JPH11316794A - Method for reading and deciding segment information - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a segment information reading and deciding method which makes it possible to read segment information even if a recording plate, etc., where codes are recorded is dipped and stained or if lighting changes. SOLUTION: A code to be picked up as an image, the positions of segments which possibly constitute the picket-up image on the image are calculated, and differences in mean luminance between a small circle SS and a large circle BS are calculated at the positions of the respective segments on the image, the luminance differences at the positions of the calculated respective segment are compared with prescribed decision reference luminance difference; and when the luminance differences at the respective segment positions are larger than a decision reference luminance difference, it is decided that the segments 71 constituting the code at the positions of the segments are actually present and the code 7b of the image to be read which is picked up is decided on the basis of the decision result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of reading segment information by reading codes such as segmented characters and symbols by image processing. The present invention relates to a segment information reading determination method that enables reading even in a state of being stained by dust or the like, being deteriorated by illumination, or affected by natural light.

[0002]

2. Description of the Related Art Conventionally, for example, at a production site, in order to manage the history of parts, a control number or the like corresponding to the part is assigned to a pallet or the like on which the part is mounted. The number is read as a barcode or the like, the management information of the part stored in the computer or the like is read in correspondence with the management number, and the production management of the part is performed based on the management information.

[0003]

However, when a metal part is subjected to heat treatment such as carburizing, it is necessary to pass a pallet or the like through a heat treatment furnace. In many cases, the color changes to black and reading becomes difficult.

In order to avoid such a problem, a method of removing the plate from the pallet before and after the heat treatment to prevent the plate from being stained by carburizing or the like has been taken. In order to mount the corresponding plate on the pallet without error, a lot of trouble such as confirmation of the contents of the pallet is required, resulting in an increase in the number of manufacturing steps.

[0005] In view of the above circumstances, the present invention is intended for reading even when a recording plate or the like on which a code is recorded is stained by carburizing, heat, oil, mud, dust, or the like, or is deteriorated by illumination or affected by natural light. It is an object of the present invention to provide a segment information reading / judging method that makes it possible.

[0006]

According to the first aspect of the present invention, a code to be read (7b) is photographed as an image (GZ), and the photographed code (7b) is divided into a plurality of segments (7c). ), The position (S1, S2, S3, S4, S5, S6, S7) of each segment that can constitute the code on the image is calculated for each of the codes. At the position on the image of each segment that can constitute each code, its center (SS)
And calculating a luminance difference (DF) between the segment and a peripheral portion (BS) of a predetermined range around the central portion, and comparing the calculated luminance difference at the position of each segment with a predetermined judgment reference luminance difference (DF1). In the case where the luminance difference at each segment position is larger than the determination reference luminance difference, it was determined that the segment constituting the code actually exists at the position of the segment, and the image was captured based on the determination result. A segment information reading determination method is provided for determining the sign of an image to be read.

According to a second aspect of the present invention, the determination reference brightness difference is obtained by creating a dendrogram (DG) by a cluster analysis method based on the calculated brightness difference of the position of each segment. The segment information reading determination method according to claim 1, wherein the value is a value (CV) calculated as a cluster analysis determination value using a bisecting point of the luminance difference immediately before the gram is united (see FIG. 14).

According to a third aspect of the present invention, when comparing the luminance difference at the position of each segment with the judgment reference luminance difference, the judgment reference luminance difference (DF
2. The method according to claim 1, wherein the determination is performed by varying (1).
Or the segment information reading determination method described in 2 (see FIG. 12).

According to a fourth aspect of the present invention, when a dendrogram is created, dummy data (DD) is preset as an initial value at a luminance difference coordinate position indicating that there is no segment at a segment position. According to a second aspect of the present invention, there is provided a segment information reading determination method.

According to a fifth aspect of the present invention, the luminance difference value of the dummy data is two standard deviations of the average value of the luminance difference at the segment position where there is no segment.
5. The segment information reading / judging method according to claim 2, wherein a value shifted to the side where the segment exists by twice is used.

According to a sixth aspect of the present invention, a brightness detection window (26) comprising a small frame (SS) and a large frame (BS) provided so as to surround the small frame is set on the image. 6. The luminance difference is calculated based on a difference between the luminance in the small frame and the average luminance of an annular portion between the small frame and the large frame in the luminance detection window set above. (See FIG. 10).

