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📁 数字图象处理入门,非常好的书！！！！推荐！
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<p style='margin:0cm;margin-bottom:.0001pt;text-align:justify;text-justify:
inter-ideograph;line-height:18.0pt'><span lang=ZH-CN style='font-size:10.5pt'>你大概已经明白了，当一幅图中每个象素赋予不同的</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>RGB</span><span
lang=ZH-CN style='font-size:10.5pt'>值时，能呈现出五彩缤纷的颜色了，这样就形成了彩色图。的确是这样的，但实际上的做法还有些差别。</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'><o:p></o:p></span></p>

<p style='margin:0cm;margin-bottom:.0001pt;text-align:justify;text-justify:
inter-ideograph;line-height:18.0pt'><span lang=ZH-CN style='font-size:10.5pt'>让我们来看看下面的例子。</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'><o:p></o:p></span></p>

<p style='margin:0cm;margin-bottom:.0001pt;text-align:justify;text-justify:
inter-ideograph;line-height:18.0pt'><span lang=ZH-CN style='font-size:10.5pt'>有一个长宽各为</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>200</span><span
lang=ZH-CN style='font-size:10.5pt'>个象素，颜色数为</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>16</span><span lang=ZH-CN style='font-size:10.5pt'>色的彩色图，每一个象素都用</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>R</span><span
lang=ZH-CN style='font-size:10.5pt'>、</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>G</span><span lang=ZH-CN style='font-size:10.5pt'>、</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>B</span><span
lang=ZH-CN style='font-size:10.5pt'>三个分量表示。因为每个分量有</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>256</span><span
lang=ZH-CN style='font-size:10.5pt'>个级别，要用</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>8</span><span lang=ZH-CN style='font-size:10.5pt'>位</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>(bit)</span><span
lang=ZH-CN style='font-size:10.5pt'>，即一个字节</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>(byte)</span><span lang=ZH-CN style='font-size:
10.5pt'>来表示，所以每个象素需要用</span><span style='font-size:10.5pt;font-family:"Times New Roman"'>3</span><span
lang=ZH-CN style='font-size:10.5pt'>个字节。整个图象要用</span><span style='font-size:
10.5pt;font-family:"Times New Roman"'>200×200×3</span><span lang=ZH-CN
style='font-size:10.5pt'>，约</span><span style='font-size:10.5pt;font-family:
"Times New Roman"'>120k</span><span lang=ZH-CN style='font-size:10.5pt'>字节，可不是一个小数目呀！如果我们用下面的方法，就能省的多。</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'><o:p></o:p></span></p>

<p style='margin:0cm;margin-bottom:.0001pt;text-align:justify;text-justify:
inter-ideograph;line-height:18.0pt'><span lang=ZH-CN style='font-size:10.5pt'>因为是一个</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>16</span><span
lang=ZH-CN style='font-size:10.5pt'>色图，也就是说这幅图中最多只有</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>16</span><span
lang=ZH-CN style='font-size:10.5pt'>种颜色，我们可以用一个表：表中的每一行记录一种颜色的</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>R</span><span
lang=ZH-CN style='font-size:10.5pt'>、</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>G</span><span lang=ZH-CN style='font-size:10.5pt'>、</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>B</span><span
lang=ZH-CN style='font-size:10.5pt'>值。这样当我们表示一个象素的颜色时，只需要指出该颜色是在第几行，即该颜色在表中的索引值。举个例子，如果表的第</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>0</span><span
lang=ZH-CN style='font-size:10.5pt'>行为</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>255</span><span lang=ZH-CN style='font-size:
10.5pt'>，</span><span style='font-size:10.5pt;font-family:"Times New Roman"'>0</span><span
lang=ZH-CN style='font-size:10.5pt'>，</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>0(</span><span lang=ZH-CN style='font-size:10.5pt'>红色</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>)</span><span
lang=ZH-CN style='font-size:10.5pt'>，那么当某个象素为红色时，只需要标明</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>0</span><span
lang=ZH-CN style='font-size:10.5pt'>即可。</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'><o:p></o:p></span></p>

