JP2009099099A - Optical information reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a configuration capable of excellently reading the image of a bar code with high accuracy even under a situation where the image of the bar code image-formed by a light receiving sensor becomes small. <P>SOLUTION: A bar code reader is provided with: the light receiving sensor provided with an element string with a plurality of light receiving elements arranged in a predetermined direction; an image-forming lens causing the light receiving sensor to image-form reflected light from the bar code; and a generating means for generating a plurality of pieces of waveform data including reflection level data of a plurality of positions in the bar arrangement direction of the bar code on the basis of respective optical signals from the plurality of light receiving elements constituting the element string. The bar code reader is further provided with a waveform synthesizing means for synthesizing the generated plurality of pieces of waveform data while aligning the waveform data, and generating a single synthesized waveform data in which the plurality of pieces of waveform data are reflected, and the bar code reader decodes the synthesized waveform data generated by the waveform synthesizing means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical information reader.

In the field of barcode readers, a configuration that can read a farther barcode is desired for reasons such as convenience. In Patent Document 1, a problem in reading a barcode placed far away is solved. A technique for reading a distant bar code well has been disclosed.
JP-A-8-320908

  As the barcode becomes far away, the barcode image formed on the light receiving sensor (for example, CCD sensor) becomes smaller, so the number of light receiving elements assigned to each bar (that is, the number of assigned pixels) decreases. As described above, when the number of light receiving elements assigned to each bar decreases, there is a problem that it becomes difficult to obtain image data that accurately reflects the barcode image, and as a result, the reading accuracy decreases. As a countermeasure for such a problem, a method of increasing the number of pixels of the sensor is conceivable. However, there is a concern that the reception of the received light signal may take a long time or the cost of the apparatus increases.

  In Patent Document 1, in order to solve such a problem, a concave mirror is arranged on the path of reflected light, and the concave mirror reduces the angle of view of the reflected light from the barcode, thereby forming an imaging magnification in the light receiving sensor. Is increased so that more pixels are allocated to each bar. However, the configuration of Patent Document 1 has a problem that the reading field is easily narrowed and it is difficult to read a wide barcode or a large-size barcode. Further, there is a problem in that the barcode image is distorted due to the influence of the concave mirror.

  The present invention has been made to solve the above-described problems, and is capable of reading with high accuracy and good even under a situation where the barcode image formed by the light receiving sensor is small. The purpose is to provide.

  In order to achieve the above object, a first aspect of the present invention is a light receiving sensor including an element array in which a plurality of light receiving elements are arranged in a predetermined direction, and an imaging lens that forms an image of reflected light from a barcode with the light receiving sensor. And generating means for generating a plurality of waveform data including reflection level data at a plurality of positions in the bar arrangement direction of the bar code based on the light receiving signals from the plurality of light receiving elements constituting the element row, and the generation A plurality of the waveform data generated by the means are synthesized while being aligned, and a waveform synthesis means for generating a single synthesized waveform data reflecting the plurality of waveform data, and the waveform synthesis means generated by the waveform synthesis means And decoding means for performing decoding processing based on the combined waveform data.

  According to a second aspect of the present invention, in the optical information reading device according to the first aspect, the light receiving sensor is an area sensor in which a plurality of the element rows are arranged in a direction orthogonal to the predetermined direction, and the generating means A plurality of the waveform data are generated based on the light reception signals from the plurality of element rows in the area sensor.

  According to a third aspect of the present invention, in the optical information reading device according to the first or second aspect, the generation unit supplements an intermediate position shifted from the plurality of positions based on the reflection level data of the plurality of positions. Interpolation data is generated, and the waveform data is constituted by the reflection level data at the plurality of positions and the interpolation data at the intermediate position, and the waveform synthesis means is configured to generate the waveform data including the interpolation data. The composite waveform data is generated by combining a plurality of the waveform data.

  According to a fourth aspect of the present invention, in the optical information reading apparatus according to any one of the first to third aspects, the waveform synthesizing unit uses any one of the plurality of waveform data as reference waveform data, and Each of the other waveform data is aligned with each reference level data and synthesized with respect to the reference waveform data.

  According to a fifth aspect of the present invention, in the optical information reading device according to any one of the first to fourth aspects, the waveform data is in a predetermined similar state to any one or a plurality of other waveform data. Similarity determining means for determining whether or not the waveform data is determined, and the waveform synthesizing means excludes the waveform data determined to be not in the predetermined similar state by the similarity determining means from synthesis targets.

