Error "Train dataset for temp stage can not be filled." while using traincascade tool of OpenCV

Question

I'm building the opencv_traincascade.exe tool from source code (OpenCV 2.4.0) using vs2010 on windows 7. I want to train a LBP classifier, so I'm using opencv_traincascade.exe with the following arguments

-data D:\OpenCV\Classifiers\lbpclassifier1\temp\data -vec D:\OpenCV\Classifiers\lbpclassifier1\temp\samples.vec -bg D:\OpenCV\Classifiers\lbpclassifier1\temp\negative\infofile.txt -numPos 40 -numNeg 40 -precalcIdxBufSize 500 -precalcValBufSize 500 -stageType BOOST -featureType LBP -w 24 -h 24

The error message that I get is:

PARAMETERS:
cascadeDirName: D:\OpenCV\Classifiers\lbpclassifier1\temp\data
vecFileName: D:\OpenCV\Classifiers\lbpclassifier1\temp\samples.vec
bgFileName: D:\OpenCV\Classifiers\lbpclassifier1\temp\negative\infofile.txt
numPos: 2
numNeg: 40
numStages: 20
precalcValBufSize[Mb] : 500
precalcIdxBufSize[Mb] : 500
stageType: BOOST
featureType: LBP
sampleWidth: 24
sampleHeight: 24
boostType: GAB
minHitRate: 0.995
maxFalseAlarmRate: 0.5
weightTrimRate: 0.95
maxDepth: 1
maxWeakCount: 100

===== TRAINING 0-stage =====
<BEGIN
POS count : consumed   2 : 2
Train dataset for temp stage can not be filled. Branch training terminated.

This question has been asked before : Error while using opencv_train cascade , and the solution suggested there viz. making the number of positive and negative samples equal doesn't help in this case.

I thought that the error might be related to this bug : http://code.opencv.org/issues/1834 So, I downloaded the latest release of imagestorage.cpp from that page and rebuilt the opencv_traincascades tool. Also, the total number of samples in the .vec file is 45. So as suggested in this comment I have changed the numPos argument to 2, so that I don't run out of samples in the .vec file. The number of samples in the .vec file is 45.

Any help is much appreciated. Thanks.

Answer 1

First, for me too, the error was with the bg file. I use Opencv 2.4.10.1.

I got the error when I specified the absolute path to the bg file in the command (like the author of the post). Looks like the authors did a really, really crappy job on figuring out the full negative image paths. One simple workaround is to simply CD to the dir of the .info file (note -bg infofile.txt)

cd D:\OpenCV\Classifiers\lbpclassifier1\temp\negative
train_cascade -data D:\OpenCV\Classifiers\lbpclassifier1\temp\data -vec D:\OpenCV\Classifiers\lbpclassifier1\temp\samples.vec -bg infofile.txt -numPos 40 -numNeg 40 -precalcIdxBufSize 500 -precalcValBufSize 500 -stageType BOOST -featureType LBP -w 24 -h 24

Answer 2

opencv_traincascade is trying to read the Negative folder images in the current folder. Hence you have to transfer the opencv_traincascade.exe into negative/ images folder.

For example:

- opencv_traincascade.exe -data C:\Users\home\Documents\Face_Detection\HaarTrain\cascades -vec C:\Users\home\Documents\Face_Detection\HaarTrain\vector\vector.vec -bg bg.txt -numPos 130 -numNeg 500 -numStages 10 -precalcValBufSize 1024 -precalcIdxBufSize 1024

Answer 3

I am also learning how to use OpenCV object detection tools.

I noticed that if the bg file (in your case "D:\OpenCV\Classifiers\lbpclassifier1\temp\negative\infofile.txt") has a wrong format or contains a entry with non-existent file, opencv_traincascade produces error.

Hope it helps.