Monthly Archives: March 2013

kill sharpness softly – bayer filtering in nuke

Finally, it’s time to start posting stuff on my blog. I plan to share relevant knowledge about rendering and compositing here. I will also upload nuke gizmos and all kinds of scripts I created which have proven to be useful in production.

Being confronted with combining CG elements and digitally recorded footage I figured that it would be helpful to apply the processing of a digital cameras sensor to those elements. Many digital cameras (like the Arri Alexa) use single-bayer sensors that are composed of 2×2 arrays of photosites, each site being sensitive to either red, green and blue wavelengths. Since the human eye is mainly sensitive to the green spectrum there are twice as many photosites to record this spectrum than for red and blue wavelenghts in order to achieve a denser sampling for this important (because of its high contribution to luminance perception) channel. In order to convert the raw output from the sensor to a visually pleasing image the pattern needs to be de-bayered by filling the gaps in each color channel caused by the bayer pattern via interpolation. Continue reading