Implement bias and dark frame subtraction
Implement bias and dark frame subtraction as described nicely for example here:
This needs to be done very early in the pipeline, one of the comments suggests (and includes an example) even before demosaic.
#3 Updated by Ed Halley over 3 years ago
Would love to see traction on this -- the DNG files that come out of a recent popular drone, DJI Mavic Pro, have a very strong and consistent red bias in the center 30% of the frame. If the user could take samples in a controlled lighting situation (a flat field image), then subtract the bias from all compatible frames (dimensions, camera identifier, etc.), it would save a ton of time.
(Updated: the new DJI Mavic Pro camera has camera model "FC220" maker "DJI" in it. I don't have any physical color targets like Gretag or it8 to help with the new camera support.)
#4 Updated by Albert Jasinski over 2 years ago
This feature is essential for astro photographers and another people using long exposures.
Subtracting dark frame from image gives really good results.
Of course most of cameras have this feature built in. But using this option in cameras double exposure time - that is really bad, specially when you doing a time lapse.
#5 Updated by Raphaël Monat almost 2 years ago
I completely agree with Albert Jasinski. I've shot quite a few exposures of the milky way, and to process them I'm currently using ufraw to perform the dark frame subtraction between two raw files, before converting this into TIFF, and importing this into Darktable...
I'm just wondering: is this feature supposed to be added in darktable or in the raw decoder (rawspeed)?