Abstract: In a micro-dimensional measurement apparatus including an optical scanning system and a processor for optical data obtained therefrom, the measurement is based upon a comparison of previously prepared reference data and optical data obtained from an object to be measured. The comparison is carried out by using at least two kinds of optical data.

Abstract: An apparatus for measuring the profile of portions of an article located within a predefined plane. Each portion is scanned, such as by an optical micrometer providing a beam of radiant energy, to determine its dimension. The distance between each portion and a vertical reference is also scanned to determine its dimension. The article is rotated about an axis intersecting the predefined plane within the scan of the beam and is axially moved along an axis parallel to the intersecting axis within the scan of the beam so that the dimension of each portion and its distance from the vertical reference can be determined. The apparatus may be used in combination with a cavity identification system to control manufacturing employing multiple molds.

Abstract: A particle detection on a periodic patterned surface is achieved in a method and apparatus using a single light beam scanning at a shallow angle over the surface. The surface contains a plurality of identical die with streets between die. The beam scans parallel to a street direction, while a light collection system collects light scattered from the surface with a constant solid angle. The position of the collection system as well as the polarization of the light beam and collected scattered light may be arranged to maximize the particle signal compared to the pattern signal. A detector produces an electrical signal corresponding to the intensity of scattered light that is colelcted. A processor constructs templates from the electrical signal corresponding to individual die and compares the templates to identify particles. A reference template is constantly updated so that comparisons are between adjacent die.

Abstract: A laser-beam, pattern drawing/inspecting apparatus comprises a reciprocating stage for supporting a printed substrate having an etchant-resistant resist layer coated on it, a laser-beam scanning device having a laser for selectively emitting a first laser beam and a second laser beam less intense than the first laser beam, and an optical system for guiding the first and second laser beams to the printed substrate along the same optical path, the first laser beam scanning the resist layer to draw a pattern thereon, and the second laser beam scanning the resist layer, and a pattern inspection device for receiving the second laser beam reflected from the resist layer, thereby to optically inspect the pattern drawn on the resist layer.

Abstract: In the inspection of cylindrical objects, particularly O-rings, the object is translated through a field of view and a linear light trace is projected on its surface. An image of the light trace is projected on a mask, which has a size and shape corresponding to the size and shape which the image would have if the surface of the object were perfect. If there is a defect, light will pass the mask and be sensed by a detector positioned behind the mask. Preferably, two masks and associated detectors are used, one mask being convex to pass light when the light trace falls on a projection from the surface and the other concave, to pass light when the light trace falls on a depression in the surface. The light trace may be either dynamic, formed by a scanned laser beam, or static, formed by such a beam focussed by a cylindrical lens. Means are provided to automatically keep the illuminating receiving systems properly aligned.

Abstract: A photomask comprises a tested pattern (P.sub.1, P.sub.2) and a synchronization pattern (SP.sub.1 .about.SP.sub.8). The synchronization pattern is used for synchronizing a scanning signal (S.sub.9), obtained from the tested pattern, with a reference signal (S.sub.10), based on a reference pattern data stored on a magnetic tape (7).

Abstract: The present invention includes a surface inspection system with a single light source producing two light stripe sheets projected from different angles onto an inspected surface so that a combined light sheet produces a light stripe image with no shadows results. The two light stripe sheets are created by tangentially reflecting a laser beam off of separate cylindrical reflectors. The light stripe is detected by an imaging system, including a camera having a CCD image array, held at a fixed angle with respect to the light sheet which allows the two-dimensional curvature of the stripe to be detected. The two-dimensional light stripe image is converted into a digital image and processed by linear and logical digital filters that narrow the stripe down to two pixels wide. A coordinate extraction apparatus extracts the coordinates of the bottom row of the pixel image producing a digital representation of the light stripe curve.

Abstract: The invention provides a novel system for imaging a component lead on an assembled printed circuit board. The system incorporates a light source for illuminating a substantial portion of a solder pad of the circuit board being inspected. A photoreceptor receives emissions reflected from the illuminated portion of said solder pad and generates an image representative thereof. This photoreceptor is arranged so that passage of a component lead through the component hole occludes or shadows a portion of the solder pad from which the photoreceptor would otherwise receive reflected emissions. The system has application in the testing of printed circuit boards prior to wave soldering.

