Trouble using Open Image Denoise
As far as I remember, you need to input data in float array. Right now your input is unsigned char array. To quick check this, try loading any HDR image in float array &amp; pass it on to the setImage functions, this seems to work. 

In your case, you would need to read individual image channel data &amp; cast it to float. If your image color is stored in [0-255] range, you would then need to bring it to [0-1] range (Not completely sure about this stage!) &amp; then pass the data in float array to denoiser functions.

Hope this helps.