Issue After Changing Detector Settings

[gbzan]

Dear WebCT Development Team,
I changed the detector settings, including the number of pixels and pixel size. After that, the projection view at the bottom turned yellow (as shown in the first image). I'm not sure why this happened.

When I attempted to perform a projection capture, an error message appeared, and the projection simulation did not run (as shown in the second image). I checked the log file but couldn’t find any useful information.

Could you please help me understand what might be causing this issue?

Thanks in advance!

[WYVERN2742]

The yellow is a helpful indicator showing where the detector would expand and changes with detector size #102 (see https://github.com/WebxCT/WebCT/releases/tag/v1.0.0 for an animation)

As for the error, currently the feedback on the user-side for errors is lacking with an open issue: #52, I recommend looking at the console window WebCT opens as that'll have more informative errors.

I suspect you are using a detector size that is too large for your graphics card, that doesn't support 2000 x 3000 textures. The use of detector binning will solve this as it'll simulate the images at a lower resolution.

I'm currently coordinating with the developer of gVXR so I can show your max supported image size on the UI, preventing this issue.

[gbzan]

Thanks for your response. I think you’re right—the issue might have been caused by the detector size being too large for the graphics card. Actually, I have two GPU on my computer, I think it only uses one GPU.

I changed the pixel size from 500 µm to 50 µm while keeping the same pixel matrix (500×600), and the error no longer appeared.

However, I encountered another issue. After changing the pixel size to 50 µm, I tried adjusting the Global Scaling from 1 to 0.1 to match the smaller field of view. But the sample image didn’t appear in the projection view, as shown in the attached picture. It seems that the Global Scaling setting either didn’t take effect or I may have configured it incorrectly.

Could you advise on whether I’m using the Global Scaling setting properly, or if this could be another bug?

Thanks in advance!

[gbzan]

I ran one more test.
When I changed only the Global Scaling value from 1 to 0.1 without changing other settings, the sample was scaled as expected, but its position also shifted. This behavior is different from what I expected—I assumed only the size would change, not the position. Is this the normal setting?

[WYVERN2742]

Hi, in the first case it looks like the object has moved completely outside of the FoV. Ideally the global scaling should not change the position of the object at all. I assume you have no detector translation?

If you are able, it'll be much appreciated if you can send a copy of your WebCT config (white cog on the bottom left -> export as JSON -> Attach here). This isn't an issue I've encountered before, even when using global scaling.

When it comes to using fewer pixels on the detector, I normally recommend entering your normal scanner parameters (2000x3000, 50um, etc) and use the detector binning box. It basically increases the pixel size to reduce resolution, however other settings are compensated (flux, Detector PSF) this should make it possible to use without global scaling for now.

Sorry about all the trouble 😕

[gbzan]

Thanks for your quick reply.
I didn't have the detector translation.
I changed the pixel size from 500 µm to 50 µm, and changed the detector matrix as 3600*300 with 3x3 binnings. By the way why there is no option of 2X2 binning. We use 2X2 in our setup.

Attached is the my WebCT config.
Config-WebCT.json

[gbzan]

I ran one more test to check the "global scaling".
I only changed the Global Scaling from 1 to 0.1 without changing any other default settings. The object has moved towards the edge of FoV, attached is the WebCT config file.

Config-WebCT_onlyChangeGlobalScaleTo_0p1.json

[WYVERN2742]

Thanks for the config! I can confirm I can reproduce the issue locally with the latest version, I'll open an issue to fix it.

I'm unsure what could've changed, so will have to do a deeper debug. Thanks for catching this!

[gbzan]

Thank you. Looking forwards to seeing the new version.
I want to share another advanced simulator which has lots of great features. However, it is a commercial software which costs a lot. Maybe you can learn some key features from there.
https://www.youtube.com/watch?v=o7RofupiNyE&list=PLBFzzcGCQywa5aBAue1B7yPgvJB4-9WRR&index=1&t=1s&ab_channel=Novitom