Abstract: To produce a standard calibration and test element for the calibration and testing of reading and measuring instruments for bar codes and other test scales, a copper coating is applied to a ceramic substrate in a chemically depositing copper bath and degreased, and a photoresist coating is subsequently applied which is exposed through an exposure mask. This mask carries an image of the radiation-transparent and radiation-opaque regions of a pattern to be transferred onto the surface of the ceramic substrate. After removal of the mask, the photoresist coating is developed, the uncovered zones of the copper coating are etched in a metal chloride solution, and the remaining photoresist coating is removed by stripping. The uncovered, etched zones of the copper coating are dyed matt black in a metal bath. Finally, the conductive tracks are provided with a protective coating.

Abstract: An inspection system for automatically documenting and verifying the position and dimensions of holes in a flat sheet metal workpiece. The system includes a transparent, light diffusing inspection table upon which the workpiece is laid. A ball screw-driven yoke travels continuously along the inspection table in the Y direction and includes a bottom bar for positioning a source of illumination below the table and a top bar for positioning a plurality of optical sensor arrays above the table. The optical sensor arrays are responsive to the presence (or absence) of light energy which is diffused by the table. A detector is interconnected to the sensor arrays to detect light-to-dark and dark-to-light transitions which are representative of the edge of a hole. The transition data is read and stored in a microcomputer for subsequent display and/or print out.

Abstract: A pattern detecting apparatus for inspecting a printed wiring board is disclosed in which a fluorescent image formed by the fluorescent light from the substrate of the printed wiring board and an image formed by the reflected light from the wiring pattern of the printed wiring board are both used because a wiring material which is left on an undesired portion of the substrate and has low reflectivity, is detected only at the fluorescent image and a defective portion of the wiring pattern where a surface layer thereof peels off, is detected only at the image formed by the reflected light, the image used for detecting the above defective portion is preferably formed by the reflected infrared light from the wiring pattern for the reason that infrared light is insensitive to a shallow flaw in the surface of the wiring pattern, and the fluorescent image and the infrared image are processed by a detection circuit, and then compared with each other to detect a pattern defect on the basis of a difference between the

Abstract: A device employing the optical autocorrelation method for automatically comparing the fingerprint of an individual with a previously identified exemplar utilizes a pair of multifaceted mirrors rotating about mutually perpendicular axes to sweep an image of the fingerprint over the surface of the exemplar in a raster. To maintain the image in focus, a pair of independent identical relay lens systems are positioned in the light path and arranged symmetrically with respect to a common intermediate image plane. The mirrors are positioned so that as they rotate their reflective facets coincide successively with the aperture stop locations of the respective lens system. To compensate for possible angular misalignment of the fingerprint and the exemplar, novel independent optical means are provided for effectively rotating the image about the principal axis of the light path.

Abstract: An optoelectric comparison apparatus for structures on plane surfaces or for planar structures has a laser light source 35 the operational light beam of which is split into two component beams 21, 22 by an optical displacement device 26, 25 for laterally displacing part of a beam. These two component light beams 21, 22 impinge on the mirror surfaces of a mirror wheel 11 obliquely to the axis of rotation 20. Two mutually crossed flat first strip mirrors 12, 13 are arranged in the direction of the light reflected from the mirror wheel 11 and each receive only one of the emergent component light beams 14, 15. The emergent component light beams 14, 15 are deflected in substantially opposite directions where, in each case, a further plane second strip mirror 16, 17 is provided which reflects the light to the scanning surface parallel to the light beams 14, 15 which enter into the first strip mirrors 12, 13.

Abstract: The invention relates to a method and an apparatus for calibrating a positioning system, including control means (209) sending command signals to the positioning apparatus (204) intended during a working state to locate an object (203) in relation to an operating area (206), the situation of the apparatus being sensed and converted to an actual value signal which is sent to the control means. The positioning apparatus has a working state which is interrupted at given intervals by a calibrating state, during which the positioning apparatus is accurately put in register with at least one detector (208), situated within the operating area in a given position. The output signals from the detectors are allowed to activate the control means, whereafter the actual value signal is determined and the positioning apparatus calibrated in response to the determined actual value signal.

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: An apparatus and method are shown for inspecting the externally threaded surface of an object such as a pipe. A video camera is mounted in a translational frame for movement in x,y,z planes. The translational frame is mounted in a rotational assembly which rotates the frame about the circumference of the pipe threads to be inspected. The video signals from the camera are digitized and sent to a computer processor where the signals are interpreted to position the camera as it moves linearly along the axis of the pipe threads and to detect defects and discontinuities in the threaded surface of the pipe being inspected.

