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【opencv】图像细化

發布時間：2024/4/17 编程问答 51 豆豆

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【opencv】圖像細化

2014-02-17 21:03?5404人閱讀?評論(14)?收藏?舉報 ?分類： ? opencv（1）?

???? 在我們進行圖像處理的時候，有可能需要對圖像進行細化，提取出圖像的骨架信息，進行更加有效的分析。

???? 圖像細化（Image Thinning），一般指二值圖像的骨架化（Image Skeletonization）的一種操作運算。

???? 所謂的細化就是經過一層層的剝離，從原來的圖中去掉一些點，但仍要保持原來的形狀，直到得到圖像的骨架。骨架，可以理解為圖象的中軸。

???? 好的細化算法一定要滿足：

收斂性；
保證細化后細線的連通性；
保持原圖的基本形狀；
減少筆畫相交處的畸變；
細化結果是原圖像的中心線；
細化的快速性和迭代次數少；

????這里，我們對“Zhang并行快速細化算法”進行了實現（注意，該算法為并行算法，而我們在實現過程中并沒有并行化處理，所以，效率并沒有達到最好）。

????參考資料

細化算法
論文 A fast parallel algorithm for thinning digital patterns [cpp]?view plain?copy ?
#include?<opencv2/opencv.hpp>??
#include?<iostream>??
#include?<vector>??
#include?<limits>??
??
using?namespace?cv;??
using?namespace?std;??
??
/**?
?*?@brief?對輸入圖像進行細化?
?*?@param[in]?src為輸入圖像,用cvThreshold函數處理過的8位灰度圖像格式，元素中只有0與1,1代表有元素，0代表為空白?
?*?@param[out]?dst為對src細化后的輸出圖像,格式與src格式相同，調用前需要分配空間，元素中只有0與1,1代表有元素，0代表為空白?
?*?@param[in]?maxIterations限制迭代次數，如果不進行限制，默認為-1，代表不限制迭代次數，直到獲得最終結果?
?*/??
void?thinImage(IplImage*?src,IplImage*?dst,int?maxIterations?=?-1?)??
{??
????CvSize?size?=?cvGetSize(src);??
????cvCopy(src,dst);//將src中的內容拷貝到dst中??
????int?count?=?0;??//記錄迭代次數??
????while?(true)??
????{??
????????count++;??
????????if(maxIterations!=-1?&&?count?>?maxIterations)?//限制次數并且迭代次數到達??
????????????break;??
????????//std::cout?<<?count?<<?'?';輸出迭代次數??
????????vector<pair<int,int>?>?mFlag;?//用于標記需要刪除的點??
????????//對點標記??
????????for?(int?i=0;?i<size.height;?++i)??
????????{??
????????????for?(int?j=0;?j<size.width;?++j)??
????????????{??
????????????????//如果滿足四個條件，進行標記??
????????????????//??p9?p2?p3??
????????????????//??p8?p1?p4??
????????????????//??p7?p6?p5??
????????????????int?p1?=?CV_IMAGE_ELEM(dst,uchar,i,j);??
????????????????int?p2?=?(i==0)?0:CV_IMAGE_ELEM(dst,uchar,i-1,j);??
????????????????int?p3?=?(i==0?||?j==size.width-1)?0:CV_IMAGE_ELEM(dst,uchar,i-1,j+1);??
????????????????int?p4?=?(j==size.width-1)?0:CV_IMAGE_ELEM(dst,uchar,i,j+1);??
????????????????int?p5?=?(i==size.height-1?||?j==size.width-1)?0:CV_IMAGE_ELEM(dst,uchar,i+1,j+1);??
????????????????int?p6?=?(i==size.height-1)?0:CV_IMAGE_ELEM(dst,uchar,i+1,j);??
????????????????int?p7?=?(i==size.height-1?||?j==0)?0:CV_IMAGE_ELEM(dst,uchar,i+1,j-1);??
????????????????int?p8?=?(j==0)?0:CV_IMAGE_ELEM(dst,uchar,i,j-1);??
????????????????int?p9?=?(i==0?||?j==0)?0:CV_IMAGE_ELEM(dst,uchar,i-1,j-1);??
??
????????????????if?((p2+p3+p4+p5+p6+p7+p8+p9)>=2?&&?(p2+p3+p4+p5+p6+p7+p8+p9)<=6)??
????????????????{??
????????????????????int?ap=0;??
????????????????????if?(p2==0?&&?p3==1)?++ap;??
????????????????????if?(p3==0?&&?p4==1)?++ap;??
????????????????????if?(p4==0?&&?p5==1)?++ap;??
????????????????????if?(p5==0?&&?p6==1)?++ap;??
????????????????????if?(p6==0?&&?p7==1)?++ap;??
????????????????????if?(p7==0?&&?p8==1)?++ap;??
????????????????????if?(p8==0?&&?p9==1)?++ap;??
????????????????????if?(p9==0?&&?p2==1)?++ap;??
??????????????????????
????????????????????if?(ap==1)??
????????????????????{??
????????????????????????if?(p2*p4*p6==0)??
????????????????????????{??
????????????????????????????if?(p4*p6*p8==0)??
????????????????????????????{??
????????????????????????????????//標記??
????????????????????????????????mFlag.push_back(make_pair(i,j));??
????????????????????????????}??
????????????????????????}??
????????????????????}??
????????????????}??
????????????}??
????????}??
??
????????//將標記的點刪除??
????????for?(vector<pair<int,int>?>::iterator?i=mFlag.begin();?i!=mFlag.end();?++i)??
????????{??
????????????CV_IMAGE_ELEM(dst,uchar,i->first,i->second)?=?0;??
????????}??
??
????????//直到沒有點滿足，算法結束??
