JPS5922269B2 - recognition device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electro-optical reader, in particular to a BarcOde reader in which a code is scanned by an electronic device, first locating this code and then reading and decoding it.

There is an increasing need to quickly and accurately identify items for locating, sorting, and routing purposes.

For example, there is a need for rapid and accurate mechanical identification and sorting to ensure rapid and accurate dispatch of increasingly large volumes of mail. Document identification and classification also
This has become a significant problem in many industries, such as banking and insurance, where significant volumes of documents must be processed reliably on a daily basis. Rapid and accurate interpretation of data displays has also become important in areas that utilize retrievable media, such as railcars. Additionally, warehousing businesses require the ability to quickly and accurately identify the location of stored items for retrieval. Generally, the articles described above are encoded with an optically detectable bar code which requires suitable code recognition equipment for decoding.

Such a recognition device scans across a document of a first size and decodes indicia at a number of vertical (column) positions at each scanning position. Many of the devices previously provided for bar code recognition required critical rigid alignment and matching of documents since irregularities could easily be misinterpreted as encoded data. Conventional code recognition devices have addressed the alignment problem with devices that move the detector or move the document. Both of these operations are tricky and slow. For example, it is generally necessary to detect a reference position along the vertical dimension of the article and move the target to the operating position. Other conventional bar code recognition devices physically position the detector to view the entire encoded data when detecting the reference position. Clearly, both of these devices become limited in terms of cost given the processing time and processing equipment required. Another solution to this problem has been to use multiple sets of detectors to ensure that at least one such detector receives energy from the encoded data. In practice, this requires multiple single units, with the attendant drawbacks of complexity and expense. As noted above, industries that have to handle large volumes of documents are increasingly relying on automatic classification devices that are responsive to encoded data.

The encoded data is printed on the document with ordinary ink, in which case the scanning device must be sensitive to light waves in the visible range. However, the document may also be printed with ink that emits ultraviolet light. In such cases, the scanning device must be sensitive to radiation in the ultraviolet wavelengths. The document is processed with a device that moves the document in a linear motion. However, the document may also be printed mechanically or pneumatically on a cylinder rotating about an axis by means of the transport device. This axis is parallel to the vertical orientation of the data. A variety of devices are available for applying the encoded data to documents, such as standard bar code printers and ink jet printers.

The quality of such prints varies significantly such that in the worst case the encoded data at high magnification appears like a random scattering of ink drops. Accurately and reliably reading and decoding such information requires unconstrained equipment that recognizes common patterns in the encoded data and reveals sharp contours. shall be. In applications where encoded information is used to classify retrievable media, and in the warehousing industry, explicit data is subject to rough handling and some of it is distorted, if not corrupted. However, any data processing device with an identifying part must operate with a much higher degree of reliability than the person chosen to perform the function. In applications where encoded reversible media is in motion, the code identification device must be able to identify articles moving at speeds in the range of 60 miles per hour or more. Code detection devices are also required to operate under extreme environmental conditions, including a wide range of temperatures, and are subject to vibration and shock. The operating tolerances of the bar code recognition device must allow for accurate readings regardless of the normal variations in height, lateral offset, and tilt of the moving object. It is an object of the present invention to provide a plurality of vertically arranged code regions and means for deflecting the energy reflected from the coded data so that the coded data passes through the reading location. The purpose of the present invention is to correct misalignment of encoded data.

In one embodiment of the invention, a recognition device for bar code data of a target is provided with a first device for receiving light waves reflected from the coded data and performing target reproduction of this data. Cooperative with this first device is a second device which biases the light wave energy transmitted from the encoded data and positions the target playback in a previously selected area. An electrical signal is generated by a third device coupled to the first device and responsive to target reproduction of the encoded data.
These electrical signals generate a series of electrical pulses representing an article having bar code data. In accordance with another embodiment of the invention, an apparatus for recognizing bar-encoded data of a target includes a first apparatus for receiving light waves reflected from the encoded data and performing target reproduction thereof. A second device is provided for deflecting the light wave energy transmitted from the encoded data to the first device. A first signal representing an area of encoded data and a second signal representing an area of background are generated by a third device coupled to the first device and responsive to targeted playback of the encoded data. . A summing circuit is connected to receive and combine the first and second signals into a series of voltage pulses representing encoded data. Hereinafter, preferred embodiments of the recognition apparatus of the present invention will be described in detail with reference to the accompanying drawings. As shown in FIG. 1, an electro-optical bar code reading device as an embodiment of the present recognition device uses visible light energy reflected from a target object, near-infrared energy, and a full bar code attached to the object. A first device, an image intensifier tube 10, is utilized as a sensor for detecting a code consisting of a fullbar code 12a, 12b and a halfbar code 12c.

