With this investigation I hope to bring a view into how various low-level image sampling and related processes, including pixel binning, pixel skipping and Bayer demosaic algorithms, affect the image quality particularly with respect to the appearance of aliasing and Moiré.
The focus here is DSLR video systems, which typically use quality compromising methods to reduce the computational load when scaling down of the multi-MP sensors designed for still images. As the pixel count of those sensors increases the down-scaling becomes more demanding and computational heavy.
While newer DSLR cameras seem to have come a long way solving this problem, aliasing is still a main problem for many digital cameras, and it is not an easy tassk to find information on what underlying processes are. Having this information is crucial for the design of optical antialiasing filters (low pass filters) matching the various DSLR video cameras.
In this (rather long) article I will present simulation results from a range of different pixel binning, pixel skipping and demosaic schemes (btw. chroma subsampling no included) in order to see the effect on image quality and to see if it is possible to replicate the observed aliasing and Moiré of the Nikon d5100 best. This may also be used to evaluate the sampling method of other cameras, when using the same video test and compare with the simulation results. Read More…