JPH06314348A - Code reader - Google Patents

Abstract

PURPOSE:To provide a code reader which can accurately read the codes given on an original despite the curling or fluttering of the original caused during its transfer and despite the change of distance caused between the original and a sensor. CONSTITUTION:A code reader is provided with a reflective sensor 5 which detects the code of a white/black pattern given on the original transferred on a carrying path 10 by the rolls 1-4, an amplifier 6 which amplifies the output of the sensor 5, an A/D converter 7 which converts the output of the amplifier 6 into the digital multilevel value, and the binarizing circuits 30-34 which binarize simultaneously or in sequence the multilevel data at plural different slice levels to acquire the binary data corresponding to the detected code. These slice levels are set in consideration of the curling, fluttering and the vertical deviation of the original, and only the data that are kept in a prescribed range are supplied to a code recognizing circuit 40 as the binary data. Thus the code can be accurately read on the original.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a code reader for reading a document on which a code represented by a black and white pattern such as a bar code is written by a reflection type sensor while being conveyed by a conveying system.

More specifically, the present invention has a transport system,
A code represented by a black-and-white pattern exists on the original, and the analog data read by the reflective analog sensor is converted into digital multi-valued data, and the multi-valued data is provided with a slice level to be converted into binary data. The present invention relates to a code reading device which converts and discriminates a code based on the binary data.

[0003]

2. Description of the Related Art Conventionally, in a code reading device which has a conveyance system and a code represented by a black and white pattern is present on a document, and a code is read by a reflection type analog sensor, it is analog input and converted into digital data. When converting the converted multivalued data into binary data, the code data is converted into binary data at one slice level.

Further, in the conventional apparatus of this type, the vertical position of the original in the conveying system is not measured, but a black and white pattern on the original is simply conveyed by the reflective analog sensor while the original is being conveyed. Was being read.

[0005]

However, in the conventional device as described above, when the code is read by the reflection type analog sensor, the variation of the read analog value is caused by the change in the distance between the code of the document as the subject and the sensor. Therefore, there is a drawback that accurate binary data may not be obtained. That is, when the distance between the subject and the sensor is long, a sufficient amount of light due to reflection cannot be obtained, so white data approaches black data, and
When the distance between the subject and the sensor is short, the amount of light due to reflection is too large, and thus black data sometimes approaches white data. Therefore, there is a drawback that the code determination becomes difficult and the code determination takes time.

Furthermore, in the conventional apparatus as described above, when the vertical position of the original in the transport system changes, the output of the reflection type analog sensor also changes, and the code pattern cannot be read correctly. There were cases. In particular, if the conveyance speed is high, the conveyance performance will be reduced if the space between the vertical regulating members of the document in the conveyance system is narrowed, so that the space cannot be narrowed and the output of the reflective sensor changes greatly, and the correct code pattern is generated. In many cases, it was not possible to read.

In view of the above points, an object of the present invention is to curl an original document on which a black and white pattern code such as a bar code is entered, or the original document flaps during conveyance, and a sensor is used. It is an object of the present invention to provide a code reading device that can accurately read a code on an original even if the distance between the vertical directions of the original changes.

[0008]

In order to achieve the above object, a first embodiment of the present invention is an optical system for carrying a document and an optical system for optically detecting a code of a black and white pattern on the document being carried. A sensor, digital conversion means for converting the output data of the optical sensor into digital multi-valued data, and the digital multi-valued data of the output of the digital conversion means is binarized by a number of slice levels And a binarizing means for determining whether or not the length of the black or white part is within a predetermined prescribed range and outputting only the binary data of the affirmative determination as the data of the detection code. And

In order to achieve the above-mentioned object, a second embodiment of the present invention is a conveying system for conveying a document, an optical sensor for optically detecting a code of a black-and-white pattern on the conveyed document, and Digital converting means for converting the output data of the optical sensor into digital multi-valued data, and, when the digital multi-valued data of the output of the digital converting means is binarized by a plurality of slice levels, a black-and-white part at a change point of the black-and-white part Is binarized by deciding the length of the code, and one of the binarized data is selected and outputted as code data representing black and white.

In order to achieve the above-mentioned object, a third embodiment of the present invention comprises a conveying system for conveying a document, an optical sensor for optically detecting a code of a black-and-white pattern on the conveyed document, and 2 according to a distance sensor that measures the distance between the optical sensor and the document, and a slice level obtained by correcting the output data of the optical sensor with the output data of the distance sensor.
And a binarizing means for digitizing.

Furthermore, the present invention preferably has, as one aspect thereof, at least one of the plurality of slice levels.
One may be a curvilinear slice level having a correction according to the curl of the document or the flapping of the document.

Further, as one aspect of the present invention, preferably, in the case where the values of the plurality of slice levels are not reversed from each other, the plurality of slice levels of the binary data for which the positive determination is obtained are sandwiched. When there is a slice level of binary data for which the affirmative judgment cannot be obtained,
It can be characterized in that it further comprises a judging means for judging that there is a failure.

[0013]

In the first embodiment of the present invention, a plurality of slice levels (threshold values) are set in consideration of the fact that the analog value read by the sensor varies due to the change in the distance between the object and the sensor. , Converts multi-valued data to binary data at each slice level, measures the length of a certain black or white part according to each slice level, and makes a code judgment. Get results. Further, since the above-mentioned variation appears remarkably when the original is curled, the code is discriminated by converting into binary data at the slice level of a curve having a correction according to the original curl.