Abstract: A mask inspection apparatus is arranged to compare a measured data signal obtained by optically measuring a photomask with a design data signal representing an integrated circuit pattern so as to inspect defects of the photomask on which the integrated circuit pattern is drawn. To inspect the pattern area and its peripheral area of the mask in one step, a reference signal generator in the mask inspection apparatus is arranged to generate a reference signal containing a predetermined additional data signal representing the peripheral area of the integrated circuit pattern, in addition to the design data signal representing the integrated circuit pattern. The reference signal is compared with the measured data signal of the pattern area and its peripheral area.

Abstract: A method and apparatus of measurement and/or dimensional comparison.

Abstract: Apparatus 20 for inspecting photomasks 26 and the like by comparison of duplicate die patterns, including improved defect detection. Two-dimensional pixel representations of two die patterns are formed, with pixels having values or black or white or shades or grey, depending upon the features of the die patterns. Defects in the die patterns are found by a defect detector circuit 60 at points of non-agreement between the pixel representations. Two window matrices 130 and 134 of adjacent pixels are defined for corresponding areas of the two die patterns. The center matrix of each window matrix is defined as a comparison matrix 132 and 136. An error value is computed for subsets of the window matrix by summing the squares of the differences between each of the pixel values of each subset and the corresponding pixel values of the opposite comparison matrix. If there is no defect and any misalignment between the two representations minimal, at least one error value will be less than a threshold error value.

Abstract: An automatic printed wiring board (PWB) defect detector is described. The detector comprises an array of optical sensors for optically inspecting a printed wire circuit. The array forms a binary image pattern of the PWB which is tested for compliance with logical rules of correctly printed PWB's regarding unterminated conductors; minimum specified lined width; line spacing width; presence of insulators on conductors and vice versa; and maximum line width. The detector comprises a plurality of CCD arrays arranged to form a series of pixels consisting of electronic binary signals corresponding to the instantaneous image viewed by each element in the CCD array. These pixels are formed in an image data stream of sequential pixels line-by-line of the CCD array, i.e., pixel sequential line sequential digital image data. The digital pixel data is formatted in an "N" by "N" bit matrix of points in proper image orientation. All such points are available for sampling.

Abstract: A method and an apparatus for detecting a flaw on threads of a male screw, which comprises: fully applying a light from a light source onto tops, roots and flanks of threads of a male screw while rotating the male screw around the axis thereof; continuously measuring, by means of a photoelectric converter, electric signal values corresponding to variations in brightness of the male screw in the axial direction thereof during one turn of the male screw around the axis thereof; moving-averaging the thus measured electric signal values corresponding to the variations in brightness of the male screw in the axial direction thereof; determining electric signal values corresponding to variations in brightness of the male screw in the circumferential direction thereof, on the basis of the thus moving-averaged electric signal values corresponding to the variations in brightness of the male screw in the axial direction thereof; obtaining a mean square value of the thus determined electric signal values corresponding to

Abstract: In a pellet pattern recognition method, a pellet pattern recognition apparatus is used which includes a table for determining a pellet pick-up priority order, pellet memory table for storing data of good and bad pellets as well as data representing an "already picked-up" state and a "not picked-up" state, and position memory table for storing a positional shift of each of the good pellets within a pellet pattern recognition range away from the picked-up pellet. When the good pellets are to be sequentially picked up, the shape identification and position detection of the pellets within the pellet pattern recognition range are effected by calculating the correlation coefficients. In this case, calculation is performed with respect to the pellet array on the basis of the results of the shape identification and position detection and initially set reference data, and the good pellet is stored, as the corresponding coordinate data, in the pellet memory table.

Abstract: In a surface inspection method in which parallel rays passing through a thin slit are projected onto a surface of a specimen and a luminous line formed on the specimen surface by the parallel rays is viewed by a television camera so as to inspect the specimen surface, a photo-electric signal showing the luminous line is picked up from an output video signal of the television camera. The time from rising state of the horizontal synchronizing signal contained in the video signal to occurrence of a pulse of the photo-electric signal is measured in each period of the horizontal synchronizing signal. The time data in each period is compared with a previously set reference value, and whether or not the specimen passes the inspection is discriminated based on variation of the comparison result.