  According to the first aspect of the present invention, a plurality of waveform data including reflection level data at a plurality of positions in the bar arrangement direction of the barcode is generated, and the plurality of waveform data are synthesized while being aligned, and the plurality of waveform data are combined. A single composite waveform data that is reflected is generated. In this way, it is possible to obtain waveform data that reflects the barcode bar array with higher accuracy, and to perform good decoding processing based on such waveform data.

  In the invention of claim 2, a plurality of element rows of the light receiving sensor are arranged in a direction orthogonal to the row direction (predetermined direction) of the element row, and a plurality of waveform data are obtained based on light receiving signals from the plurality of element rows. Is generated. In this way, a plurality of waveform data can be quickly generated, and since the waveform acquisition positions are different, it is possible to generate combined waveform data in which the influence of noise is reduced. In addition, since the light receiving element rows are arranged in a direction orthogonal to the row direction of the element rows, the waveform data can be aligned quickly and satisfactorily.

  In the invention of claim 3, when generating the waveform data, the interpolation data for generating the intermediate position deviating from the plurality of positions (reflection level data acquisition position) is generated based on the reflection level data at the plurality of positions. Waveform data is constituted by the reflection level data of the position and the interpolation data of the intermediate position. If the composite waveform data is generated after composing the waveform data obtained by interpolating the intermediate position with the interpolation data in this way, it is possible to perform the synthesis with appropriate consideration of the intermediate position other than the reflection level data acquisition position. The combined waveform data reflecting the barcode with higher accuracy can be generated.

  According to the fourth aspect of the present invention, any one of the plurality of waveform data is used as the reference waveform data, and the other waveform data is aligned with the reference waveform data for each reflection level data and synthesized. In this way, the synthesis process can be performed quickly and suitably.

  According to the invention of claim 5, it is determined whether or not the waveform data to be synthesized is in a predetermined similar state with any one or a plurality of other waveform data, and the waveform data determined not to be in the predetermined similar state Is excluded from the synthesis target. In this way, dissimilar waveform data that should not be synthesized (for example, waveform data that is dissimilar due to contamination or the like) can be removed.

[First embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment in which an optical information reading device of the invention is embodied will be described with reference to the drawings. FIG. 1 is a block diagram schematically illustrating an electrical configuration of a barcode reader according to the first embodiment of the present invention.

  A bar code reader 10 shown in FIG. 1 corresponds to an example of the optical information reading apparatus of the present invention, and reads a bar code attached to an article (in FIG. 1, the bar code B attached to the article R is illustrated). It is configured as a device. The barcode reader 10 is configured by housing a circuit unit 20 in a case (not shown). The circuit unit 20 mainly includes an optical system such as an illumination light source 21, a light receiving sensor 28, and an imaging lens 27. , A memory 35, a control circuit 40, a trigger switch 42, and other microcomputer (hereinafter referred to as “microcomputer”) systems.

  The optical system is divided into a light projecting optical system and a light receiving optical system. The illumination light source 21 constituting the light projecting optical system functions as an illumination light source capable of emitting the illumination light Lf, and includes, for example, a red LED and a lens provided on the emission side of the LED. Note that FIG. 1 conceptually shows an example in which the illumination light Lf is irradiated toward the reading object R to which the barcode B is attached.

  The light receiving optical system includes a light receiving sensor 28, an imaging lens 27, a reflecting mirror (not shown), and the like. The light receiving sensor 28 is configured as a CCD area sensor, and is configured to receive the reflected light Lr irradiated and reflected on the reading object R and the barcode B. The light receiving sensor 28 is mounted on a printed wiring board (not shown) so as to be able to receive incident light incident through the imaging lens 27.

  The imaging lens 27 functions as an imaging optical system capable of condensing incident light incident from the outside via a reading port (not shown) and forming an image on the light receiving surface 28a of the light receiving sensor 28. . In the present embodiment, the reflected light Lr obtained by reflecting the illumination light Lf emitted from the illumination light source 21 by the barcode B is collected by the imaging lens 27 and a code image is formed on the light receiving surface 28 a of the light receiving sensor 28. I am letting you image.

  The microcomputer system includes an amplification circuit 31, an A / D conversion circuit 33, a memory 35, an address generation circuit 36, a synchronization signal generation circuit 38, a control circuit 40, a trigger switch 42, a buzzer 44, a display LED (hereinafter also simply referred to as an LED). 45, a liquid crystal display 46, a communication interface 48, and the like.

