canny.h

A tutorial and open source code for finding edges and corners based on the filters used in primary v

//////////////////////////////////////////////////////////////////
// Canny.h
// Original Code from:
//		Algorithms for Image Processing and Computer Vision
//		By J.R. Parker
// Modified for VisSDK by: Travis A Udd 11/30/00
//////////////////////////////////////////////////////////////////

#ifndef CANNY_H
#define CANNY_H

/* The image header data structure      */
struct header {
	int nr, nc;             /* Rows and columns in the image */
	int oi, oj;             /* Origin */
};

/*      The IMAGE data structure        */
struct image {
		struct header *info;            /* Pointer to header */
		unsigned char **data;           /* Pixel values */
};

#define SQRT2 1.414213562
#define BLACK 0
#define WHITE 1

typedef struct image * IMAGE;


struct imagec {
		struct header *info;            /* Pointer to header */
		unsigned char **data;           /* Pixel values */
};

//void CannyFilter(imagec *im);
void CannyFilter(imagec *im,int low,int high,double gaussian);
struct imagec  *newimagec (int nr, int nc);
void freeimagec (struct imagec  *z);

class Canny
{
public:
    Canny( CDefaultImage *imageSrc);
//    ~Canny();
	//////////////////////////////////////////////////////////////////
	// CannyEdgeDetect()
	// Travis A Udd 11/30/00
	// Function: Fills 2D buffer with image 
	// and runs canny filter function on it.
	// result is edges of found in image.
	//////////////////////////////////////////////////////////////////
	void CannyEdgeDetect(CVisRGBAByteImage *featureImage);
	void SetHighTreshold(int th){HighTh=th;}
	void SetLowerTreshold(int th){LowTh=th;}
	void SetGaussianDeviation(double gau){Gaussian=gau;}

private:
	/* Fraction of pixels that should be above the HIGH threshold */
	float ratio; // = 0.1f;
	int WIDTH; // = 0;

	int trace (int i, int j, int low, imagec* im,imagec* mag, imagec* ori);
	float gauss(float x, float sigma);
	float dGauss (float x, float sigma);
	float meanGauss (float x, float sigma);
	void hysteresis (int high, int low, imagec* im, imagec* mag, imagec* oriim);
	void canny (float s, imagec* im, imagec* mag, imagec* ori);
	void seperable_convolution (imagec* im, float *gau, int width, 
			float **smx, float **smy);
	void dxy_seperable_convolution (float** im, int nr, int nc, float *gau,  
			int width, float **sm, int which);
	void nonmax_suppress (float **dx, float **dy, int nr, int nc, 
			imagec* mag, imagec* ori);
	void estimate_thresh (imagec* mag, int *low, int *hi);
	float ** f2d (int nr, int nc);
	struct imagec  * newimagec (int nr, int nc);
	void freeimagec (struct imagec  *z);
	void CannyFilter(imagec *im,int low,int high,double gaussian);
	float norm (float x, float y);
	int range (imagec* im, int i, int j);


//  CVisImage<CVisRGBAUCharPixel> m_workingImage;
	CDefaultImage *m_pImage;
	int HighTh;
	int LowTh;
	double Gaussian;
};
#endif