FabScan v0.5.10 - Camera Robustness

v0.5.10 builds on the v0.5.9 follow-direction latch and focuses on making the USB camera path more forgiving on the LinuxCNC/FabScan machine.

What changed

• Default camera size changed from 1280 x 720 to 800 x 600.
• Saved legacy 1280 x 720 camera settings are migrated to 800 x 600 on load.
• Camera Capture and Camera Calibration now have resolution presets:
  • 800 x 600
  • 640 x 480
  • 1280 x 960
  • 1600 x 1200
  • 1280 x 720
• Camera status now reports requested size, actual size, backend, and format.
• Linux camera open explicitly requests the V4L2 backend.
• OpenCV asks for MJPG and a one-frame buffer when the backend supports it.
• Preview frame reads now happen in a background thread so slow/failing camera reads are less likely to freeze Tkinter.
• If no frames arrive, FabScan reports likely causes such as a metadata /dev/video node, unsupported resolution, busy camera, or disconnected camera.
• Preview PhotoImage objects are tied to the dialog window, and preview callbacks are cancelled on close.
• Removed confirmation popups for:
  • enabling jog controls
  • enabling controlled moves
  • running camera calibration

Motion safety checks remain in place: FabScan still refuses guarded motion unless LinuxCNC status is acceptable for that motion path. FabScan remains X/Y only: no Z, no torch, no plasma, and no cycle start.

Suggested camera settings

For the current microscope camera, start with:

Camera index: 0
Resolution: 800 x 600

Avoid 1280 x 720 unless the status line confirms the camera actually returns that size reliably.

Suggested line-follow settings from v0.5.9

Mode: Line center
Step: 0.050
Max correct: 0.010 or 0.015
Min conf: 55 or 60
Count: 10 to 50

If the first follow step goes the wrong way, change Direction and click Find Line / Edge again before running Follow N.