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<div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno">    1</span>&#160;<span class="comment">//</span></div><div class="line"><a name="l00002"></a><span class="lineno">    2</span>&#160;<span class="comment">// Copyright 2019 Miral Shah &lt;miralshah2211@gmail.com&gt;</span></div><div class="line"><a name="l00003"></a><span class="lineno">    3</span>&#160;<span class="comment">//</span></div><div class="line"><a name="l00004"></a><span class="lineno">    4</span>&#160;<span class="comment">// Use, modification and distribution are subject to the Boost Software License,</span></div><div class="line"><a name="l00005"></a><span class="lineno">    5</span>&#160;<span class="comment">// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at</span></div><div class="line"><a name="l00006"></a><span class="lineno">    6</span>&#160;<span class="comment">// http://www.boost.org/LICENSE_1_0.txt)</span></div><div class="line"><a name="l00007"></a><span class="lineno">    7</span>&#160;<span class="comment">//</span></div><div class="line"><a name="l00008"></a><span class="lineno">    8</span>&#160;<span class="preprocessor">#ifndef BOOST_GIL_IMAGE_PROCESSING_THRESHOLD_HPP</span></div><div class="line"><a name="l00009"></a><span class="lineno">    9</span>&#160;<span class="preprocessor">#define BOOST_GIL_IMAGE_PROCESSING_THRESHOLD_HPP</span></div><div class="line"><a name="l00010"></a><span class="lineno">   10</span>&#160;</div><div class="line"><a name="l00011"></a><span class="lineno">   11</span>&#160;<span class="preprocessor">#include &lt;limits&gt;</span></div><div class="line"><a name="l00012"></a><span class="lineno">   12</span>&#160;<span class="preprocessor">#include &lt;array&gt;</span></div><div class="line"><a name="l00013"></a><span class="lineno">   13</span>&#160;<span class="preprocessor">#include &lt;type_traits&gt;</span></div><div class="line"><a name="l00014"></a><span class="lineno">   14</span>&#160;<span class="preprocessor">#include &lt;cstddef&gt;</span></div><div class="line"><a name="l00015"></a><span class="lineno">   15</span>&#160;<span class="preprocessor">#include &lt;algorithm&gt;</span></div><div class="line"><a name="l00016"></a><span class="lineno">   16</span>&#160;<span class="preprocessor">#include &lt;vector&gt;</span></div><div class="line"><a name="l00017"></a><span class="lineno">   17</span>&#160;<span class="preprocessor">#include &lt;cmath&gt;</span></div><div class="line"><a name="l00018"></a><span class="lineno">   18</span>&#160;</div><div class="line"><a name="l00019"></a><span class="lineno">   19</span>&#160;<span class="preprocessor">#include &lt;boost/assert.hpp&gt;</span></div><div class="line"><a name="l00020"></a><span class="lineno">   20</span>&#160;</div><div class="line"><a name="l00021"></a><span class="lineno">   21</span>&#160;<span class="preprocessor">#include &lt;boost/gil/image.hpp&gt;</span></div><div class="line"><a name="l00022"></a><span class="lineno">   22</span>&#160;<span class="preprocessor">#include &lt;boost/gil/extension/numeric/kernel.hpp&gt;</span></div><div class="line"><a name="l00023"></a><span class="lineno">   23</span>&#160;<span class="preprocessor">#include &lt;boost/gil/extension/numeric/convolve.hpp&gt;</span></div><div class="line"><a name="l00024"></a><span class="lineno">   24</span>&#160;<span class="preprocessor">#include &lt;boost/gil/image_processing/numeric.hpp&gt;</span></div><div class="line"><a name="l00025"></a><span class="lineno">   25</span>&#160;</div><div class="line"><a name="l00026"></a><span class="lineno">   26</span>&#160;<span class="keyword">namespace </span>boost { <span class="keyword">namespace </span>gil {</div><div class="line"><a name="l00027"></a><span class="lineno">   27</span>&#160;</div><div class="line"><a name="l00028"></a><span class="lineno">   28</span>&#160;<span class="keyword">namespace </span>detail {</div><div class="line"><a name="l00029"></a><span class="lineno">   29</span>&#160;</div><div class="line"><a name="l00030"></a><span class="lineno">   30</span>&#160;<span class="keyword">template</span></div><div class="line"><a name="l00031"></a><span class="lineno">   31</span>&#160;&lt;</div><div class="line"><a name="l00032"></a><span class="lineno">   32</span>&#160;    <span class="keyword">typename</span> SourceChannelT,</div><div class="line"><a name="l00033"></a><span class="lineno">   33</span>&#160;    <span class="keyword">typename</span> ResultChannelT,</div><div class="line"><a name="l00034"></a><span class="lineno">   34</span>&#160;    <span class="keyword">typename</span> SrcView,</div><div class="line"><a name="l00035"></a><span class="lineno">   35</span>&#160;    <span class="keyword">typename</span> DstView,</div><div class="line"><a name="l00036"></a><span class="lineno">   36</span>&#160;    <span class="keyword">typename</span> Operator</div><div class="line"><a name="l00037"></a><span class="lineno">   37</span>&#160;&gt;</div><div class="line"><a name="l00038"></a><span class="lineno">   38</span>&#160;<span class="keywordtype">void</span> threshold_impl(SrcView <span class="keyword">const</span>&amp; src_view, DstView <span class="keyword">const</span>&amp; dst_view, Operator <span class="keyword">const</span>&amp; threshold_op)</div><div class="line"><a name="l00039"></a><span class="lineno">   39</span>&#160;{</div><div class="line"><a name="l00040"></a><span class="lineno">   40</span>&#160;    gil_function_requires&lt;ImageViewConcept&lt;SrcView&gt;&gt;();</div><div class="line"><a name="l00041"></a><span class="lineno">   41</span>&#160;    gil_function_requires&lt;MutableImageViewConcept&lt;DstView&gt;&gt;();</div><div class="line"><a name="l00042"></a><span class="lineno">   42</span>&#160;    static_assert(color_spaces_are_compatible</div><div class="line"><a name="l00043"></a><span class="lineno">   43</span>&#160;    &lt;</div><div class="line"><a name="l00044"></a><span class="lineno">   44</span>&#160;        <span class="keyword">typename</span> color_space_type&lt;SrcView&gt;::type,</div><div class="line"><a name="l00045"></a><span class="lineno">   45</span>&#160;        <span class="keyword">typename</span> color_space_type&lt;DstView&gt;::type</div><div class="line"><a name="l00046"></a><span class="lineno">   46</span>&#160;    &gt;::value, <span class="stringliteral">&quot;Source and destination views must have pixels with the same color space&quot;</span>);</div><div class="line"><a name="l00047"></a><span class="lineno">   47</span>&#160;</div><div class="line"><a name="l00048"></a><span class="lineno">   48</span>&#160;    <span class="comment">//iterate over the image chaecking each pixel value for the threshold</span></div><div class="line"><a name="l00049"></a><span class="lineno">   49</span>&#160;    <span class="keywordflow">for</span> (std::ptrdiff_t y = 0; y &lt; src_view.height(); y++)</div><div class="line"><a name="l00050"></a><span class="lineno">   50</span>&#160;    {</div><div class="line"><a name="l00051"></a><span class="lineno">   51</span>&#160;        <span class="keyword">typename</span> SrcView::x_iterator src_it = src_view.row_begin(y);</div><div class="line"><a name="l00052"></a><span class="lineno">   52</span>&#160;        <span class="keyword">typename</span> DstView::x_iterator dst_it = dst_view.row_begin(y);</div><div class="line"><a name="l00053"></a><span class="lineno">   53</span>&#160;</div><div class="line"><a name="l00054"></a><span class="lineno">   54</span>&#160;        <span class="keywordflow">for</span> (std::ptrdiff_t x = 0; x &lt; src_view.width(); x++)</div><div class="line"><a name="l00055"></a><span class="lineno">   55</span>&#160;        {</div><div class="line"><a name="l00056"></a><span class="lineno">   56</span>&#160;            static_transform(src_it[x], dst_it[x], threshold_op);</div><div class="line"><a name="l00057"></a><span class="lineno">   57</span>&#160;        }</div><div class="line"><a name="l00058"></a><span class="lineno">   58</span>&#160;    }</div><div class="line"><a name="l00059"></a><span class="lineno">   59</span>&#160;}</div><div class="line"><a name="l00060"></a><span class="lineno">   60</span>&#160;</div><div class="line"><a name="l00061"></a><span class="lineno">   61</span>&#160;} <span class="comment">//namespace boost::gil::detail</span></div><div class="line"><a name="l00062"></a><span class="lineno">   