* .3 + green * .59 + blue * .11 + .5">rgb_to_luminance_fn</a>&lt;uint8_t,uint8_t,uint8_t, GrayChannelValue&gt; {
<a name="l00083"></a>00083     GrayChannelValue operator()(uint8_t red, uint8_t green, uint8_t blue)<span class="keyword"> const </span>{
<a name="l00084"></a>00084         <span class="keywordflow">return</span> channel_convert&lt;GrayChannelValue&gt;(uint8_t(
<a name="l00085"></a>00085             ((uint32_t(red  )*4915 + uint32_t(green)*9667 + uint32_t(blue )*1802) + 8192) &gt;&gt; 14));
<a na