Abstract: A method for measuring the transverse profile of the head of a rail of a railroad track according to which a luminous trace (1) is projected onto the surface of the head of a rail, in a direction perpendicular to the longitudinal axis of said rail, this trace (1) having a particular point (3). The trace obtained is observed from two directions forming an angle (.alpha.) between them, located on either side of a longitudinal plane of the rail (2) and forming an angle with the plan of projection of the trace. This observation creates two partial reproductions (1'; 1") of this trace (1). Finally the two partial representations (1', 1") are angularly displaced by an angle corresponding to the angles from which the trace is observed and the images (3', 3") of the particular point (3) of the trace (1) are superimposed to obtain the representation of the transverse profile of the rail in its totality.

Abstract: Apparatus and method for processing fruit and the like, particularly for sorting as a function of variables including color, blemish, size and shape. The apparatus provides an illuminator for substantially uniformly illuminating a portion of the item being examined, and a signal detector array for generating a plurality of signals corresponding to respective different portions of the item being examined. The data signals corresponding to a given item are accumulated and then batch processed to determine sorting signals, while a next item is being examined and data signals for it are being accumulated. For blemish detection, the batch processing includes determination of differences between signals representing adjacent surface portions, and generation of blemish sorting signals as a function of such determined differences.

Abstract: An automatic printed wiring (or circuit) board (PWB) method for detecting maximum line width violations is described. The method utilizes an array of optical sensors for optically inspecting a printed wire circuit. The array forms a binary image pattern of the PWB which is tested for compliance with logical rules of correctly printed PWB's regarding maximum line width. The detector comprises a plurality of CCD arrays arranged to form a series of pixels consisting of electronic binary signals corresponding to the instantaneous image viewed by each element in the CCD array. These pixels are formed in an image data stream of sequential pixels line-by-line of the CCD array, i.e., pixel sequential line sequential digital image data. The digital pixel data is formatted in an "N" by "N" bit matrix of points in proper image orientation. All such points are available for sampling. Each pixel progressively occupies each point in the matrix in proper orientation to its neighbors.

Abstract: An automated inspection station comprises a pair of rotating rollers for supporting a collected group of pellets. A pusher drops in behind the group to urge the entire group forward. The rotating rollers cause the entire group of pellets to spin in unison as the pellets pass through an optical inspection station. The optical inspection station comprises a light source, diverging and collimating lenses to illuminate each rotating pellet in turn. Signals are generated by at least two arrays of photodiodes in response to light reflected from the surface of the pellets. Circuitry normalizes the signals of the respective diodes for variations unrelated to pellet surface features. The signals are analyzed to ascertain conformance of each pellet to length, cylindricality diameter and surface reflectivity requirements. A pellet sorter diverts unacceptable pellets from the path, while the acceptable pellets are transported to a collection station.

Abstract: Disclosed is a shape detecting apparatus comprising a slit projector for projecting a slit bright line on a number of objects arrayed in a line, an image forming lens for forming the bright line image, an image scanning mechanism for the bright line image formed through the image forming lens in a height direction of the object and a one-dimensional image sensing device for self-scanning the bright line image formed therein with an array of image sensing elements orthogonal to the scanning direction by the image scanning mechanism.

Abstract: A video blink comparator incorporates an optical system for presenting and superimposing a data pattern image and reference pattern image, a video system for generating a video signal for final comparison of the reference image and data image, and a control system for blinking the respective data image and reference image on and off at the same frequency and out of phase so that a video picture formed by the video signal remains constant when the data image and reference image patterns are substantially identical and so that variant elements of the respective patterns blink on and off in the video picture. A lens system is provided spaced from a video camera to provide variable magnification or enlargement of the superimposed pattern images. Universal mounting of components permits sequential scanning of the superimposed image in fractional portions or blocks permitting non-linear distortion introduced during pattern formation.

Abstract: A method of and apparatus for inspecting the machined accuracy of a contour in a workpiece, e.g. machined by wire-cutting EDM, to form a desired contour therein make use of a light beam focused on a focal area on the workpiece and an optical lens and mirror system for projecting an optical image of the machined contour upon magnification on a display screen having predetermined indicia. The workpiece is positioned to locate a portion of the machined contour in the focal area in a predetermined X-Y coordinate system. A table carrying the workpiece is displaced by motors in response to drive signals furnished from an NC unit to displace the workpiece in the X-Y coordinate system so that the focal area effectively moves on the workpiece along a path of the desired contour and the light beam focussed thereon scans the machined contour.