62</span>&#160;</div><div class="line"><a name="l00069"></a><span class="lineno"><a class="line" href="group___image_processing.html#gae73d8b37c737a81ffa26b0c5c62d8f0e">   69</a></span>&#160;<span class="keyword">enum class</span> <a class="code" href="group___image_processing.html#gae73d8b37c737a81ffa26b0c5c62d8f0e">threshold_direction</a></div><div class="line"><a name="l00070"></a><span class="lineno">   70</span>&#160;{</div><div class="line"><a name="l00071"></a><span class="lineno">   71</span>&#160;    <a class="code" href="group___image_processing.html#ggae73d8b37c737a81ffa26b0c5c62d8f0eaaf37d08ae228a87dc6b265fd1019c97d">regular</a>, </div><div class="line"><a name="l00072"></a><span class="lineno">   72</span>&#160;    <a class="code" href="group___image_processing.html#ggae73d8b37c737a81ffa26b0c5c62d8f0eaa91c78e040f7b9d158f381e197f8beb4">inverse</a>  </div><div class="line"><a name="l00073"></a><span class="lineno">   73</span>&#160;};</div><div class="line"><a name="l00074"></a><span class="lineno">   74</span>&#160;</div><div class="line"><a name="l00077"></a><span class="lineno"><a class="line" href="group___image_processing.html#ga62185ec305fdb480a227c159b9fa5e84">   77</a></span>&#160;<span class="keyword">enum class</span> <a class="code" href="group___image_processing.html#ga62185ec305fdb480a227c159b9fa5e84">threshold_optimal_value</a></div><div class="line"><a name="l00078"></a><span class="lineno">   78</span>&#160;{</div><div class="line"><a name="l00079"></a><span class="lineno">   79</span>&#160;    <a class="code" href="group___image_processing.html#gga62185ec305fdb480a227c159b9fa5e84a3d734c6df06af2a3ac4e82483c51c455">otsu</a>        </div><div class="line"><a name="l00080"></a><span class="lineno">   80</span>&#160;};</div><div class="line"><a name="l00081"></a><span class="lineno">   81</span>&#160;</div><div class="line"><a name="l00084"></a><span class="lineno"><a class="line" href="group___image_processing.html#ga7b2c4d7867de63cfdc39c26d750efab0">   84</a></span>&#160;<span class="keyword">enum class</span> <a class="code" href="group___image_processing.html#ga7b2c4d7867de63cfdc39c26d750efab0">threshold_truncate_mode</a></div><div class="line"><a name="l00085"></a><span class="lineno">   85</span>&#160;{</div><div class="line"><a name="l00086"></a><span class="lineno">   86</span>&#160;    <a class="code" href="group___image_processing.html#gga7b2c4d7867de63cfdc39c26d750efab0af0598264a691a8f62272aca0e79af374">threshold</a>,  </div><div class="line"><a name="l00087"></a><span class="lineno">   87</span>&#160;    <a class="code" href="group___image_processing.html#gga7b2c4d7867de63cfdc39c26d750efab0ad02c4c4cde7ae76252540d116a40f23a">zero</a>        </div><div class="line"><a name="l00088"></a><span class="lineno">   88</span>&#160;};</div><div class="line"><a name="l00089"></a><span class="lineno">   89</span>&#160;</div><div class="line"><a name="l00090"></a><span class="lineno">   90</span>&#160;<span class="keyword">enum class</span> threshold_adaptive_method</div><div class="line"><a name="l00091"></a><span class="lineno">   91</span>&#160;{</div><div class="line"><a name="l00092"></a><span class="lineno">   92</span>&#160;    mean,</div><div class="line"><a name="l00093"></a><span class="lineno">   93</span>&#160;    gaussian</div><div class="line"><a name="l00094"></a><span class="lineno">   94</span>&#160;};</div><div class="line"><a name="l00095"></a><span class="lineno">   95</span>&#160;</div><div class="line"><a name="l00107"></a><span class="lineno">  107</span>&#160;<span class="keyword">template</span> &lt;<span class="keyword">typename</span> SrcView, <span class="keyword">typename</span> DstView&gt;</div><div class="line"><a name="l00108"></a><span class="lineno"><a class="line" href="group___image_processing.html#ga2074015c3ced619e9075909377c10d5f">  108</a></span>&#160;<span class="keywordtype">void</span> <a class="code" href="group___image_processing.html#gaeaf67a8717e170a8eacd7ca80273dd85">threshold_binary</a>(</div><div class="line"><a name="l00109"></a><span class="lineno">  109</span>&#160;    SrcView <span class="keyword">const</span>&amp; src_view,</div><div class="line"><a name="l00110"></a><span class="lineno">  110</span>&#160;    DstView <span class="keyword">const</span>&amp; dst_view,</div><div class="line"><a name="l00111"></a><span class="lineno">  111</span>&#160;    <span class="keyword">typename</span> <a class="code" href="structboost_1_1gil_1_1channel__type.html">channel_type&lt;DstView&gt;::type</a> threshold_value,</div><div class="line"><a name="l00112"></a><span class="lineno">  112</span>&#160;    <span class="keyword">typename</span> <a class="code" href="structboost_1_1gil_1_1channel__type.html">channel_type&lt;DstView&gt;::type</a> max_value,</div><div class="line"><a name="l00113"></a><span class="lineno">  113</span>&#160;    <a class="code" href="group___image_processing.html#gae73d8b37c737a81ffa26b0c5c62d8f0e">threshold_direction</a> direction = <a class="code" href="group___image_processing.html#ggae73d8b37c737a81ffa26b0c5c62d8f0eaaf37d08ae228a87dc6b265fd1019c97d">threshold_direction::regular</a></div><div class="line"><a name="l00114"></a><span class="lineno">  114</span>&#160;)</div><div class="line"><a name="l00115"></a><span class="lineno">  115</span>&#160;{</div><div class="line"><a name="l00116"></a><span class="lineno">  116</span>&#160;    <span class="comment">//deciding output channel type and creating functor</span></div><div class="line"><a name="l00117"></a><span class="lineno">  117</span>&#160;    <span class="keyword">using</span> source_channel_t = <span class="keyword">typename</span> <a class="code" href="structboost_1_1gil_1_1channel__type.html">channel_type&lt;SrcView&gt;::type</a>;</div><div class="line"><a name="l00118"></a><span class="lineno">  118</span>&#160;    <span class="keyword">using</span> result_channel_t = <span class="keyword">typename</span> <a class="code" href="structboost_1_1gil_1_1channel__type.html">channel_type&lt;DstView&gt;::type</a>;</div><div class="line"><a name="l00119"></a><span class="lineno">  119</span>&#160;</div><div class="line"><a name="l00120"></a><span class="lineno">  120</span>&#160;    <span class="keywordflow">if</span> (direction == <a class="code" href="group___image_processing.html#ggae73d8b37c737a81ffa26b0c5c62d8f0eaaf37d08ae228a87dc6b265fd1019c97d">threshold_direction::regular</a>)</div><div class="line"><a name="l00121"></a><span class="lineno">  121</span>&#160;    {</div><div class="line"><a name="l00122"></a><span class="lineno">  122</span>&#160;        detail::threshold_impl&lt;source_channel_t, result_channel_t&gt;(src_view, dst_view,</div><div class="line"><a name="l00123"></a><span class="lineno">  123</span>&#160;            [threshold_value, max_value](source_channel_t px) -&gt; result_channel_t {</div><div class="line"><a name="l00124"></a><span class="lineno">  124</span>&#160;                <span class="keywordflow">return</span> px &gt; threshold_value ? max_value : 0;</div><div class="line"><a name="l00125"></a><span class="lineno">  125</span>&#160;            });</div><div class="line"><a name="l00126"></a><span class="lineno">  126</span>&#160;    }</div><div class="line"><a name="l00127"></a><span class="lineno">  127</span>&#160;    <span class="keywordflow">else</span></div><div class="line"><a name="l00128"></a><span class="lineno">  128</span>&#160;    {</div><div class="line"><a name="l00129"></a><span class="lineno">  129</span>&#160;        detail::threshold_impl&lt;source_channel_t, result_channel_t&gt;(src_view, dst_view,</div><div class="line"><a name="l00130"></a><span class="lineno">  130</span>&#160;            [threshold_value, max_value](source_channel_t px) -&gt; result_channel_t {</div><div class="line"><a name="l00131"></a><span class="lineno">  131</span>&#160;                <span class="keywordflow">return</span> px &gt; threshold_value ? 