chap03.htm

数字图像处理入门. 一位图像处理高手写的书. 从图像处理的最基础开始,然后慢慢以一些例子做说明,进入图像处理的更高阶段.学习图像处理不可多得的比较朴实的书

name="_Toc486332876"></a><a name="_Toc486338985"></a><a name="_Toc454810850"></a><a
name="_Toc454856624"><span><span>锐化</span></span></a></h2>
  <p style='line-height:18.0pt'><span
style='font-family:宋体;"Times New Roman"'>锐化</span><span lang=EN-US>(sharpening)</span><span
style='font-family:宋体;"Times New Roman"'>和平滑恰恰相反，它是通过增强高频分量来减少图象中的模糊，因此又称为高通滤波</span><span
lang=EN-US>(high pass filter)</span><span style='font-family:宋体;"Times New Roman";"Times New Roman"'>。锐化处理在增强图象边缘的同时增加了图象的噪声。</span></p>
  <p style='line-height:18.0pt'><span
style='font-family:宋体;"Times New Roman"'>常用的锐化模板是拉普拉斯</span><span lang=EN-US>(Laplacian)</span><span
style='font-family:宋体;"Times New Roman"'>模板</span><span lang=EN-US>(</span><span style='font-family:
宋体;&quot;Times New Roman&quot;'>见</span><span
lang=EN-US>(3.4)</span><span style='font-family:宋体;
&quot;Times New Roman&quot;'>式</span><span lang=EN-US>)</span><span
style='font-family:宋体;"Times New Roman"'>，又是个数学家的名字，可见学好数学，走遍天下都不怕。</span></p>
  <p align=center style='text-align:center;line-height:18.0pt'><span
lang=EN-US><sub> <img width=100 height=75
src="chap03.files/image067.gif"  v:shapes="_x0000_i1081"> </sub> </span></p>
  <p align=right style='text-align:right;line-height:18.0pt'><span
lang=EN-US>(3.4)</span></p>
  <p style='line-height:18.0pt'><span
style='font-family:宋体;"Times New Roman"'>容易看出拉普拉斯模板的作法：先将自身与周围的</span><span lang=EN-US>8</span><span
style='font-family:宋体;"Times New Roman"'>个象素相减，表示自身与周围象素的差别；再将这个差别加上自身作为新象素的灰度。可见，如果一片暗区出现了一个亮点，那么锐化处理的结果是这个亮点变得更亮，增加了图象的噪声。</span></p>
  <p style='line-height:18.0pt'><span
style='font-family:宋体;"Times New Roman"'>因为图象中的边缘就是那些灰度发生跳变的区域，所以锐化模板在边缘检测中很有用，这一点将在后面详细介绍。</span></p>
  <p style='line-height:18.0pt'><span
style='font-family:宋体;"Times New Roman"'>图</span><span lang=EN-US>3.1</span><span style='font-family:
宋体;&quot;Times New Roman&quot;'>经过拉普拉斯模板处理后，如图</span><span
lang=EN-US>3.4</span><span style='font-family:宋体;
&quot;Times New Roman&quot;'>所示</span></p>
  <p align=center style='text-align:center;line-height:18.0pt'><span
lang=EN-US> <img width=174 height=193
src="chap03.files/image068.gif"  v:shapes="_x0000_i1082"> </span></p>
  <p align=center style='text-align:center;line-height:18.0pt'><b><span
style='font-family:宋体;"Times New Roman"'>图</span>3.4&nbsp;&nbsp;&nbsp;&nbsp; </b><b><span
style='font-family:宋体;"Times New Roman"'>锐化</span><span lang=EN-US></span></b></p>
  <p style='line-height:18.0pt'><span
style='font-family:宋体;"Times New Roman"'>下面给出的程序是一个通用的</span><span lang=EN-US>3</span><span
style='font-family:宋体;"Times New Roman"'>×</span><span lang=EN-US>3</span><span style='font-family:
宋体;&quot;Times New Roman&quot;'>模板的函数，其中第二参数为模板类型，为如下定义的常量：</span></p>
  <p style='line-height:18.0pt'><span lang=EN-US>#define TEMPLATE_SMOOTH_BOX 1 
    //Box</span><span style='font-family:宋体;"Times New Roman";"Times New Roman"'>平滑模板</span></p>
  <p style='line-height:18.0pt'>#define TEMPLATE_SMOOTH_GAUSS&nbsp; 2 //<span
style='font-family:宋体;"Times New Roman"'>高斯平滑模板</span></p>
  <p style='line-height:18.0pt'><span lang=EN-US>#define TEMPLATE_SHARPEN_LAPLACIAN 
    3 //</span><span style='font-family:宋体;"Times New Roman";"Times New Roman"'>拉普拉斯锐化模板</span></p>
  <p style='line-height:18.0pt'><span
style='font-family:宋体;"Times New Roman"'>对应的模板数组如下</span></p>
  <p style='line-height:18.0pt'><span lang=EN-US>int Template_Smooth_Box[9]={1,1,1,1,1,1,1,1,1};</span></p>
