Two weighted compression schemes, Weighted Least Squares (wLS) and Weighted Principal Component Analysis (wPCA), are compared by considering their performance in minimizing both spectral and colorimetric errors of reconstructed reflectance spectra. A comparison is also made among seven different weighting functions incorporated into ordinary PCA/LS to give selectively more importance to the wav...

A follow-up study of colour vision in two patients with gyrate atrophy was performed. Gyrate atrophy was diagnosed in the first patient at the age of 17 years. Her colour vision was first tested at the age of 25 years; at the follow-up examination 7 years later, she correctly interpreted the Standard Pseudoisochromatic Plates part 2, however, with one mistake due to lens opacity. In the Farnswo...

The effects of glaucoma and diabetes on the sensitivities of the opponent and achromatic systems were investigated by measuring thresholds along theoretically defined axes in a three-dimensional color space. Thresholds were measured along two equiluminant chromatic axes and one achromatic axis in patients with diabetes or glaucoma and in glaucoma suspects. The results were compared with measure...

This study examines the influence of ascorbic acid pretreatment on ethanol clearance, toxicity, and behavioral impairment after an acute dose of ethanol in humans. Ascorbic acid or a placebo was given to 20 healthy male subjects for 2 weeks before ethanol consumption. The dose of ethanol was 0.95 gm/kg body weight and was consumed during a 2 1/2-hour period. Thirty minutes after ethanol consump...

A Color Quality Scale (CQS) is being developed at NIST, which evaluates several aspects of the quality of the color of objects illuminated by a light source. This metric involves several facets of color quality, including color rendering, chromatic discrimination, and observer preferences. The method for calculating the CQS is derived from modifications to the method used in the CIE's Color Ren...

High Dynamic Range (HDR) images use a wider range of intensity values than the common Limited Dynamic Range (LDR) images. Because of this, handling HDR images requires a great deal of information to be stored and transferred. To represent and display HDR images efficiently, a trade-off needs to be balanced between size and accuracy. We present a new wavelet-based algorithm for encoding HDR imag...

A two-alternative forced choice experiment is planned to determine if diagnostic benefits exist when using a high dynamic range display for a lesion detection task. The potential benefits resulting from both an increased dynamic range and an increased number of displayable just noticeable grayscale differences will be evaluated. A custom built high dynamic range display system, constructed at t...