0 : max_value;</div><div class="line"><a name="l00132"></a><span class="lineno">  132</span>&#160;            });</div><div class="line"><a name="l00133"></a><span class="lineno">  133</span>&#160;    }</div><div class="line"><a name="l00134"></a><span class="lineno">  134</span>&#160;}</div><div class="line"><a name="l00135"></a><span class="lineno">  135</span>&#160;</div><div class="line"><a name="l00146"></a><span class="lineno">  146</span>&#160;<span class="keyword">template</span> &lt;<span class="keyword">typename</span> SrcView, <span class="keyword">typename</span> DstView&gt;</div><div class="line"><a name="l00147"></a><span class="lineno"><a class="line" href="group___image_processing.html#gaeaf67a8717e170a8eacd7ca80273dd85">  147</a></span>&#160;<span class="keywordtype">void</span> <a class="code" href="group___image_processing.html#gaeaf67a8717e170a8eacd7ca80273dd85">threshold_binary</a>(</div><div class="line"><a name="l00148"></a><span class="lineno">  148</span>&#160;    SrcView <span class="keyword">const</span>&amp; src_view,</div><div class="line"><a name="l00149"></a><span class="lineno">  149</span>&#160;    DstView <span class="keyword">const</span>&amp; dst_view,</div><div class="line"><a name="l00150"></a><span class="lineno">  150</span>&#160;    <span class="keyword">typename</span> <a class="code" href="structboost_1_1gil_1_1channel__type.html">channel_type&lt;DstView&gt;::type</a> threshold_value,</div><div class="line"><a name="l00151"></a><span class="lineno">  151</span>&#160;    <a class="code" href="group___image_processing.html#gae73d8b37c737a81ffa26b0c5c62d8f0e">threshold_direction</a> direction = <a class="code" href="group___image_processing.html#ggae73d8b37c737a81ffa26b0c5c62d8f0eaaf37d08ae228a87dc6b265fd1019c97d">threshold_direction::regular</a></div><div class="line"><a name="l00152"></a><span class="lineno">  152</span>&#160;)</div><div class="line"><a name="l00153"></a><span class="lineno">  153</span>&#160;{</div><div class="line"><a name="l00154"></a><span class="lineno">  154</span>&#160;    <span class="comment">//deciding output channel type and creating functor</span></div><div class="line"><a name="l00155"></a><span class="lineno">  155</span>&#160;    <span class="keyword">using</span> result_channel_t = <span class="keyword">typename</span> <a class="code" href="structboost_1_1gil_1_1channel__type.html">channel_type&lt;DstView&gt;::type</a>;</div><div class="line"><a name="l00156"></a><span class="lineno">  156</span>&#160;</div><div class="line"><a name="l00157"></a><span class="lineno">  157</span>&#160;    result_channel_t max_value = (std::numeric_limits&lt;result_channel_t&gt;::max)();</div><div class="line"><a name="l00158"></a><span class="lineno">  158</span>&#160;    <a class="code" href="group___image_processing.html#gaeaf67a8717e170a8eacd7ca80273dd85">threshold_binary</a>(src_view, dst_view, threshold_value, max_value, direction);</div><div class="line"><a name="l00159"></a><span class="lineno">  159</span>&#160;}</div><div class="line"><a name="l00160"></a><span class="lineno">  160</span>&#160;</div><div class="line"><a name="l00172"></a><span class="lineno">  172</span>&#160;<span class="keyword">template</span> &lt;<span class="keyword">typename</span> SrcView, <span class="keyword">typename</span> DstView&gt;</div><div class="line"><a name="l00173"></a><span class="lineno"><a class="line" href="group___image_processing.html#gacbd19f2c4dc367e744d2aac412f98055">  173</a></span>&#160;<span class="keywordtype">void</span> <a class="code" href="group___image_processing.html#gacbd19f2c4dc367e744d2aac412f98055">threshold_truncate</a>(</div><div class="line"><a name="l00174"></a><span class="lineno">  174</span>&#160;    SrcView <span class="keyword">const</span>&amp; src_view,</div><div class="line"><a name="l00175"></a><span class="lineno">  175</span>&#160;    DstView <span class="keyword">const</span>&amp; dst_view,</div><div class="line"><a name="l00176"></a><span class="lineno">  176</span>&#160;    <span class="keyword">typename</span> <a class="code" href="structboost_1_1gil_1_1channel__type.html">channel_type&lt;DstView&gt;::type</a> threshold_value,</div><div class="line"><a name="l00177"></a><span class="lineno">  177</span>&#160;    <a class="code" href="group___image_processing.html#ga7b2c4d7867de63cfdc39c26d750efab0">threshold_truncate_mode</a> mode = <a class="code" href="group___image_processing.html#gga7b2c4d7867de63cfdc39c26d750efab0af0598264a691a8f62272aca0e79af374">threshold_truncate_mode::threshold</a>,</div><div class="line"><a name="l00178"></a><span class="lineno">  178</span>&#160;    <a class="code" href="group___image_processing.html#gae73d8b37c737a81ffa26b0c5c62d8f0e">threshold_direction</a> direction = <a class="code" href="group___image_processing.html#ggae73d8b37c737a81ffa26b0c5c62d8f0eaaf37d08ae228a87dc6b265fd1019c97d">threshold_direction::regular</a></div><div class="line"><a name="l00179"></a><span class="lineno">  179</span>&#160;)</div><div class="line"><a name="l00180"></a><span class="lineno">  180</span>&#160;{</div><div class="line"><a name="l00181"></a><span class="lineno">  181</span>&#160;    <span class="comment">//deciding output channel type and creating functor</span></div><div class="line"><a name="l00182"></a><span class="lineno">  182</span>&#160;    <span class="keyword">using</span> source_channel_t = <span class="keyword">typename</span> <a class="code" href="structboost_1_1gil_1_1channel__type.html">channel_type&lt;SrcView&gt;::type</a>;</div><div class="line"><a name="l00183"></a><span class="lineno">  183</span>&#160;    <span class="keyword">using</span> result_channel_t = <span class="keyword">typename</span> <a class="code" href="structboost_1_1gil_1_1channel__type.html">channel_type&lt;DstView&gt;::type</a>;</div><div class="line"><a name="l00184"></a><span class="lineno">  184</span>&#160;</div><div class="line"><a name="l00185"></a><span class="lineno">  185</span>&#160;    std::function&lt;result_channel_t(source_channel_t)&gt; threshold_logic;</div><div class="line"><a name="l00186"></a><span class="lineno">  186</span>&#160;</div><div class="line"><a name="l00187"></a><span class="lineno">  187</span>&#160;    <span class="keywordflow">if</span> (mode == <a class="code" href="group___image_processing.html#gga7b2c4d7867de63cfdc39c26d750efab0af0598264a691a8f62272aca0e79af374">threshold_truncate_mode::threshold</a>)</div><div class="line"><a name="l00188"></a><span class="lineno">  188</span>&#160;    {</div><div class="line"><a name="l00189"></a><span class="lineno">  189</span>&#160;        <span class="keywordflow">if</span> (direction == <a class="code" href="group___image_processing.html#ggae73d8b37c737a81ffa26b0c5c62d8f0eaaf37d08ae228a87dc6b265fd1019c97d">threshold_direction::regular</a>)</div><div class="line"><a name="l00190"></a><span class="lineno">  190</span>&#160;        {</div><div class="line"><a name="l00191"></a><span class="lineno">  191</span>&#160;            detail::threshold_impl&lt;source_channel_t, result_channel_t&gt;(src_view, dst_view,</div><div class="line"><a name="l00192"></a><span class="lineno">  192</span>&#160;                [threshold_value](source_channel_t px) -&gt; result_channel_t {</div><div class="line"><a name="l00193"></a><span class="lineno">  193</span>&#160;                    <span class="keywordflow">return</span> px &gt; threshold_value ? threshold_value : px;</div><div class="line"><a name="l00194"></a><span class="lineno">  194</span>&#160;                });</div><div class="line"><a name="l00195"></a><span class="lineno">  195</span>&#160;        }</div><div class="line"><a name="l00196"></a><span class="lineno">  196</span>&#160;        <span class="keywordflow">else</span></div><div class="line"><a name="l00197"></a><span class="lineno">  197</span>&#160;        {</div><div class="line"><a name="l00198"></a><span class="lineno">  198</span>&#160;            detail::threshold_impl&lt;source_channel_t, result_channel_t&gt;(src_view, dst_view,</div><div class="line"><a name="l00199"></a><span class="lineno">  199</span>&#160;                [threshold_value](source_channel_t px) -&gt; result_channel_t {</div><div class="line"><a name="l00200"></a><span class="lineno">  200</span>&#160;                    <span class="keywordflow">return</span> px &gt; threshold_value ? px : threshold_value;</div><div class="line"><a name="l00201"></a><span class="lineno">  201</span>&#160;                });</div><div class="line"><a name="l00202"></a><span class="lineno">  202</span>&#160;        }</div><div class="line"><a name="l00203"></a><span class="lineno">  203</span>&#160;    }</div><div class="line"><a name="l00204"></a><span class="lineno">  204</span>&#160;    <span class="keywordflow">else</span></div><div class="line"><a name="l00205"></a><span class="lineno">  205</span>&#160;    {</div><div class="line"><a name="l00206"></a><span class="lineno">  206</span>&#160;        <span class="keywordflow">if</span> (direction == <a class="code" href="group___image_processing.html#ggae73d8b37c737a81ffa26b0c5c62d8f0eaaf37d08ae228a87dc6b265fd1019c97d">threshold_direction::regular</a>)</div><div class="line"><a name="l00207"></a><span class="lineno">  207</span>&#160;        {</div><div class="line"><a name="l00208"></a><span class="lineno">  208</span>&#160;            detail::threshold_impl&lt;source_channel_t, result_channel_t&gt;(src_view, dst_view,</div><div class="line"><a name="l00209"></a><span class="lineno">  209</span>&#160;                [threshold_value](source_channel_t px) -&gt; result_channel_t {</div><div class="line"><a name="l00210"></a><span class="lineno">  210</span>&#160;                    <span class="keywordflow">return</span> px &gt; threshold_value ? px : 0;</div><div class="line"><a name="l00211"></a><span class="lineno">  211</span>&#160;                });</div><div class="line"><a name="l00212"></a><span class="lineno">  212</span>&#160;        }</div><div class="line"><a name="l00213"></a><span class="lineno">  213</span>&#160;        <span class="keywordflow">else</span></div><div class="line"><a name="l00214"></a><span class="lineno">  214</span>&#160;        {</div><div class="line"><a name="l00215"></a><span class="lineno">  215</span>&#160;            detail::threshold_impl&lt;source_channel_t, result_channel_t&gt;(src_view, dst_view,</div><div class="line"><a name="l00216"></a><span class="lineno">  216</span>&#160;                [threshold_value](source_channel_t px) -&gt; result_channel_t {</div><div class="line"><a name="l00217"></a><span class="lineno">  217</span>&#160;                    <span class="keywordflow">return</span> px &gt; threshold_value ? 0 : px;</div><div class="line"><a name="l00218"></a><span class="lineno">  218</span>&#160;                });</div><div class="line"><a name="l00219"></a><span class="lineno">  219</span>&#160;        }</div><div class="line"><a name="l00220"></a><span class="lineno">  220</span>&#160;    }</div><div class="line"><a name="l00221"></a><span class="lineno">  221</span>&#160;}</div><div class="line"><a name="l00222"></a><span class="lineno">  222</span>&#160;</div><div class="line"><a name="l00223"></a><span class="lineno">  223</span>&#160;<span class="keyword">namespace </span>detail{</div><div class="line"><a name="l00224"></a><span class="lineno">  224</span>&#160;</div><div class="line"><a name="l00225"></a><span class="lineno">  225</span>&#160;<span class="keyword">template</span> &lt;<span class="keyword">typename</span> SrcView, <span class="keyword">typename</span> DstView&gt;</div><div class="line"><a name="l00226"></a><span class="lineno">  226</span>&#160;<span class="keywordtype">void</span> otsu_impl(SrcView <span class="keyword">const</span>&amp; src_view, DstView <span class="keyword">const</span>&amp; dst_view, <a class="code" href="group___image_processing.html#gae73d8b37c737a81ffa26b0c5c62d8f0e">threshold_direction</a> direction)</div><div class="line"><a name="l00227"></a><span class="lineno">  227</span>&#160;{</div><div class="line"><a name="l00228"></a><span class="lineno">  228</span>&#160;    <span class="comment">//deciding output channel type and creating functor</span></div><div class="line"><a name="l00229"></a><span class="lineno">  229</span>&#160;    <span class="keyword">using</span> source_channel_t = <span class="keyword">typename</span> channel_type&lt;SrcView&gt;::type;</div><div class="line"><a name="l00230"></a><span class="lineno">  230</span>&#160;</div><div class="line"><a name="l00231"></a><span class="lineno">  231</span>&#160;    std::array&lt;std::size_t, 256&gt; histogram{};</div><div class="line"><a name="l00232"></a><span class="lineno">  232</span>&#160;    <span class="comment">//initial value of min is set to maximum possible value to compare histogram data</span></div><div class="line"><a name="l00233"></a><span class="lineno">  233</span>&#160;    <span class="comment">//initial value of max is set to minimum possible value to compare histogram data</span></div><div class="line"><a name="l00234"></a><span class="lineno">  234</span>&#160;    <span class="keyword">auto</span> min = (std::numeric_limits&lt;source_channel_t&gt;::max)(),</div><div class="line"><a name="l00235"></a><span class="lineno">  235</span>&#160;        max = (std::numeric_limits&lt;source_channel_t&gt;::min)();</div><div class="line"><a name="l00236"></a><span class="lineno">  236</span>&#160;</div><div class="line"><a name="l00237"></a><span class="lineno">  237</span>&#160;    <span class="keywordflow">if</span> (<span class="keyword">sizeof</span>(source_channel_t) &gt; 1 || std::is_signed&lt;source_channel_t&gt;::value)</div><div class="line"><a name="l00238"></a><span class="lineno">  238</span>&#160;    {</div><div class="line"><a name="l00239"></a><span class="lineno">  239</span>&#160;        <span class="comment">//iterate over the image to find the min and max pixel values</span></div><div class="line"><a name="l00240"></a><span class="lineno">  240</span>&#160;        <span class="keywordflow">for</span> (std::ptrdiff_t y = 0; y &lt; src_view.height(); y++)</div><div class="line"><a name="l00241"></a><span class="lineno">  241</span>&#160;        {</div><div class="line"><a name="l00242"></a><span class="lineno">  242</span>&#160;            <span class="keyword">typename</span> SrcView::x_iterator src_it = src_view.row_begin(y);</div><div class="line"><a name="l00243"></a><span class="lineno">  243</span>&#160;            <span class="keywordflow">for</span> (std::ptrdiff_t x = 0; x &lt; src_view.width(); x++)</div><div class="line"><a name="l00244"></a><span class="lineno">  244</span>&#160;            {</div><div class="line"><a name="l00245"></a><span class="lineno">  245</span>&#160;                <span class="keywordflow">if</span> (src_it[x] &lt; min) min = src_it[x];</div><div class="line"><a name="l00246"></a><span class="lineno">  246</span>&#160;                <span class="keywordflow">if</span> (src_it[x] &gt; min) min = src_it[x];</div><div class="line"><a name="l00247"></a><span class="lineno">  247</span>&#160;            }</div><div class="line"><a name="l00248"></a><span class="lineno">  248</span>&#160;        }</div><div class="line"><a name="l00249"></a><span class="lineno">  249</span>&#160;</div><div class="line"><a name="l00250"></a><span class="lineno">  250</span>&#160;        <span class="comment">//making histogram</span></div><div class="line"><a name="l00251"></a><span class="lineno">  251</span>&#160;        <span class="keywordflow">for</span> (std::ptrdiff_t y = 0; y &lt; src_view.height(); y++)</div><div class="line"><a name="l00252"></a><span class="lineno">  252</span>&#160;        {</div><div class="line"><a name="l00253"></a><span class="lineno">  253</span>&#160;            <span class="keyword">typename</span> SrcView::x_iterator src_it = src_view.row_begin(y);</div><div class="line"><a name="l00254"></a><span class="lineno">  254</span>&#160;</div><div class="line"><a name="l00255"></a><span class="lineno">  255</span>&#160;            <span class="keywordflow">for</span> (std::ptrdiff_t x = 0; x &lt; src_view.width(); x++)</div><div class="line"><a name="l00256"></a><span class="lineno">  256</span>&#160;            {</div><div class="line"><a name="l00257"></a><span class="lineno">  257</span>&#160;                histogram[((src_it[x] - min) * 255) / (max - min)]++;</div><div class="line"><a name="l00258"></a><span class="lineno">  258</span>&#160;            }</div><div class="line"><a name="l00259"></a><span class="lineno">  259</span>&#160;        }</div><div class="line"><a name="l00260"></a><span class="lineno">  260</span>&#160;    }</div><div class="line"><a name="l00261"></a><span class="lineno">  261</span>&#160;    <span class="keywordflow">else</span></div><div class="line"><a name="l00262"></a><span class="lineno">  262</span>&#160;    {</div><div class="line"><a name="l00263"></a><span class="lineno">  263</span>&#160;        <span class="comment">//making histogram</span></div><div class="line"><a name="l00264"></a><span class="lineno">  264</span>&#160;        <span class="keywordflow">for</span> (std::ptrdiff_t y = 0; y &lt; src_view.height(); y++)</div><div class="line"><a name="l00265"></a><span class="lineno">  265</span>&#160;        {</div><div class="line"><a name="l00266"></a><span class="lineno">  