图片处理（四）之边沿检测

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本代码主要工作是对图片的数据进行边沿检测。

检测边界这里会说两种方法，一种叫Laplacian边沿检测，另一种叫Sobel边沿检测，Laplacian计算量相对较少，Sobel边沿更清晰。

首先我们要有一个概念，当对图片的数据进行一次求导后，得到的是图片的色差变化速度，当对图片的数据进行二次求导后，得到的是图片色差变化速度的速度，即色差突变，当我们收集所有的色差突变数据，得到的就是图片的边沿。

Laplacian边沿检测：二次求导，直接对xy整合计算，得到：

@(@f )= f(x,y+1)+ f(x,y-1)+ f(x+1,y)+f(x-1,y)+ -4f(x,y) //@表示求导

即：

| 0 | 1 | 0 |

| 1 | -4 | 1 |

| 0 | 1 | 0 |

Sobel边沿检测：二次求导，x与y分开计算再整合，得到：//@表示求导

@(@fx)=[f(x+1,y-1)+2f(x+1,y)+f(x+1,y+1)]-[f(x-1,y-1)+2f(x-1,y)+f(x-1,y+1)]

| -1 | 0 | 1 |

| -2 | 0 | 2 |

| -1 | 0 | 1 |

@(@fx)=[f(x-1,y-1)+2f(x,y-1)+f(x+1,y-1)]-[f(x-1,y+1)+2f(x,y+1)+f(x+1,y+1)]

| 1 | 2 | 1 |

| 0 | 0 | 0 |

| -1 | -2 | -1 |

为整合计算，直接取绝对值进行相加，获取边沿数据，得到：

@(@f )= Abs( @(@fx) )+abs( @(@fx) )

//GraphEdgeHandle1 Sobel边沿检测

//GraphEdgeHandle Laplacian边沿检测

实现代码如下：

#include<stdio.h>

#include<stdlib.h>

#include<string.h>

#include<math.h>

#define ADD 0

#define SUB 1

#define MUL 2

#define DIV 3

#define Y_ADD 0

#define Y_SUB 1

#define CUR_POS(x,y,width) ((y)*width+(x))

#define X_POS(pos) ((pos)%PicWidth)

#define Y_POS(pos) ((pos)/PicWidth)

#define RANGE(x) (x<0?0:(x>255?255:x))

//---------------picattribute----------------------

unsignedint PicWidth;

unsignedint PicHeight;

//--------------------------------------------------

voidGraphBrightHandle(unsigned char *src, unsigned char *dest, int size, int type,double num);

voidGraphLPFHandle(unsigned char *src, unsigned char *dest, unsigned int Width,unsigned int Height);

voidGraphEdgeHandle (unsigned char *src, unsigned char *dest, unsigned int Width,unsigned int Height);

voidGraphEdgeHandle1(unsigned char *src, unsigned char *dest, unsigned int Width,unsigned int Height);

intmain(int argc,char** argv)

{

int nErrorCode=0;

FILE *fin;

FILE *fout_Bright;

FILE *fout_LPF;

FILE *fout_Edge;

char szInFilename[256];

char szOutFilename[256];

if(argc>=2)

{

strcpy(szInFilename ,argv[1]);

}

else

{

strcpy(szInFilename, "44.raw");

}

printf("src:%s\n",szInFilename);

if(argc>=4)

{

PicWidth = atoi(argv[2]);

PicHeight= atoi(argv[3]);

}

else

{

PicWidth = 640;

PicHeight= 480;

}

printf("PicWidth:%d,PicHeight:%d\n",PicWidth,PicHeight);

fin = fopen(szInFilename , "rb");

fout_Bright =fopen("GraphBright.raw" ,"wb");

fout_LPF = fopen("GraphLPF.raw" , "wb");

fout_Edge = fopen("GraphEdge.raw" , "wb");

if(fin && fout_Bright &&fout_LPF && fout_Edge)

{

//getthe input file size

unsignedint FileSize = 0;

fseek(fin,0, SEEK_END);

FileSize= ftell(fin);

fseek(fin,0, SEEK_SET);

printf("Filesize : %d\n", FileSize);

