Authors: (María Gabriela Lagorio, INQUIMAE/ Dpto. de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II, Buenos Aires, Argentina)
Abstract: The signal generated in eyes photoreceptors may be inferred from a physical quantity defined as Quantum catch. This quantity represents the proportion of incident photons that are captured by the photo-pigments at each photoreceptor. For the calculation of Quantum catches, the reflectance spectrum of the observed object, the spectral sensitivities curves of the photoreceptors and the spectrum of the illuminating light must be considered. In this chapter, the experimental determination of Quantum catches is presented in detail. Additionally, the concept of Quantum catch is reviewed and discussed in relation to the modeling of animal´s vision, color matching, sexual dichromatism in avians, magneto-reception in birds, and visual disorders in humans as retinitis pigmentosa and Vitamin-A deprivation. Quantum catches are useful quantities to find the relative contrasts against fruits or flowers and background and they are strongly connected with the bio-signals received by the avian fruit consumers and pollinators. The use of Quantum catches to obtain ―receptor images‖ is also included.