3D scan - LBF/ZAB21 Software equipment in dental …...3D scanning process of analyzing a real-world...

3D scanLBF/ZAB21 Software equipment in dental office

Mgr. Marketa Trneckova, Ph.D.www.marketa-trneckova.cz

Palacky University, Olomouc

www.marketa-trneckova.cz

Creating 3D model

virtual computer model — created in graphical 3D software (eg. CAD)

data format - STL

own design - CAD, TinkerCad (https://www.tinkercad.com/), 3D Builder,FreeCAD, . . .downloadable models:

https://www.thingiverse.com/

https://www.myminifactory.com/

https://www.youmagine.com/

http://www.3dshook.com/

use of 3D scanner

Mgr. Marketa Trneckova, Ph.D. (UPOL) 3D scan 1 / 15

https://www.tinkercad.com/

https://www.thingiverse.com/

https://www.myminifactory.com/

https://www.youmagine.com/

http://www.3dshook.com/

3D scanning

process of analyzing a real-world object or environment to collect data on its shape andpossibly its appearance (e.g. colour)

collected data can then be used to construct digital 3D models

3D scanner can be based on many different technologies:

optical technology - difficulties with shiny, reflective or transparent objectscomputed tomography scanning

wide variety of applications:

entertainment industry - production of movies and video games, including virtual realityaugmented reality, motion capture, gesture recognitionindustrial designorthotics and prostheticsreverse engineering and prototyping, quality control/inspectiondigitization of cultural artifacts


purpose of a 3D scanner

to create a 3D model

3D model: consists of point cloud of geometric samples on the surface of the subject

these points can then be used to extrapolate the shape of the subject (reconstruction)

we can collect information about color for each point

3D scanners - can only collect information about surfaces that are not obscured

distance information about surfaces within its field of view - describes the distance to asurface at each point in the picture

for most situations, a single scan will not produce a complete model of the subject

multiple scans from many different directions are usually required to obtain informationabout all sides of the subject

registration - scans have to be brought into a commonreference system and then merged to create a complete 3Dmodel

3D scanning pipeline - whole process, going from thesingle range map to the whole model


Technology

contact

non-contactactivepassive


Contact scanners

probe the subject through physical touch,while the object is in contact with orresting on a precision flat surface plate

CMM (coordinate measuring machine)

advantages: very precise

disadvantages: act of scanning theobject might modify or damage it,relatively slow


Non-contact active

emit some kind of radiation or light and detect itsreflection or radiation passing through object inorder to probe an object or environment

possible types of emissions used include light,ultrasound or x-ray

3D laser scanners (Time-of-flight, Triangulation,Conoscopic holography, . . . ) - suitable formeasuring large objects, less accurate

Structured-light 3D scanner - project a pattern oflight on the subject and look at the deformation ofthe pattern on the subject

Volumetric techniques - CT, MRI - generates athree-dimensional image of the inside of an objectfrom a large series of two-dimensional images


Non-contact passive

do not emit any kind of radiationthemselves, rely on detecting reflectedambient radiation (visible light)

very cheap

Stereoscopic systems - 2 video cameras,slightly apart, looking at the same scene.By analysing the differences between theimages, it is possible to determine thedistance at each point in the images

Photometric systems - 1 camera -multiple images under varying lightingconditions

Silhouette techniques - outlines createdfrom a sequence of photographs around athree-dimensional object against a wellcontrasted background


EINSCAN-SE

scan mode:

automaticfixed (without turntable)

wide range

allows color scans

scan duration: 8s

duration of 360◦ in automaticscan mode: 2min

plug&play installation

max. scan volume: 200mm

min. scan volume: 30mm

resolution: 1.3 Mpx

resolution of 3D scanner: 0.1mm

data formats: STL, OBJ, ASC,PLY


EINSCAN-SE

Scanner head

Turntable

Scanner stand

Scanner bracket

Calibration board

Calibration board holder


EINSCAN-SE — limitation

you cannot scan objects:

smaller than 30 mm x 30 mm x 30 mmlarger than 250 mm x 250 mm x 250 mmheavier than 5 kg

difficult to scan:

transparent objectsshiny materialsdark objectsfurry objects

do not scan:

moving objectshollow objects


EINSCAN-SE software

https://www.einscan.com/support


https://www.einscan.com/support

EINSCAN-SE - calibration

should calibrate the scanner in the initial set-up, or if youmove the scanner or turntable

when you find the scanned quality is not as good as initialset-up

calibration is needed when alignment mistake or failurefrequently appear during the scanning

require calibration board

calibration board is scanned in 3 directions

Steps:

insert calibration board onto the board holderplace the calibration board on the center of the turntablefacing the scannerrun the calibration


EINSCAN-SE - scan process1 Build project2 Choose texture scan (if color texture is needed or not)

Texture scan - little longer time, and white balance test should be done before scanning3 Place object4 Adjust Brightness - choose the brightness setting according to your object surface

condition

too much red appears on the object shown in the window means over bright


EINSCAN-SE - scan process

5 Set up (number of turns) and start scan

6 Edit scan - remove redundant parts

7 Scan in more directions- data will be aligned to the last scanned data automatically

8 If automatic alignment fail during scanning, you can use manual alignment

9 Mesh - Watertight or Unwatertight model

10 Save (.stl, .obj, .ply)


Task

Try to scan several objects not suited for scanning (shiny, transparent, . . . )

Scan suitable object

Save it into STL

Modify model with ThinkerCAD


3D scan - LBF/ZAB21 Software equipment in dental …...3D scanning process of analyzing a real-world...

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