Hi Wei-Hao,
whwang said:
Let me try to understand this. For R and B in a Bayer matrix, Bayer drizzle conceptually is just like normal 2x drizzle.
Bayer drizzle is just the same drizzle algorithm applied to CFA data. You normally perform a 1x Bayer drizzle, not 2x, because filling the Bayer pattern holes requires a *lot* of images. Filling Bayer holes plus the extra grid spacing in a 2x Bayer drizzle requires a really huge amount of data. For the same reason, Bayer drizzle is usually applied without any drop shrink (drop shrink factor = 1).
A 1x Bayer drizzle process can be used as a nice deBayering algorithm that works with the actual raw data without any interpolation. In this case there is no resolution improvement, but provided that you have enough frames to cover the image, the results should be better than a normal deBayering with interpolation such as VNG, AHD, etc.