Further, in the second embodiment of the present invention, the analog value read by the sensor varies due to the change in the distance between the object and the sensor, that is, the original document flickers while being conveyed through the conveying system. In consideration of the above, set a plurality of slice levels, measure the length of the black or white part at each slice level, and compare the output results to output the correct white or black result, Get the proper code results.

Further, according to the third aspect of the present invention, a distance sensor for measuring the vertical position of the document being conveyed at the reading position of the reflection type sensor is provided, and the output of the reflection type sensor is the output of the distance sensor. Correction is performed, and thereby the code pattern is accurately read.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings.

(First Embodiment) FIG. 1 shows a schematic configuration of a code reading apparatus according to a first embodiment of the present invention. In FIG. 1, reference numerals 1, 2, 3 and 4 are conveying rollers which are rotated by a drive motor (not shown) to send a document, 5 is a reflection type sensor for reading a code on the document, and 6 is a reflection type sensor such as a photocoupler. An amplifier for amplifying the analog data read in 5 is an A / D (analog / digital) converter 7 for converting the analog data sent from the amplifier 6 into digital multi-valued data.
Further, reference numerals 30, 31 and 32 are binarization circuits, and 40 is a code recognition circuit.

Numerals 33 and 34 are binarization circuits used in the second embodiment described later.

FIG. 2 shows an example of an original and a code read by the apparatus shown in FIG. In FIG. 2, reference numeral 8 is a document on which a code is printed, and 9 is a code on the document 8.

FIG. 3 is an enlarged view of the portion of the conveying path 10 shown in FIG. In FIG. 3, 11 is an original document being conveyed in the middle portion of the conveyance path 10, 12 is an original document being conveyed in the upper part of the conveyance path 10, and 13 is an original document being conveyed in the lower part of the conveyance path 10. Show.

FIG. 4 shows the output of the A / D converter 7 and the slice level when the distance between the sensor 5 in FIG. 1 and the original 8 in FIG. 2 is relatively short. In FIG. 4, 14 is the output waveform of the A / D converter 7 when the document 8 passes through the intermediate portion of the paper transport path 10, and 15 is the output waveform when the distance between the sensor 5 and the document 8 is relatively short. ,
Reference numeral 16 is a slice level for binarizing the output waveform 14, and 17 is a slice level for binarizing the output waveform 15.

FIG. 5 shows the output of the A / D converter 7 and the slice level when the distance between the sensor 5 in FIG. 1 and the document 8 in FIG. 2 is relatively long. 5, 14 is an output waveform when the document 8 passes through the intermediate portion of the paper transport path 10 as in FIG. 4, 18 is an output waveform when the distance between the sensor 5 and the document 8 is relatively long, 16 4 is a slice level for binarizing the output waveform 14, and 19 is a slice level for binarizing the output waveform 18.

In the above structure, the original 8 on which the code 9 is printed is conveyed like the original 11 in FIG. 3 through the intermediate portion of the paper conveying path 10 between the rollers 1 and 2 or the rollers 3 and 4. When the detection area of the sensor 5 is reached, the code 9
Data is detected by the sensor 5 and amplified by the amplifier 6,
It is converted into digital multi-valued data by the A / D converter 7. Since the waveform of this multi-valued data becomes like the output waveform 14 shown in FIGS. 4 and 5, the number of codes is counted by using the slice level 16 in the binarization circuit 30 in the subsequent stage, and the number is defined to be allowable. Whether it is within the range or not is determined, and if the determination is affirmative, conversion processing into binarization is performed to enable black-and-white pattern recognition.

The original 8 on which the code 9 is printed is
When the lower part of the paper conveyance path 10 between the rollers 1 and 2 or the rollers 3 and 4 is conveyed like the original 13 in FIG. 3 and reaches the detectable area of the sensor 5, the data of the code 9 is transferred to the sensor 5. Is detected by, is amplified by the amplifier 6, and is converted into digital multilevel data by the A / D converter 7. The waveform of this multi-valued data has an output waveform 18 as shown in FIG. 5 because the distance between the sensor 5 and the original 8 is long and a sufficient amount of light cannot be obtained from the sensor 5, so that the binarization in the latter stage is performed. The circuit 31 counts the number of codes using the slice level 19, judges whether or not the number is within the specified permissible range, and if the judgment is affirmative, 2
Performs conversion processing to digitization and enables black and white pattern recognition. In order to recognize the black-and-white pattern with the output waveform 18, it is impossible to recognize the pattern with the slice level 16 for the output waveform 14 obtained when the document 8 is conveyed in the intermediate portion of the paper conveyance path 10. Can be seen from FIG.

Further, the original 8 on which the code 9 is printed is
When the upper portion of the paper conveyance path 10 between the rollers 1 and 2 or the rollers 3 and 4 is conveyed like the original 12 in FIG. 3 and reaches the detectable area of the sensor 5, the data of the code 9 is detected by the sensor 5. It is detected, amplified by the amplifier 6, and converted into digital multilevel data by the A / D converter 7. The waveform of the multi-valued data has an output waveform 15 shown in FIG.
Therefore, the number of codes is counted by using the slice level 17 in the binarization circuit 32 in the subsequent stage, and it is judged whether or not the number is within the specified allowable range. Performs conversion processing to enable black and white pattern recognition. In addition,
In order to recognize the output waveform 15 in the black-and-white pattern, the pattern recognition cannot be performed by using the slice level 16 for the output waveform 14 obtained when the document 8 is conveyed through the intermediate portion of the paper conveyance path 10. It can be seen from FIG. 4 that there is.