Image intensifier tube 10 is an electronic device that reproduces the image of bar code 12 on a phosphor screen. This image is created by the image intensifier tube 1 at the point of incident light wave energy.
It is the same as the original image of the photocathode positioned within 0 and is often much brighter than this image. All image intensifier tubes are equipped with a photocathode that emits electrons in the same density pattern as the radiation falling on the entrance surface of the tube. These electrons are accelerated and focused onto the phosphor screen by an accelerating voltage. An electromagnetic coil surrounding the image intensifier tube is then energized to deflect the electron beam within the tube, thereby forming a device for accurately positioning the target reproduction on the phosphor screen. The electrons strike the phosphor screen and excite it, emitting a beam of light that reproduces the code that strikes the photocathode. In addition to the image intensifier tube, other light-responsive detectors with scanning capabilities are used to reproduce the bar code data attached to the target.

Such a detector is, for example, a resolution tube with multiple apertures that feed into a photomultiplier tube. The objective lens 14 has the symbol 1
2 and the background area of the target printed with the numeral 12 is collected and the energy is focused onto the photocathode of the image intensifier tube 10.

The image intensifier tube 10 has a coupler 16 coupled at the end of the phosphor screen for the transmitted light rays emerging from the phosphor screen to a series of optical fiber bundles 18 coupled to a matrix of light-responsive sensors 20. It has been done.

A light-responsive sensor is a photomultiplier or photodiode that has the property of producing a signal that varies with the energy of the light waves that impinge on it. That is, the light rays emanating from the target reproduction at 12 of the phosphor screen of the image intensifier tube 10 are directed by an optical fiber bundle 18 to a matrix of light-responsive sensors 20. Each sensor 20 produces a signal that is coupled to a recognition logic circuit 22 that sends a series of recognition pulses to a display 24 and to a lead 26 for coupling to a sorting device or other control device that utilizes the recognition pulses. Depending on the application of the apparatus of Figure 1 and the quality of the bar code to be read, a single optical fiber bundle embedded in epoxy or isolated within a bundle of other optical fiber strands may be used to image the image. From the reinforcement tube 10 to the light response sensor 2
Sends light wave energy to 0.

A minimum of three light-responsive sensors 20 are required to perform barcode reading as illustrated in FIG. 1 by code 12. Multiple optical fiber strands are arranged in a bundle and the light beam is directed to a single light-responsive sensor 20 to read a code that moves at a high rate of velocity past the objective lens 14. Also, some light-responsive sensors 20 vary in the quality of the symbol they attempt to read and the window area that the symbol appears in as it passes through the image intensifier tube 10. In the apparatus described below, fourteen light-responsive setters 20 are arranged in a scanning area covering the viewing window area where the code appears. Each of these sensors 20 includes an optical fiber bundle 18 consisting of multiple strands optically coupled at one end to the image intensifier tube 10 via a coupler 16 and at the other end in contact with the light-responsive surface of the sensor 20. It responds to the light rays that travel through it. The electro-optical bar code reader according to the exploded block diagram shown in FIG.
a power source 2 for energizing an array of lamps 30 to illuminate a window area of the
It has 8.

Transfer device 34 moves article 32 past the irradiation area created by each lamp 30. The light beam reflected from bar 12 is focused by objective lens 14 onto photocathode 36 of image intensifier tube 10.

Electrons emitted from the photocathode 36 are routed through a second device or deflection coil 38 and strike a phosphor screen 40 at the end of the image intensifier tube 10 opposite the photocathode 36. Deflection coil 38 is energized by a deflection voltage from electric wire 42 and deflects the electron beam from photocathode 36 in the X and Y directions. Selective energization of deflection coil 38 causes bar code 12 to appear anywhere within the scan window area and objective lens 14 focuses reflected light wave energy onto photocathode 36 . By varying the deflection voltage to coil 38, the electron beam is positioned at the desired target area of phosphor screen 40. FIG. 3 illustrates an image intensifier tube 10 having an objective lens 14 that directs light energy to a photocathode 36.

