SharpCap Forums

Trying to use feature tracking on the moon with my Player One Saturn C ( IMX553 ) cam I get some bright area on some image when capturing in SER format

I am using SharpCap 4.1.12025.0

Here is an image from a faulty SER file
Regards
Bertrand

Hi Bertrand,

that's odd. I can see from the camera settings that you had a bit of display strech enabled, which might have been about the sort of stretch that could make the bright area. However, the display stretch is not supposed to apply to the saved image and even if it did, I'm not sure how it could affect only part of the displayed image.

Can you tell me a bit more about what settings you were using in feature tracking? Maybe knowing about that setup would help. Also, did you have anything else activated in SharpCap at the time when you were capturing (any tools like histogram, etc).

cheers,

Robin

As I can remember Histogram tool was not activated.

Feature tracking options were
Use camera roi
Use image feature
Highlight feature / ...

I can send you the SharpCap log file and the timestamp of the recorded ser file or the ser file.

Regards
Bertrand

Hi Bertrand,

if possible the log and the ser file would be helpful to try to see if anything of interest in the log ties in with appearance of the problem in the SER file.

thanks,

Robin

Here is the link to the SER and log files

https://drive.google.com/drive/folders/ ... drive_link

Issue could be seen frame 66 using SER Player

Hi,

the share wasn't set up for public access, so I have just requested access to the file - once you approve that I will be able to download it.

cheers,

Robin

Approved

Hi Bertrand,

thanks for sharing the files - I think I understand a bit about what is going on now...

Looking at the bright frames in the image, they seem to occur regularly about every 115 frames (at frames 66, 189, 297, 412, 526, 641, etc). At the frame rate of 87fps of the file, that corresponds to one bad frame roughly every 1.3 seconds.

Looking at the guiding log for that imaging session (GuidingLog_2024-04-20T02_11_36-17180.log), you can see that at about the time of the capture starting (02:12:45) , guiding commands to move the mount were being sent about every 1.3 seconds.

How are the capture camera and the mount connected to the PC? If you are using a USB hub (or even two adjacent USB ports that could be on an internal hub), it might bm e the USB traffic to command the mount is causing issues with the regular flow of frames from the camera, causing the intermittent glitched frames.

If you look closely at the glitched frames (ie frame 641) you will see that there is also some downward/sideways movement of the image in the bad frames and some bad data at the top of the frame too. This all tends to tie in with a glitch in the data transfer (effectively some extra data either inserted or missing at the start of the frame). I can't think of anything in the SharpCap feature tracking code that is likely to cause this array of symptoms.

I would try bringing the USB cable from the camera back to a separate port on the PC without sharing it with other devices if you can to see if that helps.

cheers,

Robin

Hello,

I was using a Dobsonian télescope on an equatorial platform. So there is no connection between the mount and the computer.

Except using the virtual "telescope simulator for .net" from ASCOM platform in order to see the result of Sharpcap plate solving in Stelarium software.

This is why I was trying to use the ROI feature tracking.

So normally there is no command send to the mount but only move the ROI in order to keep the feature centered.

Using same setup during the same night I was able to capture other SER file whith out any trouble.

I don't use any USB hub, the camera was directly connected to the PC.

If you need extra info/data or other test please let me know

TIA
Bertrand

Ah, OK, that makes even more sense then I think...

The glitched frames are the ones when the camera is responding to the ROI change - I suspect if you move the ROI area around manually you will see the same thing happening from time to time.

I'm not sure that there is anything to be done here - depending on camera brand/model, this sort of thing can happen for ROI changes or for changes of other settings like gain or exposure.

cheers,

Robin