FindAngle

float FindAngle(const IplImage* rgb_img,int threshold,int hor)
{

float ret = -1.0; 
CvSize size = cvGetSize(rgb_img);
CvMemStorage* storage = cvCreateMemStorage(0);

IplImage* img_gray = cvCreateImage(size,IPL_DEPTH_8U,1);
IplImage* img_sobel_bw = cvCreateImage(size,IPL_DEPTH_8U,1);


cvCvtColor(rgb_img,img_gray,CV_BGR2GRAY);
cvSmooth(img_gray,img_gray,CV_MEDIAN);
GrayStretch(img_gray,img_gray);
//求边缘图
if(hor)
    ReturnSobelImage(img_gray,img_sobel_bw,0,1);
else
    ReturnSobelImage(img_gray,img_sobel_bw,1,0);



/*cvShowImage("img_sobel",img_sobel_bw);
cvWaitKey(0);*/

//利用哈弗变换求图中的直线
CvSeq* result = cvHoughLines2(
    img_sobel_bw,
    storage,
    CV_HOUGH_STANDARD,
    1,
    CV_PI/180,
    threshold);

if(result->total != 0)
{
    float* line = (float*)cvGetSeqElem(result,0);
    ret = (float)CV_PI/2 - line[1];
    //IplImage* img_draw = cvCloneImage(img_gray);
    //cvZero(img_draw);
    //for(int i=0;i<result->total;i++)
    //{
    //  float* l = (float*)cvGetSeqElem(result,i);
    //  cvLine(img_draw,cvPoint(0,l[0]/sin(l[1])),cvPoint(l[0]/cos(l[1]),0),cvScalar(255,255,255),1);
    //  /*CvPoint* line = (CvPoint*)cvGetSeqElem(result,i);
    //  cvLine(img_draw,line[0],line[1],cvScalar(255,255,255),1);*/
    //}
    //
    //cvShowImage("img_draw",img_draw);
    //cvWaitKey(0);
}
cvReleaseMemStorage(&storage);
cvReleaseImage(&img_gray);
cvReleaseImage(&img_sobel_bw);


return ret;

}