<p style='margin:0cm;margin-bottom:.0001pt;text-align:justify;text-justify:
inter-ideograph;line-height:18.0pt'><span lang=ZH-CN style='font-size:10.5pt'>让我们再来计算一下：</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>16</span><span
lang=ZH-CN style='font-size:10.5pt'>种状态可以用</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>4</span><span lang=ZH-CN style='font-size:10.5pt'>位</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>(bit)</span><span
lang=ZH-CN style='font-size:10.5pt'>表示，所以一个象素要用半个字节。整个图象要用</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>200×200×0.5</span><span
lang=ZH-CN style='font-size:10.5pt'>，约</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>20k</span><span lang=ZH-CN style='font-size:
10.5pt'>字节，再加上表占用的字节为</span><span style='font-size:10.5pt;font-family:"Times New Roman"'>3×16=48</span><span
lang=ZH-CN style='font-size:10.5pt'>字节</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>.</span><span lang=ZH-CN style='font-size:10.5pt'>整个占用的字节数约为前面的</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>1/6</span><span
lang=ZH-CN style='font-size:10.5pt'>，省很多吧？</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'><o:p></o:p></span></p>

<p style='margin:0cm;margin-bottom:.0001pt;text-align:justify;text-justify:
inter-ideograph;line-height:18.0pt'><span lang=ZH-CN style='font-size:10.5pt'>这张</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>R</span><span
lang=ZH-CN style='font-size:10.5pt'>、</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>G</span><span lang=ZH-CN style='font-size:10.5pt'>、</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>B</span><span
lang=ZH-CN style='font-size:10.5pt'>的表，就是我们常说的调色板</span><span style='font-size:
10.5pt;font-family:"Times New Roman"'>(Palette)</span><span lang=ZH-CN
style='font-size:10.5pt'>，另一种叫法是颜色查找表</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>LUT(Look Up Table)</span><span lang=ZH-CN
style='font-size:10.5pt'>，似乎更确切一些。</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>Windows</span><span lang=ZH-CN style='font-size:
10.5pt'>位图中便用到了调色板技术。其实不光是</span><span style='font-size:10.5pt;font-family:
"Times New Roman"'>Windows</span><span lang=ZH-CN style='font-size:10.5pt'>位图，许多图象文件格式如</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>pcx</span><span
lang=ZH-CN style='font-size:10.5pt'>、</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>tif</span><span lang=ZH-CN style='font-size:
10.5pt'>、</span><span style='font-size:10.5pt;font-family:"Times New Roman"'>gif</span><span
lang=ZH-CN style='font-size:10.5pt'>等都用到了。所以很好地掌握调色板的概念是十分有用的。</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'><o:p></o:p></span></p>

<p style='margin:0cm;margin-bottom:.0001pt;text-align:justify;text-justify:
inter-ideograph;line-height:18.0pt'><span lang=ZH-CN style='font-size:10.5pt'>有一种图，它的颜色数高达</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>256×256×256</span><span
lang=ZH-CN style='font-size:10.5pt'>种，也就是说包含我们上述提到的</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>R</span><span
lang=ZH-CN style='font-size:10.5pt'>、</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>G</span><span lang=ZH-CN style='font-size:10.5pt'>、</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>B</span><span
lang=ZH-CN style='font-size:10.5pt'>颜色表示方法中所有的颜色，这种图叫做真彩色图</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>(true color)</span><span
lang=ZH-CN style='font-size:10.5pt'>。真彩色图并不是说一幅图包含了所有的颜色，而是说它具有显示所有颜色的能力，即最多可以包含所有的颜色。表示真彩色图时，每个象素直接用</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>R</span><span
lang=ZH-CN style='font-size:10.5pt'>、</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>G</span><span lang=ZH-CN style='font-size:10.5pt'>、</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>B</span><span
lang=ZH-CN style='font-size:10.5pt'>三个分量字节表示，而不采用调色板技术。原因很明显：如果用调色板，表示一个象素也要用</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>24</span><span
lang=ZH-CN style='font-size:10.5pt'>位，这是因为每种颜色的索引要用</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>24</span><span
lang=ZH-CN style='font-size:10.5pt'>位</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>(</span><span lang=ZH-CN style='font-size:10.5pt'>因为总共有</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>2<sup>24</sup></span><span
lang=ZH-CN style='font-size:10.5pt'>种颜色，即调色板有</span><span style='font-size:
10.5pt;font-family:"Times New Roman"'>2<sup>24</sup></span><span lang=ZH-CN
style='font-size:10.5pt'>行</span><span style='font-size:10.5pt;font-family:
"Times New Roman"'>)</span><span lang=ZH-CN style='font-size:10.5pt'>，和直接用</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>R</span><span
lang=ZH-CN style='font-size:10.5pt'>，</span><span style='font-size:10.5pt;
font-family:"Times New Roman"'>G</span><span lang=ZH-CN style='font-size:10.5pt'>，</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>B</span><span
lang=ZH-CN style='font-size:10.5pt'>三个分量表示用的字节数一样，不但没有任何便宜，还要加上一个</span><span
style='font-size:10.5pt;font-family:"Times New Roman"'>256×256×256×3</span><span
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