DTI’s Virtual Window 3D LCD Display — THG.RU

Introduction

3D computer graphics provides only a handful of cues to represent a virtual world: tricks of light and shadow, depth effects, culling of information outside of the view fustrum, and sorting the seen from the unseen with z-buffering. In reality, we see the world by combining the images formed by our left and right eye and get our perception of depth by viewing objects from two points separated by a few inches. Our brain takes care of the rest.

So, shouldn’t a truly immersive 3D experience include a way of recreating binocular vision? The subject has vexed computer scientists since 1965 when Ivan Sutherland demonstrated the first head-mounted display (HMD). Dimension Technologies Inc. has a unique approach to 3D display technology that doesn’t require cumberson headgear, or stereo glasses. DTI’s 2015XLS is a step in the direction of making 3D displays a reality for consumption outside of the scientific visualization, simulation, and virtual reality fields.

Before we take a closer look at the 2015XLS it is worth pointing out that stereo displays have been around for a while. Research on 3D display technology has been taken on by companies such as Sharp, and Philips. You can find a lot of information about research being done at Philips Research at the group’s 3D-LCD site. It’s a good place to get some background on general research trends in 3D LCD technology.

DTI Backgrounder

DTI was started by Jesse Eichenlaub and Arnie Lagergren in 1986. The company has been selling stereoscopic 3D LCD displays since the late 80s, and there are hundreds in use around the world. Until the introduction of the low cost 15″ 2015XLS, available since January of this year, most of DTI’s customers were deep pockets organizations like NASA, the military, and large R&D facilities. The DTI displays were quite expensive (the 18″ display retails for $6999), but the 15″ brings real depth LCD displays down to a consumer price, making it a pretty exciting breakthrough.

Mike Doolin, a spokesman for DTI, wanted to emphasize DTI’s technology leadership in this area, and told us, «DTI owns most of the world’s major patents on 2D/3D LCD autostereoscopic imaging. There are 14 patents already issued, 6 more in process and a very large pile of other technologies/ideas/stuff on Jesse’s desk that will get fed into the patent hopper as it is developed. The company with the next closest number of patents in this field has exactly one patent.»

The fact of the matter is that DTI seems to be the first company to market with a relatively affordable 3D LCD display, and that’s what piqued our interest. You can get much lower cost 15″ LCD displays (as low as $500), but does the 3D functionality add the extra value? That’s the question we tried to ask ourselves.

3D Display Technology

The basic technology for the 2015XLS is called parallax illumination. The two images — for the left eye and right eye — are sent to different columns of pixels, the left eye images to the odd numbered columns and the right eye to even numbered columns. An optical device called a TN panel is inserted between the standard LCD backlighter and the LCD panel itself, and the vertical columns on the TN panel illuminate either the even or odd columns of pixels, depending on which image is coming through. You can see this in figures 1 and 2. Your left eye sees only left eye images and your right eye sees only right eye images, just as you do in real life. This «fools» your mind into believing it is looking at a real life situation with real depth

Figure 1 (image courtesy of DTI)

Figure 2 (image courtesy of DTI)

Image courtesy of DTI

The stereo pair on alternate columns of pixels is generated at a rate of 60 frames per second, and on a 1024×768 display you end up effectively getting each image in 512 columns and 768 rows. Getting the separate images to each eye is achieved by using a lenticular lens on the TN panel. As a result, you end up a set of viewing areas where the process will work for you, as shown in Figure 3.

As a counterpoint, Cees van Berkel of Philips Research Laboratories in the UK pointed out that his company’s approach is to place a lenticular lens screen in front of the display to provide multiple views (i.e. more that the minimum two you require for stereo vision). By working behind the lens DTI allows you to use their panel as a 2D LCD display in full resolution; Philips’ solution doesn’t. By the same token, Philips’ can claim to offer a greater field of vision allowing more people to have access to the 3D image from a variety of angles, as well as maintaining full LCD brightness when 3D viewing. With DTI’s approach you obviously lose some brightness because you’re halving the number of columns delivering the light.

DTI 2015XLS Setup

Setup for the 2015XLS is relatively simple. The only difference from a normal display is that you have an extra RS-232 connector in the box that connects the display to an available COM port on your computer. The serial connection is required to activate the stereoscopic view, syncing and activating the illumination plane. Without the serial connection, or communications on your COM port with the DTI software, you won’t get 3D.

Another expectation the 2015XLS has is that you use the ELSA 3D Revelator generic driver for boards based on the Nvidia TNT/TNT2, GeForce and GeForce 2 GTS. Primarily the reason for using the ELSA drivers is that DTI has tested them and ELSA supports stereoscopic displays. I couldn’t get any more reasoning out of the company. I didn’t use the ELSA drivers initially, and didn’t have any problems on my Diamond Viper 770 Ultra using Nvidia’s own D3 driver. I wouldn’t expect much support from DTI on this one. The company’s Web site is not very well designed, and lacks any real technical information.

