Abstract: The invention relates to a method for measuring wear in the lining of a container provided with a pivoted axle and an opening, and a container. Fixing of the coordinate systems (16, 17) of a measuring device (1) and the container (6) is performed by measuring the position of fixing points (P1, P2, P3) in the coordinate system (16) of the measuring device, whereafter the i0 lining (10) on the inner surface of the container (6) is measured. The fixing is performed by measuring the position of the fixing points (P1, P2, P3) mounted in connection with the container in the coordinate system (16) of the measuring device (1) in a situation where the opening of the container faces away from the measuring device while the measuring device is directed towards the container bottom. The container (6) is rotated around its pivoted axle (11) to a position in which the opening (9) of the container (6) faces the measuring device (1). The fixing is performed utilizing the angle difference between angle data (.alpha..sub.

Abstract: A servo controlled laser system is provided which provides a laser output beam having reduced optical noise. The laser system may be any type of laser system and preferably is an ion laser system. The servo controlled laser system includes a laser head providing a laser output beam and a power driver coupled to the laser head which supplies input power to the laser head. The laser system also includes a light detector in the path of the output beam which generates an alternating current signal in response to the amount of optical noise detected in the laser output beam. A signal amplifier is coupled to the light detector for receiving and amplifying the alternating current signal. A wire couples the signal amplifier to power driver compensator circuitry which receives the amplified alternating current signal from the wire and, in response, adjusts the input power to reduce optical noise.

Abstract: A diode pumped laser system includes a laser cavity with an active laser medium. A laser diode, with an emitter region having an output facet that produces light at a frequency .lambda..sub.1, is the pump source for the laser medium. A coupling optics is positioned on an emission path of radiation from the emitter region and is optically coupled and spaced from the diode. The coupling optics produces stray radiation. An optical fiber, with a first end and a second end, is included. The first end of the fiber is oriented with respect to the coupling optics such that radiation from the emitter region is optically coupled into the optical fiber. The second end of the fiber is coupled to the laser cavity. A detector is positioned in a spaced, adjacent relationship to the coupling optics along an emission path of the stray radiation. The detector detects at least a portion of the stray radiation and produces a detected output in response to the stray radiation.

Abstract: A lens configuration integral with the output window of an enclosure at least partly surrounding a source of a beam is provided. In one embodiment, the beam is an anomorphic diverging beam, such as that produced by a diode laser, having differing angles of divergence along parallel and perpendicular axes, and the at least one lens is configured to at least partly equalize the angles of divergence along the perpendicular and parallel axes.

Abstract: In an optical scanning system, a method and apparatus for decoding labels of single or multiple block formats by stitching together partial label segments obtained from multiple optical scans across the label is provided. Partial scans are decoded into strings of character information which are assembled by locating sub-strings of common elements between two strings. Strings in which the common elements occur at the ends are merged by deleting one set of redundant common characters and joining the remaining characters in proper sequence. The method assembles strings in which the common elements occur in the middle of one or both strings by testing for valid string combinations made by deleting characters adjacent to the common sub-string, on opposing ends of each string, and merging the resulting strings. Feature characters, parity information, checksum digits, and other label structural characteristics are used to verify resulting strings and completed blocks and labels.

Abstract: A bar code scanning system such as for use in retail checkout in which the scanning system has a conveyor defining a first surface and a second surface disposed adjacent the first surface and arranged generally orthogonally thereto forming a scan volume therebetween; sets of pattern mirrors positioned adjacent the respective surfaces; and one or more laser beam sources associated with a rotating mirror polygon for producing scan patterns which are routed to the pattern mirrors and out through the respective surfaces into the scan volume.

Abstract: A method and apparatus for increasing the speed of scanners reading multiple bar code symbologies by changing the order of priority in which the various symbologies are tested by the decoder. After a particular symbology has been read a given number of times in a row, its priority is increased. A particular symbology will continue to advance in priority the more often it is read until it becomes the highest priority symbology.

