JP3793286B2 - Symbol reader - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a symbol reader for reading data symbols such as a two-dimensional barcode reader.
[0002]
[Prior art]
Conventionally, as an MMF (man machine interface) compatible with POS (Point of Sales) systems, etc., product information in a barcode format is printed on the product body or package, and the barcode is read by a reader such as a barcode reader. A system that reads product information recorded on the computer and transmits it to a host computer is widely used. In recent years, such a system has a two-dimensionally encoded pattern instead of a method of reading a one-dimensional barcode symbol with a line sensor in accordance with an increase in the amount of information given to the barcode. A method of reading a dimensional data symbol by a two-dimensional area sensor has begun to spread. In order to accurately read the two-dimensional data symbol with the two-dimensional area sensor, the two-dimensional data symbol must be accurately positioned in the reading opening of the barcode reader and imaged on the two-dimensional area sensor.
[0003]
[Problems to be solved by the invention]
However, even if the two-dimensional data symbol is positioned in the reading aperture, the reading aperture is significantly separated from the plane (hereinafter referred to as “symbol plane”) on which the two-dimensional data symbol is formed due to the hand shake of the operator or the like. There may be a case where the distance between the symbol surface and the reading opening is not uniform due to the reader housing being tilted. The photographic optical system provided in the case of the barcode reader allows a two-dimensional data symbol to be imaged on the two-dimensional area sensor when the symbol surface is brought into contact with the wall surface of the case where the reading opening is formed. Therefore, if the reading operation is performed in the above-described state, the image formed on the two-dimensional area sensor is blurred or distorted, and the two-dimensional data symbol cannot be read accurately.
[0004]
An object of the present invention is to solve the above problems, and to stably read a two-dimensional data symbol.
[0005]
In this specification, the “symbol plane” refers to a plane including a two-dimensional data symbol positioned in the opening of the symbol reader, and “symbol reading” refers to the plane positioned in the reading aperture. This refers to the processing from image capturing until image information of a two-dimensional data symbol is extracted and decoded.
[0006]
[Means for Solving the Problems]
A symbol reading apparatus according to the present invention is a symbol reading apparatus that reads a symbol by positioning a symbol surface on which a coded symbol is formed on one wall surface of a housing and positioning the symbol in a reading opening provided on the wall surface. A symbol reading means for optically reading the symbol, and a contact sensing means provided on the wall surface for sensing the contact state between the symbol surface and the wall surface. The contact sensing means has a plurality of spaced sensing elements. When all the sensing elements sense contact, the symbol reading means performs a reading operation.
[0007]
A symbol reading apparatus according to the present invention is a symbol reading apparatus that reads a symbol surface on which a coded symbol is formed facing a wall surface of a housing and positions the symbol in a reading opening provided on the wall surface. , A means for imaging the symbol surface, a means for extracting symbol information from information captured by the imaging means, and a contact sensing means provided on the wall surface for sensing the contact state between the symbol surface and the wall surface. The means has a plurality of spaced sensing elements, and the imaging means or the symbol information extracting means is driven based on a combination of sensing states of the sensing elements.
[0008]
The imaging means is preferably driven when one of the sensing elements senses contact with the symbol surface.
[0009]
The symbol extraction means is preferably driven when all of the sensing elements sense contact with the symbol surface.
[0010]
The sensing element is provided, for example, at a point-symmetrical position with respect to the center of the reading opening.
[0011]
The reading aperture is preferably square and two sensing elements are provided on the diagonal extension of the reading aperture.
[0012]
The sensing element is, for example, an on / off switch that maintains an on state while being energized by a pressing force and maintains an off state while not energizing by the pressing force.
[0013]
The sensing element is preferably provided with a non-slip member.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a symbol reading apparatus according to an embodiment of the present invention. The housing 10 includes a head portion 10a and a grip portion 10b. The bottom surface 11 is one wall surface of the head portion 10a in which a rectangular reading opening 12 is formed. A first switch 13 and a second switch 14 are provided on the bottom surface 11 in the vicinity of the reading opening 12. The first switch 13 and the second switch 14 are disposed so as to be point-symmetric with respect to the center of the reading opening 12 and on a diagonal line connecting the corners of the reading opening 12. The first switch 13 and the second switch 14 are self-returning type on / off switches, which are turned on when the front end portion and the bottom surface 11 become uniform when pressed. In addition, for example, a rubber anti-slip member is provided at the tip. A trigger 15 for starting a reading operation is provided on the side surface of the grip portion 10b. Further, a cable 16 for transmitting the reading result to an external device (not shown) such as a host computer is attached to the end of the gripping part 10b opposite to the head part 10a.
[0015]
FIG. 2 is a block diagram of the symbol reading apparatus according to the present embodiment.