According to a seventh aspect of the present invention, the brightness detection window includes a concentric small circle (SS) and a large circle (LS).
7. The segment information reading determination method according to claim 6, wherein

According to an eighth aspect of the present invention, when a plurality of codes are read and determined, a check code based on a combination of the plurality of codes is added to the plurality of codes to be read and the codes are read. At the time of judgment,
For each code determined to be read, the possibility of reading as a code other than the determined code is determined, and the code having the possibility is stored in a memory as a spare code, and the code of the image determined to be read is determined. The accuracy is checked based on the check code given to the combination of the codes, and as a result, a spare code is substituted for the corresponding code with respect to the combination of the codes determined to be incorrectly read, and the same 8. The segment information reading determination method according to claim 1, wherein a check is performed, and as a result, when it is determined that the spare code is correctly read, the spare code is determined to be a correct code. is there.

According to a ninth aspect of the present invention, the code to be read is a code constituted by a plurality of segment holes (7e) formed in the plate-like member (7). This is in the segment information reading determination method described in item 1 (see FIG. 3).

According to a tenth aspect of the present invention, there is provided the segment information reading determination method according to the ninth aspect, wherein the code is a numeral (see FIG. 4).

According to an eleventh aspect of the present invention, the code to be read is a numeral constituted by a plurality of segment holes (7e) formed in a plate-like member mounted on a pallet to be heat-treated. In the segment information reading determination method described in the section.

The numbers in parentheses are for convenience indicating corresponding elements in the drawings.
This description is not limited to the description on the drawings.
The same applies to the following [action].

[Operation] With the above configuration, the present invention provides:
The presence or absence of each segment constituting the code is determined based on the luminance difference.

At this time, the use of a uniform judgment reference luminance difference can be eliminated by using the cluster analysis technique.

Further, the presence or absence of each segment is appropriately determined according to the image state of the code by changing the determination reference luminance difference.

With the dummy data, it is possible to easily cope with the case where the segments exist at all the segment positions.

By storing the spare code, it is possible to estimate a correct code even for a code determined as a reading error as a result of the check by the check code.

[0023]

According to the first aspect of the present invention, when judging whether or not a segment is actually present at the position of the segment, the use of the luminance difference makes it possible to remove dirt around the code to be read, Or, the presence or absence of a segment can be determined more accurately than in the case of the absolute value luminance, which is likely to be influenced by the brightness of the image due to the deterioration of lighting or natural light, and the recording board etc. with the code recorded It is possible to read even in a state of being stained by carburization, heat, mud, dust, or the like, or in a state where lighting conditions have changed.

According to the second aspect of the present invention, since the cluster analysis judgment value (CV) can be set by using a statistical technique called cluster analysis, the judgment reference luminance difference floats and cannot be predicted in the future. It is possible to automatically and flexibly respond to a change in illuminance, contamination of the recording plate, and the like, thereby contributing to an improvement in the reliability of the determination.

According to the third aspect of the present invention, the presence or absence of a segment can be determined in a finely corresponding manner to the image state of each code by changing the determination reference luminance difference. Even when the plate or the like is contaminated, it is possible to make a judgment by changing the judgment reference luminance difference in conformity with such a contaminated state, and it is possible to make a highly reliable judgment.

According to the fourth aspect of the present invention, it is possible to appropriately utilize the cluster analysis method even when there are segments at all segment positions by the dummy data (DD).

According to the fifth aspect of the present invention, by setting the dummy data in this manner, it becomes possible to set the cluster analysis determination value (CV) to an appropriate value,
It has been experimentally confirmed that the existence of a segment can be determined very efficiently.

According to the sixth and seventh aspects of the present invention, the small frame (small circle) captures the segment and the annular portion surrounding the segment captures the portion around the segment by the luminance detection window (26). It is possible to effectively supplement the difference in the average luminance between the inside and outside of the segment.

According to the present invention, even if a reading error occurs due to the check code, the correct code can be estimated by substituting the spare code, and the reading reliability can be improved.

According to the ninth and tenth aspects of the present invention, it is possible to appropriately read a code such as a number drilled in a plate-like member, and a code such as a number formed of the segment can be read by a human. It is possible and management becomes easy.

According to the eleventh aspect of the present invention, even in a production site where the sign of heat treatment or the like is liable to be stained, the numbers can be read properly, and the plate member can be detached before and after the heat treatment. This eliminates the need to perform the work of confirming the pallet contents and the like, which is effective in reducing the number of manufacturing steps.

[0032]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a conveyor transport line 2 to which an example of the segment information reading determination device 1 is applied. The conveyor transport line 2 has a belt conveyor 5 installed along a predetermined transport line. The pallet 3 is mounted on the belt conveyor 5 in such a manner that the pallet 3 can be transported by the belt conveyor 5 in a predetermined transport direction, and the components 6 are mounted on the pallet 3. A management license plate 7 is removably mounted on the side surface of the pallet 3 via a bracket 3a and mounting bolts and nuts 3b. The management license plate 7 is mounted on the pallet 3 as shown in FIG. Part 6
Is formed in the form of being drilled in the management number plate 7. Each number 7b constituting the management number 7a is, as shown in FIG.
It is composed of a known combination of seven segments 7c. The management number plate 7 has two reading reference holes 7d in addition to the management number 7a.
Are provided at predetermined intervals.

