For obtaining distance information between an image pickup device (10) and an object (11) illuminated by a monochromatic beam selected by a diffraction grating (18) from an optical beam generated by an optical beam generator (27), a distance information obtaining device comprises an activating device (33) for simultaneously activating the beam generator and the image pickup device a predetermined time duration so that the optical beam generator generates an optical beam while activated and so that the image pickup device picks up an optical image of the object to produce a picture signal while activated. A processing unit (21) processes the picture signal into a processed signal representative of the distance information. The optical beam may have an intensity which is higher that that of environmental light of the object. The predetermined time duration may be an instantaneous time duration. The beam generator may generate a flash of light as the optical beam. Alternatively, the beam generator may comprise a light source for generating a white light as the optical beam and a light source shutter for supplying the white light to the diffraction grating only when the light source shutter is activated. As a further alternative, the image pickup device may comprise a television camera and a pickup shutter for supplying the optical image of the object of the camera only when the pickup shutter is activated.
An automatic brake shoe measuring apparatus for rolling stock automatically measures the thickness of brake shoes of a vehicle and automatically detecting the presence or absence of damage during travel. The automatic measuring apparatus includes: a camera unit including a monitor camera for photographing brake shoes of a vehicle during travel and outputting an image signal, an image memory for storing the image signal, and a trigger detector for outputting a trigger signal to thereby store an image signal representing an image of a specific brake shoe of the vehicle; and an image processing unit including an extraction means for extracting the specific brake shoe in accordance with the image signal stored in the image memory and transferred from the camera unit, an arithmetic means for calculating the thickness of the specific brake shoe extracted by the extraction means, and a display means for displaying the thickness of the specific brake shoe calculated out by the arithmetic means.
A method and system for determining range by correlating a relationship between one or more distances of a diffraction grating from an illuminated target surface with variations in the respective wavelengths of high order diffraction spectra. The high order diffraction spectra are observed through the diffraction grating. The high order diffraction spectra are derived from broadband radiation transmitted from the illuminated target surface.
A relative visibility measuring process measures and stores a reference propagation time of a measurement pulse over a reference distance between a pulse propagation time rangefinder and a reflector under ideal conditions. A reference amplitude of a measurement pulse, which is reflected by the reflector under ideal conditions, is measured and stored. An actual signal which is equal to the time response of the received signals of the rangefinder under actual conditions, is measured and stored. A determination is made of an actual amplitude which is equal to the amplitude of a time element of the actual signal having a propagation time equal to the reference propagation time. A determination is made of the ratio of the actual amplitude to the reference amplitude and comparison of the ratio with a threshold value which is dependent on the visibility to be determined. A comparison is made between the signal waveform of the actual signal with standard waveforms for various visibility states of the measurement path. The comparison results are logically linked in order to produce a switching and/or warning signal to indicate a visibility undershoot or a measurement disturbance.
The present invention relates generally to an optical element (OE) which can serve as an optical analogue to digital converter (OADC) and/or an optical digital to analogue converter (ODAC), and uses therefor. The OE can be usefully employed in a variety of applications to transform analogue information present in a light wave front into digital light signals and/or to transform digital information into analogue information in the form of the physical parameters of a light wave front.