266</span>&#160;            <span class="keyword">typename</span> SrcView::x_iterator src_it = src_view.row_begin(y);</div><div class="line"><a name="l00267"></a><span class="lineno">  267</span>&#160;</div><div class="line"><a name="l00268"></a><span class="lineno">  268</span>&#160;            <span class="keywordflow">for</span> (std::ptrdiff_t x = 0; x &lt; src_view.width(); x++)</div><div class="line"><a name="l00269"></a><span class="lineno">  269</span>&#160;            {</div><div class="line"><a name="l00270"></a><span class="lineno">  270</span>&#160;                histogram[src_it[x]]++;</div><div class="line"><a name="l00271"></a><span class="lineno">  271</span>&#160;            }</div><div class="line"><a name="l00272"></a><span class="lineno">  272</span>&#160;        }</div><div class="line"><a name="l00273"></a><span class="lineno">  273</span>&#160;    }</div><div class="line"><a name="l00274"></a><span class="lineno">  274</span>&#160;</div><div class="line"><a name="l00275"></a><span class="lineno">  275</span>&#160;    <span class="comment">//histData = histogram data</span></div><div class="line"><a name="l00276"></a><span class="lineno">  276</span>&#160;    <span class="comment">//sum = total (background + foreground)</span></div><div class="line"><a name="l00277"></a><span class="lineno">  277</span>&#160;    <span class="comment">//sumB = sum background</span></div><div class="line"><a name="l00278"></a><span class="lineno">  278</span>&#160;    <span class="comment">//wB = weight background</span></div><div class="line"><a name="l00279"></a><span class="lineno">  279</span>&#160;    <span class="comment">//wf = weight foreground</span></div><div class="line"><a name="l00280"></a><span class="lineno">  280</span>&#160;    <span class="comment">//varMax = tracking the maximum known value of between class variance</span></div><div class="line"><a name="l00281"></a><span class="lineno">  281</span>&#160;    <span class="comment">//mB = mu background</span></div><div class="line"><a name="l00282"></a><span class="lineno">  282</span>&#160;    <span class="comment">//mF = mu foreground</span></div><div class="line"><a name="l00283"></a><span class="lineno">  283</span>&#160;    <span class="comment">//varBeetween = between class variance</span></div><div class="line"><a name="l00284"></a><span class="lineno">  284</span>&#160;    <span class="comment">//http://www.labbookpages.co.uk/software/imgProc/otsuThreshold.html</span></div><div class="line"><a name="l00285"></a><span class="lineno">  285</span>&#160;    <span class="comment">//https://www.ipol.im/pub/art/2016/158/</span></div><div class="line"><a name="l00286"></a><span class="lineno">  286</span>&#160;    std::ptrdiff_t total_pixel = src_view.height() * src_view.width();</div><div class="line"><a name="l00287"></a><span class="lineno">  287</span>&#160;    std::ptrdiff_t sum_total = 0, sum_back = 0;</div><div class="line"><a name="l00288"></a><span class="lineno">  288</span>&#160;    std::size_t weight_back = 0, weight_fore = 0, <a class="code" href="group___image_processing.html#gga7b2c4d7867de63cfdc39c26d750efab0af0598264a691a8f62272aca0e79af374">threshold</a> = 0;</div><div class="line"><a name="l00289"></a><span class="lineno">  289</span>&#160;    <span class="keywordtype">double</span> var_max = 0, mean_back, mean_fore, var_intra_class;</div><div class="line"><a name="l00290"></a><span class="lineno">  290</span>&#160;</div><div class="line"><a name="l00291"></a><span class="lineno">  291</span>&#160;    <span class="keywordflow">for</span> (std::size_t t = 0; t &lt; 256; t++)</div><div class="line"><a name="l00292"></a><span class="lineno">  292</span>&#160;    {</div><div class="line"><a name="l00293"></a><span class="lineno">  293</span>&#160;        sum_total += t * histogram[t];</div><div class="line"><a name="l00294"></a><span class="lineno">  294</span>&#160;    }</div><div class="line"><a name="l00295"></a><span class="lineno">  295</span>&#160;</div><div class="line"><a name="l00296"></a><span class="lineno">  296</span>&#160;    <span class="keywordflow">for</span> (<span class="keywordtype">int</span> t = 0; t &lt; 256; t++)</div><div class="line"><a name="l00297"></a><span class="lineno">  297</span>&#160;    {</div><div class="line"><a name="l00298"></a><span class="lineno">  298</span>&#160;        weight_back += histogram[t];               <span class="comment">// Weight Background</span></div><div class="line"><a name="l00299"></a><span class="lineno">  299</span>&#160;        <span class="keywordflow">if</span> (weight_back == 0) <span class="keywordflow">continue</span>;</div><div class="line"><a name="l00300"></a><span class="lineno">  300</span>&#160;</div><div class="line"><a name="l00301"></a><span class="lineno">  301</span>&#160;        weight_fore = total_pixel - weight_back;          <span class="comment">// Weight Foreground</span></div><div class="line"><a name="l00302"></a><span class="lineno">  302</span>&#160;        <span class="keywordflow">if</span> (weight_fore == 0) <span class="keywordflow">break</span>;</div><div class="line"><a name="l00303"></a><span class="lineno">  303</span>&#160;</div><div class="line"><a name="l00304"></a><span class="lineno">  304</span>&#160;        sum_back += t * histogram[t];</div><div class="line"><a name="l00305"></a><span class="lineno">  305</span>&#160;</div><div class="line"><a name="l00306"></a><span class="lineno">  306</span>&#160;        mean_back = sum_back / weight_back;            <span class="comment">// Mean Background</span></div><div class="line"><a name="l00307"></a><span class="lineno">  307</span>&#160;        mean_fore = (sum_total - sum_back) / weight_fore;    <span class="comment">// Mean Foreground</span></div><div class="line"><a name="l00308"></a><span class="lineno">  308</span>&#160;</div><div class="line"><a name="l00309"></a><span class="lineno">  309</span>&#160;        <span class="comment">// Calculate Between Class Variance</span></div><div class="line"><a name="l00310"></a><span class="lineno">  310</span>&#160;        var_intra_class = weight_back * weight_fore * (mean_back - mean_fore) * (mean_back - mean_fore);</div><div class="line"><a name="l00311"></a><span class="lineno">  311</span>&#160;</div><div class="line"><a name="l00312"></a><span class="lineno">  312</span>&#160;        <span class="comment">// Check if new maximum found</span></div><div class="line"><a name="l00313"></a><span class="lineno">  313</span>&#160;        <span class="keywordflow">if</span> (var_intra_class &gt; var_max) {</div><div class="line"><a name="l00314"></a><span class="lineno">  314</span>&#160;            var_max = var_intra_class;</div><div class="line"><a name="l00315"></a><span class="lineno">  315</span>&#160;            <a class="code" href="group___image_processing.html#gga7b2c4d7867de63cfdc39c26d750efab0af0598264a691a8f62272aca0e79af374">threshold</a> = t;</div><div class="line"><a name="l00316"></a><span class="lineno">  316</span>&#160;        }</div><div class="line"><a name="l00317"></a><span class="lineno">  317</span>&#160;    }</div><div class="line"><a name="l00318"></a><span class="lineno">  318</span>&#160;    <span class="keywordflow">if</span> (<span class="keyword">sizeof</span>(source_channel_t) &gt; 1 &amp;&amp; std::is_unsigned&lt;source_channel_t&gt;::value)</div><div class="line"><a name="l00319"></a><span class="lineno">  319</span>&#160;    {</div><div class="line"><a name="l00320"></a><span class="lineno">  320</span>&#160;        <a class="code" href="group___image_processing.html#gaeaf67a8717e170a8eacd7ca80273dd85">threshold_binary</a>(src_view, dst_view, (<a class="code" href="group___image_processing.html#gga7b2c4d7867de63cfdc39c26d750efab0af0598264a691a8f62272aca0e79af374">threshold</a> * (max - min) / 255) + min, direction);</div><div class="line"><a name="l00321"></a><span class="lineno">  321</span>&#160;    }</div><div class="line"><a name="l00322"></a><span class="lineno">  322</span>&#160;    <span class="keywordflow">else</span> {</div><div class="line"><a name="l00323"></a><span class="lineno">  323</span>&#160;        <a class="code" href="group___image_processing.html#gaeaf67a8717e170a8eacd7ca80273dd85">threshold_binary</a>(src_view, dst_view, <a class="code" href="group___image_processing.html#gga7b2c4d7867de63cfdc39c26d750efab0af0598264a691a8f62272aca0e79af374">threshold</a>, direction);</div><div class="line"><a