Abstract: A comparison-type dimension measurement system in which a laser 1 provides linearly polarized light that is directed by a polarization beam splitter 5 into a microscope system in which a specimen 13 is mounted. The reflected polarized light is rotated 90.degree. by a quarter wave plate 9 and passes through the beam splitter to a multi-element line sensor 19. The laser light is scanned by a rotatable mirror 3 over the specimen. Threshold intensities are determined on indicia of known separation on a reference specimen and used to calibrate the distance measured by the line sensor.

Abstract: Luminescent security features in or on documents are detected using a detector comprising a fibre optic light guide arranged to transmit an interrogation beam originating from a source onto a document to be tested; and a housing in which a photo-diode array is mounted to receive luminescence emitted from the document. The photo-diode array is connected to electronic circuitry for discriminating between luminescence due to a security feature and other luminescence emitted by the document and for determining that a security feature has been detected.

Abstract: Multichannel electrophoresis apparatus employing electrophoretic light scattering as a means for characterizing the particles under study. The apparatus is characterized by the ability to measure light scattered simultaneously using a plurality of local oscillators incident at different angles from the same population of particles being subjected to electrophoresis. The apparatus is used with data processing means to analyze the large amount of scattering data which provide information on electrophoretic mobility, particle size, particle charge, electrophoretic mobility, zeta potential. An important aspect of the new apparatus is a markedly improved capability to segregate data related to diffusion effects from data relating to heterogeneous effects.

Abstract: The invention provides an optical measuring apparatus in which an object to be measured is scanned by parallel measuring rays, the length of the object being measured from changes of intensity of the measuring rays. The received rays are utilized as start and stop signals from a counter for counting clock pulses. The measuring rays are emitted from a laser and reflected by a rotating mirror to scan the object. When the measuring rays are blocked by the object, the counting operation of the counter is initiated. As the rays again appear from behind the object, the counting operation is stopped. The number of clock pulses counted between the start and stop of the counting operation is used to measure the length of the object. Any error induced from deflection or scattering of the measuring rays at the end faces of the object or from the transparent part of the object can be avoided by providing a register for latching the output of the counter.

Abstract: A headlamp testing method of the invention involves the steps of applying the low beam of the headlamp onto a screen, determining the position of the geometrical center of a closed area of illuminance higher than a predetermined level, determining the position of a cut off line cross point from the position of the geometrical center and a predetermined amount of offset, and determining a presumption line cut off line from the cut off line cross point. The presumption line thus determined is displayed together with a mark which indicates the within which the cross point should fall, and the headlamp beam is judged as being acceptable when the cross point is located within this range.

Abstract: The optical measuring instrument emits a coherent beam of radiation normally to a surface of an object. The scattered radiation generated by the beam of radiation is guided through an optical device to a stationary strip-shaped linear radiation sensor element. The linear radiation sensor element is arranged within a hollow cylinder which is rotatable in an operative position thereof. The hollow cylinder contains a multiple number of slots which traverse the strip-shaped linear radiation sensor element at an acute angle. An evaluation circuit arrangement is connected to the linear radiation sensor element and only generates evaluatable measuring signals during the traversal of one of the slots over a location at the linear radiation sensor element where there occurs a radiation intensity exceeding a predetermined threshold value. Using such measuring instrument it is possible to measure distances with high resolution.

Abstract: Surface inhomogeneities of a piece of glass are detected by disposing the glass piece in interfacial relation to an optical medium and reflecting light at a predetermined angle of incidence from the glass surface - optical medium interface along a scan path, through at least a portion of the optical medium. The optical medium is selected to have a refractive index equal to the bulk refractive index of the piece of glass. The intensity of the light reflected from the glass along the scan path is monitored to indicate surface inhomogeneities and the location thereof on the glass surface.

Abstract: A method and apparatus for discriminating a surface of a developed film focuses a picture pattern on a film disposed at a reference position. One or two sensors are then located at focused positions of the picture pattern of the film when the front surface of the film is at the reference position and when the back surface of the film is at the reference position, respectively. The two resultant sensor outputs are then band-pass filtered to extract the portions of the outputs within a predetermined frequency range. The resultant outputs are then rectified and integrated and then compared by a comparator whose outputs is a first value when the front surface of the film is at the reference position and is a second different value when the back surface of the film is at a reference position.

Abstract: A three-dimensional triangulation-type sensor-illumination system adapted for connection to a machine vision computer. The illumination source in the preferred system comprises a unique cross hair light pattern which provides sufficient image data to the computer to enable the computer to make three-dimensional measurements of a wide variety of features, including edges, corners, holes, studs, designated portions of a surface and intersections of surfaces. The illumination source and sensor are both mounted within a single housing in a specific position and orientation relative to one another, thereby permitting the system to be internally calibrated. In addition, the sensor-illuminator unit is preferably mounted in a test fixture so that the light source is substantially normal to the surface of the part to be examined and the sensor is thereby positioned at a perspective angle relative thereto.

Abstract: An improved method of measuring film thickness of the film layer on a certain material is disclosed. The method is carried out by way of the steps of measuring reflection intensity spectrum, determining extreme values of wavelength relative to the spectrum, preparing an expected value table relative to the reflection interference orders associated with the extreme values of wavelength, calculating a group of expected values of film thickness with reference to the expected value table, calculating deviated values among the values of film thickness in association with the group of expected values, determining the expected orders which minimize absolute values corresponding to deviated values as true interference orders and determining a required film thickness with reference to the thus determined interference orders.

