Three bugs found in GLCM about texture analysis

老外发现的opencv中cvtexture中的三个bug
出处：http://tech.groups.yahoo.com/group/OpenCV/messages/18038?threaded=1&m=e&var=1&tidx=1

Hello everybody,
I ever delivered two articles about GLCM, asking about how to use it(exactly the meaning of the structure member and the meaning of

the function parameters, see 17848).It seems few people are dealing with it and so no one answered me. It is said that you can count on

yourself if no one can be relied on. So I read the whole source code. Fortunately, I have comprehended 90% of them and found 3 bugs

which are listed below. Anyone who is dealing with texture analysis is welcome to get contact with me. We can communicate with each

other. And two heads are always better than one head. Best wishes to everyone~!

In the file “cvtexture.cpp”

(1).In the function “cvCreateGLCM()”,when we allocate memory to the pointer of structure GLCM, “newGLCM”. A mistake was made here.

The original code is:

  CV_CALL(newGLCM=(CvGLCM*)cvAlloc(sizeof(newGLCM)));
memset( newGLCM, 0, sizeof(newGLCM) );

The right one is:
CV_CALL( newGLCM = (CvGLCM*)cvAlloc(sizeof(CvGLCM)));
memset( newGLCM, 0, sizeof(CvGLCM) );

(2).In the function “icvCreateGLCM_LookupTable_8u_C1R()”,when we allocate memory to one member of structure GLCM, double ***matrices.

Here appears another mistake. They should be replaced by the commentary.

   CV_CALL(matrices[stepLoop]=(double**)cvAlloc( sizeof(matrices[0])*matrixSideLength ));//BUG!

//CV_CALL(matrices[stepLoop]=(double**)cvAlloc( sizeof(matrices[0][0])*matrixSideLength ));

CV_CALL(matrices[stepLoop][0]=(double*)cvAlloc (sizeof(matrices[0][0])matrixSideLength*matrixSideLength ));//BUG!
//CV_CALL(matrices[stepLoop][0]=(double*)cvAlloc ( sizeof(double)*matrixSideLength*matrixSideLength ));

memset(matrices[stepLoop]0],0,matrixSideLength*matrixSideLength*sizeof(matrices[0][0]) );//BUG
//memset(matrices[stepLoop][0],0,atrixSideLength*matrixSideLength*sizeof(double));

(3)In the function “icvCreateGLCMDescriptors_AllowDoubleNest()”,the last statement “delete [] marginalProbability;

”should be replaced by “cvFree( (void**)&marginalProbability);” Because the forward statement

“double*marginalProbability=(double*)cvAlloc(matrixSideLength*sizeof(marginalProbability[0]));”.

Allocation of memory should be coincided with the release of memory.“malloc” with “free”,and “new” with“delete”.

That’s all. Thank you for your attention~!

我按照上面所说的修改完三个bug所确实可以运行，但有个严重的问题，那就是内存泄漏，检测一个几分钟的视频内存都被吸光了，机子动不了，只能关机重启。

经过断点排查，原来cvReleaseGLCM函数中还有一个bug，就是
if(*GLCM)
EXIT; // repeated deallocation: just skip it.
 

应该改为

if(!(*GLCM))
EXIT; // repeated deallocation: just skip it.

[/code]
近期使用二值化图像进行提取纹理特征，发现会报错，原来函数icvCreateGLCMDescriptors_AllowDoubleNest有漏洞，修改如下：[/code]

原始代码：

marginalProbabilityEntropy += marginalProbability[ actualSideLoop1 ]*log(marginalProbability[ actualSideLoop1 ]);
double HXYValue = marginalProbability[ actualSideLoop1 ] * marginalProbability[ actualSideLoop2 ];

[/code]

应该修改为：

marginalProbabilityEntropy += marginalProbability[ sideLoop1 ]*log(marginalProbability[ sideLoop1 ]);
double HXYValue = marginalProbability[ sideLoop1 ] * marginalProbability[ sideLoop2 ];

[/code]
[/code]

这样，opencv的纹理检测就完善了。