That is, in the present embodiment, the binarization circuit 30 is used.
To 32 and the code recognition circuit 40 in the subsequent stage, three slice levels for passing the upper part of the paper transport path 10, passing the middle part of the paper transport path 10, and passing the lower part of the paper transport path 10 are set. Binarization processing and code recognition are performed simultaneously by using them at the same time, and if even one of them is recognized, it is output as a code result.

Further, instead of the above-mentioned parallel processing, a buffer memory for temporarily storing multi-valued data is connected to the output end of the A / D converter 7, and the above-mentioned plurality of slice levels are set to 1
If it is constructed such that the codes are sequentially switched and used until the codes can be recognized one by one, the plurality of binarization circuits 30, 31,
32 can be replaced with one binarization circuit.

[0028]

[Table 1]

Table 1 above is a comparison table of the code recognition result at each slice level and the comprehensive judgment result thereof in the first embodiment of the present invention. It should be noted that the circle mark is a case where the mark can be recognized, and the X mark is a case where the mark cannot be recognized. In Table 1, the slice level 17 is described in the first embodiment,
The original 8 is conveyed on the upper side of the conveying path 10 like the original 12 in FIG. 3, and the slice level and the slice level 16 when the distance between the sensor 5 and the original 8 is short are described in the first embodiment. The slice level and the slice level 19 for the case where the document 8 is transported in the middle portion of the transport path 10 as the document 11 of FIG. 3 have been described in the first embodiment.
This is a slice level for the case where the original 8 is conveyed on the lower side of the conveying path 10 like the original 13 in FIG. 3 and the distance between the sensor 5 and the original 8 is long.

As shown in Table 1, only the slice levels 16 and 17 and 19 or 16 have the code 9 on the original 2
If the digitizing circuits 30 to 32 can recognize the code, the code recognizing circuit 40 determines that the original 8 has been conveyed through the intermediate portion of the conveying path 10 and outputs the code recognition result. Slice levels 16 and 17 or only 17 are code 9 on the manuscript
If it can be recognized by the digitizing circuit, the code recognition circuit 40 determines that the original 8 has been conveyed on the upper portion of the conveyance path 10 and outputs the code recognition result. Slice levels 16 and 1
If only 9 or 19 can recognize the code 9 on the manuscript by the binarizing circuit, the code recognizing circuit 40 judges that the manuscript 8 is conveyed under the conveying path 10 and recognizes the code. Output the result.

On the other hand, if all of the slice levels 16, 17, and 19 cannot recognize the code 9 on the original by the binarizing circuit, it is judged that there is no code, and the code recognizing circuit 40 indicates that there is no code. Print the output. However, when the slice level 17 and 19 recognize the code 9 but only the slice level 16 cannot recognize the code 9, such a situation cannot occur, and the code recognition circuit 40 causes the sensor 5 to detect the code 5. It is judged as a partial failure, and an output indicating that it is a failure is output.

(Second Embodiment) FIG. 6 shows an original used in the second embodiment of the present invention. In FIG. 6, 9 is a code printed on a document, 20 is a document on which the code 9 is printed and curled, and 21 is a document 2 on which the code 9 is printed.
The original is curled on the side opposite to 0.

FIG. 7 shows the state of the distance from the sensor 5 when the curled document 20 in FIG. 6 is being conveyed through the sheet conveying path 10.

FIG. 8 shows a sensor 5 which detects the code 9 printed on the original 20 curled outward in FIG.
The output waveform from is shown. In FIG. 8, 22 is the output waveform of the code 9 printed on the uncurled original (not shown), and 23 is the output waveform of the code 9 printed on the curled original 20. Reference numeral 24 is a constant linear slice level for binarizing the output waveform 22, and 25 is a curve slice level whose numerical value changes with time for binarizing the output waveform 23.

FIG. 9 shows the sensor 5 that detects the code 9 printed on the original 21 curled in FIG.
The output waveform from is shown. In FIG. 9, 22 is the output waveform of the code 9 printed on an uncurled original (not shown) as in FIG. 8, and 26 is the curled original 21.
The output waveform of the code 9 printed on the label 24 is a constant linear slice level for binarizing the output waveform 22, and 27 is a numerical value that changes over time for binarizing the output waveform 26. This is the slice level of the curve.

In the structure of FIG. 1, when the original 20 curled to the outside is conveyed through the paper conveyance path 10 and reaches the detectable area of the sensor 5 as shown in FIG. Detected, amplified by amplifier 6, A / D
It is converted into digital multi-valued data by the converter 7. In the waveform of this multi-valued data, since the document 20 is curled as shown in FIG. 7, the distance between the sensor 5 and the document 20 is long at the leading edge of the document, and the sensor 5 and the document 20 are at the trailing edge of the document.
Since the distance between and becomes short, the output waveform 23 shown in FIG. 8 is obtained. In this case, the binarization circuit 33 counts the number of codes using the slice level 25 of the curve, and the number is within the specified allowable range. If it is affirmative, a conversion process to binarization is performed to enable black-and-white pattern recognition. In order to recognize the output waveform 23 in the black and white pattern, the pattern recognition cannot be performed by using the slice level 24 for the output waveform 22 of the code 9 printed on the uncurled original (not shown). It can be seen from FIG. 8 that

