JP2023111459A - Information reader - Google Patents

Abstract

To reduce the influence of an environment where a device is installed or changes with time, regarding accuracy of recognizing a magnetic ink character, and allow the magnetic ink character to be read with high accuracy regardless of sudden change of speed during sheet conveyance.SOLUTION: An information reader includes: conveyance means for conveying a sheet with a magnetic ink character printed thereon along a conveyance path; conveyance speed detection means for detecting a conveyance speed of the sheet conveyed by the conveyance means; magnetic data detection means of detecting magnetic data of the magnetic ink character printed on the sheet conveyed on the conveyance path, and outputting a detected signal waveform; magnetic data correction means of correcting the detected signal waveform output from the magnetic data detection means on the basis of the conveyance speed detected by the conveyance speed detection means; and magnetic ink character recognition means of recognizing the magnetic ink character printed on the sheet from the detected signal waveform corrected by the magnetic data correction means.SELECTED DRAWING: Figure 6

Description

The present invention relates to an information reader having means for recognizing magnetic ink characters printed on sheets such as checks and bills.

Payments at stores and transactions at banks are sometimes settled using checks or the like. In settlement processing by check, the magnetic ink characters such as the financial institution number, branch number, account number, amount, etc. printed in the lower column of the check are read, and the read data is referred to the designated institution to confirm the validity of the check. do. Therefore, the accuracy of reading magnetic ink characters is very important in the check settlement process.

As a device for reading magnetic ink characters, an information reading device equipped with a magnetic ink character recognition (hereinafter sometimes referred to as MICR) processing unit is known. The magnetic ink character recognition processor reads magnetic data contained in the magnetic ink characters, outputs them as detection signal waveforms, and recognizes the characters based on the output detection signal waveforms.

There are individual differences in the transport system of such an information reading device. For example, the roundness of the conveying roller, the amount of movement of the sheet per rotation of the conveying motor, the coefficient of friction with the sheet, and the like differ depending on the individual apparatuses. As a result, the detection signal waveform deviates in the direction of the time axis due to variations in sheet conveying speed, and the magnetic ink characters printed on the sheet cannot be correctly recognized.

On the other hand, in Patent Document 1, a standard reference information reader is prepared. It is described that a correction value is calculated by comparing a detected signal waveform when reading a reference sheet. This correction value is stored in the target information reading device, the detection signal waveform when actually reading the sheet is corrected with the stored correction value, and character recognition is performed based on the corrected detection signal waveform. By doing so, reading accuracy is improved. Further, Japanese Patent Application Laid-Open No. 2002-200000 describes that it is preferable to read the reference sheet a plurality of times by the target information reading device in order to obtain a more appropriate correction value.

JP 2010-26644 A

However, since the information reading apparatus described in Japanese Patent Application Laid-Open No. 2002-200002 corrects the detection signal waveform based on the correction value stored in advance, the speed fluctuation that occurs suddenly during the sheet conveying operation can be prevented. cannot respond. In addition, the sheet conveying speed is affected by the installation environment such as temperature and humidity, and changes in the apparatus over time, but this influence cannot be eliminated. Furthermore, as described above, in the apparatus disclosed in Patent Document 1, it is necessary to read the reference sheet multiple times during the production process in order to obtain a more appropriate correction value, which reduces production efficiency and is therefore impractical.

In view of the above problems, an information reading apparatus of the present invention includes a conveying means for conveying a sheet on which magnetic ink characters are printed along a conveying path, and a conveying speed detector for detecting the conveying speed of the sheet conveyed by the conveying means. means, magnetic data detecting means for detecting magnetic data of magnetic ink characters printed on the sheet conveyed on the conveying path and outputting a detection signal waveform, and detection signal waveform output from the magnetic data detecting means. based on the conveying speed detected by the conveying speed detecting means; and a magnetic data correcting means for recognizing magnetic ink characters printed on the sheet from the detected signal waveform corrected by the magnetic data correcting means. and ink character recognition means.

According to the present invention, it is possible to reduce the influence of the installation environment of the device and the aging change on the recognition accuracy of the magnetic ink characters, and to read the magnetic ink characters with high accuracy without being affected by sudden speed fluctuations during sheet conveyance. Become.

1 is a schematic perspective view showing an example of a usage pattern of an information reading device according to an embodiment of the present invention; FIG. 1 is a schematic plan view showing the configuration of a check, which is an example of a sheet on which magnetic ink characters are printed; FIG. Schematic diagram showing an example of the shape of a magnetic ink character. Schematic diagram showing an example of a shape of a magnetic ink character and a signal waveform detected from the character. 1 is a schematic cross-sectional view showing the internal configuration of an information reader according to one embodiment of the present invention; FIG. 1 is a block diagram showing a control system of an information reader according to one embodiment of the present invention; FIG. The figure which shows an example of the dictionary data in one Embodiment of this invention. 4 is a flowchart for explaining MICR processing in one embodiment of the present invention; The figure which shows an example of the sample table in one embodiment of this invention. The figure which shows an example of the detection signal waveform detected in one Embodiment of this invention. 4 is a flowchart for explaining a method of detecting variations in conveying speed according to an embodiment of the present invention; 4 is a flowchart for explaining a magnetic data correction method according to an embodiment of the present invention; FIG. 4 is a diagram showing an example of correction of a detection signal waveform in one embodiment of the present invention; 4 is a flowchart for explaining an OCR correction method according to one embodiment of the present invention; FIG. 4 is a diagram for explaining correction of a template in one embodiment of the present invention; 4 is a flowchart for explaining switching of transport control in one embodiment of the present invention; FIG. 2 is a diagram for explaining the configuration of a tracking sensor used in one embodiment of the present invention; Schematic diagram illustrating signal processing for an image obtained from a tracking sensor. Schematic diagram for explaining a speed detection method using a tracking sensor. FIG. 4 is a diagram for explaining a speed detection method when an encoder is used as a speed detection sensor; Schematic diagram for explaining the configuration of an encoder used to detect a conveying speed. Schematic diagram for explaining the arrangement of speed detection sensors.

Embodiments of the present invention will be described in detail below with reference to the drawings. The present invention is not limited to the following embodiments, and various modifications and applications are possible. The present invention includes all such modifications and applications without departing from the scope of claims.