  The image signal (analog signal) output from the light receiving sensor 28 of the optical system is amplified by a predetermined gain by being input to the amplifier circuit 31, and then input from the analog signal when input to the A / D conversion circuit 33. Converted into a digital signal. When the digitized image signal, that is, image data (image information) is input to the memory 35, it is stored in a predetermined code image image information storage area. The synchronization signal generation circuit 38 is configured to generate a synchronization signal for the light receiving sensor 28 and the address generation circuit 36, and the address generation circuit 36 is based on the synchronization signal supplied from the synchronization signal generation circuit 38. Thus, the storage address of the image data stored in the memory 35 can be generated.

  The control circuit 40 is configured by a microcomputer that can control the entire barcode reader 10, has a CPU, a system bus, an input / output interface, and the like, has an information processing function, and constitutes an information processing apparatus together with the memory 35. is doing. In the present embodiment, a trigger switch 42, a buzzer 44, an LED 45, a liquid crystal display 46, a communication interface 48, and the like are connected to the control circuit 40. For example, monitoring and management of the trigger switch 42, beep sounds and alarm sounds. The control circuit 40 performs on / off of the ringing of the buzzer 44 capable of generating noise, lighting and non-lighting of the LED 45, display control of the liquid crystal display 46, control of the communication interface 48, and the like. The control circuit 40 corresponds to an example of “generation means”, “waveform synthesis means”, “decode means”, and “similarity determination means”.

  Next, reading processing by the barcode reader 10 will be described. FIG. 2 is a flowchart illustrating the flow of the reading process. FIG. 3 is a flowchart illustrating the flow of waveform data synthesis processing. FIG. 4A is an explanatory diagram for explaining the relationship between the element configuration of the light receiving sensor 28 and the barcode image formed on the light receiving sensor 28, and FIG. 4B is a diagram of FIG. 4A. It is explanatory drawing which shows the image data obtained based on a barcode image.

  With the start of the reading process in FIG. 2, first, a range specifying process (labeling process) is performed (S1). In this range specifying process, image data of the barcode B as shown in FIG. 4B is generated based on the light reception result of the light receiving sensor 28, and then the barcode area A1 is specified in the image data. In the light receiving sensor 28 of the present embodiment, as shown in FIG. 4A, a plurality of light receiving elements are arranged in a predetermined direction (in this embodiment, the width direction of the barcode reader 10, and in FIG. 4A, the horizontal direction in the drawing). A plurality of element rows are provided. A plurality of these element arrays are arranged in a direction (vertical direction in FIG. 4A) orthogonal to the predetermined direction (element array arrangement direction), and are configured as an area sensor as a whole. When reading the barcode B, the image B ′ of the barcode B is formed on the light receiving sensor 28 by the imaging lens 27. Each light receiving element of the light receiving sensor 28 outputs a light receiving signal reflecting such a barcode image B ′. In the process of S1, based on the light receiving result of the light receiving sensor 28. Image data as shown in FIG. 4B is generated. Further, as shown in FIG. 4B, in the generated image data, the barcode area A1 is specified in such a manner that a predetermined margin area is provided around the arrangement area of the black bar and the white bar.

After specifying the barcode area A1 in S1, processing for generating waveform data is performed in S2. This waveform data generation process is a process of selecting a plurality of positions in the barcode area A1 specified by the range specifying process of S1 and generating waveform data for these plurality of positions. Specifically, a plurality of element rows arranged in the image formation region of the barcode image B ′ in the light receiving sensor 28 are selected, and waveform data for each element row is obtained based on the light reception signals from the plurality of element rows. Generate each. In this way, the waveform data is constituted by the reflection level data at a plurality of positions in the bar arrangement direction of the barcode B.
In the present embodiment, the control circuit 40 and the program shown in FIG. 2 correspond to an example of “generating means”.

  In this embodiment, as shown in FIG. 4B, waveform data is generated for five positions L1 to L5 including the center position in the barcode area A1 of the image data. The five positions L1 to L5 are five element rows L1 ′ to L5 arranged in the imaging region A1 ′ of the barcode image B ′ in the light receiving sensor 28 (element region for generating an image of the barcode region A1). (Refer to FIG. 4A), and in the process of S2, the received light amount for each light receiving element in each of the five element rows L1 'to L5' is obtained, and the position data for each light receiving element and The waveform is stored in the memory 35 in a state in which the received light amount is associated. FIG. 5A illustrates the waveform data of one element array arranged in the imaging area of the barcode image, and the horizontal axis corresponds to the light receiving position (in FIG. 5A, the position corresponds to the position of each light receiving element). ), The vertical axis indicates the amount of received light, and the relationship between the light receiving position and the amount of received light in the light receiving sensor 28 is shown as waveform data. In the present embodiment, the position data of each light receiving element constituting the element array corresponds to a plurality of positions in the bar array direction in the barcode B, and the amount of light received by each light receiving element constituting the element array is It corresponds to each reflection level data at a plurality of positions.