????????if?(mFlag.size()==0)??
????????{??
????????????break;??
????????}??
????????else??
????????{??
????????????mFlag.clear();//將mFlag清空??
????????}??
??
????????//對點標記??
????????for?(int?i=0;?i<size.height;?++i)??
????????{??
????????????for?(int?j=0;?j<size.width;?++j)??
????????????{??
????????????????//如果滿足四個條件，進行標記??
????????????????//??p9?p2?p3??
????????????????//??p8?p1?p4??
????????????????//??p7?p6?p5??
????????????????int?p1?=?CV_IMAGE_ELEM(dst,uchar,i,j);??
????????????????if(p1!=1)?continue;??
????????????????int?p2?=?(i==0)?0:CV_IMAGE_ELEM(dst,uchar,i-1,j);??
????????????????int?p3?=?(i==0?||?j==size.width-1)?0:CV_IMAGE_ELEM(dst,uchar,i-1,j+1);??
????????????????int?p4?=?(j==size.width-1)?0:CV_IMAGE_ELEM(dst,uchar,i,j+1);??
????????????????int?p5?=?(i==size.height-1?||?j==size.width-1)?0:CV_IMAGE_ELEM(dst,uchar,i+1,j+1);??
????????????????int?p6?=?(i==size.height-1)?0:CV_IMAGE_ELEM(dst,uchar,i+1,j);??
????????????????int?p7?=?(i==size.height-1?||?j==0)?0:CV_IMAGE_ELEM(dst,uchar,i+1,j-1);??
????????????????int?p8?=?(j==0)?0:CV_IMAGE_ELEM(dst,uchar,i,j-1);??
????????????????int?p9?=?(i==0?||?j==0)?0:CV_IMAGE_ELEM(dst,uchar,i-1,j-1);??
??
????????????????if?((p2+p3+p4+p5+p6+p7+p8+p9)>=2?&&?(p2+p3+p4+p5+p6+p7+p8+p9)<=6)??
????????????????{??
????????????????????int?ap=0;??
????????????????????if?(p2==0?&&?p3==1)?++ap;??
????????????????????if?(p3==0?&&?p4==1)?++ap;??
????????????????????if?(p4==0?&&?p5==1)?++ap;??
????????????????????if?(p5==0?&&?p6==1)?++ap;??
????????????????????if?(p6==0?&&?p7==1)?++ap;??
????????????????????if?(p7==0?&&?p8==1)?++ap;??
????????????????????if?(p8==0?&&?p9==1)?++ap;??
????????????????????if?(p9==0?&&?p2==1)?++ap;??
??
????????????????????if?(ap==1)??
????????????????????{??
????????????????????????if?(p2*p4*p8==0)??
????????????????????????{??
????????????????????????????if?(p2*p6*p8==0)??
????????????????????????????{??
????????????????????????????????//標記??
????????????????????????????????mFlag.push_back(make_pair(i,j));??
????????????????????????????}??
????????????????????????}??
????????????????????}??
????????????????}??
????????????}??
????????}??
????????//刪除??
????????for?(vector<pair<int,int>?>::iterator?i=mFlag.begin();?i!=mFlag.end();?++i)??
????????{??
????????????CV_IMAGE_ELEM(dst,uchar,i->first,i->second)?=?0;??
????????}??
??
????????//直到沒有點滿足，算法結束??
????????if?(mFlag.size()==0)??
????????{??
????????????break;??
????????}??
????????else??
????????{??
????????????mFlag.clear();//將mFlag清空??
????????}??
????}??
}??
??
int?main(int?argc,?char*argv[])??
{??
????//獲取圖像??
????if?(argc!=2)??
????{??
????????cout?<<?"參數個數錯誤！"<<endl;??
????????return?-1;??
????}??
????IplImage?*pSrc?=?cvLoadImage(argv[1],CV_LOAD_IMAGE_GRAYSCALE);??
????if?(!pSrc)??
????{??
????????cout?<<?"讀取文件失敗！"?<<?endl;??
????????return?-1;??
????}??
????IplImage?*pTemp?=?cvCreateImage(cvGetSize(pSrc),pSrc->depth,pSrc->nChannels);??
????IplImage?*pDst?=?cvCreateImage(cvGetSize(pSrc),pSrc->depth,pSrc->nChannels);??
??????
????//將原圖像轉換為二值圖像??
????cvThreshold(pSrc,pTemp,128,1,CV_THRESH_BINARY);???
????//圖像細化??
????thinImage(pTemp,pDst);??
??
????for?(int?i=0;?i<pDst->height;?++i)??
????{??
????????for?(int?j=0;?j<pDst->width;?++j)??
????????{??
????????????if(CV_IMAGE_ELEM(pDst,uchar,i,j)==1)??
????????????????CV_IMAGE_ELEM(pDst,uchar,i,j)=?255;??
????????}??
????}??
??
????namedWindow("src",CV_WINDOW_AUTOSIZE);??
????namedWindow("dst",CV_WINDOW_AUTOSIZE);??
????cvShowImage("src",pSrc);??
????cvShowImage("dst",pDst);??
??
????waitKey(0);??
}??

??? 運行效果

1原圖像

2.運行效果

轉載于:https://www.cnblogs.com/donaldlee2008/p/5232035.html

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