November 3, 2004 One of the measures used to determine how realistic a monitor can display an image is its dynamic range. This essentially measures the difference between the lightest and the darkest pixel on the screen. Most monitors have a dynamic range of between 300:1 or 400:1, but the Sunnybrook HDR display is a staggering 40,000:1. In real colour terms the Sunnybrook monitor offers over 30 times higher brightness than any commercially available display technology, while at the same time allowing for a black that is over 10 times darker than that of conventional displays.
The images are incredibly rich and lifelike, which comes in very handy as MCAD software continues to demand higher rendering quality.
The medical imaging industry, also, has long been seeking a display with HDR’s dynamic range capabilities. The human body features a high dynamic range of density and medical images need to accurately represent that density range. Current medical imaging, processing and networking facilities support high dynamic range but displays do not. HDR is the missing link that allows full digital medical imaging.
For film post-processing, the improved dynamic range can reduce the number of editing iterations by more accurately representing images on film.
How it works
Flat panel LCD computer displays modulate (filter) light coming from a constant and uniformly bright backlight, which usually consists of one or more fluorescent tubes behind the LCD glass.
In Sunnybrook’s HDR display, this simple backlight is replaced by a controlled array of ultra-high brightness white or tri-colour light emitting diodes (LEDs). These current-controlled diodes are capable of generating over 200,000 cd/m2 at maximum current and emit no light in the off state.
The LEDs are arranged in an array where each LED’s luminance can be individually controlled at video refresh rates. This LED backlight array effectively constitutes a low-resolution, but very high brightness display. This low-resolution white-light LED image is then projected through a standard colour LCD panel, which displays a similar, but high resolution, version of the image.
Each individually controlled LED backlights a small region of the LCD panel. This has the effect of multiplying the modulation of the two displays which provides the substantial gain in dynamic range.
Thanks to software correction algorithms and the natural effects of scattered light in the human eye the blur introduced by the low resolution LED image is imperceptible, and the result is a high resolution, high dynamic range final image.
The HDR display accomplishes an 100-fold improvement in dynamic range by leveraging the optical properties of standard components, yet is completely compatible with existing computer video cards.
High Dynamic Range (HDR) is a groundbreaking emissive display design developed by SunnybrookTechnologies in collaboration with the University of British Columbia in Vancouver, Canada.
For more information see: www.sunnybrooktech.com
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