JPH05334481A - Method for recognizing pixel code - Google Patents

Abstract

PURPOSE:To prevent the generation of misrecognition by writing a reference mark added to a pixel code to indicate the position of the pixel code on an object. CONSTITUTION:Two reference marks 4, 5 are written on previously determined positions in a code area 6 having a fixed size. A dot image shown by black dots written in an area B constitutes an image pattern for a pixel code to be recognized. For instance, a pair of binary numbers, '0101' in this case, are shown by the existence of dots on four dot positions included in an-area A (each + code indicates a space). The parity of a bit pattern shown by a dot pattern is written on the light end part and lower end part of a code area 6 by a dot existence format. Thereby a dot pattern image can be read out on a normal position by adding the reference marks 4, 5 to a written pixel code, so that a dot pattern detecting position can be prevented from being detected in error due to a deviation in a position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recognizing a pixel code by reading a pixel code written on an object and converting a numerical value represented by the pixel code into a code signal.

[0002]

2. Description of the Related Art Conventionally, a barcode recognition method has been widely known as a code recognition method. The barcode recognition method is a method in which a plurality of bar-shaped figures are written on an object such as a label, the width of the bar figure is detected, and the bar code is converted into a code signal corresponding to the width.

However, since the bar code recognition method uses the width of the bar figure as a characteristic element, there is a drawback that the entire bar code becomes large. Therefore, a dot pattern type code expression called a pixel code has been attracting attention because the described code can be made small. The pixel code is a code that represents a bit value "1" or "0" depending on the presence or absence of a dot.

[0004]

However, when the pixel code is recognized by the code recognition device, if the reading position of the pixel code deviates from the normal reading position, erroneous recognition occurs and dust attached to the pixel code. There is still room for improvement in that the device cannot automatically detect the erroneous recognition due to stains or the like.

Further, when the pixel code is formed on the printed circuit board, the label sticking method has a problem in storability, and the marking method has a problem that an erroneous recognition easily occurs on the code recognition device side.

Therefore, in view of the above points, an object of the present invention is to provide a pixel code recognition method capable of preventing erroneous recognition.

[0007]

In order to achieve such an object, the invention of claim 1 picks up an image of a pixel code in the form of a dot pattern described on an object, and sets the dot pattern in the picked-up result to 2 dots. In the pixel code recognition method which outputs a numerical value indicated by the pixel code by digitizing, a reference mark indicating the position of the pixel code is added to the pixel code, and the reference mark is written on the object.

According to a second aspect of the present invention, in addition to the first aspect of the present invention, the amount of positional deviation between the first position of the reference mark in the image pickup result and the regular second position predetermined for the reference mark is calculated. It is characterized by detecting and correcting the position of the image pickup result based on the detected position shift amount.

According to a third aspect of the present invention, a pixel code in the form of a dot pattern described on an object is imaged, and the dot pattern in the imaged result is binarized to output the numerical value indicated by the pixel code as a signal. In the code recognition method, the line direction parity in the pixel code is added to the description of the pixel code in the form of the presence or absence of a dot, and the imaging result is obtained by using a bit value of the parity binarized from the imaging result. The parity check of the binarized bit value is performed for the dot pattern in the above.

In addition to the invention of claim 3, the invention of claim 4 is characterized in that the parity is added in the horizontal direction and the vertical direction of the pixel code.

According to a fifth aspect of the present invention, a pixel code in the form of a dot pattern described on an object is imaged, and the dot pattern in the imaged result is binarized to output the numerical value indicated by the pixel code as a signal. In the code recognition method, at least the outer surface of the portion of the object where the pixel code is described is formed of a first member having a low light reflectivity, and a second member having a high light reflectivity is provided inside the first member. Is provided so as to contact the first member, and the first member is burned off by laser irradiation to expose the second member, whereby the dot pattern of the pixel code is described.

According to a sixth aspect of the present invention, the numerical value indicated by the pixel code is corrected by partially masking the dot pattern of the pixel code described by the pixel code recognition method of the fifth aspect. ..

According to a seventh aspect of the invention, in the sixth aspect of the invention, all the dots which are located at the end of the dot pattern of the pixel code and which form the dot pattern of one row or one column are to be masked. Is characterized by changing the number of digits of the numerical value indicated by the pixel code.

