What is Debayering?
Did you know that more than 50% of your digital image is not recorded but is calculated via algorithms? And this occurs right in the beginning in the first step of image processing.
Debayering is the first step of a digital image processing a raw image. Previously, video cameras had three different sensors for each color: Red, Green, Blue (RGB). There is a prism inside the camera that splits the image into these specific color components, so all the three sensors are exposed to the same image at the same time.
For each pixel, there is a precise recording of the RGB colors. Celluloid film works in the same manner. It has three layers with a light-sensitive grain, one for every color.
With the introduction of large diameter CMOS chips, the three color chips are placed next to each other, not on top of each other. (Because creating large prisms with high quality is proven to be tricky).
How Are the RGB Values Created?
In order to make the RGB values for each pixel location, a Bayer interpolation algorithm is created. This algorithm finds the volume of from the nearest surrounding pixels. A consequence of this process is that the resolution is decreased, as the color information is an approximation of a few pieces of information.
A few unexpected results can occur from these color combinations. A frequent issue is called the zipper artifacts. This occurs through bilinear debayering which is the easiest form of making values of each pixel location by calculating the average value of all the nearby pixels.
Visually this causes lines and edges with a chessboard or zipper look. Another outcome is moirés or false color edges. While this is a problem in still images, they are more evident in movie footage.
Various debayering algorithms were made to address these issues. In fact, most post-production software and cameras have their own source of proprietary debayering algorithms, and some of them are processing and analyzing each frame multiple times.
Debayering algorithms in post-production can be based on certain steps of complex creations, given that they don’t have to conduct the renderings in real time in contrast to the cameras.
Line Detection
Line detection which is a part of debayering is a method used to sharpen lines and edges. However, this can result in the images having an artificially sharp appearance. Also, it might take out the original camera noise and make a strange grain structure resulting in an artificial look on human skin.
Most manufacturers use debayering to address the issues, designed for internal image processing and their. Most of the aliasing is caused by missing a low pass filter than indefinite debayering. However, the artificial sharpness is an issue that’s responsible by the unnatural look the camera makes.
Conclusion
To conclude, debayering software can be used to improve the enhance the quality of the image. Through using this software, your colors will be corrected, and the lighting is accurate. Ultimately, use debayering to bring your images to life.
