Abstract: An automated sorter includes a feed slide on which containers or refuse may be fed. The feed slide includes a separation region on which a several objects may be located. A light source directs light on the objects in the separation region. An ejector, including several ejector units, is positioned downward of the separation region. A scanner scans the separation region, determines when an object should be ejected, and controls the ejector units to eject the selected objects. Thus, the selected objects are ejected into a first fraction, and the non-selected objects are left in a second fraction. A fraction thus obtained can be sorted, to separate the containers or refuse into further fractions.

Abstract: A method and apparatus for separating pieces of wood into different qualities in a wood sorting process is characterized in that the brightness as well as the texture of the surface of the wood are measured, and the pieces of wood are separated into different quality groups according to the measurements results obtained.

Abstract: A scrap particle sorting system and attendant sorting process employs a conveyor for conveying the randomly shaped particles in a random orientation, a position sensor for determining the advancement of the scrap particles in the direction of conveyance by determining the position of the conveyor belt, an image detector for periodically recording the image of a predefined viewing area through which the scrap particles are conveyed, and an image processor for periodic acquisition and processing of the images. The image processor includes logic for defining each image of the viewing area into a matrix of cells, and for each acquired image, analyzing the digital data corresponding to the image to determine for each cell in the matrix whether the pixels in that cell satisfy a predetermined criteria, and establishing a discriminator signal for each cell in the matrix as a function of that analysis.

Abstract: An electrophotographic printing machine of the type in which a leading edge and a trailing edge of a moving sheet are detected. The improvement includes an elongated light source that is of a length greater than that of an irregularity on the moving sheet. The elongated light source extends in a direction substantially parallel to the direction of the moving sheet. A plurality of sensors are arranged in an array and are movably mounted on a support which is extended in a direction substantially parallel to the elongated light source. The elongated light source is movably mounted to another support, so as to position the light source relative to the array of sensors. A lens, interposed between the light source and the sensor array focuses light rays emitted from the light source on to the sensors. The sensors are in a receiving relationship with the light source. The elongated light source and the array of sensors define a passageway through which the moving sheet passes.

Abstract: A system for monitoring contents of a tray located beneath a basket of a shopping cart as the latter is passed through an aisle adjacent a checkout station having a point of sale terminal capable of receiving a signal through a communications interface which signal prevents completion of a transaction unless overridden by operator input of one of a product and an override code. The system includes apparatus adjacent the aisle for detecting and signalling presence of the cart in the aisle, apparatus adjacent the aisle for scanning a space above the tray of the cart to detect and signal the presence of objects thereon, and apparatus responsive to signals from both said cart detection apparatus and the object detection apparatus to output said signal to the communications interface of the terminal, thereby forcing the operator to enter one of a product and an override code.

Abstract: Disclosed is a full container recognition system (5) for determining when a container (16) having an upwardly facing opening is filled with articles (18) to a predetermined level. The system includes at least one deflectable feeler arm (10) mounted to a support (22) so that an outer end (32) of the feeler arm extends over the opening of the container. As articles (18) are loaded into the container (16), the articles impact the outer end (32) of the feeler arm (10) causing the feeler arm to deflect downwardly from an up position in which the feeler arm is biased. When the article (18) passes downwardly beyond the outer end (32) of the feeler arm (10), the biasing arrangement causes the feeler arm to return to the up position.

Abstract: Document-imager for imaging documents (e.g. checks that are transported past an imaging-site, where the site is illuminated by one (or two) pairs of lamps symmetrically disposed about the site, with image-reflection sent back between lamps to be captured.

Abstract: A method and apparatus for detecting foreign matter in a particulate material stream, particularly tobacco, including an optical scanner, in combination with a camera system with beam splitter and filters, and a computer to process signals from the camera to determine whether foreign matter is present. If foreign matter is detected, a diverter deviates the flow of the contaminated material onto a discharge conveyor.

