Horizontal banding in image

Discussion of using SharpCap for Deep Sky Imaging
Moonstruck
Posts: 112
Joined: Tue Aug 17, 2021 4:34 pm

Re: Horizontal banding in image

#11

Post by Moonstruck »

Thanks very much for diagnosing the banding problem. I really appreciate it! I have just a few more related questions:

1. I just uploaded the most recent version of sharpcap (4.0.8861.0, 32-bit, released very recently). You mentioned that this version makes it less likely for the banding suppression feature to cause this sort of problem. Since I downloaded this new version, do I still need to go through the banding settings calibration?

2. If I don't have time to go through the calibration process, will turning the banding suppression down to zero, as you suggested, prevent the banding from appearing again?

3. Can the banding suppression setting be changed if not connected to a camera? (not sure if I have to set up my camera and scope to change the setting).

4. You mentioned the possibility running the frames through the folder monitor camera to get rid of the banding in the frames I already took, in order to be able to use those frames. Can you please let me know how to use the folder monitor camera, and how I would then save the changed files? I have never used it before. I looked in the menu of the Sharpcap user guide, but I didnt see any instructions for use of the folder monitor camera, but maybe I just missed it.

Sorry for all these questions, and thanks again for your help.
User avatar
turfpit
Posts: 1779
Joined: Mon Feb 13, 2017 8:13 pm
Location: UK
Contact:

Re: Horizontal banding in image

#12

Post by turfpit »

John

Some answers.

1. If banding suppression is set to zero, the functionality is in effect disabled (from the manual).
2. See answer above.
3. You will only see the settings if the camera is connected. They appear under Misc Controls on the right hand side of the screen (scroll down needed).
4. Never used folder monitor so cannot help with that.

To reset the banding suppression value can be done with the camera plugged directly into the capture laptop, no telescope needed. This could be done in the house.

Dave
User avatar
admin
Site Admin
Posts: 13173
Joined: Sat Feb 11, 2017 3:52 pm
Location: Vale of the White Horse, UK
Contact:

Re: Horizontal banding in image

#13

Post by admin »

Hi,

Just to fill in on the folder monitor camera - tricky to find it in the manual, but it is there : https://docs.sharpcap.co.uk/4.0/#Virtual%20Cameras

cheers,

Robin
vk4tnt
Posts: 10
Joined: Fri Mar 02, 2018 5:30 am
Location: Brisbane

Re: Horizontal banding in image

#14

Post by vk4tnt »

Hi Robin,
I was able to look at some comet images I took with a QHY174 a few weeks ago. Your method shows nicely how the bands disappear using the Band Suppression 35 and Threshold 10 on my pre recorded files with the Folder monitor Camera. Unfortunately, I can's find a reference how to save the output files that show on my screen. The files in the original directory are unchanged and no new directory is created. Could you please advise how we can save files that are pre-processed using your method?
Thank you in advance,
Renato
User avatar
admin
Site Admin
Posts: 13173
Joined: Sat Feb 11, 2017 3:52 pm
Location: Vale of the White Horse, UK
Contact:

Re: Horizontal banding in image

#15

Post by admin »

Hi Renato,

just use the 'Start Capture' or 'Snapshot' buttons in SharpCap as you would to save images when using a real camera - that will re-save the processed images. Depending on the output format you have set in SharpCap you can get them as individual FITS files, or an SER file with all the frames in, or some other option.

cheers,

Robin
vk4tnt
Posts: 10
Joined: Fri Mar 02, 2018 5:30 am
Location: Brisbane

Re: Horizontal banding in image

#16

Post by vk4tnt »

Hi Robin,
Thank you for your quick reply. Yes, that was easy enough to start recording and after that to start the pre-processing sequence. One thing though, it looses the first frame, but I think that's not too critical. Could you please add the procedure in the user manual? I think that would help a lot of people.
Thanks again,
Renato
User avatar
admin
Site Admin
Posts: 13173
Joined: Sat Feb 11, 2017 3:52 pm
Location: Vale of the White Horse, UK
Contact:

Re: Horizontal banding in image

#17

Post by admin »

Hi Renato,

yes, I am planning on a documentation update sometime later this year, so I will try to cover that sort of thing. The latest updates to SharpCap have a button to replay the current frame in the folder monitor camera, which helps with the missing frame problem (use the replay button then the play button).

cheers,

Robin
pacraven
Posts: 1
Joined: Wed Aug 23, 2023 11:20 am

Re: Horizontal banding in image

#18

Post by pacraven »

Hi - not sure whether this thread is still open but I recently had this horizontal banding problem with my ZWO ASIMC294Pro.
It wasn't the banding supression setting in SharpCap.

However, what seemed to solve it was moving the transformer (i.e. part of the power cable for my EQ6 mount) away from the camera. It must have been producing an electrical signal which interfered with the ZWO camera image. I moved the transformer down from the table (where it was near the camera) to the ground and the banding problem disappeared.
User avatar
admin
Site Admin
Posts: 13173
Joined: Sat Feb 11, 2017 3:52 pm
Location: Vale of the White Horse, UK
Contact:

Re: Horizontal banding in image

#19

Post by admin »

Hi,

thanks for sharing - that's good information. This very much ties in with my belief that the banding is a result of variation (noise) in the voltages within the camera circuitry. I suspect with the power supply nearby the camera (or perhaps the USB cable to the camera) was picking up some interference leading to additional banding.

cheers,

Robin
Post Reply