SharpCap Forums

Hi Robin,

I'm seeing uncorrected hot pixels in my livestack when I'm using the ROI for my camera. I assumed that SC would pick the matching sub-area from my master dark, but alas it seems it's not the case.

Config: ASI294MM in 11Mpix mode

Example with ROI : Full frame:

Hi,

I can't quite tell from the screenshots, but I am wondering if it is applying *any* dark subtraction, or if it is applying something but messing up the alignment so that the hot pixels are not being removed properly (but the average value drops).

There are a number of checks that have to be satisfied to use the ROI cut out feature - things like the dark frame must be at the full resolution of the camera, and the maximum of the pan control plus the width of the current frame must equal the width of the dark frame, and so on. These are all designed to ensure that SharpCap can properly work out the area to cut from the dark frame.

Sadly, right now, if one of the checks isn't satisfied, there is no logging of what went wrong (I guess this has largely worked as intended for some time, since I haven't seen this before). I will add logging for the next update so that we can find out what check is going wrong. I do wonder about the resolution checks, since the ASI294MM is 'weird' in having two different read modes with different resolutions - maybe that is triggering the problem.

cheers,

Robin

Hi Robin,

thanks for looking into the issue.

admin wrote: Thu Mar 06, 2025 2:35 pm I do wonder about the resolution checks, since the ASI294MM is 'weird' in having two different read modes with different resolutions - maybe that is triggering the problem.

I was thinking about the same thing, another 294MM weirdness (I vaguely remember past issues with calibration files that suddenly became incompatible with lights, due to the way the driver was reporting resolutions - it had to do with resolution not being a multiple of 4 pixels or something similar)

Hi,

yes, it's going to be something like that - unfortunately I don't have a 294 MM to test with, so best to see what the new logging reveals in the next update - it would also be good if you could note down some values :

* The maximum resolution available in your 11 megapixel mode
* The ROI resolution you are using
* The maximum values of the pan/tilt controls when you are in ROI

cheers,

Robin

Hi Robin,

admin wrote: Fri Mar 07, 2025 1:35 pm * The maximum values of the pan/tilt controls when you are in ROI

do you mean "the upper limit of what can be set" in the Pan/Tilt numeric fields?

Hi,

yes, that's correct - the largest value you can set.

cheers,

Robin

Hi Robin,

here you go:
* The maximum resolution available in your 11 megapixel mode: 4144 x 2822
* The ROI resolution you are using : 1024 x 768 in the current example
* The maximum values of the pan/tilt controls when you are in ROI: max pan = 3120, max tilt = 2054

The log is too large to add as an attachment here, so here's a shared link: https://1drv.ms/u/c/ba60ecfe9474a667/EW ... g?e=2WMV9k

Hi,

OK, those values look correct in that adding the width of the ROI to the max pan gives the max width and similarly for the height. However, I do wonder if there might be an issue here due to the ASI294MM having the two different read modes - maybe the code is incorrectly checking against the max width/height for the larget 47Megapixel read mode, rather than the max for the 11Mp mode. I will have a look and see if anything like that is going on.

cheers,

Robin