Light Fields: Missing Ingredient For Immersive 3D Video Gets Improved

46 time-synchronized action cameras make up the guts of the capture device.

3D video content has a significant limitation, one that is not trivial to solve. Video captured by a camera — even one with high resolution and a very wide field of view — still records a scene as a flat plane, from a fixed point of view. The limitation this brings will be familiar to anyone who has watched a 3D video (or “360 video”) in VR and moved their head the wrong way. In these videos one is free to look around, but may not change the position of their head in the process. Put another way, pivoting one’s head to look up, down, left, or right is fine. Moving one’s head higher, lower, closer, further, or to the side? None of that works. Natural movements like trying to peek over an object, or moving slightly to the side for a better view simply do not work.

Light field video changes that. It is captured using a device like the one in the image above, and Google has a resource page giving an excellent overview of what light field video is, what it can look like, and how they are doing it. That link covers recent improvements to their camera apparatus as well as to video encoding and rendering, but serves as a great show-and-tell of what light fields are and what they can do.

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Open-Source Arm Puts Robotics Within Reach

In November 2017, we showed you [Chris Annin]’s open-source 6-DOF robot arm. Since then he’s been improving the arm and making it more accessible for anyone who doesn’t get to play with industrial robots all day at work. The biggest improvement is that AR2 had a closed-loop control system, and AR3 is open-loop. If something bumps the arm or it crashes, the bot will recover its previous position automatically. It also auto-calibrates itself using limit switches.

AR3 is designed to be milled from aluminium or entirely 3D printed. The motors and encoders are controlled with a Teensy 3.5, while an Arduino Mega handles I/O, the grippers, and the servos. In the demo video after the break, [Chris] shows off AR3’s impressive control after a brief robotic ballet in which two AR3s move in hypnotizing unison.

[Chris] set up a site with the code, his control software, and all the STL files. He also has tutorial videos for programming and calibrating, and wrote an extremely detailed assembly manual. Between the site and the community already in place from AR2, anyone with enough time, money and determination could probably build one. Check out [Chris]’ playlist of AR2 builds — people are using them for photography, welding, and serving ice cream. Did you build an AR2? The good news is that AR3 is completely backward-compatible.

The AR3’s grippers work well, as you’ll see in the video. If you need a softer touch, try emulating an octopus tentacle.

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