As shown in FIG. 1, a segment information reading / judging device 1 is provided at an appropriate position in the middle of the conveyor conveying line 2. The management number 7a formed on the management number plate 7 attached to the pallet 3 conveyed on the conveyor 5 can be read and output to an appropriate production management device.

The segment information reading / judging device 1 is connected to the frame 5b of the belt conveyor 5 via the bracket 5a.
The CCD camera 9 is connected to the main body 1a of the reading determination device 1. The main body 1a has a main control unit 10 as shown in FIG.
Apart from the image processing unit 11, the luminance value calculation unit 12, the segment luminance difference analysis determination unit 13, the luminance difference analysis correction unit 15, the cluster analysis determination unit 16, the digit information determination unit 17, and the main unit 1a to which the D camera 9 is connected. The input unit 19, the output unit 20, and the display unit 21 such as a CRT are connected to each other.
The controller 22 is connected to the output unit 20. Reference numeral 23 in FIG. 1 denotes an illumination device provided on the frame 5b of the belt conveyor 5 for photographing by the CCD camera 9.

Since the segment information reading / judging device 1 and the like have the above-described configuration, the management information plate 7 attached to the pallet 3 conveyed on the belt conveyor 5 is read, and the components mounted on the pallet 3 are read. 6 is performed, the segment information reading determination device 1 reads the processing program shown in FIG. 5 stored in an appropriate memory (not shown), and performs a reading determination operation of the segment information based on the program. go.

First, the main control unit 10 instructs the CCD camera 9 to read the management license plate 7 mounted on each pallet 3 conveyed by the belt conveyor 5. In response to this, the CCD camera 9 captures the image of the management license plate 7 attached to the pallet 3 conveyed on the belt conveyor 5, and uses the captured image as image information VIF in the image processing unit 11 of FIG. Output to

When the image information VIF is input to the image processing unit 11, the main control unit 10 enters step S1 of the processing program, and sends the image information VIF to the image processing unit 11.
Based on F, a command is issued to read the reading reference holes 7d on both sides, which are necessary for analyzing the management number 7a on the management number plate 7, as shown in FIG. The image processing unit 7 receives this, and as shown in FIG. 10, the detection window 2 composed of concentric small circles SS and great circles BS.
6 is moved over the pixel within the square frame 25c set in the vicinity of the reading reference hole 7d in FIG. 7, and the average value of the luminance values of the pixels within the small circle SS and the distance between the small circle SS and the great circle BS are set. The average value of the luminance values of the pixels in the donut-shaped portion is compared, the position where the difference is the largest is detected, and the portion is determined as the reading reference hole 7d.

That is, each pixel constituting the image captured by the CCD camera 9 is classified into 256 levels of luminance values according to the brightness of the surface of the management license plate 7, as shown in FIG. It has luminance value information. Therefore, the pixel corresponding to the reference hole 7d formed in the management license plate 7 usually has the lowest lightness, that is, the lowest luminance value as compared with other stains and the like. Then, the detection window 26 is scanned within the rectangular frame 25c, and the average value of the luminance values of the pixels in the small circle SS and the average value of the luminance values of the pixels in the donut-shaped portion between the small circle SS and the great circle BS are set. Are compared, the position where the difference is the largest is detected, and the coordinate position of the central pixel of the small circle SS at that time is read and determined as the position of the reference hole 7d.

Thus, the reading reference holes 7d, 7
When the position of d on the image GZ is determined and calculated, the process proceeds to step S2, and the main control unit 10 reads the inclination θ of the plate 7 and the two readings on both sides as shown in FIG. Length BLA on image between reference holes 7d, 7d
Is calculated.

That is, as shown in FIG. 6, the five numerals 7b constituting the management number 7a on the management number plate 7 indicate that the reading reference hole 7d on the left side in the figure is the reference position P0. From the reading reference holes 7 on both sides
a predetermined reference distance XP in the direction of the line segment LS connecting
Positions S1, S2 of seven segments 7c formed on the basis of reference positions P1, P2, P3, P4, P5 set at positions separated by 1, XP2, XP3, XP4, XP5 and constituting each numeral 7b , S3, S4, S5, S6,
S7 is based on the corresponding reference positions P1 to P5.
As shown in FIG. 6, it is set in advance at a predetermined position.