Abstract: A coin sensor device for determining the authenticity of a coin traveling along a predefined path including a first sensor device such as an optical sensor device located along the path, a second sensor device such as a second optical sensor device spaced a predetermined distance from the first sensor device along the path, the first and second sensor devices producing signal responses when a coin moves thereby, and a processing device connected to the first and second sensor devices for measuring two distinctive time intervals, the first time interval beginning when the trailing edge of the coin is sensed by the first sensor device and continuing until the trailing edge is sensed by the second sensor device, the second time interval beginning when the leading edge of the same coin is sensed by the second sensor device and continues until the trailing edge is sensed by the second sensor device, the processing device determining the ratio of the two time intervals and based on a determination of a predetermine

Abstract: A singulated stream of products comprised of both single and overlapping products is transported through a scanning zone along a transport path. Each single or overlapping product defines a shadow on the transport path that is analyzed to determine the presence of product multiples in the product shadow by measuring the width and length of the product shadow. If the length of the product shadow exceeds by more than a predetermined amount the average length of previously measured shadows having a similar width, the shadow likely contains two or more overlapping products. As the product shadow moves through the scanning zone, each product included therein is scanned for affixed bar codes by a plurality of bar code scanners. If two different bar codes or two identical bar codes from mutually exclusive scanners are recorded for a single product shadow, then the shadow likely contains two or more overlapping products.

Abstract: A system for registering boxes carried on one conveyor line with wraps carried on another conveyor line, in which the boxes and wraps are viewed by electronic cameras that provide respective digitized images of the boxes and wraps, and a computer determines from those images sufficient information to effect such registration by a mechanical arm that spots the boxes on the wraps regardless of their original orientation, responsively to commands from the computer. A vacuum plenum is disposed beneath the wrap conveyor for maintaining a negative pressure that releasably retains the wraps on a surface of the wrap conveyor. The wrap conveyor comprises a flexible, pneumatically porous, light-transmissive conveyor belt for moving the wraps for viewing by a camera against the upper surface of the belt, the belt being supported over the vacuum plenum on an apertured, light-transmissive frame.

Abstract: An image forming apparatus for forming an image on a recording medium includes a first sensor for detecting a supply of the recording medium, a second sensor for detecting the type of the recording medium and a third sensor for detecting the size of the recording medium. The image forming apparatus of the present invention automatically determines threshold values of first, second and third sensors by feeding the recording medium so as to adjust output levels of first, second and third sensors. The image forming apparatus may thereby print the image on the recording medium in accordance with the size and the type of the recording medium detected by the second and third sensors when the first sensor detects the supply of the recording medium.

Abstract: A pair of conveyor belts arranged to form a substantially V-shaped conveying path for slender, elongated tubular members of a predetermined length. A small gap is provided between the conveyor belts at the apex of the V-shaped conveyor assembly. A light transmitter directs a beam across one of the conveyor belts and into the gap toward a receiver. A member to be measured lies in the V-shaped groove periodically breaking the beam according to the length thereof. A pulse generator develops output pulses at a rate determined by the linear speed of the conveyor. First and second detectors count pulses at the initiation and determination of a detector beam to each determine a length. The length of the workpiece is determined by taking an average of the two values.

Abstract: A retail check stand device has a conveyor and a pair of side walls, each of the side walls further including a side wall section presenting an inner planar surface on a respective side of the conveyor to confine articles. One of the side wall sections has a cavity adjacent the planar surface. A sensing means is provided to sensing objects on the conveyor. An opening is formed in the side wall section to provide access to the cavity. A check stand controller is responsive to the sensing means and is arranged to fit through the opening and be located in the cavity.

Abstract: A method is provided for detecting a junction between adjacent can ends which are arranged in a stack. The method enables a selected number of can ends in the stack to be counted. The method comprises the steps of illuminating the peripheral edge regions of can ends in the stack with a signal emitted by a emitter inclined at an oblique angle to a line normal to the central axis of the stack and detecting reflected signals from the ends of the peripheral edge regions of the can ends. Oblique illumination provides alternating regions of the stack reflecting a relatively high and relatively low light intensity. Detection of the light intensity across the length of the stack enables a junction between adjacent can ends to be determined.

Abstract: Apparatus for testing the end portions of cigarettes to detect end portions containing insufficient quantities of tobacco has a conveyor which transports the cigarettes sideways past at least two testing stations each of which accommodates a discrete capacitive and/or photoelectronic testing unit. Repeated monitoring of the end portions of successive cigarettes reduces the likelihood that unsatisfactory cigarettes, particularly cigarettes with end portions which are empty or contain insufficient quantities of tobacco particles, would reach the consumers. Signals which are generated by the testing units can be used to segregate cigarettes having defective end portions.

Abstract: Cigarettes on a conveyor are surface checked, in at least one observation station, by means of at least one optical unit having a light source for directing light rays on to one half of the outer surface of the cigarette, and a pair of prismatic bodies facing respective quarters of the surface of the cigarette, and which provide for directing all the rays reflected from the aforementioned half of the surface into one beam directed towards one monitoring unit.

