Sunday, December 2, 2007

Are you blind when using a head-mounted display?

I received a letter from the Maryland Motor Vehicle Administration that my driver's license needs to be renewed. This happens once every five years, and also is a nice reminder that my birthday is coming up.

Checking the MVA site to determine the closest location and list of required documents, I also saw the vision test requirements. Take a look at these requirements from the Web site:

To qualify for an unrestricted driver’s license, the State of Maryland requires drivers to have:
  • Binocular vision
  • Visual acuity (Snellen) of at least 20/40 in each eye
  • A continuous field of vision of at least 140 degrees

Restricted licenses may be issued to persons having:

  • Visual acuity of at least 20/70 in one or both eyes
  • A continuous field of vision of at least 110 degrees, with at least 35 degrees lateral to the midline of each side
A related definition of visual performance is the 1934 American Medical Association of blindness: "Central visual acuity of 20/200 or less in the better eye with corrective glasses or central visual acuity of more than 20/200 if there is a visual field defect in which the peripheral field is contracted to such an extent that the widest diameter of the visual field subtends an angular distance no greater than 20 degrees in the better eye."

Those definitions made me wonder: how close you are to being blind when you wear an HMD?

With most head-mounted displays, field of view is limited: typically 30 to 50 degrees horizontal (not far from the definition of legal blindness). Only very few products, such as those from my company offer wide field of view that would be enough to meet the driving requirements.

Similarly, many HMDs have limited resolution that would constitute legal blindness. While resolution is sometimes reported as total number of pixels (e.g. 800x600 pixels/eye), an important measure is the number of pixels per degree, or pixel density. I saw a product recently that claimed wide field of view but offered less than 10 pixels/degree. This is about 20/125 visual acuity according to Snellen notation (6/38 metric). For more technical information, see this excellent Visual Acuity web page at the University of Utah.

I'm not suggesting in any way that anyone should attempt to drive with an HMD. It does seem, however, that most HMDs still have a long way to go in enhancing field of view and resolution/pixel density before they become truly usable.

Friday, November 9, 2007

How important is VR in education?

I had the pleasure of participating in a panel discussion in the "Simulation and the learners of tomorrow" conference organized by the Center for Technology (CTE) in Education at Johns Hopkins University. The conference was attended by teachers, educational administrators, technologists, government and state officials and more.

CTE is one of our first customer, focusing their research in science and math education on the middle-school level. It was fun spending the day with educators to discuss the future of education and how simulations, virtual reality and other advanced technologies can take a part in educating our kids.

I picked up on several interesting questions :
  • How effective will VR be in education? There is no question "VR" is super cool - just ask the dozens of kids that tried Sensics head-mounted displays, but does this coolness translate into more effective learning and retention?
  • What is the preferred display device for VR learning? Is it a large projection display which engages all the class at the same time, or is it head-mounted displays that allow different students to learn immersively at their own pace with little or no distraction from other classmates?
  • Who will pay for VR? Will the school system do it using technology budgets? will this become an after-school enrichment program?
  • How will VR get into the classroom? Will it be a top-down decision from the administrators, or a grass-roots action where rebel teachers that are excited about the VR experience they had elsewhere (home, arcade, science museum) experiment with it in class?
  • If VR is effective, is this effectiveness the result of the newness factor (students are glued to the device because it is new and they have not experienced 3D immersion before), or is it really more effective than standard interactive software on a desktop?
  • What material will be most effective for VR? Is it math and science (e.g. "fantastic voyage inside the body"), history (where VR can take you to other civilizations)? something else?
  • How quickly will VR in education become mainstream?
CTE plans to have a follow-up conference next year, and I hope to be able to report progress from there as well.


Thursday, October 4, 2007

Fulfilling your childhood dreams

Make sure you view Randy Pausch's lecture "fulfilling your childhood dreams" about life, VR and everything in-between.

Monday, August 27, 2007

Motion Capture at Siggraph - Linking Real Motion to Virtual Worlds

There were many motion capture demonstrations at the recent Siggraph show. Applications for motion capture include animated films, special-effects sequences, video games (e.g. capturing the throwing motion of a quarterback), academic studies in motion and more.

Most demonstrations involved models wearing body suits and moving in a large area with a uniform background. Real-time systems captured the movement and displayed it on computer screens.

A particularly exciting motion capture demonstration was staged at the WorldViz booth. Data from the motion capture system was fed into Vizard, the VR software platform from WorldViz and then used to drive the on-screen movement of an avatar. The avatar operated in a virtual world and interacted with it. In the particular Siggraph demo, the avatar was initially surrounded by many wooden boxes. By moving around, the model was able to rearrange the wooden boxes so as to show a compelling interaction between the virtual and real worlds. Moreover, the human model had two viewing options: view the complete scene on a projection screen (which drew a large crowd throughout the show), or wear an HMD (see image) and get a first-person experience as if being there. Incidentally, the software could also be configured to show the scene from another person's viewpoint, thus providing an "out of body" experience to the model who was able to view her own movements driving the avatar from a different viewpoint.

Wednesday, August 1, 2007

Are Existing Head-Mounted Displays ‘Good Enough’?