FIG. 1 is a schematic perspective view showing an example of usage of the information reading apparatus of this embodiment. In FIG. 1, an information reader 300 of this embodiment is connected to a host device 301 via a communication cable 302 . The host device 301 is composed of, for example, a personal computer (PC), and includes an application for controlling reading of the information reading device 300, a scanner device driver, and the like. A bundle of sheets on which magnetic ink characters are printed is stacked on the sheet stacking table 100 . This sheet bundle is conveyed one by one through the conveying path 110 by conveying means (not shown) and discharged to the first and second discharge pockets 102 and 103 . Magnetic data detection means and optical reading means (not shown) are provided in the middle of the conveying path 110 , and character information recognized based on the data detected by these means is sent to the host device 301 via the communication cable 302 . transferred.

FIG. 2 is a schematic plan view showing the configuration of a check, which is an example of a sheet on which magnetic ink characters are printed. As shown in FIG. 2, a standardized string of magnetic ink characters is printed on a predetermined area 91 of the sheet 90 . The area 91 includes, from the left side of FIG. , and the amount column, and each column is printed with magnetic ink characters. Description will be made on the assumption that the magnetic ink characters are read from the right side to the left side, contrary to the order of the character strings. In an area 91 of a sheet (check) 90, not only normalized numerical values but also symbols are printed. In addition, the information printed on the sheet (check) 90 varies depending on the bank, branch office, etc., and the printed information is not limited to this.

FIG. 3 shows an example of the shape of magnetic ink characters. In FIG. 3, the height direction of characters is the X direction, and the width direction of the characters perpendicular to the X direction is the Y direction. FIG. 3(a) shows all 14 magnetic ink characters in the E13B font. Here, the character size and character spacing are defined by standards. FIG. 3B shows a template of a magnetic ink character "1" as an example of a template of image data of each character held in an Optical Character Recognition (OCR) dictionary table storage unit 23, which will be described later. A magnified view is shown.

FIG. 4 is a schematic diagram showing an example of a detection signal waveform output when a magnetic ink character is detected by a magnetic data detection means, which will be described later. The upper half of FIG. 4 shows the shape of the magnetic ink character "8" as an example of the character shape, and the lower half shows the detection signal waveform (output waveform) when this character "8" is detected. In the diagram of the output waveform, the vertical axis indicates the signal amplitude and the horizontal axis indicates the time axis. Before and after the detection position, peaks p1 to p6 are detected in the detection signal at the timing when the magnetism changes from the state where the magnetism does not change.

Magnetic ink character recognition recognizes characters based on the peak position on the time axis of the detection signal waveform shown in FIG. On the other hand, these peak positions change depending on the conveying speed of the sheet on which the magnetic ink characters are printed. If there is no trouble during conveyance and the sheet is conveyed at a stable speed, a predetermined detection signal waveform is output. changes. As will be described later, this embodiment detects the conveying speed, corrects the detected signal waveform based on the detected conveying speed, and recognizes magnetic ink characters from the corrected detected signal waveform.

FIG. 5 is a schematic cross-sectional view showing the internal configuration of the information reader of this embodiment. 5, the same members as in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. A plurality of sheets 90 shown in FIG. 2 are set on the sheet stacking table 100 of the information reading device 300 . The sheets 90 are conveyed one by one through the conveying path 110 and discharged to either the first or second discharge pocket 102 or 103 . More specifically, the information reader 300 operates as follows.

A bundle of sheets 90 stacked on the sheet stacking table 100 is pressed against a paper feed roller 104 by a pressing plate (pressing member) 101 . The pressing plate 101 is rotatably provided on the apparatus main body, and is urged toward the sheet feeding roller 104 by a spring 111 . The sheet 90 pressed against the paper feed roller 104 is fed between the paper feed roller 105 and the separation roller 107 as the paper feed roller 104 rotates. 110. Here, even if the sheets 90 are fed in a bundle, they are separated one by one by the action of the separation roller 107 . An arrow D indicates the conveying direction of the sheet 90 .

The sheet 90 fed to the conveying path 110 is conveyed through the conveying path by a first conveying roller pair consisting of conveying rollers 201a and 201b and a second conveying roller pair consisting of conveying rollers 202a and 202b. Along the sheet conveying direction D, the first conveying roller pair is arranged on the upstream side, and the second conveying roller pair is arranged on the downstream side. These conveying roller pairs convey the sheet 90 at a constant speed by rotating at the same rotational speed.

The conveying speed of the sheet 90 conveyed along the conveying path 110 is detected by a speed detection sensor 109 arranged facing the conveying path 110 . A magnetic data detection unit 106 including a magnetic head sensor or the like is arranged facing the transport path 110 . The magnetic data detection unit 106 detects magnetic data of magnetic ink characters printed on the conveyed sheet 90 and outputs a detection signal waveform. A roller 207 that presses the sheet 90 against the magnetic data detection unit 106 is provided at a position facing the magnetic data detection unit 106 with the transport path 110 interposed therebetween.

Since the sheet 90 is conveyed at a constant speed between the first and second conveying roller pairs, the state of the sheet can be easily detected, and information can be obtained on the upstream side as much as possible and fed back to the conveying control. , various sensors are densely arranged. In this embodiment, a registration sensor (sheet detection means) 112 for detecting the sheets 90 and a multi-feeding detection sensor 113 for detecting that the sheets 90 are multi-fed and conveyed are arranged.

The sheet 90 that has passed through the second conveying roller pair is further conveyed downstream by several conveying rollers provided downstream from the second conveying roller pair. Then, the magnetic ink characters printed on the sheet 90 are optically read by the image reading sensor 108 . Sheets 90 that have passed through the image reading sensor 108 are sorted by a switching flapper 127 according to conditions described later, and discharged to the first discharge pocket 102 or the second discharge pocket 103 .

FIG. 6 is a block diagram showing the control system of the information reader of this embodiment. 6, the same members as in FIG. 5 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 6, the information reading device 300 includes a CPU (Central Processing Unit) 31 . The CPU 31 is connected via the data/address bus 33 to a magnetic ink character recognition (MICR) control section 505 , a conveying speed detection section 501 and an optical character recognition (OCR) recognition section 504 . Furthermore, the CPU 31 is connected to the sheet feeding control section 502 , the feeding control section 503 , the transport control section 506 , the memory 34 and the display section 35 . Further, the information reading device 300 is configured to be able to communicate with an external host device 301 via the external interface 32 .

