【OpenCV学习】cvseqpartition序列分类

作者：gnuhpc
出处：http://www.cnblogs.com/gnuhpc/

#include "cxcore.h"

#include "highgui.h"

#include <stdio.h>



CvSeq* point_seq = 0;

IplImage* canvas = 0;

CvScalar* colors = 0;

int pos = 10;



int is_equal( const void* _a, const void* _b, void* userdata )

{

CvPoint a = *(const CvPoint*)_a;

CvPoint b = *(const CvPoint*)_b;

double threshold = *(double*)userdata;

return (double)(a.x - b.x)*(a.x - b.x) + (double)(a.y - b.y)*(a.y - b.y) <= threshold;

}



void on_track( int pos )

{

CvSeq* labels = 0; //声明输出标签

double threshold = pos*pos; //定义阈值为pos^2

int i, class_count = cvSeqPartition( point_seq, 0, &labels, is_equal, &threshold );

//对point_seq点序列拆分为等效的类，条件是(Ax-Bx)^2+(Ay-By)^2<=pos^2

//含义为两点相差距离小于pos的属于一类

printf("%4d classes/n", class_count );

//打印出分了几类

cvZero( canvas );



for( i = 0; i < labels->total; i++ )

{//取点、取颜色，画圆,你可以用按任意键的方式一个点一个点的画

CvPoint pt = *(CvPoint*)cvGetSeqElem( point_seq, i );

CvScalar color = colors[*(int*)cvGetSeqElem( labels, i )];

cvCircle( canvas, pt, 1, color, -1 );

cvShowImage( "points", canvas );

cvWaitKey(0);

}





}



int main( int argc, char** argv )

{

CvMemStorage* storage = cvCreateMemStorage(0);//建立了一个存储器

point_seq = cvCreateSeq( CV_32SC2, sizeof(CvSeq), sizeof(CvPoint), storage );

//建立了一个32位整型序列

CvRNG rng = cvRNG(0xffffffff);//初始化随机数生成器



int width = 500, height = 500;//定义图像的长和宽

int i, count = 1000;//定义了两个计数器

canvas = cvCreateImage( cvSize(width,height), 8, 3 );

//设置图像，大小为500*500，色深8，三通道



colors = (CvScalar*)cvAlloc( count*sizeof(colors[0]) );

//分配1000个CvScalar大小的内存缓冲区

for( i = 0; i < count; i++ )

{

CvPoint pt;//设置一个点

int icolor;//定义颜色标的

pt.x = cvRandInt( &rng ) % width;//随机产生点的x坐标

pt.y = cvRandInt( &rng ) % height;//随机产生点的y坐标

cvSeqPush( point_seq, &pt );//添加这个点到序列的尾部

icolor = cvRandInt( &rng ) +0xa0a0a0a0 ;

//用随机的方法给颜色标的一个基准，后边加的那个数字是可以任意的。

colors[i] = CV_RGB(icolor & 255, (icolor >> 8)&255, (icolor >> 16)&255);

//把这个点的颜色完全写入标量容器colors中

}



cvNamedWindow( "points", 1 );//创建窗口

cvCreateTrackbar( "threshold", "points", &pos, 50, on_track );

//建立拖动条，名称为threshold，窗口的名字叫points，创建初始化值取自pos，

//回调函数名称为on_track

on_track(pos);//监视拖动条的改变并处理之

cvWaitKey(0);

return 0;

} 

作者：gnuhpc
出处：http://www.cnblogs.com/gnuhpc/