Tuesday, November 16, 2010

What users want from a wireless video link for HMDs

Sensics surveyed 179 users to determine their needs and wants on a wireless video link for head-mounted displays. The results of the survey, already shared with its participants, will be published in a few weeks, but I wanted to share some of the insights from it.

As part of the survey, we asked respondents to indicate the importance of several wireless link attributes such as distance, latency or battery life. Each feature was given an importance score from 1 (completely unimportant) to 6 (very important). We then sorted the aggregate results by the average importance assigned to them by the users. Results were:

Importance of various attributes of wireless video links for HMDs
It seems that the highest priorities were assigned to these features that make the wireless link nearly transparent to the application: high refresh rate, low latency, closed-loop operation to include down link tracking and stereo operation. The combination of these features differentiate wireless video products designed for HMDs with those targeted towards in-home use primarily to extend the distance between the set top box and the HDTV. A 1/2 second video link latency, for instance, might be quite insignificant when watching a basketball game on TV, but is devastating to closed-loop virtual reality applications.

Another key difference between in-home HDMI extenders and professional HMD-driven wireless links is the transmission technology. In-home HDMI extenders typically use ultra-wide band or the new 60 GHz extremely high-frequency radio band. Both of these need line of sight between the wireless transmitter and the wireless receiver. However, imagine an HMD user wearing the receiver in a backpack and then turning around. The user's body can easily cut off the line of sight between transmitter and receiver. Thus, technologies such as Wireless N which are not sensitive to line of sight limitations are clearly preferable for wireless HMDs.

I believe that wireless video links will help unleash the true potential of the personal, portable HMD. The freedom of movement, multi-user interaction opportunities offered by wireless links are substantial and I'd expect many exciting applications to materialize in 2011.

Thursday, November 11, 2010

Fourth generation optics are here

Someone once said 'Science is like a horse, not a cow; feed it, don't worship it'. I read this to say that even if you have very good technology, don't rest on your laurels but rather keep investing to make it great.

For several years now, My company has been building virtual reality goggles based on a unique optical tiling technology which allows creating goggles that are lighter, have wider field of view and higher definition.

At the core, the problem to be solved and the tiling solution are both simple to explain. Users want panoramic field of view because once the peripheral vision is engaged when wearing goggles, the sense of realism, immersion, "being there" is greatly enhanced. At the same time, users want high resolution and high pixel density so that they can get lifelike images. With today's micro displays, it is difficult to do both. If you magnify a micro-display just a little bit, you get good pixel density but narrow field of view, or "tunnel vision". If you magnify a display too much, you can get good field of view but low pixel density. High magnification also brings concerns about total weight, image distortion, clarity at the edge of the image, and all kinds of things that goggle manufacturers worry about.

If you could somehow make micro-displays that physically overlap, you would be in good shape because you can create a really high-definition micro display from many lower-resolution ones. However, making displays physically overlap is practically impossible. Our technology makes the displays optically overlap, essentially by carefully putting small magnifying glasses in front of each display. If they are properly positioned and aligned, the result is a nearly seamless image of both high resolution and panoramic field of view.

After investing quite a lot, we have now made 'nearly seamless' even better. Our fourth-generation optics are even better now. We've improved image clarity at the edges. We've improved what's called the 'eye box' (larger eye box means that you can still see a good image even if your eyes are not at the optimal position relative to the goggles). We've even changed the material from which we make the lenses.

So, we are excited about these fourth-generation optics and people that have tried it on are also excited. If you are in the market for a professional set of goggles, make sure you stop by to see our progress.

Tuesday, November 2, 2010

Overweight HMDs are still heavy, regardless of how they are supported

When I was a kid, I was discussing with a friend how overweight people sometimes wear black because it makes them look thinner. "Yeah", he replied, "but such clothing still uses a lot of fabric, even if it's black fabric".

I feel the same way about some of the professional HMDs out there. 2 lbs (1 Kg) is still 2 lbs no matter how hard you work to distribute the weight on the head. It's still heavy.

Most of the weight in head-mounted displays is concentrated in the front. This is where the optics are, as well as the micro-displays, and some electronics. Using such front-heavy HMDs can cause neck strain and general discomfort. Some companies actually put a counter-weight on the back of the head to offset the front-loaded weight. Others experiment with sophisticated head mounts that are designed to more evenly-distribute the weight on the head. But even if not heavy immediately, wear a 2 lb HMD for 10 minutes and you won't forget that it's 2 lbs.

HMDs should simply go on a diet.

Users get this. We just returned from Europe where we'd have a chance to see potential customers try on different HMDs from different vendors. Often times, heavy products were discarded very quickly. "Just too heavy", we heard.

Would you put up with sunglasses that hurt your nose? How about a hat that became truly heavy after 30 minutes?

Big may be beautiful, and black fabric does not hurt either, but heavy on the head is just too much to take.