Assume that the first binary code in portion 44 appears at the optical axis of objective lens 14 and that the light rays reflecting from lens 14 then impinge on photocathode 36 at the axis of image intensifier tube 10. The electron beam 46 emerging from the photocathode 36 is directed axially through the image intensifier tube 10 and impinges on the center of the phosphor screen 40. In this case, the deflection coil 38 remains deenergized and does not affect the path of the electron beam 46. Now assume that a binary code 48 appears on the opposite side of the vertical optical axis of lens 14. In this case, the light beam reflected from 48 strikes the photocathode 36 at a location 50 offset from the longitudinal axis of the tube 10. Deflection coil 38
Appropriate. - biases the electron beam 52 exiting the photocathode 36 at point 50 to the center of the phosphor screen 40. That is, the deflection coil 38
By properly energizing the offset binary code 48, the binary code 44 seen through the hole in the phosphorescent screen 40 is transferred.
In the same way, it will appear in the target area selected in advance. A phosphorescent screen 40 as shown in FIG.
The light rays emanating from the optical fiber bundle 18 pass through the optical fiber bundle 18 to the signal conditioning circuitry 54 as part of the recognition logic circuit 22.

Signal conditioning circuitry 54 produces column data signals for transmission along communication line 56 to receiving, tracking, and reading logic 58. Data from the preselected scan area is also sent directly from signal conditioning circuitry 54 to display logic 60 which drives display 24. The column data signal input to the logic circuit 58 is sent to the circuit 5.
Conductors 62 directed to each logic element in 8 provide deflection control signals to image deflection circuitry 64 . The signals applied to logic circuit 58 are also utilized to generate recognition pulses by conductor 26 for control purposes or for desired position selection.
The image deflection circuitry utilizes the deflection control signals in conductors 62 to adjust the deflection current in each conductor 42 coupled to the deflection coil 38 to position the target reproduction at 12 on the phosphor screen 40. FIG. 4 shows an expanded configuration diagram of the signal conditioning circuitry 54.

Circuitry 54 couples individual light-responsive sensors 20 to individual amplifiers 66, each operative to add to a comparator circuit 68-75 responsive to the light reflected from each scanned area of the observation area. The sensor output is amplified to the maximum.
FIG. 5 shows a viewing window area 76 consisting of six scan areas spanning the vertical dimension of the viewing window.

Each vertical scanning area is divided into a code image area (hereinafter simply referred to as the code area) B, in each case marked with the letter B, and on each side of this code area is a background image area (hereinafter simply referred to as the background area). ) is located.
These background areas are marked with reference letters Al, A2. Each code area has two rows of optical fiber elements (hereinafter referred to as optical fiber segments), each row consisting of four pieces, for a total of eight pieces for each code area, as shown in area 1B. There is a piece. , each background area consists of a row of four optical fiber sections, for a total of 96 sections within viewing window area 76. each optical fiber section in the scanning area;
That is, a total of eight pieces of the code area, or a total of eight pieces of the background area on each side of a particular code area, are coupled to respective comparator circuits 68-75.

That is, all the optical fiber pieces in zone 1B are
It is coupled to a comparator 68 along with all pieces of A1, 1A2. Each block 68- represents a comparator circuit 68-75.
75 is illustrated with a mathematical formula representing each section of optical fiber segment coupled thereto. FIG. 6 shows a block diagram of each comparator circuit 68-75 showing interconnected scan areas.

Regarding the scanning area 4 of the window area 76, this is the main reading area and is divided into upper sections 4A11, 4B1, 4A21 and lower sections 4A12, 4B2, 4A22. 6th
In the figure, the comparator 71V is in sections 4A11, 4B1, 4A.
The comparator 71L receives light energy from each section 4A12, 4B2', 4A22. Each comparator circuit 68-73 includes an amplifier 80 responsive to one set of eight light-responsive sensors 20 and an amplifier 82 responsive to another set of eight light-responsive sensors.

Each amplifier 80, 82 has an output terminal connected to one input terminal of a differential amplifier 84. Each comparator circuit 68, 69,
At 72 and 73, the output of amplifier 84 is amplified by amplifier 86. In each comparator circuit 70, 71U, 71L, an amplifier 84
The output terminal of is connected to a booster 88. The output of amplifier 88 is further amplified by amplifier 90. comparator circuit 68,
The output of amplifier 86 of 69, 70, 72, 73 comprises a column data signal coupled to logic 58 for receiving, tracking and reading.

