using openCV2.4.3 for Detect Rectangle

using openCV2.4.3 for Detect Rectangle

(제목이 문법이 맞는가 모르겠네~  for 빼는게 나아보이는데 )

openCV version : 2.4.3 using Visual studio 2010

소스코드 

001_DetectRectangle(opencv2.2).zip

002_DetectRectangle(opencv2.4.3).zip

003_DetectRectangle(opencv2.4.3)_newVersion.zip

#include 

#include 
#include 
#include 

using namespace std;
using namespace cv;

// example : Creating Bounding rotated boxes and ellipses for contours
// http://docs.opencv.org/doc/tutorials/imgproc/shapedescriptors/bounding_rotated_ellipses/bounding_rotated_ellipses.html

Mat src; Mat src_gray;
int thresh = 100;
int max_thresh = 255;
RNG rng(12345);

/// Function header
void thresh_callback(int, void* );
double angle( Point pt1, Point pt2, Point pt0 );;

/** @function main */
int main( int argc, char** argv )
{
	/// Load source image and convert it to gray
	//src = imread( argv[1], 1 );
	//Mat loadimage = imread( "rectangle.png" );	                         
	src = imread( "rectangle.png" );	                         

	/// Convert image to gray and blur it
	cvtColor( src, src_gray, CV_BGR2GRAY );
	blur( src_gray, src_gray, Size(3,3) );

	/// Create Window
	char* source_window = "Source";
	namedWindow( source_window, CV_WINDOW_AUTOSIZE );
	imshow( source_window, src );

	createTrackbar( " Threshold:", "Source", &thresh, max_thresh, thresh_callback );
	thresh_callback( 0, 0 );

	waitKey(0);
	return(0);
}

/** @function thresh_callback */
void thresh_callback(int, void* )
{
	Mat threshold_output;
	vector > contours;
	vector hierarchy;

	/// Detect edges using Threshold
	threshold( src_gray, threshold_output, thresh, 255, THRESH_BINARY );
	/// Find contours
	findContours( threshold_output, contours, hierarchy, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, Point(0, 0) );

	/// Find the rotated rectangles and ellipses for each contour
	vector minRect( contours.size() );
	vector minEllipse( contours.size() );

	for( int i = 0; i < contours.size(); i++ )
	{ 
		
		// Test contours
		vector approx;
		for (size_t i = 0; i < contours.size(); i++)
		{
			
			// approximate contour with accuracy proportional
			// to the contour perimeter
			approxPolyDP(Mat(contours[i]), approx, arcLength(Mat(contours[i]), true)*0.02, true);

			// Note: absolute value of an area is used because
			// area may be positive or negative - in accordance with the
			// contour orientation
			if (approx.size() == 4 && fabs(contourArea(Mat(approx))) > 1000 && isContourConvex(Mat(approx)) )
			{
				double maxCosine = 0;
				for (int j = 2; j < 5; j++){
					double cosine = fabs(angle(approx[j%4], approx[j-2], approx[j-1]));
					maxCosine = MAX(maxCosine, cosine);
				}
				if (maxCosine < 0.3){
					//squares.push_back(approx);
					minRect[i] = minAreaRect( Mat(contours[i]) );
				}
			}
		}

		//minRect[i] = minAreaRect( Mat(contours[i]) );
		if( contours[i].size() > 5 ) { 
			//minEllipse[i] = fitEllipse( Mat(contours[i]) ); 
		}
	}

	/// Draw contours + rotated rects + ellipses
	Mat drawing = Mat::zeros( threshold_output.size(), CV_8UC3 );
	for( int i = 0; i< contours.size(); i++ )
	{
		Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) );
		// contour
		//drawContours( drawing, contours, i, color, 1, 8, vector(), 0, Point() );
		// ellipse
		ellipse( drawing, minEllipse[i], color, 2, 8 );
		// rotated rectangle
		Point2f rect_points[4]; minRect[i].points( rect_points );
		for( int j = 0; j < 4; j++ )
			line( drawing, rect_points[j], rect_points[(j+1)%4], color, 1, 8 );
	}

	/// Show in a window
	namedWindow( "Contours", CV_WINDOW_AUTOSIZE );
	imshow( "Contours", drawing );
}

double angle( Point pt1, Point pt2, Point pt0 ) 
{
	double dx1 = pt1.x - pt0.x;
	double dy1 = pt1.y - pt0.y;
	double dx2 = pt2.x - pt0.x;
	double dy2 = pt2.y - pt0.y;
	return (dx1*dx2 + dy1*dy2)/sqrt((dx1*dx1 + dy1*dy1)*(dx2*dx2 + dy2*dy2) + 1e-10);
}

결과

01. 그림1

- 원본이미지

02. 그림2 - 기존에 코드를 사용하여 사각형을 검출

문제점 : Detection 사각형을 검출할때, 중복되어서 검출된 것을 모두 출력하게 된다. 

            그래서 groupRectangles() 함수를 사용하여서 해결을 하도록 하자. (다른방법을 써두된다.)

           본 포스팅의 코드에서는 아래의 결과가 나오는 코드가 압축파일로 올려짐, 즉 코드를 사용하지 않음

03. 그림3 

- groupRectangles() 를 사용하는것도 좋으나, 일단~ contours 를 이용하여서 모든 객체 검출

04. 그림4 

 - 처음에 사용한 사각형 검출을 이용하여 사각형일 경우에 vector list에 담도록 한다. 

Think

 - MQ :  생각해보니... groupRectangles() 함수 쓰려고 했는데안쓰게 되는건가.???

-  MA : 안드로이드에 올려보고 

Reference

[1] Creating Bounding rotated boxes and ellipses for contours

http://docs.opencv.org/doc/tutorials/imgproc/shapedescriptors/bounding_rotated_ellipses/bounding_rotated_ellipses.html

[2] Extract a RotatedRect area

http://answers.opencv.org/question/497/extract-a-rotatedrect-area/

[3] GroupRectangle() Fuction Example

http://tech.groups.yahoo.com/group/OpenCV/message/69397http://tech.groups.yahoo.com/group/OpenCV/message/69397