RetinaFastToneMapping Class Returning Zero Mat in Java Wrapper

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Hello! I am trying to use the RetinaFastToneMapping class in the opencv contrib module in java, but keep running into a strange problem. The function that does the tone mapping doesn't seem to be able to actually return the luminence-corrected image. Instead, it creates a blank image of the same size and type as the input (when I say blank, I mean filled with zeros). This is the code I am using to test the class:

    Mat input = Imgcodecs.imread(filepath,Imgcodecs.IMREAD_GRAYSCALE);

    RetinaFastToneMapping retina = RetinaFastToneMapping.create(input.size());

    retina.setup();

    input.convertTo(input,CvType.CV_64F);
    Mat test = new Mat(input.size(),input.type());
    retina.applyFastToneMapping(input,test);`:

I am using opencv 4.0.1 to test, so it is possible that this issue has since been fixed, but I can't find any references to it anywhere, so it seemed reasonable to ask on here. If I am using the RetinaFastToneMapping class wrong, then that could be the problem as well. I would appreciate any help anyone can give me on this problem as i've been stuck on it for quite some time. I've been running the code on this image: Thank you for taking the time to read this question!