Abstract: An optical system and method for data reading in which a light source generates an optical beam directed toward an object to be read and a variable aperture mechanism positioned in the outgoing light path establishes at least two separate focal planes. The variable aperture device may comprise a variable aperture system in which the size of the aperture is selectively varied about a range within the diffractive limit of the light beam. A preferred aperture mechanism is a liquid crystal aperture with one or more aperture regions which are selectively or consecutively activated. The optical system therefore establishes two or more separate waist locations from a single light source resulting in greater depth of field or multiple depths of field.

Abstract: An active etalon comprising a laser gain chip interposed between an input mirror and an etalon end mirror is provided. In an intracavity frequency-doubled solid-state laser, a pump source emits pump radiation which passes through the input mirror and into the laser gain chip. The laser gain chip lases in response to the pump radiation to produce fundamental laser light. The etalon end mirror reflects a portion of the fundamental laser light back into the laser gain chip and transmits the remaining portion of the fundamental laser light into the laser cavity. The input mirror reflects substantially all of the fundamental laser light into the laser gain chip. The portion of the fundamental laser light which passes through the etalon end mirror may be frequency doubled by a frequency doubler chip and a portion thereof transmitted through the front end of the laser cavity to form the output laser beam.

Abstract: A non-linear frequency conversion device is tunable over a wide tuning range. An input source provides a first input beam with a frequency .lambda.1. A first frequency conversion crystal has an input beam face that is cut at a phase matching angle .theta.1 and is positioned on a first stage at a stage angle .alpha.1. The first frequency conversion crystal provides frequency conversion of the input beam of frequency .lambda.1 to a selected frequency .lambda.2 of a first portion of the selected tuning range. A second frequency conversion crystal has an input beam face that is cut at a phase matching angle .theta.2 and is positioned on a second stage at a stage angle .alpha.2. The second frequency conversion crystal provides frequency conversion of the input beam from a frequency .lambda.1 to a selected frequency .lambda.3 of a second portion of the selected tuning range.

Abstract: A laser bar code system is described which includes a first scan module releasably affixed to a housing, which scan module is readily interchangeable with and plug compatible with a second scan module which is configured at least partly differently from the first scan module. In addition, a partitioned scan module is described which comprises a first laser diode subsystem, a first scanning subsystem, a first collection subsystem, and a first signal processing subsystem, a selected one of which is releasably affixed to a chassis, and readily interchangeable and plug compatible with a second laser diode subsystem, a second scanning subsystem, a first collection subsystem, and a second signal processing subsystem, respectively, which is configured at least partly differently from the first.

Abstract: An optical system and method for data reading. The preferred system is directed to a scanner which includes a multiple beam service, such as a laser diode and a beam splitter which generates first optical beam and a second optical beam, the first optical beam being directed toward one side of a scanning optical element such as a rotating polygon mirror and to a first mirror array, the second optical beam is being simultaneously directed toward a second optical element such as another side of the rotating polygon mirror and then to a second and a third mirror array. The first mirror array is configured to generate a scan pattern through a vertical window and the second and third mirror arrays are configured to generate scan patterns passing through a horizontal window. In combination, the three mirror arrays generate three sets of scan lines so as to scan the bottom and all lateral sides of an object being passed through the scan volume.

Abstract: A pipe alignment system and method is provided for positioning a pipe line along a predetermined path. A light transmitter generates a reference light beam along which the pipe line is to be positioned. The light beam has wavelengths substantially in the green portion of the optical spectrum. An optical target is positioned at one end of each pipe section to assist in alignment thereof. Preferably, the optical target has a green tint which filters the green light from ambient light. The optical target may also have reference indicia thereon to assist in aligning the target with the reference beam of light.

Abstract: A method and apparatus for determining the transitions between binary levels of an input signal such as a scanned bar code label by detecting zero crossings of an approximated second derivative of the input signal. Samples of the input signal are obtained by using delay lines, sample-and-hold circuits, an analog shift register or similar device. The first derivative of the signal is approximated by the slope of a straight line between two sampled points on the waveform. The second derivative is approximated by the difference between two first derivatives. Zero crossings of the second derivative indicating transitions of the input signal may be determined either by detecting a signal peak on both sides of the zero crossing, or by comparing the second derivative signal to zero when the first derivative exceeds a positive or negative threshold. The time between sample points may be adjusted to match a particular range setting of a scanner having a plurality of range settings.

