<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/> <meta http-equiv="X-UA-Compatible" content="IE=9"/> <meta name="generator" content="Doxygen 1.8.5"/> <title>NVIDIA 2D Image And Signal Performance Primitives (NPP): BGRToLab</title> <link href="tabs.css" rel="stylesheet" type="text/css"/> <script type="text/javascript" src="jquery.js"></script> <script type="text/javascript" src="dynsections.js"></script> <link href="search/search.css" rel="stylesheet" type="text/css"/> <script type="text/javascript" src="search/search.js"></script> <script type="text/javascript"> $(document).ready(function() { searchBox.OnSelectItem(0); }); </script> <link href="doxygen.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="top"><!-- do not remove this div, it is closed by doxygen! --> <div 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src="javascript:void(0)" frameborder="0" name="MSearchResults" id="MSearchResults"> </iframe> </div> <div class="header"> <div class="summary"> <a href="#func-members">Functions</a> </div> <div class="headertitle"> <div class="title">BGRToLab<div class="ingroups"><a class="el" href="group__image__color__model__conversion.html">Color Model Conversion</a></div></div> </div> </div><!--header--> <div class="contents"> <p>BGR to Lab color conversion. <a href="#details">More...</a></p> <table class="memberdecls"> <tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="func-members"></a> Functions</h2></td></tr> <tr class="memitem:gaa308d6db4b1f5587da7fc6d35cedf52f"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__typedefs__npp.html#ga1105a17b5e76381583c46ecd6a60fe21">NppStatus</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__bgrtolab.html#gaa308d6db4b1f5587da7fc6d35cedf52f">nppiBGRToLab_8u_C3R_Ctx</a> (const <a class="el" href="group__npp__basic__types.html#ga29b502b6816fc0066fd59538483a5b62">Npp8u</a> *pSrc, int nSrcStep, <a class="el" href="group__npp__basic__types.html#ga29b502b6816fc0066fd59538483a5b62">Npp8u</a> *pDst, int nDstStep, <a class="el" href="struct_nppi_size.html">NppiSize</a> oSizeROI, <a class="el" href="struct_npp_stream_context.html">NppStreamContext</a> nppStreamCtx)</td></tr> <tr class="memdesc:gaa308d6db4b1f5587da7fc6d35cedf52f"><td class="mdescLeft"> </td><td class="mdescRight">3 channel 8-bit unsigned packed BGR to 3 channel 8-bit unsigned packed Lab color conversion. <a href="#gaa308d6db4b1f5587da7fc6d35cedf52f">More...</a><br/></td></tr> <tr class="separator:gaa308d6db4b1f5587da7fc6d35cedf52f"><td class="memSeparator" colspan="2"> </td></tr> <tr class="memitem:gadd4ff1523afe525490de0eab1b999ac4"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__typedefs__npp.html#ga1105a17b5e76381583c46ecd6a60fe21">NppStatus</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__bgrtolab.html#gadd4ff1523afe525490de0eab1b999ac4">nppiBGRToLab_8u_C3R</a> (const <a class="el" href="group__npp__basic__types.html#ga29b502b6816fc0066fd59538483a5b62">Npp8u</a> *pSrc, int nSrcStep, <a class="el" href="group__npp__basic__types.html#ga29b502b6816fc0066fd59538483a5b62">Npp8u</a> *pDst, int nDstStep, <a class="el" href="struct_nppi_size.html">NppiSize</a> oSizeROI)</td></tr> <tr class="separator:gadd4ff1523afe525490de0eab1b999ac4"><td class="memSeparator" colspan="2"> </td></tr> </table> <a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2> <p>BGR to Lab color conversion. </p> <p>This is how NPP converts gamma corrected BGR or RGB to Lab using the CIE Lab D65 white point with a Y luminance of 1.0. The computed values of the L component are in the range [0..100], a and b component values are in the range [-128..127]. The code uses cbrtf() the 32 bit floating point cube root math function.