After generating waveform data in S2, interpolation processing is performed for each waveform data (S3).
This interpolation processing is based on the reflection level data at a plurality of positions of the barcode B (that is, the received light amount for each light receiving element corresponding to the plurality of positions in the bar arrangement direction of the barcode B). This is a process of generating interpolation data to be supplemented and regenerating waveform data from the reflection level data at the plurality of positions and the generated interpolation data at the intermediate position. Specifically, as shown in FIG. 5B, by generating new received light amount data for an intermediate position between two adjacent light receiving element positions, the light receiving position data in the light receiving sensor 28 is further subdivided. And the number of data is doubled.

  For example, in FIGS. 4A and 4B, when the number of elements in the horizontal direction in the imaging area A1 ′ corresponding to the barcode area A1 is 100, position data for these 100 elements is used in the process of S2. Waveform data as shown in FIG. 5A is configured by associating the (light receiving position in the light receiving sensor 28) with the amount of light received. In FIG. 5A, the value of the light receiving position is determined in the arrangement order of the elements from one end side in each element row, and the value of the light receiving position corresponding to the element arranged at the end of each element row is “ The value of each light receiving position is determined so that the value of the light receiving position corresponding to the element disposed second is “2”. In the process of S3, the received light amount data for the intermediate position shifted from each light receiving position specified by the 100 light receiving elements is estimated and generated, and the light receiving for each light receiving element as shown in FIG. 5B. Waveform data having twice the number of data is regenerated by the amount data and the received light amount estimation data for each intermediate position. In FIG. 5B, “position corresponding to each light receiving element constituting the element row” (that is, each light receiving position shown in FIG. 5A) and “intermediate position shifted from the position corresponding to each light receiving element”. "(That is, a light receiving position newly determined in addition to FIG. 5A) reconfigures the" light receiving position ". Each light receiving position (that is, a position corresponding to each light receiving element constituting the element row) in FIG. 5A is 1, 2, 3, 4, 5,... This corresponds to odd numbers such as 1, 3, 5, 7, and 9, and the even-numbered light receiving positions in FIG. 5B correspond to intermediate positions added thereto.

  FIG. 6 is an enlarged view of a partial area (specifically, the left end area) of the waveform data generated in S2, and shows the correspondence between the light receiving position and the amount of light received in the light receiving sensor as a graph. . FIG. 6B shows an example in which interpolation processing is performed on the waveform data of FIG. 6A, and waveform data including the interpolation data is regenerated. In the present embodiment, the amount of light received for each light receiving element is obtained as shown in FIG. 6A, and then interpolation data is obtained for each two adjacent light receiving elements. Specifically, the center position of two adjacent light receiving elements in the column direction of the element row is defined as an “intermediate position”, and the average value of the amounts of light received by the two adjacent light receiving elements is received at the “intermediate position”. Interpolation data is constituted by the position data of each intermediate position and the light reception amount estimated value at each intermediate position as the amount estimated value. For example, the light receiving amount of the first light receiving element (the light receiving position value is “1” in FIG. 6A) is 110, and the light receiving position value is “2” in the second light receiving element (FIG. 6A). ) Is 105, the center position of the two adjacent light receiving elements (that is, the position of 1.5) becomes the “intermediate position”, and the light reception average value of the two adjacent light receiving elements ( That is, the value of 107.5) is the estimated received light amount at the “intermediate position”. In this way, the estimated amount of received light at each intermediate position is sequentially obtained. In the example of FIG. 6B, after the interpolation data is generated as described above, the value of the light receiving position after the first light receiving position is doubled, and the value of each light receiving position is represented by an integer. . In S3, such an interpolation process is performed on all the waveform data obtained in S2.

Next, synthesis processing of waveform data is performed (S4). This waveform data synthesis process is performed in S2, S3.
A plurality of waveform data generated by the above processing (that is, waveform data after interpolation processing including interpolation data) is synthesized while being aligned, and a single composite waveform data reflecting the plurality of waveform data is generated. It is processing to do. In the present embodiment, the control circuit 40 and the program shown in FIG. 3 correspond to an example of “waveform synthesis means”.