In comparator circuit 71L, the output of amplifier 90 comprises the row data signal coupled to logic circuit 58 for area 4. For each comparator circuit 74, 75, this comparator circuit includes a peak detection pulse generation circuit 92 whose output terminal is connected to the input terminal of an amplifier 94. Comparator circuit 7
The output of the amplifier 94 of 4 is FullbarcentrOidhigh (FB
CH) signal and the output of amplifier 94 from comparator circuit 75 is half-centroid high (Halfba Centroid High).
rcentrOidhigh) (HBCH) signal. Both of these signals are coupled to logic circuit 58. 7th
A wiring diagram of comparator circuits 68, 69, 73 including amplifiers 80, 82, 84, 86 is shown in the figure.

Lightwave energy transmitted by the optical fiber section from one of the B sections is directed to a photodiode 96, indicated by wavy line 98. The cathode of diode 96 is connected to the negative input terminal of amplifier 80, whose positive input terminal is grounded. amplifier 8
0.82 is model 509-50 manufactured by Bell Howell. A negative DC voltage is connected to the amplifier 80 and to the anode of the diode 96, both through a resistor 100. The resistor 100 is also connected to ground via a capacitor 102. amplifier 80
The output terminal of is connected to a feedback loop with resistors 104 and 106 connected to the negative input terminal of amplifier 80.
The output signal from amplifier 80 varies according to curve 108 and is connected via capacitor 110 to gain potentiometer 112.

The wiper arm of potentiometer 112 is connected to the positive input terminal of differential amplifier 84 via resistor 114 . amplifier 8
4 can use the LM3l8 type manufactured by National Electronics. The light beam transmitted by the optical fiber section in one of the areas Al, A2 impinges on the photodiode 116 as shown by the wavy line 118.

The cathode of diode 116 is connected to the negative input terminal of amplifier 82, whose positive input terminal is grounded. A negative supply voltage is connected to the amplifier 82 and the anode of the diode 116 together with the resistor 1.
It is connected via 20. Resistor 120 is also connected to ground via capacitor 122. A positive DC energizing voltage is also supplied to amplifier 82 through resistor 124 . Resistor 12
4 is also connected to ground via capacitor 126. The output terminal of amplifier 82 is connected to a feedback loop that includes resistors 128 and 130 connected to the negative input terminal of amplifier 82.

The output voltage from amplifier 82 varies according to curve 132 as shown and is routed through capacitor 134 to gain potentiometer 136. The wiper arm of the gain amplifier 136 is connected to the amplifier 84.
Coupling capacitor 138 and resistor 1 to the negative input terminal of
They are connected through 40. A positive DC voltage is applied to the amplifier 84 via a resistor 142 and a capacitor 144.
and also apply a negative DC voltage to the amplifier 84 through the resistor 14.
6 and via capacitor 148.

The output terminal of amplifier 84 is connected to a feedback loop having a voltage divider network consisting of resistors 150 and 152 in series with capacitor 154. The feedback resistor 156 is connected to each resistor 150,
152 and the negative input terminal of the amplifier. The output from amplifier 84 varies depending on the difference between the outputs of amplifiers 80 and 82 and has a waveform as shown by curve 158.

This output voltage is applied to the negative input terminal of amplifier 86 via resistor 160. A Zener diode 162 coupled to the negative input terminal of amplifier 86 also clamps the input of amplifier 86 to a preselected level. A positive DC voltage is applied to amplifier 86 via resistor 164 . The resistor 164 is also connected in parallel with a capacitor 168 which regulates the voltage across the Zener diode 166 to a preset level. Similarly, a negative DC voltage is applied to amplifier 86 via resistor 170. The resistor 170 is also connected in parallel to the Zener diode 172 and a capacitor 174 which maintains the DC voltage at a preselected level. The output terminal of amplifier 86 is coupled to a hysteresis limit adjustment network.

The network includes a potentiometer 176 and a potentiometer 178 with the wiper arm of potentiometer 176 coupled to the positive input terminal of amplifier 86. A potentiometer 178 is connected to the negative terminal of the DC supply and is grounded to connect the wiper arm to the potentiometer 176. The output voltage of amplifier 86 is a series of pulses, as shown by curve 180, with each pulse representing a full bar in the code sequence. That is, when the bar code enters areas 1B, 2B or 6B, pulse 180 is generated.
will occur. By connecting the background area Al, A2 in the differential geometry to one of the code areas B, the device has improved noise rejection.