</p> <div class="fragment"><div class="line">* <span class="comment">// use CIE Lab chromaticity coordinates</span></div> <div class="line">* #define nCIE_LAB_D65_xn 0.950455F</div> <div class="line">* #define nCIE_LAB_D65_yn 1.0F</div> <div class="line">* #define nCIE_LAB_D65_zn 1.088753F</div> <div class="line">* <span class="comment">// First convert to XYZ</span></div> <div class="line">* <a class="code" href="group__npp__basic__types.html#ga274ed0e3c4cbc89f644143f64e2391ee">Npp32f</a> nNormalizedR = (<a class="code" href="group__npp__basic__types.html#ga274ed0e3c4cbc89f644143f64e2391ee">Npp32f</a>)R * 0.003921569F; <span class="comment">// / 255.0F</span></div> <div class="line">* <a class="code" href="group__npp__basic__types.html#ga274ed0e3c4cbc89f644143f64e2391ee">Npp32f</a> nNormalizedG = (<a class="code" href="group__npp__basic__types.html#ga274ed0e3c4cbc89f644143f64e2391ee">Npp32f</a>)G * 0.003921569F;</div> <div class="line">* <a class="code" href="group__npp__basic__types.html#ga274ed0e3c4cbc89f644143f64e2391ee">Npp32f</a> nNormalizedB = (<a class="code" href="group__npp__basic__types.html#ga274ed0e3c4cbc89f644143f64e2391ee">Npp32f</a>)B * 0.003921569F;</div> <div class="line">* <a class="code" href="group__npp__basic__types.html#ga274ed0e3c4cbc89f644143f64e2391ee">Npp32f</a> nX = 0.412453F * nNormalizedR + 0.35758F * nNormalizedG + 0.180423F * nNormalizedB; </div> <div class="line">* <a class="code" href="group__npp__basic__types.html#ga274ed0e3c4cbc89f644143f64e2391ee">Npp32f</a> nY = 0.212671F * nNormalizedR + 0.71516F * nNormalizedG + 0.072169F * nNormalizedB;</div> <div class="line">* <a class="code" href="group__npp__basic__types.html#ga274ed0e3c4cbc89f644143f64e2391ee">Npp32f</a> nZ = 0.019334F * nNormalizedR + 0.119193F * nNormalizedG + 0.950227F * nNormalizedB;</div> <div class="line">* <a class="code" href="group__npp__basic__types.html#ga274ed0e3c4cbc89f644143f64e2391ee">Npp32f</a> nL = cbrtf(nY);</div> <div class="line">* <a class="code" href="group__npp__basic__types.html#ga274ed0e3c4cbc89f644143f64e2391ee">Npp32f</a> nA; <a class="code" href="group__npp__basic__types.html#ga274ed0e3c4cbc89f644143f64e2391ee">Npp32f</a> nB; <a class="code" href="group__npp__basic__types.html#ga274ed0e3c4cbc89f644143f64e2391ee">Npp32f</a> nfX = nX * 1.052128F; <span class="comment">// / nCIE_LAB_D65_xn; Npp32f nfY = nY; Npp32f nfZ = nZ * 0.918482F; // /</span></div> <div class="line">* nCIE_LAB_D65_zn; nfY = nL - 16.0F; nL = 116.0F * nL - 16.0F; nA = cbrtf(nfX) - 16.0F; nA = 500.0F</div> <div class="line">* * (nA - nfY); nB = cbrtf(nfZ) - 16.0F; nB = 200.0F * (nfY - nB); <span class="comment">// Now scale Lab range nL = nL * 255.0F</span></div> <div class="line">* * 0.01F; <span class="comment">// / 100.0F nA = nA + 128.0F; nB = nB + 128.0F; L = (Npp8u)nL; a = (Npp8u)nA; b = (Npp8u)nB;</span></div> <div class="line">* </div> </div><!