Battle of the Headsets: an informal evaluation of the latest budget-level HMDs

Chen T., Gadd A., Poupyrev I., and Fels S.

Media Integration and Communication Research Laboratories,

ATR International, Kyoto, Japan

Inexpensive, consumer-oriented head mounted displays (HMD) arrived when Seattle-based Virtual I/O introduced their i-glasses headsets. The i-glasses HMD could be used both in mono and stereo, either in see-through or in opaque mode; it also featured stereo sound, head tracking, and a robust, light-weight and highly ergonomic design all together for only $800.

With other HMDs carrying price tags far above $1000 level, the i-glasses was an instant hit in the VR community, receiving rave reviews; it in fact created a whole new market of budget-level HMDs. This, however, was not enough to keep the company afloat, as Virtual I/O closed down a few years ago.

Recently the activity on the market of consumer-oriented HMDs has been rapidly heating up with heavyweight players such as Sony, Olympus and Canon offering a gallery of the newest headsets in the budget-level HMD category. In this article we pitted the latest HMD offerings against one another, evaluating them from the perspective of the end-user. Our evaluation is rather informal—the objectives were to see what the new generation of entry-level HMDs offers, to compare their usability and comfort, and determine their relative strengths and weaknesses.

The reviewed HMDs are not yet generally available outside of Japan, thus this review can offer an opportunity to get a close-up look at the newest products.

The HMDs

Three HMDs were surveyed: the Sony Glasstron PLM-A55, the Canon GT270, and the Olympus Eye-Trek FMD-100. All three headsets are touted as ultra-portable devices for viewing video, and sold in electronics stores in Japan next to portable DVD players, hand held TVs and digital camcorders. Currently, none of these units are directly available in the North American market.

Sony Glasstron PLM-A55

The Glasstron PLM-A55 is one of three displays that Sony is producing today. It is the only Sony HMD which is widely available in retail and priced below $1000. The other two models—a high-resolution and a stereoscopic version—are significantly more expensive and are not discussed in the article.

Introduced this summer, the Olympus Eye-Trek FMD-100 is the latest version of the Olympus Eye-Trek display, which is starting to become available in Europe. Together with FMD-100 Olympus also introduced a more expensive model Eye-Trek 150W which has a wider field of view; we do not review this model here.

Olympus Eye-Trek FMD-100

While Olympus and especially Sony have been in the HMD market for a while, the Canon GT270 headset is the first HMD offered by Canon. In common with the Olympus Eye-Trek, the Canon GT270 uses an aspherical lens design which, while resulting in a compact and light display, does not allow for a see-through mode à la the Sony Glasstron.

Cannon GT270

Basic operation

Each headset takes a standard NTSC signal which is fed into a control unit via composite or S-video jacks. Besides the video input the control units usually have plugs for power, external headphones, and battery. Each of the headsets also offers an extensive built-in menu system that allows for image and sound adjustment. The menu can be navigated via the dials on the control unit: jog dials on Sony and Olympus have jog dials, and a cute button that is similar to a joystick on Canon. We were somewhat surprised to find a password protection option on the Olympus and Sony headsets that allows set up a password preventing use of the headset. For such personal units, password protection is perhaps an excessive feature; furthermore, it can be easily overridden (editor’s note: this feature makes more sense in a European or US context, were there has been concern about the possible adverse effects of prolonged use of HMDs, especially by children).

All three units can be operated on battery power with battery packs attached to the control units. Surprisingly, none of the control units seemed to have belt clips, which might have significantly aided mobile users.

Out of the three units, the Sony display is the only unit that can be used in see-through mode. The Glasstron viewing unit is translucent and has a shutter that can be opened and closed. Closed, the unit operates like the other two HMDs; open, the shutter allows the user to see the real world through whatever is displayed on the screen.

Image quality

One of the questions we wanted to answer was whether there is any significant difference between the headsets in terms of the image quality, color balance, and how well we could read text on the display. To evaluate the image quality of the headsets, we connected them to the video output of an SGI O2 workstation and displayed three types of images: first, a general photographic image; second, an abstract image with vivid colors to see how close the displays can reproduce the color compared with the monitor; and third, an image composed of various sizes of text and lines.

All the headsets demonstrated quite impressive image quality, though of course, the quality of the image can not be compared to the quality of the high resolution desktop monitors. Instead, comparing them with Virtual I/O i-glasses we found that the color, brightness and contrast of the head-mounted display images were superior for all three displays evaluated.

One of the test images used for display evaluation

Even though the difference between the image quality for all displays was rather negligible, we preferred Sony Glasstron for the color image quality. After adjusting the brightness controls in the menu we were able to get the Sony to reproduce the abstract color image quite accurately. For the general photograph, the Sony's image was somewhat pale, which might be improved with contrast control, which, however, was lacking in the Sony Glasstron menu.

Contrast, on the other hand, was excellent on the Canon, which presented vivid, rich colors. It displayed the photographic image best, with a comfortable brightness and contrast balance. The Olympus’ default output seemed somewhat washed out and pale compared to the other two displays. A reasonable approximation was obtainable only after manipulating the numerous picture controls, and even then, the image was not as good as the Sony’s, which, did not require as much adjustment. With the text test image, we found that 12-point font was legible on all displays. Again, the quality of the image seemed best for Sony Glasstron as it produced the most stable and easy to read image, with sharp lines and text. The Olympus output seemed blurrier than the Canon or Sony.