Accordingly, in order to identify the position of the numeral 7b of each management number 7 and the position of each segment 7c constituting each numeral b from the image of the management number plate 7 captured by the CCD camera 9, FIG. As shown, the length BLA (actually, the number of pixels) on the image between the reading reference holes 7d on both sides of the captured image GZ is calculated, and the reading reference holes 7d on both sides are connected. The inclination angle θ of the line segment LS on the image is calculated, and the image is rotated by the angle θ to correct the horizontal state. Next, the reference points 7d on both sides,
The length BLA on the image between 7d, the actual length BL between the reference points 7d, 7d on both sides, which are known values, and the reference position P0 of each of the reference positions P1, P2, P3, P4, P5 Actual reference distances XP1, XP2, XP3, XP4, XP5
From the reference position P0 on the image to the respective reference positions P1, P
Reference distance XP1 on the image up to 2, P3, P4, P5
A, XP2A, XP3A, XP4A, XP5A are calculated. This can be easily calculated from the ratio of the length BLA on the image to the actual length BL.

Next, at step S4, the positions S1, S2, S of the seven segments 7c of each numeral 7b on the image are set.
3, S4, S5, S6, S7, that is, the read coordinate position of each segment 7c is calculated by the same method as when each reference position is calculated. When the read coordinate positions of all the segments 7 of each numeral 7b are determined on the image in this way, the main control unit 10 enters step S5 in FIG. The luminance measurement of the seven segments 7c is performed.

As shown in FIG. 10, the luminance of each segment 7c is measured by reading coordinate positions S1, S2, S of each segment 7c of each numeral 7b calculated in step S4.
3, a brightness detection window 26 including a small circle SS and a great circle BS formed concentrically is set in S4, S5, S6, and S7, and the brightness of each pixel in the small circle SS of the brightness detection window 26 is set. And the average value LV2 of the brightness of the donut-shaped annular portion 26a sandwiched between the small circle SS and the great circle BS. In this case, each read coordinate position S1, S2, S3, S4, S5, S6, S7 of each segment 7c.
When the segment hole 7e is not drilled,
In the case of the coordinate positions S1 and S7 in FIG. 10, the luminance difference DF between the average value LV1 of each pixel of the small circle SS and the average value LV2 of the luminance of the donut-shaped ring portion 26a is within the great circle BS. Since no holes or the like are drilled, it does not become so large. However, a slight difference in brightness DF occurs due to soot attached to the plate 7 or dirt such as oil. On the other hand, each read coordinate position S of each segment 7c
In the case where segment holes 7e are formed in 1, S2, S3, S4, S5, S6, and S7, that is, in the case of the coordinate positions S2 to S6 in FIG. Since the segment hole 7e is displayed as a black shadow on the image, the average value LV1 is significantly reduced as compared with a case where the segment hole 7e is not drilled. The donut-shaped annular portion 26a has a segment hole 7 partially dark.
However, most of the brightness is applied to the brighter plate surface portion, and the average value LV2 of the brightness does not decrease so much as compared with the case where the segment hole 7e is not formed. Therefore, the luminance difference DF at that time is larger than when the segment hole 7e is not formed.

Now, suppose that each coordinate position S1, S2, S3,
In S4, S5, S6, and S7, when the presence or absence of the segment hole 7e at each coordinate position is determined based on the absolute value of the brightness of the brightness detection window 26, as shown in FIG. Approximately 3.6% of the wrap area occurs without holes. In this case, as in the case of the present embodiment,
When the number to be determined is a five-digit number, a large variation occurs in the brightness value of each coordinate position, and accurate reading becomes impossible. Therefore, the main control unit 10 causes the luminance value calculation unit 12 to measure and calculate the luminance of each coordinate position of each reference position in step S5. When the luminance at the position is measured by the luminance detection window 26, the average value of the luminance of the donut-shaped annular portion 26a between the small circle SS and the great circle BS from the average value LV2 to the average value of the luminance of the small circle SS portion The difference obtained by subtracting LV1 is obtained as a luminance difference DF, and a command is issued to determine the presence or absence of the segment hole 7e based on the luminance difference DF.

That is, the segment luminance difference analysis determination section 13
Are coordinate positions S1, S2, S3, S4, S5, S6,
Regarding S7, the luminance difference DF is calculated, and when the luminance difference DF is equal to or more than a predetermined value (for example, 15), it is determined that the segment position 7e is present at the coordinate position, and the luminance difference DF is equal to or less than the predetermined value. In this case, it is determined that there is no segment hole 7e at the coordinate position. As described above, the segment hole 7e is determined based on the luminance difference DF between the annular portion 26a and the small circle SS.
As shown in FIG. 11, it can be determined very clearly whether there is a black circle and no white circle, and the wrap area is only 0.33%, as shown in FIG. In this case, in the case of a five-digit number as in the present embodiment, the reading rate is calculated as 89% (1-5 [digits] × 7 [segments] × (0.33 / 10
0) × 100 [%]). Thus, in the segment luminance difference analysis determination unit 13, the coordinate positions S1, S5 of the reference positions P1, P2, P3, P4, P5 of each numeral 7b.
By determining the presence or absence of the segment hole 7e for 2, S3, S4, S5, S6, and S7, the number 7b drilled at each reference position can be accurately determined with high probability.

