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WO1995016973A1 - Lecteurs portables de fichiers de donnees - Google Patents

Lecteurs portables de fichiers de donnees Download PDF

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Publication number
WO1995016973A1
WO1995016973A1 PCT/US1994/013323 US9413323W WO9516973A1 WO 1995016973 A1 WO1995016973 A1 WO 1995016973A1 US 9413323 W US9413323 W US 9413323W WO 9516973 A1 WO9516973 A1 WO 9516973A1
Authority
WO
WIPO (PCT)
Prior art keywords
data file
image
reader
focal range
process according
Prior art date
Application number
PCT/US1994/013323
Other languages
English (en)
Inventor
Laser Vadim
Original Assignee
Norand Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from PCT/US1994/005380 external-priority patent/WO1994027250A1/fr
Application filed by Norand Corporation filed Critical Norand Corporation
Publication of WO1995016973A1 publication Critical patent/WO1995016973A1/fr

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Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/14—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation using light without selection of wavelength, e.g. sensing reflected white light
    • G06K7/1404—Methods for optical code recognition
    • G06K7/1408—Methods for optical code recognition the method being specifically adapted for the type of code
    • G06K7/1417—2D bar codes
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K17/00—Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
    • G06K17/0022—Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations arrangements or provisions for transferring data to distant stations, e.g. from a sensing device
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/10544—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation by scanning of the records by radiation in the optical part of the electromagnetic spectrum
    • G06K7/10554—Moving beam scanning
    • G06K7/10564—Light sources
    • G06K7/10574—Multiple sources
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/10544—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation by scanning of the records by radiation in the optical part of the electromagnetic spectrum
    • G06K7/10712—Fixed beam scanning
    • G06K7/10722—Photodetector array or CCD scanning
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/10544—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation by scanning of the records by radiation in the optical part of the electromagnetic spectrum
    • G06K7/10712—Fixed beam scanning
    • G06K7/10722—Photodetector array or CCD scanning
    • G06K7/10752—Exposure time control
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/10544—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation by scanning of the records by radiation in the optical part of the electromagnetic spectrum
    • G06K7/10792—Special measures in relation to the object to be scanned
    • G06K7/10801—Multidistance reading
    • G06K7/10811—Focalisation
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K2007/10524—Hand-held scanners
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K2207/00—Other aspects
    • G06K2207/1011—Aiming
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K2207/00—Other aspects
    • G06K2207/1013—Multi-focal

Definitions

  • TECHNICAL FIELD This invention relates generally to bar code readers, and more particularly to an improved portable device for reading portable data files and the like.
  • BACKGROUND ART Existing two-dimensional portable bar code readers employ a mechanically scanned laser beam.
  • the beam is mechanically scanned horizontally as in conventional, one dimensional bar code scanners, while it is also manually scanned vertically with a downward motion of the hand or wrist.
  • the laser beam is mechanically scanned in both the horizontal and vertical directions utilizing a raster.
  • laser readers require that the scanning beam pattern be accurately aligned with the label symbology, with the degree of accuracy being a function of the vertical height of the coding elements versus the horizontal width. Further, reading the two dimensional codes line by line requires stitching separately read lines or words after they are read. Some two dimensional codes (portable data files and the like) do not provide for stitching. A further limitation of laser scanners for two-dimensional reading is that they require a significant amount of time for the label to be read, which df course requires that the scanner remain accurately aligned with the label throughout the reading process.
  • the present invention utilizes either: (1 ) a pair of two-dimensional photosensitive arrays (such as charge coupled device arrays), a pair of pointing beams for producing a pair of elongated bright spots on a target, an optical string, control electronics, and a power supply; or (2) a single two-dimensional photosensitive array (such as a charge coupled device array), a pair of pointing beams for producing a pair of elongated bright spots on a target, an optical string, control electronics, and a power supply. Both disclosed embodiments utilize the arrays to pick up label images, convert the image to electrical signals, and process the signals with a microprocessor.