name="l00324"></a><span class="lineno">  324</span>&#160;    }</div><div class="line"><a name="l00325"></a><span class="lineno">  325</span>&#160;}</div><div class="line"><a name="l00326"></a><span class="lineno">  326</span>&#160;} <span class="comment">//namespace detail</span></div><div class="line"><a name="l00327"></a><span class="lineno">  327</span>&#160;</div><div class="line"><a name="l00328"></a><span class="lineno">  328</span>&#160;<span class="keyword">template</span> &lt;<span class="keyword">typename</span> SrcView, <span class="keyword">typename</span> DstView&gt;</div><div class="line"><a name="l00329"></a><span class="lineno">  329</span>&#160;<span class="keywordtype">void</span> threshold_optimal</div><div class="line"><a name="l00330"></a><span class="lineno">  330</span>&#160;(</div><div class="line"><a name="l00331"></a><span class="lineno">  331</span>&#160;    SrcView <span class="keyword">const</span>&amp; src_view,</div><div class="line"><a name="l00332"></a><span class="lineno">  332</span>&#160;    DstView <span class="keyword">const</span>&amp; dst_view,</div><div class="line"><a name="l00333"></a><span class="lineno">  333</span>&#160;    <a class="code" href="group___image_processing.html#ga62185ec305fdb480a227c159b9fa5e84">threshold_optimal_value</a> mode = <a class="code" href="group___image_processing.html#gga62185ec305fdb480a227c159b9fa5e84a3d734c6df06af2a3ac4e82483c51c455">threshold_optimal_value::otsu</a>,</div><div class="line"><a name="l00334"></a><span class="lineno">  334</span>&#160;    <a class="code" href="group___image_processing.html#gae73d8b37c737a81ffa26b0c5c62d8f0e">threshold_direction</a> direction = <a class="code" href="group___image_processing.html#ggae73d8b37c737a81ffa26b0c5c62d8f0eaaf37d08ae228a87dc6b265fd1019c97d">threshold_direction::regular</a></div><div class="line"><a name="l00335"></a><span class="lineno">  335</span>&#160;)</div><div class="line"><a name="l00336"></a><span class="lineno">  336</span>&#160;{</div><div class="line"><a name="l00337"></a><span class="lineno">  337</span>&#160;    <span class="keywordflow">if</span> (mode == <a class="code" href="group___image_processing.html#gga62185ec305fdb480a227c159b9fa5e84a3d734c6df06af2a3ac4e82483c51c455">threshold_optimal_value::otsu</a>)</div><div class="line"><a name="l00338"></a><span class="lineno">  338</span>&#160;    {</div><div class="line"><a name="l00339"></a><span class="lineno">  339</span>&#160;        <span class="keywordflow">for</span> (std::size_t i = 0; i &lt; src_view.num_channels(); i++)</div><div class="line"><a name="l00340"></a><span class="lineno">  340</span>&#160;        {</div><div class="line"><a name="l00341"></a><span class="lineno">  341</span>&#160;            detail::otsu_impl</div><div class="line"><a name="l00342"></a><span class="lineno">  342</span>&#160;                (nth_channel_view(src_view, i), nth_channel_view(dst_view, i), direction);</div><div class="line"><a name="l00343"></a><span class="lineno">  343</span>&#160;        }</div><div class="line"><a name="l00344"></a><span class="lineno">  344</span>&#160;    }</div><div class="line"><a name="l00345"></a><span class="lineno">  345</span>&#160;}</div><div class="line"><a name="l00346"></a><span class="lineno">  346</span>&#160;</div><div class="line"><a name="l00347"></a><span class="lineno">  347</span>&#160;<span class="keyword">namespace </span>detail {</div><div class="line"><a name="l00348"></a><span class="lineno">  348</span>&#160;</div><div class="line"><a name="l00349"></a><span class="lineno">  349</span>&#160;<span class="keyword">template</span></div><div class="line"><a name="l00350"></a><span class="lineno">  350</span>&#160;&lt;</div><div class="line"><a name="l00351"></a><span class="lineno">  351</span>&#160;    <span class="keyword">typename</span> SourceChannelT,</div><div class="line"><a name="l00352"></a><span class="lineno">  352</span>&#160;    <span class="keyword">typename</span> ResultChannelT,</div><div class="line"><a name="l00353"></a><span class="lineno">  353</span>&#160;    <span class="keyword">typename</span> SrcView,</div><div class="line"><a name="l00354"></a><span class="lineno">  354</span>&#160;    <span class="keyword">typename</span> DstView,</div><div class="line"><a name="l00355"></a><span class="lineno">  355</span>&#160;    <span class="keyword">typename</span> Operator</div><div class="line"><a name="l00356"></a><span class="lineno">  356</span>&#160;&gt;</div><div class="line"><a name="l00357"></a><span class="lineno">  357</span>&#160;<span class="keywordtype">void</span> adaptive_impl</div><div class="line"><a name="l00358"></a><span class="lineno">  358</span>&#160;(</div><div class="line"><a name="l00359"></a><span class="lineno">  359</span>&#160;    SrcView <span class="keyword">const</span>&amp; src_view,</div><div class="line"><a name="l00360"></a><span class="lineno">  360</span>&#160;    SrcView <span class="keyword">const</span>&amp; convolved_view,</div><div class="line"><a name="l00361"></a><span class="lineno">  361</span>&#160;    DstView <span class="keyword">const</span>&amp; dst_view,</div><div class="line"><a name="l00362"></a><span class="lineno">  362</span>&#160;    Operator <span class="keyword">const</span>&amp; threshold_op</div><div class="line"><a name="l00363"></a><span class="lineno">  363</span>&#160;)</div><div class="line"><a name="l00364"></a><span class="lineno">  364</span>&#160;{</div><div class="line"><a name="l00365"></a><span class="lineno">  365</span>&#160;    <span class="comment">//template argument validation</span></div><div class="line"><a name="l00366"></a><span class="lineno">  366</span>&#160;    gil_function_requires&lt;ImageViewConcept&lt;SrcView&gt;&gt;();</div><div class="line"><a name="l00367"></a><span class="lineno">  367</span>&#160;    gil_function_requires&lt;MutableImageViewConcept&lt;DstView&gt;&gt;();</div><div class="line"><a name="l00368"></a><span class="lineno">  368</span>&#160;</div><div class="line"><a name="l00369"></a><span class="lineno">  369</span>&#160;    static_assert(color_spaces_are_compatible</div><div class="line"><a name="l00370"></a><span class="lineno">  370</span>&#160;    &lt;</div><div class="line"><a name="l00371"></a><span class="lineno">  371</span>&#160;        <span class="keyword">typename</span> color_space_type&lt;SrcView&gt;::type,</div><div class="line"><a name="l00372"></a><span class="lineno">  372</span>&#160;        <span class="keyword">typename</span> color_space_type&lt;DstView&gt;::type</div><div class="line"><a name="l00373"></a><span class="lineno">  373</span>&#160;    &gt;::value, <span class="stringliteral">&quot;Source and destination views must have pixels with the same color space&quot;</span>);</div><div class="line"><a name="l00374"></a><span class="lineno">  374</span>&#160;</div><div class="line"><a name="l00375"></a><span class="lineno">  375</span>&#160;    <span class="comment">//iterate over the image chaecking each pixel value for the threshold</span></div><div class="line"><a name="l00376"></a><span class="lineno">  376</span>&#160;    <span class="keywordflow">for</span> (std::ptrdiff_t y = 0; y &lt; src_view.height(); y++)</div><div class="line"><a name="l00377"></a><span class="lineno">  377</span>&#160;    {</div><div class="line"><a name="l00378"></a><span class="lineno">  378</span>&#160;        <span class="keyword">typename</span> SrcView::x_iterator src_it = src_view.row_begin(y);</div><div class="line"><a name="l00379"></a><span class="lineno">  379</span>&#160;        <span class="keyword">typename</span> SrcView::x_iterator convolved_it = convolved_view.row_begin(y);</div><div class="line"><a name="l00380"></a><span class="lineno">  380</span>&#160;        <span class="keyword">typename</span> DstView::x_iterator dst_it = dst_view.row_begin(y);</div><div class="line"><a name="l00381"></a><span class="lineno">  381</span>&#160;</div><div class="line"><a name="l00382"></a><span class="lineno">  382</span>&#160;        <span class="keywordflow">for</span> (std::ptrdiff_t x = 0; x &lt; src_view.width(); x++)</div><div class="line"><a name="l00383"></a><span class="lineno">  383</span>&#160;        {</div><div class="line"><a name="l00384"></a><span class="lineno">  384</span>&#160;            static_transform(src_it[x], convolved_it[x], dst_it[x], threshold_op);</div><div class="line"><a name="l00385"></a><span class="lineno">  385</span>&#160;        }</div><div class="line"><a name="l00386"></a><span class="lineno">  386</span>&#160;    }</div><div class="line"><a name="l00387"></a><span class="lineno">  387</span>&#160;}</div><div class="line"><a name="l00388"></a><span class="lineno">  388</span>&#160;} <span class="comment">//namespace boost::gil::detail</span></div><div class="line"><a name="l00389"></a><span class="lineno">  389</span>&#160;</div><div class="line"><a name="l00390"></a><span class="lineno">  390</span>&#160;<span class="keyword">template</span> &lt;<span class="keyword">typename</span> SrcView, <span class="keyword">typename</span> DstView&gt;</div><div class="line"><a name="l00391"></a><span class="lineno">  391</span>&#160;<span class="keywordtype">void</span> threshold_adaptive</div><div class="line"><a name="l00392"></a><span class="lineno">  392</span>&#160;(</div><div class="line"><a name="l00393"></a><span class="lineno">  393</span>&#160;    SrcView <span class="keyword">const</span>&amp; src_view,</div><div class="line"><a name="l00394"></a><span class="lineno">  394</span>&#160;    DstView <span class="keyword">const</span>&amp; dst_view,</div><div class="line"><a name="l00395"></a><span class="lineno">  395</span>&#160;    <span class="keyword">typename</span> channel_type&lt;DstView&gt;::type max_value,</div><div class="line"><a name="l00396"></a><span class="lineno">  396</span>&#160;    std::size_t kernel_size,</div><div class="line"><a name="l00397"></a><span class="lineno">  397</span>&#160;    threshold_adaptive_method method = threshold_adaptive_method::mean,</div><div class="line"><a name="l00398"></a><span class="lineno">  398</span>&#160;    <a class="code" href="group___image_processing.html#gae73d8b37c737a81ffa26b0c5c62d8f0e">threshold_direction</a> direction = <a class="code" href="group___image_processing.html#ggae73d8b37c737a81ffa26b0c5c62d8f0eaaf37d08ae228a87dc6b265fd1019c97d">threshold_direction::regular</a>,</div><div class="line"><a name="l00399"></a><span class="lineno">  399</span>&#160;    <span class="keyword">typename</span> channel_type&lt;DstView&gt;::type constant = 0</div><div class="line"><a name="l00400"></a><span class="lineno">  400</span>&#160;)</div><div class="line"><a name="l00401"></a><span class="lineno">  401</span>&#160;{</div><div class="line"><a name="l00402"></a><span class="lineno">  402</span>&#160;    BOOST_ASSERT_MSG((kernel_size % 2 != 0), <span class="stringliteral">&quot;Kernel size must be an odd number&quot;</span>);</div><div class="line"><a name="l00403"></a><span class="lineno">  403</span>&#160;</div><div class="line"><a name="l00404"></a><span class="lineno">  404</span>&#160;    <span class="keyword">typedef</span> <span class="keyword">typename</span> channel_type&lt;SrcView&gt;::type source_channel_t;</div><div class="line"><a name="l00405"></a><span class="lineno">  405</span>&#160;    <span class="keyword">typedef</span> <span class="keyword">typename</span> channel_type&lt;DstView&gt;::type result_channel_t;</div><div class="line"><a name="l00406"></a><span class="lineno">  406</span>&#160;</div><div class="line"><a name="l00407"></a><span class="lineno">  407</span>&#160;    image&lt;typename SrcView::value_type&gt; temp_img(src_view.width(), src_view.height());</div><div class="line"><a name="l00408"></a><span class="lineno">  408</span>&#160;    <span class="keyword">typename</span> image&lt;typename SrcView::value_type&gt;::view_t temp_view = <a class="code" href="group___image_model.html#ga633557dbbff2d21c784b73412b47bb38">view</a>(temp_img);</div><div class="line"><a name="l00409"></a><span class="lineno">  409</span>&#160;    SrcView temp_conv(temp_view);</div><div class="line"><a name="l00410"></a><span class="lineno">  410</span>&#160;</div><div class="line"><a name="l00411"></a><span class="lineno">  411</span>&#160;    <span class="keywordflow">if</span> (method == threshold_adaptive_method::mean)</div><div class="line"><a name="l00412"></a><span class="lineno">  412</span>&#160;    {</div><div class="line"><a name="l00413"></a><span class="lineno">  413</span>&#160;        std::vector&lt;float&gt; mean_kernel_values(kernel_size, 1.0f/kernel_size);</div><div class="line"><a name="l00414"></a><span class="lineno">  414</span>&#160;        kernel_1d&lt;float&gt; kernel(mean_kernel_values.begin(), kernel_size, kernel_size/2);</div><div class="line"><a name="l00415"></a><span class="lineno">  415</span>&#160;</div><div class="line"><a name="l00416"></a><span class="lineno">  416</span>&#160;        detail::convolve_1d</div><div class="line"><a name="l00417"></a><span class="lineno">  417</span>&#160;        &lt;</div><div class="line"><a name="l00418"></a><span class="lineno">  418</span>&#160;            pixel&lt;float, typename SrcView::value_type::layout_t&gt;</div><div class="line"><a name="l00419"></a><span class="lineno">  419</span>&#160;        &gt;(src_view, kernel, temp_view);</div><div class="line"><a name="l00420"></a><span class="lineno">  420</span>&#160;    }</div><div class="line"><a name="l00421"></a><span class="lineno">  421</span>&#160;    <span class="keywordflow">else</span> <span class="keywordflow">if</span> (method == threshold_adaptive_method::gaussian)</div><div class="line"><a name="l00422"></a><span class="lineno">  422</span>&#160;    {</div><div class="line"><a name="l00423"></a><span class="lineno">  423</span>&#160;        detail::kernel_2d&lt;float&gt; kernel = <a class="code" href="group___image_processing_math.html#gac1aaebf1673d8b0f087ed851b5b7a47d">generate_gaussian_kernel</a>(kernel_size, 1.0);</div><div class="line"><a name="l00424"></a><span class="lineno">  424</span>&#160;        convolve_2d(src_view, kernel, temp_view);</div><div class="line"><a name="l00425"></a><span class="lineno">  425</span>&#160;    }</div><div class="line"><a name="l00426"></a><span class="lineno">  426</span>&#160;</div><div class="line"><a name="l00427"></a><span class="lineno">  427</span>&#160;    <span class="keywordflow">if</span> (direction == <a class="code" href="group___image_processing.html#ggae73d8b37c737a81ffa26b0c5c62d8f0eaaf37d08ae228a87dc6b265fd1019c97d">threshold_direction::regular</a>)</div><div class="line"><a name="l00428"></a><span class="lineno">  428</span>&#160;    {</div><div class="line"><a name="l00429"></a><span class="lineno">  429</span>&#160;        detail::adaptive_impl&lt;source_channel_t, result_channel_t&gt;(src_view, temp_conv, dst_view,</div><div class="line"><a name="l00430"></a><span class="lineno">  430</span>&#160;            [max_value, constant](source_channel_t px, source_channel_t threshold) -&gt; result_channel_t</div><div class="line"><a name="l00431"></a><span class="lineno">  431</span>&#160;        { <span class="keywordflow">return</span> px &gt; (<a class="code" href="group___image_processing.html#gga7b2c4d7867de63cfdc39c26d750efab0af0598264a691a8f62272aca0e79af374">threshold</a> - constant) ? max_value : 0; });</div><div class="line"><a name="l00432"></a><span class="lineno">  432</span>&#160;    }</div><div class="line"><a name="l00433"></a><span class="lineno">  433</span>&#160;    <span class="keywordflow">else</span></div><div class="line"><a name="l00434"></a><span class="lineno">  434</span>&#160;    {</div><div class="line"><a name="l00435"></a><span class="lineno">  435</span>&#160;        detail::adaptive_impl&lt;source_channel_t, result_channel_t&gt;(src_view, temp_conv, dst_view,</div><div class="line"><a name="l00436"></a><span class="lineno">  436</span>&#160;            [max_value, constant](source_channel_t px, source_channel_t threshold) -&gt; result_channel_t</div><div class="line"><a name="l00437"></a><span class="lineno">  437</span>&#160;        { <span class="keywordflow">return</span> px &gt; (<a class="code" href="group___image_processing.html#gga7b2c4d7867de63cfdc39c26d750efab0af0598264a691a8f62272aca0e79af374">threshold</a> - constant) ? 