When the original 21 curled inward is conveyed through the paper conveying path 10 and reaches the detectable area of the sensor 5, the data of the code 9 is detected by the sensor 5 and amplified by the amplifier 6. It is converted into digital multi-valued data by the A / D converter 7. The waveform of this multivalued data is
Since 1 is curled as shown in FIG. 6, the distance between the sensor 5 and the document 21 is short at the leading edge of the document, and the distance between the sensor 5 and the document 21 is long at the trailing edge of the document.
Since the output waveform 26 shown in FIG. 9 is obtained, in this case, the binarizing circuit 34 counts the number of codes using the slice level 27, judges whether the number is within a specified allowable range, and makes an affirmative judgment. In that case, conversion processing to binarization is performed to enable black-and-white pattern recognition. In order to recognize the black and white pattern of the output waveform 26, if the slice level 24 for the output waveform 22 of the code 9 printed on the uncurled original (not shown) is used, the pattern cannot be recognized. It can be seen from FIG. 9 that

That is, in the present embodiment, the binarization circuit 3
0, 33, 34 and the code recognition circuit 40 in the subsequent stage show the slice level 25 as shown in FIG. 8 for the curled document 20 and FIG. 9 for the curled document 21 on the opposite side. Slice level 27 like this, 2 like slice level 24 for uncurled originals not shown
Binary processing and code recognition are performed at the same time using the slice level of each curve and the slice level of one straight line, and if even one of them is recognized, it is output as a code result.

It is also preferable to combine the first and second embodiments of the present invention as shown in FIG. In addition, as described in the first embodiment of the present invention, A /
If a buffer memory for temporarily storing multi-valued data is connected to the output end of the D converter 7 and the plurality of slice levels described above are sequentially switched and used until the code can be recognized one by one, the above two Thresholding circuits 30, 3
The circuits of 2, 33 or 30 to 33 can be replaced with a single binarization circuit.

(Third Embodiment) FIG. 10 shows the enlargement of the portion of the conveying path and the circuit configuration of the third embodiment of the present invention. Figure 1
In 0, 5 is a reflection type sensor, 10 is a conveyance path for conveying an original, and 111 is a flapping original being conveyed on the conveyance path 10. Reference numeral 6 is an amplifier, and 7 is an A / D converter. Reference numeral 141 is a buffer memory for temporarily storing the output of the A / D converter, 142 is a binarization circuit for binarizing the multivalued data read from the buffer memory 141 by selectively using one of a plurality of slice levels, 143. Is a counter for counting the number of output pulses of the binarization circuit 142,
144 compares the count number of the counter 143 with a specified value, and when it is within the specified value, outputs the output of the binarization circuit 142 as code recognition data. The comparator 144 switches the slice level 145 according to the comparison result.

FIG. 11 shows the output of the A / D converter 7 and the slice level of the original 111 which is flapping in FIG. In FIG. 11, reference numeral 112 denotes an output waveform when the flapping original document 111 passes, 113 and 11
4,115 are a plurality of predetermined slice levels,
Reference numerals 116, 117, and 118 are black-and-white portion change points from white data to black data, and reference numerals 119, 120, and 121 are black-and-white portion change points from black data to white data.

In the above structure, the code 9 is used as shown in FIG.
When the fluttering original 111 printed with is conveyed through the paper conveyance path 10 between the rollers 1 and 2 or between the rollers 3 and 4 (see FIG. 1) and reaches the detectable area of the sensor 5, The data of the code 9 on the manuscript is detected by the sensor 5, amplified by the amplifier 6, and converted into digital multi-valued data by the A / D converter 7, and the output waveform 112 shown in FIG. 11 is obtained. The output waveform 112 is sent to the binarization circuit 142. First, for the slice level 113, the counter 143 counts the number of data between the black-and-white part change point 118 and the black-and-white part change point 119, and the number is the specified allowable range. Whether or not it is inside is judged by the comparator 144. Similarly, with respect to the slice level 114, the number of data between the black-and-white part change point 117 and the black-and-white part change point 120 is counted, and it is determined whether or not the number is within the specified allowable range. Further, for the slice level 115, the number of data between the black-and-white part change point 116 and the black-and-white part change point 121 is counted, and it is determined whether or not the number is within the specified allowable range. As described above, the data at three locations are compared, and if there is data whose count number is within the specified permissible range, the comparator 14 regards it as data for that section.
Output from 4. The above operation is performed every time a black-and-white part change point comes, and finally the code is recognized by the code recognition circuit 14 in the subsequent stage.
Determine with 5.

(Fourth Embodiment) FIG. 12 shows the output of the A / D converter 7 and the slice level of the flapping original 111 in the fourth embodiment of the present invention. Figure 1
In FIG. 2, 122 is an output waveform when an unfluttered document passes through an intermediate portion of the paper transport path 10 and 1
23 is an output waveform when the flapping original 111 passes, 124, 125 and 126 are slice levels, 12
7, 128, 129, and 130 are points near the black-and-white portion change from black data to white data, or from white data to black data.

In the circuit configuration of FIG. 10, an unfluttered original document on which the code 9 is printed is conveyed through the intermediate portion of the paper conveying path 10 between the rollers 1 and 2 or the rollers 3 and 4. When the sensor 5 reaches the detectable area, the code 9 data is detected by the sensor 5 and the amplifier 6
Are amplified by and converted into digital multi-valued data by the A / D converter 7. The waveform of this multi-valued data becomes like the output waveform 122 of FIG. 12, and the slice levels 124, 12
It becomes possible to recognize a black and white pattern by performing conversion processing to binarization with any one of 5, 126.

