python+OpenCV进行人脸检测【转】

OpenCV的人脸检测功能在一般场合还是不错的。而ubuntu正好提供了python-opencv这个包，用它可以方便地实现人脸检测的代码。

写代码之前应该先安装python-opencv：

$ sudo apt-get install python-opencv

具体原理就不多说了，可以参考一下这篇文章。直接上源代码。

#!/usr/bin/python

# -*- coding: UTF-8 -*-

# face_detect.py

# Face Detection using OpenCV. Based on sample code from:

# http://python.pastebin.com/m76db1d6b

# Usage: python face_detect.py

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, 0, 255))

        im.save(outfile, "JPEG", quality=100)

    else:

        print "Error: cannot detect faces on %s" % infile

if __name__ == "__main__":

    process(\'input.jpg\', \'output.jpg\')