  In the waveform data synthesis process exemplified in this embodiment, any one of a plurality of waveform data obtained in S2 and S3 is used as reference waveform data, and other waveform data is converted to each reflection level with respect to the reference waveform data. The data is combined for each data (that is, for each received light amount data). As shown in FIG. 3, with the start of the process, first, a process of determining reference waveform data from a plurality of waveform data after the interpolation process is performed (S41). Here, the waveform data obtained by the element row L1 ′ closest to the center of the imaging area A1 ′ of the barcode image B ′ is used as the reference waveform data.

  Thereafter, one waveform data to be synthesized with the reference waveform data is selected (S42). In the present embodiment, after the reference waveform data is determined, the waveform data from the element array on one side in the vertical direction is synthesized sequentially, and the waveform data obtained by the element array L2 ′ is selected immediately after the processing of S41. Is done.

  For example, when the waveform data shown in FIG. 5B is the reference waveform data and the waveform data shown in FIG. 7A is the first waveform data to be synthesized selected in S42, these are simply used. When superimposed, the result is as shown in FIG. In the process of S43, the two different waveform data are synthesized while being aligned, and one waveform data reflecting both the waveform data is generated.

  Specifically, first, the waveform data (first time) to be synthesized for the received light amount data at all positions of the waveform data to be synthesized (hereinafter also referred to as original waveform data. Reference waveform data in the first process). In this process, the absolute value of the difference from the received light amount data at all positions in the first waveform data) is obtained. In the example of FIG. 8, the received light amount data of the original waveform data are arranged in order in the horizontal direction, the waveform data to be synthesized are arranged in order in the vertical direction, the value of the light receiving position of the original waveform data is i, and i = 1. In the case of the first row from the left, the case of i = 2 is shown in the second row from the left. Further, the value of the light receiving position of the waveform data to be synthesized is j, the case where j = 1 is shown in the first row from the bottom, the case where j = 2 is shown in the second row from the bottom, and the like. The absolute value of the difference between the amount of light received at the th light receiving position and the amount of light received at the j th light receiving position of the waveform data to be synthesized is described in each cell as d (i, j). 8 and 9 exemplify the case where there are 14 light receiving positions, this is merely an example, and the number of light receiving positions of each waveform data obtained by the interpolation processing of S3 is arranged. Will be.

  For example, since the received light amount at the first light receiving position of the original waveform data is “0” and the received light amount at the first light received position of the waveform data to be synthesized is “0”, d (1, 1) is It becomes “0”. Therefore, “0” is recorded in the cell of i = 1 and j = 1 in FIG. Similarly, the amount of light received at the second light receiving position of the original waveform data is “55”, and the amount of light received at the first light receiving position of the waveform data to be synthesized is “0”, so d (2, 1) Becomes “55”, the light reception amount at the third light reception position of the original waveform data is “80”, and the light reception amount at the first light reception position of the waveform data to be synthesized is “0”. , 1) becomes “80”. In this way, as shown in FIG. 8, the absolute value of the difference between the received light amount data of all the light receiving positions of the original waveform data and the received light amount data of all the received light positions of the waveform data to be synthesized is obtained.

  Further, all the light receiving positions of the original waveform data are associated with all the light receiving positions of the waveform data to be synthesized, and an accumulated value at each corresponding position is obtained. FIG. 9A shows correspondence between each light receiving position of the original waveform data and each light receiving position of the waveform data to be synthesized, and the accumulated value at each corresponding position. The accumulated value for the corresponding position in which the light receiving position is associated with the jth light receiving position of the waveform data to be combined is shown as g (i, j). The accumulated value g (i, j) of the corresponding position is calculated by the equation (1).

  In Equation 1, the minimum value among the upper, middle, and lower expressions in the right parenthesis is the accumulated value g (i, j). D (i, j) represents the absolute value of the difference between the received light amount at the i th light receiving position of the original waveform data and the received light amount at the j th light received position of the waveform data to be synthesized, It is obtained by the above calculation (see FIG. 8). FIG. 9A shows the accumulated value (i, j) at each corresponding position. Regarding the light receiving position of the original waveform data, the case where i = 1 is the first column from the left, and the case where i = 2 is shown. It is shown in the second row from the left. For the waveform data to be synthesized, the case where j = 1 is shown in the first column from the bottom, and the case where j = 2 is shown in the second column from the bottom.