According to an eighth aspect of the present invention, a pixel coded in the form of a dot pattern described on an object is imaged, and the dot pattern in the imaged result is binarized to output the numerical value indicated by the pixel code as a signal. In the code recognition method, the dot pattern is described by forming the outer surface of the object of the portion described in the pixel code with a member having light reflectivity lower than that of solder, and performing solder plating on the member. Is characterized by.

[0015]

According to the invention of claim 1, the position of the dot pattern in the image pickup result can be corrected by detecting the reference mark in the image pickup result. Further, it is possible to detect an error in which the dot pattern image exceeds the image pickup screen, and it is possible to prevent erroneous recognition of the pixel code.

According to the second aspect of the invention, since the position of the dot pattern image is corrected based on the reference mark, the pixel code will not be erroneously recognized even if the position of the object is displaced.

According to the third aspect of the invention, the occurrence of erroneous recognition of the parity code can be detected by the parity check of the pixel code.

According to the fourth aspect of the invention, even if a parity error occurs in one direction, it is possible to restore the error-checked data to normal data by using the parity check result in the other direction.

According to the fifth aspect of the invention, the contrast between the dot pattern portion and other portions becomes clear, and the binarization accuracy improves. Further, since the dot pattern is written by laser irradiation, the pixel code can be written on a small object such as a printed circuit board.

According to the sixth aspect of the present invention, the pixel code created by erroneous laser irradiation can be masked to correct it.

According to the invention of claim 7, a pixel code with a small number of digits is created by masking all dots at the end portions of the pixel code created by erroneous laser irradiation.

According to the eighth aspect of the present invention, for example, when a pixel code is written on a printed circuit board, the pixel code can be created, for example, in a solder plating manufacturing process of the printed circuit board itself without using a laser irradiation device. ..

[0023]

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

Prior to the description of the present invention, an image pattern for a pixel code used in this embodiment will be described.
An example of this image pattern is shown in FIG.

In FIG. 1, two reference dots (reference marks according to claim 1) 4 and 5 are described at predetermined positions in the code area 6 having a certain size. The dot image indicated by a black circle described in the area B constitutes a pixel code image pattern to be recognized. The + symbol in FIG. 1 is shown to indicate the dot position and is actually blank. In this embodiment, for example, a set of binary numbers is represented by the presence / absence of dots at four dot positions included in area A. In the example of the dot pattern in the area A, there is a dot in the second and fourth columns, so the numerical value represented by this dot pattern is expressed as a bit pattern in the code signal, which is "0101".
In decimal notation, it is "5" (0x2 ³ + 1x2 ² + 0x2 ¹
+1). In the present embodiment, a plurality of sets of such dot pattern images are two-dimensionally described in the area B, then the dot pattern images are read and converted into BCD (binarized decimal) code signals.

Further, in this embodiment, the parity for the bit pattern indicated by the dot pattern (the pattern in which bits "0" or "1" are combined) is expressed by the dot presence / absence form. The parity is a bit value indicating that the total of the bit patterns is an odd number or an even number. In this example, when the total number is an even number, it is "1", and when the total number is an odd number, it is "0".

In the example of FIG. 1, since there are three dots existing in the x direction of the first row in area B, the parity in the line direction has no dot at the dot position C of the first row and tenth column. It is represented by. Further, the parity check result for the first column in the y direction is shown in the 10th row and the 1st column without dots.

Similarly, the parities for other rows or columns in the x and y directions are described at the right end and the lower end of the code area 6.

The dot indicating such a parity is used for detecting erroneous recognition in the code recognition described later.

FIG. 2 shows a vertical cross-sectional structure of a printed circuit board on which a pixel code having such a dot pattern is formed.

In FIG. 2, 7 is a base material of a printed board, a copper foil 8 is fixed on the base material 7, and the surface of the copper foil 8 is a solder-plated solder film. Further, a resist protective film 9 is printed on the surface of the solder film.

FIG. 3 shows an enlarged structure of the center of the dot pattern portion 3 of FIG.

As in FIG. 2, 7 is a base material of the printed board, and 8
Is a copper foil, 9 is a resist protective film using a member that forms an outer surface and does not reflect external light, and 10 is a member that is located in a lower layer in contact with the resist protective film and reflects external light, for example, A solder film is shown. Each dot forming the dot pattern portion 3 shows a state in which the resist protective film 9 is burnt and peeled off in a spot pattern by laser irradiation by laser irradiation or the like, and the solder film 10 is exposed at 10 'portion due to burnout peeling. It is in a state of reflecting light. Therefore, a clear contrast is created with respect to the resist protective film 9 that does not reflect external light. The filled circles (black circles) in FIG. 1 indicate the solder film exposed portions 10 '.

