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Raspberry pi based scanner.

Posted by GRAYWOLF 
Raspberry pi based scanner.
October 16, 2016 09:41PM
I have a few question concerning raspberry pi based 3d scanners and I'm not sure where to ask.

Q1 - How far from the camera can the turntable be?
Q2 - Does the Pi Zero run the software?
Q3 - Does the new camera result in better scans?
Q4 - Does the new Pi3 result in better scans?
Re: Raspberry pi based scanner.
October 17, 2016 12:07AM
What raspberry pi based 3d scanners are there? You ask like there is loads of scanners out there. I am still looking for one to buy.

Edited 1 time(s). Last edit at 10/17/2016 12:08AM by audiobull.
Re: Raspberry pi based scanner.
November 25, 2016 12:13PM
Quote
audiobull
I am still looking for one to buy.

I believe these are DIY questions, not ready made.

I'm no engineer but I'll take a stab as no one else has, fwiw.

For reference, this was the one I was looking at for simple project. [www.instructables.com]

Q1) Idk, but I'd guess it would be a function of the Webcam (it's ability to sense tiny deviations) and distance needed to achieve required angles. From the instructable: "The only constraint is to have the camera seeing the whole table."

Q2) PiZero is effectively a ?Pi2? ... Just without all the extra hardware, so yes, the OS and programs will be stored on the MicroSD card. In analogy to a 3d printer (i.e. Prusa) the Nano is the Mega, b/c less motor requirements needed allow smaller microcontroller. TL;DR: Nano = uC, RpiZero = PC, StepperMotorController = RAMPS board ... Connecting to the PiZero is the challenge. As it went with Micro everything for hardware (USB, HDMI, SDcard). So many people use a 'headless' setup (ssh through: wifi or usb)

Q3) I would think the higher the resolution the camera would affect the resolution of the scanned image, as the camera is effectively the 'scanner', but maybe a ?relationship between quality/size of laser vs dpi of 'scanner'? i.e. If laser takes up 8 pixels it's coordinate reading may not be as precise? However we could be talking extremes here, I guess you would be looking to relate pixels to actual coordinate distance on scanned image, if trying to compute tolerances? Or how many pixels the diameter of the laser is in the scanned image?

Q4) The quality of the 'scan' will be somewhat independent of the hardware, imo. As long as the hardware can properly run the programs (scan at desired DPI/MegaPixel), I think the only differences could be related to processing time, ect. However, I would think for 'compiling' data(scans) you would want to run on a normal PC, for the extra CPU/RAM capacity...May want extra capacity in your SDcard too, depending if the software is just archiving scans or doing to difference computations in the process.

Hopefully someone with experience can comment. I sometimes can't help myself with Theorycraft winking smiley

EDIT: After looking at the instructable more, I see there is no RPi in this one, he just hooks Nano to PC. I guess you 'could' run with RPi doing the 'nano stuff' but personally, for $5, I'd use the nano for the motor stuff (i/o pins to motor controller, ect), and just use the RPi as the PC. You have to be way more careful with overloading a RPi than a uC.

Edited 4 time(s). Last edit at 11/25/2016 12:56PM by VonRansak.
Re: Raspberry pi based scanner.
December 23, 2016 03:18PM
Currently I am building a Fabscan Pi, which is definitely an Open Source pi based 3D scanner.

The original design has gone through several stages from an Arduino based, then hybrid variants.

The latest is Pi only and looks GREAT. And potentially AWESOMALLY UPGRADABLE.

The case design is a set of laser cut files, so if you have have ever wanted to treat yourself to a "BETTER THAN PLYWOOD" material you can!

Hat for the Pi with a stepper controller required, as is a Pi camera or other device. An illumination ring complete with a mounting for a Pi Hat is an option, but apparently the Adafruit illuminator is ring good too. Not sure about that, the Pi illuminator is preferred I think if you are using a Pi camera.

Full kit (but no manual, just an RTFM sticker) is available from Watterot for $185 Euro, everything bar tools and glue. And maybe an SD card for the Pi, although apparently Watterot flash the Pis in the kits. You can also source your own bits and pieces, Watterot do sell the parts seperately.

[www.watterott.com]

Original thesis;-

[hci.rwth-aachen.de]

Software (yummy).

[mariolukas.github.io]

You could hack the design onto a much bigger turntable. Although you would have to compensate for drop in resolution. winking smiley

You end up with a cloud based scanner that you dowload .ply mesh objects from. No screen, keyboard or mouse required to use, just a web browser over Wifi or Network cable.

About 3 minutes for a scan with a Model 3B Pi. A commercial scanner could probably do that in 30-40 seconds, but would not be running Python scripts to get scan results.

The basic kit only has one laser and servo, but you can fit a second laser and servo for more accurate results. That does mean fitting a bigger power supply than the standard 2Amps at 5V,

Edited 4 time(s). Last edit at 12/23/2016 03:36PM by DragonFire.
Re: Raspberry pi based scanner.
December 24, 2016 05:04AM
I have just built a Ciclop scanner which uses an Arduino Uno and a Zum Scan board, but there are versions which use a Raspberry Pi.
The usual camera used is a Logitech c270 camera but others can also be used.
The Horus scanning software is a free download.
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