  As described above, after obtaining the cumulative value g (i, j) for each corresponding position (i, j), the minimum cumulative path is obtained from the upper right to the lower left of the table of FIG. 9B. First, the upper right cell (i = 14, j = 14 cell in FIG. 9) is focused on as a start cell. Then, the cell having the smallest cumulative value is detected from the cells adjacent to the cell of interest (cells arranged on the top, bottom, left, and right of the cell of interest, or diagonally), and this cell is determined as a new cell of interest. Thereafter, similarly, the cell with the smallest accumulated value is detected from the top, bottom, left, and right of the new target cell, and this cell is determined as the new target cell. By sequentially determining the target cell in this way, a route as shown in FIG. 9B is obtained.

  Synthetic data is generated based on the minimum cumulative path obtained in this way. Specifically, based on the minimum accumulated path, a light receiving position (one or a plurality of positions) corresponding to each light receiving position of the original waveform data is detected from the waveform data to be synthesized. And the average value of the received light amount at these light receiving positions corresponding to each other (that is, the received light amount at each light receiving position of the original waveform data and one or more light receiving positions of the waveform data to be synthesized corresponding to each light receiving position) The average value of the received light amount) is calculated, and this average value is set as a new received light amount at each light receiving position of the original waveform data.

  For example, referring to the minimum cumulative path, the first light receiving position of the original waveform data corresponds to the first and second light receiving positions of the waveform data to be synthesized. Average value “20/3” obtained by averaging the received light amount “0”, the received light amount “0” at the first light receiving position and the received light amount “20” at the second light receiving position of the waveform data to be synthesized. Is calculated as a new light receiving amount at the first light receiving position of the original waveform data. Similarly, referring to the minimum cumulative path, the second light receiving position of the original waveform data corresponds to the third light receiving position of the waveform data to be synthesized. An average value “98/2” (ie, 49) obtained by averaging the received light amount “55” and the received light amount “43” at the third light receiving position of the waveform data to be synthesized is calculated, and this is calculated as the original waveform data. The new light receiving amount at the second light receiving position of. As described above, the original waveform data and the waveform data to be synthesized are synthesized with reference to the minimum accumulation path for all the light receiving positions of the original waveform data to generate new original waveform data.

  After the synthesizing process is performed and new original waveform data is generated, a process of determining whether or not there is waveform data to be synthesized remains in S44. In this embodiment, other waveform data is sequentially synthesized with the reference waveform data determined first, and when other waveform data to be synthesized remains, the process proceeds to Yes in S44, and again. Returning to S42, any remaining waveform data is selected as waveform data to be synthesized. And the process which synthesize | combines the waveform data with the new original waveform data produced | generated in the last S43 is performed (S43). On the other hand, if the synthesis of all other waveform data has been completed, the process proceeds to No in S44. The synthesized data (final waveform data finally obtained) obtained by synthesizing all the waveform data is gentle compared with the reference waveform data in FIG. 5A and the first waveform data in FIG. The shape is a shape that accurately reflects the bar width of the barcode B.

As shown in FIG. 2, after the process of S4, a decoding process is performed based on the combined waveform data generated in S4 (S5). Note that the point of performing the decoding process based on the waveform data is well known in the field of bar code readers, so the details are omitted.
In the present embodiment, the control circuit 40 and the program of FIG. 2 correspond to an example of “decoding means”.

  As described above, in the present embodiment, a plurality of waveform data including reflection level data (light reception amount data) at a plurality of positions in the bar arrangement direction of the barcode is generated, and the plurality of waveform data are synthesized while being aligned. A single composite waveform data reflecting the plurality of waveform data is generated. In this way, it is possible to obtain waveform data that reflects the barcode bar array with higher accuracy, and to perform good decoding processing based on such waveform data.

  In the light receiving sensor 28, a plurality of element arrays are arranged in a direction orthogonal to the column direction (predetermined direction) of the element arrays, and a plurality of waveform data are generated based on light reception signals from the plurality of element arrays. Yes. In this way, a plurality of waveform data can be quickly generated, and since the waveform acquisition positions are different, it is possible to generate combined waveform data in which the influence of noise is reduced. In addition, since the light receiving element rows are arranged in a direction orthogonal to the row direction of the element rows, the waveform data can be aligned quickly and satisfactorily.

