霍夫变换

最新推荐文章于 2012-10-17 10:44:38 发布

原创最新推荐文章于 2012-10-17 10:44:38 发布 · 4.8k 阅读

9 ·

CC 4.0 BY-SA版权

文章标签：

#math.h #interface #im #file #class #c

图像处理专栏收录该内容

7 篇文章

订阅专栏

本文介绍了一种使用霍夫变换进行边缘检测的方法，并提供了具体的C++实现代码。通过对图像中的边缘点进行连接，实现了直线的检测。代码中详细展示了如何计算累加器计数、累加器排序以及如何连接边缘。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

霍夫变换，关于理论就不说了。我这里用到它的边缘点的连接。下面给出了代码的实现，本次代码因为时间的原因，写得很不规范。cpp文件如下：

// HoughTransform.cpp: implementation of the CHoughTransform class. // ////////////////////////////////////////////////////////////////////// #include "stdafx.h" #include "MyDIP.h" #include "HoughTransform.h" #include "math.h" #ifdef _DEBUG #undef THIS_FILE static char THIS_FILE[]=__FILE__; #define new DEBUG_NEW #endif ////////////////////////////////////////////////////////////////////// // Construction/Destruction ////////////////////////////////////////////////////////////////////// CHoughTransform::CHoughTransform() { m_nLineAngleMix=-90; //直线角度的范围 m_nLineAngleMax=90; m_nLineDistMix=-256; //直线距离的范围 m_nLineDistMax=256; m_nLineAngleNum=36; //步长的个数 int nStart=m_nLineAngleMix; int nStep=(m_nLineAngleMax-m_nLineAngleMix)/m_nLineAngleNum; //步长数 for(int i=0;i<m_nLineAngleNum;i++,nStart+=nStep) { m_nLineAngle1[i]=nStart; //每个步长所对应的范围 m_nLineAngle2[i]=nStart+nStep; m_nLineAngleM[i]=(m_nLineAngle1[i]+m_nLineAngle2[i])/2; //每个步长对应的中点 } m_nLineDistNum=64; //步长的个数 nStart=m_nLineDistMix; nStep=(m_nLineDistMax-m_nLineDistMix)/m_nLineDistNum; for(i=0;i<m_nLineDistNum;i++,nStart+=nStep) { m_nLineDist1[i]=nStart; m_nLineDist2[i]=nStart+nStep; m_nLineDistM[i]=(m_nLineDist1[i]+m_nLineDist2[i])/2; } m_nAddNum=6; //取几个累加器 } CHoughTransform::~CHoughTransform() { } //给定直接的标准式,画一条直接 //nXMin,nXMax表示该段直线的最小、最大X坐标 void CHoughTransform::DrawLine(CClientDC &dc, int nLineAngle, int nLineDist, int nXMin, int nXMax, int nYMin, int nYMax) {//先计算两个点的坐标 CPoint p1,p2; if(nLineAngle>-10&&nLineAngle<10) {//如果夹角为零,说明是平行于Y方向的一条直线 p1.x=nXMin; p1.y=nYMin; p2.x=nXMin; p2.y=nYMax; } else if(nLineAngle<-80||nLineAngle>80) { p1.x=nXMin; p1.y=nYMin; p2.x=nXMax; p2.y=nYMin; } else { p1.x=nXMin; p1.y=(long)((nLineDist-p1.x*cos(nLineAngle*PI/180))/sin(nLineAngle*PI/180)); if(p1.y>nYMax||p1.y<nYMin) {//点越界需要重新计算 if(p1.y<nYMin) p1.y=nYMin; else p1.y=nYMax; if(nLineAngle==90||nLineAngle==-90) p1.x=nXMin; else p1.x=(long)((nLineDist-p1.y*sin(nLineAngle*PI/180))/cos(nLineAngle*PI/180)); } p2.x=nXMax; p2.y=(long)((nLineDist-p2.x*cos(nLineAngle*PI/180))/sin(nLineAngle*PI/180)); if(p2.y>nYMax||p2.y<nYMin) {//点越界需要重新计算 if(p2.y>nYMax) p2.y=nYMax; else p2.y=nYMin; if(nLineAngle==90||nLineAngle==-90) p2.x=nXMax; else p2.x=(long)((nLineDist-p2.y*sin(nLineAngle*PI/180))/cos(nLineAngle*PI/180)); } } //对p1,p2放到图的中央 /* p1.x+=128; p1.y+=128; p2.x+=128; p2.y+=128; */ //画线p1,p2 dc.SetROP2(R2_BLACK); dc.MoveTo(p1); dc.LineTo(p2); } //对于每个点计算累加器计数 void