[转载] DSP6000图像位移与变形典型算法

原文地址：转载：DSP6000图像位移与变形典型算法作者：Jane

李现路:DSP6000图像位移与变形典型算法
一、图像的平移算法
图像平移的数学表达式原理：
初始坐标为（x0，y0）的点经过平移（tx，ty）（以向右，向下为正方向）后，坐标变为（x1，y1）。这两点之间的关系是x1=x0+tx，y1=y0+ty。
这样，平移后的图像上的每一点都可以在原图像中找到对应的点。例如，对于新图中的（0，0）像素，代入上面的议程组，可以求出对应原图中的点，可以直接将它的像素值同意设置为0或者255（对于灰度图就是黑色或白色）。
同样，若有点不在原图中，也就说明原图中有点被移出显示区域。如果不想丢失被移出的部分图像，可以将新生成的图像扩大tx，高度扩大ty。
平移处理的C语言代码：

Int intXOffset=-200; //水平偏移量
Int intYOffset=-200; //垂直偏移量，必须是2的整数
void geometryTrans()
{
    inti,j;
    intintCapX,intCapY;
   for(i=0;i<numLines;i++) //行数
    {
       for(j=0;j<numPixels;j++) //像素数 /每行
       {                
           intCapX = j-intXOffset;
           intCapY =i-intYOffset/2;            
           // 判断 是否在原图范围内
           if((intCapX>=0) &&(intCapX<numPixels))  
           {  
               //奇数行
               if((i<numLines/2) &&(intCapY>=0) &&(intCapY<numLines/2))
               {
                   // 传送亮度信号
                   *(Uint8 *)(tempYbuffer + i*numPixels + j) = *(Uint8 *)(capYbuffer +(i-intYOffset/2)*numPixels +intCapX);  
               }
               //偶数行
               else if((i>=numLines/2)&& (i<numLines)&&(intCapY>=numLines/2)&&(intCapY<numLines))
               {
                    // 传送亮度信号
                   *(Uint8 *)(tempYbuffer + i*numPixels + j) = *(Uint8 *)(capYbuffer +(i-intYOffset/2)*numPixels +intCapX);                
               }
               else
               {
                   *(Uint8 *)(tempYbuffer + i*numPixels + j) = 0xFF;
               }                                                                            
           }
           else
           {
                *(Uint8 *)(tempYbuffer + i*numPixels + j) = 0xFF;
           }                                  
       }    
    }
}    
二、图像的垂直镜像变换算法
数学表达式原理：
设图像高度为IHeight，宽度为IWidth，原图中（x0，y0）垂直镜像后将变为（x0，
IHeight-y0），其表达式为：
设图像高度为IHeight，宽度为IWidth，原图中（x0，y0）垂直镜像后将变为（x0，
IHeight-y0），其表达式为：
X0=x1; y0=IHeight-y1
算法的C语言代码：
    portNumber =0;
    vpHchannel0= bt656_8bit_ncfc(portNumber);
   bt656_capture_start(vpHchannel0);
   
   while(capNewFrame == 0){}
   
    capNewFrame=0;
   for(i=0;i<numLines;i++)
    {
          
          //前半部分为原始图像
       DAT_copy((void *)(capYbuffer + i * numPixels),
                (void *)(disYbuffer + i * numPixels),
                numPixels>>1);
       //后半部分为垂直镜像图像
       DAT_copy((void *)(capYbuffer + i * numPixels),
        (void *)(disYbuffer + (numPixels>>1)+ (numLines-1-i) * numPixels),
        numPixels>>1);
       
       //前半部分为原始图像
       DAT_copy((void *)(capCbbuffer + i * (numPixels>> 1)),
                (void *)(disCbbuffer + i * (numPixels>> 1)),
                numPixels>>2);
       //后半部分为垂直镜像图像
       DAT_copy((void *)(capCbbuffer + i * (numPixels>> 1)),
                (void *)(disCbbuffer + (numPixels>>2)+ (numLines-1-i) * (numPixels >>1)),
                numPixels>>2);                        
       
