A new system removes the headaches of current visualization displays.

Think visualization, and most users imagine large immersive-room environments driven by hardware with supercomputer-like performance. Like the software that drives such systems, current trends are for more compact, less costly visualization hardware solutions located closer to, or even in, the asset team room. Looking ahead, the next obvious step is for individual users to have their own 3-D visualization system on their desktop, enabling the proven benefits of reduced risk, increased productivity and improved return on investment to be seen at all stages of the exploration and production (E&P) workflow.
Stepping back in time
The underlying technology applied to 3-D visualization is not exactly new.
Not long after the invention of photography, the Victorians discovered the stereoscope (pioneered by luminaries such as Sir Charles Wheatstone and Sir David Brewster in the early 19th century). The stereoscope was an elegantly simple device whereby a 3-D image of the photographed scene could be visualized by acquiring two still images taken from a slightly different lateral perspective (achieved by moving the camera laterally between exposures) and then replayed (by direct viewing) through an optical assembly that was held to the user's eyes.
Somewhat surprisingly, perhaps, stereoscopy remains the most common method of 3-D visualization used today. Some big names have invested in developing alternative approaches, but stereoscopy remains the fundamental basis of the overwhelming majority of 3-D displays on the market today.
So, given it's the favored approach of most visualization vendors and has been around for nearly 2 centuries, why aren't we all working in 3-D or, more likely, watching 3-D on our home cinema systems? After all, who can argue with the inherent benefits that follow from the improved depth perception when viewing complex multidimensional datasets on a 3-D screen compared with a flat 2-D rendered image?
Current lack of adoption
Put simply, all 3-D displays require the user to compromise in some form or another - viewing apparatus, resolution, viewing angle, number of users, image depth, refresh rate, color reproduction, brightness, contrast, image and system size - the list goes on. And, of course, there is the additional cost of a 3-D solution compared with the existing screen. As a result, 3-D displays are pretty well consigned to opposite ends of the visualization spectrum - at one end, advertising or point-of-purchase displays that make the buyer say "wow;" at the other end, the equivalent of an Imax theatre in corporate headquarters.
Barriers to adoption
New adopters often cite collaboration, rather than the ability to view in 3-D, as the primary benefit of immersion in Hives, Caves or equivalent large-scale infrastructure systems. While the benefits of collaboration are certainly acknowledged, the understanding and ability to interrogate data with enhanced communication between disciplines in a 3-D team room environment would certainly not be so effective if 3-D visualization were not present. Until a body of evidence is produced which can quantify exactly where, and by how much, productivity is improved and costs and risk are reduced, all desktop 3-D hardware vendors will face an uphill struggle to gain traction in all but the most visionary of operators.
Part of the problem is numerous technical challenges and user complaints with the current systems. These include:
• User comfort - Need to wear glasses, problems with image cross talk (ghosting);
• Image quality and depth resolution - low resolution, screen reflections and poor contrast ratio;
• Ergonomics - Most systems are not 2-D/3-D switchable and have to be used under subdued lighting;
• Compatibilty - There are often problems interfacing with existing software/hardware; and
• User interface - The need to use a 2-D mouse in a 3-D environment.
There are also fundamental differences between the desktop and the immersive room environment. Working in an immersive room environment is akin to going to the theatre - how many theatre goers spend 5 days a week, 8 hours a day in the local Imax? Therein lies the fundamental difference between satisfying the needs of an immersive room user and those of a desktop 3-D display operator. The former is used primarily for data review and presentation - users are generally passive, visualizing but not actively interacting with the data, and sessions are limited to a few hours at most.
For an effective desktop solution, not only must users be able to operate for 8 hours a day on their personal 3-D workstation, but they must also be able to interact with their data in an intuitive way, and that means a 3-D mouse - some device whereby you can position your cursor in 3-D space and actually reach in and interact with your data, whether for seismic interpretation, reservoir modeling or well planning (Figure 1).