CHoughTransform::ComputeAddCount() { double nDist1=0,nDist2=0; memset(m_nFinalLineAngle,0,LINENUMBER*sizeof(int)); memset(m_nFinalLineDist,0,LINENUMBER*sizeof(int)); memset(m_nFinalLineX1,0,LINENUMBER*sizeof(int)); memset(m_nFinalLineX2,0,LINENUMBER*sizeof(int)); memset(m_nFinalLineY1,0,LINENUMBER*sizeof(int)); memset(m_nFinalLineY2,0,LINENUMBER*sizeof(int)); for(int m=0;m<LINENUMBER;m++) for(int n=0;n<LINENUMBER;n++) { m_nAddCount[m][n]=0; m_nLineX1[m][n]=256; m_nLineY1[m][n]=256; m_nLineX2[m][n]=0; m_nLineY2[m][n]=0; } for(int i=0;i<m_nPointNum;i++) { for(int j=0;j<m_nLineAngleNum;j++) { nDist1=m_PCoord[i].x*cos(m_nLineAngleM[j]*PI/180)+ m_PCoord[i].y*sin(m_nLineAngleM[j]*PI/180); //nDist2=m_PCoord[i].x*cos(m_nLineAngle2[j]*PI/180)+ //m_PCoord[i].y*sin(m_nLineAngle2[j]*PI/180); //计算最接近的距离 for(int k=0;k<m_nLineDistNum;k++) { if(nDist1>=m_nLineDist1[k]&&nDist1<m_nLineDist2[k] //||nDist2>=m_nLineDist1[k]&&nDist2<m_nLineDist2[k] ) { ++m_nAddCount[j][k]; //计算线段的最小大边界 if(m_nLineX1[j][k]>m_PCoord[i].x) m_nLineX1[j][k]=m_PCoord[i].x; if(m_nLineX2[j][k]<m_PCoord[i].x) m_nLineX2[j][k]=m_PCoord[i].x; if(m_nLineY1[j][k]>m_PCoord[i].y) m_nLineY1[j][k]=m_PCoord[i].y; if(m_nLineY2[j][k]<m_PCoord[i].y) m_nLineY2[j][k]=m_PCoord[i].y; break; } } } } } //累加器排序 void CHoughTransform::SortAdd() {//找出累加器中最大的前m_nAddNum个,并把对应的下标存到m_nFinalLineAngle中 int nMax=0,nAngleIndex=0,nDistIndex=0; for(int k=0;k<m_nAddNum;k++) { nMax=0; for(int i=0;i<m_nLineAngleNum;i++) for(int j=0;j<m_nLineDistNum;j++) { if(nMax<m_nAddCount[i][j]) { nMax=m_nAddCount[i][j]; nAngleIndex=i; nDistIndex=j; } } m_nFinalLineAngle[k]=m_nLineAngleM[nAngleIndex]; m_nFinalLineDist[k]=m_nLineDistM[nDistIndex]; m_nFinalLineX1[k]=m_nLineX1[nAngleIndex][nDistIndex]; //线段的边界点 m_nFinalLineX2[k]=m_nLineX2[nAngleIndex][nDistIndex]; m_nFinalLineY1[k]=m_nLineY1[nAngleIndex][nDistIndex]; //线段的边界点 m_nFinalLineY2[k]=m_nLineY2[nAngleIndex][nDistIndex]; //把找到的最大值赋为-1，为下一次找最大值提供基 m_nAddCount[nAngleIndex][nDistIndex]=-1; } } //连接边缘 void CHoughTransform::ConnectEdge(CClientDC &dc) { for(int i=0;i<m_nAddNum;i++) { DrawLine( dc, m_nFinalLineAngle[i], m_nFinalLineDist[i], m_nFinalLineX1[i], m_nFinalLineX2[i], m_nFinalLineY1[i], m_nFinalLineY2[i]); } } //设置坐标点 void CHoughTransform::SetCoordinate(int nPointNum,CPoint p[]) { m_nPointNum=nPointNum; for(int i=0;i<nPointNum;i++) m_PCoord[i]=p[i]; }
.h文件如下：// HoughTransform.h: interface for the CHoughTransform class. // ////////////////////////////////////////////////////////////////////// #if !defined(AFX_HOUGHTRANSFORM_H__E7DC2F17_13C5_49C9_9522_F4F69EEF9D3D__INCLUDED_) #define AFX_HOUGHTRANSFORM_H__E7DC2F17_13C5_49C9_9522_F4F69EEF9D3D__INCLUDED_ #if _MSC_VER > 1000 #pragma once #endif // _MSC_VER > 1000 /********************************************** *类名:霍夫变换 *目的:连接离散点实现边缘 *作者:无忧狂澜 *日期:2010-01-29 **********************************************/ #define LINENUMBER 100 //直线的个数 #define POINTNUMBER 500 //边缘点的个数 #define PI 3.1415926 class CHoughTransform { public: CHoughTransform(); virtual ~CHoughTransform(); private: int m_nPointNum; //图中点的个数(灰度为0) CPoint m_PCoord[POINTNUMBER]; //点的坐标 //int m_nAddNum; //累加器的个数.