2015-05-20 04:36:42 -0600 | received badge | ● Student (source) |
2015-05-19 14:56:43 -0600 | answered a question | BoW in openCV: cluster() takes far too long. How big is your training set? K-Means is an O(n^2) algorithm, so it can take a long time on large datasets. For reference, I trained a similar vocabulary as you with 3138432 SIFT descriptors in it and it took around 48 hours. |
2015-05-19 14:56:43 -0600 | asked a question | BOWKMeansTrainer: vocabulary has incorrect dimensions? I am porting some code over from the Python scikit library to OpenCV and I'm trying to use the BOWKMeansTrainer class to cluster SIFT feature descriptors into a vocabulary. The vocabulary returned does not seem to be the correct dimensions, however. I have added a set of descriptors to my trainer and used the cluster function with K = 50 (gives best performance for my dataset based on my tests using scikit). What is puzzling me is that the vocabulary returned is 50x1. Shouldn't it be 50x128? I am using OpenCV 3.0.0-dev. Here's some code so you can see what I'm doing: |