-- fragment --> <h2 class="groupheader">Function Documentation</h2> <a class="anchor" id="gadd4ff1523afe525490de0eab1b999ac4"></a> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname"><a class="el" href="group__typedefs__npp.html#ga1105a17b5e76381583c46ecd6a60fe21">NppStatus</a> nppiBGRToLab_8u_C3R </td> <td>(</td> <td class="paramtype">const <a class="el" href="group__npp__basic__types.html#ga29b502b6816fc0066fd59538483a5b62">Npp8u</a> * </td> <td class="paramname"><em>pSrc</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">int </td> <td class="paramname"><em>nSrcStep</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"><a class="el" href="group__npp__basic__types.html#ga29b502b6816fc0066fd59538483a5b62">Npp8u</a> * </td> <td class="paramname"><em>pDst</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">int </td> <td class="paramname"><em>nDstStep</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"><a class="el" href="struct_nppi_size.html">NppiSize</a> </td> <td class="paramname"><em>oSizeROI</em> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td> </tr> </table> </div><div class="memdoc"> </div> </div> <a class="anchor" id="gaa308d6db4b1f5587da7fc6d35cedf52f"></a> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname"><a class="el" href="group__typedefs__npp.html#ga1105a17b5e76381583c46ecd6a60fe21">NppStatus</a> nppiBGRToLab_8u_C3R_Ctx </td> <td>(</td> <td class="paramtype">const <a class="el" href="group__npp__basic__types.html#ga29b502b6816fc0066fd59538483a5b62">Npp8u</a> * </td> <td class="paramname"><em>pSrc</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">int </td> <td class="paramname"><em>nSrcStep</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"><a class="el" href="group__npp__basic__types.html#ga29b502b6816fc0066fd59538483a5b62">Npp8u</a> * </td> <td class="paramname"><em>pDst</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">int </td> <td class="paramname"><em>nDstStep</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"><a class="el" href="struct_nppi_size.html">NppiSize</a> </td> <td class="paramname"><em>oSizeROI</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"><a class="el" href="struct_npp_stream_context.html">NppStreamContext</a> </td> <td class="paramname"><em>nppStreamCtx</em> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td> </tr> </table> </div><div class="memdoc"> <p>3 channel 8-bit unsigned packed BGR to 3 channel 8-bit unsigned packed Lab color conversion. </p> <dl class="params"><dt>Parameters</dt><dd> <table class="params"> <tr><td class="paramname">pSrc</td><td><a class="el" href="nppi_conventions_lb.html#source_image_pointer">Source-Image Pointer</a>. </td></tr> <tr><td class="paramname">nSrcStep</td><td><a class="el" href="nppi_conventions_lb.html#source_image_line_step">Source-Image Line Step</a>. </td></tr> <tr><td class="paramname">pDst</td><td><a class="el" href="nppi_conventions_lb.html#destination_image_pointer">Destination-Image Pointer</a>. </td></tr> <tr><td class="paramname">nDstStep</td><td><a class="el" href="nppi_conventions_lb.html#destination_image_line_step">Destination-Image Line Step</a>. </td></tr> <tr><td class="paramname">oSizeROI</td><td><a class="el" href="nppi_conventions_lb.html#roi_specification">Region-of-Interest (ROI)</a>. </td></tr> <tr><td class="paramname">nppStreamCtx</td><td><a class="el" href="index.html#application_managed_stream_context">Application Managed Stream Context</a>. </td></tr> </table> </dd> </dl> <dl class="section return"><dt>Returns</dt><dd><a class="el" href="nppi_conventions_lb.html#image_data_error_codes">Image Data Related Error Codes</a>, <a class="el" href="nppi_conventions_lb.html#roi_error_codes">ROI Related Error Codes</a> </dd></dl> </div> </div> </div><!-- contents --> <HR> <center>Copyright © 2009-2019 NVIDIA Corporation</center> <HR>