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. 2017 Nov 2;17(13):4. doi: 10.1167/17.13.4

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(A) Full model. A 2D luminance profile first goes through a luminance compressor (LOG: luminance logarithmic function), and then, after filtering through multiple LoG (Laplacian of Gaussian) filters, in each channel, one eye's (e.g., LE) signal receives contrast-and-luminance gain-control (CLG, blue path) and gain-enhancement (CLG, red path) from the other eye (e.g., RE). The gain-control depends on the product of the total contrast energy (TCE) and total luminance energy (TLE), which are both weighted sums over the space and spatial-frequency domains. The gain-enhancement only depends on the TCE. The RE's gain-control (blue) and gain-enhancement (red) themselves are gain-controlled by the LE with gain-control efficiency and respectively if we assume the gain-control efficiency = 1 in the LE's signal path (black). Only half of the DSKL model for LE's output is shown, and the other half for RE's output is symmetric to the LE's half. The first-order binocularly combined profile is the linear summation of the two monocular output profiles, and the second-order binocularly combined profile is the linear summation of those after rectification in each eye before binocular combination. (B) Calculation of TCE and TLE. For TCE (total contrast energy), a 2D compressive luminance profile is first filtered by LoG (Laplacian of Gaussian) filters, rectified, and then normalized by the mean luminance to give a contrast profile. For each spatial-frequency channel, the local contrast at each point in space is raised to the power of gamma, and then the contrast energy for this channel is calculated as a weighted sum over the two dimensional space (CSWF: contrast space weight function). The TCE is a weighted sum over spatial-frequency channels (FMTF: spatial-frequency modulation transfer function). For TLE (total luminance energy), the luminance value at each point in space of the compressed 2D luminance profile is raised to the power of eta, and then the TLE is calculated as a weighted sum over the two dimensional space (LSWF: luminance space weight function). The product of TCE and TLE is calculated for the gain-control path, whereas the gain-enhancement path only needs TCE.

Inline graphic — (A) Full model. A 2D luminance profile first goes through a luminance compressor (LOG: luminance logarithmic function), and then, after filtering through multiple LoG (Laplacian of Gaussian) filters, in each channel, one eye's (e.g., LE) signal receives contrast-and-luminance gain-control (CLG, blue path) and gain-enhancement (CLG, red path) from the other eye (e.g., RE). The gain-control depends on the product of the total contrast energy (TCE) and total luminance energy (TLE), which are both weighted sums over the space and spatial-frequency domains. The gain-enhancement only depends on the TCE. The RE's gain-control (blue) and gain-enhancement (red) themselves are gain-controlled by the LE with gain-control efficiency and respectively if we assume the gain-control efficiency = 1 in the LE's signal path (black). Only half of the DSKL model for LE's output is shown, and the other half for RE's output is symmetric to the LE's half. The first-order binocularly combined profile is the linear summation of the two monocular output profiles, and the second-order binocularly combined profile is the linear summation of those after rectification in each eye before binocular combination. (B) Calculation of TCE and TLE. For TCE (total contrast energy), a 2D compressive luminance profile is first filtered by LoG (Laplacian of Gaussian) filters, rectified, and then normalized by the mean luminance to give a contrast profile. For each spatial-frequency channel, the local contrast at each point in space is raised to the power of gamma, and then the contrast energy for this channel is calculated as a weighted sum over the two dimensional space (CSWF: contrast space weight function). The TCE is a weighted sum over spatial-frequency channels (FMTF: spatial-frequency modulation transfer function). For TLE (total luminance energy), the luminance value at each point in space of the compressed 2D luminance profile is raised to the power of eta, and then the TLE is calculated as a weighted sum over the two dimensional space (LSWF: luminance space weight function). The product of TCE and TLE is calculated for the gain-control path, whereas the gain-enhancement path only needs TCE.