1

Topic: Automatic Calibration

I finally updated my Atlas3D to v1.26.  I'm having problems doing automatic calibration. 

I've only had the chessboard successfully detected a few times.  When I do manage to pass that hurdle, the resultant calibration dimensions are badly out of wack...laser distances greater than 100 inches.

The RaspberryPi is fully updated, and I'm using the 8mp camera.  I've tried different backgrounds; here's my current environment:

https://www.dropbox.com/s/4tjuh6xji8p746d/Calibration%201.JPG?dl=1

With this visual, the Atlas3D still cannot detect the chessboard.

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Re: Automatic Calibration

I thought the cross hairs should be centered. Is your camera mount bent?

Printing since 2009 and still love it!
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Re: Automatic Calibration

No, that's just placement of the calibration device on the turntable.

If I revert to v1.22 and manually align the lasers, everything works fine.

4 (edited by knowack 2018-01-12 01:24:14)

Re: Automatic Calibration

I don't know if this is relevant, but if I scan anything in single laser mode (L or R), the preview is blank, as well as the final result.  If I use both lasers, I end up with both L and R shells, but they're misaligned, due to lack of calibration.

I've tried to manually enter the numbers I used in V1.22, but the results are very poor.

I should mention that this is a full-version of the software, Rpi2, laser-cut acrylic case.

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Re: Automatic Calibration

I've found that a white background seems to work reliably for detecting the chessboard.  However, the laser calibration is off, because the camera is including the laser strike on the background.

...still working on it.

6 (edited by hairu526 2018-01-14 14:20:39)

Re: Automatic Calibration

knowack, can you post the settings for the preset named "Calibration"?  Also, if possible can you include the log messages that are printed during the calibration step along with the resultant calibration file that shows up alongside the scan files?

Thanks,
Uriah

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Re: Automatic Calibration

hairu526 wrote:

knowack, can you post the settings for the preset named "Calibration"?  Also, if possible can you include the log messages that are printed during the calibration step along with the resultant calibration file that shows up alongside the scan files?

Thanks,
Uriah

Uriah,

Sorry for the delay; I've been bouncing back-and-forth between software versions to see if I could figure this out myself.  I have reinstalled the 5MP camera, since it works with both versions, but I plan on going back to the 8MP camera once I get 1.26 working correctly.  On the image of FreeLSS 1.26 that I'm using, the RPi is fully updated, except that the Kernel version is 4.4.50.  I'm sure I'm doing something wrong, but cannot figure out what.

Here's a screengrab of the settings for the Calibration preset:
https://www.dropbox.com/s/9u607b1790xl9fx/Calibration%20Preset%20Settings.JPG?dl=1
To my recollection, I haven't changed them from 'factory settings'.


Here's the log of a calibration attempt with a white background (it cannot find the chessboard against a black background):

Calibrated the turntable and right laser and left laser successfully.
boardPlaneCentroid ==> (-0.0120425,-1.13339,-9.73539) in.
boardPlaneNormal ==> (-0.0245098,-0.0209776,0.999479).
63 front right laser points are within range.
94 front left laser points are within range.
boardPlaneCentroid Rotated ==> (-0.0339888,-0.840125,-10.8671) in.
boardPlaneNormal Rotated ==> (-0.0351296,-0.0277334,0.998998).
72 total right laser points are within range.
133 total left laser points are within range.

Table Center: (-0.05861,-2.936,-10.36) in.
Table Normal: (0.003372,0.9999,0.01348)
Right Laser Location: (12.44,0,0) in.
Right Laser Normal: (-0.6266,-0.01651,0.7791)
Left Laser Location: (-19.57,0,0) in.
Left Laser Normal: (0.4411,-0.2279,0.8681)

The white background for this calibration was about 4 inches behind the turntable, with resultant laser distances of 12 and -19 inches (if I'm reading the log correctly).  If I run the calibration repeatedly, without moving anything, I get laser positions of 7 & -3, 20 & -23... When I put the scanner in another location where the white background is about 10 inches behind, it will think the lasers' distances are over 100 inches.  It would seem that the Atlas3D is picking up the laser strike on the background.  I cannot seem to find a suitable background that will allow the Atlas3D to detect the chessboard, AND ignore the laser strike on the background.

Here's some images to show the hardware alignment; I don't know if they're helpful:

Here's the camera aligned to the turntable:
https://www.dropbox.com/s/yrk54cbv6mpfnwb/camera%20alignment%202.JPG?dl=1


Here are the lasers oriented on the center of the turntable (my background is not squared up, so the lasers look crooked in the vertical; they are not):
https://www.dropbox.com/s/w00slc73dwvrlu4/camera%20alignment%203.JPG?dl=1


Here's the calibration target, sitting over the center of the turntable...just demonstrating laser alignment in the vertical:
https://www.dropbox.com/s/kgmd94z26hc4uur/camera%20alignment%204.JPG?dl=1


I have a monitor and keyboard connected to the Atlas3D.  For actual calibration, I set the target approximately 1 inch in front of the turntable's center, per the instructions.  When trying to calibrate with the black background, the command line says, "Chessboard not found.  Done."  This is the error message I get through the browser interface:
https://www.dropbox.com/s/lccfv0gabdj0ddi/camera%20alignment%205.JPG?dl=1


The basic hardware alignment I've shown is what has previously given me great results.  As posted in other threads, I've been able to get good details scanning Matchbox cars, and was working to improve my results from scanning 15mm soldier figures. 

Any insight would be appreciated!

Thanks!

-Kevin

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Re: Automatic Calibration

Can you post the PLY file that the calibration generates.  Also, disable Noise Removal and set the Threshold Mode to Low.

- Uriah

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Re: Automatic Calibration

Uriah,

Here's the corresponding .ply file:

https://www.dropbox.com/s/ogc67jn6krfp3 … 0.ply?dl=1

I disabled noise removal and set the threshold to low.  I didn't move or change anything else.  Here's what I got for calibration info:

Calibrated the turntable and right laser and left laser successfully.
Table Center: (-0.06807,-2.937,-10.34) in.
Table Normal: (0.00426,0.9999,0.01188)
Right Laser Location: (314.6,0,0) in.
Right Laser Normal: (-0.03447,-0.02405,0.9991)
Left Laser Location: (-1.256,0,0) in.
Left Laser Normal: (0.7964,-0.562,0.2234)

-Kevin

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Re: Automatic Calibration

Looking at the PLY file, it seems like it's having trouble picking up the laser points, especially on the back side.  Can you try reducing the amount of direct lighting?

- Uriah

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Re: Automatic Calibration

Uriah,

That is definitely having an effect.  If I reduce the lighting to 58 lux, I get laser distances of approximately 7" and -8". At 47 lux, I get 5" and -6".  Obviously, this results in each laser's output being skewed and slanted when I scan an object.  If I manually calibrate the lasers to 5.25", I get closer, and the geometry is more upright.

I've tried both the original 5MP, and the 8MP cameras.  The only other thing I've done is the firmware update to allow the 8MP camera to operate.

Previously, my Atlas3D had been performing great.  I cannot imagine what I've done.  I was trying to upgrade so that I could better scan 15mm wargame figures; I should have just left well enough alone!

-Kevin

p.s. I just tried 29lux, and the distances were 7 and -8...it seems to just be jumping around.