The differential geometry of amplifier 84 produces an output that is correlated to the relative difference in the rays striking diode 96 relative to the rays striking diode 116. When diode 116 responds to the background reflecting the beam and diode 96 responds to the bar code reflected beam, the bar code imperfection is blocked by the device. In this way the detection and reading of the code can be improved. FIG. 8 shows an amplifier circuit separate from the circuit of FIG. 7 which, when combined in this way, represents the details of the network 72 for the area 5 of the window area 76. The voltage signal from the comparison circuit 71L is applied to the input resistor 182 connected to the positive input terminal of the amplifier 184, and the voltage signal from the comparison circuit 71V is applied to the amplifier 1 via the resistor 186.
84 to the same input terminal. In this manner, the power from each section 4U, 4L is summed within resistive networks 182, 186 and amplified by amplifier 184. A feedback loop having a resistor 188 is connected to the positive input terminal around the amplifier 184.

A positive DC voltage is applied to amplifier 184 through resistor 190 . Resistor 190 is also connected to ground via capacitor 192. A negative DC voltage is applied to amplifier 184 through capacitor 196 and through resistor 194 to ground. As the amplifier 184, a μA71O type manufactured by Fair-Child Manual Actuating Co., Ltd. can be used. The output from amplifier 184 is sent to circuit 92 of circuit 74 as part of the system which produces a full bar single centroid high signal. FIG. 9 shows the window area 76.
Comparator circuits 70, 71U, 71 scanning areas 3, 4 of
Indicates L.

The input section of the circuit of FIG. 9 is the input section of the circuit of FIG.
This is similar to a circuit that works together. Details of this portion of the circuit of FIG. 9 have been omitted. The light beam transmitted from code area 3B, 4B1 or code area 4B2 strikes photodiode 116, as shown by wavy line 118, and also from background area 3A1, 3A2 and background area 4.
Light rays transmitted by optical fiber section 18 from A1 or background area 4A2 impinge on photocathode 96 as shown by wavy line 98.

The output voltages of amplifiers 80 and 82 are sent to the negative input terminal of amplifier 88 through differentially summed resistor 200 in amplifier 84 which applies the output of terminal 198 to resistor 186 shown in FIG. . The positive input terminal of amplifier 88 is connected to resistor 20
It is grounded through 2. The feedback path of amplifier 88 includes a resistor 204 connected between the output terminal and the negative input terminal of amplifier 88. A positive DC voltage is applied to amplifier 88 via a resistor 206 connected to a capacitor 208 to provide noise filtering. Amplifier 88 also includes a resistor 210 with a capacitor 212 for noise filtering.
It is energized by a negative DC voltage applied through the amplifier 8
The output voltage from 8 appears at terminal 212.

As shown in FIG. 6, this terminal within circuit 71U is connected to comparator circuit 71L. Terminal 21 as shown in FIG.
2 [as part of circuit 71V] is terminal 214 [as part of circuit 7
Amplifier 88 connected to terminal 214] as part of 1L
The output from the circuit 71U is passed through the resistor 216 to the circuit 71L.
is applied to the input terminal of amplifier 90. Further, the output terminal of the amplifier 88 is connected to the input terminal of the amplifier 90 via a resistor 218. The voltage at the input terminals of amplifier 90 is clamped to a preselected highest level by Zener diode 220. The circuit of amplifier 90 is substantially the same as that of amplifier 86 in the circuit of FIG.
It is equipped with 178. The positive DC drive voltage for amplifier 90 is developed through resistor 164 and held at a level formed by Zener diode 166 in parallel with capacitor 168 . The negative DC voltage for amplifier 90 is developed through resistor 170 and held at a preselected level by Zener diode 172 in parallel with capacitor 174. The output waveform of amplifier 90 changes at output terminal 224 as shown by curve 222. The output terminal 224 of the circuit 71L is the logic circuit 5
8 to produce a column data signal. Also shown in FIG. 6, the circuit of FIG.
, 3A2, and code area 3B reflects the light beam to diode 116.

