python中使用OpenCV进行人脸检测的例子

# face_detect.py

# Face Detection using OpenCV. Based on sample code from:
# http://python.pastebin.com/m76db1d6b

# Usage: python face_detect.py <image_file>

import sys,os
from opencv.cv import *
from opencv.highgui import *
from PIL import Image,ImageDraw
from math import sqrt

def detectObjects(image):
    """Converts an image to grayscale and prints the locations of any faces found"""
    grayscale = cvCreateImage(cvSize(image.width,image.height),8,1)
    cvCvtColor(image,grayscale,CV_BGR2GRAY)

    storage = cvCreateMemStorage(0)
    cvClearMemStorage(storage)
    cvEqualizeHist(grayscale,grayscale)

    cascade = cvLoadHaarClassifierCascade(
        '/usr/share/opencv/haarcascades/haarcascade_frontalface_default.xml',
        cvSize(1,1))
    faces = cvHaarDetectObjects(grayscale,cascade,storage,1.1,2,
        CV_HAAR_DO_CANNY_PRUNING,cvSize(20,20))

    result = []
    for f in faces:
        result.append((f.x,f.y,f.x+f.width,f.y+f.height))

    return result

def grayscale(r,g,b):
    return int(r * .3 + g * .59 + b * .11)

def process(infile,outfile):

    image = cvLoadImage(infile);
    if image:
        faces = detectObjects(image)

    im = Image.open(infile)

    if faces:
        draw = ImageDraw.Draw(im)
        for f in faces:
            draw.rectangle(f,outline=(255,255))

        im.save(outfile,"JPEG",quality=100)
    else:
        print "Error: cannot detect faces on %s" % infile

if __name__ == "__main__":
    process('input.jpg','output.jpg')