However, when the judgment is made based on the luminance difference DF, as shown in FIG. 12, for example, the judgment reference luminance difference DF1 as the judgment reference value indicating that there is the segment hole 7e is set to 15
, The respective coordinate positions S1, S2, S3, S of the respective numerals 7b
When the luminance difference is determined for S4, S5, S6, and S7, a situation may occur in which it cannot be determined as a number, as shown in FIG. In this case, the main control unit 1
A value of 0 causes the luminance difference analysis and correction unit 15 to slide the luminance difference determination reference value to make the determination.

That is, in the case of FIG. 12, for example, as shown in the sample example of (a), each coordinate position S1, S2, S3, S3
When the brightness difference DF is calculated for each of S4, S5, S6, and S7 as shown in FIG. 7B, the brightness difference DF1, which is a reference for determining that there is a segment hole, is set to 15, the coordinate position S3, Only S4 and S5 are determined to have segment holes. However, since only the segment holes 7e at the coordinate positions S3, S4, and S5 do not constitute meaningful numerical information, the luminance difference analysis and correction unit 15 determines the determination reference luminance difference DF1 as a reference up to that point. The value is changed from 15 to 10 having the next smallest luminance difference. Then, as shown in the center of FIG. 11C, it is determined that there is a segment hole also at the position S2 where the luminance difference DF was 10, but still does not constitute meaningful numerical information. Therefore, the luminance difference analysis and correction unit 15 further changes the determination reference luminance difference DF1, which is the reference for the previous determination, from 10 up to that point to −2, the next smaller luminance difference. Then, FIG.
At the position S6 where the luminance difference DF was -2,
Is determined to have a segment hole, and as a result, it is determined that there is a segment hole 7e at the coordinate positions S2, S3, S4, S5, and S6.
Is determined. As shown in FIG. 4, only the numbers from 0 to 9 are used as the numbers 7b of the management numbers 7a. Thus, the presence or absence of the segment holes 7e corresponding to the numbers 0 to 9 is determined. By gradually lowering the criterion luminance difference DF1 until a point at which the segment hole 7e can be determined, it is possible to accurately determine the position of the segment hole 7e even at a coordinate position that is not determined to have a segment hole in the normal criterion luminance difference DF1. By determining the presence or absence, it is possible to quickly and accurately determine each numeral 7b of the management number 7a.

However, even if such correction does not make it possible to determine the presence or absence of the segment hole 7e and cannot determine each of the numbers 7b of the management number 7a, step S7 in FIG.
The main control unit 10 instructs the cluster analysis determination unit 16 to determine the presence or absence of a segment hole by cluster analysis.

That is, as shown in FIG. 13, the second numeral “4” from the left side of the figure on the management license plate 7
b, each coordinate position S1, S
2, S3, S4, S5, S6, S7, the luminance difference D
F is S1 = 81, S2 = -13, S3 = -11, S4
= 84, S5 = 21, S6 = 91, S7 = 64, and if the determination reference luminance difference DF1 is set to 15, the coordinate positions S1, S4, S5, S6, and S7 are determined to have a segment hole, and "4" cannot be recognized. In this case, the criterion luminance difference DF is lowered to -11.
When it is determined that the coordinate position S3 has a segment hole,
The number "9" is recognized, but in this case, the determination reference luminance difference DF1 is reduced until it is determined that there is a segment hole that is determined as meaningful numerical information at each coordinate position. And reliability issues.

Therefore, as shown in FIG. 14, the cluster analysis judging section 16 obtains a cluster analysis judgment value CV for judging the presence or absence of the segment hole 7e by using a cluster analysis method based on the shortest distance method. Now, suppose that Figure 1
As shown in FIG. 4, dirt 7f adheres to a portion corresponding to the coordinate position S4 of the numeral 7b, and the coordinate positions S1, S2, S
When the luminance difference DF of 3, S4, S5, S6, and S7 is calculated as shown in the table of FIG. 14, a dendrogram (tree diagram) DG is created and calculated by the cluster analysis method. In this case, assuming that the segment holes 7e are present at all the coordinate positions, such as when the number 7b is “8”,
The dummy data DD is set in advance at an appropriate luminance difference DF position as an initial value. As the luminance difference position of the dummy data DD, a value obtained by shifting the average value in a set of luminance differences DF of a large number of coordinate positions when there is no segment hole toward the side with the segment hole by twice the standard deviation thereof is adopted. Then, an experiment by the inventor has found that an appropriate cluster analysis determination value CV can be set, and the subsequent determination can be performed extremely effectively.

