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segmentation fault on traincascade

asked 2015-03-10 09:07:44 -0500

rafafirenze gravatar image

Hello.

I'm getting this weird error. I have 437 positive images and 3019 negative images.

The positive images all taken of 35x35 pixels.

This is the command that I use:

opencv_traincascade -data data -vec lv.vec -bg bg.txt -numPos 437 -numNeg 3019 -numStages 10 -w 35 -h 35

if I use -featureType LBP, it hangs on the 0-stage not calculating anything. If I remove it, this is what happens:

===== TRAINING 0-stage =====
<BEGIN
POS count : consumed   437 : 437
NEG count : acceptanceRatio    3019 : 1
Precalculation time: 3
+----+---------+---------+
|  N |    HR   |    FA   |
+----+---------+---------+
|   1|        1|        1|
+----+---------+---------+
|   2|        1|        1|
+----+---------+---------+
|   3|        1| 0.988738|
+----+---------+---------+
|   4|        1| 0.998344|
+----+---------+---------+
|   5|        1| 0.998675|
+----+---------+---------+
Segmentation fault: 11

When I try to retry the process, I get:

PARAMETERS:
cascadeDirName: data
vecFileName: /Users/rafaelruizmunoz/Desktop/metal/lv.vec
bgFileName: bg.txt
numPos: 437
numNeg: 3019
numStages: 10
precalcValBufSize[Mb] : 256
precalcIdxBufSize[Mb] : 256
stageType: BOOST
featureType: HAAR
sampleWidth: 35
sampleHeight: 35
boostType: GAB
minHitRate: 0.995
maxFalseAlarmRate: 0.5
weightTrimRate: 0.95
maxDepth: 1
maxWeakCount: 100
mode: BASIC

Stage 0 is loaded

===== TRAINING 1-stage =====
<BEGIN
POS OpenCV Error: Bad argument (Can not get new positive sample. The most possible reason is insufficient count of samples in given vec-file.
) in get, file /Users/rafaelruizmunoz/Downloads/opencv/apps/traincascade/imagestorage.cpp, line 163
libc++abi.dylib: terminating with uncaught exception of type cv::Exception: /Users/rafaelruizmunoz/Downloads/opencv/apps/traincascade/imagestorage.cpp:163: error: (-5) Can not get new positive sample. The most possible reason is insufficient count of samples in given vec-file.
 in function get

Abort trap: 6

Does anyone know what is happening?

Thank you in advance.

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Comments

Aren't there too few positives relative to the number of negatives?

thdrksdfthmn gravatar imagethdrksdfthmn ( 2015-03-10 09:10:08 -0500 )edit

Hi @thdrksdfthmn , in my experience I've just used cascades downloaded from Internet... would you reccomend me a ratio of pos/neg ??

rafafirenze gravatar imagerafafirenze ( 2015-03-10 09:18:03 -0500 )edit

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answered 2015-03-10 09:22:03 -0500

fedor gravatar image

updated 2015-03-10 09:23:03 -0500

Hi ! In error already writen the answer - " Can not get new positive sample " How you can read in the docs opencv_traincascade arguments numPos and numNeg is number of positive/negative samples used in training for every classifier stage. So if you have 437 positive samples put as numPos argument 437 / numStages.

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Hello @fedor, thank you for your answer. I reduced the number to 315 and I did the -numPos / numStages, setting -numStages to 10. So the new command would be :

opencv_traincascade -data data -vec "/Users/rafaelruizmunoz/Desktop/metal/lv.vec" -bg bg.txt -numPos 31 -numNeg 3019 -numStages 10 -w 35 -h 35

But I got Segmentation fault again.

rafafirenze gravatar imagerafafirenze ( 2015-03-10 09:58:14 -0500 )edit

I've tried to make a -numNeg lower as well

rafafirenze gravatar imagerafafirenze ( 2015-03-10 10:04:47 -0500 )edit

numNeg must be around 300 . If you will have errors with numNeg = 300 then write full error, like you did before :)

fedor gravatar imagefedor ( 2015-03-10 10:12:41 -0500 )edit

Sorry, doesn't change very much:

===== TRAINING 0-stage =====
<BEGIN
POS count : consumed   43 : 43
NEG count : acceptanceRatio    300 : 1
Precalculation time: 1
+----+---------+---------+
|  N |    HR   |    FA   |
+----+---------+---------+
|   1|        1|        1|
+----+---------+---------+
|   2|        1| 0.833333|
+----+---------+---------+
|   3|        1| 0.726667|
+----+---------+---------+
|   4|        1|     0.78|
+----+---------+---------+
Segmentation fault: 11
rafafirenze gravatar imagerafafirenze ( 2015-03-10 10:20:23 -0500 )edit

hmm, yes, not very informative

maybe, if you "try to retry the process" you will get more informative error

fedor gravatar imagefedor ( 2015-03-10 18:00:00 -0500 )edit
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Asked: 2015-03-10 09:07:44 -0500

Seen: 1,319 times

Last updated: Mar 10 '15