Abstract: For the measurement of the diameter of coins (1) or other circular objects, such coins or other objects pass the guide channel at substantially the same velocity. In a lateral wall of the guide channel, at least two photoelectric detectors (3, 4) are arranged at different heights which are obscured by such coins or other circular objects when passing the channel (FIG. 1 ).

Abstract: A singulated stream of products comprised of both single and overlapping products is transported through a scanning zone along a transport path. Each single or overlapping product defines a shadow on the transport path that is analyzed to determine the presence of product multiples in the product shadow by measuring the width and length of the product shadow. If the length of the product shadow exceeds by more than a predetermined amount the average length of previously measured shadows having a similar width, the shadow likely contains two or more overlapping products. As the product shadow moves through the scanning zone, each product included therein is scanned for affixed bar codes by a plurality of bar code scanners. If two different bar codes or two identical bar codes from mutually exclusive scanners are recorded for a single product shadow, then the shadow likely contains two or more overlapping products.

Abstract: A reflex proximity sensor includes a light emitting source which directs a beam by way of a beamsplitter toward a retroreflective surface, which reflects incident light back towards the source. A non-uniform (eccentric) convex lens is positioned in the beam path to produce a beam of light which is dispersed along a sensing axis, so that an eccentric cross-section beam is directed toward the retroreflective surface. The portion of the beam which reflects off the retroreflective surface passes back through the non-uniform convex lens and reflects off of the beamsplitter, and is directed to a photodetector. As an object traverses the beam in the direction of the sensing axis, the leading (or trailing) edge establishes a change in intensity level of the beam portion that reaches the detector. The output of the detector provides a signal representative of the edge position of the object.

Abstract: An automatic blister system includes an inspection station into which blisters are delivered in seriatim. After inspection the blisters are removed from the inspection station. A transport assembly conveys the blister through the inspection station. A sensor or detector is mounted in the inspection station directed at the path of travel of the blisters. In addition, a high speed camera is in the inspection station which is actuated by the sensor for capturing a picture of the blister. The characteristics of the blister in the picture are then monitored.

Abstract: A package inspection apparatus comprising a tray having a peg inclined for mounting a package thereon, a conveyor having a pair of chains for carrying the tray, an inspection box mounted on the conveyor, a light source and a camera mounted in the inspection box for inspecting for bunch winding and bulge winding of the package, and a package weight measuring instrument vertically movably mounted between the chains.

Abstract: A device for detecting a semiconductor wafer in a non-contact manner irrespective of transparency or opacity thereof. At positions corresponding to a plurality of wafers loaded on a carrier, a plurality of light emitting/receiving sensors and a plurality of light receiving sensors are correspondingly provided in pairs in such a manner that their respective light emitting/receiving surfaces and their respective light receiving surface in pairs confront each other. The light emitting/receiving sensors and light receiving sensors are alternately arranged in two rows lengthwise on a sensor support board. In the case of a transparent wafer, a light sent out from a light emitting section of the light emitting/receiving sensor strikes on and is reflected by the surface of the wafer. The thus reflected light is then detected by a light receiving section of the same light emitting/receiving sensor.

Abstract: Apparatus and method for measuring the reflectivity of a product for use in optical sorting machines that is insensitive to product size and orientation. The percentage reflectivity of a product passing a background is corrected by a frame fill factor, which is representative of the percentage of the viewing frame occupied by the product being sorted.

Abstract: A method and apparatus for detecting the presence of an impurity within a substantially spherical object, such as a pit within a piece of stone fruit as it passes through an inspection zone. An infrared point source light emitting diode positioned on one side of the inspection zone transmits a single light beam across the inspection zone. A linear CCD array for generating a signal that is proportional to the intensity of the light transmitted through the fruit as the fruit passes through the inspection zone is provided and an optical slit for collimating the light beam on the CCD array are provided. An infrared filter is positioned between the lens and the CCD array. Thus, as the fruit passes through the inspection zone and is illuminated by the infrared light source and the intensity of the light transmitted through the fruit is received by the CCD array, a two-dimensional analyzable bit map representative of the cross-section of the object's density is produced.

Abstract: A photosensor is provided with a control circuit that is capable of varying the frequency of light pulses which energize a light source of the sensor. When four consecutive light pulses result in an identical status of a light sensitive component, the frequency of light pulses is slowed to conserve energy. However, when a change in state is recognized by the circuitry of the present invention, the frequency of light pulses is increased in order to more rapidly determine whether or not a change of status has actually occurred. This permits the photoelectric sensor to conserve energy while also being able to rapidly determine whether or not the light path of the photoelectric sensor has changed state from obstructed to unobstructed or, conversely, from unobstructed to obstructed.

