3D Printer Meetup - 2NAC 7/24/14
• Current: Roboticist, MIT Lincoln Laboratory– Focus: 3D perception
• Past: Carnegie Mellon Robotics Institute– Focus: Planning under uncertainty
• Future: Heuristic Labs– Focus: 3D sensors
• Origin (fun fact): Alaska– Focus: None
Who am I?
“Nick Armstrong-Crews” - http://www.linkedin.com/in/nickarmstrongcrews
3D Printer Meetup - 3NAC 7/24/14
• Theme: CAD is hard; a barrier to 3D printing revolution– Imagination ---(CAD)---> digital model ---(3D printing)---> Reality– Harder than 2D (i.e., photo-realistic painting/sketching)
• Aside: 2D sensing sucks– Loss of depth information; loss of absolute dimensions– Simply insufficient to aid creation in a 3D world
• Solution: 3D sensing to the rescue!
• Caveat: 3D sensing can be noisy– But fixing up a 3D model is easier than creating!
Why 3D Sensing is Important
“This stuff is really hard. It's hard to learn, hard to use, and mistakes have real consequences. This [is true] of any CAD or modeling software.”
“CAD is Hard” - http://sliptonic.com/cad-is-hard/
3D Printer Meetup - 4NAC 7/24/14
The “Matter Remixer”
“Reality Remixing” - http://bit.ly/MatterRemixerKS
3D Printer Meetup - 5NAC 7/24/14
• Principles:– Time-of-flight: ,– Stereo parallax (triangulation): ,– Multi-view stitching (mapping, SLAM): (complicated)
• Implementations:– Passive stereo vision: like humans! two cams, rigid mount, sparse and not robust
and reliant on background texture
– Structure-from-motion: monocular, move camera over time
– LIDAR: raster scanning/spinning point detector
– Active stereo vision: create own perfectly structured light
3D Sensing Techniques
𝒅=𝒄𝒕𝟐
“Time-of-Flight Camera – An Introduction” - http://www.ti.com/lit/wp/sloa190b/sloa190b.pdf“Triangulation (computer vision)” - http://en.wikipedia.org/wiki/Triangulation_(computer_vision) “Projected Texture Stereo” - http://www.willowgarage.com/sites/default/files/ptext.pdf“Serveo w/ Planar LIDAR” - http://april.eecs.umich.edu/magic/about/
𝒅=𝒃𝒇∆𝒖
𝒃
𝜺𝒅 𝒅𝟐
𝜺𝒅 𝜺𝒕
3D Printer Meetup - 6NAC 7/24/14
Available Hardware Comparison
“LazeeEye: Turn your Smartphone into a 3D Camera” - http://kck.st/1gVCcrB
Principle Cost Resolution Mobile? Outdoors? Caveats
DepthSense ToF $299 640x480, +-3cm at 3m
kinda
Kinect(Xbox One)
ToF $399 520x240 kinda Windoze 8.1
Xtion / Kinect (original)
ToF $99-$150 640x480, +-2cm at 2m
PrimeSense inside
Cubify Sense Active Stereo
$399 640x480, +-2cm at 2m
PrimeSense inside
Occipital Structure
Active Stereo
$379 640x480, +-2cm at 2m
Yes(tablet)
Apple-only, PrimeSense
inside
Google Project Tango
Active Stereo
$1024 640x480, +-2cm at 2m
Yes(tablet/phone)
Limited release, pre-production
HLLazeeEye
Active Stereo
$75 Yes(phone)
Yes Pre-production
3D Printer Meetup - 7NAC 7/24/14
• Structure-from-Motion– AutoDesk 123D Catch - http://www.123dapp.com/catch – VisualSfM - http://ccwu.me/vsfm – Seene iPhone App - http://seene.co
• DIY– DIY Structured Light - http://mesh.brown.edu/byo3d/source.html – DIY Stereo Cams - http://
wiki.ros.org/camera_calibration/Tutorials/StereoCalibration (any cam pair, but recommend PS4 Eye or dual PS3 Eyes)
• Computer-assisted 3D Editing– Meshlab - http://meshlab.sourceforge.net – AutoDesk Meshmixer - http://meshmixer.com
Useful Resources