Problem with debayering

[Magnus L]

Hi again!

Another issue from me: I'm not very used to OSC cameras, but for various reasons, I'd need to use one for photometry. So I try to debayering and then extract the G channel. But the demosaic seems to be strange. Whichever pattern I try, it is not well debayered. According to fits header, the pattern should be RGGB, but not better than any other. The image is from an ASI294pro, and it is bin 3x3. Fits image is attached. What am I missing?

Magnus

[han.k]

Extracting the green channel will only work for binning 1x1. Binning 2x2 or 3x3 will combine the red, green and blue sensitive pixels and information will be lost.

Debayering should also not be done. Every four RGGB sensitive pixels will be converted to a three layer RGB image. You need the raw fits files.

Just do the following.

1) Take 1x1 binning images. Load them in the photometry tab.
2) Optional take 1x1 darks, flats and flat darks and load them in the corresponding tab.
3)Optional select in tab photometry the files with CTRL+A, call up the popup menu and select calibrate.
4)Select in tab photometry the files with CTRL+A, call up the popup menu (right mouse button) to extract the green channel. The files will be replaced by file with the green channel only. Size will be 50x50%. of the original. So RGGB become (G+G)/2 is a single green sensitive pixel. So surface is 1/4 of original.

Han

[Magnus L]

Thanks!
Magnus

[Magnus L]

Hi!

Following up on this:

I'm trying to do photometry with a color camera. I captre an image with bin 1x1, then in the photometry tab right click on it and choos "extract green channel". Then I get one now image. Howwer, in the video where you demonstrate this, there pops up a warning that 2 files will be created. But I only get one file. Am I missing something? I mean, there are 2 green pixels (RGGB pattern).

Magnus

[han.k]

In the current version for each RGGB pattern so of each 2x2 pixels the two green pixels are averaged. It produces then only one file with half width and half height of the original.

Han

[Magnus L]

Thanks! :)
Magnus