       //前半部分为原始图像
       DAT_copy((void *)(capCrbuffer + i * (numPixels>> 1)),
                (void *)(disCrbuffer + i * (numPixels>> 1)),
                numPixels>>2);
       //后半部分为垂直镜像图像        
       DAT_copy((void *)(capCrbuffer + i * (numPixels>> 1)),
                (void *)(disCrbuffer + (numPixels>>2)+ (numLines-1-i) * (numPixels >>1)),
                numPixels>>2);            
    }    
   
   bt656_display_start(vpHchannel1);
   
   for(;;)
    {
       
       if((capNewFrame == 1)&&(disNewFrame== 1))
       {
           
           capNewFrame =0;
           disNewFrame =0;
           for(i=0;i<numLines;i++)
           {
                  
                  //前半部分为原始图像
               DAT_copy((void *)(capYbuffer + i * numPixels),
                        (void *)(disYbuffer + i * numPixels),
                        numPixels>>1);
               //后半部分为垂直镜像图像
               DAT_copy((void *)(capYbuffer + i * numPixels),
                (void *)(disYbuffer + (numPixels>>1)+ (numLines-1-i) * numPixels),
                numPixels>>1);
               
               //前半部分为原始图像
               DAT_copy((void *)(capCbbuffer + i * (numPixels>> 1)),
                        (void *)(disCbbuffer + i * (numPixels>> 1)),
                        numPixels>>2);
               //后半部分为垂直镜像图像
               DAT_copy((void *)(capCbbuffer + i * (numPixels>> 1)),
                        (void *)(disCbbuffer + (numPixels>>2)+ (numLines-1-i) * (numPixels >>1)),
                        numPixels>>2);                        
               
               //前半部分为原始图像
               DAT_copy((void *)(capCrbuffer + i * (numPixels>> 1)),
                        (void *)(disCrbuffer + i * (numPixels>> 1)),
                        numPixels>>2);
               //后半部分为垂直镜像图像        
               DAT_copy((void *)(capCrbuffer + i * (numPixels>> 1)),
                        (void *)(disCrbuffer + (numPixels>>2)+ (numLines-1-i) * (numPixels >>1)),
                        numPixels>>2);            
            }
       }
   }    
}
三、图像的水平镜像变换算法
数学表达式原理：
设图像高度为IHeight，宽度为IWidth，原图中（x0,y0）经过水平镜像后从未将变为
（IWidth-x0，y0），其表达式为：
X0=IWidth-y1; y0=y1
算法的C语言代码：

void horizTranspose()
{
    inti,j;
   for(i=0;i<numLines;i++)
   {          
          
          //传送临时Y缓冲区
       DAT_copy((void *)(capYbuffer + i * numPixels),
                (void *)(tempYbuffer + i * numPixels),
                numPixels>>1);                                    
       //传送临时Cb缓冲区
       DAT_copy((void *)(capCbbuffer + i * (numPixels>> 1)),
                (void *)(tempCbbuffer + i * (numPixels>> 1)),
                numPixels>>2);        
       //传送临时Cr缓冲区
       DAT_copy((void *)(capCrbuffer + i * (numPixels>> 1)),
                (void *)(tempCrbuffer + i * (numPixels>> 1)),
                numPixels>>2);                                                          
       
       for(j=numPixels/2;j<numPixels;j++)
       {
           //传送临时Y缓冲区        
           *(Uint8 *)(tempYbuffer + i*numPixels + j) = *(Uint8 *)(capYbuffer +i*numPixels +numPixels-1-j);        
       }
       for(j=(numPixels>>2);j<(numPixels>>1);j++)
       {
           //传送临时Cb缓冲区
           *(Uint8 *)(tempCbbuffer +i*(numPixels>>1) + j) = *(Uint8*)(capCbbuffer + i*(numPixels>>1) +(numPixels>>1)-1-j);        
           //传送临时Cr缓冲区
           *(Uint8 *)(tempCrbuffer +i*(numPixels>>1) + j) = *(Uint8*)(capCrbuffer + i*(numPixels>>1) +(numPixels>>1)-1-j);        
       }
    }
}
四、图像的缩放算法
数学表达式原理：
假设图像x轴方向缩放比率fx，y轴方向缩放比率是fy，那么原图中点（x0，y0）对应
于新图中的点（x1，y1）的转换表达式为：
X0=x1/fx; y0=y1/fy
算法的C语言代码：