The output voltage of amplifier 84 appearing at terminal 198 is coupled to circuit 92 as an input portion of amplifier 94 to produce a full bar center high signal. Appears at terminal 224. circuit 70
The output of amplifier 90 is a column data signal coupled to logic circuit 58. For circuit 71U, the light beam from background area 4A1 strikes diode 96, and the light beam from code area 4B1 strikes diode 116.
The output of amplifier 84, appearing at terminal 198, is sent to circuit 92 as an input to amplifier 94 to produce a half-balance centroid high signal. This voltage at terminal 198 also passes to resistor 182 of amplifier 184 of comparator circuit 72 of scan area 5. As described above for circuit 71U, the output of amplifier 88 at terminal 212 is routed to terminal 214 of circuit 71L. The output terminal 224 of the circuit 71U is not used. For circuit 71L, background area 4A2
The light beam sent from the optical fiber section 18 to the diode 9
The light rays from the code area 4B2, which are sent to the optical fiber section 6 and sent by the optical fiber section 18, impinge on the photocathode 116. terminal 1
The output of amplifier 84 appearing at 98 is sent to resistor 186 of circuit 72 covering scan area 5. In one embodiment of the present invention, Table 1 shows the numerical values of the components of each circuit of FIGS. 7, 8, and 9.

In particular, the circuit of FIG.
In addition to the circuit shown, and the amplifiers 80, 8 of FIG.
The circuit for 2.84 is the same as the similarly referenced amplifier of FIG. FIGS. 10A and 10B show deflection logic with accept, track, and read logic 58 and six buffered inverting amplifiers 226-231 coupled to signals BZl through BZ6 from each comparator circuit of FIG. circuit 6
4 is shown.

Each inverting amplifier 226-231 couples an output to a flip-flop 232-237, respectively. Considered as a complete code, one or more of flip-flops 232-237 are set as the bar code moves through window region 76 by a change in the state of the BZ signal that cooperates with the code area for this flip-flop.
The logic output of 237 is sent to an input terminal of a priority encoder 238 to produce a digital code on lead 240 to identify the topmost scan area that causes the lowest portion of the barcode to pass through window region 76. This code by conductor 240 is passed to priority encoder 23
The quadrature latch circuit 242, which acts as a memory of the bar code position, is set during the 8 reset. Priority encoder 23
8 returns to the dormant state when resetting each flip-flop 232-237. Quadrature latch circuit 24
The codes stored in 2 are combined via an inverting amplifier 244 to address read-only storage 246. Digital codes coupled to read-only storage 246 address various storage locations and send specific deflection codes from inverting amplifier 248 to shift register 250. Shift register 250 is set and produces an output that sets counter 252 which sends a digital output to converter 254. converter 2
54 sends an analog deflection voltage to the vertical deflection coil 38 of the image intensifier tube 10. The output of counter 252 is also applied to quadrature latch circuit 256 to provide a radix count that initially sets shift register 250. When the bar symbol first enters window region 76, flip-flops 232-237 are set to produce a signal through priority encoder 238 that is related to the location of the bar symbol within the viewing window.

Using this code, send the code to the register 250 and counter 2
52 to read-only storage 246. The value in counter 252 is combined via transducer 254 to reposition window region 76 of image intensifier tube 10 by energizing deflection coil 38 so that the bar sign appears closer to the center of the window. do. Depending on the initial location of the first bar, the first correction is insufficient to center the code on the viewing window.

The image intensifier tube 10 is configured to provide additional vertical correction.
energizes the horizontal deflection coil to cause the first deflection to pass through the viewing window again. The output terminal of each buffer amplifier 226-231 is connected to one input terminal of an OR gate 258 having multiple input terminals.

OR gate 258 changes the logic level at its output terminal whenever the B1 code enters window region 76, and returns to the original logic level after the B1 code passes through the window. The final change in logic level back to the original state is used by the device as a time pulse to send a reset signal to flip-flops 232-237. The output terminal of OR gate 258 is coupled to one input terminal of NAND gate 260, which has its output terminal connected to flip-flop 262 and NAND gate 264. The output terminal of NAND gate 264 is OR gate 2
It is connected to one input terminal of a NAND gate 266 whose output terminal is connected to 68. The output terminal of OR gate 268 is coupled via NAND gate 270 to NAND gate 272 which produces a clock pulse on conductor 274. The output of OR gate 268 is the reset signal to flip-flops 232-237. The clocked pulse on lead 274 provides an output sign on lead 2 that is applied to a transducer 280 having an analog output that energizes the horizontal deflection coil 38 of image intensifier tube 10.
The quadrature latch circuit 276 generated at 78 is set.