Abstract: A parcel detection system works in connection with a stream of parcels, such as might be encountered in connection with bulk mail sorting apparatii. A presence of multiple parcels traveling adjacent one to another is detected with a line scan charge coupled device. A transducer array is disposed perpendicularly to the stream flow. Specular illumination of edges of the parcels is completed to facilitate capturing an image in the CCD array. An analog signal, obtained from the array, includes information representative of a number of adjacent parcels. This information is processed to provide a signal representative of a number of parcels traveling adjacent to one another in the stream.

Abstract: A storage phosphor system includes a storage phosphor cassette autoloader for use with a plurality of cassettes. The autoloader includes first and second endless conveyor belts, which are spaced apart and which have a plurality of outwardly extending shelves in vertical alignment so as to define a cassette read site and a plurality of cassette retaining sites. A drive drives the conveyor belts in unison to transfer cassettes loaded in the retaining sites serially through the read site. A belt position sensor senses the position of at least one of the conveyor belts and produces a signal representative of conveyor belt displacement.

Abstract: A high resolution article handling system serves as an article discriminator or identifier by creating an object silhouette. The objects are singulated on a conveyor and scanned by a linear array of CCD units (2048 pixels per inch) at a scan rate of 10 MHz. Pixel transitions corresponding to object edge points are converted to a single count value from a counter which is synchronized with the scanner. A microprocessor with a first in, first out buffer memory needs only a capacity to handle the count value rather than all data from the pixels. Article orientation is corrected in response to signal generated by determining the count value difference between a reference value and a work article value at only the scan slice windows at equally spaced positions along the article length where differences have been predetermined to be a maximum.

Abstract: A check Sorter-Imager-Processor with two (or more) imaging sites, each lit by a beam through a fibre-optic array, with a lens focusing the beam on each array such that a shift in lens-focus reduces output light from the array--the two sites being thus "matched" in light-intensity by merely focus-adjusting these lenses.

Abstract: To provide a simple way to control full magazine condition in apparatus where films driven to the receiving magazine rest therein one on the other, the method provides for the following steps: sending an IR light signal toward the films in the magazine; letting the signal be reflected by the last arrived film; collecting the reflected signal with a photosensor; having the photosensor emit an alarm signal when the intensity of the light collected thereby is greater than threshold value of the photosensor itself, thereby showing that the last arrived film is too near to the photosensor, because the magazine is full; repeating the above steps every time a film is fed. This method allows also film jammed detection out side the magazine.

Abstract: A sample of powder granules flowing through an online conveyor is removed periodically and fed to a supply hopper where a predetermined amount of granules are stored. A small portion of the granules are removed from the supply hopper and continuously fed to the upper surface of a rotary table to form a single layer thereon. The sample on the table is optically sensed to detect foreign particles. The foreign particles are removed and subsequently the good particles are removed and passed to a weighing hopper. The ratio of good product after sensing and the sample in the hopper is calculated to determine the relative amount of foreign particles flowing in the system.

Abstract: A wafer cassette mapper detects the presence or absence of a wafer in a particular corresponding pair of slots in a wafer cassette, as well as a cross slotted condition in which a wafer is not aligned in a corresponding pair of slots. The wafer cassette mapper includes a base member for receiving a standard slotted wafer cassette, the base member supporting a transmitter/receiver module adjacent the rear of the wafer cassette. The transmitter/receiver module includes two vertical columns of light emitting apertures, coupled to an infrared transmitter array, and a single vertical column, between the two columns of light emitting apertures, of light receiving apertures coupled to an infrared receiver array. Corresponding light emitting apertures in each of the two columns are positioned to illuminate the rear edge of each of the wafers in the wafer cassette at an angle that will cause the diffused reflected light to enter an associated one of the light receiving apertures.

Abstract: The image of a body which is located in a measuring zone is projected by a mirror into a camera having an optoelectric transducer, for instance a row of photodiodes. The stripe pattern is thrown onto the upper side of the body by a light beam which is inclined with respect to the projecting direction, said stripe pattern being imaged together with said body. The shape of the body in the vertical projection is detected by the camera and an associated electronic system, and the elevation of the body is deduced from the position of the stripe pattern thereon. Three dimensions, i.e. the actual size of the body, are thus determined. A sorting device can be controlled according to the detected size.

