Improved Visible Differences Predictor Using a Complex Cortex Transform

Prediction of visible differences involves modeling of the human visual response to distortions in the image data. Following the approach of Daly [1], this paper introduces several algorithm improvements allowing for more accurate calculation of threshold elevation and modeling of the facilitation effect during phase-coherent masking. This is achieved by introducing a complex-valued cortex transform that separates the response magnitude from the instantaneous phase within each band of the cortex transform. The magnitude component is used for calculation of the mask contrast. The phase component takes part in modeling of the facilitation effect.