Float fXZoomRatio=0.5; //水平缩放比率
Float fYZoomRatio=0.5; //垂直缩放比率

void zoom()
{
    inti,j;
    intintCapX,intCapY;
   for(i=0;i<numLines;i++)
    {
       for(j=0;j<numPixels;j++)
       {                
           intCapX = (int)(j/fYZoomRatio+0.5);
           intCapY =(int)(i/fXZoomRatio+0.5);          
           //判断是否在原图范围内
           if((intCapX>=0) &&(intCapX<numPixels))  
           {  
               if((i<numLines/2) &&(intCapY>=0) &&(intCapY<numLines/2))
               {
                   //传送亮度信号
                   *(Uint8 *)(tempYbuffer + i*numPixels + j) = *(Uint8 *)(capYbuffer +intCapY*numPixels +intCapX);  
               }
               else if((i>=numLines/2)&& (i<numLines)&&(intCapY>=numLines/2)&&(intCapY<numLines))
               {
                    //传送亮度信号
                   *(Uint8 *)(tempYbuffer + i*numPixels + j) = *(Uint8 *)(capYbuffer +intCapY*numPixels +intCapX);                
               }
               else
               {
                   *(Uint8 *)(tempYbuffer + i*numPixels + j) = 0xFF;
               }                                                                            
           }
           else
           {
                *(Uint8 *)(tempYbuffer + i*numPixels + j) = 0xFF;
           }                                  
       }    
    }
}
五、图像的旋转实验
数学表达式原理：
下面我们来推导一下旋转运算的变换公式。如下图所示，点（x0，y0）经过旋转θ度后
坐标变成（x1，y1）。其数学表达式为：
X0=x1cos(θ)+y1sin(θ)+ccos(θ)-dsin(θ)+a ;
Y0=-xsin(θ)+y1cos(θ)+csin(θ)-dcos(θ)+ b
算法的C语言代码：

Float fAngle=3.1415927/3; //旋转的角度
*画矩形边框函数*/
Void drawRectangle();
*计算图像旋转参数*/
Void computeParameter();

void rotate()
{
    inti,j,intInc;
    intintCapYInc;
    intintCapX,intCapY;
   
   //方框内奇数行
   for(i=intALines;i<intDLines;i++)
    {
       for(j=intAPixels;j<intDPixels;j++)
       {
           intInc = i*2;  
           intCapX    =(int)(j*cosAngle + intInc*sinAngle + f1 + 0.5);
           intCapYInc = (int)(intInc*cosAngle - j*sinAngle + f1 +0.5);          
           if((intCapYInc%2)==0)
           {
               intCapY = intCapYInc/2;
           }
           else
           {
               intCapY = (intCapYInc-1)/2+numLines/2;
           }
           //判断是否在原图范围内
           if((intCapX>=0) &&(intCapX<numPixels)&& (intCapY>=0)&&(intCapY<numLines))  
           {
               //传送亮度信号
               *(Uint8 *)(tempYbuffer + i*numPixels + j) = *(Uint8 *)(capYbuffer +intCapY*numPixels +intCapX);                                                                        
           }
           else
           {
                *(Uint8 *)(tempYbuffer + i*numPixels + j) = 0xFF;
           }
       }    
    }
   //方框内偶数行
   for(i=numLines/2+intALines;i<numLines/2+intDLines;i++)
    {
       for(j=intAPixels;j<intDPixels;j++)
       {        
           intInc = (i-numLines/2)*2 + 1;
           intCapX    =(int)(j*cosAngle + intInc*sinAngle + f1 + 0.5);
           intCapYInc = (int)(intInc*cosAngle - j*sinAngle + f1 +0.5);          
           if((intCapYInc%2)==0)
           {
               intCapY = intCapYInc/2;
           }
           else
           {
               intCapY = (intCapYInc-1)/2+numLines/2;
           }            
           //判断是否在原图范围内
           if((intCapX>=0) &&(intCapX<numPixels)&& (intCapY>=0)&&(intCapY<numLines))  
           {
               //传送亮度信号
               *(Uint8 *)(tempYbuffer + i*numPixels + j) = *(Uint8 *)(capYbuffer +intCapY*numPixels +intCapX);                                                                        
           }
           else
           {
                *(Uint8 *)(tempYbuffer + i*numPixels + j) = 0xFF;
           }
       }    
   }    
}
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                                             曙海教育
                                           曙海嵌入式学院
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