  • each sensor has its own lens system, which provides the proper amount of overlap between the two images produced by the separate optical strings.
  • a focus indicator may be provided to facilitate a user in placing labels to be read at the correct distance from the reader.
  • FIG. 1 depicts a conventional pair of sensors, each with its own lens, and shows the image overlap provided with the lenses at various positions;
  • FIG. 2 depicts the sensor and lens system of the invention and its corresponding image overlaps;
  • FIG. 3 is an enlarged view of the positioning of the left lens of FIG. 2;
  • FIG. 4 is a block diagram of the present invention
  • FIG. 5 is a positioning device of the present invention
  • FIG. 6 is an alternative first embodiment of an aiming device
  • FIG. 7 is a diagrammatic illustration of the components of a second embodiment wherein a single two-dimensional photosensitive array is utilized;
  • FIG. 8 is a graphical representation of beam signal outputs from a reader according to the second embodiment described herein;
  • FIGS. 9A through 9H together comprise an electronic schematic of an exemplary single sensor embodiment of the present invention
  • FIG. 10 is a flow diagram illustrating an exemplary program structure for operating the embodiment of FIG. 9A through 9H;
  • FIG: 11 is a side elevational view of an exemplary embodiment of a single sensor portable data file reader module adapted for use with a hand-held data terminal such as illustrated in FIGS. 13 and 14;
  • FIG. 12 is an elevation view of a second exemplary embodiment of a single sensor portable data file reader module adapted for use with a hand-held data terminal such as illustrated in FIGS. 13 and 14A-14B;
  • FIG. 13 is a perspective view of a hand-held data terminal illustrating an exemplary module embodiment of the present invention residing in a pod for attachment to a hand-held data terminal;
  • FIG. 14A is a top perspective view of a second hand-held data terminal containing an exemplary module embodiment of the present invention
  • FIG. 14B is a bottom perspective view of the terminal of FIG. 14A.
  • BEST MODE FOR CARRYING OUT THE INVENTION The following United States Patent Applications are incorporated herein in their entirety by reference: (1 ) USSN 08/298,345 filed on 29 August 1994; (2) USSN 08/170,120 filed on 17 December 1993; (3) USSN 08/067,384 filed on 25 May 1993; (4) USSN 08/060,404 filed on 11 May 1993; and (5) USSN 07/947,673 filed 21 September 1992.
  • FIG. 1 depicts such a system based on two lenses, one for each sensor.
  • This system produces the desirable amount of overlap between the left and right images only when the target label is positioned at a fixed distance from the sensors.
  • a label positioned in the vicinity designated by b would be in the correct position so that the half images would overlap properly, but the position a would produce a missing central area, while the position c provides too great an area of overlapping, thereby defeating the purpose of using two sensors.
  • FIG. 2 also depicts the configuration of an exemplary first embodiment of the present invention.
  • two sensors are used, each with its own lens. These sensors are fixed in a common plane.
  • Automatic focusing is provided by placing the lenses on a carriage that moves toward and away from the sensors. These lenses are mounted on the carriage in such a way that, as the carriage moves away from the sensors, the distance between lenses decreases. As the carriage moves toward the sensors, the distance between the lenses increases.
  • the lines k-k' and m-m' represent the trajectories of the left and right lenses corresponding to the carriage position moving from c to a.
  • the zones A, B, and C correspondingly show the amount of image overlap between the left and right halves of the total field of view of the system.
  • FIG. 3 illustrates, in greater detail, the position of the left lens during focusing.
  • the individual lens viewing angle must be larger than would be required for ordinary imaging of the same field since the axis of the sensor's sight (originating in the center of the sensor) skews away from the optical axis of the lens when the carriage is in other than the midpoint position.
  • the block diagram of FIG. 4 depicts the major components of a portable data file reader.
