OpenCV Face Detection For Cropping Faces

Re:OpenCV Face Detection For Cropping Faces by geuis on Wednesday June 19, 2013 @05:34PM (#5908465)

I implemented something like this with OpenCV late last year using a node.js wrapper. We were looking to do something similar for image cropping. What I found was that OCV was kind of unreliable. A major percent of the time, it would mark knees as faces or even wrinkles in pictures of women's handbags. It was a side project and we didn't pursue it, so I was unclear if there was a way to train it over time. If so, did you do this to improve your accuracy?

I also used PIL a few years back to do image generation from text. I kept running into memory fragmentation bugs, weird artifacts creeping into images, etc. I haven't been able to recommend PIL for any serious work since then. Has this gotten better?

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Re:OpenCV Face Detection For Cropping Faces by philipcristiano on Wednesday June 19, 2013 @06:06PM (#5908702)

We haven't trained our model at all and just use the include XML file. We have adjusted the default neighbors threshold which helps mitigate the knee factor. Faces tend to be in the 40+ neighbors range from my trials and the default is 3.

We use ImageMagick for cropping and resizing, PIL was just easier for the example. I haven't noticed any issue with PIL but I also haven't used it for any serious image processing.

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