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Bad scan ! Help


Pigm@lion613
Posts: 10
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(@pigmlion613)
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Joined: 1 month ago

Hy,

after some problem with electronics parts, I try now to scan a part.

I use 2 green line lasers, well calibrated (vertical, crossing in the center of the plate). The camera is well centered too.

Calibration takes place properly. I try to scan a simple cylinder.

The result is like nothing!

In the configuration file, I have a doubt about certain parameters:
"turnable": {
"Steps": 3200,
"Radius": 100,
"Height": 80,
"degree_per_step": {
"Low": 3.6,
"Medium": 1.8,
"High": 0.8
}

Can you help me ?

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Pigm@lion613
Posts: 10
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(@pigmlion613)
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leonnoel
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(@leonnoel)
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Now the fun and guessing begin.   I don't know exactly what height dimension does so haven't changed from the 155 given in the example provided in the default.config.json file.  Please check the calibration chart information as the one I have is 6 rows, 11 columns and 13 mm squares which I beleive is the standard one for the Ciclops. If used 10 columns as the example shows you can have problems.  Find the page on the Fabscan web that shows how the columns and rows are determined.  I advise using a simple cubic to test your adjustments and calibration.  If you can get the 0 and 1 ply files to have good alignment then try a more complex.

For instance:

A tapered scale I think reveals that a laser or lasers or camera center may not be truly vertical. 

Different sizes in the plan view probably indicate that one or both lasers does not indeed pass through the table center.

In this part of the process so much can be adjusted, I'm sure that I'm only a beginner myself.

I would do this initial study not scanning color (texture).  Bloom or reflection will mess up what the camera sees and when you adjust the best trace the color scan is not good.

Incident light gives problems. There's a reason for the cover and inside black paint suggestion for the Fabscan.  Do your scan in a dark room at night for the best conditions, also adjust the camera parameters-contrast, saturation, etc. for the finest detectable laser line.

Don't only read the information on the Fabscan website once but perhaps 2 o3 times and then refer back often because things will surely change.  I strongly suggest Mario's book "Das 3D-SCANNER PRAXIXBUCH" as a reference.  It does a very adequate job of explaining and giving procedures which I have found to be very helpful.

I'm busy responding to something else but will give information on how to make a screen with black cloth for an enclosure that may help with the Ciclops,, also the cubic I use for checking my set up.

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Pigm@lion613
(@pigmlion613)
Joined: 1 month ago

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Posts: 10

@leonnoel :thanks for this first response.

Currently, I used the calibration grid proposed on fabscanpi, with the right parameters in the configuration file. I use the cyclop in a closed box with a gray background.

I activated a single laser, and a full scan returns no trace and .... no error.

do you know what the "height" parameter in the "turnable" section is. is it the height of the turntable from the ground, or the height from the center of the camera.

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leonnoel
(@leonnoel)
Joined: 2 years ago

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Posts: 55

@pigmlion613 No I don't know what the height dimension is for.  To make sure the stepper driver is set for the proper microstepping an easy way is place a mark on the turntable run a scan function and if it turns 360 degrees it is correct.  I think the relation of camera to turntable would be determined mathematically from the calibration pattern location and distance to the camera lens. If one were able to take the time and skill high enough looking at the software code you could discover it .

You may notice that although fun and frustration are spelled differently, they sometimes are closely related.

 

 

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leonnoel
(@leonnoel)
Joined: 2 years ago

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Posts: 55

Another thought, If I understand your info when you tried one laser you did not get a trace, if so, how do you know the laser even triggered for each or any position?

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Pigm@lion613
Posts: 10
Topic starter
(@pigmlion613)
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Joined: 1 month ago

Hy,

some news about my problems !

I made a closed box with a black interior around my cycle. The result is much better (scan_hibou.PNG).

But I still have some problems !

How to avoid having the lower trace, at the level of the turntable ?

I understood that the parameter turnable:height corresponded to the max height of the scan.

But nothing for the minimum height ?

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