//geta memory

unsignedchar *DataBuf = (unsigned char *)malloc(FileSize);

memset(DataBuf,0, FileSize);

//readdata to DataBuf

if ( 0 == fread(DataBuf, FileSize, 1,fin) )

{

nErrorCode |= 0x4;

}

#if0 //Brignt Handle

GraphBrightHandle(DataBuf,DataBuf, FileSize, MUL, 1.5);

if( 0 == fwrite(DataBuf, FileSize, 1, fout_Bright) )

{

nErrorCode |= 0x8;

}

#endif

#if0 //LFP Handle

unsignedchar *DataBufLPF = (unsigned char *)malloc(FileSize);

memset(DataBufLPF,0, FileSize);

GraphLPFHandle(DataBuf,DataBufLPF, PicWidth, PicHeight);

if( 0 == fwrite(DataBufLPF, FileSize, 1, fout_LPF) )

{

nErrorCode |= 0x10;

}

#endif

#if1 //Edge check

unsignedchar *DataBufEdge = (unsigned char *)malloc(FileSize);

memset(DataBufEdge,0, FileSize);

GraphEdgeHandle1(DataBuf,DataBufEdge, PicWidth, PicHeight);

if( 0 == fwrite(DataBufEdge, FileSize, 1, fout_Edge) )

{

nErrorCode |= 0x11;

}

#endif

}

else

{

nErrorCode|= 0x01;

}

if(fin)

{

fclose(fin);

}

if(fout_Bright)

{

fclose(fout_Bright);

}

if(fout_LPF)

{

fclose(fout_LPF);

}

printf("nErrorCode: %d\n",nErrorCode);

system("pause");

return nErrorCode;

}

voidGraphBrightHandle(unsigned char *src, unsigned char *dest, int size, int type,double num)

{

int i = 0;

int R = 0, G = 0, B = 0;

for(i = 0; i < size; i+=3)

{

R= src[i+0];

G= src[i+1];

B= src[i+2];

switch(type)

{

case ADD: R += num; G += num; B += num; break;

case SUB: R -= num; G -= num; B -= num; break;

case MUL: R *= num; G *= num; B *= num; break;

case DIV: R /= num; G /= num; B /= num; break;

default: printf("no exist Brighttype\n"); break;

}

if(R< 0) R = 0;

if(G< 0) G = 0;

if(B< 0) B = 0;

if(R> 255) R = 255;

if(G> 255) G = 255;

if(B> 255) B = 255;

dest[i+0]= R;

dest[i+1]= G;

dest[i+2]= B;

}

voidGraphLPFHandle(unsigned char *src, unsigned char *dest, unsigned int Width,unsigned int Height)

{

unsigned int C, U, D, R, L;

int x, y;

double tmp;

for(y = 0; y < Height; y++)

{

for(x = 0; x < Width; x++)

{

C = CUR_POS(x,y,Width);

(0 == x)? (L = C):( L = y*Width + (x-1) );

(Width-1 == x)? (R = C):( R = y*Width + (x+1) );

(0 == y)? (U = C):( U = (y-1)*Width + x );

(Height-1 == y)? (D = C):( D =(y+1)*Width + x );

tmp =*(src+3*C+0)*0.5

+*(src+3*L+0)*0.125

+*(src+3*R+0)*0.125

+*(src+3*U+0)*0.125

+*(src+3*D+0)*0.125;

*(dest+3*C+0) = tmp;

tmp = *(src+3*C+1)*0.5

+*(src+3*L+1)*0.125

+*(src+3*R+1)*0.125

+*(src+3*U+1)*0.125

+*(src+3*D+1)*0.125;

*(dest+3*C+1) = tmp;

tmp = *(src+3*C+2)*0.5

+*(src+3*L+2)*0.125

+*(src+3*R+2)*0.125

+*(src+3*U+2)*0.125

+*(src+3*D+2)*0.125;

*(dest+3*C+2) = tmp;

}

voidGraphEdgeHandle1(unsigned char *src, unsigned char *dest, unsigned int Width,unsigned int Height)