  • a two-dimensional CCD device or the like may be utilized as an image sensor for reading two-dimensional optical information sets
  • two problems must be overcome: first, the difficulty inherent in processing the data produced by a two-dimensional array, and second, the difficulty inherent in minimizing memory space requirements when working with the array's data output.
  • the present invention solves these problems in part via utilization of the
  • ROM Read Memory
  • HVC pulse control circuit 7 allows the microcontroller 8 (referred to as a DSP) to have direct control over the sensor 1 scanning processes via HVC pulse control circuit 7.
  • This HVC circuit generates the clock pulses necessary for moving electrical charges from the photodiodes to the vertical shift registers, for moving charges in the vertical registers, for shifting them inside the horizontal shift register and for controlling the correlated double sampling device (CDS) 2.
  • CDS correlated double sampling device
  • the vertical driver 4 serves as a power stage for the vertical clock pulses.
  • the microprocessor 8 originates the control signals to the HVC chip 7. These signals, where a CCD type device is utilized, cause the CCD to perform an image charge transfer, a line by line vertical shift and a pixel by pixel horizontal shift.
  • the analog signal appearing on the output of the CDS chip 2 is available to the inputs of the A/D converter 3 and the comparator 5.
  • the other input of the comparator is connected with the output of the D/A device 6.
  • the D/A is equipped with an internal input latch. This architecture provides: (1 ) line shifting separately from pixel scanning;
  • An exemplary solution is to take a service image or service frame, measure • certain parameters of the image such as image quality (contrast, brightness, sharpness, and the like) adjust the sensor control parameters and take a second improved image frame.
  • image quality contrast, brightness, sharpness, and the like
  • the threshold function is a 3-D surface that is stretched in the coordinate of x and y sensor pixels and having vertical coordinate as the image brightness or illuminance. If properly calculated, this surface must intersect the image 3-D function on the middle level between the dark and bright levels of a portable data file image. Having only about 100 points, representing the threshold surface, small memory storage is required.
  • the DSP outputs the threshold points to the D/A converter at the appropriate moments during the frame scanning. These points are locked in the D/A's latch until they are updated with the following values by the DSP.
  • the comparator 5 compares each pixel value with the threshold surface and produces a high contrast black white image. This compressed image data is read by the DSP either through polling or the interrupt, which occurs at each transition from black to white and from white to black.
  • FIG. 5 depicts a reader positioning apparatus.
  • S1 and S2 each produce illuminating beams, which converge at a position from the reader where a two- dimensional bar code is focused.
  • the illuminating spot is rectangular, and outlines the viewing area.
  • An alternative first embodiment of a reader aiming device is depicted in FIG. 6.
  • S1 and S2 produce narrow beams of light which converge to indicate the center of the viewing area and the optimum focus distance.
  • FIGS. 7 and 8 depict a second exemplary embodiment for a two- dimensional portable optically readable information reader.
  • two pointing beams are provided ⁇ S1 and S2) for producing elongated bright spots (a and b) on a target surface Q.
  • ⁇ S1 and S2 two pointing beams
  • a and b elongated bright spots
  • both spots (a and b) merge.
  • the spots (a and b) are separated by a distance m, which is a function of the displacement of the target surface from the best focus position.
  • the beams may have a wavelength selected from the visible portion of the electromagnetic spectrum (such as those produce from red or green LED's), or infrared sources may be utilized.
  • the elongated profile of the beams facilitates capturing of the spots by the array during the taking of a service frame (FIG. 8), which is processed much faster than an ordinary data frame. This reduction in processing time is accomplished by simply skipping most of the horizontal lines in the frame and studying only about three percent (3%) of the regularly spaced lines.
  • Elongated or fan shaped spots (a and b) are preferred since round or narrow spots may be missed if the spot's image fell between the active horizontal lines of a service frame.
