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Incoherent color image correlation with a multiwavelength Fresnel holographic filter and a color liquid-crystal television as a real-time input device is demonstrated.

The diffraction efficiency of volume gratings written by two-wave mixing in a cerium-doped potassium sodium strontium barium niobate (Ce:KNSBN) photorefractive crystal is studied. It is found that the diffraction efficiency strongly depends on the polarization of writing beams and exhibits loop behavior with respect to the fringe modulation. The fringe modulations before and behind the crystal are compared. Modified coupled-wave theory is used to fit the experimental data. This research presents data that are relevant to the application of Ce:KNSBN crystals to holographic recording and optical information processing.

There is a great deal of interest in the sunlight readability of displays. How to quantify this, particularly on a numerical scale rather than pass/fail is an important consideration. Some military standards exist e.g. MIIL-L-85762A1 but are these appropriate to non-military products? We report the use of a method developed by BAE SYSTEMS2'3'4, the model is based on our ability to see things by virtue of a difference in either luminance or chrominance, or both. The model uses a method called PJND (Perceptible Just Noticeable Difference), based on LJND (Luminance Just Noticeable Difference) and CJND (Chrominance Just Noticeable Difference) thresholds.The basis of this model is a series of acceptance criteria established by subjects in a realistic environment; BAE SYSTEMS have an Ambient Lighting Facility (ALF) which simulates many lighting scenarios that are likely to be encountered in real life. Product mock-ups were taken into this environment and subjects were asked to choose levels of acceptance for differing screen presentations and various lighting geometries. The method results in a single figure of readability, which in effect summarises the task and environment. This figure can then form the basis of a specification between display supplier and vendor.We plan to develop the model such that it should be possible to predict the best combination of treatments to apply to the display surface to give the optimum and most cost effective sunlight readable display for a given application and product.