opencv/samples/octave/contours.m

141 lines
3.9 KiB
Matlab

#! /usr/bin/env octave
printf("OpenCV Octave version of contours\n");
## import the necessary things for OpenCV
cv;
global _SIZE;
global _red;
global _green;
global _blue;
global contours;
## some default constants
_SIZE = 500;
_DEFAULT_LEVEL = 3;
## definition of some colors
_red = cvScalar (0, 0, 255, 0);
_green = cvScalar (0, 255, 0, 0);
_white = cvRealScalar (255);
_black = cvRealScalar (0);
## the callback on the trackbar, to set the level of contours we want
## to display
function on_trackbar (position)
global cv;
global _SIZE;
global _red;
global _green;
global _blue;
global contours;
## create the image for putting in it the founded contours
contours_image = cvCreateImage (cvSize (_SIZE, _SIZE), 8, 3);
## compute the real level of display, given the current position
levels = position - 3;
## initialisation
_contours = contours;
if (levels <= 0)
## zero or negative value
## => get to the nearest face to make it look more funny
_contours = contours.h_next.h_next.h_next;
endif
## first, clear the image where we will draw contours
cvSetZero (contours_image);
## draw contours in red and green
cvDrawContours (contours_image, _contours, _red, _green, levels, 3, cv.CV_AA, cvPoint (0, 0));
## finally, show the image
cvShowImage ("contours", contours_image);
endfunction
## create the image where we want to display results
image = cvCreateImage (cvSize (_SIZE, _SIZE), 8, 1);
## start with an empty image
cvSetZero (image);
## draw the original picture
for i=0:6-1,
dx = mod(i,2) * 250 - 30;
dy = (i / 2) * 150;
cvEllipse (image,
cvPoint (dx + 150, dy + 100),
cvSize (100, 70),
0, 0, 360, _white, -1, 8, 0);
cvEllipse (image,
cvPoint (dx + 115, dy + 70),
cvSize (30, 20),
0, 0, 360, _black, -1, 8, 0);
cvEllipse (image,
cvPoint (dx + 185, dy + 70),
cvSize (30, 20),
0, 0, 360, _black, -1, 8, 0);
cvEllipse (image,
cvPoint (dx + 115, dy + 70),
cvSize (15, 15),
0, 0, 360, _white, -1, 8, 0);
cvEllipse (image,
cvPoint (dx + 185, dy + 70),
cvSize (15, 15),
0, 0, 360, _white, -1, 8, 0);
cvEllipse (image,
cvPoint (dx + 115, dy + 70),
cvSize (5, 5),
0, 0, 360, _black, -1, 8, 0);
cvEllipse (image,
cvPoint (dx + 185, dy + 70),
cvSize (5, 5),
0, 0, 360, _black, -1, 8, 0);
cvEllipse (image,
cvPoint (dx + 150, dy + 100),
cvSize (10, 5),
0, 0, 360, _black, -1, 8, 0);
cvEllipse (image,
cvPoint (dx + 150, dy + 150),
cvSize (40, 10),
0, 0, 360, _black, -1, 8, 0);
cvEllipse (image,
cvPoint (dx + 27, dy + 100),
cvSize (20, 35),
0, 0, 360, _white, -1, 8, 0);
cvEllipse (image,
cvPoint (dx + 273, dy + 100),
cvSize (20, 35),
0, 0, 360, _white, -1, 8, 0);
endfor
## create window and display the original picture in it
cvNamedWindow ("image", 1);
cvShowImage ("image", image);
## create the storage area
storage = cvCreateMemStorage (0);
## find the contours
[nb_contours, contours] = cvFindContours (image, storage, sizeof_CvContour, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, cvPoint (0,0));
## comment this out if you do not want approximation
contours = cvApproxPoly (contours, sizeof_CvContour, storage, CV_POLY_APPROX_DP, 3, 1);
## create the window for the contours
cvNamedWindow ("contours", 1);
## create the trackbar, to enable the change of the displayed level
cvCreateTrackbar ("levels+3", "contours", 3, 7, @on_trackbar);
## call one time the callback, so we will have the 1st display done
on_trackbar (_DEFAULT_LEVEL);
## wait a key pressed to end
cvWaitKey (0);