Definition and use of spatial frequencies in Fourier Optics and in Physiological Optics

SILVIANA COMASTRI; J. M. SIMON; GABRIEL MARTIN; ELISA COLOMBO; LUIS ISSOLIO; JAVIER SANTILLÁN; ROLANDO AGUIRRE

Óptica Pura y Aplicada

Sociedad Española de Óptica

Lugar: Madrid; Año: 2007 vol. 40 p. 119 - 128

0030-3917

Spatial frequencies are often employed both in Fourier Optics and in Physiological Optics. According to Fourier Optics, any object can be synthesized as a superposition of harmonics of different spatial periods and the spatial frequency, defined as the inverse of the corresponding period, is measured in cycles per millimeter. On the other hand, in Physiological Optics, the spatial frequency is the inverse of the angle subtended at the eye of the observer by a cycle of a sinusoidal grating and its units are cycles per degree. In the present paper, the definition of transfer functions and spatial frequencies and the relations between the cutoff spatial frequencies and the limits of resolution used in both disciplines are analyzed and compared. Applications of Fourier theory in optical design (production limited microscopes) and also in visual quality tests (contrast sensitivity) are shown.