Postprocessing

I implement three postprocessors in addition to denoising:

• Crop: Crop the image by specifying up to four values (using a system adopted from the CSS margin property).
• Bars: Add (colored) bars of specified width around the image.
• BrightnessContrast: adjust the brightness and / or the contrast of the image. This postprocessor was also used for my final submission (see images below).

The implementation of the brightness-contrast effect follows the implementation of the respective compositing node in Blender, which in turn is based on an implementation from OpenCV. OpenCV mentions Werner D. Streidt as the creator of the algorithm. The link to a mailing list archive they provide is dead, but I managed to access it using the Wayback Machine

The left image shows the raw render. On the right, a subtle contrast enhancement has been applied.