Abstract: Workpiece identification apparatus for use in identifying to which of a number of predetermined types a workpiece belongs. The apparatus scans workpieces to be learnt and calculates a set of parameters of each workpiece. After scanning all the workpieces to be learnt, the apparatus selects a sub-set of the parameters such that the sub-set is unique for each learnt workpiece with an allowance for a selected number of parameters to be erroneously determined. The apparatus then scans workpieces to be identified and calculates an equivalent sub-set of parameters thereof and identifies the workpiece by comparing this sub-set with the learnt sub-sets.

Abstract: Optical inspection apparatus for detecting differences between two dies in a photomask and including a carriage for supporting the objects to be inspected and for simultaneously moving such objects along an inspection path, an illuminator for illuminating corresponding portions of the objects as they are moved along the inspection path, electro-optical detectors for individually inspecting the illuminated portions and for developing first and second electrical signals respectively corresponding thereto, electronic memories for storing the first and second electrical signals, a computer for scanning the memories and for electronically aligning a readout of the first signal relative to a readout of the second signal, and a comparator for comparing the electronically aligned signals and for indicating any differences therebetween.

Abstract: Method and apparatus for inspecting threaded objects and for determining the depth of blind holes. For inspecting threads, a light source is provided for illuminating threads of a threaded object. A lens forms an image of the illuminated threads. A detector having a light sensitive area sufficiently small to resolve the thread image is provided to detect the image and an output signal is produced in response to the incident image light. The output signal is analyzed to determine the quality of the threads. For determining the depth of a blind hole, a light source forms a spot on the bottom of a blind hole in an object and the lens forms an image of the spot. Means are provided to detect the spot image to produce an output signal responsive to the incident image light. Means are provided to analyze the output signal to determine hole depth.

Abstract: An apparatus for measuring contour configuration of articles, particularly brittle articles such as ceramic honeycombs without touching them comprising a turn table on which the article to be measured is placed, a rotary encoder mechanically coupled to the turn table for producing a rotational angle signal representing a rotational position of the article on the turn table, an edge detector including a parallel light projecting member and a parallel light receiving member, those members being arranged on respective sides of the turn table in such a manner that a part of the parallel light is shielded or cut by the article and an edge position signal is produced, a memory for storing a standard edge position signal which will be produced by the edge detector when a standard article having given dimensions placed on the turn table is scanned during a single rotation thereof, and an operation circuit for receiving the rotational angle signal from the rotary encoder, the edge position signal from the edge detecto

Abstract: An apparatus for measuring contour configuration of articles, particularly brittle articles such as ceramic honeycombs without touching them comprising a turn table on which the article to be measured is placed, a rotary encoder mechanically coupled to the turn table for producing a rotational angle signal representing a rotational position of the article on the turn table, a lamp for illuminating the article on the table, particularly a portion of article to be measured such as an upper edge or side edge, a pick-up device including a lens for forming an optical image of said portion of article and an image detector such as a linear array of image sensor for converting the optical image into a picture signal, a memory for storing a standard picture signal which will be produced by the image detector when a standard article having given dimensions placed on the turn table is scanned during a single rotation thereof, and an operation circuit for receiving the rotational angle signal from the rotary encoder, the

Abstract: Optical inspection apparatus for detecting differences between two dies in a photomask and including a carriage for supporting the objects to be inspected and for simultaneously moving such objects along an inspection path, an illuminator for illuminating corresponding portions of the objects as they are moved along the inspection path, electro-optical detectors for individually inspecting the illuminated portions and for developing first and second electrical signals respectively corresponding thereto, electronic memories for storing the first and second electrical signals, a computer for scanning the memories and for electronically aligning a readout of the first signal relative to a readout of the second signal, and a comparator for comparing the electronically aligned signals and for indicating any differences therebetween.

Abstract: An automatic printed circuit board tester in which a laser beam is directed onto and scanned around solder pads and foil regions of a printed circuit board, and errors in structure are determined by detecting patterns of scattered light and comparing these patterns with similarly obtained ones from a properly constructed board.

