OSC and not debayer...
 
Share:
Notifications
Clear all

2022-08-17: APP 2.0.0-beta3 has been released !

Release notes

Download links per platform:

windows 2.0.0-beta3

macOS x86_64 2.0.0-beta3

macOS arm64 M1 2.0.0-beta3

Linux DEB 2.0.0-beta3

Linux RPM 2.0.0-beta3

OSC and not debayering


(@tsprecher)
Molecular Cloud Customer
Joined: 3 years ago
Posts: 6
Topic starter  

Is it possible to calibrate my lights (using darks, flats and darkflats) then register and not stack but save all registered files but not debayer them. I need these registered mono files for another program. I tried not checking the CFA box in tab 0 but that doesn't help. Using an ASI533MC Pro. I need to modify 150 files, is there a batch way to accomplish this task.


ReplyQuote
(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4934
 

Yes, I think you can do so using the "no interpolation" option in tab 0, for the used demosaic algorithm.


ReplyQuote
(@tsprecher)
Molecular Cloud Customer
Joined: 3 years ago
Posts: 6
Topic starter  

 When I click the "no interpolation" about 50% of my lights fail star analysis. Running a normal calibrate and register no lights fail analysis.


ReplyQuote
(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1816
 

@tsprecher It seems that this currently isn't possible. The interpolation drop down in the normalization tab doesn't allow for not debayering the frames. I'll pass this on to Mabula and will ask if that can be added.


ReplyQuote
(@tsprecher)
Molecular Cloud Customer
Joined: 3 years ago
Posts: 6
Topic starter  

FYI - The purpose of this exercise was to provide calibrated, registered non debayered frames from a OSC to a  program that will plot a light curve of exoplanets.

Thanks for the response.


ReplyQuote
(@mabula-admin)
Quasar Admin
Joined: 5 years ago
Posts: 3187
 

Hi Thomas @tsprecher,

That is simply not possible in APP at the moment.

The reason being is that the frames require debayering to not have bayer holes in the star intensity profiles so APP can accurately find the star centroids to have precise star alignment in registration. Without debayering this simply is not possible, without debayering you miss essential precision on the star profiles. The precision drops from about 0,1 to 0,5 pixel precision. Without debayering, you indeed will see that APP can't register them because of the bayer holes in the star intensity profiles.

Furthermore, the frames are registered, meaning the frames have been rotated, translated, scaled, corrected for optical distortion (so warped) etc... so the data is being resampled/interpolated to account for subpixel changes in all of these registration parameters combined.

A solution would be that APP would then allow you to save registered frames where only the bayer pixels are then filtered with a resampling/interpolation filter like Lanczos. But.... since the registration parameters will rotate, translate, scale, warp the resulting pixels, you can never again debayer that reliably. I would not know how... You could only do a naive and thus worse nearest neighbour on the pixels that were still zero. Realise that the registered bayer pixels because of the otate, translate, scale, warp will no longer have a nice Bayer pattern.. so no normal debayer algorithm can fix that.

Can I ask why you want that data not to be debayered? Is the convolution effect of debayering your concern?

Mabula


ReplyQuote
(@tsprecher)
Molecular Cloud Customer
Joined: 3 years ago
Posts: 6
Topic starter  

@mabula-admin

I am using two programs, AstroimageJ and HOPS. Both are designed to take images from a mono ccd camera and plot the small flux changes of a star recorded from an exoplanet transit. They only take darks, flats and bias for calibration. I want to use my ASI533MC OSC and darks, flats and darkflats for calibration and present mono images (could be 100 to 200 images) to these programs. So my thought process was to use APP to calibrate and register the images and bypass that part of the process in those programs. Maybe my thinking is off on how to do this as I am not an expert.

Thomas


ReplyQuote
(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1816
 

@tsprecher If those two software packages really only can process mono data then there is a possibility to prepare the images with APP. In tab 0 you can choose the "no interpolation" algorithm, which will force APP to treat all data as mono data. You can then process up to tab 5 Normalization and save the normalized images, which will be mono.

Screenshot 2022 06 23 at 14.01.43

Note, however, that an OSC camera has a different response than a mono camera, since the pixels are grouped together in Bayer matrices. This mean, as you probably know, that one pixel is sensitive to red, two to green and one to blue. This means that using "no interpolation" will generate mono images but not with the same response as a true mono camera. For instance, red or blue stars may look brighter in the OSC mono images than in true mono images, depending on the filter used in the mono camera.


ReplyQuote
(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1816
 

@tsprecher Out of curiosity, do you have a URL for HOPS? I have been searching online and cannot seem to find it.


ReplyQuote
(@tsprecher)
Molecular Cloud Customer
Joined: 3 years ago
Posts: 6
Topic starter  

@wvreeven 

Link to HOPS

https://www.exoworldsspies.com/en/software/

Note: I have used my raw images and calibration frames with both programs and obtained results. I just want to see if calibrating and registering them differently will provide better results, as sometimes some of the raw images are rejected. Also, APP wipes out a lot of the fits header info which is needed.

Thomas


ReplyQuote
(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1816
 
Posted by: @tsprecher

Link to HOPS

https://www.exoworldsspies.com/en/software/

Thanks. I found that site but wasn't sure if it was the same software as you meant.


ReplyQuote
(@tsprecher)
Molecular Cloud Customer
Joined: 3 years ago
Posts: 6
Topic starter  

@wvreeven 

I tried running APP again using the "NO Interpolation" and was successful in obtaining gray 16 bit mono calibrated/registered images with a different data set. (I tried this initially as Vincent suggested-somehow I screwed up!)  Now I need to start from scratch with a data set that has more exposure and see if these other programs will except the data. Thanks for all the help!


ReplyQuote
Share: