I think a defect map would be sufficient. It needs to be applied to the lights after calibration and before debayer and register, needs to be able to handle CFA images, and should be able to handle multiple neighboring defect pixels. The current DefectMap tool lacks CFA capability, the CosmeticCorrection process has CFA and works nicely using the Auto Detect filter...probably similar to what DSS does (but I could not get MasterDark based defect detection working for some reason).
Defect map handling can be done with the current tools, but since it needs to be done right in the middle of the calibration process, it is not easily integrated into the flow of the current script.
To illustrate the need: I usually need defect maps for my wide fields, because my mount does not do enough automatic dithering (otherwise called periodic error/tracking error
) for short focal lengths. Integration of the calibrated stack clearly shows hot pixels. When I activate rejection to a sufficient degree, I loose SNR. See screenshot of integration of 52 lights, each 120 seconds@85mm:
- left: stacking without rejection and defect map: High SNR, but traces from hot pixels in red and green
Gaussian noise estimates:
?sR = 1.076e-004
?sG = 7.923e-005
?sB = 7.929e-005
Reference SNR increments:
??s0R = 4.9153
??s0G = 6.2299
??s0B = 6.2170
Average SNR increments:
??sR = 4.9063
??sG = 6.3918
??sB = 6.3783
- center: stacking with linear fit rejection (sigma high=3): Lower SNR, no traces. Also relatively slow (2353 sec)
Gaussian noise estimates:
?sR = 1.317e-004
?sG = 8.875e-005
?sB = 8.991e-005
Reference SNR increments:
??s0R = 3.9821
??s0G = 5.5467
??s0B = 5.4732
Average SNR increments:
??sR = 3.9747
??sG = 5.6908
??sB = 5.6152
- right: stacking with defect map, using Cosmetic correction with Autodetect, Hot Sigma 3): Higher SNR, no traces, fast (281 secs)
Gaussian noise estimates:
?sR = 1.076e-004
?sG = 7.923e-005
?sB = 7.929e-005
Reference SNR increments:
??s0R = 4.9153
??s0G = 6.2299
??s0B = 6.2170
Average SNR increments:
??sR = 4.9063
??sG = 6.3918
??sB = 6.3783
Georg