使用opencv查找没有角的矩形 [英] Find rectangles without corners using opencv

问题描述

我有一个要查找轮廓的图像，但是图像中的轮廓"没有角.我可以使用一些技巧来帮助找到此图像中的线所隐含的矩形吗?我曾考虑过将所有线延长成角，但担心线与其他轮廓线相交以及如何确定我感兴趣的相交点.我对opencv并不陌生，对图像处理也不了解.感谢您提供的任何帮助.

I have an image where I want to find contours but the "contours" in my image don't have corners. Are there some tricks I can use to help find the rectangles that are implied by the lines in this image? I thought about extending all the lines to form the corners but I worry about lines intersecting from other contours and how to determine which intersections I'm interested in. I'm very new to opencv and I don't know much about image processing. Thank you for any help you can give.

推荐答案

我最终实现了自己的解决方案.它不是很优雅，但是可以完成工作.我将有兴趣听到有关改进的信息. HoughLines2在寻找线段时并不总是给我带来很好的结果，并且我不得不在不同的情况下大为改变阈值.取而代之的是，我选择了FindCountours，在其中我用两个元素绘制了轮廓，应该保证我有1像素宽的线.找到线条后，我遍历了线条并找出了矩形.

I ended up implementing my own solution. It isn't very graceful but it gets the job done. I would be interested in hearing about improvements. HoughLines2 didn't always give me good results for finding line segments and I had to mess around with the threshold value a lot for different scenarios. Instead I opted for FindCountours where I took contours with two elements, I should be guaranteed 1 pixel wide lines. After finding the lines I iterated through them and traced them out to find the rectangles.

点是线端点的* CvSeq

Where points is a *CvSeq of the line endpoints

while(points->total>0){
  if(p1.x==-1&&p1.y==-1){
     cvSeqPopFront(points,&p1);
     cvSeqPopFront(points,&p2);
  }

  if((pos=findClosestPoint(&p1,&p2, points,maxDist))>=0){  
     p3 = (CvPoint*)cvGetSeqElem( points,pos );
     pos2 = (pos%2==0)?pos+1:pos-1; //lines are in pairs of points
     p4 = (CvPoint*)cvGetSeqElem( points,pos2 );

     if(isVertical(&p1,&p2) && isHorizontal(p3,p4)){
        printf("found Corner %d %d\n",p2.x,p3->y);
     } else if(isHorizontal(&p1,&p2) && isVertical(p3,p4) ){
        printf("found Corner %d %d\n",p3->x,p2.y);
     }

     memcpy(&p1,p3,sizeof(CvPoint));
     memcpy(&p2,p4,sizeof(CvPoint));
     cvSeqRemove(points, (pos>pos2)?pos:pos2);
     cvSeqRemove(points, (pos>pos2)?pos2:pos);
  } else {
     p1.x=-1;
     p1.y=-1;
  }
}

int findClosestPoint (CvPoint *p1, CvPoint *p2, CvSeq *points, int maxDist) {  
   int ret = -1,i;
   float dist, minDist = maxDist;
   CvPoint* test;
   int (*dirTest)(CvPoint *,CvPoint *);

   if(isVertical(p1,p2)){ //vertical line
      if(p2->y > p1->y) {//going down
         dirTest = isBelow;
      } else { // going up
         dirTest = isAbove;
      }
   } else if (isHorizontal(p1,p2)){ //horizontal line
      if(p2->x > p1->x) {//going right
         dirTest = isRight;
      } else { //going left
         dirTest = isLeft;
      }
   }

   for( i = 0; i < points->total; i++ )
   {
      test = (CvPoint*)cvGetSeqElem( points, i );
      if(dirTest(p2,test)){ //only test points in the region we care about
         dist = sqrt(pow(test->x - p2->x,2)+pow(test->y - p2->y,2));
         if(dist<minDist){
            minDist = dist;
            ret = i;
         }
      }
   } 
   return ret;
}

int isVertical(CvPoint *p1, CvPoint *p2){
   return p1->x == p2->x;
}
int isHorizontal(CvPoint *p1, CvPoint *p2){
   return p1->y == p2->y;
}
int isRight(CvPoint *pt1, CvPoint *pt2){
   return pt2->x > pt1->x;
}
int isLeft(CvPoint *pt1, CvPoint *pt2){
   return pt2->x < pt1->x;
}
int isBelow(CvPoint *pt1, CvPoint *pt2){
   return pt2->y > pt1->y;
}
int isAbove(CvPoint *pt1, CvPoint *pt2){
   return pt2->y < pt1->y;
}

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