Sobel算子的C代码

/* Sobel templatea00 a01 a02a10 a11 a12a20 a21 a22*/unsigned char a00, a01, a02unsigned char a10, a11, a12unsigned char a20, a21, a22void MySobel(IplImage* gray, IplImage* gradient){CvScalar color for (int i=1 i<gray->height-1 ++i){for (int j=1 j<gray->width-1 ++j){a00 = cvGet2D(gray, i-1, j-1).val[0]a01 = cvGet2D(gray, i-1, j).val[0]a02 = cvGet2D(gray, i-1, j+1).val[0]a10 = cvGet2D(gray, 或孙毁i, j-1).val[0]a11 = cvGet2D(gray, i, j).val[0]a12 = cvGet2D(gray, i, j+1).val[0]a20 = cvGet2D(gray, i+1, j-1).val[0]a21 = cvGet2D(gray, 衫备i+1, j).val[0]a22 = cvGet2D(gray, i+1, j+1).val[0]// x方向上的近似导数double ux = a20 * (1) + a21 * (2) + a22 * (1)+ (a00 * (-1) + a01 * (-2) + a02 * (-1))// y方向上的近似导数double uy = a02 * (1) + a12 * (2) + a22 * (1)+ a00 * (-1) + a10 * (-2) + a20 * (-1)color.val[0] = sqrt(ux*ux + uy*uy)cvSet2D(gradient, i, j, color)}}}//注释:该程序需要在安装Opencv软件下运行。Matlabps=imread('D:\14.jpg') %读取图像subplot(1,3,1)imshow(ps)title('原图像')ps=rgb2gray(ps)[m,n]=size(ps) %用Sobel微分算子进行边缘检测pa = edge(ps,'sobel')subplot(1,3,2)imshow(pa)title('Sobel边缘检测得到凯返的图像')

FILE: edgeSob.c - WORKS!!

AUTH: Bill Green

DESC: 2 3x3 Sobel masks for edge detection

DATE: 07/23/02

REFS: edgeLap.c

*/

#include <stdio.h>

#include <stdlib.h>

#include <math.h>

#include <alloc.h>

/*-------STRUCTURES---------*/

typedef struct {int rowsint colsunsigned char* data} sImage

/*-------PROTOTYPES---------*/

long getImageInfo(FILE*, long, int)

void copyImageInfo(FILE* inputFile, FILE* outputFile)

void copyColorTable(FILE* inputFile, FILE* outputFile, int nColors)

int main(int argc, char* argv[])

{

FILE *bmpInput, *bmpOutput

sImage originalImage

sImage edgeImage

unsigned int X, Y

int I, J

long sumX, sumY

int nColors, SUM

unsigned long vectorSize

unsigned long fileSize

int GX[3][3]

int GY[3][3]

unsigned char *pChar, someChar

unsigned int row, col

someChar = '0'pChar = &someChar

/* 3x3 GX Sobel mask. Ref: www.cee.hw.ac.uk/hipr/html/sobel.html */

GX[0][0] = -1GX[0][1] = 0GX[0][2] = 1

GX[1][0] = -2GX[1][1] = 0GX[1][2] = 2

GX[2][0] = -1GX[2][1] = 0GX[2][2] = 1

/* 3x3 GY Sobel mask. Ref: www.cee.hw.ac.uk/hipr/html/sobel.html */

GY[0][0] = 1GY[0][1] = 2GY[0][2] = 1

GY[1][0] = 0GY[1][1] = 0GY[1][2] = 0

GY[2][0] = -1GY[2][1] = -2GY[2][2] = -1

if(argc <2) {

printf("Usage: %s bmpInput.bmp\n", argv[0])

exit(0)

}

printf("Reading filename %s\n", argv[1])

/*-------DECLARE INPUT &OUTPUT FILES-------*/

bmpInput = fopen(argv[1], "rb")

bmpOutput = fopen("edgeSob.bmp", "wb")

/*---SET POINTER TO BEGINNING OF FILE----*/

fseek(bmpInput, 0L, SEEK_END)

/*-------GET INPUT BMP DATA--------*/

fileSize = getImageInfo(bmpInput, 2, 4)

originalImage.cols = (int)getImageInfo(bmpInput, 18, 4)

originalImage.rows = (int)getImageInfo(bmpInput, 22, 4)

edgeImage.rows = originalImage.rows

edgeImage.cols = originalImage.cols

/*--------PRINT DATA TO SCREEN----------*/

printf("Width: %d\n", originalImage.cols)

printf("Height: %d\n", originalImage.rows)

printf("File size: %lu\n", fileSize)

nColors = (int)getImageInfo(bmpInput, 46, 4)

printf("nColors: %d\n", nColors)