A CPU (Central Processing Unit) 20 controls the entire symbol reader. The first switch 13 is connected to a NOR circuit 51, which is a logic circuit, an OR circuit 52, and an AND circuit 53 via an inverter 13a, and the second switch 14 is connected to the NOR circuit 51, an OR circuit via an inverter 14a. 52 and the AND circuit 53. The output signal of the NOR circuit 51 is input to the port P ₁ of the CPU 20, the output signal of the OR circuit 52 is input to the port P ₂ , and the output signal of the AND circuit 53 is input to the port P ₃ . Further, the trigger 15 is connected to the inverter 15a, the output signal of the inverter 15a is input to the port P _SW of CPU 20.
[0016]
The CPU 20 is connected to each circuit constituting the imaging circuit 30, that is, a power supply circuit 31, a CCD drive circuit 32, a light source drive circuit 33, and a signal processing circuit 34. A power supply circuit driving signal for controlling the power supply circuit 31 is output from the port P _EN /, and power is supplied from the power supply circuit 31 to the CCD 35 and other circuits of the imaging circuit 30 according to the output signal. Control signals for the CCD drive circuit 32 and the light source drive circuit 33 are output from ports S ₁ and S ₂ , respectively. The power supply circuit drive signal is an active low signal that causes the power supply circuit 31 to supply power to various circuits when it is low (L).
[0017]
The light source 36 is driven according to the control signal output from the light source driving circuit 33, the illumination light is irradiated on the symbol surface, and the reflected light of the symbol surface is imaged on the CCD 35. The CCD 35 is driven according to the control signal output from the CCD driving circuit 32. Then, the optical image of the symbol surface is photoelectrically converted. The photoelectrically converted symbol plane image information output from the CCD 35, that is, all pixel data is output to the monitor 37 via the monitor display circuit 39. The monitor 37 is provided, for example, on the upper surface of the housing 10 (not shown). Therefore, the operator can visually check the state of the reading opening by the image displayed on the monitor 37. Further, all pixel data is outputted to the monitor 37, the signal processing circuit 34 is subjected to binarization processing and the like are input to the port P _4. From the CCD driving circuit 32 is input to the port P ₅ is output synchronizing signal used for the extraction of the symbol information. The CPU 20 stores all pixel data input to the port P ₄ in a memory (not shown) based on the synchronization signals (vertical, horizontal synchronization signal, and field index signal FI) input to the port P ₅ .
[0018]
Further, the CPU 20 extracts and extracts symbol information from the symbol plane image information stored in the memory based on the synchronization signal (vertical, horizontal synchronization signal, and field index signal FI) input to the port P _5. Processing such as decoding is performed based on the symbol information. The symbol information that has been successfully decoded is output from the port P ₆ and transmitted to the host computer via the external interface 38.
[0019]
Next, the control processing of the imaging circuit 30 in the CPU 20 according to the state of the first switch 13 and the second switch 14 will be described using the truth table 1 of FIG. In truth table 1, the values of the switches and ports P ₁ , P ₂ , and P ₃ are low signals that 0 indicates a low voltage, and 1 is a high signal that indicates a high voltage. The value of the port P _EN / is 0, which means low, a value for turning on the power supply circuit 31 and operating, and 1, which means high, indicating a value for turning off the power supply circuit 31 and inactivating it.
[0020]
The first row of the truth table 1 shows the values of the respective ports in a state where both the first switch 13 and the second switch 14 are turned off. When the first switch 13 and the second switch 14 are not pressed, a high voltage is input to the inverters 13a and 14a, and a low signal is output from the inverters 13a and 14a, so that a NOR circuit 51, an OR circuit 52, and an AND circuit 53. Therefore, the signal output from the NOR circuit 51 and input to the port P ₁ is high, the signal output from the OR circuit 52 and input to the port P ₂ is low, and the signal output from the AND circuit 53 is input to the port P _3. The signal goes low.
[0021]
The second row of the truth table 1 shows the values of the respective ports in the state where the first switch 13 is turned on and the second switch 14 is turned off. A high signal is output from the first inverter 13a and input to each logic circuit, and a low signal is output from the second inverter 14a and input to each logic circuit. Therefore, the signal input from the NOR circuit 51 to the port P ₁ is low, the signal output from the OR circuit 52 and input to the port P ₂ is high, and the signal output from the AND circuit 53 and input to the port P ₃ is Become low.
[0022]
The third row of the truth table 1 shows the values of the respective ports in the state where the first switch 13 is turned off and the second switch 14 is turned on. A low signal is output from the first inverter 13a and input to each logic circuit, and a high signal is output from the second inverter 14a and input to each logic circuit. Therefore, the signal input from the NOR circuit 51 to the port P ₁ is low, the signal output from the OR circuit 52 and input to the port P ₂ is high, and the signal output from the AND circuit 53 and input to the port P ₃ is Become low.
