opencv/samples/swig_python/watershed.py

#!/usr/bin/python
from opencv.cv import *
from opencv.highgui import *
import sys

marker_mask = None;
markers = None;
img0 = None
img = None
img_gray = None 
wshed = None
prev_pt = cvPoint(-1,-1)

def on_mouse( event, x, y, flags, param ):
    global prev_pt
    if( not img ):
        return;
    if( event == CV_EVENT_LBUTTONUP or not (flags & CV_EVENT_FLAG_LBUTTON) ):
        prev_pt = cvPoint(-1,-1);
    elif( event == CV_EVENT_LBUTTONDOWN ):
        prev_pt = cvPoint(x,y);
    elif( event == CV_EVENT_MOUSEMOVE and (flags & CV_EVENT_FLAG_LBUTTON) ):
        pt = cvPoint(x,y);
        if( prev_pt.x < 0 ):
            prev_pt = pt;
        cvLine( marker_mask, prev_pt, pt, cvScalarAll(255), 5, 8, 0 );
        cvLine( img, prev_pt, pt, cvScalarAll(255), 5, 8, 0 );
        prev_pt = pt;
        cvShowImage( "image", img );

if __name__ == "__main__":
    filename = "../c/fruits.jpg"
    if len(sys.argv)>1:
        filename = sys.argv[1]

    rng = cvRNG(-1);
    img0 = cvLoadImage(filename,1)
    if not img0:
        print "Error opening image '%s'" % filename
        sys.exit(-1)

    print "Hot keys:"
    print "\tESC - quit the program"
    print "\tr - restore the original image"
    print "\tw - run watershed algorithm"
    print "\t  (before that, roughly outline several markers on the image)"

    cvNamedWindow( "image", 1 );
    cvNamedWindow( "watershed transform", 1 );

    img = cvCloneImage( img0 );
    img_gray = cvCloneImage( img0 );
    wshed = cvCloneImage( img0 );
    marker_mask = cvCreateImage( cvGetSize(img), 8, 1 );
    markers = cvCreateImage( cvGetSize(img), IPL_DEPTH_32S, 1 );

    cvCvtColor( img, marker_mask, CV_BGR2GRAY );
    cvCvtColor( marker_mask, img_gray, CV_GRAY2BGR );

    cvZero( marker_mask );
    cvZero( wshed );

    cvShowImage( "image", img );
    cvShowImage( "watershed transform", wshed );

    cvSetMouseCallback( "image", on_mouse, None );
    while True:
        c = cvWaitKey(0);
        if c=='\x1b':
            break;
        if c == 'r':
            cvZero( marker_mask );
            cvCopy( img0, img );
            cvShowImage( "image", img );
        if c == 'w':
            storage = cvCreateMemStorage(0);
            comp_count = 0;
            #cvSaveImage( "wshed_mask.png", marker_mask );
            #marker_mask = cvLoadImage( "wshed_mask.png", 0 );
            nb_cont, contours = cvFindContours( marker_mask, storage, sizeof_CvContour,
                            CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE );
            cvZero( markers );
            while contours:
                cvDrawContours( markers, contours, cvScalarAll(comp_count+1),
                                cvScalarAll(comp_count+1), -1, -1, 8, cvPoint(0,0) );
                contours=contours.h_next
                comp_count+=1
            color_tab = cvCreateMat( comp_count, 1, CV_8UC3 );
            for i in range(comp_count):
                color_tab[i] = cvScalar( cvRandInt(rng)%180 + 50, 
                                 cvRandInt(rng)%180 + 50, 
                                 cvRandInt(rng)%180 + 50 );
            t = cvGetTickCount();
            cvWatershed( img0, markers );
            t = cvGetTickCount() - t;
            #print "exec time = %f" % t/(cvGetTickFrequency()*1000.)

            cvSet( wshed, cvScalarAll(255) );

            # paint the watershed image
            for j in range(markers.height):
                for i in range(markers.width):
                    idx = markers[j,i]
                    if idx==-1:
                        continue
                    idx = idx-1
                    wshed[j,i] = color_tab[idx,0]

            cvAddWeighted( wshed, 0.5, img_gray, 0.5, 0, wshed );
            cvShowImage( "watershed transform", wshed );
            cvWaitKey();