The MICR control unit 505 has the magnetic data detection unit 106 described with reference to FIG. The magnetic data (detection signal waveform) detected by the magnetic data detection unit 106 undergoes processing such as amplification, A/D conversion, and smoothing of the electric signal in the magnetic data processing unit 11, and then subjected to magnetic data correction processing. Output to the unit 18 . The magnetic data correction processor 18 corrects the magnetic data (detection signal waveform) based on the conveying speed detected by the conveying speed detector 501 . The corrected magnetic data (detection signal waveform) is sent to the MICR processing section 13 . The MICR processing unit 13 refers to the MICR dictionary table stored in the MICR dictionary table storage unit 12, analyzes the detected signal waveform, and performs MICR processing. Character information recognized by the MICR processor 13 is sent to the CPU 31 via the data/address bus 33 .

A conveying speed detection unit 501 has the speed detecting sensor 109 described with reference to FIG. 5 and detects the speed of the sheet conveyed on the conveying path 110 . The output signal of the speed detection sensor 109 is processed by the speed detection processor 51 , and detection information of the detected conveying speed is sent to the magnetic data correction unit 18 of the MICR control unit 505 . Then, as described above, the magnetic data (detection signal waveform) is corrected based on this conveying speed detection information. Further, information about the conveying speed detection is sent to the CPU 31 via the OCR control section 504 and the data/address bus 33 . Further, the detection information of the conveying speed is also sent to the conveying control unit 506 and used for sheet conveying control.

The OCR control unit 504 has the image reading sensor 108 described with reference to FIG. 5, and optically reads magnetic ink characters printed on the sheet conveyed on the conveying path 110 . An output signal of the image reading sensor 108 is subjected to various processes in the image data processing section 21 and input to the OCR processing section 22 . The OCR processing unit 22 recognizes magnetic ink characters from image data based on templates stored in the OCR dictionary table storage unit 23 . Further, the conveying speed detection information is input from the conveying speed detecting unit 501 to the OCR processing unit 22 . Then, as will be described later, when there is a change in the transport speed that exceeds the first threshold with respect to the reference value, when the OCR processing unit 22 performs OCR processing, the above-mentioned Correct the mesh spacing of the template.

A paper feed control unit 502 controls the driving system of the paper feed roller 104 shown in FIG. The feeding control unit 503 controls the driving system of the feeding roller 105 and the separation roller 107 shown in FIG. 5 according to instructions from the CPU 31 . The conveying control unit 506 controls the first and second conveying roller pairs according to instructions from the CPU 31 to convey the sheet at a constant speed. In addition, according to instructions from the CPU 31, the conveying control unit 506 controls several conveying rollers provided downstream of the second conveying roller pair shown in FIG. The paper is transported to the paper pocket 102 or the second paper discharge pocket 103 (see FIG. 5). In this embodiment, these controllers, the rollers shown in FIG. 5, and their drive systems constitute the conveying means.

The display unit 35 is mounted with a power ON/OFF switch, an LED for displaying the status of the device, and the like, and serves as an interface (I/F) unit when the (user) operates the information reading device. there is In addition, when an error occurs during transportation or reading of magnetic information according to instructions from the CPU 31, the LED flashes as an error message (warning), for example, to inform the operator (user). Further, the notification unit 508 is means for warning the operator (user) using sound or light such as an LED when there is an error during transportation or reading of magnetic information according to instructions from the CPU 31 .

The CPU 31 controls each control unit as described above, and comprehensively controls the operation of the information reading device 300 . The CPU 31 also transmits character information recognized from magnetic data by the MICR control unit 505 and character information optically recognized by the OCR control unit 504 to the host device 301 via the external interface 32 . Character recognition in this embodiment will be specifically described below.

<MICR processing>
As described above, the MICR processing unit 13 converts the magnetic data (detection signal waveform) output from the magnetic data correction processing unit 18 shown in FIG. is referred to perform MICR processing. The MICR dictionary table storage unit 12 stores a MICR dictionary table for reference data for all characters of the E13B font. Here, the reference data is dictionary data having two elements of "peak position time" and "amplitude level". FIG. 7 shows an example of such dictionary data. Although FIG. 7 stores a dictionary table for one character, dictionary tables are created for all MICR characters (14 types). Although this table contains polarity data, the polarity is not used in this embodiment. Although the dictionary data shown in FIG. 7 is created with the number of peaks set to 4, the number of peaks is not limited to this. It is possible.

FIG. 8 is a flowchart for explaining MICR processing in this embodiment. In the following description, the reference numerals shown in FIG. 6 are used for the reference numerals attached to each member, and detailed explanations thereof are omitted. In step S301 of FIG. 8, the CPU 31 controls the MICR processing section 13 to extract magnetic character positions from the magnetic data (detection signal waveform) output from the magnetic data processing section 11. FIG. Character position segmentation is determined by detecting the character start position. To detect the character start position, first, the peak of the sampling waveform is detected from the magnetic data. Next, the character start position is obtained based on the first detected peak position, and a predetermined range is cut out as data for one character.

Next, in step S302, the CPU 31 controls the MICR processing unit 13 to reset the character number count N to 0, and proceeds to step S303. In step S303, the CPU 31 controls the MICR processing unit 13 to acquire the magnetic data of the N-th character, and proceeds to step S304. Here, the MICR processing unit 13 refers to the position information data stored in the memory 34 and cuts out the waveform of the portion corresponding to the position information data in the magnetic data. In step S304, the CPU 31 controls the MICR processing unit 13 to detect the peak position signal and create peak position data for the magnetic data of the N-th character, and proceeds to step S305.

The E13B font, which is the font for the magnetic ink characters in this embodiment, divides the width of one character into eight equal parts along the time axis, and the reading signal obtained when the characters are read by the magnetic data detection unit 106 is The peaks are arranged to reside in different blocks. Therefore, the MICR processing unit 13 divides each character into 8 equal parts, detects the peak position of the magnetic signal, and calculates the detected peak position as a peak position signal. Further, the MICR processing unit 13 detects the amplitude level for each peak position and calculates peak value data indicating the time and amplitude level at the peak position.