[0023]
The fourth row of the truth table 1 shows the values of the respective ports in a state where both the first switch 13 and the second switch 14 are turned on. When the first switch 13 and the second switch 14 are pressed, a low signal is input to the inverters 13a and 14a, and a high signal is output from the inverters 13a and 14a to output a NOR circuit 51, an OR circuit 52, and an AND circuit. 53. Therefore, the signal output from the NOR circuit 51 and input to the port P ₁ is low, the signal output from the OR circuit 52 and input to the port P ₂ is high, and is output from the AND circuit 53 and input to the port P _3. The signal goes high.
[0024]
The value of port P _EN / is determined by the value of port P ₁ . When the value of the port P ₁ is high, the value of the port P _EN / is high (1), and when the value of the port P ₁ is low, the value of the port P _EN / is low (0). The value of the port P ₁ becomes high only when both the first switch 13 and the second switch 14 are off as described above. That is, when both the first switch 13 and the second switch 14 are off, the power supply circuit 31 is not driven, and therefore the other circuits of the imaging circuit 30, the CCD drive circuit 32, the light source drive circuit 33, and the signal processing circuit 34 Since it is not driven, the imaging process of the symbol plane is not performed. On the other hand, when at least one of the first switch 13 and the second switch 14 is pressed, the power supply circuit 31 is driven, the imaging circuit 30 is driven accordingly, and the symbol plane imaging process is started. The
[0025]
FIG. 4 is a processing flow from imaging processing of the symbol surface to transmission of symbol data.
At the start of the processing flow, the power source of the symbol reader main body is turned on, and the CPU 20 is in an operating state. In step 100, the port P _EN / is initialized and the output value is set to 1. That is, in step 100, the power supply of the imaging circuit 30 is turned off.
[0026]
In step 101, it is determined whether or not the trigger switch 15 is pressed (whether it is turned on). If not, the process proceeds to step 102. If it is pressed (turned on), the process proceeds to step 103. The port P _EN / is set to 0, the power of the imaging circuit 30 is turned on, the symbol plane is imaged, and the binarization processing or predetermined image processing is performed on the image information of the symbol plane read out by imaging. After that, it is stored in the memory, and the process proceeds to Step 108.
[0027]
Value of the port P ₁ in step 102 is confirmed, 0 or first switch 13, at least one of the second switch 14 proceeds to step 104 if it is on, unless the step 100 is also turned on both switches Returning, the power supply of the imaging circuit 30 is turned off. In step 104, the port P _EN / is set to 0, the imaging circuit 30 is turned on, the symbol plane is imaged, and the symbol plane image information read out by the imaging is binarized or predetermined image processed. Is stored in the memory and the process proceeds to step 105.
[0028]
In step 105, it is determined whether or not the trigger 15 is pressed as in step 101. If not, the process proceeds to step 106, and if it is pressed, the process proceeds to step 108.
[0029]
Value of the port P ₁ in step 106 is confirmed, 0 or first switch 13, the process proceeds to step 107 if left at least one of the ON state of the second switch 14, the value of the port P ₁ is 1 i.e. If both switches are off, the process returns to step 100 and the power of the imaging circuit 30 is turned off. In step 107, the values of the port P ₂ and the port P ₃ are confirmed. If both are 1, that is, if both the first switch 13 and the second switch 14 are on, the process proceeds to step 108. If the value of either port P ₂ or port P ₃ is 0, or if both ports are both 0, the process returns to step 105.
[0030]
In step 108, symbol extraction processing, that is, processing for reading out image information of the symbol plane from the memory and extracting only pixel data corresponding to the symbol from the image information is performed. Next, at step 109, decoding processing is performed based on the pixel data extracted at step 108. If the decoding process is successful, the symbol information decoded in step 110 is transmitted to an external host computer as a successful symbol reading. If the decoding process fails, transmission to the host computer is not performed. The symbol reading result is notified to the operator by a buzzer or a display lamp (not shown) provided on the housing.
[0031]
As described above, in this embodiment, when only one of the first switch and the second switch is turned on, the value of the port P _EN / is only set to 0. That is, the imaging process of the symbol surface is performed in the imaging circuit 30, only the binary data symbol surface is input to the port P ₄ of the CPU 20, the extraction processing of the symbol is not performed. Accordingly, since either the first switch 13 or the second switch 14 is in the on state, the imaging circuit rises and the symbol plane is displayed on the monitor 37, so that the operator can visually check the status of the symbol plane and the both switches are in the on state. It is possible to prevent the symbols from being out of the reading aperture until the symbol extraction process is performed while holding.
[0032]
When both the first switch 13 and the second switch 14 are in the on state, symbol extraction processing is performed assuming that proper reading is possible, and the extracted symbol data is decoded.