  <p style='line-height:18.0pt'><span lang=EN-US>int Template_Smooth_Gauss[9]={1,2,1,2,4,2,1,2,1};</span></p>
  <p style='line-height:18.0pt'><span lang=EN-US>int Template_Sharpen_Laplacian[9]={-1,-1,-1,-1,9,-1,-1,-1,-1};</span><span
lang=EN-US style='font-size:9.0pt;'></span></p>
  <p style='line-height:18.0pt'><span
style='font-family:宋体;"Times New Roman"'>以后我们碰到其它的模板，仍然要用这个函数，所做的操作只是增加一个常量标识，及其对应的模板数组。</span></p>
  <p style='line-height:18.0pt'><span
style='font-family:宋体;"Times New Roman"'>要注意的是，运算后如果出现了大于</span><span lang=EN-US>255</span><span
style='font-family:宋体;"Times New Roman"'>或者小于</span><span lang=EN-US>0</span><span style='font-family:
宋体;&quot;Times New Roman&quot;'>的点，称为溢出，溢出点的处理通常是截断，即大于</span><span
lang=EN-US>255</span><span style='font-family:宋体;
&quot;Times New Roman&quot;'>时，令其等于</span><span lang=EN-US>255</span><span
style='font-family:宋体;"Times New Roman"'>；小于</span><span lang=EN-US>0</span><span style='font-family:
宋体;&quot;Times New Roman&quot;'>时，取其绝对值。</span></p>
  <p style='line-height:18.0pt'><span
style='font-family:宋体;"Times New Roman"'>这段程序和前几章介绍的代码许多地方是很相似的，所以注释简单一些。程序中并没有用到那种分解成两个一维模板的快速算法，你如果有兴趣，可以自己编着试试。</span></p>
  <p style='line-height:18.0pt'><span lang=EN-US>BOOL TemplateOperation(HWND hWnd, 
    int TemplateType)</span></p>
  <p style='line-height:18.0pt'><span lang=EN-US>{</span></p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>DWORD&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; OffBits,BufSize;</p>
  <p style='line-height:18.0pt'>LPBITMAPINFOHEADER&nbsp;&nbsp;&nbsp; lpImgData;</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>LPSTR&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    &nbsp;&nbsp;&nbsp;&nbsp; lpPtr;</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>HLOCAL&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    &nbsp;&nbsp; hTempImgData;</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>LPBITMAPINFOHEADER&nbsp;&nbsp;&nbsp; 
    lpTempImgData;</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>LPSTR&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    &nbsp; lpTempPtr;</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>HDC&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    &nbsp;&nbsp;&nbsp; hDc;</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>HFILE&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    hf;</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>LONG&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    x,y;</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>float&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    coef;&nbsp; //<span style='font-family:宋体;"Times New Roman";"Times New Roman"'>模板前面所乘的系数</span></p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>int&nbsp; 
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    &nbsp;&nbsp;&nbsp;&nbsp; CoefArray[9]; //<span style='font-family:宋体;
&quot;Times New Roman&quot;'>模板数组</span></p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>float&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; TempNum;</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>char&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; filename[80];</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>switch(TemplateType){ 
    //<span style='font-family:宋体;
&quot;Times New Roman&quot;'>判断模板类型</span></p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>case 
