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    <p>Your code worked fine for me (although I'm running OpenCV v2.4.3 instead of your version, 2.3.1). I started working from the same online code (posted <a href="http://www.calebmadrigal.com/facial-detection-opencv-python/" rel="nofollow">here</a>) last week, and I eventually gave up on using <code>cv</code> and switched to the new <code>cv2</code> library. </p> <p>So. I've updated your code so that it uses the new <code>cv2</code> interface. </p> <p>The <code>cv2</code> Python interface for running Haar Cascade Classifiers is much easier to use. Check out the documentation for <code>cv2.CascadeClassifier.detectMultiScale()</code> <a href="http://docs.opencv.org/modules/objdetect/doc/cascade_classification.html#cascadeclassifier-detectmultiscale" rel="nofollow">here</a>. The new <code>cv2</code> interface simplifies your code significantly. Here are the highlights:</p> <ol> <li>You no longer have to worry about creating memory buffers.</li> <li>The results that are returned from <code>detectMultiScale</code> come back in a super useful form, eliminating the need for your old code's <code>detect_faces()</code> function!</li> <li>You only need to provide one parameter: the image itself. All other parameters are optional. I've included the parameters you were using in the revised code below, but feel free to remove them.</li> </ol> <p>One piece of advice: if your code is running slowly, one of the best things you can do is increase the minSize. For my webcam, using (100,100) causes a super-slow frame rate of about 0.2fps. Changing it to (300,300) boosts it to the respectable 20fps.</p> <p>The code should work on your existing installation since you're running 2.3.1, but if it doesn't then try upgrading to the latest version.</p> <pre><code>import cv2 import cv2.cv as cv HAAR_CASCADE_PATH = "/home/OpenCV-2.3.1/data/haarcascades/haarcascade_frontalface_default.xml"; CAMERA_INDEX = 0; if __name__ == "__main__": # Open window, load webcam and load Haar cascade classifier cv2.namedWindow("Video", cv.CV_WINDOW_AUTOSIZE) capture = cv2.VideoCapture(CAMERA_INDEX); cascade = cv2.CascadeClassifier(HAAR_CASCADE_PATH); i = 0; while True: # Grab frame from webcam retVal, image = capture.read(); # note: ignore retVal # Only run the Detection algorithm every 5 frames to improve performance #if i%5==0: faces = cascade.detectMultiScale(image, scaleFactor=1.2, minNeighbors=2, minSize=(100,100), flags=cv.CV_HAAR_DO_CANNY_PRUNING); # Draw rectangles on image, and then show it for (x,y,w,h) in faces: cv2.rectangle(image, (x,y), (x+w,y+h), 255) cv2.imshow("Video", image) i += 1; </code></pre>
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    1. POreturn _cv.cvHaarDetectObjects(*args)
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    1. USCommunity
    1. USBrandon Jackson
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    1. POreturn _cv.cvHaarDetectObjects(*args)
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    1. COThanks a lot, It is not working on my system. Error as:Unrecognized or unsupported array type in function cvGetMat. Before installing opencv2.4.3 I want to know, will it work on ubuntu 11.10 system and python 2.7. Because I had faced a lot problem when inatslling opencv2.3.1, so just want to confirm. Thank you.
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      1. USshreya
    2. COHi, I have upgrade it to Opencv-2.4.3. After running your code, it is giving me an error as: Traceback (most recent call last): File "/home/vidula/OpenCV-2.3.1/draft_1.py", line 25, in <module> flags=cv.CV_HAAR_DO_CANNY_PRUNING) error: /home/vidula/OpenCV-2.4.3/modules/core/src/array.cpp:2482: error: (-206) Unrecognized or unsupported array type in function cvGetMat What does this mean?
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    3. COIt means that there is a problem with the array you're passing to imshow(). Try again after reading my answer to your other question.
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