Abstract: Shade or tint intensities in holograms are calibrated by an array of calibration pixels in each hologram. The preferred array consists of crossed lines of the calibration pixels in the hologram disposed to cover all critical portions of the hologram. An optical processing apparatus employing a hologram having an array of calibration pixels is disclosed.

Abstract: A holographic unit includes a planar array of hologram/sections disposed along a central axis. A pair of parabolic arrays of planar mirrors are symmetrically disposed on opposite sides of the hologram array such that all planar mirrors face respective ones of the hologram/sections. A hologram emitter transmits hologram-inducing light to mirrors in a first one of the parabolic arrays, and a hologram receptor receives hologram/light emitted from the hologram array via mirrors in a second one of the parabolic arrays. The emitter and receiver are respectively disposed at the focal points of the parabolic arrays. The emitter and receiver have planar arrays of photoelements oriented at identical angles with respect to the hologram array and respectively facing the mirrors. The planar array of holograms may be used for storing or processing information-bearing signals.