SEEKING ADVICE

[Jan]

Hi guys, I have a small problem here. I normally use batch preprocessing script. Suddenly, the resulting calibrated images have really strange colours - shifted towards the red and when I align channels eg in histogram transform, the result has neutral, but slightly shifted colours, very hard to saturate and when saturated, it is just not it. I tried to reset al values to default, but did not help.

I have to ad, that i have precessed this data before and there was no problem (now i just wanted to experiment with value settings and integration settings..). Also I took another data from other folder and everything was fine, result was awsome. Does anyone have idea what can be the problem? THANKS!

[Carlos Milovic]

I'll assume that you are using a DSLR. Check your options for opening the raw format. Make sure to select "no black point compensation" and create a bayered image (I use the grayscale one, since it uses less memory).

[georg.viehoever]

You may also want to try BackgroundNeutralization and ColorCalibration.

[Jan]

A little misunderstanding here, actually it has nothing to do with any backround color calibration, the image has just totally cast towards red, stars LOOK red after preprocessing, and I wasnnot experiencing this before even with the same set of image files.

I have double checked by your advice Carlos, and all settings seem all right. As I said, other image sets of cr2 turn out normally. Just one set of data is giving me these results- but the same data weree fine few weeks ago.

Bayered images look 1A+, nicely calibrated. But during debayerisation the image just turns out incorrectly. I have even checked again correct debayer settings, even changed them, but no change..

I am sure it will be one tick somewhere, but can not figure out what it can be...

[Carlos Milovic]

Maybe it is something related to the flats (just guessing).

[Jan]

Well actually it should not be the probem with darks, because as I said above, when I processed this set of data before, there was no problem at including calibration files.. Dont know what to do with..:-)

[georg.viehoever]

Well actually it should not be the probem with darks, because as I said above, when I processed this set of data before, there was no problem at including calibration files.. Dont know what to do with..:-)

Whatever the root cause of the problem is: you should be able to get rid of the color cast with the tools I mentioned above.
Georg

[Jan]

Georg I appreciate your advice but color cast generally is not what I need to solve, I need to solve something wrong happening during calibration. Of course I did try to balance colours, but as I have written in the original question, this was ok EXCEPT that saturation was weak after that and increasing saturation showed the colours are just not what I normally get out of the script. To conclude- of course there are other means hiw to get rid of the problem, by I need to find the root, otherwise I will just be trying to improve images crippeled by wrong something and the result will be even more crippeled This is why I really need to find out why things which did work before do not work now;) Inwould compare it to the situation when you have images with weak sharpness- or you use sharpening tools or you look for better technique to focus your images- I look for the second one;)

[chris.bailey]

Does a single uncalibrated image brought into PI and manually debayered look ok?

Do you have dark optimisation switched on? I dont find it works as well with OSC images as it does with mono frames.

Good though the BPP script is, I much prefer to calibrate, cosmetic correct, debayer, register and stack as separate processes. I run blink before stacking to get rid of any suspect frames and check a sample at each stage to be sure things are as I would expect them.

Chris