车牌识别技术详解四--二值化找轮廓做分割得样本（车牌分割，验证码分割）

这一节，主要讲通过灰度化，自适应二值化，ROI找轮廓，轮廓筛选，ROI轮廓分割，自动割取样本；

如图：在车牌分割中应用比较广，大致思路可以看我的程序，具体细节可以针对不同的检测物体的大小以及背景更改。

#include <cv.h>
#include <highgui.h>
#include <cvaux.h>

using namespace std;
using namespace cv;

#define showSteps false
#define saveModel false

//定义文件夹下视频的数量
#define NumVideo 16

string getFilename(string s) {

	char sep = '/';
	char sepExt='.';

#ifdef _WIN32
	sep = '\\';
#endif

	size_t i = s.rfind(sep, s.length( ));
	if (i != string::npos) {
		string fn= (s.substr(i+1, s.length( ) - i));
		size_t j = fn.rfind(sepExt, fn.length( ));
		if (i != string::npos) {
			return fn.substr(0,j);
		}else{
			return fn;
		}
	}else{
		return "";
	}
}

void adaptiveThreshold(Mat input, Mat bin, int width, int height);

bool verifySizes(RotatedRect mr){

	float error=0.6;
	//Spain car plate size: 20*40 aspect 360
	float aspect=0.5;
	//Set a min and max area. All other patchs are discarded
	int min= 20*aspect*20; // minimum area 200
	int max= 50*aspect*50; // maximum area 1250
	//Get only patchs that match to a respect ratio.
	float rmin= aspect-aspect*error; //0.5-0.5*0.6 = 0.2
	float rmax= aspect+aspect*error; //0.8

	int area= mr.size.height * mr.size.width;
	float r= (float)mr.size.width / (float)mr.size.height;

	
	/*if(r<1)
	r= (float)mr.size.height / (float)mr.size.width;*/

	if(( area < min || area > max ) || ( r < rmin || r > rmax ) || (mr.size.height>=47 || mr.size.height<=26)||(mr.size.width<=9 || mr.size.width>=31)){
//	if( (mr.size.height>=45 || mr.size.height<=24)||(mr.size.width<=6 || mr.size.width>=27) ){
		return false;
	}else{
		return true;
	}
}

int main ( int argc, char** argv )
{
	//初始化一个视频文件捕捉器
	char *video_name = NULL;
	CvCapture* capture;
	video_name = (char*)malloc(500*sizeof(char)); //动态分配内存

	char *filename = NULL;
	filename=(char *)malloc(50*sizeof(char)); //动态分配内存

	for(int jj=1; jj<=NumVideo; jj++)
	{
		int i=0; //视频读取标志标志
		printf("\n第%d段视频\n",jj);

		sprintf_s(video_name, 500, "E:\\video\\%d.avi",jj);//保存的图片名
//		sprintf_s(video_name, 500, "I:\\ship\\%d.avi",jj);//保存的图片名
		capture = cvCaptureFromAVI(video_name);
		//	CvCapture* capture = cvCaptureFromAVI("..\\video\\4.avi");
		if( capture == NULL ){
			printf("视频文件打开失败！！");
			continue;
		}

		int frameH    = (int) cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_HEIGHT);
		int frameW    = (int) cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_WI