However, the most important expectation that the 2015XLS places on the user is that it requires you to keep an eye on a small red light positioned on the bottom right hand corner of the display. This light cues you whether you are sitting in the right position for 3D viewing or not. If you can see the light then you are not, and the most frustrating thing about the display is constantly having to be aware of this.

DTI includes a CD with demo images, and a couple of applications that let you manipulate images for 3D display. There’s something called TextureEyes which reads DirectX models and let’s you view them in stereo. If you want to import other file formats you have to convert them using an external utility. More for fun, I guess.

DTI 2015XLS Setup, Continued

The other application that comes on the CD is DTI’s Interactive 3D Image Processing Utility, or DTINT32I. This allows you to create one stereo image from two bitmaps, one for the left eye perspective, and one for the right eye perspective. Probably the nicest feature of this is the option to do a very basic slide shows.

I used AutoCAD 2000, ran the Mad Onion benchmark demo, and Unreal Tournament and Rollcage to get a feel for the display. The display should work with DirectX 5.0 games and up so, it seemed more appropriate to test the results with something less cutting edge. Static images, a number of which are included on DTI’s installation disk for demo purposes, work best. I have a feeling a lot of how it works for you will depend on how quickly your eyes, and brain maybe, adjust to the 3D effect.

The 3D works better when there isn’t a lot going on in the background, or there is an obvious contrast between the foreground and background object. So, if you have an object in front of a plain background, the 3D experience is going to be much more noticeable than if you have a foreground object against a very busy background of textures, and explosions and activity. Which means that you lose the impact of seeing 3D in a practical gaming situation. However, that doesn’t stop the 2015XLS from giving you a little jolt every time you switch to 3D as you see images appear to come out of the screen.

In full screen games you get the best experience, but in AutoCAD, or any other application where you may be working in a Window, you might be better off using the 2015XLS as a secondary display, and keeping the main application on a bigger, higher resolution display.

The screen defaults to 2D. In order to switch to 3D, something you can do on the fly, you have to change the monitor’s settings from the front panel. The assumption has to be that you are using the display as a normal 2D LCD at other times, which seems to be part of the attraction of the 2015XLS, that it can be used for general everyday use, and specialized 3D viewing. When you switch to 3D you do notice the image dim, and the effect of switching back and forth between 2D and 3D is a little disconcerting as a result. It’s a minor point, but it could be important if you were to use the display as your primary display for great lengths of time.

DTI 2015XLS Specs

The 2015XLS (image courtesy of DTI)

There is an on screen menu display that gives you access to Brightness, Contrast, Auto Adjustment, Geometry, Color, and 2D/3D Function Selection. The 2D/3D Function Selection gives you the option of specifying the 3D format of the display, and let’s you flip from 3D to 2D. In 3D mode, you can split the image up into top and bottom and side by side, and choose between frame sequential mode and field sequential mode.

Conclusion

The DTI 2015XLS does deliver crisp, clear, and headache free 3D images. It’s definitely a step-up from goggles and headgear, and the technology holds a lot of promise. It’s not ready for the mainstream, but it certainly points the way to the future.

I did consider the option of using this display for demonstrations and trade shows. It’s an eye catching solution, and there is the impact that a real 3D display would have on the audience. However, from any distance beyond being at arm’s length from it, you get a lot of reflection off of the screen. It isn’t apparent that there is something amazing going on. In one on one demonstrations or head-on use, the 2015XLS is a trip, but even though you have some freedom of movement sideways, you have to try hard to make sure that you are in an ideal position to get the full benefit of viewing in 3D. So, it takes some getting used to.

At $1699 the 2015XLS’ value for money proposition is very much dependent on what you are going to use it for. DTI seems to be trying to make a case for this product for gamers, but it seems a stretch to expect even the most hard core gamer to part with that much money for the cool factor. It’s definitely a luxury item, and not a necessity.

For people who need to have 3D displays for visualization, simulation, research, image processing, etc. this display must surely be a very desirable product. DTI has made real 3D very affordable for a large naumber of specialized users. If you are using your system for heavy design work it makes more sense to use the 2015XLS as a second screen because, it’s just too small for heavy use.

For this kind of display to find wider user and adoption it needs a big manufacturer to back it (and make it cheaper). DTI does license its technology, and that may be the best hope for this technology to find a broader audience. However, the 2015XLS gets high marks for opening our eyes to the possibilities of real 3D displays, even though it’s not quite ready for the masses.