On the other hand, the fluttering original 111 on which the code 9 is printed is the rollers 1, 2, or the rollers 3, 3.
When the paper 9 is conveyed through the paper conveyance path 10 between 4 and reaches the detectable area of the sensor 5, the data of the code 9 is detected by the sensor 5, amplified by the amplifier 6, and converted into digital multi-valued data by the A / D converter 7. To be converted. In the waveform of the multi-valued data, the distance between the sensor 5 and the fluttering original 111 is long, and the distance between the sensor 5 and the fluttering original 111 is short. Sensor 5
Since there is a mixture of too much light due to reflection in Fig. 1,
2 becomes the output waveform 123, and the slice level 12
It is impossible to recognize a black-and-white pattern after the conversion processing into the binarization with only one slice level in any of 4, 125 and 126.

That is, in order to recognize the output waveform 123, it is necessary to output a white or black result for each point near the change in the black and white region. Before the black and white region change near point 127, the number of data is counted at the slice levels 124 and 125, and it is judged whether or not the number is within the specified allowable range. If the result is affirmative, conversion processing to binarization is performed. Enables pattern recognition. That is, in this portion, the information at the slice level 126 is ignored and the slice levels 124, 12 are
The information in 5 is valid. After that, slice level 126
Ignores the information of the slice level 126 until detects a point near the black-and-white portion change.

Similarly, between the black and white part change near point 127 and the black and white part change near point 128, the slice level 12
At 5,126, the number of data is counted, and it is determined whether the number is within a specified allowable range. If the determination is affirmative, conversion processing to binarization is performed, and a black-and-white pattern can be recognized. That is, in this part, the information at the slice level 124 is ignored,
The information at the slice levels 125 and 126 is validated.
After that, the information at the slice level 124 is ignored until the slice level 124 senses a point near the black-and-white portion change.

As described above, when the multi-valued data from the A / D converter 7 reaches the black and white part change vicinity point 127,
The data obtained from the three slice levels up to now are compared, and the slice level for which the black-and-white pattern cannot be recognized is ignored until a point near the black-and-white portion change comes thereafter. Multi-valued data shows the black and white part change near points 128,129,
Similarly, when the number reaches 130, the data obtained from the three slice levels up to now are compared, and the slice level for which the black-and-white pattern cannot be recognized is ignored until a point near the black-and-white portion change comes thereafter.

As described above, the black-and-white pattern recognition is performed for each point near the change in the black-and-white portion, the slice level for which the black-and-white pattern cannot be recognized is ignored until the point near the change in the black-and-white portion comes thereafter, and the appropriate code is recognized by the code recognition circuit 145. Get recognition results.

[0050]

[Table 2]

Table 2 above is a comparison table of the code recognition result at each slice level in the above-described fourth embodiment of the present invention and the comprehensive judgment result thereof. It should be noted that the circle mark is a case where the mark can be recognized, and the X mark is a case where the mark cannot be recognized. In Table 2, the slice level 124 is the slice level for the portion where the flapping original 111 is conveyed on the upper side of the conveying path 10 and the distance between the sensor 5 and the original 111 is short, as described in the fourth embodiment. The slice level 125 is the slice level for the intermediate portion in which the fluttering original 111 is conveyed through the intermediate portion of the conveying path 10 described in the fourth embodiment, and the slice level 126 is the slice level in the fourth embodiment. This is the slice level for the portion where the fluttering original document 111 is conveyed through the lower portion of the conveyance path 10 and the distance between the sensor 5 and the original document 8 is long, as described above.

As shown in Table 2, the slice level 124
If 125 and 126 can recognize the code 9 on the original, it is determined that the fluttering original 111 has been conveyed without fluttering in the intermediate portion of the conveying path 10, and the code change near point The binarization result in between is output from the comparator 144. When all of the slice levels 124, 125, 126 cannot recognize the code 9, it is determined that the code does not exist, and the comparator 144 outputs an output of no code.

However, the code 9 could be recognized at the two slice levels, but the code 9 could not be recognized at the remaining one slice level, or the code 9 could be recognized at the one slice level. However, when the code 9 cannot be recognized in the remaining two slice levels, the user can select with a switch (not shown) which to determine the code as valid.

(Fifth Embodiment) FIG. 13 shows an original used in the fifth embodiment of the present invention. In FIG. 13, 9 is a code printed on the original, 131 is a curled original on which the code 9 is printed, 132 is an original on which the code 9 that is curled on the opposite side of the original 131 is printed. is there.

FIG. 14 shows an output waveform from the sensor 5 which detects the code 9 when the curled original 131 in FIG. 13 or the curled original 132 on the opposite side flaps in the conveying path 10. Show. In FIG. 14, reference numeral 122 denotes a code 9 printed on a not-fluttering original document.
3 is an output waveform of the code 9 when the curled original 131 or the curled original 132 on the opposite side flaps in the conveyance path 10. 125,1
34 and 135 are slice levels 127, 128 and 12
Reference numerals 9 and 130 are points near the black-and-white portion change from black data to white data or from white data to black data.
In addition, 125 is a linear slice level, and 134 and 1
35 is the slice level of the curve.

