SharpCap histogram diagonal bar not present

[mihai_mail_ro]

Hi
I am running latest SH ver. with 3 different cameras (two SVBony and one PlayerOne) and in Live View under the right side main menu "Display Hystogram Stretch" the diagonal line is missing or is at the bottom so I cannot stretch the histogram. If I display the histogram in live stacking mode it is present but only in the specific window.
This is after I have uninstalled and reinstalled the SH latest version (before that all 3 vertical bars were stuck on the right side of the histogram).

Thanks for any help.

BR
Mihai

[admin]

Hi Mihai,

that's odd - it's working for me in the latest version (4.1.14120; 64-bit). From your description it sounds as though you are able to adjust the position of the vertical yellow bars, but not only is there no curve showing up in the user interface, but there is no effect on the displayed image either - is that correct?

Actually, zooming in on your screenshot, it looks like the yellow line might be running along the bottom of the graph (ie zero at all points), rather than taking its usual curve - I can certainly see something yellow at the bottom of the graph that doesn't seem to be present if I take a screenshot of the same area on my PC. Also your displayed image is black... So maybe the curve is being miscalculated as all zeros.

Does it help to press the 'reset' button to the right of the histogram? - that's the one with the anticlockwise arrow on it... That should reset the stretch back to default. I'm wondering if somehow you have ended up with the three yellow markers out of order (shouldn't be possible, but maybe somehow). If they are out of order then the resulting curve could be very odd indeed.

cheers,

Robin

[mihai_mail_ro]

Hi, Robin
thanks for your reply
You are correct, adjusting the vertical bars has no effect on image.
The image in the main window is not completely black, I can increase the exposure and it is working as expected except I cannot do auto stretch from the right side menu.
I have tried all buttons in this window with no effect.
I have SharpCap on a laptop and it is working fine.
I have copied the whole SH directory from the laptop to the PC (after renaming the PC Sh directory) and it does not work
I assume there is something corrupted in my WIN10 but I am not sure what resources/libraries is using SharpCap so I need to reinstall them too.
Maybe you can disclose what is the specific programming software resource that is involved in this particular "Display Histogram Stretch window"?
Is there any logging that can help?

Thank you

[admin]

Hi,

the fact that the adjustments have no effect on the image as well as the line not showing would tend to suggest that somehow the code to activate the stretch is not working correctly - not activating or encountering a problem and giving up trying to do the stretch. I did look at this code yesterday when answering your previous message and couldn't see anything that looked like it could cause this, but I must have missed something.

Modern versions of SharpCap are almost entirely self-contained... Everything they need to run is inside the installation folder, so if you uninstall and then re-install, it should replace all the files and fix any problems if there were missing/corrupted files causing this.

There are a few things you can try...

1) Go back to an older version of SharpCap to see if the problem goes away. Particularly if you have a version that you know worked before and try that it will give interesting results... If it fixes the problem then we know it is something changed in the latest version that is affecting you. If it doesn't fix the problem then it is probably something to do with SharpCap's settings.

2) Reset all camera setting to default by opening the camera with CTRL pressed down - this stops SharpCap from re-loading previously used camera settings

3) Reset all of SharpCap's settings to default (there are options to do this at the bottom of the main settings window. You can also export your current settings before doing this, meaning that you can re-import them if the reset doesn't help).

4) Try turning off graphics card acceleration in the first page of the settings - I don't think this is likely to help in your situation , but worth a try.

cheers,

Robin

[mihai_mail_ro]

Thank for your reply
I will try them later today but reinstalling it didn't worked.
Also, when trying to download older versions (4.0 or 3.x) I got an error about the checksum.
Is there any way to download them still?
Best regards
Mihai

[mihai_mail_ro]

Hi, Robin
the CTRL pressed down during SharpCap starting and camera opening solved the issue.
Pressing CTRL on;y when opening the camera did not solved the issue.
I do not know what is the reason but it is great that you found the solution.

Thank you very much
BR
Mihai

[mihai_mail_ro]

I have managed to reproduce the errors by reloading previous saved camera profiles.
I have compared good and bad profiles and the difference is in the following parameters that are not properly computed is some cases
NegativeDisplay=0
Display Black Point=NaN
Display MidTone Point=NaN
Display White Point=NaN

Now I have done a camera parameters reset and saved again with good profiles for a later use.

[admin]

Ah, brilliant - thanks for digging that out. 'NaN' means 'not a number' - it's the result you get on a computer when you divide zero by zero. I guess that value probably came out of the auto stretch calculation at some point and then it got saved into the 'autosave' or other profile and kept being loaded up again and again. Once you have that value going into a calculation, the values that come out (like the shape of the curve, or the stretch calculation) are also going to be wrong.

I try to work out how that got generated in the first place and address that, and also stop that value being loaded back if it does get saved for some reason.

cheers,

Robin