  • the distance m is then measured by the reader's computer and is displayed on the indicator (e.g., as a line of variable length, or as a sound of variable pitch) such that an operator may quickly adjust the distance between the reader and the target even where the label to be read and the spots (S1 and S2) are not visible.
  • the indicator e.g., as a line of variable length, or as a sound of variable pitch
  • the distance m between the spot images is defined as: m - b - a and a and b are horizontal coordinates of the spots in the service frame, it becomes negative when a > b, this is true when the target surface Q is out of range. So the sign of the m distance is an indicator of whether the surface Q is too close or too far from the best focus distance.
  • the computer may turn the beams (S1 and S2) on and off or otherwise control the amount of energy in each separately in sequential service frames.
  • the "service frame” provides all necessary information for adjustments, so an image of acceptable quality can be made, such that the "info frame” may be processed successfully and quickly.
  • the selected sensor for this application has a matrix of 752 x 582 useful pixels; (2) there are two fields: odd and even; (3) each field consists of 291 interlaced horizontal lines; (4) each line has 752 pixels; (5) any one field contains sufficient data for a "service frame", therefore after processing one "service field” a decision may be made regarding adjustments before another "service field” or an "info frame” is taken.
  • each line is divided in 16 sections of 47 pixels each; (2) one half of each section (24 pixels) is taken for processing, while another half (23 pixels) is skipped; (3) out of the 24 pixel values two extreme values, brightest and darkest, are found and their differences are stored in a "modulation array".
  • the modulation array is organized as a OfH x ObH (16 x 12 decimal) matrix.
  • a mean value for each of the 24 pixel strips is also calculated and stored in the "threshold array", organized similarly to a "modulation array”. The examples of both arrays are shown in the following tables:
  • the modulation array reflects areas of data activity in the image frame.
  • the rectangular area with the xy coordinates (column * row) of: 62, 65, a2, a5 has elevated modulation values and indicates the image of the label (in this particular example a UPS-code label was used.).
  • the next procedure pinpoints the middle of the area of interest.
  • a low pass spatial filter is applied to the array of modulations as a running window of 3 units wide, independently of horizontal and vertical coordinates.
  • the result of this processing is the two linear arrays (14 and 10 values long correspondingly). Maximum values (and the label middle) is indicated in bold typeface.
  • the next object is to identify the boundaries of the label area.
  • a tolerance value is calculated as a function of an average modulation in the middle of the label (Mm) and average modulation for a large vicinity, surrounding the label (Mv).
  • the modulation values are being compared with the tolerance value, starting from the determined label center, and moving outward until lesser than Tm values are found.
  • One more row or column is then added to this area for safety.
  • the x and y coordinates, outlining the zone of the label are stored. These coordinates are used for optimum processing of the info-frame. All lines preceding (and following) the outlined zone in the frame may be disregarded. The information positioned to the left and to the right of the outlined zone may also be disregarded and need not be acquired. This process of line skipping and pixel skipping substantially reduces the image processing time. Threshold surface values may be found by simply averaging 9 threshold values for a 3 x 3 matrix surrounding the determined label center and applying this averaged threshold for the whole zone.
  • Ambient light conditions may commonly range from 3 to 100,000 lux.
  • An office illuminated by fluorescent lamps typically ranges from 300 to 500 lux. Fluorescent lights normally flicker at a frequency of twice the alternating power source frequency.
  • a preferred embodiment of the present invention should work in flickering lighting conditions and be adjustable from 30,000 to 1.
  • the ratio between the maximum and minimum instant values of illumination intensities are normally on the order of 3 to 1 (where 90° phase shift lighting is not utilized). It is also necessary, in a preferred exemplary embodiment that sensor sensitivity adjustments take place in an order of milliseconds such that the amount of time remaining for image acquisition and decoding is optimized.
  • the present invention describes a method and apparatus for reading two-dimensional optical information sets, which delivers image information sequentially in "frames" which are divided in two fields where a interlaced type television sensor is utilized. Where a non-interlaced sensor is utilized each "frame” constitutes a single field. According to the present invention these fields may be classified into two groups, i.e., "service-field” and "information field.” Service fields are processed much more rapidly than are information fields.
