Hough检测直线,圆,椭圆的部分代码
深之JOHNCHEN
1.hough检测直线
typedef struct MAXVALUE{
int iDist;
int iAngle;
int iMax;
}MAXVALUE;
/*
* 检测直线
*/
void TraceBeeline(int ImageWidth,int ImageHeight,LPBYTE lpSrc,LPBYTE lpDest,int len)
{
// #define pi 3.1415927
int iMaxAngle = 90;
int iAngleNumber = 0;
//最大值
MAXVALUE MaxValue1;
memset(&MaxValue1,0,sizeof(MAXVALUE));
//循环变量
int i;
int j;
int off = 0;
int iMaxDistance = 0,iDistance = 0;
iMaxDistance = (int)sqrt(ImageWidth * ImageWidth + ImageHeight * ImageHeight);
int *lpTrans = new int[iMaxDistance * iMaxAngle];
memset(lpTrans,0,iMaxDistance * iMaxAngle * sizeof(int));
//去掉孤立点
for(j=1,off=0;j<ImageHeight-1;j++)
for(i=1;i<ImageWidth-1;i++,off)
{
if(1==lpSrc[off])
{
if(lpSrc[off-1]==0&&lpSrc[off+1]==0&&lpSrc[off-ImageWidth]==0&&lpSrc[off+ImageWidth]==0 /
lpSrc[off-ImageWidth-1]==0&&lpSrc[off-ImageWidth+1]==0&&lpSrc[off+ImageWidth-1]==0&&lpSrc[off+ImageWidth+1]==0)
lpSrc[off]=0;
}
}
//////////////////////////////
for(j=0;j<ImageHeight;j++)
for(i=0;i<ImageWidth;i++)
{
off = j * ImageWidth + i;
if(1==lpSrc[off])
{
for(iAngleNumber=0;iAngleNumber<iMaxAngle;iAngleNumber++)
{
iDistance = (int)fabs(i * cos(iAngleNumber * 2 * PI/180.0) + j * sin(iAngleNumber * 2 * PI/180.0));
if(iDistance>=0&&iDistance<iMaxDistance)
lpTrans[iDistance * iMaxAngle + iAngleNumber]++;
}
}
}
//找到最大值
for(i = 0;i < iMaxDistance;i++)
for(iAngleNumber=0;iAngleNumber<iMaxAngle;iAngleNumber++)
{
if(lpTrans[i * iMaxAngle + iAngleNumber]>MaxValue1.iMax)
{
MaxValue1.iMax = (int)lpTrans[i * iMaxAngle + iAngleNumber];
MaxValue1.iAngle = iAngleNumber;
MaxValue1.iDist = i;
}
}
//
for(j=0;j<ImageHeight;j++)
for(i=0;i<ImageWidth;i++)
{
off = j * ImageWidth + i;
iDistance = (int)fabs(i * cos(iAngleNumber * 2 * PI/180.0) + j * sin(iAngleNumber * 2 * PI/180.0));
if(iDistance == MaxValue1.iMax)
lpDest[off]=1;
}
if(lpTrans)
{
delete lpTrans;
lpTrans = NULL;
}
}
2.hough检测圆
根据园的方程（x－a）×（x－a）＋（y－b）×（y－b）＝R×R，将参数空间增加到a，b，R三维空间.
常用的hough变换计算量太大,然而随机hough变换虽然计算量相对小点,但是准确率没有前者高.现在使用
一种改进的方法:提取边缘图像,然后边缘跟踪,在边缘曲线上进行hough变换检测圆.
