See The Science Behind VR Display Design, And What Makes A Problem Important

August 3, 2020 by Donald Papp 28 Comments

VR headsets are more and more common, but they aren’t perfect devices. That meant [Douglas Lanman] had a choice of problems to address when he joined Facebook Reality Labs several years ago. Right from the start, he perceived an issue no one seemed to be working on: the fact that the closer an object in VR is to one’s face, the less “real” it seems. There are several reasons for this, but the general way it presents is that the closer a virtual object is to the viewer, the more blurred and out of focus it appears to be. [Douglas] talks all about it and related issues in a great presentation from earlier this year (YouTube video) at the Electronic Imaging Symposium that sums up the state of the art for VR display technology while giving a peek at the kind of hard scientific work that goes into identifying and solving new problems.

[Douglas] chose to address seemingly-minor aspects of how the human eye and brain perceive objects and infer depth, and did so for two reasons: one was that no good solutions existed for it, and the other was that it was important because these cues play a large role in close-range VR interactions. Things within touching or throwing distance are a sweet spot for interactive VR content, and the state of the art wasn’t really delivering what human eyes and brain were expecting to see. This led to years of work on designing and testing varifocal and multi-focal displays which, among other things, were capable of presenting images in a variety of realistic focal planes instead of a single flat one. Not only that, but since the human eye expects things that are not in the correct focal plane to appear blurred (which is itself a depth cue), simulating that accurately was part of things, too.

The entire talk is packed full of interesting details and prototypes. If you have any interest in VR imaging and headset design and have a spare hour, watch it in the video embedded below.

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Torturing An Instrumented Dive Watch, For Science

July 18, 2019 by Dan Maloney 24 Comments

The Internet is a wild and wooly place where people can spout off about anything with impunity. If you sound like you know what you’re talking about and throw around a few bits of the appropriate jargon, chances are good that somebody out there will believe whatever you’re selling.

Case in point: those that purport that watches rated for 300-meter dives will leak if you wiggle them around too much in the shower. Seems preposterous, but rather than just dismiss the claim, [Kristopher Marciniak] chose to disprove it with a tiny wireless pressure sensor stuffed into a dive watch case. The idea occurred to him when his gaze fell across an ESP-01 module next to a watch on his bench. Figuring the two needed to get together, he ordered a BMP280 pressure sensor board, tiny enough itself to fit anywhere. Teamed up with a small LiPo pack, everything was stuffed into an Invicta dive watch case. A little code was added to log the temperature and pressure and transmit the results over WiFi, and [Kristopher] was off to torture test his setup.

The first interesting result is how exquisitely sensitive the sensor is, and how much a small change in temperature can affect the pressure inside the case. The watch took a simulated dive to 70 meters in a pressure vessel, which only increased the internal pressure marginally, and took a skin-flaying shower with a 2300-PSI (16 MPa) pressure washer, also with minimal impact. The video below shows the results, but the take-home message is that a dive watch that leaks in the shower isn’t much of a dive watch.

Hats off to [Kristopher] for doing the work here. We always love citizen science efforts such as this, whether it’s hardware-free radio astronomy or sampling whale snot with a drone.

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Making A Bathymetric Book By Hand And Searching For An Easier Way

October 3, 2013 by Mike Szczys 15 Comments

We first saw this Bathymetric Book at our local hackerspace, Sector67, quite some time ago. [Caroline Rose] gave a seven minute presentation on the project as part of the monthly meeting which is open to the public. You can get a pretty good feel for the book that includes a to-scale depth representation of Crater Lake in the introductory post which she recently published. Each page makes up one topographical ring of the lake. Put them all together and you’ve got a really amazing way to explore the watery depths of the deepest lake in the United States.

The book you see above is hand made. She downloaded the depth data from the US Geological Survey, then put it through some processing in order to print one elevation level on each page. That’s when the work really began. She cut out every page by hand! The four-plus hour task was grueling. And just for a bit of added punishment she even made a second book. But at Tuesday night’s follow-up presentation she said never again.

[Caroline] developed a much faster and still accurate technique for producing the bound-book depth maps. She is using a laser cutter and a different binding technique. By using folded packets of paper, rather than individual pages, she is able to cut out three double-sheets at once — including holes for the binding thread and the outline of the finished pages themselves. This cuts the process down to about four minutes of laser cutter time.

For now you’ll have to settle for a time-lapse video of the hand-cutting process (embedded below). But we hope to post an update when she makes more information about the laser-cut version available.

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