  • sensitivity adjustments may be made according to the following method:
  • a first field is taken with a default exposure of 417 ⁇ s where a non- interlaced sensor is utilized. Where an interlaced sensor is utilized the first field is exposed for 417 ⁇ s and the second field is exposed for 50 ⁇ s.
  • the first field is analyzed to determine the ambient light level (illumination level). Where the level of illumination of the first field is insufficient the exposure time is increased, in such a case two conditions are possible:
  • the signal level is determined to be reliable for calculating an optimal exposure time (in such a case the exposure time is modified accordingly and an information- field is acquired).
  • the maximum exposure time is 4.17 ms (based upon empirical studies of image smear caused by hand motion and the like), and the tolerable exposure time is between 4 to 5 ms (by selecting 4.17 ms certain advantages are obtained). If the required optimum exposure is between 4.17 ms and 12 ms (dim level), the information-field is taken with 4.17 ms exposure and the ADC reference levels are adjusted to preserve contrast ("image normalization"). If exposure time is calculated to be more than 12 ms (dim level), then auxiliary lighting is utilized (xenon strobe light or the like) during acquisition of the information-field.
  • the signal level is found to be too small to calculate optimum exposure.
  • the auxiliary light source is also used (assuming very dark ambient lighting conditions).
  • the . apparatus begins to obtain "service fields.”
  • the DSP processes these "service fields” rapidly since only a few lines distributed throughout the field are processed.
  • the DSP measures the signal level and adjusts exposure to within optimum limits.
  • an apparatus may then produce two beams of visible light (with the imaging lens, for example, situated between them). The beams converge in one spot at the targeted distance.
  • the DSP may activate the beams whenever it is desirable to obtain a field with the beam spots present.
  • the apparatus of the present invention may obtain range and focusing information by analyzing the shape of the fiducial marks produced by the beams. Likewise, the apparatus may simply obtain an image when beam convergence is obtained.
  • embodiments may utilize only three horizontal lines in the center of the field (fiducial spot carrying area). Since only a limited accuracy of range to the target is required (as determined by the optical string depth of field) it is only necessary to measure the width of the area covered with the spots. In order to increase sensitivity it is possible to subtract the field taken with the beams off from the field with the beams on. The result may be integrated so as to distinguish weak contrast beam spots (this condition occurs whenever ambient lighting is bright [the use of high intensity orange LED's in a pulse mode is desired so as to maximize instantaneous contrast]). In order to facilitate operator visibility a long current pulse to the LED's may be employed whenever the DSP is not obtaining an image.
  • a pair of LEDs may serve two purposes, namely operator aiming and focusing.
  • the apparatus simply takes an image when the array is at the correct distance from the optically readable information.
  • an operator may simply aim the apparatus at the information to be read at the approximate in focus distance from the information.
  • the operator simply points the LED spots at the information to be read and moves the apparatus away from or closer to the information and the apparatus obtains an image as soon as the two LED spots converge.
  • FIGS. 9A through 9G comprise an electrical schematic which collectively illustrate an exemplary single array embodiment of the electrical components of a present invention.
  • FIG. 9A illustrates the timing generator (U3) provides timing and control signals to the driver (U1 ) which in turn controls a two-dimensional array via U2. External shutter control and operation is facilitated via U4A and U4B and supporting circuitry.
  • the timing generator (U3) is also capable of independently providing shutter timing signals to the array (20 ms to 0.1 ms). However, the external shutter in an exemplary embodiment is capable of shutter speeds down to 2.0 ⁇ s. This configuration allows continuous selection of an exact exposure setting rather than a forced closest setting.
  • FIG. 9B is a continuation of the electrical schematic partially illustrated by FIG.