    TEMPLATE_SMOOTH_BOX: //Box<span style='font-family:宋体;"Times New Roman";"Times New Roman"'>平滑模板</span></p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </span>coef=(float)(1.0/9.0);</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </span>memcpy(CoefArray,Template_Smooth_Box,9*sizeof(int));</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </span>strcpy(filename,&quot;c:\\smbox.bmp&quot;); </p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </span>break;</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>case 
    TEMPLATE_SMOOTH_GAUSS: //<span style='font-family:宋体;"Times New Roman";"Times New Roman"'>高斯平滑模板</span></p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </span>coef=(float)(1.0/16.0);</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </span>memcpy(CoefArray,Template_Smooth_Gauss,9*sizeof(int));</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </span>strcpy(filename,&quot;c:\\smgauss.bmp&quot;);</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </span>break;</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>case 
    TEMPLATE_SHARPEN_LAPLACIAN:&nbsp; //<span
style='font-family:宋体;"Times New Roman"'>拉普拉斯锐化模板</span></p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </span>coef=(float)1.0;</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </span>memcpy(CoefArray,Template_Sharpen_Laplacian,9*sizeof(int));</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </span>strcpy(filename,&quot;c:\\shlaplac.bmp&quot;);</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </span>break;</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>}</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>OffBits=bf.bfOffBits-sizeof(BITMAPFILEHEADER);</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>BufSize=OffBits+bi.biHeight*LineBytes;</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>if((hTempImgData=LocalAlloc(LHND,BufSize))==NULL)</p>
  <p style='line-height:18.0pt'><span
lang=EN-US>{</span></p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp; </span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    MessageBox(hWnd,&quot;Error alloc memory!&quot;,&quot;Error Message&quot;,MB_OK|</p>
  <p style='line-height:
18.0pt'><span lang=EN-US>MB_ICONEXCLAMATION);</span></p>
  <p style='line-height:
18.0pt'><span lang=EN-US>return FALSE;</span></p>
  <p style='line-height:18.0pt'><span
lang=EN-US>}</span></p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp; </span>&nbsp; lpImgData=(LPBITMAPINFOHEADER)GlobalLock(hImgData);&nbsp;&nbsp;&nbsp; 
  </p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>lpTempImgData=(LPBITMAPINFOHEADER)LocalLock(hTempImgData);</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>lpPtr=(char 
    *)lpImgData;</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>lpTempPtr=(char 
    *)lpTempImgData;</p>
  <p style='line-height:18.0pt'><span
lang=EN-US>//</span><span style='font-family:宋体;
&quot;Times New Roman&quot;'>先将原图直接拷贝过来，其实主要是拷贝周围一圈的象素</span></p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>memcpy(lpTempPtr,lpPtr,BufSize); 
  </p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>for(y=1;y&lt;bi.biHeight-1;y++) 
    //<b><span style='font-family:黑体'>注意<span lang=EN-US>y的范围是从1到bi.biHeight-2</span></span></b></p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </span>for(x=1;x&lt;bi.biWidth-1;x++){ //<b><span style='font-family:黑体'>注意<span lang=EN-US>x的范围是从1到bi.biWidth-2</span></span></b></p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </span>lpPtr=(char *)lpImgData+(BufSize-LineBytes-y*LineBytes)+x;</p>
  <p style='line-height:18.0pt'><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </span>lpTempPtr=(cha