The value of the analog voltage applied to the deflection coil 38 is sufficient to position the viewing window area 76 so that the first bar symbol again passes through the window. The output code produced by latch circuit 276 is also sent to shift register 282. Shift register 282 has an output coupled via an inverting logic circuit 284 to shift register 286 as part of a vertical deflection counter. One output terminal of register 282 is connected to NAND gates 288 and 290 to send a set pulse to the clock pulse generation logic. The output terminal of NAND gate 290 is connected to flip-flop 292. Flipflop 292 has one output conductor connected to NAND gate 294 in series with NAND gate 296 coupled to NAND gate 264. Returning to shift register 286, as mentioned above, register 286 is a vertical logic circuit and includes a counter 298 that is set by the output from shift register 286.

Shift register 286 and counter 290 are coupled to shift register 250 and counter 252, respectively, to form a composite shift register and counter. Counter 29
0 is coupled to a converter 254 to provide a vertical deflection voltage to the combination deflection coil 38 at the output of the counter 252. The output terminal of counter 298 is also connected to a quadrature latch circuit 299 which stores the previous count and sets shift register 286 to its initial level. When the bar symbol first passes through window region 76, the output of transducer 254 adjusts the position of the viewing window to center the bar symbol.

Further, the output of the converter 280 sends a signal to the deflection coil to horizontally move the observation window 76 to intensify the first bar sign and cause it to pass through the observation area of the tube 10 again. The first bar code then passes further through the window area 76 and passes through the flip-flops 232--
237 is set again to produce the code in the priority encoder 238 associated with the highest area containing the bottom portion of the bar code. This new position code allows read-only storage 2
46 and sets counter 252 to apply another deflection voltage to coil 38. During this second pass, OR gate 258 produces a horizontal deflection voltage from quadrature latch circuit 276 through converter 280 in response to the outputs of amplifiers 226-231.

Shift register 282 is again fed and advances shift register 268. Each time shift register 282 is set after the first pass, the number set in shift register 286 is decremented in the order of 16, 8, 4, 2, and 1.
In effect, in this case the deflection voltage change produced by the transducer 254 is reduced by a factor related to the number of initial passes of the rod through the viewing window. In this way the voltage output of the converter 254 to the counter 2
The influence of 98 decreases asymptotically with each pass. window area 76
If additional passes are required to center the bar symbol, the deflection coil 38 is energized to again move the window vertically and horizontally to cause the bar symbol to pass through the center of the window.

Although the logic of FIGS. 10B and 10c allows for five passes, in practice the bars are aligned after the second or third pass through the window. After adjusting the window area 76 so that the bar symbol passes through the reading area, one additional horizontal deflection is performed before beginning the reading sequence.

Passage of the bar symbol through the read zone sends the output of inverting amplifier 228 and the output of inverting amplifier 229 to the input terminal of NAND gate 301 in the logic circuit to produce a horizontal deflection signal from converter 280. With both inputs to NAND gate 301 at the same logic level, its output inhibits another horizontal positioning of window region 76 . The code is thus passed through the window and each bar is then read and detected. Once the code is properly oriented within the window, the output of flip-flop 234 sets flip-flop 300 as part of the logic circuit to provide a continuous vertical adjustment action on window area 76 to change the orientation of the document code in transport device 34. causing curvature or bending of the document;

As the full bar code moves through the reading area of window region 76, the output of comparator circuit 74 causes flip-flop 30 to pass through the reading area of window region 76.
Set 2.

The flip-flop connects its output terminal to a NAND gate 304.
is connected in series with the NAND gate 306. NAND gate 306 is connected to both input terminals of NAND gate 308 and to the input terminal of NAND gate 310. The output terminal of NAND gate 308 is connected to shift registers 250 and 286 and one input terminal of NAND gate 312. Depending on the output of comparator circuit 74, NAND gate 310 or NAND gate 312 generates a logic signal to control the vertical deflection of the window region. By the output of NAND gate 310,
Vertical deflection is set when the center of the full bar code is above the center of the reading area and must be adjusted downward. The output of the NAND gate 310 is the delay logic circuit 31
4 to a counter 298. In this case the counter 29
The count of 8 changes by one count to reduce the output of transducer 254, adjust the voltage to deflection coil 38 appropriately, and adjust the position of window region 76. If the position of the bar is low, in this case a logic signal is sent from the output terminal of NAND gate 312 to the input terminal of counter 298 via delay circuit 316 . In this case, one count is added to counters 252 and 298 to change the deflection voltage at the output terminal of converter 254 and raise window area 76. half·
As the bar code moves through the readable area of window region 76, the output of comparator 75 sets flip-flop 318 having an output terminal coupled to NAND gate 320 in series with NAND gate 306.

