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python中使用OpenCV进行人脸检测的例子

发布时间：2024-04-23 19:20:32 来源：好代码

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泰山日出天色略显昏暗，放眼望去，寂寥晨星下面是一片静止的山势般起伏的云海，在茫茫的夜色下，象极了远处同样黑魆魆的山峰。

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 <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, 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')