In the circuit structure of FIG. 10, the curled original 131 on which the code 9 is printed or the curled original 132 on the opposite side is the paper between the rollers 1 and 2 or between the rollers 3 and 4. When it is conveyed without fluttering in the middle portion of the conveyance path 10 and reaches the detectable area of the sensor 5, the data of the code 9 is detected by the sensor 5, amplified by the amplifier 6, and digitally converted by the A / D converter 7. Converted to value data. The waveform of this multilevel data is the output waveform 1 of FIG.
22 and slice levels 125,134,1
It is possible to perform black-and-white pattern recognition by performing conversion processing to binarization with any one of 35.

On the other hand, the curled original 131 on which the code 9 is printed or the original 13 curled on the opposite side.
When the paper 2 is conveyed by fluttering the paper conveyance path 10 between the rollers 1 and 2 or the rollers 3 and 4 and reaches the detectable area of the sensor 5, the data of the code 9 is detected by the sensor 5 and the amplifier It is amplified in 6 and converted into digital multi-valued data in the A / D converter 7. The waveform of this multi-valued data is
A portion where the sensor 5 and the original 131 or the original 132 have a long distance and a sufficient amount of light cannot be obtained by the sensor 5, and the sensor 5
14 and the original 131 or the original 132 are short, and a portion of the sensor 5 where the amount of light due to reflection is too large is mixed, the output waveform 133 in FIG.
In any of 25, 134, and 135, only one slice level performs conversion processing into binarization, and it becomes impossible to recognize a black-and-white pattern.

In other words, in order to recognize this output waveform 133, it is necessary to output the result of white or black at the point near the change in the black and white region. Before the black and white part change near point 127, the number of data is counted at the slice levels 134 and 125, and it is determined whether the number is within a specified allowable range. If the determination is affirmative, conversion processing to binarization is performed. Enables pattern recognition. That is, in this portion, the information at the slice level 135 is ignored and the slice levels 134, 12
Validate the information in item 5. After that, until the slice level 135 detects a point near the change in the black and white part, the slice level 1
Ignore 35 information.

Similarly, between the black and white part change near point 127 and the black and white part change near point 128, the slice level 12
At 5,135, the number of data is counted, and it is determined whether the number is within the specified permission range. If the determination is affirmative, conversion processing to binarization is performed, and the black-and-white pattern can be recognized. That is, in this part, the information at the slice level 134 is ignored,
The information at the slice levels 125 and 135 is validated.
After that, the information at the slice level 134 is ignored until the slice level 134 senses a point near the black-and-white portion change.

As described above, when the multi-valued data from the A / D converter 7 reaches the black and white part change vicinity point 127,
The data obtained from the three slice levels up to now are compared, and the slice level for which the black-and-white pattern cannot be recognized is ignored until a point near the black-and-white portion change comes thereafter. Multi-valued data shows the black and white part change near points 128,129,
Similarly, when the number reaches 130, the data obtained from the three slice levels up to now are compared, and the slice level for which the black-and-white pattern cannot be recognized is ignored until a point near the black-and-white portion change comes thereafter.

As described above, the black-and-white pattern recognition is performed for each point near the black-and-white portion change, and the slice level for which the black-and-white pattern cannot be recognized is ignored until the point near the black-and-white portion change comes thereafter, and the appropriate code is recognized by the code recognition circuit 145. Get results.

(Sixth Embodiment) Next, a sixth embodiment of the present invention will be described with reference to FIGS. 15, 16 and 17. FIG. 15 shows a schematic configuration of a code reading device according to a sixth embodiment of the present invention, (A) of which is a front view and (B) thereof which is a plan view. In FIG. 15, reference numerals 201 to 204 denote transport rollers that are rotated in the direction of the arrow by a drive motor (not shown) to transport the document 211 (or 212). Reference numeral 205 is an upper guide plate that guides the document, and 206 is a lower guide plate that guides the document. 207 is an LED for illuminating the original
(Light emitting diode), 208 is a lens for guiding the reflected light from the document to the light receiving element, 209 is a light receiving element for photoelectrically converting the amount of the reflected light from the document into an electrical output, and 210 is the vertical position of the document in the conveying system. It is a distance sensor that detects whether it exists. An ultrasonic sensor or the like can be applied to the distance sensor 210 in addition to the photo sensor. The distance sensor 210 is arranged in parallel with the light receiving element 209 in the direction perpendicular to the document feeding direction, and when the photo sensor is used, it is located at a position deviated from the passing position of the cord 213. Will be placed. Reference numeral 211 denotes a document that is being transported in the center of the transport system, and reference numeral 212 is a curled document that is being transported in the transport system deviating from the center.

FIG. 16 shows an example of originals and codes sent by the transport system of FIG. 15, and reference numeral 213 is the same codes shown in black and white patterns on the originals 211 and 212.

FIG. 17 shows the relationship between detection output waveforms and codes when the originals 211 and 212 shown in FIG. 16 are conveyed as shown in FIG. 15 and detected by the light receiving element 209. In FIG. 17A, 214 is an uncurled original 211.
Is output from the light receiving element 209, 215 is a slice level determined from the output of the distance sensor 210 at this time, and 216 is black and white produced by binarizing the output 214 of the light receiving element 209 by the slice level 215. Is the code represented by the pattern. Further, in FIG. 17B, 217 is the output of the light receiving element 209 when the curled original 212 is conveyed, 218 is the slice level determined from the output of the distance sensor 210 at this time, and 219 is the light receiving element 209. Is a code represented by a black-and-white pattern created by binarizing the output 217 of S.

