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Help wanted with 3D design of calibration tool.  

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mario
Posts: 443
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(@mario)
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Joined: 2 years ago

Hi all, 

i need some help. I am working on calibration improvements to reach better calibration results. We need to run parts of the calibration process with different positions/angles of the calibration sheet. I am already working on the software part and i am using modeling clay to hold the sheet in different positions. That works for me, but i don't think that is the best solution for all of us.

The new calibration routine will work semi-automated. The whole process will be guided. I think the first version needs some additional calibration sheet positions. A good starting point will be a tilted sheet ( -+30 degree). 

I am looking for a nifty mount design to bring the calibration sheet in different positions. Here is a hand drawn sketch which will (hopefully) illustrate what i want to reach.

IMG 20200220 120037

The best solution would be a "one part" solution, something plugged together or maybe using magnets to hold it in position. I am completely open for your suggestions. Feel free to post your designs, thoughts or whatever might help.

Edit: 

A further improvement in a later iteration would be to rotate the sheet. 

IMG 20200220 124441

 

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archeotron
Posts: 17
(@archeotron)
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Joined: 6 months ago

Hello Mario, thanks for your Help 🙂
I`m testing the Hardware-Configuration of CebScan, because they use an up- and downlifting Cam, where you have an similar effekt of different Angles. I think you should also use an up- and downlifting Cam-Mount, which also can rotate it´s angle?!?
I´am only experienced in making large 3D-Models of landscapes using SFM-Software like Agisoft, with this Scanner I will made some Replicas of archeology Objekts i will use in Museum-Pedagogy, so i will need to reach a very good quality with the Scan.

Greets from Hesse

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archeotron
Posts: 17
(@archeotron)
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Joined: 6 months ago

Use an Mini-Gimbal for Pan and Tilt, like this:

https://www.amazon.de/non-brand-Schwarzer-Kunststoff-Servokamera-Plattform-Schwarz-Paket-B/dp/B07YDZKZNP/ref=sr_1_26?__mk_de_DE=%C3%85M%C3%85%C5%BD%C3%95%C3%91&keywords=pan+tilt+mount&qid=1582205260&sr=8-26
I think you got more Problems with the Object to scan, when you rotate this.

 

Have you already considered to use an real Laser-Scanner?
For example with an Lidar-Light Sensor...

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mario
Posts: 443
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(@mario)
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Joined: 2 years ago
Posted by: @archeotron

I think you got more Problems with the Object to scan, when you rotate this.

Oh maybe my description is not precise enough. I don't want to rotate/tilt the object during the scan. I want to improve the calibration process to reach a better calculation to fix the camera distortion etc. ( https://docs.opencv.org/2.4/modules/calib3d/doc/camera_calibration_and_3d_reconstruction.html )

And to reach this i need to spit the current calibration process into multiple steps where the user needs to realign the calibration tool on the turntable. I am just looking for a clever design for the printed calibration sheet foot in a way that you can place the sheet in multiple angles. Maybe this can be archived by adding some bevels to the current used STL design. 

Posted by: @archeotron

Use an Mini-Gimbal for Pan and Tilt, like this:

Not that bad but i would prefer a solution without additional electronics.

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EMW
Posts: 25
 EMW
(@emw)
Eminent Member
Joined: 7 months ago

I quickly sketched something out. I hope I understand the issue correctly.

Position 5
Position 4
Position 3
Position 2
Position 1

Is not true to scale for now.
The dimensions would have to be adjusted.

Just as an idea
Best wishes

Torsten

 

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