| Abstract
The conventional quantizer design based
on average error minimization over a training set does not guarantee a
good subjective behaviour on individual images even if perceptual metrics
are used.
In this work a novel criterion for transform
coder design is analyzed in depth. Its aim is to bound the perceptual distortion
in each individual quantization according to a non-linear model of early
human vision. A common comparison framework is presented to describe the
qualitative behaviour of the optimal quantizers under the proposed criterion
and the conventional rate-distortion based criterion. Several underlying
metrics, with and without perceptual non-linearities, are used with both
criteria. Analytical results show that the proposed design criterion gives
rise to a JPEG-like quantization if a simple linear metric is used. Experimental
results show that significant improvements over the perceptually weighted
rate-distortion approach are obtained if a more meaningful non-linear metric
is used.
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