OpenCV to find the bird in Angry Birds

terminator-vision.py

#!/opt/local/bin/python2.7

import cv
import subprocess
import time

# Template to find
template_file = cv.CaptureFromFile('redbird.png')
template = cv.QueryFrame(template_file)

window_name = "Skynet"
threshold   = 5510000.0

cv.NamedWindow(window_name, cv.CV_WINDOW_AUTOSIZE)

while True:
    # Get frame
    result = subprocess.call(['./v2u', 'frame.bmp']
                             , stdout=subprocess.PIPE
                             , stderr=subprocess.PIPE)

    # Convert frame to opencv format
    frame_file = cv.CaptureFromFile('frame.bmp')
    frame = cv.QueryFrame(frame_file)
    cv.ShowImage(window_name, frame)

    # Find bird
    W,H=cv.GetSize(frame)
    w,h=cv.GetSize(template)
    width=W-w+1
    height=H-h+1
    result=cv.CreateImage((width,height),32,1)
    cv.MatchTemplate(frame, template, result,cv.CV_TM_SQDIFF)
    (minval,maxval,minloc,maxloc)=cv.MinMaxLoc(result,mask=None)
    (x,y)=minloc
    if minval < threshold:
    #if 1:
        print ("%s < %s :-)" % (minval, threshold))
        cv.Rectangle(frame,
                     ( int(x), int(y) ),
                     ( int(x)+w,int(y)+h ),
                     (255,255,255),
                     3,
                     0)
    else:
        print ("%s > %s" % (minval, threshold))

    # Show image
    cv.ShowImage(window_name, frame)
    if cv.WaitKey(10) == 27:
        break