Splitting Raw files

Hi Guido,

Thank you for your question.

No not really. The data of your EOS D70 is bayer CFA data. You want to calibrate the CFA data before doing any debayering.

If you were to split your lights, flats, etc..  then these frames will be debayered so you can get the complete separated color channels. If you then use those for calibration, then each frame has undergone debayering and will therefore have introduced debayer noise. The debayer process introduces noise and possibly even artefacts. So it is much recommended to calibrate the light frame's CFA data with only CFA pixels of the calibration frames (which APP does automatically for you). After calibration, APP automatically debayers your CFA calibrated data for all processses from 3) Analyse stars.

If in 2) you save the calibrated frames (something I always do, so I can keep the calibrated frames and possibly use them in later projects or after having shot more data of a single object), then these are saved as CFA data still. So the frames aren't debayered yet. Only if you use the option "align channels" to remove chromatic aberration in your RGB data, then the calibrated frames are debayered before applying the channel alignment.

Splitting the channels as part of calibration, would mean that the data is still calibrated on the CFA pixels, before splitting the CFA calibrated data. The splitted data would be needed if you want to combine the data with monochrome filter data. So then you can integrate your DSLR Red data with data shot with a monochrome camera and a red filter.

Let me know if this is clear 😉

Mabula

Thanks Mabula,

So if i understand it well 

1) always save the calibrated frames (they are not debayered), except when using 'align channels'. 

2) splitting as a part of calibration gives 3 channels calibrated on the CFA level, and can be used later to combine with monocrome frames, after debayering?

3) We need to calibrated a second time the calibrated frames using splitting channels if we want to do this some time later?

Is this correct?

Guido

Posted by: Guido Van Gheluwe

Thanks Mabula,

So if i understand it well 

1) always save the calibrated frames (they are not debayered), except when using 'align channels'. 

2) splitting as a part of calibration gives 3 channels calibrated on the CFA level, and can be used later to combine with monocrome frames, after debayering?

3) We need to calibrated a second time the calibrated frames using splitting channels if we want to do this some time later?

Is this correct?

Guido

 

You're welcome Guido,

1) I always save (and store) the calibrated frames for possible later use. I find it much easier and I can free up storage by removing the calibration frames that were needed to calibrate the data as well. But saving them isn't required, it's just what you find most practical I think.

2) yes, if you save the data while splitting the channels, it's calibrated on the CFA level but the data will be debayered so you will get the separate channels without the CFA holes. So then the data can be directly combined with other data of the same color/channel.

3) Yes, if you have calibrated the data before, but didn't split it. Then to split it, load the calibrated frames and just save calibrated frames with split channels enabled to debayer and split them 😉

Kind regards,

Mabula