Nonlinear color mechanisms: a new model and a new method
Qasim Zaidi · Annual Meeting Optical Society of America · 1987
Selective desensitization experiments using sawtooth modulation have identified mechanisms that detect changes in one color direction but not its complementary (Krauskopf, 1980; Krauskopf et al., 1982). For example, along the constant-S line, one mechanism detects increments in (L-M) but not decrements, and another is its opposite. These mechanisms cannot be expressed as linear combinations of cone signals. One class of pairs of units that are compatible with the sawtooth results has responses that may be written as the positive derivative of the opponent response with respect to time.