Abstract: Three-dimensional surface measurements are made in the presence of interfering background light such as weld arc glare by scanning the surface with a narrow light beam and synchronously masking the image of the illuminated surface to block all light within the area of expected light returned by the surface from the scanned light beam. The masking is moved synchronously across the image area as the expected returned light follows the scanned path of the scanning light beam. Masking is accomplished mechanically or by electro-optic devices.

Abstract: The invention relates to measuring illuminating power of light incident on a light sensor without an outside power supply. The light is converted conventionally to a pulse train, the frequency of which varies as the illuminating power. During conversion the incident light illuminates a series connection (2) of a plurality of photo diodes, which thus generate a current. This is utilized as a power source for the converter and also as electrical input quantity for the conversion itself. The pulse train generated by the converter comprises light pulses, the frequency of which is detected at the converter or at the other end of an optical fibre (7) coupled to it.

Abstract: A particle analyzing apparatus has a flow cell provided with a flow section passing therethrough a particle to be examined, an irradiating system for irradiating the particle to be examined in the flow cell with an irradiation light beam having a predetermined light intensity distribution in a direction perpendicular to the direction of application, a photodetector for photometering the light from the particle to be examined irradiated by the irradiating system, a detector for detecting the information regarding the light intensity of the irradiation light beam of the irradiating system at the position of the particle to be examined, and a compensation part for correcting the output of the photodetector on the basis of the output of the information detector.

Abstract: The present invention relates to a method and apparatus for measuring the content of suspended substances in a flowing medium by illuminating the medium with light from a light source. Reflected light from the medium is detected by at least two detectors, at least one of which measures directly reflected light while the other detectors measure multiply reflected light. The detector for detecting directly reflected light is located such that a linear relationship is established between its output signal and the concentration of the flowing medium. The other detectors are located such that their output signals will be essentially constant in relation to the concentration of particles in the flowing medium within a large range. The measuring scheme provides for obtaining the quotient of the signal provided by direct reflection divided by the signal provided by multiple reflection.

Abstract: In an apparatus for measuring the optical characteristics of an optical system to be examined a light source determines a reference optical axis and generates a light beam that is passed through the optical system to be examined along the reference optical axis. A mask partly transmits the light beam therethrough and has a pattern comprising at least one straight line disposed off the reference optical axis in the light beam, the straight line of the pattern extending in a predetermined direction in a plane substantially orthogonal to the reference optical axis. A photosensitive detector receives the light beam passed through the optical system to be examined and the mask. The detector is fixedly disposed relative to the mask and has a substantial length in a direction substantially orthogonal to the reference optical axis and the straight line of the pattern.

Abstract: In aberration measurement, a light beam from a light source provided at the image plane position of a lens to be examined is caused to enter the lens to be examined, the light beam passed through the lens to be examined, is separated into a plurality of light rays in a plane perpendicular to a principal ray or in a plane perpendicular to the optical axis of the lens to be examined, and the position of each light beam is detected at a position which is spaced apart from a position optically conjugate with said image plane position with respect to the lens to be examined and at which the plurality of light rays can be separated from one another.

Abstract: A method for the stereophotogrammetric survey of a large-dimension object is provided in which the object and a chain having two reference markers thereon spaced apart at a known distance are photographed from a height of about 30 m with two synchronized metric photographic cameras spaced apart by about 6 m. Depth measurements (Z axis) are made on a stereoscopic model reproduced by a stereoplotter at eight sets of points grouped in the eight conventional perimetral locations of photogrammetric orientation at the crests and troughs of the ripples or undulations of the water or ground, respectively. The mean of the depth measurements is calculated to determine the mean horizontal plane and the model is correctly orientated with respect to the horizontal plane by suitable rotation.

Abstract: A refractometer comprises a light source, an angle prism and an optical system in a casing so mounted that the optical system focuses an image of a diaphragm at said light source upon a double photodiode located beyond the prism and supported by an oblique surface of the casing. The ratio of the output of one photodiode to the output of the double photodiode is measured to register the index of refraction.

Abstract: An apparatus which comprises a collimating lens, light source means for selectively forming light sources in two positions on the optical axis of the collimating lens, means for defining the position of the lens to be inspected opposite to the light source with respect to the collimating lens, a mask plate having translucent or opaque areas symmetrical to the optical axis, a relay lens for placing the mask plate at a position conjugate with the lens position, an imaging lens positioned opposite to the mask plate with respect to the relay lens, and photoelectric converting means for producing image signals corresponding to the positions, in a plane perpendicular to the optical axis, of the image of the translucent or opaque areas of the mask plate formed by the imaging lens.

Abstract: A pattern of light is projected upon a surface to be measured which may be devoid of surface detail. A sharply focused image of the surface provides distance discrimination. Although the projected pattern may be separate from the imaging optics, a common optics path removes distortion, provides maximum sensitivity and eliminates processing for misalignment between projector and imager. Parallel detection of regions within the image receiving light intensities above a threshold enables rapid availability of measurements. Optical cross-correlation and Fourier transform processing methods may be employed to enhance image processing with no processing delay. Three-dimensional co-ordinate measurements relative to the sensor are reported for all in-focus regions of the image. Refocusing the lens provides depth coverage.