As a peak position detection method, for example, there is a method of detecting the point at which the amplitude level of the sampling waveform changes from increasing to decreasing and the point at which the amplitude level of the sampling waveform changes from decreasing to increasing as the peak position. In step S305, the CPU 31 controls the MICR processing unit 13 to create a sample table representing the relationship between the time of the peak position and the amplitude level (polarity) based on the peak value data obtained in step S304. , the process proceeds to step S306.

FIG. 9 shows an example of the sample table in this embodiment. In FIG. 9, for the sake of convenience, it is assumed that four peak positions of the magnetic data of the N-th character are detected, but the present invention is not limited to this. Next, in step S306, the CPU 31 controls the MICR processing unit 13 to compare the dictionary data of the MICR dictionary table shown in FIG. 7 with the data of the sample table created in step S305. The comparison processing here is performed by calculating the two-dimensional distances between the character peaks in the sample table and all the MICR dictionary tables.

FIG. 10 shows an example of detection signal waveforms detected from magnetic ink characters in this embodiment. As shown in FIG. 10, the distance L0 is the distance from the first peak S_peak0 of the sample table waveform to the first peak D_peak0 of the MICR dictionary table waveform. The distance L1 is the distance from the first peak S_peak0 of the sample table waveform to the second peak D_peak1 of the MICR dictionary table waveform. Distance L2 is the distance from the first peak S_peak0 of the sample table waveform to the third peak D_peak2 of the MICR dictionary table waveform. Distance L3 is the distance from the first peak S_peak0 of the sample table waveform to the fourth peak D_peak3 of the MICR dictionary table waveform.

These distances L0 to L3 are calculated by the following equations.
L0=√{A×(St_0−Dt_0) ² +B×(Sl_0−Dl_0) ² }
L1=√{A×(St_0−Dt_1) ² +B×(Sl_0−Dl_1) ² }
L2=√{A×(St_0−Dt_2) ² +B×(Sl_0−Dl_2) ² }
L3=√{A×(St_0−Dt_3) ² +B×(Sl_0−Dl_3) ² }
where A and B are predetermined constants. It should be noted that it is preferable to adjust the waveform data appropriately so that the aspect ratio of the waveform data does not become excessively long or wide when the distance is obtained by the above equation.

Next, based on the calculated distance, the MICR processing unit 13 round-robin determines which of the four terms in the MICR dictionary table the first term in the sample table is closest to. Memorize the distance of the peak. The entry in the dictionary table determined to be closest to the first sample data is omitted thereafter. Then, for the second item (St_1, Sl_1), the third item (St_2, Sl_2), etc. of the sample table, the two-dimensional distances of the terms of the MICR dictionary table are calculated in the same manner. Determine if it is close to Then, determine the distance between the closest peaks up to the fourth term (St_3, Sl_3) by round-robin, add the distance to the term determined as the closest to each sample data, and sum the total value is stored in the memory 34 shown in FIG.

Similarly, the sum of the distances judged to be the closest to the sample table of FIG. After completing the comparison with the dictionary table in step S306, the process proceeds to step S307 in FIG. In step S307, the CPU 31 controls the MICR processing unit 13 to determine the recognition result character from the sum of the distances calculated in step S306. Here, the CPU 31 selects, as the recognition result character, the character of the dictionary table whose total sum of distances calculated in step S306 is the smallest, as the character with the high degree of magnetic similarity.

In the MICR processing in this embodiment, the processing method is changed according to the variation rate of the sheet conveying speed detected by the conveying speed detection unit 501 with respect to the reference value. FIG. 11 is a flow chart for explaining a method for detecting variations in sheet conveying speed. At step S1301, sheet conveyance is started, and at the same time, a counter generated inside the CPU 31 is started at step S1302. The counter counts up when an interrupt is processed at an arbitrary fixed time. Usually, the resolution to detect the speed is calculated from the character spacing of the magnetic ink characters printed on the sheet and the conveying speed of the sheet, and the interrupt time suitable for it is set. In step S1303, it is determined from the count result of the counter whether a certain arbitrary time has been reached. If it is determined that the time has not yet been reached, the counter value is counted up in step S1312, and the cycle of step S1303 waits for an arbitrary time to elapse.

In step S1303, when n becomes an arbitrary value and a certain arbitrary time is reached, the process proceeds to step S1304. In step S1304, the movement amount of the sheet is read by the speed detection sensor 109, and the conveying speed is detected in step S1305 from the read movement amount and the time set by the counter. Then, in step S1306, it is determined whether or not the detected variation rate of the conveying speed with respect to the reference value exceeds the first threshold value. If it is determined that the rate of change has exceeded the first threshold, that is, if the determination in step S1306 is YES, the process proceeds to step S1307. Then, in step D1307, the speed variation rate is calculated, in step S1308, the speed-varying position is specified, and in step S1309, this speed variation rate and the speed-varying position are stored in the memory . Then, the process advances to step S1310 to reset the counter value.

On the other hand, if it is determined in step S1306 that the speed fluctuation does not exceed the first threshold value (is equal to or less than the first threshold value), that is, if the determination in step S1306 is NO, the process proceeds to step S1310, and the counter Reset value. Then, in step S1311, it is determined whether or not the sheet has been conveyed, and this operation is repeated until the sheet is conveyed. Then, a record is kept of how much speed fluctuation occurred at which position on the sheet. Here, the end of sheet conveyance can be determined based on information such as the registration sensor 112 (see FIG. 5) arranged on the conveyance path 110 .

Next, a method of correcting magnetic data (detection signal waveform) when there is a speed variation exceeding the first threshold will be described with reference to the flow chart of FIG. In the following description, the reference numerals shown in FIGS. 5 and 6 are used for the reference numerals attached to each member, and detailed explanations thereof are omitted. If it is determined in step S1801 in FIG. 12 that the variation rate of the conveying speed exceeds the first threshold, the process advances to step S1802. In step S1802, it is determined at which position on the sheet the speed has fluctuated, and the process proceeds to step S1803. The speed fluctuation information detected by the speed detection sensor 109 is acquired at regular intervals by the interrupt processing of the CPU 31. Therefore, if information such as the registration sensor 112 (see FIG. 5) on the top of the sheet is known, the position can be specified. be.

If the correction characters are identified, a correction rate is determined based on the conveying speed detected by the speed detection sensor 109 in step S1803. Then, in step S1804, the magnetic data (magnetic characters) are corrected. If the actual conveying speed of the sheet is faster than the reference conveying speed of the sheet, the detection signal waveform (magnetic ink character waveform) is corrected to expand in the sheet conveying direction. Conversely, if it is slow, it is corrected in the direction of contraction with respect to the sheet conveying direction.