double x=0.0,y=0.0,x0=0.0,y0=0.0,cc=0.0,ss=0.0,temp1,temp2;
int aa=0,bb=0,rr=0,saveaa=0,savebb=0,saverr=0,savexx0=0,saveyy0=0,saveQ=0;
int pos = ptNumber/3;
int i = 0,off = 0,k = 0,iBaseFlag = 100,jj = 0;
int tt = 0,m=0,n=0;
int firstBase = 5;
int secendBase = (2*firstBase+1);
int aaBase = (R.right+R.left)/2 - firstBase,bbBase = (R.bottom+R.top)/2 -firstBase;
LONG minrr = 0;
minrr = (R.right - R.left)>(R.bottom - R.top)?(R.bottom - R.top):(R.right - R.left);
int memsize = (int)(minrr+2*firstBase) * secendBase *secendBase;
BYTE * lpabr = new BYTE[memsize];
memset(lpabr,0,sizeof(BYTE)*memsize);
int maxcount = -1;
/* 局部hough变换检测圆曲线段的一部分*/
for(k=0;k<ptNumber;k+=pos)
{
for(aa=(int)(R.left+R.right)/2 - firstBase;aa<=(int)(R.left+R.right)/2 + firstBase;aa++)
{
if(aa<0)
continue;
if(aa>ImageWidth)
break;
for(bb=(int)(R.top+R.bottom)/2 -firstBase;bb<=(int)(R.top+R.bottom)/2 + firstBase;bb++)
{
if(bb<0)
continue;
if(bb>ImageHeight)
break;
temp1 = (pt[k].x-aa)*(pt[k].x-aa) + (pt[k].y-bb)*(pt[k].y-bb);
rr = (int)sqrt(temp1);
if(rr>=10&&rr<=(int)(minrr/2) + firstBase)
lpabr[rr*secendBase*secendBase+(aa-aaBase)*secendBase+(bb-bbBase)]++;
}
}
}
for(rr=10;rr<=(int)(minrr/2) + firstBase;rr++)
for(aa=(int)(R.left+R.right)/2 - firstBase;aa<=(int)(R.left+R.right)/2 + firstBase;aa++)
{
if(aa<0)
continue;
if(aa>ImageWidth)
break;
for(bb=(int)(R.top+R.bottom)/2 - firstBase;bb<=(int)(R.top+R.bottom)/2 + firstBase;bb++)
{
if(bb<0)
continue;
if(bb>ImageHeight)
break;
if(maxcount<lpabr[rr*secendBase*secendBase+(aa-aaBase)*secendBase+(bb-bbBase)])
{
maxcount = lpabr[rr*secendBase*secendBase+(aa-aaBase)*secendBase+(bb-bbBase)];
saverr = rr;
saveaa = aa;
savebb = bb;
}
}
}
if(maxcount>=4)
{
//记录保存中心,半经
saverr = rr;
saveaa = aa;
savebb = bb;
}
3.hough变换检测椭圆的程序
一个MATLAB程序，有些地方你自己修改以下就可以了。
[row col]=size(fedge);
minofa=a;
maxofa=round(row/2);
minofy0=round(col/2)-30;
maxofy0=round(col/2)+30;
minofb=round(col/2)-60;
maxofb=round(col/2);
maxofx=round(row/2);
scalor=4;
H=zeros(floor((maxofa-minofa)/scalor)+1,floor((maxofa-minofa)/scalor)+1,...
floor((maxofy0-minofy0)/scalor)+1,floor((maxofb-minofb)/scalor)+1);
for x=1:maxofx
for y=1:col
temp=fedge(x,y);
if temp==255
for a=minofa:scalor:maxofa
for x0=a:scalor:maxofa
for b=minofb:scalor:maxofb
for y0=minofy0:scalor:maxofy0
temp=((y-y0)/b)^2+((x-x0)/a)^2;
if abs(temp-1)<=0.01
xtemp=floor((x0-minofa)/scalor)+1;
atemp=floor((a-minofa)/scalor)+1;
ytemp=floor((y0-minofy0)/scalor)+1;
btemp=floor((b-minofb)/scalor)+1;
H(xtemp,atemp,ytemp,btemp)=H(xtemp,atemp,ytemp,btemp)+1;
end
end
end
end
end
end
end
end
maxofH=max(max(max(max(H))));
for i=1:floor((maxofa-minofa)/scalor)+1
for j=1:floor((maxofa-minofa)/scalor)+1
for m=1:floor((maxofy0-minofy0)/scalor)+1
for n=1:floor((maxofb-minofb)/scalor)+1
temp=H(i,j,m,n);
if temp==maxofH
xtemp=i;
atemp=j;
ytemp=m;
btemp=n;
break;
end
end
end
end
end
x0=(xtemp-1)*scalor+minofa;
a=(atemp-1)*scalor+minofa;
y0=(ytemp-1)*scalor+minofy0;
b=(btemp-1)*scalor+minofb;
figure;
imshow(fedge,[]);
hold on;
plot(y0,x0,'r+');
t=0:pi/180:2*pi;
plot(y0+b*sin(t),x0+a*cos(t),'r-');
hold off;