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3D reconstruction

The third dimension at a glance

by Francisco Javier Delgado del Hoyo

Stereopsis

  1. Two images of the scene are taken by the eyes at the same time
  2. Disparity and parallax yield the perception of the depth
  3. The visual field is constrained by overlapping areas
The human brain fuses two stereoscopic images to perceive the depth of the surrounding objects.3dstreaming.com

What's the point?

We live in a three-dimensional world ...

The brain can be tricked

3D films exploit stereopsis so you can rebuild depth and distances inside your brain

How polarized 3D glasses works?3dglasses.cc

Virtual Reality

Head Mounted Displays show a slightly displaced image for each eye

Screenshot of a panoramic image visualized on a Head Mounted DisplayGoogle Cardboard

A commercial explosion

Samsung Gear VR (2014)
Oculus Rift (2012)
Google Cardboard DIY
Google Cardboard (2012)

How can machines compute depth?

Can robots perceive the third dimension?Geek Magazine

How can machines see?

Computer Vision

Digital cameras

Image perception capabilities of the human eye are simulated by digital cameras, which are becoming progressively cheaper, smaller and more accurate.

Did you know that if the human eye were a digital camera it would have 576 Mpx?

Cameras are available everywhere

Handheld laser scanner
Microsoft Kinect One
Stereo camera rigs
Drone with on-board camera

Your imagination is the limit!

3D scanning rig composed of 80 cameras.

However, only the hardware isn't enough ...

... there are several ways of computing depth taking into account the number of views

Binocular Stereo

If the positions of the lenses are fixed and well-known, then depth is inversely proportional to the disparity between each pair of pixels.

A point cloud generated from a pair of images of an Aloe Vera plant.OpenCV Stereo Matching

Multiple View Stereo

Workflow of 3D reconstruction from multiple uncalibrated images.Yasutaka Furukawa

But, could we perform real-time 3D reconstruction with only one lens?

My research

Monocular Simultaneous Localization and Mapping

In summary

  1. stereopsis helps us to perceive depth
  2. digital cameras are the "eyes" of the robots
  3. algorithms to retrieve depth heavily rely on the available hardware

Thanks for your attention!

Questions?

Replay this presentation at http://fradelg.mobivap.es/slam

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