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//                        Intel License Agreement
//                For Open Source Computer Vision Library
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//M*/
#include "_cv.h"
 
#define _CV_SNAKE_BIG 2.e+38f
#define _CV_SNAKE_IMAGE 1
#define _CV_SNAKE_GRAD  2
 
 
/*F///////////////////////////////////////////////////////////////////////////////////////
//    Name:      icvSnake8uC1R    
//    Purpose:  
//    Context:  
//    Parameters:
//               src - source image,
//               srcStep - its step in bytes,
//               roi - size of ROI,
//               pt - pointer to snake points array
//               n - size of points array,
//               alpha - pointer to coefficient of continuity energy,
//               beta - pointer to coefficient of curvature energy, 
//               gamma - pointer to coefficient of image energy, 
//               coeffUsage - if CV_VALUE - alpha, beta, gamma point to single value
//                            if CV_MATAY - point to arrays
//               criteria - termination criteria.
//               scheme - image energy scheme
//                         if _CV_SNAKE_IMAGE - image intensity is energy
//                         if _CV_SNAKE_GRAD  - magnitude of gradient is energy
//    Returns:  
//F*/
 
static CvStatus
icvSnake8uC1R( unsigned char *src,   //原始图像数据
               int srcStep,         //每行的字节数
               CvSize roi,         //图像尺寸
               CvPoint * pt,       //轮廓点(变形对象)
               int n,            //轮廓点的个数
               float *alpha,       //指向α的指针，α能够是单个值，也能够是与轮廓点个数一致的数组
               float *beta,        //β的值，同α
               float *gamma,       //γ的值，同α
               int coeffUsage,   //确定αβγ是用作单个值还是个数组
        CvSize win,       //每一个点用于搜索的最小的领域大小,宽度为奇数
             CvTermCriteria criteria,   //递归迭代终止的条件准则
int scheme )         //确定图像能量场的数据选择，1为灰度，2为灰度梯度
{
    int i, j, k;
    int neighbors = win.height * win.width;    //当前点领域中点的个数
 
   //当前点的位置
    int centerx = win.width >> 1;          
    int centery = win.height >> 1;         
 
    float invn;        //n 的倒数？
    int iteration = 0;     //迭代次数
    int converged = 0;      //收敛标志，0为非收敛
    
  //能量
    float *Econt;    //
    float *Ecurv;   //轮廓曲线能量
    float *Eimg;    //图像能量
    float *E;      //
  
   //αβγ的副本
    float _alpha, _beta, _gamma;
 
    /*#ifdef GRAD_SNAKE */
    float *gradient = NULL;
    uchar *map = NULL;
    int map_width = ((roi.width - 1) >> 3) + 1;
    int map_height = ((roi.height - 1) >> 3) + 1;
    CvSepFilter pX, pY;
    #define WTILE_SIZE 8
    #define TILE_SIZE (WTILE_SIZE + 2)       
    short dx[TILE_SIZE*TILE_SIZE], dy[TILE_SIZE*TILE_SIZE];
    CvMat _dx = cvMat( TILE_SIZE, TILE_SIZE, CV_16SC1, dx );
    CvMat _dy = cvMat( TILE_SIZE, TILE_SIZE, CV_16SC1, dy );
    CvMat _src = http://www.mamicode.com/cvMat( roi.height, roi.width, CV_8UC1, src );>



转：http://shi-xj.blog.163.com/blog/static/3178051520110911234254/