+++ /dev/null
-//
-// The full "Square Detector" program.
-// It loads several images subsequentally and tries to find squares in
-// each image
-//
-#include "opencv2/imgproc/imgproc_c.h"
-#include "opencv2/highgui/highgui.hpp"
-#include <stdio.h>
-#include <math.h>
-#include <string.h>
-
-int thresh = 50;
-IplImage* img = 0;
-IplImage* img0 = 0;
-CvMemStorage* storage = 0;
-const char* wndname = "Square Detection Demo";
-
-// helper function:
-// finds a cosine of angle between vectors
-// from pt0->pt1 and from pt0->pt2
-double angle( CvPoint* pt1, CvPoint* pt2, CvPoint* 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);
-}
-
-// returns sequence of squares detected on the image.
-// the sequence is stored in the specified memory storage
-CvSeq* findSquares4( IplImage* img, CvMemStorage* storage )
-{
- CvSeq* contours;
- int i, c, l, N = 11;
- CvSize sz = cvSize( img->width & -2, img->height & -2 );
- IplImage* timg = cvCloneImage( img ); // make a copy of input image
- IplImage* gray = cvCreateImage( sz, 8, 1 );
- IplImage* pyr = cvCreateImage( cvSize(sz.width/2, sz.height/2), 8, 3 );
- IplImage* tgray;
- CvSeq* result;
- double s, t;
- // create empty sequence that will contain points -
- // 4 points per square (the square's vertices)
- CvSeq* squares = cvCreateSeq( 0, sizeof(CvSeq), sizeof(CvPoint), storage );
- // select the maximum ROI in the image
- // with the width and height divisible by 2
- cvSetImageROI( timg, cvRect( 0, 0, sz.width, sz.height ));
-
- // down-scale and upscale the image to filter out the noise
- cvPyrDown( timg, pyr, 7 );
- cvPyrUp( pyr, timg, 7 );
- tgray = cvCreateImage( sz, 8, 1 );
-
- // find squares in every color plane of the image
- for( c = 0; c < 3; c++ )
- {
- // extract the c-th color plane
- cvSetImageCOI( timg, c+1 );
- cvCopy( timg, tgray, 0 );
-
- // try several threshold levels
- for( l = 0; l < N; l++ )
- {
- // hack: use Canny instead of zero threshold level.
- // Canny helps to catch squares with gradient shading
- if( l == 0 )
- {
- // apply Canny. Take the upper threshold from slider
- // and set the lower to 0 (which forces edges merging)
- cvCanny( tgray, gray, 0, thresh, 5 );
- // dilate canny output to remove potential
- // holes between edge segments
- cvDilate( gray, gray, 0, 1 );
- }
- else
- {
- // apply threshold if l!=0:
- // tgray(x,y) = gray(x,y) < (l+1)*255/N ? 255 : 0
- cvThreshold( tgray, gray, (l+1)*255/N, 255, CV_THRESH_BINARY );
- }
-
- // find contours and store them all as a list
- cvFindContours( gray, storage, &contours, sizeof(CvContour),
- CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE, cvPoint(0,0) );
-
- // test each contour
- while( contours )
- {
- // approximate contour with accuracy proportional
- // to the contour perimeter
- result = cvApproxPoly( contours, sizeof(CvContour), storage,
- CV_POLY_APPROX_DP, cvContourPerimeter(contours)*0.02, 0 );
- // square contours should have 4 vertices after approximation
- // relatively large area (to filter out noisy contours)
- // and be convex.
- // Note: absolute value of an area is used because
- // area may be positive or negative - in accordance with the
- // contour orientation
- if( result->total == 4 &&
- cvContourArea(result,CV_WHOLE_SEQ,0) > 1000 &&
- cvCheckContourConvexity(result) )
- {
- s = 0;
-
- for( i = 0; i < 5; i++ )
- {
- // find minimum angle between joint
- // edges (maximum of cosine)
- if( i >= 2 )
- {
- t = fabs(angle(
- (CvPoint*)cvGetSeqElem( result, i ),
- (CvPoint*)cvGetSeqElem( result, i-2 ),
- (CvPoint*)cvGetSeqElem( result, i-1 )));
- s = s > t ? s : t;
- }
- }
-
- // if cosines of all angles are small
- // (all angles are ~90 degree) then write quandrange
- // vertices to resultant sequence
- if( s < 0.3 )
- for( i = 0; i < 4; i++ )
- cvSeqPush( squares,
- (CvPoint*)cvGetSeqElem( result, i ));
- }
-
- // take the next contour
- contours = contours->h_next;
- }
- }
- }
-
- // release all the temporary images
- cvReleaseImage( &gray );
- cvReleaseImage( &pyr );
- cvReleaseImage( &tgray );
- cvReleaseImage( &timg );
-
- return squares;
-}
-
-
-// the function draws all the squares in the image
-void drawSquares( IplImage* img, CvSeq* squares )
-{
- CvSeqReader reader;
- IplImage* cpy = cvCloneImage( img );
- int i;
-
- // initialize reader of the sequence
- cvStartReadSeq( squares, &reader, 0 );
-
- // read 4 sequence elements at a time (all vertices of a square)
- for( i = 0; i < squares->total; i += 4 )
- {
- CvPoint pt[4], *rect = pt;
- int count = 4;
-
- // read 4 vertices
- CV_READ_SEQ_ELEM( pt[0], reader );
- CV_READ_SEQ_ELEM( pt[1], reader );
- CV_READ_SEQ_ELEM( pt[2], reader );
- CV_READ_SEQ_ELEM( pt[3], reader );
-
- // draw the square as a closed polyline
- cvPolyLine( cpy, &rect, &count, 1, 1, CV_RGB(0,255,0), 3, CV_AA, 0 );
- }
-
- // show the resultant image
- cvShowImage( wndname, cpy );
- cvReleaseImage( &cpy );
-}
-
-
-char* names[] = { "pic1.png", "pic2.png", "pic3.png",
- "pic4.png", "pic5.png", "pic6.png", 0 };
-
-int main(int argc, char** argv)
-{
- int i, c;
- // create memory storage that will contain all the dynamic data
- storage = cvCreateMemStorage(0);
-
- for( i = 0; names[i] != 0; i++ )
- {
- // load i-th image
- img0 = cvLoadImage( names[i], 1 );
- if( !img0 )
- {
- printf("Couldn't load %s\n", names[i] );
- continue;
- }
- img = cvCloneImage( img0 );
-
- // create window and a trackbar (slider) with parent "image" and set callback
- // (the slider regulates upper threshold, passed to Canny edge detector)
- cvNamedWindow( wndname, 1 );
-
- // find and draw the squares
- drawSquares( img, findSquares4( img, storage ) );
-
- // wait for key.
- // Also the function cvWaitKey takes care of event processing
- c = cvWaitKey(0);
- // release both images
- cvReleaseImage( &img );
- cvReleaseImage( &img0 );
- // clear memory storage - reset free space position
- cvClearMemStorage( storage );
- if( (char)c == 27 )
- break;
- }
-
- cvDestroyWindow( wndname );
-
- cvReleaseMemStorage(&storage);
-
- return 0;
-}
projects / profile / ivi / opencv.git / commitdiff