  In addition, when generating waveform data, interpolation data is generated based on reflection level data at a plurality of positions to compensate for intermediate positions that are shifted from the plurality of positions (reflection level data acquisition positions). The waveform data is composed of the intermediate position interpolation data. If the composite waveform data is generated after composing the waveform data obtained by interpolating the intermediate position with the interpolation data in this way, it is possible to perform the synthesis with appropriate consideration of the intermediate position other than the reflection level data acquisition position. The combined waveform data reflecting the barcode with higher accuracy can be generated.

  Further, any one of a plurality of waveform data is used as reference waveform data, and the other waveform data is aligned and synthesized for each reflection level data with respect to the reference waveform data. In this way, the synthesis process can be performed quickly and suitably.

[Second Embodiment]
Next, a second embodiment will be described. FIG. 11 is a flowchart illustrating the waveform data synthesis process in the second embodiment. In the present embodiment, only a part of the waveform data synthesis process is different from that of the first embodiment, and the other parts are the same as those of the first embodiment. Therefore, detailed description of the same parts is omitted. .

  The waveform data synthesis process shown in FIG. 11 is the same as S41 to S43 in FIG. 3 with respect to S141 to S143. After the synthesizing process similar to S43 is performed in S143, it is determined in S144 whether the final cumulative value is equal to or greater than the threshold value. The final cumulative value is the cumulative value at the end (upper right corner) of the minimum cumulative path shown in FIG. 9B, and is “525” in FIG. 9B. This final cumulative value is a value that is small when the similarity between the original waveform data and the waveform data to be synthesized is high, and increases when the similarity is low, and the final cumulative value exceeds a predetermined threshold value In step S144, the process proceeds to No, and the waveform data to be synthesized in the immediately preceding S143 (that is, the waveform data to be synthesized selected in the immediately preceding S142) is excluded from synthesis targets. That is, in this case, the original waveform data before the synthesis process is performed in S143 is set as new original waveform data again. On the other hand, if the final cumulative value is greater than or equal to a predetermined threshold, the process proceeds to No in S144. In this case, similarly to the first embodiment, the waveform data after the synthesis processing in S143 becomes new original waveform data.

As described above, in the present embodiment, whether or not the waveform data to be synthesized is in a predetermined similar state to any one or a plurality of other waveform data (specifically, a predetermined similar state to the original waveform data) Whether or not the final accumulated value exceeds the threshold value, and the waveform data determined not to be in a predetermined similar state is excluded from the synthesis targets. In this way, dissimilar waveform data that should not be synthesized (for example, waveform data that is dissimilar due to contamination or the like) can be removed.
The control circuit 40 corresponds to an example of “similarity determination means”.

[Other Embodiments]
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  In the above embodiment, the area sensor is used as the light receiving sensor, but the light receiving sensor may be configured by a line sensor. In this case, a plurality of image data for the barcode may be generated by performing light reception processing a plurality of times by the line sensor, and a plurality of waveform data may be generated based on the image data.

  In the said embodiment, the method like 1st Embodiment was illustrated as a method of combining the produced | generated several waveform data, aligning and producing | generating the single synthetic | combination waveform data reflecting several waveform data. However, another method may be used. For example, for all waveform data after the interpolation processing in S3, an average value may be obtained for each light receiving position, and a set of these average values for each light receiving position may be used as combined waveform data.

  In the above-described embodiment, an example is shown in which it is determined whether or not the waveform data to be synthesized is “a predetermined similar state” with any one or more other waveform data (specifically, the original waveform data). However, it is not limited to this. For example, instead of the process of S144 in FIG. 11, another method for determining the similar state may be used. Specifically, in the determination process of S144 in FIG. 11, for each light receiving position, an absolute value of a difference between the received light amount of the original waveform data and the received light amount of the waveform data to be synthesized is obtained, and the absolute value of this difference is calculated. A case where the sum is less than a predetermined threshold value may be set as a “predetermined similar state”. For example, the absolute value Z1 of the difference between the amount of light received at the first light receiving position of the original waveform data and the amount of light received at the first light receiving position of the waveform data to be synthesized is obtained, and similarly the second value of the original waveform data is obtained. The absolute value Z2 of the difference between the received light amount at the light receiving position and the received light amount at the second light receiving position of the waveform data to be synthesized is obtained, and the absolute difference at the last nth light receiving position is thus obtained. Find up to the value Zn. Then, these sums, that is, Z1 + Z2 +... + Zn may be obtained, and it may be determined whether or not the sum is equal to or greater than a predetermined threshold in the process of S144. If the sum is larger than a predetermined threshold value, the difference in the amount of light received at each light receiving position is comprehensively large and it can be determined that the similarity is low. In such a case, Yes in S144. Then, the waveform data to be synthesized is excluded from the synthesis targets in the same manner as in the above-described processing of S145 (that is, the original waveform data before the synthesis processing of the latest S143 is used as new original waveform data). On the other hand, if the sum is less than the threshold value, the process proceeds to No in S144, and the original waveform data after the synthesis processing of the latest S143 is used as new original waveform data.