对应的是直线步进的个数 //int m_nLineAngle[LINENUMBER]; //直线的标准式 //int m_nLineDist[LINENUMBER]; int m_nLineAngleMix; //直线角度的范围 int m_nLineAngleMax; int m_nLineDistMix; //直线距离的范围 int m_nLineDistMax; int m_nAddCount[LINENUMBER][LINENUMBER]; //累加器计数 int m_nLineAngleNum; //步长的个数 int m_nLineAngle1[LINENUMBER]; //每个步长所对应的范围 int m_nLineAngle2[LINENUMBER]; int m_nLineAngleM[LINENUMBER]; //每个步长对应的中点 int m_nLineDistNum; //步长的个数 int m_nLineDist1[LINENUMBER]; int m_nLineDist2[LINENUMBER]; int m_nLineDistM[LINENUMBER]; int m_nLineX1[LINENUMBER][LINENUMBER]; //线段的边界点 int m_nLineX2[LINENUMBER][LINENUMBER]; int m_nLineY1[LINENUMBER][LINENUMBER]; //线段的边界点 int m_nLineY2[LINENUMBER][LINENUMBER]; //int m_nAddThresh; //累加器的阈值 int m_nAddNum; //取几个累加器 int m_nFinalLineAngle[LINENUMBER]; //最终连接好的直线 int m_nFinalLineDist[LINENUMBER]; int m_nFinalLineX1[LINENUMBER]; //线段的边界点 int m_nFinalLineX2[LINENUMBER]; int m_nFinalLineY1[LINENUMBER]; //线段的边界点 int m_nFinalLineY2[LINENUMBER]; /* int m_nFinalLineNum; //最终得到的直线的个数 int m_nFinalLineAngle[LINENUMBER]; //直线的标准式 int m_nFinalLineDist[LINENUMBER]; */ public: int GetPointNum() {return m_nPointNum;} void SetPointNum(int nPointNum) {m_nPointNum=nPointNum;} void SetCoordinate(int nPointNum,CPoint p[]); //设置坐标点 /* int GetAddNum() {return m_nAddNum;} void SetAddNum(int AddNum) {m_nAddNum=AddNum;} int GetLineAngle(int nLineIndex) {return m_nLineAngle[nLineIndex];} void SetLineAngle(int nLineIndex,int nLineAngle) {m_nLineAngle[nLineIndex]=nLineAngle;} int GetLineDist(int nLineIndex) {return m_nLineDist[nLineIndex];} void SetLineDist(int nLineIndex,int nLineDist) {m_nLineDist[nLineIndex]=nLineDist;} int GetFinalLineNum() {return m_nFinalLineNum;} void SetFinalLineNum(int nFinalLineNum) {m_nFinalLineNum=nFinalLineNum;} int GetFinalLineAngle(int nLineIndex) {return m_nFinalLineAngle[nLineIndex];} void SetFinalLineAngle(int nLineIndex,int nFinalLineAngle) {m_nFinalLineAngle[nLineIndex]=nFinalLineAngle;} int GetFinalLineDist(int nLineIndex) {return m_nFinalLineDist[nLineIndex];} void SetFinalLineDist(int nLineIndex,int nFinalLineDist) {m_nFinalLineDist[nLineIndex]=nFinalLineDist;} */ //操作处理函数 public: void DrawLine(CClientDC &dc, int nLineAngle, int nLineDist, int nXMin, int nXMax, int nYMin, int nYMax); //画一条直线 void ComputeAddCount(); //累加器计数 void SortAdd(); //累加器排序 void ConnectEdge(CClientDC &dc); //连接边缘 }; #endif // !defined(AFX_HOUGHTRANSFORM_H__E7DC2F17_13C5_49C9_9522_F4F69EEF9D3D__INCLUDED_)

有需要的朋友可以直接把上面的代码复制为两个文件。

霍夫变换，参数空间的分割步长是比较难的，要根据实际中边缘的方向及位置来设置。下图为处理前的图像：