Reset calibration without resinstall?

[RodgerHoll]

I have had a sandbox running for about 9 months, it is designed to be portable so it has moved around between schools and events. Recently I rebuilt the tower that holds the Project and Sensor so that it is easier to transport and provides much better stability (less shaking when bumped). This changed the geometry of the box / project / sensor.

When I went through the calibration process with the new tower arrangement, everything worked out fine, good coverage of sensor and projector, good alignment, calibration within a millimeter or 2, However…

When running the sandbox proper, the terrain was shifted about 3cm for where it should have been.
I tried redoing the calibration, rechecked alignments etc. all fine. I even made sure I had the latest version of the software, Which I was already using. checked the keystone on the projector…

I decided to completely reinstall that sandbox software. After reinstall and re-calibrate. all is fine.

This brings up the real questions.

1. Does rerunning the calibration build upon that previous calibrations? or does it start from scratch?

2. Are there files that can be deleted that would reset the calibration / setup so that the software does not have to be installed from scratch?

[Oliver Kreylos]

The only calibration files used by the AR Sandbox are BoxLayout.txt and ProjectorMatrix.dat. You edit BoxLayout.txt manually when measuring base plane and box corners, and ProjectorMatrix.dat is written when CalibrateProjector exits. CalibrateProjector starts a new calibration from scratch every time you run it, meaning there is no extra step required to reset a previous calibration.

In general, you should do a full calibration (base plane, box corners, projector alignment) after moving the sandbox, even if you don’t partially disassemble/reassemble it.

If there is a discrepancy in calibration quality between the red crosshairs in CalibrateProjector and the SARndbox application itself, check that

1. both programs run with the exact same window size and position, ideally both full-screen (hit Win-F to toggle between window and full-screen mode).
2. you didn’t forget the -fpv command line parameter for SARndbox.

[RodgerHoll]

Thanks Oliver.

Not sure what the issue was, but a fresh install in a new directory fixed it. I have the old folder that has the issue archived.

I did check the windows were run in full screen, and that the -fpv switch was present.

My version of the sandbox travels to schools and events, and recently took a 300 mile trip to St Augustine Florida. The tower that holds the projector and sensor are removable and the tower comes apart into 2 pieces for easier transport and also so the box will fit through standard classroom doors.
By design, the tower will reassemble and reattach within a few mm each time.

I will typically check the calibration before disassembly and transport, then just do a sanity check after the box is reassembled and filled with sand. (my wife wont let me have sand in the box at home)
The calibration always seems to be spot on when I fire it up.
Next step USB buttons.. (still using keyboard)

Thanks for the program, it definitely attracts people of all ages when running.

Rodger

[mkaszuba]

RodgerHall, would you be willing to post some images or plans for your table setup?

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