The cluster analysis judging unit 16 calculates the dendrogram D from the luminance difference DF at each coordinate position by the shortest distance method.
G is created, and the bisection point of the distance (luminance difference) immediately before the dendrogram DG is united into one is defined as the cluster analysis determination value CV, and the luminance at the seven coordinate positions of each numeral 7b is calculated based on the analysis determination value CV. The difference DF is determined, and the presence or absence of the segment hole 7e is determined. That is, the portion S4 in FIG. 14 is determined to have no segment hole, and the numeral 7b is determined to be “0”.

Now, assuming that the luminance difference data as shown in FIG. 13 is obtained for the 21 numerals 7b of samples 1 to 21, if the determination reference luminance difference DF1 is set to 15, The coordinate positions without segment holes indicated by white circles of 13, 15, 18, and 21 are determined to have segment holes, and the management number 7a cannot be accurately determined (sample 5 has already been described as a plot example. is there). Therefore, a cluster analysis determination value C is obtained for each such sample by cluster analysis.
V is determined, and the segment hole 7 is determined based on the analysis determination value CV.
When the presence / absence of e is determined, as shown in FIG. 15, the presence / absence of the segment hole 7e indicated by a black circle and the absence of the segment hole 7e indicated by a white circle are appropriately determined for samples other than the samples 11, 17, 18, and 19. Was completed. Therefore, FIG.
In the case of the sample 5 shown in FIG. 15, the presence or absence of the segment hole 7e is appropriately determined as shown in FIG.
Is not determined to have a segment hole, and is accurately determined to be “4”.

Thus, the segment holes 7 constituting the respective management numbers 7a with respect to the respective reference positions on the management plate 7
When the presence or absence of e is determined, the main control unit 10 returns to FIG.
Step S8 is performed, and the five-digit numerical value on the management plate 7 is determined by integrating the determination operations of Steps S6 to S7.

In the above description, the determination of the presence / absence of a segment hole is described as a fixed reference value such as a luminance difference FD1 of 15, for example. And it is preferable to set a floating value based on the above-described cluster analysis judgment from the beginning. That is, as described above, in the fixed reference value determination, which group of the population belongs to which group, a lap of about 0.33 [%] occurs with respect to the presence or absence of a hole, and a misjudgment as a numeric string occurs. Another possibility is high, but using the above-described cluster analysis that discriminates the seven segment group that constitutes one number into two with or without holes, and floating the judgment reference value according to the image state at that time , The probability of erroneous determination is greatly reduced.

Then, the presence or absence of a segment hole is determined based on the reference value for determining the presence or absence of a hole by the cluster analysis, and as a means for supplementing the segment hole, the above-described automatic slide of the determination value to make it meaningful as numerical information (luminance) The difference analysis correction unit) and the inverse estimation (digit information determination unit) based on digit information described below further reduce the probability of erroneous determination. By floating the judgment reference value based on the cluster analysis, it is possible to automatically and flexibly cope with unpredictable changes in illuminance, oil spots on the plate, and blackening due to heat treatment. In particular, according to the cluster analysis, it is extremely unlikely that a portion without a segment hole is determined to be present. As a result, the erroneous determination as described in FIG. 13 can be eliminated, and the determination by the luminance difference analysis correction unit can be performed. The automatic sliding of the value and the reverse estimation (described later) by the digit information determination unit function effectively.

Next, the main controller 10 enters step S9, and determines whether each management number 7a can be read as another numerical value. That is, the number “1” is “7”, “8”, or “4” depending on whether or not the segment hole 7e is determined.
It can be read as "0". Therefore, in steps S6 to S7 described above, if there is a readable numerical value when the judgment reference luminance difference DF1 is further reduced, the numerical value is read. If the numerical value is properly read in step S6, the cluster analysis is performed in step S7. Then, if there is a possibility of another reading method, etc., the numerical value is replaced with each numeral 7b.
Is stored in an appropriate memory in a form corresponding to.

Next, the main control unit 10 executes step S1 in FIG.
Entering 0, the digit information determination unit 17 checks whether the five-digit number 7b determined as the five-digit management number 7a on the management license plate 7 in step S8 is a known check digit or not. It is determined by calculation. In the five-digit management number 7a on the management number plate 7, the first four digits are the tray number necessary for managing the pallet 3, and the last one digit is the first four-digit tray number. This is a check digit for determining whether or not it has been read.