FIG. 1 is a block diagram schematically illustrating an electrical configuration of a barcode reader according to the first embodiment of the present invention. FIG. 2 is a flowchart illustrating the flow of the reading process. FIG. 3 is a flowchart illustrating the flow of waveform data synthesis processing. FIG. 4A is an explanatory diagram for explaining the relationship between the element configuration of the light receiving sensor 28 and the barcode image formed on the light receiving sensor 28, and FIG. 4B is a diagram of FIG. 4A. It is explanatory drawing which shows the image data obtained based on a barcode image. FIG. 5A is a graph showing an example of the waveform data, and FIG. 5B shows the waveform data after regeneration after the interpolation processing is performed on the waveform data of FIG. It is a graph. 6A is an enlarged view of a part of the waveform data in FIG. 5A, and FIG. 6B is an interpolation process performed on the waveform data in FIG. 6A. The example which reproduced | regenerated the waveform data containing data is shown. FIG. 7A is a graph illustrating other waveform data to be synthesized with the original waveform data, and FIG. 7B shows the waveform data of FIG. 5A and the waveform data of FIG. It is the graph which aligned and superimposed. FIG. 8 is a table showing the absolute value of the difference between the received light amount at each light receiving position of the original waveform data and the received light amount at each light receiving position of the waveform data to be synthesized. FIG. 9A is a table in which each light receiving position of the original waveform data is associated with each light receiving position of the waveform data to be synthesized, and shows a cumulative value at each corresponding position. FIG. 10 shows a minimum cumulative path based on the cumulative value of FIG. FIG. 10 is a graph illustrating synthesized waveform data obtained by synthesizing all waveform data. FIG. 11 is a flowchart illustrating the waveform data synthesis process in the second embodiment.

Explanation of symbols

1 Bar code reader (optical information reader)
27 ... Imaging lens 28 ... Light receiving sensor (area sensor)
40. Control circuit (generating means, waveform synthesizing means, decoding means, similarity determining means)
B ... Barcode

Claims (5)

A light receiving sensor including an element row in which a plurality of light receiving elements are arranged in a predetermined direction;
An imaging lens that forms an image of reflected light from the barcode with the light receiving sensor;
Generating means for generating a plurality of waveform data including reflection level data at a plurality of positions in the bar arrangement direction of the bar code based on the respective light receiving signals from the plurality of light receiving elements constituting the element row;
A plurality of the waveform data generated by the generating means, and synthesizing while aligning, and a waveform synthesis means for generating a single synthesized waveform data reflecting the plurality of waveform data;
Decoding means for performing decoding processing based on the synthesized waveform data generated by the waveform synthesis means;
An optical information reading apparatus comprising: The light receiving sensor is an area sensor in which a plurality of the element rows are arranged in a direction orthogonal to the predetermined direction,
The optical information reader according to claim 1, wherein the generation unit generates a plurality of the waveform data based on the light reception signals from the plurality of element rows in the area sensor. The generation means generates interpolation data that compensates for an intermediate position shifted from the plurality of positions based on the reflection level data at the plurality of positions, and also generates the reflection level data at the plurality of positions and the interpolation data at the intermediate positions. And constitutes the waveform data,
3. The optical information reading apparatus according to claim 1, wherein the waveform synthesizing unit generates the synthesized waveform data by synthesizing a plurality of the waveform data including the interpolation data.   The waveform synthesizing means uses any one of the plurality of waveform data as reference waveform data, and synthesizes the reference waveform data by aligning each other waveform data for each reflection level data. The optical information reader according to any one of claims 1 to 3. Similarity determination means for determining whether the waveform data is in a predetermined similar state with any one or a plurality of other waveform data,
The said waveform synthetic | combination means excludes the said waveform data determined not to be the said predetermined | prescribed similar state by the said similarity determination means from the synthetic | combination object, The Claim 1 characterized by the above-mentioned. Optical information reader.

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