canny 算法

void CreatGauss(double sigma, double **pdKernel, int *pnWidowSize)

void GaussianSmooth(SIZE sz, LPBYTE pGray, LPBYTE pResult, double sigma)

void Grad(SIZE sz, LPBYTE pGray, int *pGradX, int *pGradY, int *pMag)

void NonmaxSuppress(int *pMag, int *pGradX, int *pGradY, SIZE sz, LPBYTE pNSRst)

void EstimateThreshold(int *pMag, SIZE sz, int *pThrHigh, int *pThrLow, LPBYTE pGray,

double dRatHigh, double dRatLow)

void Hysteresis(int *pMag, SIZE sz, double dRatLow, double dRatHigh, LPBYTE pResult)

void TraceEdge(int y, int x, int nThrLow, LPBYTE pResult, int *pMag, SIZE sz)

void Canny(LPBYTE pGray, SIZE sz, double sigma, double dRatLow,

double dRatHigh, LPBYTE pResult)