OpenCV random image loading error

Question

I am using emgu opencv version 2.4.2 to process a series of PNG images extracted from a 720p video. I use this code to read the image:

image = new Image<Bgr, byte>(filename);

At a random image in my PNG sequence I get:

Convertion from Image<Emgu.CV.Structure.Bgra, System.Byte> to
Image<Emgu.CV.Structure.Bgr, System.Byte> is not supported by OpenCV

Indicating the input image has an alpha channel, and cannot be read directly to a 24 bit image structure.

But, the exception never occurs on the same image. So, the next time I run the program it will probably be read just fine. The exception usually occur quite far into the PNG sequence, like frame 300. Other times it runs fine to a later frame. But it would be normally stop around frame 300-320.

I am not doing any kind of threading here that could potentially cause seemingly random issues, it is a very basic program reading one image, doing some basic modifications to it, then saving it to another file.

I guess a workaround is to simply catch the exception and try again, but that seems messy.

is there anything I am missing here?

Answer 1

Turns out the problem was the garbage collector will not automatically clean up OpenCV Image objects, you need to do it manually by an image.Dispose(). Probably because it is linked to a Bitmap object, which wont be cleaned up automatically due to its native implementation.

The exception I got was misleading, and the issue was caused by memory leakage which eventually prevented the next image in the sequence from loading successfully.