Olympus Eye-Trek menu system

The ability to customize display configuration using built in menu systems is one of the winning points of reviewed displays: even many of the high-end HMDs do not provide the level of customization that is available on the headsets we surveyed. All displays provide controls and menu systems to adjust the quality of image with different degrees of sophistication, providing brightness, contrast, color tone, and color intensity controls. The Sony did not provide any contrast control, but otherwise the controls were adequate. The Canon, in addition to all the controls provided by Sony, had a contrast control, as well as four presets including ones for movies, anime, and outdoor images. The Olympus more than makes up for its menu-less predecessor, by offering the most comprehensive menu system, which allows for fine picture adjustment. Furthermore, you can choose between English and Japanese as the operating language. Curiously, brightness is considered an "expert" control item, whereas contrast is so basic, the default action of the jog dial is to adjust the contrast! Furthermore, the Olympus also allows users to save custom settings for later retrieval.

Audio

All three headsets have loudness toggles, which the Olympus dubs “Bass Control.” Surround sound is available on the Sony and the Olympus. The sound quality is quite good on the Sony and the Canon, while the Olympus' is surprisingly poor. Furthermore, the Olympus is also the only unit without a headphone jack.

When the earphones are not in use, the Olympus and Canon clip them onto the arms; we found the Canon’s wires were in the way when we were putting the headset on. The Sony system was the best, retracting its earphone cables neatly into the arms and pulling the earphones into little sockets. Unfortunately, the earphones didn’t clip into position securely, so they sometimes fell out of the sockets and dangled. Generally, however, the earphones can be just left in their clips. With the volume turned up, they are reasonably audible, though they may not produce quite enough volume to overcome background noise.

Ergonomics and ease of wear

If the glasses are to be used regularly then ergonomics and ease of wearing become key issues—probably much more important then the differences in image quality or feature set.

The rigid eyeglass-like design of the Olympus Eye-Trek makes it very compact and extremely easy to put on and take off—it is the lightest display among all three. To secure the headset a head strap can be attached using the holes on the arms; however, the head strap was not provided with headset. Extended usage of the Olympus headset might be somewhat difficult because the entire weight of the unit rests on a small rubber pad on the bridge of the nose, which is uncomfortable after a while, especially for those who wear glasses. The nosepiece can be actually extended to support glasses, which does make it more comfortable. Also, unlike normal eyeglasses that come in different sizes, the Olympus is designed for the average user and we found that people with small heads, e.g. children, may have difficulties wearing the unit.

The retractable nose piece of the Olympus headset

Unlike Olympus, both Sony and Canon use a forehead pad and a strap encircling the head, with the display unit hanging from the forehead support. The Canon’s two arms can be connected by a Velcro strap, which allows the unit to be tightened up securely around the head. The Sony uses a clever system where the arms are extendible which, in combination with the fixed connecting back strap, allows the user to snug the strap around the head by shortening the arms. Although the Sony’s system felt very comfortable and secure after the headset was put on, it was certainly not as intuitive and easy to understand as the Olympus or Canon.

The visors on the both Sony and Canon can be flipped up, which we find very useful when working on several things at the same time. The Sony actually uses a double hinge assembly, allowing more positioning freedom than the Canon. The Olympus’ rigid design, while having the advantage of simplicity, means that the headset must be removed to be able to see anything else comfortably.

Concluding remarks

It was impossible to determine a clear winner among the three headsets we surveyed. Each has its own merits and the results are presented in the table below. The Sony’s telescoping arms and retractable earphones make it more comfortable for prolonged wear, but the user must first learn how to operate these mechanisms.

The choice of the headset depends on your application. If you need a quick, easy-to-use headset for brief presentations, look at the Olympus: in a situation where the user is donning the unit for the first (and possibly last) time, the Eye-Trek headset and, to a degree, the Canon is very simple and intuitive to use. This is especially true for the Olympus display, which wears just like a pair of sunglasses and, therefore, there is no need to know how to use the headset, the operation can be started immediately.

If you want something to use on a regular basis, the Sony would probably be our choice, being more comfortable with its double hinge and telescoping arms. Canon is a good compromise between the two in terms of features, ease of use and especially price.

What is certain is that low-cost HMDs have reached a certain level of maturity, quality and especially, price level that they can compete on par with the more expensive high-end HMDs in many applications. With development continuing, prices decreasing and the quality improving, the future of affordable virtual/augmented reality systems is brighter then ever. We eagerly wait for new developments.

TECHNICAL SPECIFICATIONS

	Sony Glasstron PLM-A55	Canon GT270	Olympus Eye-Trek FMD-100
Dimensions (WxHxD, mm) of display unit	165x56x110	171x86x66	170x50x55
Dimensions of controller unit	53x30x149	55x39x110	51x33x128
Mass of display unit (g)	150	150	110
Mass of controller unit	110	90	80
Display panel	TFT	TFT	TFT
Horizontal field of view	30^o	30^o	35^o
Vertical field of view	22^o	22^o	26.6^o
Virtual screen size (in)	52	52	62
Simulated viewing distance (m)	2	2	2
Dot pitch	0.6	0.6	n/a
Pixels (each panel)	180,000	270,000	180,000
List price	Y77,000	Y85,000	Y69,800
Street Price (yen)	Y70,110	Y54,500	Y79,800

EVALUATION RESULTS

	Sony Glasstron PLM-A55	Canon GT270	Olympus Eye-Trek FMD-100
Overall image quality	1	2/3	2/3
Wearing comfort	1	2	3
Ease of use	3	2	1
Portability	2/3	2/3	1
Sound, earphones	1/2	1/2	3
Image adjustment	3	1	2
Sound adjustment	2/3	1	2/3
English menus	No	No	Yes
S-Video input	No	Yes	Yes
Headphone connection	Yes	Yes	No
See-through mode	Yes	No	No
Surround sound	Yes	No	Yes

The ranking was 1 – the best, 2 – the middle, 3 – the last