Haar Classifier

Athena on November 23rd, 2011

When creating samples from the marked images the default options are listed below. You notice that the default for the maxzangle is less than the defaults for the x and y angle values. So why is that? What do these parameters mean?   The Haar Classifier was initially developed for facial detections, but has been […]

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Athena on September 10th, 2011

In running through tests against all the haarcascades I create, I noticed that the number of Misses in Quadrant III seemed surprisingly high, even when the cavity was a very distinct one.   Here is an example of the original image that was used to train the cascades. Here is an output file from the […]

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Athena on August 14th, 2011

Once you have a *.xml file that you created from training the classifier then you can test the performance of that classifier cascade against your prositive test or you could create a validation test set to test performance against. OpenCV comes with a built in performance utility C:\OpenCV2.2\bin>opencv_performance.exe -data “C:\My Documents\HaarClassifier\haarcascade\haarcascade.xml” -info “C:\My Documents\Positive Test […]

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Athena on August 13th, 2011

Once your training is done there will be a number of directories created in your haarcascade location you specified when your training first began. The directories will be labelled from 0…N where N is the total number of stages the trainer completed. In each directory there will be one AdaBoostCARTHaarClassisifer.txt file and each of the […]

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Athena on August 13th, 2011

When going through the training stages you might find that your training has come to a halt where its progress isn’t getting any further and or it has exited out improperly. If this happens you can still turn the stages it did successfully complete into a Classifier Cascade XML. OpenCV comes with a built in […]

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Athena on August 13th, 2011

Once you have a *.vec file that you created from your positive images you are ready to train your classifier. OpenCV comes with a built in training utility opencv_haartraining.exe -data “C:\My Documents\HaarClassifier\haarcascade” -vec “C:\My Documents\Positive Test Set\positives.vec” -bg “C:\My Documents\Negative Test Set\negatives.txt” -npos 1134 -nneg 625 -nstages 20 Explanation of the code above: opencv_haartraining.exe is […]

Continue reading about Training a Haar Classifier

Athena on August 12th, 2011

Once you have a file that lists your positive images with the corresponding positive locations within each image you can then create a training sample based off of this file that will then create a vector of samples and translations to be used to train your classifier. opencv_createsamples.exe -info “C:\My Documents\Positive Test Set\positives.txt” -vec “C:\My […]

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Athena on August 10th, 2011

How do we tell our program what we want to look for? I created a directory full of positive images (images that contain the object(s) that I want to identify) and I created a directory full of images that I know do not contain any of the objects that I want to identify. My positive […]

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Athena on August 8th, 2011

Machine Learning is a rapidly growing Haar Classifier is a supervised classifier, it has mainly been used for facial detection but it can also be trained to detect other objects. Computer vision is such a growing field that there are so many resources available for your own personal use. OpenCV provides a lot of functionality […]

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