FIG. 13 is a diagram showing an example of correction of the detection signal waveform (magnetic ink character waveform) performed in step S1804. When the sheet conveying speed fluctuates from the reference conveying speed to a low speed, the peak positions of p3 to p4 in the middle part of the magnetic ink character "8" shown in (a) extend as shown in (b). I know there is. The movement amount per unit time is read by the speed detection processing unit 51, and the conveying speed is detected from the read movement amount and the unit time. Therefore, the amount of deviation from the reference conveying speed can be calculated. Then, the magnetic ink character waveform sampled by the MICR control unit 505 is corrected by multiplying the deviation amount by a correction multiplier to generate a corrected detection signal waveform (magnetic ink character waveform) as shown in FIG. 13(c). do.

When the correction of the magnetic data (magnetic characters) is completed in step S1804, the process advances to step S1805. On the other hand, if it is determined in step S1801 that the variation rate of the sheet conveying speed is equal to or less than the first threshold value, the peak positions p1 to p6 of the magnetic character waveform shown in FIG. Move to (MICR) processing.

In step S1805, magnetic ink characters are decoded based on the corrected sampling waveform. In the decoding process, the magnetic characters are recognized by the procedure described with reference to FIG. If the decoding process proceeds without correcting the output waveform, the sum of the distances calculated in step S306 of FIG. However, as in the present embodiment, by correcting the magnetic ink character waveform based on the detected speed variation, it is possible to greatly reduce the probability of unread characters. Next, in step S1806, it is determined whether character recognition has been completed. If character recognition is successful, that is, if the determination in step S1806 is YES, the result is output in step S1807, and the process ends. On the other hand, if the determination result in step S1806 indicates that the character cannot be recognized, unread processing is performed in step S1808, the result is output, and the processing ends.

<OCR processing>
Next, optical recognition (OCR) processing of magnetic ink characters in this embodiment will be described. As described with reference to FIG. 6, when the sheet conveying speed fluctuates from the reference value by exceeding the first threshold value, the OCR processing unit 22 performs OCR processing according to the conveying speed detection information. The mesh spacing of the template stored in the OCR dictionary table storage unit 23 is corrected.

As the dictionary data stored in the OCR dictionary table storage unit 23, a template of image data of each character is stored. FIG. 3(b) above shows an enlarged view of the template for the character "1". The OCR processing unit 22 performs optical character recognition (OCR) processing on the image data of the magnetic ink characters output from the image data processing unit 21 with reference to this template. Specifically, using the upper left corner of the obtained image data as the coordinate starting point, the image corresponding to the template width and height of the OCR dictionary table is compared with all the templates of the OCR dictionary table to count the non-coincidence rate pixels. After that, the comparison between the template and the OCR dictionary table is repeated by shifting one pixel each in the vertical and horizontal directions. Then, when there is a template with a mismatch rate count smaller than a predetermined number, the character is fixed and the recognition result is output.

FIG. 14 is a flowchart for explaining the OCR correction method for magnetic ink characters in this embodiment. In the following description, the reference numerals shown in FIGS. 5 and 6 are used for the reference numerals attached to each member, and detailed explanations thereof are omitted. If it is determined in step S801 in FIG. 14 that the variation rate of the sheet conveying speed is equal to or less than the first threshold value, the process advances to step S805 without changing the width of the template, and the OCR processing is performed as usual. On the other hand, if it is determined in step S801 that the rate of change in the conveying speed has exceeded the first threshold value, in step S802, it is determined at which position on the sheet the speed has changed. The speed fluctuation information detected by the speed detection sensor 109 is acquired at regular intervals by the interrupt processing of the CPU 31. Therefore, if information such as the registration sensor 112 (see FIG. 5) on the top of the sheet is known, the position can be specified. be.

If the correction character is identified in step S802, the correction rate of the template held in the OCR dictionary table storage unit 23 is determined in step S803 based on the conveying speed detected by the speed detection sensor 109. FIG. Then, in step S805, the template is changed. Here, when the sheet is conveyed faster than the reference conveying speed, the template interval is corrected to expand. do.

FIG. 15 is a diagram for explaining template correction in step S804. FIG. 15(a) is a diagram in which the character "1" read when the document is conveyed normally is applied to the template of the OCR dictionary table 23. FIG. On the other hand, FIG. 15B is a diagram in which the character "1" read during low-speed transport is applied to the template. Furthermore, FIG. 15(c) is a diagram in which the template interval is corrected in synchronization with the transport speed. For example, if the sheet conveying speed fluctuates lower than the reference conveying speed at the position of the magnetic ink character "1", the image of the magnetic ink character "1" will be stretched. Therefore, if the interval L1 in the template X-axis direction is used as the normal interval, the region in which the characters in the template are filled changes as shown in FIG. 15(b).

Optical character recognition (OCR) processing uses the upper left corner of the acquired image data as a coordinate starting point, compares the image for the template width and height of the OCR dictionary table with all the templates of the OCR dictionary table, and counts pixel mismatches. After that, the comparison between the template and the OCR dictionary table is repeated by shifting one pixel each in the vertical and horizontal directions. If there is a template with a mismatch rate count smaller than a predetermined number, that position is recognized as the character position. However, in the case of the characters in FIG. Otherwise, it will become unread.

As described above, since the position of the magnetic ink character whose velocity variation rate exceeds the first threshold and the velocity variation rate have been specified, in step S804 of FIG. to correct. The template is corrected with respect to the amount of deviation from the reference conveying speed, the template width L1 is corrected as shown in FIG. 15(c), and the process proceeds to step S805. In step S805, the OCR process performs character recognition according to the procedure described with reference to FIG. Next, in step S806, it is determined whether or not character recognition has been completed. If character recognition is successful in step S806, the result is output in step S807, and the process ends. On the other hand, if the character cannot be recognized in step S806, the process advances to step S808 to perform unread processing, and then in step S807 the result is output and the process ends.

In the present embodiment, the same first threshold as in the case of MICR processing is used as the threshold for the fluctuation rate of the transport speed in OCR processing, but these thresholds may be different. That is, if the threshold in OCR processing is the third threshold, the third threshold may be the same value as or different from the first threshold.