/*------ALLOCATE MEMORY FOR FILES--------*/

vectorSize = fileSize - (14+40+4*nColors)

printf("vectorSize: %lu\n", vectorSize)

edgeImage.data = farmalloc(vectorSize*sizeof(unsigned char))

if(edgeImage.data == NULL) {

printf("Failed to malloc edgeImage.data\n")

exit(0)

}

printf("%lu bytes malloc'ed for edgeImage.data\n", vectorSize)

originalImage.data = farmalloc(vectorSize*sizeof(unsigned char))

if(originalImage.data == NULL) {

printf("Failed to malloc originalImage.data\n")

exit(0)

}

printf("%lu bytes malloc'ed for originalImage.datt\n", vectorSize)

/*------COPY HEADER AND COLOR TABLE---------*/

copyImageInfo(bmpInput, bmpOutput)

copyColorTable(bmpInput, bmpOutput, nColors)

fseek(bmpInput, (14+40+4*nColors), SEEK_SET)

fseek(bmpOutput, (14+40+4*nColors), SEEK_SET)

/* Read input.bmp and store it's raster data into originalImage.data */

for(row=0row<=originalImage.rows-1row++) {

for(col=0col<=originalImage.cols-1col++) {

fread(pChar, sizeof(char), 1, bmpInput)

*(originalImage.data + row*originalImage.cols + col) = *pChar

}

}

/*---------------------------------------------------

SOBEL ALGORITHM STARTS HERE

---------------------------------------------------*/

for(Y=0Y<=(originalImage.rows-1)Y++) {

for(X=0X<=(originalImage.cols-1)X++) {

sumX = 0

sumY = 0

/* image boundaries */

if(Y==0 || Y==originalImage.rows-1)

SUM = 0

else if(X==0 || X==originalImage.cols-1)

SUM = 0

/* Convolution starts here */

else {

/*-------X GRADIENT APPROXIMATION------*/

for(I=-1I<=1I++) {

for(J=-1J<=1J++) {

sumX = sumX + (int)( (*(originalImage.data + X + I + (Y + J)*originalImage.cols)) * GX[I+1][J+1])

}

}

if(sumX>255) sumX=255

if(sumX<0)sumX=0

/*-------Y GRADIENT APPROXIMATION-------*/

for(I=-1I<=1I++) {

for(J=-1J<=1J++) {

sumY = sumY + (int)( (*(originalImage.data + X + I + (Y + J)*originalImage.cols)) * GY[I+1][J+1])

}

}

if(sumY>255) sumY=255

if(sumY<0) sumY=0

SUM = abs(sumX) + abs(sumY)/*---GRADIENT MAGNITUDE APPROXIMATION (Myler p.218)----*/

}

*(edgeImage.data + X + Y*originalImage.cols) = 255 - (unsigned char)(SUM) /* make edges black and background white */

fwrite( (edgeImage.data + X + Y*originalImage.cols), sizeof(char), 1, bmpOutput)

}

}

printf("See edgeSob.bmp for results\n")

fclose(bmpInput)

fclose(bmpOutput)

farfree(edgeImage.data) /* Finished with edgeImage.data */

farfree(originalImage.data) /* Finished with originalImage.data */

return 0

}

/*----------GET IMAGE INFO SUBPROGRAM--------------*/

long getImageInfo(FILE* inputFile, long offset, int numberOfChars)

{

unsigned char *ptrC

longvalue = 0L

unsigned char dummy

inti

dummy = '0'

ptrC = &dummy

fseek(inputFile, offset, SEEK_SET)

for(i=1i<=numberOfCharsi++)

{

fread(ptrC, sizeof(char), 1, inputFile)

/* calculate value based on adding bytes */

value = (long)(value + (*ptrC)*(pow(256, (i-1))))

}

return(value)

} /* end of getImageInfo */

/*-------------COPIES HEADER AND INFO HEADER----------------*/

void copyImageInfo(FILE* inputFile, FILE* outputFile)

{

unsigned char *ptrC

unsigned char dummy

inti

dummy = '0'

ptrC = &dummy

fseek(inputFile, 0L, SEEK_SET)

fseek(outputFile, 0L, SEEK_SET)

for(i=0i<=50i++)

{

fread(ptrC, sizeof(char), 1, inputFile)

fwrite(ptrC, sizeof(char), 1, outputFile)

}

}

/*----------------COPIES COLOR TABLE-----------------------------*/

void copyColorTable(FILE* inputFile, FILE* outputFile, int nColors)

{

unsigned char *ptrC

unsigned char dummy

inti

dummy = '0'

ptrC = &dummy

fseek(inputFile, 54L, SEEK_SET)

fseek(outputFile, 54L, SEEK_SET)

for(i=0i<=(4*nColors)i++) /* there are (4*nColors) bytesin color table */

{

fread(ptrC, sizeof(char), 1, inputFile)

fwrite(ptrC, sizeof(char), 1, outputFile)

}

}