Abstract: A tunable laser system having a wide tunable range, and narrow line widths, achieves relatively high output powers. The tunable laser system includes a master optical parametric oscillator which generates a seed beam, and a power optical parametric oscillator which is responsive to the seed beam to generate a narrow line width, high power output beam. The master OPO and power OPO comprise gain media consisting of BBO, tunable over a range from about 400 nanometers to more than 2000 nanometers. The master OPO includes line narrowing elements, such as a tunable grating, which limits the line width of the output beam to less than one wave number (centimeter.sup.-1). Pump energy is supplied to the master OPO and power OPO using a Nd:YAG laser with a harmonic generator, so that the second, third, or fourth harmonics of the primary 1064 nanometer line of YAG can be used to pump the BBO crystals. The power OPO may be an unstable resonator.

Abstract: A solid-state laser comprises a pump diode for generating pump radiation and transmitting the pump radiation into a laser cavity. The pump radiation passes through an entrance mirror and enters a laser gain chip which lases to produce fundamental laser light. The fundamental laser light passes through a harmonic reflector and a first dispersive element and is frequency doubled by a frequency doubler chip to produce harmonic laser light. The harmonic laser light passes through a second dispersive element and impinges on a mirrored surface. A portion of the harmonic laser light passes through the mirrored surface to form the output beam of the laser. The remaining portion of the harmonic laser light is reflected back into the laser cavity. First and second dispersive elements control the phase of the harmonic laser light in the laser cavity such that substantially all of the harmonic laser light is in-phase when the harmonic laser light impinges upon the mirrored surface.

Abstract: A method and apparatus for reading encoded symbols such as bar code labels at any orientation to a raster scanning device. A pattern of virtual scan lines is selected over the two-dimensional imaging region according to the specifications of the images to be read. The pattern is generated by defining a family of parallel lines of a certain spacing and rotating the family by a specified angle until the two-dimensional imaging region is covered. Only the data at selected raster locations on the virtual scan lines is stored and processed. One-dimensional signal processing methods are used to detect edges and decode the encoded symbols.

Abstract: A diode pumped, multiaxial mode, intracavity frequency doubled laser resonator has high amplitude stability, meaning that the percent root mean square noise (% RMS) of the doubled output beam power is low. A diode pump source supplies a pump beam to a laser crystal positioned in a resonator cavity and produces a multiaxial mode infrared beam that is incident on a doubling crystal, also positioned in the resonator. A frequency doubled output beam is produced that has an RMS of less than 3%. The laser is highly efficient, provides high output power and its output beam is of high spatial quality.

Abstract: A controller including a closed loop servo system for a laser, or other entity is capable of substantial reductions in predictable, periodic noise such as the line noise induced by the source of alternating current electrical power, and in random noise as well. The servo circuit includes resources which develop a stored version of the predictable noise and uses the stored version of the predictable noise to compensate for the predictable noise. According to another aspect, the servo circuit includes resources which automatically adjust loop gain as gain in the entity being controlled and the loop as a whole system varies. The resources which generate the stored version of the predictable noise may be operated in either analog or digital formats. The sampling resources include, in an analog/digital embodiment, a plurality of charge holding devices, Multiplexing circuitry is coupled to the charge holding devices, and connects a selected charge holding device to a sample node which receives the feedback signal.

Abstract: A point of sale (POS) bar code scanner such as in common use in retail stores includes provision for reading bar coded redemption coupons (or other bar coded documents redeemable for value) in a manner secure from a human operator. Integration of functions between the POS scanner and the coupon reader varies with different embodiments described. Through software associated with bar code decoding logic, a comparison is made between information on a validation coupon and information on items presented for purchase, and a decision is made as to whether the redemption coupon is valid and redeemable in this transaction. In one embodiment, the bar code scanner simply receives the redemption coupon face down on the product scanner window, and integrated decode logic of the scanner identifies the bar code as belonging to a redemption coupon, then makes the comparison and validation of the coupon for the particular transaction.