<Conveyance control when character recognition is not possible>
In this embodiment, when the rate of change in the transport speed is greater than the second threshold value and the characters cannot be recognized, transport control different from that in the normal case is performed. Here, the second threshold is set to a value greater than the first threshold. FIG. 16 is a flowchart illustrating switching of transport control in this embodiment. In the following description, the reference numerals shown in FIGS. 5 and 6 are used for the reference numerals attached to each member, and detailed explanations thereof are omitted.

If it is determined in step S2001 in FIG. 16 that the variation rate of the sheet conveying speed is equal to or less than the second threshold value, the process advances to step S2005, and the conveying control unit 506 controls the switching flapper 127 to switch to the normal sheet discharge pocket (second 1 discharge pocket 102). On the other hand, if it is determined that the variation rate of the sheet conveying speed is greater than the second threshold, the process advances to step S2002. In step S2002, it is determined whether the magnetic ink characters have been recognized, that is, whether they have been decoded by MICR processing. When it is determined that the magnetic ink characters have been decoded by the MICR process, the flow advances to step S2005 to eject the paper to a normal paper ejection pocket (first paper ejection pocket 102). On the other hand, if it is determined in step S2002 that the magnetic ink characters could not be decoded by MICR processing, the process advances to step S2003.

In step S2003, the transport control unit 506 controls the switching flapper 127 to switch the paper discharge pocket to the reject pocket (second paper discharge pocket 103) and discharge the paper. Thereafter, in step S2004, it is determined whether the error state (warning) should be notified to the operator (user) by the notification means 508. FIG. In step S2004, if notification is to be performed, the process advances to step S2006 to notify an error message. On the other hand, if it is determined not to notify in step S2004, the process ends. As for the notification method in step S2006, an error message may be displayed on the liquid crystal display or within an application running on the PC, or the lighting color or blinking interval of the LED may be changed for notification. Also, the first and second discharge pockets 102 and 103 may be changeable. In other words, which of the first and second paper ejection pockets 102 and 103 is to be the normal paper ejection pocket and which is to be the reject pocket can be arbitrarily set before the start of transportation.

<Configuration of speed detection sensor>
In this embodiment, any sensor may be used as the speed detection sensor 109 as long as it can detect the sheet conveying speed. As a contact-type sensor, for example, a roll-type encoder may be attached to the shaft of the conveying roller. In this case, the speed fluctuation can be detected from the cycle of the clock (CLK) signal output from the encoder as the conveying roller rotates. Another method is to detect the behavior of the sheet based on the signal output from the Hall element by using a circular magnet and a Hall element, and by configuring the magnet to rotate when the sheet is conveyed. .

As the non-contact sensor, a plurality of infrared sensors may be installed along the conveying path from upstream to downstream to detect movement of the leading edge of the sheet. However, this configuration may require a large layout area or increase the cost. Therefore, in this embodiment, a tracking sensor is used as the speed detection sensor 109 . The tracking sensor detects the conveying speed of the sheet by tracking changes in the sheet image obtained by optically imaging the sheet. A tracking sensor is used in a mouse or the like, and is preferable as a non-contact optical sensor because it can be constructed at a low cost. However, not only the tracking sensor but also two or more of the speed detection sensors described above can be used in combination. Also, a contact sensor and a non-contact optical sensor may be used together to improve the detection accuracy of the conveying speed.

FIG. 17 is a diagram for explaining the configuration of the tracking sensor used in this embodiment. As shown in FIG. 17A, the tracking sensor 311 is composed of a light emitting section 302, a light receiving section 311a including the imaging sensor 310, and a condenser lens 303. As shown in FIG. A substrate 400 on which a light receiving portion 311a is mounted is attached at a position facing the transport path 110 (see FIG. 5). Both the light-emitting part 302 and the light-receiving part 311a may be mounted on the substrate, or they may be mounted on separate substrates for layout reasons. Here, as the imaging sensor 310, an area image sensor is used. An infrared laser beam or an LED light source is used for the light emitting unit 302, and a surface image of the sheet is obtained by receiving reflected light that is reflected by the sheet or the like. In particular, it is preferable to use a laser method because it is possible to detect the movement amount of the sheet in more detail.

A tracking sensor is also called a tracking sensor. As shown in FIG. 17A, the sheet (original) being conveyed is irradiated with light from the light emitting unit 302 within one detection area. On the other hand, after the light reflected by the surface of the sheet (original) is collected by the lens 303, an image obtained by receiving the light by the imaging unit 311a is acquired at a predetermined sampling period. Then, the movement of the tracking target area included in the image is tracked, and based on the result, the movement amount or movement direction of the sheet (original) is detected.

FIG. 17(b) is a diagram for explaining the electrical block configuration of the tracking sensor. Inside the light receiving unit 311a shown in FIG. 17A, a TG (Timing Generator) 131 drives the imaging sensor 310 to acquire an image signal. Then, the A/D conversion and the image signal are analyzed to detect the conveying speed of the object to be imaged. A light source 302 , a driver 134 for the light source 302 , an imaging sensor 310 , a TG 131 , an AFE (Analog Front End) 132 and a DSP (Digital Signal Processor) 133 are provided inside the tracking sensor. When the DSP 133 instructs the TG 131 to start acquiring an image signal, the TG 131 outputs pulses necessary for the operation of each module. The light source 302 is turned on via the drive unit 134, and the imaging sensor 310 acquires an image of the imaging target. The AFE 132 performs A/D conversion on the image signal acquired, and the DSP 133 detects the amount of movement of the imaging object based on the digital image signal (so-called system-on-chip (SoC)). ).

As another embodiment, the tracking sensor 311 may only acquire image signals, and an image signal processing device (not shown) may be prepared as a separate device. In this case, the image signal processing device performs A/D conversion and image signal analysis to detect the amount of displacement or moving direction of the object to be imaged. In this embodiment, the displacement amount is determined by comparing sheet images captured at predetermined intervals (or images based on the predetermined displacement amount interval), and feature points are extracted. Based on the characteristic points, it is possible to detect the movement amount or movement direction of the sheet. Alternatively, the image acquired by the tracking sensor 311 may be transmitted to an external device and the displacement amount may be determined on the external device. In that case, it can be said that the displacement amount detection unit is configured including the external device. In that case, the image reading device is configured including the part that determines the amount of displacement in the external device.