  • U8 is operates a 32 MHZ device operating at the array frequency of 28.3 MHZ.
  • the core logic (U10) for the CPU is an address decoder coupled with a latch (U9) and the address bus driver (U12 and U13).
  • the reset circuit, memory logic, and buffers are also illustrated.
  • An exemplary driver circuit for a display is also shown.
  • FIG. 9C is a continuation of the electrical schematic partially illustrated by FIGS. 9A and 9B.
  • FIG. 9C illustrates a 32 bit-wide FFT static random access memory (FFT-SRAM; U15-U22).
  • the FFT-SRAM provides a 64 bit by 32 bit memory which acts as a continuous bank transparent random access memory for the CPU (U8).
  • Associated FFT-SRAM logic and buffer components are also illustrated.
  • FIG. 9D is a continuation of the electrical schematic partially illustrated by FIG. 9A-9C.
  • FIG. 9D illustrates an exemplary FLASH EPROM system (U24-U25) providing for software updates while allowing for the access speed of conventional SRAMs. Also illustrated are voltage control for programming the FLASH EPROMs (see also, FIG. 9H).
  • FIG. 9E is a continuation of the electrical schematic partially illustrated by FIGS. 9A-9D.
  • FIG. 9E illustrates the frame SRAM which stores frame images (one of the two array fields). The same field is taken each time rather than a random field.
  • U26-U33 are the memory chips. Since the processor has a 32 bit data bus and the image has an 8 bit resolution the memory is organized as a single 256 kilobyte by 8 bit memory. When the CPU (U8) is reading this memory the memory provides the 8 lower bits and the data bus buffers (U35-U36) provide the upper 24 bits (all 0's). Also illustrated are the associated buffers and logic.
  • the address decoder (U34) allows sequential enablement of each RAM chip (U26-U33) so as to reduce energy consumption.
  • FIG. 9F is a continuation of the electrical schematic partially illustrated by FIGS. 9A-9E.
  • FIG. 9F illustrates the imager having an 8 bit A/D converter (U43).
  • U43 is provided two reference voltages by U40 and U41and their respective latches.
  • U42 is a buffer and amplifier.
  • the array sampler (U44) is also illustrated.
  • FIGS. 9G and 9H generally illustrate the power supplies. G. Description of FIG. 10
  • FIG. 10 is a flow chart illustrating the program logic obtaining an image for a preferred embodiment of the present invention.
  • the array whether a conventional charged coupled array or a CMOS device, first consists of a hardware initialization step wherein the array is purged of any accumulated random charge and variables are set to zero.
  • the Initialization step may begin upon activation of the apparatus through either operator intervention via a keyboard key, voice, or the like, or via code detection means (such as disclosed in USSN 08/277,132), or the like.
  • a sample field (service field) is taken and the quality of the exposure is determined against a set of preset factors.
  • these factors may include a set of predefined conditions which if present are likely to lead to a successful read, i.e., decoding.
  • decoding Where decodability of an image to be taken is not an issue the prospect of successful analysis of a prospective image to be recorded may be determined via a set of other user controllable predefined conditions. For example, it may be seen exposure control is a primary factor, thus, exposure quality may be determined against such a set of standards. If a threshold exposure level is not determined exactly, the apparatus will attempt another field sample at, for example, another exposure setting.
  • Such step may utilize a fuzzy logic or other artificial intelligence means to determine the next most likely setting. If the sample field meets the selected standards then, for example, a set of correction values may be generated for, for example, light non-uniformity, and imaging lens and/or artificial illumination source performance, or the like.
  • the array is then purged and the apparatus is ready to determine whether another selected condition exists. For example, focus quality. In an exemplary embodiment focus is determined via the position of a spot or spots produced by a light emitting diode (LED), or the like, in the field of view of a second field sample.