Abstract: This invention relates to reading and analyzing the contents of sealed mail. The invention has utility in the sorting of sealed mail and in the matching of mail envelopes and its contents. The contents of sealed mail are read by having a light in the near infrared directed to the sealed envelope and creating an image of the printed matter on the contents by directing the light to an optical detector. The image thus received is analyzed and a determination can be made whether contents are of high value or whether the addresses on the envelope match the addresses of the contents. If the envelopes are not addressed, the address can be printed on the envelope after analysis of the address block of the contents.

Abstract: The present invention is a method and apparatus for selectively altering the sensitivity of an optical sensor. The sensor has both a light source and a detector which are optically aligned with one another. The detector produces a first output signal level in response to light having an illumination intensity greater than or equal to a threshold intensity, and a second output signal level in response to light having an illumination intensity less than a threshold intensity. The sensor further includes the ability to selectively alter the illumination intensity of the light emitted by the light source to a lower level between the threshold intensity and the normal operating intensity. Hence, operating at the lower intensity enables the sensor to detect translucent sheets or facilitates identification of marginally operable sensors.

Abstract: In an edge detector process, a working plane (A) is scanned by a focussed light beam, e.g. a laser beam emitted by a light source (L) projected at an angle of typically 40.degree. to 45.degree. from the working plane. A first and a second detector (D1, D2) receive the scattered light from the working plane. The first detector (D1) is positioned behind a focussing imaging optics (0), such as an off-axis parabolic mirror, which is arranged coaxially, i.e. all round the laser beam, or is positioned below the emitted light beam relative to a main working plane (H). The second detector (D2) is positioned approximately over the light spot produced by the emitted light on the main working surface. The stray light measured by the first detector (D1) is therefore received at an angle to the main working plane, which is equal to or smaller than the angle between the emitted light and said plane.

Abstract: An improved shell egg culling system includes a conveying system having sites for conveying shell eggs, an illuminator together with a video camera in conjunction with a computer having a first algorithm and a second algorithm for determining which of the sites contain shell eggs having broken shells and which contain shell eggs having soiled shells, a plurality of bridges in side-by-side relationship which are controlled by the computer to remove shell eggs having broken shells from the conveying system for discarding, and a platform having a plurality of downwardly directed, suction-activated lifters which are controlled by the computer to remove shell eggs having soiled shells from the conveying system for recycling through a washer.

Abstract: Disclosed are Power Encoder means for imprinting MICR characters on checks, with optical check-sensing means disposed along a check-transport path, including optical skew-sensor means and a transport control arrangement for advancing checks past processing stations according to one or several "velocity-profiles", depending upon the type and/or condition of the check.

Abstract: Document-imager for imaging documents (e.g. checks that are transported past an imaging-site, where the site is illuminated by one (or two) pairs of lamps symmetrically disposed about the site, with image-reflection sent back between lamps to be captured.

Abstract: A reprographic media detector having a source of electromagnetic radiation (12) aimed at a reflector (17) is provided. A first detector (13) is positioned near the paper path for detecting electromagnetic radiation reflected from the reflector and a first portion of the paper path. A second detector (14) is positioned near the paper path for detecting electromagnetic radiation reflected from the reflector and a second portion of the paper path. Outputs of the first detector (13) and the second detector (14) are differentially amplified to produce an output signal indicating when an edge of a media sheet is illuminated by the source of electromagnetic radiation (12).

Abstract: An apparatus for detecting a sheet in a conveying path, comprising a light source and a light receiver on one side of the conveying path and a light-reflecting element in the form of a prism on the other side of the conveying path for reflecting for the light receiver a beam of light emitted by the light source, wherein the prism has a first reflecting surface opposite the light source, a second reflecting surface opposite the light receiver and a third reflecting surface which deflects, in the direction of the second reflecting surface, the beam of light reflected by the first reflecting surface, so that the apparatus is less sensitive to deviations of the position of the prism with respect to the light source and the light receiver.

