Anders Ballestad

Calibrated image appearance reproduction

Managing the appearance of images across different display environments is a difficult problem, exacerbated by the proliferation of high dynamic range imaging technologies. Tone reproduction is often limited to luminance adjustment and is rarely calibrated against psychophysical data, while color appearance modeling addresses color reproduction in a calibrated manner, albeit over a limited luminance range. Only a few image appearance models bridge the gap, borrowing ideas from both areas. Our take on scene reproduction reduces computational complexity with respect to the state-of-the-art, and adds a spatially varying model of lightness perception. The predictive capabilities of the model are validated against all psychophysical data known to us, and visual comparisons show accurate and robust reproduction for challenging high dynamic range scenes.

Efficient, high brightness, high dynamic range projection

Projection is a popular form of imaging but suffers from dim peak light levels and poor contrast, limiting effective use to dark and controlled viewing environments like the cinema (Figure 1). We introduce a novel High Dynamic Range (HDR) projection technique that achieves both dark black levels and very bright peak luminance in an energy and cost efficient implementation.

High brightness HDR projection using dynamic phase modulation

We demonstrate a new, large screen projection technology that utilizes dynamic phase modulation for light steering to achieve both black levels indiscernible from the screen in dark environments and peak luminance levels some 20 times above what conventional projectors can reach with the same light source. The human visual systems near-logarithmic brightness response to luminance is demanding on the lamp requirements in a conventional display system. With a steerable light source, excess light from dark areas in an image can be used for areas requiring higher brightness thus breaking the conventional linearity between out-of-lens-lumens and onscreen-luminance. We will demonstrate our new, full color prototype which reproduces very realistic appearing images and requires only a fraction of the energy of a traditional projector (Figure 1).