An optically readable system and method to allow for the remote identification of people and/or objects is disclosed. The system includes a spectrally continuous source of radiation generating an interrogating beam, an optically readable device carried by a person or attached to an object and having a unique spectral signature and, generating a retroreflected beam when exposed to the interrogating beam, and an optical spectrum analyzer and decoder for identifying the unique spectral signature of the interrogated optically readable device and for transmitting the identifying information to a display and/or a computer input. The spectrally continuous source of radiation can comprise a tungsten filament lamp, a tunable laser or the like. If covert identification is desired, the source is operated to generate an interrogating beam in the infra-red spectrum only.

A method of visually representing output data on a screen by deflecting a laser beam in both horizontal and vertical directions for scanning, and an indicating device for performing the above method. The laser beam is first divided into two polarized waves which are, after being modulated in accordance with the output data, combined into a first synthesized laser beam. The two polarized waves are alternately extinguished synchronously with a predetermined simple harmonic oscillation. The synthesized laser beam is then horizontally deflected by means of a sinusoidally oscillating mirror so that the angular displacement of the deflection oscillates in synchronism with the predetermined simple harmonic oscillation. The resultant deflected beam is again divided into two polarized waves, one of which is then inverted. The resulting two polarized waves are combined to obtain a second synthesized laser beam whose angular displacement in deflection is unidirectional at any phase. The second synthesized laser beam, after being vertically deflected, is projected on the screen for scanning.

This disclosure is concerned with improved bottom-edge margin indicators for typewriter paper and the like using an optical sensor-monitor wherein spurious effects of the edge of the paper exiting from the bottom margin sensor region and pre-printed material thereon are obviated, and in which the sensor-monitor of the bottom edge of the paper is preferably carried by the platen shield itself in manner that is particularly advantageous for optical sensing of the paper, with the sensor maintained in extremely closed proximity to the paper irrespective of its thickness, and adapted for simple and ready adjustment, if desired, to vary the margin setting.

A flat bed scanner system for optically sensing a transparent original image and producing three channels of binary digital data representing the densities of the original image. Each channel produces data in response to one sensing color and sensing of the original image occurs by directing a focused image of a beam of white light onto and across the original image in a pattern of parallel scan lines there being a plurality of sensing positions along each scan line, and producing the digital output data in response to the modulated beam of light transmitted by the original image. There is an optical system which provides for the directing of the beam of white light across the original image and which directs the modulated beam onto sensors. The optical system includes color correction and field flattening of the beam of white light and provides a cylinder condenser lens for the modulated beam of white light. An electronic system receives signals from the sensors and converts them into the desired digital data through analog to digital and logarithmic conversion circuits, base line correction circuits and references compensation circuits. The electronic system also provides a sample clock signal synchronizing the locations of the sensing beam with the locations of the sample positions by way of an optical grating system. An electromechanical system is provided to maintain the optical system in focus from scan line to scan line on both the original image and the optical grating system.

A surface scanning system defining an optical path for scanning a planar surface, in which an angularly moving scanner deflects a portion of the path, an optical element aligned with stationary portions of the optical path is driven in rectilinear sinusoidal motion for providing focus correction as the surface is scanned, and in which the sinusoidal motion of the optical element and the motion of the scanner are caused to be interdependent in frequency and phase. The sinusoidal motion of the optical element maintains accurate focus on the planar surface. In another aspect a device for moving an optical element in linear resonant motion includes a cantilevered resilient support structure arranged to permit only linear motion of the element, and means for driving the element resonantly. In another aspect apparatus for detecting the position of a beam being scanned on a surface includes oscillator means whose frequency is synchronized to the changing velocity of the scanning on the surface, and means for switching the oscillator to its maximum resolution frequency during portions of the scanning when the beam is not within an active area of the surface. In another aspect, the reading or writing on the surface occurs only at times during which the optical element is not at its maximum negative excursion.