[0033]
In the present embodiment, the first switch 13 and the second switch 14 are switches that are positioned on the diagonal line of the rectangular reading opening 12 and are turned on when the leading end becomes uniform with the bottom surface 11 when pressed. is there. Accordingly, by holding both switches in the ON state, the reading opening 12 is closely attached and fixed to the symbol surface, so that camera shake is easily prevented and the symbol image formed on the CCD 35 is blurred or distorted. The phenomenon can be avoided.
[0034]
Further, the first switch 13 and the second switch 14 may be provided on the diagonal line of the reading opening 12 by using a switch that is turned on only by being pushed even if the tip portion is not uniform with the bottom surface 11. . By operating the bar code reader while both switches are kept on, the bar code reader will swing in the direction about the diagonal line even if hand shake occurs. Since the corner portions other than the corner portion where the switch 14 is disposed are in contact with the symbol surface, the inclination of the bar code reader is extremely low, and the symbol image formed on the CCD 35 is blurred or distorted. The phenomenon is minimized.
[0035]
Further, in the present embodiment, the number of switches is two (first switch) in order to avoid that each process such as decoding in the CPU 20 becomes complicated as the number of switches provided on the bottom surface 11 increases, and the rapid data processing cannot be performed. 13 and the second switch 14), and the effect obtained by arranging the above-described switches on the diagonal line of the reading aperture is realized with the smallest number of switches.
[0036]
In addition, since the first switch 13 and the second switch 14 are provided at positions that are point-symmetric with respect to the center of the reading opening 12, the bottom surface 11 of the head portion 10a can be obtained by turning both switches on. Therefore, it is possible to prevent the reading opening from being easily fixed with respect to the symbol surface.
[0037]
Further, in order to prevent the case once fixed from sliding on the symbol surface while the first switch 13 and the second switch 14 are on, the tips of the first switch 13 and the second switch 14 Is provided with a rubber member.
[0038]
Therefore, the symbol plane image information output from the imaging optical system is not disturbed. For this reason, it is possible to prevent the symbol position on the symbol plane from being specified or to extract erroneous symbol information, and the symbol information can be extracted stably.
[0039]
Furthermore, since the image pickup circuit starts up with either the first switch 13 or the second switch 14 pressed, the symbol extraction process can be started almost simultaneously with the pressing of both switches. , Processing time is shortened.
[0040]
In the present embodiment, the switches are provided at two positions, but the present invention is not limited to this, and it is only necessary to provide a plurality of positions at point symmetrical positions with respect to the center of the reading opening.
[0041]
In this embodiment, rubber members are provided at the tips of the first switch 13 and the second switch 14, but the present invention is not limited to this, and it is possible to prevent each switch from sliding on the symbol surface. Anything is possible.
[0042]
【The invention's effect】
As described above, according to the present invention, when a symbol such as a two-dimensional barcode is read, an operator's hand shake is prevented, so that the symbol extraction process can be performed stably.
[Brief description of the drawings]
FIG. 1 is a perspective view of a symbol reading apparatus according to the present invention.
FIG. 2 is a block diagram of a symbol reading apparatus according to the present invention.
FIG. 3 is a truth table of arithmetic processing in a CPU built in the symbol reading device.
FIG. 4 is a processing flow of symbol reading in the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Case 12 Reading opening part 13 1st switch 14 2nd switch 15 Trigger 20 CPU
30 Imaging circuit

Claims (7)

  A symbol reading device that reads a symbol surface on which a coded symbol is formed facing a wall surface of a housing and positions the symbol in a reading opening provided on the wall surface, and means for imaging the symbol surface; A means for extracting the information of the symbol from the imaging information obtained by the imaging means; and a contact sensing means provided on the wall surface for sensing the contact state between the symbol surface and the wall surface. The symbol reading device is characterized in that the imaging means or the symbol information extraction means is driven based on a combination of sensing states of the sensing elements. The symbol reading apparatus according to claim 1 , wherein the imaging unit is activated when one of the sensing elements senses contact with the symbol surface. 2. The symbol reading apparatus according to claim 1 , wherein the symbol information extracting unit is driven when all of the sensing elements sense contact with the symbol surface. The symbol reading device according to claim 1 , wherein the sensing element is provided at a point-symmetrical position with respect to a center of the reading opening. The symbol reading apparatus according to claim 4 , wherein the reading opening is a quadrangle, and two sensing elements are provided on a diagonal line of the reading opening. 6. The on / off switch according to claim 5 , wherein the sensing element is an on-off switch that maintains an on-state while being energized by a pressing force and maintains an off-state while not energizing by the pressing force. Symbol reader. The symbol reading device according to claim 6 , wherein the sensing element is provided with a non-slip member.

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