FIG. 18 shows a schematic diagram of an image obtained by performing signal processing on the image obtained from the tracking sensor. Points extracted as feature points from an image captured at a certain time (t=0) are represented by black squares. Here, as an example, 1 square = 1 pixel (that is, the number of pixels of the tracking sensor is 5 x 5 = 25 squares), but after performing an average value of a plurality of pixels or a specific calculation, 1 square is formed representatively. You can After the time t' has passed from this state, the tracking sensor acquires the image again and extracts the black mass. Then, by comparing how the black squares (characteristic points) move, it is possible to calculate the amount of transport movement from time 0 to t'. The sheet conveying speed can be derived from the movement amount and an arbitrary unit time.

Next, a speed detection method when a tracking sensor is used as the speed detection sensor 109 will be described with reference to FIG. In the following description, the reference numerals shown in FIGS. 5 and 6 are used for the reference numerals attached to each member, and detailed explanations thereof are omitted. The tracking sensor can acquire the amount of displacement per unit time of the sheet 90 conveyed in the conveying path 110 at a constant speed. The unit time TR_t can be set arbitrarily, and it is desirable to set it to a resolution higher than the resolution with which the peak position of the magnetic signal acquired by the magnetic data detection unit 106 can be detected. From the transport movement information TR_x output from the tracking sensor and the unit time TR_t, the transport speed TR_s when advancing per unit time can be calculated. That is, it can be represented by TR_s=TR_x/TR_t from the relationship between distance and time. By calculating the conveying speed information at intervals of the unit time TR_t, it is possible to grasp the conveying state of the sheet 90 .

FIG. 19(a) shows a sheet 90 on which a string of magnetic ink characters is printed in an area 91. FIG. Here, only numerical values are shown in the area 91 for easy understanding. FIG. 19B is a graph plotting the transport speed TR_s when the sheet 90 is transported, and shows the transport speed fluctuation rate over time. When the conveying speed is stable, the conveying speed data is almost linear, but the speed may fluctuate at the moment when the sheet is sandwiched between the pair of conveying rollers. When there is such a speed fluctuation, the waveform fluctuates at the position where the speed fluctuation occurs, as shown in FIG. 19(b). The graph shown in FIG. 19B indicates that the conveying speed increases when the conveying speed fluctuation signal swings upward on the y-axis, and the conveying speed decreases when it swings downward.

FIG. 19(c) shows the output signal of the registration sensor 112 (see FIG. 5). A high signal is output when the sheet being conveyed touches the registration sensor 112 . In other words, the moment ts3 when the registration sensor 112 goes high is the timing when the sheet being conveyed hits the registration sensor. By using ts3 as a reference and counting the time or the output signal CLK of the encoder, it is possible to know how much the sheet has moved from the registration sensor 112 . Then, as shown in FIG. 19B, when there is a speed variation exceeding the reference threshold, it is possible to specify from ts4 at which position of the magnetic ink character the speed variation occurred.

The dotted line b1 is the first threshold for speed fluctuation, and the dotted line b2 is the second threshold. In the example of FIG. 19B, it can be seen that the speed fluctuation exceeds the first threshold value b1 at the position of the magnetic ink character "8", and the position can be specified. In this embodiment, there is only one point (position 92) at which the velocity variation exceeds the first threshold in order to explain the phenomenon in an easy-to-understand manner. However, if the conveyance control varies due to wear of the conveyance roller due to deterioration over time, the number of points at which the speed fluctuates increases, and there may be multiple points where the first threshold value is exceeded. In such a case, the magnetic data (detection signal waveform) is corrected for each generated point as described above. To make the phenomenon easier to understand, the example of FIG. 19 does not show the point at which the speed fluctuation exceeds the second threshold, but when the second threshold is exceeded, the processing described with reference to FIG. 16 is executed.

<Conveyance speed detection using encoder>
Next, a speed detection method and a magnetic ink character waveform correction method when an encoder is used as the speed detection sensor 109 shown in FIGS. 5 and 6 will be described with reference to FIG. An encoder is a sensor that detects the rotation (movement) direction, movement amount, and angle of a shaft. By generating pulses according to the movement amount and counting the pulses, the sheet conveying speed can be detected. Based on the detected sheet conveying speed, it is possible to synchronize reading of magnetic ink characters and perform correction processing, etc., as described above.

In this embodiment, as shown in FIG. 21, discs 280 each having a thin circular plate with fine slits are arranged along the transport path 110 . Then, by using a light emitting/receiving sensor 281 such as a U-shaped photointerrupter to acquire the detection pulse of the slit of the disc 280, the conveying speed of the sheet can be detected. Here, the disk 280 and the light emitting/light receiving sensor 281 constitute an encoder 283 . In this embodiment, the disk 280 is arranged at the same position as the driven roller 201a facing the conveying roller 201b (see FIG. 5). As a result, when the sheet is conveyed, it rotates synchronously due to friction, and the conveying behavior of the sheet when passing through the magnetic data detection unit 106 can be detected with higher accuracy.

The encoder 283 generates a clock (CLK) signal according to the speed of the sheet conveyed through the conveying path 110 at a constant speed. FIG. 20(a) shows the encoder signals when the magnetic ink character "8" is conveyed. From this encoder signal, it can be seen that the speed fluctuation has occurred between p3 and p4. When there is such a speed fluctuation, the magnetic ink character waveform is elongated as shown in FIG. 13(b). Therefore, when the amount of deviation from the reference CLK cycle, which is output when the sheet conveying speed does not fluctuate, exceeds the first threshold value, correction processing is started. The correction sequence when it is determined that the speed variation rate has exceeded the first threshold value is performed according to the procedure described with reference to FIG. 12 . Even when an encoder is used as the speed detection sensor 109, the same process is used to correct the magnetic ink character waveform. It is possible to detect the CLK cycle output from the encoder and calculate the correction value from the amount of deviation from the reference CLK.

<Arrangement of speed detection sensor>
Next, the arrangement of speed detection sensor 109 will be described with reference to FIG. 22, the same members as in FIGS. 5 and 6 are denoted by the same reference numerals, and detailed description thereof is omitted. Since the speed detection sensor only needs to be able to measure the conveying speed of the sheet, it may be arranged anywhere on the conveying path 110 . However, since the speed detection sensor 109 is arranged for the purpose of synchronizing with the signal of the magnetic data detection unit 106 as described above, the effect of the speed fluctuation of the sheet being conveyed is as small as possible in the vicinity of the magnetic data detection unit 106. Ideally, it should be placed in position.