Abstract: A device for indicating the fibre length distribution of a fibre sample for use with an apparatus which produces output signals representative of the number of fibres in a cross section of a fibre sample by slit-wise illumination of the sample, has a pulse generator to produce a pulse stream representative of the relative positions of the sample and illuminating beam, comparators to compare signals received by opto-electric converter with reference signals to stop counters driven by the pulse stream when predetermined values of the received signals are reached and an indicator for the contents of the counters. The reference signals are derived from the received light signals at predetermined relative positions of the sample and beams.

Abstract: An apparatus for detecting defects in patterns, particularly defects in chip patterns of photomasks for use in manufacturing semiconductor integrated circuits comprising optically scanning means for scanning in a raster scan mode identical portions of the two patterns to be compared with each other by means of a pair of lens systems to produce a pair of picture signals each corresponding to a respective one of the scanned pattern portions and a defect signal producing means for receiving said pair of picture signals and producing a defect signal as a difference between the two picture signals. A variable delay circuit is provided between the optically scanning means and defect signal producing means to correct or compensate for deviations in the two picture signals due to differences in optical characteristics between the two lens system such as distortion and magnification. The variable delay circuit delays the picture signals for a delay time which is varied as a function of a position on the raster.

Abstract: An apparatus for detecting defects in patterns, particularly defects in chip patterns of photomasks for use in manufacturing semiconductor integrated circuits comprising an optically scanning means for scanning identical portions of the two patterns to be compared with each other with a pair of scanning light spots to produce a pair of picture signals each corresponding to a respective one of the scanned pattern portions; and a defect detecting section for receiving said pair of picture signals and producing a defect signal as a difference between the two picture signals.

Abstract: This invention relates to the classification of a stream of documents, such as mixed mail pieces, into size and orientation of categories for subsequent processing. The apparatus includes a laser beam which scans a conveying belt upon which the documents are placed. Appropriate circuitry is provided so that a determination may be made as to the length and width of the document being conveyed across the belt. Downstream from the belt is a segregation system in which the various sizes of documents are segregated according to size in response to the determination of the circuitry.

Abstract: An electro-optical inspection system for a binary patterned web which automatically determines registration and the quality of subjects of inspection by comparison with a master pattern stored in the memory of a computer and then passes or rejects individual subjects of inspection depending on the outcome of the comparison effected.

Abstract: Disclosed apparatus sort unequally dimensioned veneer sections or other objects which are successively conveyed in a transit direction by a conveyor in parallel to their planes. A series of sensors are mounted at equal mutual distances across the conveyor in a row extending transversely to the transit direction and generate sensor signals in response to successively conveyed objects. The sensor signals are analyzed and the extents of the conveyed objects are tested on the basis of the analyzed sensor signals, preferably with the aid of predetermined nominal values. The conveyed objects are sorted in accordance with their tested extents.

Abstract: A motor speed control system for reducing instantaneous speed variations as a result of hunting in hysteresis synchronous motors utilized to drive optical scanners by controlling the frequency of the drive signal applied to the motor. A laser beam is reflected from the facets of the optical scanner and scans a surface along a scan line, a signal being generated at the start and end of each scan line. A counter is driven by an accurate clock which is started and stopped in accordance with the start and end of scan signals. The resulting count of the counter is thus inversely proportional to the speed of the motor and is converted to an analog input signal and coupled to a voltage controlled oscillator whose frequency is controlled for driving the motor such that undesirable oscillations of the motor are damped out. Additional embodiments for controlling the motor speed are disclosed which utilize only the start of scan signal to both start and stop the counter.

Abstract: An automatic system for scanning a generally cylindrical member with a thin beam of light. Detectors are provided for sensing interruption or scattering of the light beam by inclusions within the member. When an inclusion is detected transverse scanning stops and the beam is fixed along a chord of the cylinder. The cylinder is then rotated to cause the inclusion to intercept the chordal beam, and the information thus generated is used to identify the type and position of inclusions within the blank.

Abstract: Disclosed is apparatus for sorting objects, e.g. tomatoes, according to both size and color. A preferred embodiment can sort the objects into fourteen size/color categories and yet requires only two photodetectors. The objects travel on a conveyor belt past a sensing station having a light source to illuminate an object and a pair of phototransistors for receiving light reflected from the object in two different color bands, e.g. red and green. The phototransistors produce a pair of output electrical signals. An analog divider forms a ratio of the electrical signals and the peak value is stored and compared with preset limits to produce a color category signal. A size category signal is derived on the basis of the time duration of the signal produced by the summation of the phototransistors' signals.