Open CV memory stacked (not released properly) - objective-c

Question

I am using 3rd party library for image processing, this method seems to be the cause of large memory usage (+30MB) everytime it executed, and it won't release properly. Repeated use of it ends up crashing the app (memory overload). The image used is directly from camera of my iP6.
+ (UIImage *)UIImageFromCVMat:(cv::Mat)cvMat
{
NSData *data = [NSData dataWithBytes:cvMat.data length:cvMat.elemSize() * cvMat.total()];
CGColorSpaceRef colorSpace;
if (cvMat.elemSize() == 1) {
colorSpace = CGColorSpaceCreateDeviceGray();
} else {
colorSpace = CGColorSpaceCreateDeviceRGB();
}
CGDataProviderRef provider = CGDataProviderCreateWithCFData((__bridge CFDataRef)data);
CGImageRef imageRef = CGImageCreate(cvMat.cols, // Width
cvMat.rows, // Height
8, // Bits per component
8 * cvMat.elemSize(), // Bits per pixel
cvMat.step[0], // Bytes per row
colorSpace, // Colorspace
kCGImageAlphaNone | kCGBitmapByteOrderDefault, // Bitmap info flags
provider, // CGDataProviderRef
NULL, // Decode
false, // Should interpolate
kCGRenderingIntentDefault); // Intent
// UIImage *image = [[UIImage alloc] initWithCGImage:imageRef];
UIImage *image = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
CGDataProviderRelease(provider);
CGColorSpaceRelease(colorSpace);
return image;
}
I suspect the problem is here: (__bridge CFDataRef)data. I cant use CFRelease on it cause it make app crash. Project is running with ARC.
EDIT:
It seems the same code is also in openCV official website:
http://docs.opencv.org/2.4/doc/tutorials/ios/image_manipulation/image_manipulation.html
Gah!
EDIT 2
Here is the code how I use it (actually below code is also a part of the 3rd party lib, but i added some lines).
cv::Mat undistorted = cv::Mat( cvSize(maxWidth,maxHeight), CV_8UC4); // here nothing
cv::Mat original = [MMOpenCVHelper cvMatFromUIImage:_adjustedImage]; // here +30MB
//NSLog(#"%f %f %f %f",ptBottomLeft.x,ptBottomRight.x,ptTopRight.x,ptTopLeft.x);
cv::warpPerspective(original, undistorted,
cv::getPerspectiveTransform(src, dst), cvSize(maxWidth, maxHeight)); // here +16MB
_cropRect.hidden=YES;
#autoreleasepool {
_sourceImageView.image=[MMOpenCVHelper UIImageFromCVMat:undistorted]; // here +15MB (PROBLEM)
}
original.release(); // here -30MB (THIS IS OK)
undistorted.release(); // here -16MB (ok)

Answer 1

Guess it is a hard subject since not many people knows OpenCV that well. What I found is that most answer for the similar problem involves putting #autoreleasepool where this method is used. But seems to be not releasing memory either.
As temporary solution I resize the image fed to this method by half. At least app will last longer before it crash finally. It just works.