FIG. 18 shows the circuit configuration of this embodiment. The output of the light receiving element 209 is amplified by the amplifier 241 and becomes multi-valued data as shown at 214 and 217 in FIG. 17 by the A / D converter 243, and is sent to the CPU (central processing unit) 245 which functions as a binarization circuit. input. On the other hand, the output of the distance sensor 210 is amplified by the amplifier 242, becomes a multi-valued slice level as shown by 215 and 218 in FIG. 17 in the A / D converter 244, and is input to the CPU 245. C
The PU 245 binarizes the light receiving element output value from the A / D converter 243 at the slice level from the A / D converter 244 to obtain a binary code output as indicated by 216 and 219 in FIG. In this example, the digitization is performed by the A / D converter and then the binarization is performed, but as described later, it is also possible to directly obtain the binary code from the analog output by using the comparator.

Next, the overall operation of this embodiment having the above configuration will be described. When the uncurled original 211 is conveyed from the right side to the left side in FIG. 15 by the conveying rollers 201 to 204, the light receiving element 209 causes the waveform 214 of FIG. The voltage shown in is output. Further, at this time, the distance sensor 210 outputs the voltage indicated by the linear broken line 215 in FIG. 17A as an output according to the vertical distance of the document in the transport system. In the present embodiment, the output 214 of the light receiving element 209 and the output 215 of the distance sensor 210 are the A / D converter 24.
Input to the CPU 245 through 3,244
45 compares these two inputs and recognizes that the code 216 in FIG. 17A exists on the original.

Further, when the curled original 212 is conveyed from the right side to the left side of FIG. 15 by the conveying rollers 201 to 204, the light receiving element 209 has the waveform shown in FIG. The voltage indicated by 217 is output. At this time, the original 212 is curled, and the leading end of the original 212 passes through the lower portion of the transport system as shown by the broken line in FIG. 15, but as the original 212 is transported, it passes through the central portion of the transport system. Therefore, the light receiving element 20
As shown by the output waveform 217 of No. 9, the output has an inclination as a whole as compared with the output 214 of the uncurled document. The output of the distance sensor 210 at this time is the original 2
When 12 passes through the lower part of the carrier system, the voltage becomes low when it passes through the lower part, and becomes high when it passes through the upper part, so that the voltage as indicated by the broken line 218 in FIG. 17B is output.

The above two outputs 217 and 218 are input to the CPU 245 through the A / D converters 243 and 244, and the CPU 245 compares the outputs and outputs the code 219.
Recognize. At this time, even if the output 217 of the light receiving element 209 has a tilt, the output 218 of the distance sensor 210 also has a similar tilt, so that the code 219 that does not curl passes through the central portion in the transport system. Code 216
Produces the same result as.

(Seventh Embodiment) FIGS. 19 and 20 show a seventh embodiment of the present invention. Here, 220 is a comparator for comparing the analog output (217) of the light receiving element 209 and the analog output (218) of the distance sensor 210, 22
A CPU 1 receives the digital output of the comparator 220 and encodes a black-and-white pattern on a document. 22
2 is a digital output of the comparator 220.

In the above structure, when the curled document 212 is conveyed to the position of the light receiving element 209 as in the sixth embodiment, the light receiving element 209 and the distance sensor 210 are moved.
The voltages indicated by the waveforms 217 and 218 in FIG. 20 are output from the comparator 220, and the two voltages are compared by the comparator 220.
The output 222 is sent out by digitizing. CPU22
1 can correctly recognize the black-and-white pattern 213 on the curled document 212 by taking in the output 222.

In the present embodiment, the comparator 220 compares the analog output of the light receiving element 209 and the analog output of the distance sensor 210 and binarizes them. However, as shown in FIG. 21, the output of the distance sensor 210 is an inverter. Alternatively, the output of the light receiving element 209 may be inverted by the (inversion circuit) 231 and added by the adder 232, and the addition result may be binarized by the converter 233 with a fixed slice level. That is, the difference value between the output 217 of the light receiving element 209 and the output 218 of the distance sensor 210 may be binarized at a fixed slice level.

(Eighth Embodiment) FIG. 22 shows the structure of an eighth embodiment of the present invention. In the sixth embodiment of the present invention, the light receiving element 20 for reading a black-and-white pattern on an original document.
9 and a distance sensor 210 for detecting which position in the vertical direction the document passes in the transport system, as shown in FIG. However, there are cases where such an arrangement is physically impossible.

In this case, the original is displaced in the vertical direction in the conveying system because the original is curled, and the fact that the same deviation occurs downstream of the conveying rollers of the same structure is utilized. As shown in FIG. 22, the light receiving element 209 and the distance sensor 210 are separated from each other in the transport system by the other transport rollers 203, 20.
No. 4 and 251, 252 are separately arranged at the same positions, respectively, and the time difference between the detection outputs of both is corrected based on the transport speed of the transport system and the distance in the transport direction of the both, so that the sixth embodiment As in the example, it is possible to recognize the correct code pattern.

[0074]

As described above, according to the present invention,
Since binarization is performed using a plurality of slice levels, the output of the reflective sensor can be accurately binarized even if the distance between the document on which the code is printed and the reflective sensor changes due to curl or flutter of the document. There is an effect that it can be converted into data and the recognition probability of the code can be improved.