{

int x, y;

int xA,xB,xC,xD,xE,xF;

int yA,yB,yC,yD,yE,yF;

int Sx,Sy,tmp;

for(y = 1; y < Height-1; y++)

{

for(x = 1; x < Width-1; x++)

{

xA = (y-1)*Width + (x-1);

xB = (y+0)*Width + (x-1);

xC = (y+1)*Width + (x-1);

xD = (y-1)*Width + (x+1);

xE = (y+0)*Width + (x+1);

xF = (y+1)*Width + (x+1);

yA = (y-1)*Width + (x-1);

yB = (y-1)*Width + (x+0);

yC = (y-1)*Width + (x+1);

yD = (y+1)*Width + (x-1);

yE = (y+1)*Width + (x+0);

yF = (y+1)*Width + (x+1);

//R

Sx =-*(src+3*xA+0)-*(src+3*xB+0)*2-*(src+3*xC+0)

+*(src+3*xD+0)+*(src+3*xE+0)*2+*(src+3*xF+0);

Sy =-*(src+3*yA+0)-*(src+3*yB+0)*2-*(src+3*yC+0)

+*(src+3*yD+0)+*(src+3*yE+0)*2+*(src+3*yF+0);

tmp = abs(Sx)+abs(Sy);

*(dest+3*CUR_POS(x,y,Width)+0) =RANGE(tmp);

//G

Sx =-*(src+3*xA+1)-*(src+3*xB+1)*2-*(src+3*xC+1)

+*(src+3*xD+1)+*(src+3*xE+1)*2+*(src+3*xF+1);

Sy =-*(src+3*yA+1)-*(src+3*yB+1)*2-*(src+3*yC+1)

+*(src+3*yD+1)+*(src+3*yE+1)*2+*(src+3*yF+1);

tmp = abs(Sx)+abs(Sy);

*(dest+3*CUR_POS(x,y,Width)+1) =RANGE(tmp);

//B

Sx =-*(src+3*xA+2)-*(src+3*xB+2)*2-*(src+3*xC+2)

+*(src+3*xD+2)+*(src+3*xE+2)*2+*(src+3*xF+2);

Sy =-*(src+3*yA+2)-*(src+3*yB+2)*2-*(src+3*yC+2)

+*(src+3*yD+2)+*(src+3*yE+2)*2+*(src+3*yF+2);

tmp = abs(Sx)+abs(Sy);

*(dest+3*CUR_POS(x,y,Width)+2) =RANGE(tmp);

}

voidGraphEdgeHandle(unsigned char *src, unsigned char *dest, unsigned int Width,unsigned int Height)

{

unsigned int C, U, D, R, L;

int x, y, tmp;

for(y = 0; y < Height; y++)

{

for(x = 0; x < Width; x++)

{

C = CUR_POS(x,y,Width);

(0 == x)? (L = C):( L = y*Width + (x-1) );

(Width-1 == x)? (R = C):( R = y*Width + (x+1) );

(0 == y)? (U = C):( U = (y-1)*Width + x );

(Height-1 == y)? (D = C):( D =(y+1)*Width + x );

tmp =*(src+3*C+0)*(-4)

+*(src+3*L+0)*1

+*(src+3*R+0)*1

+*(src+3*U+0)*1

+*(src+3*D+0)*1;

if(tmp < 0) tmp = 0;

if(tmp > 255) tmp = 255;

*(dest+3*C+0) = tmp;

tmp = *(src+3*C+1)*(-4)

+*(src+3*L+1)*1

+*(src+3*R+1)*1

+*(src+3*U+1)*1

+*(src+3*D+1)*1;

if(tmp < 0) tmp = 0;

if(tmp > 255) tmp = 255;

*(dest+3*C+1) = tmp;

tmp = *(src+3*C+2)*(-4)

+*(src+3*L+2)*1

+*(src+3*R+2)*1

+*(src+3*U+2)*1

+*(src+3*D+2)*1;

if(tmp < 0) tmp = 0;

if(tmp > 255) tmp = 255;

*(dest+3*C+2) = tmp;

}

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