Data interaction
Geospatial imaging relies on the acquisition of two stereoscopic images from aerial or satellite photographs. Just as the Victorians did, such images are used to obtain depth relief when looking at buildings, topography or other ground-based features. While the generation of digital elevation models from such images has been largely automated, data quality control and final measurements for mapping are always made by a human operator - and for that they require to view and, more importantly, interact in 3-D. As a result, the traditional 2-D mouse has been replaced by thumbwheels, foot pedals and, more recently, 3-D mice - all set up to allow the operator to navigate and position the cursor in 3-D space. Highly specialized and tailored to geospatial imaging, such tools would not be readily portable to geoscience applications but do illustrate how improving the ergonomics of an input device can aid workflow in the 3-D environment.
Thinking a little further out ofthe box delivers a solution common to many product designers and conceptual artists - the haptic interface. Haptics enable the user to actually reach in and "feel" the data. Provision of a 3-D interaction device enables the user to pick, manipulate, control and even feel the data in three dimensions.
User comfort
The most common form of 3-D visualization hardware on the market today uses shutter or polarizing glasses. Both are effectively forms of filters that try to ensure the left eye image is only seen by the left eye and vice versa. Unfortunately, like all filters, they are inherently inefficient and so there is always some form of "leakage" such that the right eye can see some of the image destined for the left eye and vice versa - this is known as stereo cross-talk. The net result of this is that double images or ghosting will occur in the 3-D image to varying levels, depending on filter efficiency. This is at first distracting, and over time the presence of relatively small levels of cross talk can lead to physiological side effects such as visual discomfort, eye-strain and lack of concentration. This is not necessarily a major problem for an immersive room environment where users spend relatively short periods of time working in stereo mode, but it can be a major issue, not least from a health and safety perspective, if the user is working at a desktop 8 hours a day.
Glasses-free or autostereoscopic solutions do exist, most commonly based on a lenticular screen or parallax barrier placed over a LCD panel in order to redirect light to, or limit the light that can be seen by, each eye. Once again, however, such solutions also suffer from stereo cross-talk and so, whilst they may obviate the need for special 3-D glasses, the longevity of use and user comfort issue remains. Ironically, the optimum stereo viewing principal, in terms of having zero cross-talk, is the Victorian stereocope mentioned earlier. In this device, it is physically impossible for the left eye to see the right eye, so there is no inter-channel cross-talk.
New autostereoscopic displays
In recognition of the above end-user feedback, a new desktop 3-D display has been developed, shown in Figure 2, with the following properties:
• Glasses-free (no need for stereo glasses or HMDs);
• Exceptional user comfort (zero stereo cross-talk - work in 3-D longer);
• Very high resolution and image clarity (dual channel UXGA);
• Ease of use (large, easy to find, viewing zone);
• Environment (can be used under normal office lighting conditions);
• Cross platform compatibility (Unix, Windows, Linux); and
• 2-D/3-D switchable (can be used as normal desktop monitor).
Unlike other autostereoscopic displays that use lenticular screens or parallax barriers to achieve image separation, the new display utilizes a dual-channel projection system. By using this approach, each of the two stereo views can be displayed at full resolution and, most importantly, cross-talk between images can be eliminated. This results in exceptional image resolution, clarity and user comfort.
The principal components of the system include a projection engine that occupies the space under the user's desk and consists of image sources, relay mirrors and projection lenses. The head unit sits above the desk and contains a beamsplitter and concave mirror. The concave mirror acts as a directional screen, forming a system exit pupil through which the user looks to see in 3-D. The vertical position of the exit pupil may be adjusted by the user to give the optimum viewing position.
Conclusion
The advent of lower-cost, higher-performance computers has enabled high-end visualization software tools to be deployed to the desktop. The current trend is for smaller-scale visualization hardware to be located adjacent to team rooms, delivering the power of visualization to the heart of the asset team. This trend has the potential to evolve into desktop solutions which enable individual geologists, geophysicists and drilling engineers to have immediate access to visualization room type performance on their desktop.
For more information, visit www.iris3d.com.

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