Vlad's profile - activity

Solved.

The problem was in a different matrix, that i've passed from c++ code. When returning a matrix address from jni, i had to use:

Mat ret = getSomeMatrix();
return (jlong) new Mat(ret);

because the java constructor Mat(long addr) doesn't add a reference to the counter of the matrix, but the finalizer does remove one reference.

I want to avoid garbage collection while the app is running. to do so i avoid object allocation as much as possible. BUT, I've already tried putting mFaceList as a local var and the same problem occurred as well.

Hey guys, I'm using OpenCV4Android v.2.4.9 on Nexus 5 with android 4.4.4 stock rom.

I use this piece of code for running haar cascade face detection:

public Rect getFaceFromCascade(){
    // cascade! woohoo
    if (mFrontCascade != null) {
        int height = mWorkingFrame.rows();
        int faceSize = Math.round(height * mMinFaceSize);

        mFrontCascade.detectMultiScale(mWorkingFrame, mFaceList, 
                        1.1, 2, 2 , new Size(faceSize, faceSize), new Size());
    }

    Rect[] facesArray = mFaceList.toArray();

    if (facesArray.length == 0){
        //cascade couldn't find any face
        return null;
    }

    return facesArray[0];
}

mFaceList is a MatOfRect i'm creating once when the class is initialized.

When the class dies, I don't do anything with mFaceList (although i've also tried releasing it and that didn't help), and leave it to the garbage collector, but when the GC comes along later on, i get a SIGSEGV. After deep investigation i found the the problem is when release is called in the MatOfRect (Mat) finalizer.

When my class dies the mFaceList has the following header:

Mat [ 1*1*CV_32SC4, isCont=true, isSubmat=false, nativeObj=0x713cdad8, dataAddr=0x751badf0 ]

and in the finalize method of mFaceList it has the following header:

Mat [ 1964813884*1*CV_32SC(455), isCont=false, isSubmat=true, nativeObj=0x751ad8bc, dataAddr=0x751cae60 ]

That's when the SIGSEGV is occurring. any idea what can mess with the header like that? or why is this happening? I don't have any other references of this MatOfRect anywhere in the code.

Any help would be appreciated. Vlad

I ended up writing a little wrapper for native Kalman filter.. so i'll have to whole functionality. it took about 10 minutes so i guess for now, that's the way to go.

you can use the DDMS tool that comes with the sdk http://developer.android.com/tools/debugging/debugging-tracing.html

Did you find a solution for this? the wrapper makes no sense. I've tried running it without the transition matrix, and the filter does nothing to my values..

Hey guys, i've migrated my project to a new computer, and it stopped working. I get NoClassDefFoundError: org.opencv.objdetect.CascadeClassifier when trying to run it.

I'm using eclipse indigo, on win7, trying to run on andorid 2.3.3. everything worked well before!

i have the opencv2.4.2.jar referenced in my project, (no _src dirs) and i can see the CascadeClassifier.class there.. i don't know what's wrong..

any ideas?