Acuity correction is an important step in modelling receiver vision, and in the QCPA framework, controlling for the receiver’s spatial acuity, and the viewing distance. Initially developed in Matlab by Sönke Johnsen (Based on well-known Fourier math), later adapted for
Local Edge Intensity Analysis (LEIA)
The Local Edge Intensity Analysis (LEIA) measures edge intensities across a one-pixel-neighbourhood in four directions: horizontal, vertical and both diagonals. The contrast is measured as the Euclidean distance in the log-transformed Receptor Noise Limited (RNL) colour space and provided as
RNL Ranked Filter
The Receptor Noise Limited (RNL) Ranked Filter performs noise reduction while preserving chromatic or luminance edges, and is an important step in the QCPA framework. Importantly, it is also able to reconstruct sharp edges in images which have undergone smoothing
RNL Clustering
The RNL clustering technique was developed specifically for the QCPA workflow, parts of which require a colour image be segmented into different pattern elements or ‘clusters’. Unlike previous approaches this technique uses log receptor noise limited (RNL) modelling of Delta-S