During the spring of 2007, Sensics, my company, conducted a broad worldwide survey amongst academic, commercial, and government users of virtual reality systems. The survey was designed to understand user perceptions of current head-mounted display (HMD)
technology as well as desired performance characteristics of what was termed a 'good enough'

Key survey findings include:

1. Most existing HMDs are not ‘good enough’ according to survey participants. Commonplace horizontal field of view (50 degrees or lower) and commonplace vertical field of view (30 degrees or lower) are considered ‘good enough’ by fewer than 10% of surveyed population.

2. The lack of ‘good enough’ performance is cited in practically all the cases where buyers with appropriate budgets considered purchasing head-mounted displays yet ultimately did not do so.

3. Users consider the most important HMD attributes to be: panoramic field of view (over 100 degrees horizontal), large vertical field of view (over 50 degrees), very fast dynamic response (no smear or fade effects), high contrast display, high resolution display and a lightweight design.

A full copy of the survey can be obtained by contacting Sensics. I think it's well worth a read.

Saturday, July 28, 2007

Of Mice and Apes

At Sensics, my company, we get our fair share of curious inquiries. It's one of the fun parts about this business: every day the phone rings with someone eager to use our panoramic head-mounted display for a unique application.

A few weeks ago, someone called to ask about the range of our IPD (Inter-Pupillary Distance). Just like binoculars the often allow you to adjust the distance between the eyepieces to accommodate different individuals, head-mounted displays allow the same.
- "55 to 72 mm", we said
- "can you do an IPD in the 30 mm range?", said the caller
- "???"
- "well, I want to use the HMD on apes"

Just a few weeks went by, and another person called. After discussing the merits of immersion - high resolution and panoramic field of view - the caller asked whether he can use the HMD on mice.
- "So you want to use the HMD on mice?"
- "Yes"
- "???"

The thought of a mice wearing an HMD triggered many interesting visuals. Maybe mice can also wear football helmets? Is there a market for mice-sized HMD?

As interesting as this proposed research might be, we're going to stick with providing human an unmatched visual experience.

Friday, July 6, 2007

Industrial VR in France and Japan

We just returned from two exciting trade shows: the Paris Air Show (Le Bourget, France) and Industrial Virtual Reality in Tokyo, Japan. Hundreds of visitors came to experience how a high-performance head-mounted display enables engineers and designers to be immersed in their 3D data in the most realistic way possible (without actually building a physical version, of course).

In Tokyo, we were visited by
Many of engineers and executives from some of Japan's most recognizable companies including Canon, Mitusubishi, Honda, Sony, NEC, Toyota, Nissan, Mazda, Fujitsu, Hitachi, Ricoh, Epson, Toshiba, Nikon, Fuji, Brother and more. Similarly, in Paris, big aerospace giants came to see how VR technology can make a difference on the effectiveness of their designs, training systems, and products. Amazingly, our visitors in Paris were able to concentrate on the demo, even when test pilots where performing air stunts with the newest fighter jets and passenger airplanes.

An HMD for every engineer is still a long way ahead of us, but the interest level and excitement that these industrial giants make us all believe that mainstream virtual reality will become reality.


Wednesday, June 27, 2007

How Much Immersion is Enough?

Doug Bowman and Ryan McMahan of Virgina Tech wrote an interesting article titled "How Much Immersion Is Enough" which appears as a cover feature of July's IEEE Computer magazine.

They discuss several aspects of Immersion (defined as "the objective level of sensory fidelity a VR system provides") and presence ("a user’s subjective psychological response to a VR system") and talk about the main factors that drive immersion, including field of view, field of regard, resolution, stereoscopy, head-tracking, frame rate and more.

The article describes several studies that investigate how the degree of immersion impacts the performance of a person trying to complete complex tasks (such as planning the path of an oil well or visualizing a tunnel through rock structures) and describes the significant and measurable benefits attributed to higher degree of immersion.

It is nice to see measurable benefits tied to the "wow" feeling that people experience when they try on immersive head-mounted displays that offer both panoramic field of view and high resolution. My company has built several high-immersion models by optically stitching together small micro-displays. One unique side-effect of this approach is that during demonstrations, we are able to turn off individual displays and thus take a user through a full range of immersion options (e.g. from 150 degree field of view to 120 to 100 to 80) within seconds. This has been an excellent way to experience the benefits of true immersion.

Once you've had a chance to try a "business class" seat in an airplane, it's not easy to go back to economy. Similarly, once you try on an HMD or a CAVE with wide FOV, it will be difficult to go back to narrow displays.


Sunday, June 24, 2007

HMDs and "the last mile"

Remember the time that most home users could only use dial-up access to the Internet, even though the Internet backbone was very fast? These users could not enjoy the full Internet experience because of the bandwidth limitations in the "last mile" before their home.

Recent improvements in CPU and GPU power as well as rendering software, leads me to believe that the display quality of head-mounted displays could solve the "last mile" problem of bringing immersive virtual reality to the masses.

When I speak to audiences about head-mounted displays, I usually ask for a show of hands: "how many in the audience have Blockbuster or Netflx subscriptions or regularly rent movies?". A healthy majority usually raises their hands. "Now how many would still continue these subscriptions if all you had at home was a 3 inch black and white television?". Most hands come down. Without quality displays (with high resolution, wide field of view such as those offered by my company), the full potential of virtual reality will not be realized.