0 : max_value; });</div><div class="line"><a name="l00438"></a><span class="lineno">  438</span>&#160;    }</div><div class="line"><a name="l00439"></a><span class="lineno">  439</span>&#160;}</div><div class="line"><a name="l00440"></a><span class="lineno">  440</span>&#160;</div><div class="line"><a name="l00441"></a><span class="lineno">  441</span>&#160;<span class="keyword">template</span> &lt;<span class="keyword">typename</span> SrcView, <span class="keyword">typename</span> DstView&gt;</div><div class="line"><a name="l00442"></a><span class="lineno">  442</span>&#160;<span class="keywordtype">void</span> threshold_adaptive</div><div class="line"><a name="l00443"></a><span class="lineno">  443</span>&#160;(</div><div class="line"><a name="l00444"></a><span class="lineno">  444</span>&#160;    SrcView <span class="keyword">const</span>&amp; src_view,</div><div class="line"><a name="l00445"></a><span class="lineno">  445</span>&#160;    DstView <span class="keyword">const</span>&amp; dst_view,</div><div class="line"><a name="l00446"></a><span class="lineno">  446</span>&#160;    std::size_t kernel_size,</div><div class="line"><a name="l00447"></a><span class="lineno">  447</span>&#160;    threshold_adaptive_method method = threshold_adaptive_method::mean,</div><div class="line"><a name="l00448"></a><span class="lineno">  448</span>&#160;    <a class="code" href="group___image_processing.html#gae73d8b37c737a81ffa26b0c5c62d8f0e">threshold_direction</a> direction = <a class="code" href="group___image_processing.html#ggae73d8b37c737a81ffa26b0c5c62d8f0eaaf37d08ae228a87dc6b265fd1019c97d">threshold_direction::regular</a>,</div><div class="line"><a name="l00449"></a><span class="lineno">  449</span>&#160;    <span class="keywordtype">int</span> constant = 0</div><div class="line"><a name="l00450"></a><span class="lineno">  450</span>&#160;)</div><div class="line"><a name="l00451"></a><span class="lineno">  451</span>&#160;{</div><div class="line"><a name="l00452"></a><span class="lineno">  452</span>&#160;    <span class="comment">//deciding output channel type and creating functor</span></div><div class="line"><a name="l00453"></a><span class="lineno">  453</span>&#160;    <span class="keyword">typedef</span> <span class="keyword">typename</span> channel_type&lt;DstView&gt;::type result_channel_t;</div><div class="line"><a name="l00454"></a><span class="lineno">  454</span>&#160;</div><div class="line"><a name="l00455"></a><span class="lineno">  455</span>&#160;    result_channel_t max_value = (std::numeric_limits&lt;result_channel_t&gt;::max)();</div><div class="line"><a name="l00456"></a><span class="lineno">  456</span>&#160;</div><div class="line"><a name="l00457"></a><span class="lineno">  457</span>&#160;    threshold_adaptive(src_view, dst_view, max_value, kernel_size, method, direction, constant);</div><div class="line"><a name="l00458"></a><span class="lineno">  458</span>&#160;}</div><div class="line"><a name="l00459"></a><span class="lineno">  459</span>&#160;</div><div class="line"><a name="l00461"></a><span class="lineno">  461</span>&#160;</div><div class="line"><a name="l00462"></a><span class="lineno">  462</span>&#160;}} <span class="comment">//namespace boost::gil</span></div><div class="line"><a name="l00463"></a><span class="lineno">  463</span>&#160;</div><div class="line"><a name="l00464"></a><span class="lineno">  464</span>&#160;<span class="preprocessor">#endif //BOOST_GIL_IMAGE_PROCESSING_THRESHOLD_HPP</span></div><div class="ttc" id="group___image_processing_html_gaeaf67a8717e170a8eacd7ca80273dd85"><div class="ttname"><a href="group___image_processing.html#gaeaf67a8717e170a8eacd7ca80273dd85">boost::gil::threshold_binary</a></div><div class="ttdeci">void threshold_binary(SrcView const &amp;src_view, DstView const &amp;dst_view, typename channel_type&lt; DstView &gt;::type threshold_value, threshold_direction direction=threshold_direction::regular)</div><div class="ttdoc">Applies fixed threshold to each pixel of image view. Performs image binarization by thresholding chan...</div><div class="ttdef"><b>Definition:</b> threshold.hpp:147</div></div>
  51 <div class="ttc" id="group___image_processing_html_gga7b2c4d7867de63cfdc39c26d750efab0af0598264a691a8f62272aca0e79af374"><div class="ttname"><a href="group___image_processing.html#gga7b2c4d7867de63cfdc39c26d750efab0af0598264a691a8f62272aca0e79af374">boost::gil::threshold_truncate_mode::threshold</a></div></div>
  52 <div class="ttc" id="group___image_processing_html_ga7b2c4d7867de63cfdc39c26d750efab0"><div class="ttname"><a href="group___image_processing.html#ga7b2c4d7867de63cfdc39c26d750efab0">boost::gil::threshold_truncate_mode</a></div><div class="ttdeci">threshold_truncate_mode</div><div class="ttdoc">TODO.</div><div class="ttdef"><b>Definition:</b> threshold.hpp:84</div></div>
  53 <div class="ttc" id="group___image_processing_html_gga7b2c4d7867de63cfdc39c26d750efab0ad02c4c4cde7ae76252540d116a40f23a"><div class="ttname"><a href="group___image_processing.html#gga7b2c4d7867de63cfdc39c26d750efab0ad02c4c4cde7ae76252540d116a40f23a">boost::gil::threshold_truncate_mode::zero</a></div></div>
  54 <div class="ttc" id="group___image_processing_html_gae73d8b37c737a81ffa26b0c5c62d8f0e"><div class="ttname"><a href="group___image_processing.html#gae73d8b37c737a81ffa26b0c5c62d8f0e">boost::gil::threshold_direction</a></div><div class="ttdeci">threshold_direction</div><div class="ttdef"><b>Definition:</b> threshold.hpp:69</div></div>
  55 <div class="ttc" id="group___image_processing_html_ga62185ec305fdb480a227c159b9fa5e84"><div class="ttname"><a href="group___image_processing.html#ga62185ec305fdb480a227c159b9fa5e84">boost::gil::threshold_optimal_value</a></div><div class="ttdeci">threshold_optimal_value</div><div class="ttdoc">Method of optimal threshold value calculation.</div><div class="ttdef"><b>Definition:</b> threshold.hpp:77</div></div>
  56 <div class="ttc" id="group___image_processing_html_ggae73d8b37c737a81ffa26b0c5c62d8f0eaa91c78e040f7b9d158f381e197f8beb4"><div class="ttname"><a href="group___image_processing.html#ggae73d8b37c737a81ffa26b0c5c62d8f0eaa91c78e040f7b9d158f381e197f8beb4">boost::gil::threshold_direction::inverse</a></div><div class="ttdoc">Consider values less than or equal to threshold value.</div></div>
  57 <div class="ttc" id="structboost_1_1gil_1_1channel__type_html"><div class="ttname"><a href="structboost_1_1gil_1_1channel__type.html">boost::gil::channel_type</a></div><div class="ttdef"><b>Definition:</b> color_convert.hpp:31</div></div>
  58 <div class="ttc" id="group___image_model_html_ga633557dbbff2d21c784b73412b47bb38"><div class="ttname"><a href="group___image_model.html#ga633557dbbff2d21c784b73412b47bb38">boost::gil::view</a></div><div class="ttdeci">const image&lt; Pixel, IsPlanar, Alloc &gt;::view_t &amp; view(image&lt; Pixel, IsPlanar, Alloc &gt; &amp;img)</div><div class="ttdoc">Returns the non-constant-pixel view of an image.</div><div class="ttdef"><b>Definition:</b> image.hpp:443</div></div>
  59 <div class="ttc" id="group___image_processing_html_gga62185ec305fdb480a227c159b9fa5e84a3d734c6df06af2a3ac4e82483c51c455"><div class="ttname"><a href="group___image_processing.html#gga62185ec305fdb480a227c159b9fa5e84a3d734c6df06af2a3ac4e82483c51c455">boost::gil::threshold_optimal_value::otsu</a></div></div>
  60 <div class="ttc" id="group___image_processing_html_gacbd19f2c4dc367e744d2aac412f98055"><div class="ttname"><a href="group___image_processing.html#gacbd19f2c4dc367e744d2aac412f98055">boost::gil::threshold_truncate</a></div><div class="ttdeci">void threshold_truncate(SrcView const &amp;src_view, DstView const &amp;dst_view, typename channel_type&lt; DstView &gt;::type threshold_value, threshold_truncate_mode mode=threshold_truncate_mode::threshold, threshold_direction direction=threshold_direction::regular)</div><div class="ttdoc">Applies truncating threshold to each pixel of image view. Takes an image view and performes truncatin...</div><div class="ttdef"><b>Definition:</b> threshold.hpp:173</div></div>
  61 <div class="ttc" id="group___image_processing_html_ggae73d8b37c737a81ffa26b0c5c62d8f0eaaf37d08ae228a87dc6b265fd1019c97d"><div class="ttname"><a href="group___image_processing.html#ggae73d8b37c737a81ffa26b0c5c62d8f0eaaf37d08ae228a87dc6b265fd1019c97d">boost::gil::threshold_direction::regular</a></div><div class="ttdoc">Consider values greater than threshold value.</div></div>
  62 <div class="ttc" id="group___image_processing_math_html_gac1aaebf1673d8b0f087ed851b5b7a47d"><div class="ttname"><a href="group___image_processing_math.html#gac1aaebf1673d8b0f087ed851b5b7a47d">boost::gil::generate_gaussian_kernel</a></div><div class="ttdeci">detail::kernel_2d&lt; T, Allocator &gt; generate_gaussian_kernel(std::size_t side_length, double sigma)</div><div class="ttdoc">Generate Gaussian kernelFills supplied view with values taken from Gaussian distribution....</div><div class="ttdef"><b>Definition:</b> numeric.hpp:120</div></div>
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