Code resource

Here is a good resource for code for optimization problems in vision that show up a lot while making small sensors. Thanks to AJ for the link.

Graphene sensors

The Economist has a fascinating article about how researchers are using graphene, interspersed with tiny dots of lead sulphide, to absorb light and produce electrons that can be converted into a signal. The cool thing about these proposed photodetectors is that they might be flexible, allowing many applications. They possibly could also be made very small and might even allow the creation of a "light transistor". 

Stereoscopy on small devices

Thanks to EJ for sending me this article. Its a nice overview of the challenges faced when showing stereoscopic content meant for one screen on another, different display. The most interesting section, for me, was about 3D content on mobile phones. The author points out two interesting things: (1) Given the size of the screen, 3D movies and games for portable devices are *usually* easy on the eyes (the disparity-focus headache factor is low). However: (2) The "miniaturization" effect (where objects appear toy-like) is very strong. This means that (outside of "cute'" games) most scenes will appear (to paraphrase the author) as if strangely in a small box. I think the field is wide open for formats and representations that will allow good viewing of 3D content on small devices.

The 21st century's foundry

I've been busy with a lot of moving stuff, so that is why there has been a lack of posts. Hopefully I'll write more in the next few months.

I've been really enjoying (and nodding while reading) the Economist's special report on personal manufacturing as the next industrial revolution.

Flashing signs

The Economist has a neat article about how Casio is getting smartphones to talk to each other using flickers in their displays. Pulses of light are the way DMD and MicroVision projectors send out light, so you might be able to extend this idea to portable projectors.

Eye dust in the sky

The Economist has an article about civilian micro air vehicles and how society might react to them. Two interesting technical things I learned from the article was that (1) AeroVironment makes most of the US's micro air vehicles and (2) A company called SARA makes acoustic sensors for micro-air vehicles that block out wind noise and can detect other planes and do collision avoidance.

I want to talk about the article's focus on the societal impact of tiny visual sensors. The advent of such small camera-enabled robots will be the first of many technologies, with serious privacy concerns, that will probably come out in the next 10-20 years. For now, the available micro air vehicles are relatively large (laptop size or smaller). But smart dust and other futuristic visions are closer than you think. Sure, these ideas have been thrown around for the past two decades. But as we get close to the point when science fiction becomes commercial product, the human impact will be substantial and we must prepare for it. Millions of costless micro-cameras will envelope our lives in a 24 hour obtrusive sensor blanket. Combined with face detection, these micro-sensors will be able to identify individuals over a large area quite quickly; frankly, this would mean that end of privacy as we know it. Of course there will be air filters and particle blockers (for some predictions, see the Diamond Age), but the relentlessness of manufacturing processes and the possibility that these small devices will exhibit self-replication would probably overwhelm any stop-gap measure. I'm not sure I have any comments on how to make this situation better, because I'm pretty sure its inevitable.

Last 2011 posts: RIM and Solar optics

Its been a while since I've posted, but here are a couple of interesting things that caught my eye recently.

First, RIM: There are reports of a takeover for Research in Motion (RIM), the makers of BlackBerry. RIM has gotten hammered by the iPhone in the upmarket scene and by the Android tsunami in the mid and low cost sections of the market. In fact, the key (no pun intended) advantage of BlackBerry phones remain security (each device gets its own 32 bit pin) and an email server network that takes it own initiative, pushing email onto your device from, say, your employer's servers. These security characteristics are loved by those in finance and government, all over the world, and so RIM seems to have a niche market for now. Especially since these customer groups are quite loyal: look at how the finance world swears by the Bloomberg terminals. But further growth in RIM might be limited to just these markets and I think that's what shareholders might be unhappy about. Further drama in any possible takeover is due to the Canadian govt; according to this Nytimes article, which claims that Canada may not be open to a foreign takeover of what they consider an "important" company. Well I think, with state support, RIM could survive this lean period to fight another day. From my biased perspective as a supporter of camera-centric thinking, I think RIM should take advantage of its rep as a maker of tough, "phones for the Pro" and perhaps think about camera sensors that would be advantageous to law enforcement, firefighters and first responders: perhaps mobile IR and thermographic sensors on Blackberry phones?

Second, optics for Solar cells: We know that solar cells covert electromagnetic waves from the sun to electricity. But an important part of solar cells are the optics that make sure the maximum possible sunlight is captured by the cell. There are some cool companies out there that use ray tracing (geometric optics) to increase the length of the ray through the photo-sensitive part of the solar cell. The key here is to make the optics flexible and thin, so it can be "rolled out" (basically printed or fabricated) along with the solar cell. So the ideas that dominate solar optics are ones that exploit total internal reflection or rough surfaces. Designs from SolOptics and Morgan Solar follow this trend, and these links have cool explanatory diagrams.

You can also go beyond the optics that collect light, and think about modulating the incoming solar radiation into something that can be easily converted to electricity. The Economist has an article about a "lens" for a solar cell that is made of tiny pits in a sheet of tungsten. The pit size is such that heat from the sun is easily absorbed. But when this heat is re-radiated out from the tungsten sheet, it gets "lost" in the pits and reabsorbed into the sheet. Its a heat trap, that allows easy entry but difficult escape. So the tungsten sheet "trap" gets very hot, and a custom solar cell behind it is tuned so that the heat that does escape the "trap", is mostly converted to electricity.

Happy New Year!