Since this check digit calculation is a known method, a detailed description thereof will be omitted here. In this embodiment, however, the modulus 10/3 weight used in bar codes JAN, ITF, NW7, etc. We adopted a technique called. According to this method, for example, if the 4-digit tray number is “2407”, the check digit is “5”, and the 5-digit management number 7a is “2407”.
5 ". Therefore, the digit information determination unit 17 checks from the five-digit management number 7a determined to be read whether or not the management number 7a has been read without error by check digit calculation.

That is, the read five-digit management number 7
If “a” is determined to be “24075” in step S8, the check digit is calculated as “5” by the check digit calculation of the first five digits “2407”, and the fifth digit “5” of the management number 7a is determined. , It is determined that the management number 7a has been correctly read.
In this case, via steps S11 to S12 and S13,
An erroneous reading check and a plate number check are performed to determine whether or not the numerical value read as the actual management number exists as the management number 7a, and whether or not the numerical value is currently flowing on the belt conveyor 5 even if it exists, at step S14. Displays the 5-digit management number 7a on the display unit 21 such as a display, and outputs the output unit 2 at step S15.
The information is output to an appropriate controller such as a sequencer through the control unit 0, and processing corresponding to the component 6 mounted on the pallet 3 is performed.

On the other hand, if the five-digit management number 7a is determined to be "24115" in step S8, the digit information determination unit 17 calculates the first five-digit "2411" check digit in step S10. , The check digit is required to be “8”. Then, since it does not match the fifth digit “5” of the management number 7a, the digit information management unit 17 determines that the management number 7a has not been correctly read, and proceeds from step S11 to step S16. At S9, the numerical value determined to be possibly read as another numerical value is substituted for the numerical value 7b of each management number 7a, and the same check digit calculation is performed to determine whether the check digit is established. Then, an operation of estimating the correct management number 7a is performed.

That is, the digit information determination section 17 determines in step S9 that there is a possibility that it can be read as another numerical value, and for the numerical value stored in a predetermined memory, for example, the third digit 7b, As for “7”, “0”, and the fourth digit 7b, read “7”, substitute them for the digit 7b of each digit, perform check digit calculation, and determine whether the check digit is established. Is determined. In this case, the first 4-digit tray number is “2417”
In the case of, the check digit becomes “6” and “247”
In the case of “7”, the check digit becomes “2” and “24”
71, the check digit becomes “4” and “2”
407 ", the check digit is" 5 ",
In the case of “2401”, the check digit becomes “7” and the check digit in the fifth digit matches “24”.
07 ”. Therefore, the process proceeds to step S17, and if there is only one 5-digit management number 7a having the same check digit as the above estimation operation, the number is adopted as the read management number 7a, and steps S12 and S13 are performed. , The 5-digit management number 7a is displayed on the display unit 21 such as a display in steps S14 and S15, and the information is output to an appropriate controller such as a sequencer via the output unit 20, and the pallet 3 Processing corresponding to the component 6 mounted thereon is performed.

As a result of the numerical estimation in step S16,
If two or more 5-digit management numbers 7a for which a check digit is established are estimated, a reading error is generated.
From step S17 to step S18 through step S18
1, the reading operation for the management license plate 7 is performed again. At this time, the square window 25 set when reading the reading reference holes 7d, 7d in step S19.
Change the position, size, etc. of c and read the reference hole 7 accurately.
d and 7d can be read. In this embodiment, the rereading operation for the management license plate 7 is performed up to four times.

In the embodiment described above, the codes to be read by the segment information reading determination device 1 are as follows:
In the case of the management number 7a consisting of the number 7b formed by forming a segment hole 7e in the management number plate 7, the code to be read is formed as a segment hole as long as it is a segmented code. Even if it is not provided, it may be written on a board with paint or the like.
Further, the code is not limited to a numeral, but may be a character such as an alphabet, a character such as katakana or hiragana, a kanji, or another symbol. Furthermore, even if the code to be read is not displayed in a segmented form, the image may be electronically divided and appropriately segmented after the code is captured by a capturing means such as a CCD camera. Good.

Further, the present invention is not limited to the case of reading the management number 7a of the management number plate 7 mounted on the pallet 3 conveyed on the belt conveyor as in the above-described embodiment. When reading, or a recording plate or the like on which a code is recorded
The present invention can be suitably applied to a case where it is necessary to read even in a state where the sheet is contaminated by dust or the like.

The positions S1, S2, S
The configuration of the luminance detection window 26 for measuring the luminance difference DF of 3, S4, S5, S6, and S7 does not need to be constituted by concentric small circles SS and large circles BS as shown in FIG. In a form corresponding to the shape of the hole 7e, the hole 7e can be constituted by an arbitrary shape and size of a central portion and a peripheral portion of a predetermined range around the central portion.

[Brief description of the drawings]

FIG. 1 is a diagram showing a conveyor transport line provided with an example of a segment information reading device.

