An optical process whereby a seismic record section undergoes two 2D Fourier transformations to make another record section. A lens accomplishes the Fourier transform; see Figure L-2. If a grating is present in the object plane at the focal point of the lens, parallel rays will emerge and constructive interference will occur only at I0, I1, I2, etc., separated by a distance z which depends on the grating spacing. In optics, one usually thinks of white light separating into its frequency components as a result of passing through a uniform grating. In the Laserscan, monochromatic light passed through a nonuniform ‘‘grating’’ (e.g., a seismic record section) separates into the spacing components of the record section (as in f,k space). One lens thus accomplishes a Fourier transform of the record section and a second lens synthesizes the components back into a record section. By blocking certain components in the transform plane, their effect can be eliminated in the image plane. A laserscan can accomplish frequency or velocity filtering. LaserScan is a trade name of Conductron Corp. See Dobrin et al. (1965).