  • LED light emitting diode
  • Patent Applications (said applications incorporated herein in their entirety by reference): (1) as the reader engine in the "Reader for Decoding Two Dimensional Optical Information" described in USSN 07/919,488 filed on July 27, 1992, USSN 07/889,705 filed on May 26, 1992 (now abandoned), and USSN 07/849,771 filed on March 12, 1992 (issue fee paid September 16, 1993); (2) as a reader engine in
  • FIG. 11 is a side elevational view of an exemplary embodiment of a single sensor portable data file reader module 10 adapted for use with a hand-held data terminal 24 and 28 such as illustrated in FIGS. 13 and 14-14B.
  • a single two- dimensional photosensitive array 18 e.g. a charge coupled device or CMOS array
  • CMOS array charge coupled device
  • the housing 22 extends at its ends perpendicularly to the plane of that portion of the housing 22 to which the photosensitive array 18 is affixed.
  • a left LED 12 is mounted on one such housing 22 extension and a right LED
  • the pair of LEDs 12 and 14 are mounted in such a manner that the center lines of the beams of emitted light converge at the apex of the angle formed by the two said center lines, such apex lying on a line normal to the plane formed by the photosensitive array 18, and such normal line intersecting said plane of the photosensitive array 18, preferably at the center of said array.
  • the distance, d, from the photosensitive array 18 at which the beams of light emitted from the LEDs 12 and 14 converge corresponds to the focal distance of a fixed focus lens 16, said lens 16 mounted on the photosensitive array 18.
  • the fixed focus lens 16 has a focal distance of 8.5 inches and an aperture such that the depth of field of 4.0 inches.
  • the depth of field of the lens 16 allows for images within a range of 8.5 +/- 2.0 inches (6.5 inches to 10.5 inches) to be in focus. This range over which the image focus is maintained aids the human operator who may place the data file reader module 10 at imprecise distances from the data file to be read. So long as the data file reader module 10 is placed within the focus range, the image will be in focus.
  • the lens 18 may have a variable focal length such that long range or short range data file readings may be possible. In an additional further embodiment, the lens 18 may have a variable aperture such that the depth of field and the image brightness may be varied as well. Control of the focal length, depth of field, and image brightness may be processed and controlled by the DSP.
  • a xenon flash tube with back reflector 20 is mounted near the fixed focus lens
  • the xenon flash tube 20 provides supplemental lighting of the data file image to be read when the ambient light conditions are insufficient for proper image exposure.
  • the back reflector of the xenon flash tube 20 provides concentration of the supplemental light on the data file image area and further prevents direct light incident on the photosensitive array 18.
  • the use of the xenon flash tube 20 is controlled by the DSP. I. Description of FIG. 12
  • FIG. 12 depicts a second exemplary embodiment of the data file reader module 10 adapted for use with a hand-held data terminal 24 and 28 such as illustrated in FIGS. 13 and 14A-14B.
  • the photosensitive array 18, lens 16, and LEDs 12 and 14 are mounted to the rectangular or similarly shaped recessed housing 22 at one end of the housing
  • FIG. 13 is perspective view of a hand-held data terminal 28 illustrating an exemplary module embodiment of the present invention residing in an external pod 26 for attachment to a hand-held data terminal 28.
  • the data file reader module 10 is frontally mounted within an external pod 26 such that the opening of the recessed housing 22 faces in a forward direction.
  • the beams from the LEDs 12 and 14 are frontally emitted such that data files to be read are positioned directly in front of said data terminal, lying in a plane parallel to the front edge of said data terminal 28 and parallel to the plane of the photosensitive array 18.
  • FIG. 14A is a top perspective view of a second hand-held data terminal 24 containing an exemplary module embodiment of the present invention.
  • Said data terminal 24 is designed to be used such that it is frequently laid upon a planar surface for input of data by means of a stylus or the like when not used for data file reading. Such conditions of use require said data terminal 24 to remain stable during stylus implemented data input and to remain flush with the surface upon which said data terminal 24 is laid. As required, said data terminal 24 may readily be employed for data file reading purposes.