FIG. 2 is a control block diagram illustrating an example of a segment information reading device.

FIG. 3 is a diagram showing an example of a management license plate.

FIG. 4 is a diagram showing segmented numbers.

FIG. 5 is a diagram showing an example of a processing program executed by the segment information reading device.

FIG. 6 is a diagram showing positions of seven segments corresponding to respective reference positions on a management license plate.

FIG. 7 is a view showing an example of an image of a management license plate.

FIG. 8 is a diagram illustrating an example of a state of a luminance value of an image captured by a CCD camera.

FIG. 9 is a view showing an absolute value luminance distribution of a segment hole.

FIG. 10 is a diagram showing an example of a technique for measuring a luminance difference at each segment position.

FIG. 11 is a diagram showing a luminance difference level depending on the presence or absence of a segment hole.

FIG. 12 is a diagram illustrating a state in which the presence or absence of a segment hole is determined based on a determination reference luminance difference.

FIG. 13 is a diagram showing an example in which a determination is defective in a determination based on a determination reference luminance difference.

FIG. 14 is a diagram showing an example of a cluster analysis.

FIG. 15 is a diagram illustrating an example of determining the presence or absence of a segment hole based on a cluster analysis determination value obtained by cluster analysis.

[Explanation of symbols]

7 Plate-shaped member (management license plate) 7b Code (number) 7c Segment 7e Segment hole 26 Luminance detection window Position on image S1, S2, S3, S4, S5, S
6, S7 CV cluster analysis judgment value (judgment reference luminance difference) DD dummy data DF luminance difference DF1 judgment reference luminance difference DG dendrogram GZ image SS small frame (small circle) BS large frame (large circle)

Claims (11)

[Claims] An image of a code to be read is taken as an image, and the taken code is composed of a plurality of segments, and for each of the codes, on the image of each segment capable of constituting the code. At the position on the image of each segment that can constitute each of the calculated codes, calculates the luminance difference between the center and the periphery of a predetermined range around the center; The calculated luminance difference at each segment position is compared with a predetermined determination reference luminance difference. If the luminance difference at each segment position is larger than the determination reference luminance difference, the code is formed at the position of the segment. A segment information reading determination method which determines that a segment actually exists, and determines the sign of an image to be read based on the determination result. 2. A method according to claim 1, wherein the determination reference luminance difference is obtained by creating a dendrogram by a cluster analysis method based on the calculated luminance difference of each of the segments, and determining the luminance difference immediately before the dendrogram is united. 2. The segment information reading determination method according to claim 1, wherein the two-divided point is a value calculated as a cluster analysis determination value. 3. The method according to claim 2, wherein, when comparing the luminance difference at the position of each segment with the judgment reference luminance difference, the judgment is made by varying the judgment reference luminance difference according to each code on an image. 3. The segment information reading determination method according to 1 or 2. 4. The segment information reading determination according to claim 2, wherein when the dendrogram is created, dummy data is set in advance as an initial value at a luminance difference coordinate position indicating that there is no segment at the segment position. Method. 5. The luminance difference value of the dummy data is a value obtained by shifting the average value of the luminance difference at a segment position where there is no segment by twice the standard deviation to the direction where the segment exists. Item 5. The segment information reading determination method according to item 2 or 4. 6. A brightness detection window including a small frame and a large frame provided so as to surround the small frame is set on the image, and the brightness of the brightness detection window set on the image in the small frame is set. 6. The segment information reading determination method according to claim 1, wherein the luminance difference is calculated based on a difference between an average luminance of an annular portion between the small frame and the large frame. 7. The segment information reading determination method according to claim 6, wherein the luminance detection window is a small circle and a large circle formed concentrically. 8. When reading and determining a plurality of codes,
A check code based on a combination of the plurality of codes is added to the plurality of codes to be read, and when the codes are determined to be read, each of the codes determined to be read can be read as a code other than the determined code. And the likelihood of the code is stored in the memory as a spare code, and the accuracy of the code of the image determined to be read is checked based on the check code given to the combination of the codes. Then, as a result, the same check is performed by substituting the spare code into the corresponding code for the combination of codes determined to be incorrectly read, and as a result, when it is determined that the code is correctly read, 8. The segment information reading device according to claim 1, wherein the spare code is determined to be a correct code. Taking judgment method. 9. The segment information reading determination method according to claim 1, wherein the code to be read is a code formed by a plurality of segment holes formed in the plate member. 10. The segment information reading determination method according to claim 9, wherein said code is a numeral. 11. The segment information reading determination method according to claim 10, wherein the code to be read is a number constituted by a plurality of segment holes formed in a plate-like member mounted on a pallet to be heat-treated.