The half-basis logic from NAND gate 306 is the same as the full-basis logic and operates as described above. That is, each time a half bar code or a full bar code passes through the window area, the vertical position of the window is adjusted up or down according to the position of the code within the window. When all of the barcodes have passed through window region 76, a signal is applied to NOR gate 322 to produce a set signal on conductor 324, returning the device to a condition for receiving and reading another barcode.

The output of flip-flop 234 is routed to a NOR gate 328 to produce a series of logic pulses associated with the full bar code and half bar code passing through the window region 76 for each full bar code passing through the window in the read area. - Causes a change in logic level in the conductor 330 for the bar code.

The output terminal of the flip-flop 234 is connected to the delay logic circuit 33.
2, the NOR gate 3 produces an output that changes the logic level.
34, each time a half bar or full bar code passes through the window area 76. These timed pulses appear on output lead 336. Each conductor 330, 336
is connected to a visual display circuit and/or a control circuit and initiates a specific control action in response to the bar code sequence. A full bar passes through the window region each time the logic level by each conductor 330, 336 changes state. When only the logic level of conductor 336 changes state, the half bar passes through the window region. That is, only a full bar causes a logic level change in conductor 330. Resistor networks 338, 340, 342 are included in the device to maintain correct logic levels for the various components of the device of FIGS. 10A and 10B.

Each of these blocks consists of a network of parallel resistors coupled to a power supply to maintain the correct voltage levels at the unused terminals of the various logic components. This is due to standard logic circuit structure. Although the present invention has been described in detail above, specific examples of the configuration of the present invention can be summarized as follows.

It goes without saying that the present invention can be modified in various ways without departing from its spirit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a part of the main parts for generating an electric signal representing a bar code in one embodiment of the recognition device of the present invention in a perspective view, and FIG. 2 shows the main parts of the recognition device shown in FIG. 1. FIG. 3 is a diagrammatic side view of the image intensifier tube of the recognition device of FIG. 1, and FIG. 4 is a configuration diagram of another essential part of FIG. 1. FIG. 5 is a plan view of the scanning area as seen through the image intensifier tube of the recognition device of FIG. 2, and FIG. 6 is a wiring diagram of the circuit of each scanning area of FIG. FIG. 7 is a wiring diagram of an amplifier-comparator type bar-code reading device as a modification of the present recognition device, and FIG. 8 is a wiring diagram of an additional amplifier of the amplifier-comparator Q shown in FIG. FIG. 9 is a wiring diagram of the amplifier-comparator bar code reader for scanning areas 3, 4V, and 4L; FIGS. 10A and 10B are wiring diagrams of the receiving, tracking, and reading logic of FIG. It is. 10... Image intensification tube, 12... Code, 18... Optical fiber bundle, 20... Photosensitive sensor, 22... Recognition Logic circuit, 32...Target, 38...
- Deflection coil, 40... Phosphor screen, 64... Image deflection circuit network, 68, 69
, 70, 71, 72, 73, 74, 75... comparator circuit, 80, 82... amplifier.

Claims (1)

[Claims] 1 A recognition device for reading and tracking encoded data carried by a target and moving with respect to a reading location, the reading location having a coded image area, a background area on the left, and a background area on the right. a plurality of vertically disposed code regions, each having a ground area; a left background image signal from each code area; and a left background image signal from each code area; In a recognition device provided with a receiving and supplying means for supplying a signal and a background image signal on the right side, (a) a signal reflected from the encoded data to an arbitrary code region among the plurality of code regions; (b) a control circuit connected to the deflection means for varying the amount of deflection imparted to the reflected energy; (c) a control circuit connected to the deflection means for varying the amount of deflection applied to the reflected energy; (d) signal generating means coupled to the supply means for generating an electrical signal responsive to and associated with each of the three signals from each of said code regions; and (d) within a designated portion of said receiving and supply means. (e) a circuit connected to receive the electrical signal and generate a variable control voltage to the control circuit to maintain the code image area in the code image area; a comparator for each said code region, for comparing an electrical signal associated with said region with an electrical signal associated with said code image region, and generating from this comparison a series of code-related pulses representative of said encoded data; A recognition device comprising: