擅长:python、mysql、java
<p>最简单,但不控制每个通道的贡献量(<code>color_im</code>是一个numpy数组):</p>
<pre><code>gray_im = color_im.mean(axis=-1)
</code></pre>
<p>重量:</p>
<pre><code>gray_im = color_im[...,0]*R_weight + color_im[...,1]*G_weight + color_im[...,2]*B_weight # assumes RGB ordering of channels
</code></pre>
<p>加权版本可以等效地重写为:</p>
<pre><code>gray_im = (color_im * np.array([R_weight, G_weight, B_weight])).sum(axis=-1)
</code></pre>