Further, according to the present invention, when the document is vertically displaced in the conveying system, the distance sensor measures the amount of displacement and the output of the reflection type sensor for reading the black and white pattern on the document is binary. Since the binarization is performed by using the slice level according to the shift amount, the code represented by the black and white pattern on the document can always be read correctly.

[Brief description of drawings]

FIG. 1 is a cross-sectional view including a block diagram showing a schematic configuration of a code reading device according to a first embodiment of the present invention.

FIG. 2 is a plan view showing an example of a document and a code read by the apparatus of FIG.

FIG. 3 is an enlarged cross-sectional view in which a portion of the conveyance path of FIG. 1 is enlarged.

FIG. 4 is a waveform diagram showing an output waveform of the sensor and a slice level used when the distance between the reflection type sensor of FIG. 1 and a document is short.

5 is a waveform diagram showing an output waveform of the sensor and a slice level used when the distance between the reflection type sensor of FIG. 1 and a document is long.

FIG. 6 is a perspective view showing an example of a curled document conveyed in a second embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a state of the distance between the reflective sensor and the original when the curled original of FIG. 6 is being conveyed through a paper conveyance path.

FIG. 8 is a waveform diagram showing an output waveform of a reflective sensor that detects a code on the original when the original curled in FIG. 6 is conveyed and a slice level used at that time.

9 is a waveform diagram showing an output waveform of a reflective sensor that detects a code on the original when the original curled in FIG. 6 is conveyed and a slice level used at that time.

FIG. 10 is a sectional view including a block diagram showing an enlargement and a circuit configuration of a portion of a conveyance path according to a third embodiment of the present invention.

11 is an A / D for the flapping original of FIG.
It is a waveform diagram which shows the output waveform of a converter and the slice level used.

FIG. 12 is a waveform diagram showing an output waveform of an A / D converter and a slice level used for a flapping original in a fourth embodiment of the present invention.

FIG. 13 is a perspective view showing an example of a curled document conveyed in a fifth embodiment of the present invention.

FIG. 14 is a waveform diagram showing an output waveform of the A / D converter and a slice level to be used when the curled document of FIG. 13 is conveyed on a paper conveyance path.

FIG. 15 is a front view (A) and a plan view (B) showing a schematic configuration of a main part of a code reading device according to a sixth embodiment of the present invention.

16A and 16B are a plan view and a perspective view showing an example of a document and a code sent by the transport system of FIG.

17 is a waveform diagram showing that a code is recognized from the output waveform of the light receiving element and the output waveform of the distance sensor when the document of FIG. 16 is conveyed.

FIG. 18 is a block diagram showing a circuit configuration of a sixth embodiment of the present invention.

FIG. 19 is a block diagram showing a circuit configuration of a seventh embodiment of the present invention.

20 is a waveform diagram showing a waveform of an output signal of the circuit of FIG.

FIG. 21 is a block diagram showing another circuit configuration example of the seventh embodiment of the present invention.

FIG. 22 is a sectional view showing the arrangement configuration of the code reading device according to the eighth embodiment of the present invention.

[Explanation of symbols]

1, 2, 3, 4 Conveying roller 5 Reflective sensor 6 Amplifier 7 A / D converter 8, 11-13 Original 9 Code 10, 110 Conveying path 14, 15, 18, 22, 23, 26 Output waveform 16, 17, 19, 24, 25, 27 Slice level 20, 21, 131, 132 Curl original 112, 122, 123, 133 Output waveform 113-115, 124-126, 134, 135 Slice level 116-121, 127-130 Code change points 201-204, 251,252 Conveying rollers 205,206 Guide plate 207 LED 208 Lens 209 Light receiving element 210 Distance sensor 211,212 Original 213 Code 214,217 Output waveform 215,218 Slice level 220 Comparator 221,245 CPU

Claims (5)

[Claims] 1. A transport system for transporting a document, an optical sensor for optically detecting a code of a black-and-white pattern on the transported document, and a digital conversion for converting output data of the optical sensor into digital multi-valued data. Means for binarizing the digital multi-valued data output from the digital converting means by a large number of slice levels, and determining whether the length of the black or white portion in the binarized data is within a predetermined prescribed range. A code reading device, comprising: a binarizing unit that determines whether or not, and outputs only binary data of an affirmative determination as detection code data. 2. A transport system for transporting a document, an optical sensor for optically detecting a code of a black-and-white pattern on the transported document, and a digital conversion for converting output data of the optical sensor into digital multi-valued data. Means and the digital multi-valued data output from the digital converting means is binarized by deciding the length of the black and white part at the change point of the black and white part when binarizing the digital multivalued data by a plurality of slice levels,
A code reading device comprising: a code output means for selecting one of the digitized data and outputting it as code data representing black and white. 3. A curvilinear slice level having a correction according to the curl of the original document or the flapping of the original document, at least one of the plurality of slice levels. The code reader according to item 2. 4. When the values of the plurality of slice levels are not reversed from each other, the binary data which is sandwiched by the plurality of slice levels of the binary data for which the positive determination is obtained and which cannot be obtained for the positive determination is obtained. 3. The code reading device according to claim 1, further comprising a determination unit that determines a failure when the slice level exists. 5. A carrying system for carrying a document, an optical sensor for optically detecting a code of a black and white pattern on the carried document, and a distance sensor for measuring a distance between the optical sensor and the document. A code reading device comprising: a binarizing unit that binarizes output data of the optical sensor with a slice level corrected by output data of the distance sensor.