a8b94b4ed0e99ddcb7f6f3bd919">editedImage</a>->scanLine(y);
<a name="l00178"></a>00178 <span class="keywordflow">for</span>( x=0; x<<a class="code" href="redEye__internal_8h.html#63116a8b94b4ed0e99ddcb7f6f3bd919">editedImage</a>->width(); x++)
<a name="l00179"></a>00179 {
<a name="l00180"></a>00180 <span class="comment">//get color coordinates and convert to 0-1 scale</span>
<a name="l00181"></a>00181 rgb = ((QRgb*)scanLine+x);
<a name="l00182"></a>00182 <span class="keywordtype">double</span> r = ((double)qRed(*rgb) )/255.0;
<a name="l00183"></a>00183 <span class="keywordtype">double</span> g = ((double)qGreen(*rgb) )/255.0;
<a name="l00184"></a>00184 <span class="keywordtype">double</span> <a class="code" href="jpegInternal_8h.html#f320905358fa78701e4cc60b6135601f">b</a> = ((double)qBlue(*rgb) )/255.0;
<a name="l00185"></a>00185
<a name="l00186"></a>00186 <span class="comment">//convert to hsv</span>
<a name="l00187"></a>00187 <span class="keywordtype">double</span> h,s,v;
<a name="l00188"></a>00188 <a class="code" href="imageTools_8cpp.html#7769c25727d6caedf20321d238b3828d" title="Convert a RGB color triplet to HSV.">RGBtoHSV</a>(r,g,b,&h,&s,&v);
<a name="l00189"></a>00189
<a name="l00190"></a>00190 <span class="comment">//scale and clamp v</span>
<a name="l00191"></a>00191 v = (v-indexLow)/(indexHigh-indexLow);
<a name="l00192"></a>00192
<a name="l00193"></a>00193 <span class="comment">//convert adjusted color back to rgb colorspace and clamp</span>
<a name="l00194"></a>00194 <a class="code" href="imageTools_8cpp.html#a4ea508b635b1a7648bb5834132d4681" title="Convert a HSV color triplet to RGB.">HSVtoRGB</a>( &r,&g,&b, h,s,v);
<a name="l00195"></a>00195 <span class="keywordtype">int</span> rp = (int) QMIN( QMAX((r*255), 0), 255 );
<a name="l00196"></a>00196 <span class="keywordtype">int</span> gp = (int) QMIN( QMAX((g*255), 0), 255 );
<a name="l00197"></a>00197 <span class="keywordtype">int</span> bp = (int) QMIN( QMAX((b*255), 0), 255 );
<a name="l00198"></a>00198
<a name="l00199"></a>00199 <span class="comment">//set adjusted color value</span>
<a name="l00200"></a>00200 *rgb = qRgb(rp,gp,bp);
<a name="l00201"></a>00201
<a name="l00202"></a>00202 <span class="comment">//update status bar if significant progress has been made since last update</span>
<a name="l00203"></a>00203 <span class="keywordflow">if</span>(status)
<a name="l00204"></a>00204 {
<a name="l00205"></a>00205 newProgress++;
<a name="l00206"></a>00206 <span class="keywordflow">if</span>(newProgress >= updateIncrement)
<a name="l00207"></a>00207 {
<a name="l00208"></a>00208 newProgress = 0;
<a name="l00209"></a>00209 status-><a class="code" href="classStatusWidget.html#de18735223ae40506c32c96b9c9c5476" title="Updates the progress bar by one step.">incrementProgress</a>();
<a name="l00210"></a>00210 qApp->processEvents();
<a name="l00211"></a>00211 }
<a name="l00212"></a>00212 }
<a name="l00213"></a>00213
<a name="l00214"></a>00214 } <span class="comment">//for x</span>
<a name="l00215"></a>00215 } <span class="comment">//for y</span>
<a name="l00216"></a>00216 } <span class="comment">//if scaling should be preforemd</span>
<a name="l00217"></a>00217
<a name="l00218"></a>00218 <span class="comment">//remove status bar</span>
<a name="l00219"></a>00219 <span class="keywordflow">if</span>(status)
<a name="l00220"></a>00220 {
<a name="l00221"></a>00221 status-><a class="code" href="classStatusWidget.html#02084869ff1c15dab4bc922a49b31808" title="Update message.">setStatus</a>( <span class="stringliteral">""</span> );
<a name="l00222"></a>00222 qApp->processEvents();
<a name="l00223"></a>00223 }
<a name="l00224"></a>00224 }
</pre></div>
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<a class="anchor" name="5a7a57ce540b35b0987153951f45a398"></a><!-- doxytag: member="contrast.h::enhanceImageContrast" ref="5a7a57ce540b35b0987153951f45a398" args="(QString filename, StatusWidget *status)" -->
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<td class="memname">QImage* enhanceImageContrast </td>
<td>(</td>
<td class="paramtype">QString </td>
<td class="paramname"> <em>filename</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="classStatusWidget.html">StatusWidget</a> * </td>
<td class="paramname"> <em>status</em></td><td> </td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td><td></td>
</tr>
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</div>
<div class="memdoc">
<p>
<p>Definition at line <a class="el" href="contrast_8cpp_source.html#l00085">85</a> of file <a class="el" href="contrast_8cpp_source.html">contrast.cpp</a>.</p>
<p>References <a class="el" href="redEye__internal_8h_source.html#l00037">editedImage</a>, and <a class="el" href="contrast_8cpp_source.html#l00085">enhanceImageContrast()</a>.</p>
<p>Referenced by <a class="el" href="edgeDetect_8cpp_source.html#l00859">EdgeDetect::constructEdgeImage()</a>, <a class="el" href="editingInterface_8cpp_source.html#l00650">EditingInterface::enhanceContrast()</a>, and <a class="el" href="contrast_8cpp_source.html#l00085">enhanceImageContrast()</a>.</p>
<div class="fragment"><pre class="fragment"><a name="l00086"></a>00086 {
<a name="l00087"></a>00087 <span class="comment">//load original image</span>
<a name="l00088"></a>00088 QImage* <a class="code" href="redEye__internal_8h.html#63116a8b94b4ed0e99ddcb7f6f3bd919">editedImage</a> = <span class="keyword">new</span> QImage( filename );
<a name="l00089"></a>00089
<a name="l00090"></a>00090 <span class="comment">//convert to 32-bit depth if necessary</span>
<a name="l00091"></a>00091 <span class="keywordflow">if</span>( editedImage->depth() < 32 )
<a name="l00092"></a>00092 {
<a name="l00093"></a>00093 QImage* tmp = editedImage;
<a name="l00094"></a>00094 editedImage = <span class="keyword">new</span> QImage( tmp->convertDepth( 32, Qt::AutoColor ) );
<a name="l00095"></a>00095 <span class="keyword">delete</span> tmp; tmp=NULL;
<a name="l00096"></a>00096 }
<a name="l00097"></a>00097
<a name="l00098"></a>00098 <span class="comment">//enhance contrast</span>
<a name="l00099"></a>00099 <a class="code" href="contrast_8cpp.html#5a7a57ce540b35b0987153951f45a398">enhanceImageContrast</a>( editedImage, status );
<a name="l00100"></a>00100
<a name="l00101"></a>00101 <span class="comment">//return pointer to edited image</span>
<a name="l00102"></a>00102 <span class="keywordflow">return</span> editedImage;
<a name="l00103"></a>00103 }
</pre></div>
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