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t q A model is developed to approximate visibility thresholds for discrete cosine transform (DCT) coefficien uantization error based on the peak-to-peak luminance of the error image. Experimentally measured visibility thresholds for , , and DCT basis functions can be predicted by a simple luminance-based detection R G B model. This model allows DCT(More)
A semiautomated computer analysis was developed to estimate fluid volumes in each hemicranium from computed tomography scans. The method was used to estimate total ventricular and sulcal fluid in 123 normal subjects aged 23-88 years. A wide range of normal values was found. The trend was for the estimated ventricular and sulcal fluid volumes to remain(More)
Nonlinear contributions to pattern classification by humans are analyzed by using previously obtained data on discrimination between aligned lines and offset lines. We show that the optimal linear model (which had been identified by correlating the noise added to the presented patterns with the observerÕs response) can be rejected even when the parameters(More)
The aim of the ColorFest is to extend the original ModelFest (http://vision.arc.nasa.gov/modelfest/) experiments to build a spatio-chromatic standard observer for the detection of static coloured images. The two major issues that need to be addressed are (1) the contrast sensitivity functions for the three chromatic mechanisms and (2) how the output of(More)
any standard image compression techniques i apply the Discrete Cosine Transform (DCT) to the mage, then quantize the resulting transform coefficients. b For optimal compression, the DCT coefficients should e quantized as coarsely as possible, while allowing. Q minimal visible distortion in the decompressed image uantization of a DCT coefficient induces a(More)
Will a simple global masking model based on image detection be successful at predicting the readability of transparent text? Text readability was measured for two types of transparent text: additive (as occurs in head-up displays) and multiplicative (which occurs in see-through liquid crystal display virtual reality displays). Text contrast and background(More)