My version that works, I’m not a Python dev so I’m sure there are optimisations etc:

import sys, os
import cv2.cv as cv

image = cv.LoadImage(sys.argv[1])

grayscale = cv.CreateImage((image.width, image.height), 8, 1)
cv.CvtColor(image, grayscale, cv.CV_BGR2GRAY)

storage = cv.CreateMemStorage(0)
cv.EqualizeHist(grayscale, grayscale)
cascade = cv.Load(”)
faces = cv.HaarDetectObjects(grayscale, cascade, storage, 1.2, 2, cv.CV_HAAR_DO_CANNY_PRUNING, (50,50))

if faces:
for f in faces:
print(f)

Note I’m not sure where the ClearMemStorage function has gone and whether del does the same thing or not, someone better at Python might be able to help.

Also the data structures returned are slightly different, each ‘face’ is a tuple containing a rect and an int.

Hope that helps someone.

2. extract
# cd /usr/share/doc/opencv-doc/examples/haarcascades/haarcascades/
# cp *.gz ..
# gunzip *.gz

3. Run (this changes your images and renames the old ones)

#!/usr/bin/python

# 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 *

CLASSIFIER=’/usr/share/doc/opencv-doc/examples/haarcascades/haarcascade_frontalface_default.xml’

def detectObjects(fn, 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(CLASSIFIER, cvSize(1,1))
faces = cvHaarDetectObjects(grayscale, cascade, storage, 1.2, 2,
CV_HAAR_DO_CANNY_PRUNING, cvSize(50,50))

if faces:
for f in faces:
newfn = fn + “.output.jpg”
os.system(“convert %s -stroke red -fill none -draw ‘rectangle %d,%d %d,%d’ %s” % (fn, f.x, f.y, f.x+f.width, f.y+f.height, newfn))
os.system(“mv %s %s.orig” % (fn, fn))
os.system(“mv %s %s” % (newfn, fn))

def main():
image = cvLoadImage(sys.argv[1]);
detectObjects(sys.argv[1], image)

if __name__ == “__main__”:
main()

It’s python, of course, and uses opencv too.

https://github.com/omab/faces

In my ubuntu 11.04, the file is in
/usr/share/doc/opencv-doc/examples/haarcascades/haarcascades/haarcascade_frontalface_default.xml.gz
I just copied it to my working directory and extracted it there.
The code worked after that.

I’m using Ubuntu 10.10 with everything installed from repository. Still get the same error, even with ryanhaigh’s change. The script never gets to that line, so that doesn’t surprise me.

Cheers!

#!/usr/bin/python

# 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 *
import Image, ImageDraw

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/doc/opencv-doc/examples/haarcascades/haarcascades/haarcascade_frontalface_alt.xml’,cvSize(1,1))
faces = cvHaarDetectObjects(grayscale, cascade, storage, 1.2, 2,CV_HAAR_DO_CANNY_PRUNING, cvSize(50,50))

if faces.total > 0:
for f in faces:
x1,y1,x2,y2=f.x,f.y,f.x+f.width,f.y+f.height
print(“[(%d,%d) -> (%d,%d)]” % (x1,y1,x2,y2))
print_rectangle(x1,y1,x2,y2) #call to a python pil

def print_rectangle(x1,y1,x2,y2): #function to modify the img
im = Image.open(sys.argv[1])
draw = ImageDraw.Draw(im)
draw.rectangle([x1,y1,x2,y2])
im.save(sys.argv[1])

def main():
image = cvLoadImage(sys.argv[1]);
detectObjects(image)

if __name__ == “__main__”:
main()

https://bugs.launchpad.net/opencv/+bug/698016