ne"><a name="l00065"></a><span class="lineno"><a class="line" href="structboost_1_1gil_1_1detail_1_1rgb__to__luminance__fn.html">   65</a></span>&#160;<span class="keyword">struct </span><a class="code" href="structboost_1_1gil_1_1detail_1_1rgb__to__luminance__fn.html">rgb_to_luminance_fn</a> {</div><div class="line"><a name="l00066"></a><span class="lineno">   66</span>&#160;    GrayChannelValue operator()(<span class="keyword">const</span> RedChannel&amp; red, <span class="keyword">const</span> GreenChann