In FIG. 22A, conveying rollers 201a and 201b constitute a first conveying roller pair, and conveying rollers 202a and 202b constitute a second conveying roller pair. When the front and rear of the sheet are sandwiched between the first and second roller pairs, fluctuations in speed during conveyance are less likely to occur, making it possible to accurately measure the conveyance speed of the sheet. Therefore, this condition can be satisfied by arranging the speed detection sensor 109 in the space L1 between the pair of conveying rollers as shown in FIG. 22(a). Further, by arranging the speed detection sensor 109 upstream of the magnetic data detection unit 106 in the conveying direction, the detection of the sheet conveying speed can be processed faster than the magnetic ink character decoding processing. It is possible to lead to transformation.

Further, if the speed information detected by the speed detection sensor 109 is to be accurately corrected when all the magnetic information read by the magnetic data detection unit 106 is decoded, it is desirable to satisfy the following conditions. That is, at the timing when the first character of the magnetic ink character string printed on the sheet is read by the magnetic data detection unit 106, the speed detection sensor 109 is at a position where the sheet conveying speed can be detected, and the sheet is printed. At the timing when the last character of the magnetic ink character string is read by the magnetic data detection unit 106, it is desirable that the speed detection sensor 109 is at a position where the sheet conveying speed can be detected. In other words, it is desirable to be arranged so that the conveying speed can be detected during the period between these timings. FIG. 22B is a diagram showing the moment when the first character of the magnetic ink character string hits the magnetic data detection unit 106 and the moment when the last character of the magnetic ink character string hits the magnetic data detection unit 106. . By arranging the speed detection sensor 109 in the range indicated by L2 in FIG. 22(b), the above condition can be satisfied and the correction accuracy of the decoding process can be improved.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to this embodiment, and various modifications and applications are possible. For example, in the above-described embodiment, the magnetic data correction processing unit 18 and the MICR processing unit 13 are provided in the main body of the information reading device 300, but the information reading device only detects magnetic data, corrects the magnetic data and performs MICR processing. may be performed by the host device 301 connected to the information reader (see FIG. 6). Similarly, image data may be sent from the information reading device 300 and OCR processing may be performed by the host device 301 . In the above case, the system including the information reader 300 and the host device 301 constitutes the information reader of the present invention.

In the above-described embodiment, an information reading apparatus having an image reading sensor 108 and an OCR processing unit 22 was described (see FIG. 6). The present invention can also be applied to an information reader that recognizes . The present invention includes all information reading apparatuses with such various improvements and modifications within the scope of the present invention.

13 magnetic ink character recognition (MICR) processing unit 22 optical character recognition (OCR) processing unit 106 magnetic data detection unit 108 image reading sensor 109 speed detection sensor

Claims (9)

a conveying means for conveying a sheet on which magnetic ink characters are printed along a conveying path;
a conveying speed detecting means for detecting a conveying speed of the sheet conveyed by the conveying means;
magnetic data detection means for detecting magnetic data of magnetic ink characters printed on the sheet conveyed on the conveying path and outputting a detection signal waveform;
magnetic data correcting means for correcting the detection signal waveform output from the magnetic data detecting means based on the conveying speed detected by the conveying speed detecting means;
and magnetic ink character recognition means for recognizing magnetic ink characters printed on the sheet from the detected signal waveform corrected by the magnetic data correction means. Further, there is provided control means for controlling the magnetic data correction means and the magnetic ink character recognition means, and the control means has a predetermined variation rate of the conveying speed detected by the conveying speed detecting means with respect to a reference value. When the one threshold value is exceeded, magnetic ink characters are recognized from the detected signal waveform corrected by the magnetic data correction means, and when the fluctuation rate is equal to or less than the first threshold value, the magnetic data correction means 2. An information reader according to claim 1, wherein magnetic ink characters are recognized from uncorrected detected signal waveforms. Further, there is provided an informing means for informing a user using the information reading device of a warning, and the control means, when the fluctuation rate exceeds a second threshold larger than the first threshold, the informing 3. The information reader according to claim 2, wherein the warning means is used to notify the user of the warning. Further, the control means has first and second discharge pockets into which the sheet conveyed on the conveying path is discharged, and the control means controls the change rate to exceed a second threshold larger than the first threshold. and controlling the conveying means to discharge the sheet to the second discharge pocket when the magnetic ink character recognition means fails to perform character recognition, and the variation rate is equal to or less than the second threshold value. 4. The apparatus according to claim 2, wherein the conveying means is controlled to discharge the sheet to the first discharge pocket when character recognition is successfully performed by the magnetic ink character recognition means. information reader. A character string of magnetic ink characters is printed on the sheet along the conveying direction in which the sheet is conveyed, and timing at which the first character of the character string in the conveying direction is detected by the magnetic data detection means. and the conveying speed detecting means is arranged at a position where the conveying speed of the sheet can be detected during a period between the timing at which the last character of the character string in the conveying direction is detected by the magnetic data detecting means. The information reader according to any one of claims 1 to 4. The conveying means has two pairs of conveying rollers that convey the sheet by passing the sheet between rollers. 6. The conveying speed detection means is arranged on each of the side and the downstream side, and the conveying speed detecting means is provided facing the conveying path between the pair of conveying rollers in the conveying direction. 1. The information reader according to item 1. 7. The conveying speed detecting means according to claim 1, wherein the conveying speed detecting means is provided facing the conveying path upstream of the magnetic data detecting means in the conveying direction in which the sheet is conveyed. Information reader. The information reading apparatus according to any one of claims 1 to 7, wherein the conveying speed detection means includes a tracking sensor that detects the conveying speed by tracking changes in a sheet image obtained by imaging the sheet. . Further, optical reading means for optically reading magnetic ink characters printed on the sheet and outputting image data, and optical character recognition means for recognizing the magnetic ink characters from the image data output from the optical reading means. correction based on the conveying speed detected by the conveying speed detecting means when the variation rate of the conveying speed detected by the conveying speed detecting means with respect to the reference value exceeds a predetermined third threshold value 9. The information reader according to claim 1, wherein the optical character recognition means recognizes the magnetic ink characters.

Images