Experimenting with Post processing - RAW Support - AutoStrech - HLVG - SCNR #753
Replies: 4 comments 1 reply
-
@AstroFrank, do you have a ZWO or RPiHQ camera? You'd have to look at the "convert" documentation to know what -sigmoidal-contrast does. We use that command because we're already using it for other things (crop, resize, etc.). You may want to save the image before stretching to compare it to the after stretched image to see if that's where your green is coming from. Either way, you may be able to get rid of it by playing with the red and blue balance. |
Beta Was this translation helpful? Give feedback.
-
Hello Eric, I have a modified RPIHQ NOIR from Arducam. it's the same IMX477 sensor but with a mechanical IR Cut that gets removed automatically in low light. It works just the same with the SPI on a RPI 4b. Note the image below, through a window. I haven't receive the acrylic dome just yet so simply running some test through the dirty Hamshack window. The lens is 120° so I am hoping to avoid the ground completely once it's pointing at Zenith. Everything on manual: exposure is 1 minute, gain is 16, 50 brightness, 50 gamma, red is 1.2 and blue is 2. Autostrech amount is 6 and mid point is 40%. Do you think this might be caused by no IR filter? But lets face it, the image does have a green cast but it is still fantastic. I could expiriment with something like Siril. Any reccomendations? |
Beta Was this translation helpful? Give feedback.
-
@AstroFrank, someone posted they got good color results with red: 3.24, blue: 1.47, but that was on a RPiHQ camera. I think I read on the Raspberry Pi forums that using the NOIR gives funky colors, which makes sense if IR light is being recorded. Do your red and blue settings produce nice images during the day when the IR filter is in place? If you get to the point where you have nice colored daytime images and nice colored nighttime images, but using different red and blue settings, we could look at allowing you to specify different settings for day and night. |
Beta Was this translation helpful? Give feedback.
-
@ice8lue Yes, it is on our to-so list, but don't know when we will get to it. There will be separate day and night settings for auto color balance, red, and blue. Eric |
Beta Was this translation helpful? Give feedback.
-
Hello,
I was just wondering if anyone has attempted to modify the post processing methods. I am not sure what algo is used for auto strech, I am getting lots of green and was wondering if playing with RPIHQ raw might help improve it in post. I use HLVG and SCNR with the full telescope post and I thought perhaps this would be interesting here.
Roger Clark (Clark vision) has a CLI rnc-color-strech that looks interesting: https://clarkvision.com/articles/astrophotography.software/rnc-color-stretch/rnc-color-stretch-v0.975
There are a quite a few Linux CLI astro tools that could be easily added I think.
What do you folks think?
Beta Was this translation helpful? Give feedback.
All reactions