SIGGRAPH 2008 > For Attendees > New Tech Demos > Superimposing Dynamic Range

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Superimposing Dynamic Range

Theme: SIGGRAPH Core
Hall H

A calibrated projector-camera system for automatic registration, scanning, and superimposition of hard copies. This project shows:
· How high-dynamic-range content can be split for linear devices with different capabilities.
· How luminance quantization can be optimized with respect to the non-linear response of the human visual system as well as for the discrete nature of applied modulation devices. · How inverse tone-mapping can be adapted when only untreated hard copies and soft copies are available.

This system achieves contrast ratios of over 45,000:1 with a peak luminance of more than 2,750 cd/m2, and it could technically reproduce more than 620 perceptually distinguishable tonal values. It attains color-space extensions of up to factor 3.3. Hard-copy resolution can be several thousand dots per inch, while luminance and chrominance are modulated with a registration error of less than 0.3 milimeters.

Enhanced Life
Paper prints are used in the medical field for exchanging information between specialists and general practitioners. This system achieves diagnostic quality of superimposed paper prints at a fraction of the cost of X-ray film, while outperforming the contrast of conventional X-ray film by six-fold.

To develop a method of viewing HDR content based on reflective image modulation. Compared to transmissive approaches, the system benefits from high light exploitation, high spatial-image resolution, and high contrast frequency. These are all essential factors for image visualization in professional fields such as radiology.

This generalized scheme for splitting HDR content for linear devices with different capabilities includes a luminance-quantization technique that maximizes the number of perceived tonal values while considering the discrete nature of the applied modulation devices.

In addition to improving existing hard-copy technologies in professional domains, this system could be appropriate for other applications of reflective HDR modulation. For example, personal photo albums or picture books could display HDR content and optical microscopes equipped with projector-camera systems could boost contrast when observing particular specimens so conservators have more detail when restoring paintings or historic prints.

Oliver Bimber
Bauhaus Universitet Weimar

Daisuke Iwai
Osaka University