检测直线（Line）并按倾斜角度进行校正、画线、画延长线

int main(int argc, char** argv)  

{  

    double degree;  

    double sum=0.0;  

    int m=0;  

    const char* filename = "c:\2.jpg";  

    IplImage* src = cvLoadImage( filename, 0 );  

    IplImage* dst;  

    IplImage* color_dst;  

    CvMemStorage* storage = cvCreateMemStorage(0);  

    CvSeq* lines = 0;  

    int i;  

    if( !src )  

    {  

        return -1;  

    }  

    dst = cvCreateImage( cvGetSize(src), 8, 1 );  

    color_dst = cvCreateImage( cvGetSize(src), 8, 3 );  

    cvCanny( src, dst, 50, 200, 3 );  

    cvCvtColor( dst, color_dst, CV_GRAY2BGR );  

    lines = cvHoughLines2(dst, storage, CV_HOUGH_PROBABILISTIC, 1, CV_PI/180, 200, 50, 10);  

    double k;  

    for (i = 0; i < lines->total/*/20*/; i++)  

    {  

        CvPoint* line = (CvPoint*)cvGetSeqElem(lines, i);  

        if (fabs(line[0].x-line[1].x)>src->width/10 &&  fabs(line[0].y-line[1].y)<4)  //只检测近似水平的线，并且长度不能太短  

        {  

           cvLine(color_dst, line[0], line[1], CV_RGB(255, 0, 0), 3, CV_AA, 0);  

           double k=(line[0].y-line[1].y)/(line[0].x-line[1].x+0.000001);//不加0.000001 会变成曲线，斜率可能为0，即e.x-s.x可能为0  

           degree=atan(k)*180/3.1415926;  

           sum+=degree;  

           m++;  

          // break;  

        }  

    }  

    cvSaveImage("c:\hualine19.jpg",color_dst);  

    //新加的根据角度进行调整  

    degree=sum/m;  

    int center[2]={0,0};      

    center[0]=src->width/2;//这两句可以设置旋转中心的坐标  

    center[1]=src->height/2;  

//  cvSaveImage("c:\srccopy000.jpg",src);  

    myRotate(src,0,0, /*- */degree,center);//对原图像按倾斜角度进行旋转  

    cvSaveImage("c:\line.jpg",src);  

return 0;  

}  

// Line.cpp : Defines the entry point for the console application.  

//  

#include "stdafx.h"  

#include "cv.h"  

#include "highgui.h"  

int main(int argc, char* argv[])  

{  

    IplImage * picture , * gray, *dst;  

    picture=cvLoadImage("pi3.jpg",1);  

    gray = cvCreateImage(cvSize(picture->width,picture->height),IPL_DEPTH_8U,1);  

    cvCvtColor(picture,gray,CV_BGR2GRAY);  

    dst = cvCreateImage(cvSize(picture->width,picture->height),IPL_DEPTH_8U,1);  

    int w=picture->width;  

    int h=picture->height;     

    cvThreshold(gray,dst,220,255,CV_THRESH_BINARY);   

    cvSaveImage("dst.jpg",dst);  

    int i,j;  

    int flag1,flag2,flag3;  

    flag1=0;  

    flag2=0;  

    flag3=1;  

    int LineBytes=(w*8+31)/32*4;  

    int m=0;  

    uchar *pdata=(uchar *)dst->imageData;  

    for(j=0;j<h;j++)  

    {  

        for(i=0;i<w;i++)  

        {     

            if( flag1 == 0 && flag2 ==0)  

            {  

                if(pdata[LineBytes*j +i] == 0)  

                {                 

                    if (m%2==0 )  

                    {  

                        cvLine(picture,cvPoint(0,j-1),cvPoint(w,j-1),cvScalar(0,0,0),1);  

                        m++;  

                    }  

                    //cvSaveImage("pi1.jpg",picture);  

                    flag2=1;  

                    flag1=1;  

                    break;  

                }  

            }  

            else  

            {  

                if (pdata[LineBytes*j +i] == 255)  

                {  

                    flag2=0;  

                //  m++;  

                }  

                else  

                {  

                    flag2=1;  

                    break;  

                }  

            }  

        }  

        if (flag1 ==1 && flag2 ==0)  

        {  

            flag1 = 0;  

            flag2 = 0;  

            //m++;  

            if (m%2)  

            {  

                cvLine(picture,cvPoint(0,j+1),cvPoint(w,j+1),cvScalar(0,0,255),1);  

                //m++;  

            }  

            j=j+4;  

        }  

    }     

    cvSaveImage("pi2.jpg",picture);  

    return 0;  

}  

// Line.cpp : Defines the entry point for the console application.  

//  

#include "stdafx.h"  

#include "cv.h"  

#include "highgui.h"  

void OnDrawDotline(CvPoint s, CvPoint e,IplImage *workimg)  

{  

    CvPoint pa,pb;  

    double k=(s.y-e.y)/(s.x-e.x+0.000001);//不加0.000001 会变成曲线，斜率可能为0，即e.x-s.x可能为0  

    double h=workimg->height,w=workimg->width;      

    pa.x=w;  

    pa.y=s.y+k*(w-s.x);   

    cvLine(workimg,e,pa,CV_RGB(0,255,255), 2, CV_AA, 0 );   //向右画线  

    pb.y=e.y-k*e.x;  

    pb.x=0;  

    cvLine(workimg,pb,s,CV_RGB(0,0,255), 2, CV_AA, 0 ); //向左画线  

}  

int main(int argc, char* argv[])  

{  

    IplImage * picture , * gray, *dst;  

    picture=cvLoadImage("3.jpg",1);  

    gray = cvCreateImage(cvSize(picture->width,picture->height),IPL_DEPTH_8U,1);  

    cvCvtColor(picture,gray,CV_BGR2GRAY);  

    dst = cvCreateImage(cvSize(picture->width,picture->height),IPL_DEPTH_8U,1);  

    int w=picture->width;  

    int h=picture->height;     

    cvThreshold(gray,dst,220,255,CV_THRESH_BINARY);   

    cvSaveImage("dst.jpg",dst);  

    cvLine(picture,cvPoint(20,50),cvPoint(60,40),CV_RGB(255,0,0),3);  

    OnDrawDotline(cvPoint(20,50), cvPoint(60,40),picture);  

    cvSaveImage("pi2.jpg",picture);  

    return 0;  

}