Abstract: A machine for mounting a ferrule on an optical fiber cable which includes a plurality of function units (11-17) arranged in a line, including a control and display unit (11) and an inserting unit (16) for inserting an optical fiber into a ferrule which has been injected with an adhesive; a plurality of pellets (21-29) for holding a ferrule and an optical fiber cable and traveling along the function units for circulation; a memory divided into a plurality of areas; a presence detector (13) for feeding the memory in a corresponding area with a failure signal if a ferrule or an optical fiber cable is not present on a pellet (23); an adhesive detector (15) for feeding the memory in a corresponding area with a failure signal if a predetermined amount of adhesive has not been injected into a ferrule; a projection detector (17) for feeding the memory in a corresponding area with a failure signal if a predetermined length of optical fiber does not project from a ferrule after the optical fiber has been inserted throu

Abstract: A system for sorting randomly oriented objects of various sizes based upon the size of the object includes a transport for conveying a series of objects from an input location to one of a plurality of output locations. An image system is disposed along the transport for capturing the image of each object to be sorted. An image processor detects the minimum and maximum linear dimension of each object based upon the captured image. The image processor further determines the shape of each object based upon the captured image. The minimum or maximum linear dimension is selected based upon the shape of the object. The object is categorized by size based upon the selected minimum or maximum dimension. Structure is provided for selectively routing the object based upon the categorized object size to one of the plurality of output locations.

Abstract: A system for determining the proper operation of a feeding apparatus includes a detector for detecting the feeding of two or more overlapped documents. The detector is connected to a processor for processing detected information and providing an output signal indicating that the detector has detected the presence of two or more overlapped documents. An adjustment arrangement is connected to the detector for adjusting the detector to detect the presence of overlapped documents for various different types of documents to be utilized with the feeding apparatus. A display is connected to the detector which displays a first condition when no documents are detected by the detector, a second condition when a single document is detected by the detector and a third condition when overlapped documents are detected by the detector. The system may include two or more spaced apart detectors each with their own adjustment arrangement and associated display.

Abstract: A mirror-following imaging method is for reflecting against a rotary mirror lights from an object to be inspected being carried by conveying means to be incident on imaging means so as to make an image of the object in a frame. The mirror-following imaging method comprises the steps of detecting a positional deflection amount of the image of the object in the frame by the imaging means, anticipating a position for the object to be next imaged at, based on the detected positional deflection amount and a conveying speed of the conveying means, and rotating the mirror corresponding to the anticipated position. The mirror-following imaging method enables the object to be inspected to be correctly followed by the mirror.

Abstract: A support member for supporting objects undergoing inspection, the support member having an uppermost layer whose color is highly reflective in predetermined wavelengths in the range 580 to 1000 nm, the uppermost layer being in direct contact with a further layer which further layer is disposed below the uppermost layer and which reflects at least 70% of any light falling on it having predetermined wavelengths in the range 360 nm to 870 nm.

Abstract: The cylindrical container's inner surface tester extracts image information about the opening portion and the deformation of the inner surface of a test cylindrical container through an image recognizing technique, and checks the circularity of the opening portion of the container. According to the image information, it specifies the position of a test cylindrical container as a predetermined position. Since it sequentially checks a series of cylindrical containers, the adjacent point between the containers must be identified. Then, the cylindrical container's inner surface tester identifies the adjacent point of cylindrical containers through calculations and logical operations according to the image information.

Abstract: An apparatus for counting used medical cloths and measuring the quantity of liquid absorbed therein is disclosed. The apparatus comprises a hollow passage way for passing the medical cloths therethrough, an entrance portion for guiding the medical cloths to the passage, a pass detection sensor arranged in the passage for sensing the medical cloths, a weight sensor disposed at the bottom of the passage for sensing weight of dropped medical cloths, and a control unit for operating the output signals of the pass detection sensor and the weight sensor to output the number of dropped medical cloths and the weight of liquid absorbed therein. The control unit comprises a judging element for judging whether counting condition is normal or not according to the TSR of output signals of the sensors. The apparatus further comprises an alarm element for producing alarm signals when the judging element judges the condition abnormal.

Abstract: A semiconductor wafer cassette mapper detects the presence absence of a semiconductor wafer in a particular corresponding pair of slots of the wafer cassette, as well as a cross slotted condition in which a wafer is not aligned in a corresponding pair of slots. The wafer cassette mapper includes a base member for receiving a standard slotted wafer cassette, the base member including transmitter and receiver modules on opposite sides thereof. The transmitter and receiver modules include like pluralities of inwardly facing, aligned light apertures. Each of the light apertures in the transmitter module contains a light emitting infrared transmitter, and each of the light apertures in the receiver module contains an infrared receiver. Control circuitry selectively activates the light emitting transmitters for a predetermined period of time and selectively interrogates the infrared receivers during that period of time to determine if a particular receiver has received light transmitted by a selected transmitter.