  • FIG. 14B is a bottom perspective view of the terminal 24 of FIG. 14A.
  • the data file reader module 10 is mounted directly within the hand-held data terminal 24 so that said module 10 is flush or nearly so with the bottom surface of said terminal
  • Said module is mounted such that the beams form the LEDs 12 and 14 are downwardly emitted such that the data files to be read are positioned directly beneath said data terminal 24, lying in a plane essentially parallel with the bottom surface of said data terminal 24 and essentially parallel with the plane of the photosensitive array 18.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
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  • Artificial Intelligence (AREA)
  • Computer Vision & Pattern Recognition (AREA)
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Abstract

Cette invention utilise des réseaux photosensibles à deux dimensions (SR, SL) pour décoder des ensembles d'informations à lecture optique à deux dimensions, qui produisent un meilleur foyer. Une lentille est associée à chacun des réseaux photosensibles qui peuvent se déplacer suivant une trajectoire (K-K', m-m') de sorte que lorsque la lentille s'éloigne du réseau photosensible, la distance entre les lentilles diminue. La distance variable existant entre les lentilles produit des zones d'image (A, B, C) présentant le même chevauchement dans chaque zone.
PCT/US1994/013323 1993-12-17 1994-11-16 Lecteurs portables de fichiers de donnees WO1995016973A1 (fr)

Applications Claiming Priority (9)

Application Number Priority Date Filing Date Title
US17012093A 1993-12-17 1993-12-17
US08/170,120 1993-12-17
US24186694A 1994-05-11 1994-05-11
US08/241,866 1994-05-11
USPCT/US94/05380 1994-05-11
PCT/US1994/005380 WO1994027250A1 (fr) 1993-05-11 1994-05-11 Lecteur portatif bidimensionnel
US29834594A 1994-08-29 1994-08-29
US08/298,345 1994-08-29
US08/332,560 1994-10-31

Publications (1)

Publication Number Publication Date
WO1995016973A1 true WO1995016973A1 (fr) 1995-06-22

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PCT/US1994/013323 WO1995016973A1 (fr) 1993-12-17 1994-11-16 Lecteurs portables de fichiers de donnees

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WO (1) WO1995016973A1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4323925A (en) * 1980-07-07 1982-04-06 Avco Everett Research Laboratory, Inc. Method and apparatus for arraying image sensor modules
US4335302A (en) * 1980-08-20 1982-06-15 R.L.S. Industries, Inc. Bar code scanner using non-coherent light source
US4389103A (en) * 1981-07-24 1983-06-21 Source Technology Corporation Slide projector having two image-projection systems which operate with a single slide tray
US4660096A (en) * 1984-12-11 1987-04-21 Rca Corporation Dividing high-resolution-camera video signal response into sub-image blocks individually raster scanned
JPS6367692A (ja) * 1986-09-09 1988-03-26 Nippon Denso Co Ltd 光学的情報読取装置
US5159455A (en) * 1990-03-05 1992-10-27 General Imaging Corporation Multisensor high-resolution camera

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4323925A (en) * 1980-07-07 1982-04-06 Avco Everett Research Laboratory, Inc. Method and apparatus for arraying image sensor modules
US4335302A (en) * 1980-08-20 1982-06-15 R.L.S. Industries, Inc. Bar code scanner using non-coherent light source
US4389103A (en) * 1981-07-24 1983-06-21 Source Technology Corporation Slide projector having two image-projection systems which operate with a single slide tray
US4660096A (en) * 1984-12-11 1987-04-21 Rca Corporation Dividing high-resolution-camera video signal response into sub-image blocks individually raster scanned
JPS6367692A (ja) * 1986-09-09 1988-03-26 Nippon Denso Co Ltd 光学的情報読取装置
US5159455A (en) * 1990-03-05 1992-10-27 General Imaging Corporation Multisensor high-resolution camera

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