gistfile1.pyw

#!/usr/bin/python

import sys
import cv
 
def detect(image):
    image_size = cv.GetSize(image)
 
    # create grayscale version
    grayscale = cv.CreateImage(image_size, 8, 1)
    cv.CvtColor(image, grayscale, cv.CV_BGR2GRAY)
 
    # create storage
    storage = cv.CreateMemStorage(0)
 
    # equalize histogram
	#cv.EqualizeHist(grayscale, grayscale)
 
    # detect objects
    cascade = cv.Load('haar/haarcascade_frontalface_alt.xml')	
    #cascade = cv.Load('haar/haarcascade_frontalface_default.xml')
    faces = cv.HaarDetectObjects(grayscale, cascade, storage, 1.2, 2, cv.CV_HAAR_DO_CANNY_PRUNING, (50, 50))
 
    if faces:
        print 'face detected!'
        for i in faces:
	    _x = int(i[0][0])
	    _y = int(i[0][1])
	    _w = int(i[0][2])
	    _h = int(i[0][3])
	    cv.Rectangle(image, (_x, _y), (_x + _w, _y + _h), cv.CV_RGB(0, 255, 0), 3, 8, 0)
 
if __name__ == "__main__":
 
 
    # create windows
    cv.NamedWindow('Camera')
 
    # create capture device
    device = 0 # assume we want first device
    capture = cv.CreateCameraCapture(0)
    cv.SetCaptureProperty(capture, cv.CV_CAP_PROP_FRAME_WIDTH, 640)
    cv.SetCaptureProperty(capture, cv.CV_CAP_PROP_FRAME_HEIGHT, 480)    
 
    # check if capture device is OK
    if not capture:
        print "Error opening capture device"
        sys.exit(1)
 
    while 1:
        # do forever
 
        # capture the current frame
        frame = cv.QueryFrame(capture)
        if frame is None:
            break
 
        # mirror
        cv.Flip(frame, None, 1)
 
        # face detection
        detect(frame)
 
        # display webcam image
        cv.ShowImage('Camera', frame)
 
        # handle events
        k = cv.WaitKey(10)
 
        if k == 0x1b: # ESC
            print 'ESC pressed. Exiting ...'
            break

Esse código foi adaptado desse aqui: http://blog.jozilla.net/2008/06/27/fun-with-python-opencv-and-face-detection/ - que está usando a OpenCV 1.0 com um wrapper pra python. No meu caso, como eu to usando a OpenCV 2.1, que já vem com suporte a Python nativo, precisei fazer umas alterações. =D