An embodiment in which the identification code 14 according to the present invention is provided on the printed circuit board 13 is shown in FIG.

In FIG. 4, reference numeral 15 is a positioning hole for the printed circuit board 13. Further, 16 indicates the area length of the barcode when the BCD value represented by the recognition code 14 is represented by the barcode.

In the recognition code according to the present invention, since the diameter of the bit patterns can be set to about φ0.15 mm, the interval between the bit patterns can be set to 0.3 to 0.4 mm. Therefore, in the recognition code according to the present invention, the code area is about 4 mm □ in a 20-digit recognition code example, and the area length of a typical CODE 39, code bar, and interleaved 2055 bar code used for FA applications. About 1 of L '
/ 11 to 1/18. For reference, the relative ratios of the barcode area and the present invention are as follows.

CODE39 Approx. 75.3 mmL (corresponding to the code of the present invention is about 1 / 17.5) Code bar Approx. 59.7 mmL (corresponding to the code of the present invention is about 1
/14.9) Interleaved 2 of 5 Approx. 45.4 mmL (corresponding to the code of the present invention is approximately 1 / 10.6) By this, it becomes possible to newly provide an identification code on an object which does not have a space for providing an identification code in the past, and processing , It can make an epoch-making contribution to the rationalization of manufacturing and distribution management in the assembly field.

FIG. 5 shows a circuit configuration of a code recognition device for identifying the recognition code thus formed.

In FIG. 5, a CCD image pickup device 100 using a solid-state image pickup element (CCD) picks up an image of the entire pixel code shown in FIG. An analog / digital (A / D) converter 101 converts an analog image signal (luminance signal) output from the CCD image pickup device 100 for each pixel into a digital value. A dual port memory is used for the random access memory (RAM) 102, and the A / D converter 1
The digital image signal output from 01 is stored in association with the pixel position.

The central processing unit (CPU) 104 is
After the image signal for one screen is stored in the AM 102, the dot read position is corrected, the code represented by the read dot is recognized, and the presence or absence of erroneous recognition is checked based on this image signal.

A processing program (shown in FIG. 6) for the CPU 104 to execute such processing is stored in the read-only memory (ROM) 103. Also, CPU
The calculation data related to the calculation processing of 104 is temporarily stored in the RAM 105.

Next, the code recognition processing of this embodiment will be described with reference to FIG.

When the image signal for one screen is stored in the RAM 102, the CPU 104 detects the reference dot and its screen position from the allowable range described in the reference dot on the read screen. More specifically, an image signal group having a certain luminance value or less indicating a dot (black) is detected from the reference dot description range in the RAM 102,
The positions of the reference dots 4 and 5 in the screen are detected by calculating the average of the pixel positions of this image signal group (steps S10 → S20 in FIG. 6).

Next, the CPU 104 calculates the amount of positional deviation between the detection positions of the reference dots 4 and 5 and the predetermined regular position. More specifically, as shown in FIG. 7, the reference dot 4 is aligned with the detection position and the regular position, and then the positional deviation amount between the detection position of the detection reference dot 5 and the regular reference dot 5 ′ is calculated. (In this case, the angle) α'is calculated (step S30 in FIG. 6).

Next, the CPU 104 converts the storage position of each image data in the RAM 102 so as to correspond to the position rotated by the angle α'about the position of the reference dot 4 in FIG. Therefore, the positions of the dots before conversion shown by white circles in FIG. 7 are corrected to the read positions of the normal dots after conversion shown by black circles (step S40 in FIG. 6). After that, the image data of the area indicated by reference numeral 12 in FIG. 7 for each dot is used to determine the presence / absence of a dot.

After the position correction of the read image signal, the CPU 104 sets an area 12 centered on each dot position, reads the image signal of this area from the RAM 102, and performs binarization processing. The binarized binary data is stored in the RAM 105 in association with the dot position (steps S50 → S60 → S70 in FIG. 6).

After this, the CPU 104 samples the binary data in the area B (see FIG. 1) on the RAM 105 and converts it into the BCD value. More specifically, in FIG. 1, four binary data corresponding to the area A, that is, a group of bit values are sequentially taken out in a fixed direction to obtain a BCD.
Conversion to a value is performed (step S80 in FIG. 6). This BC
The D conversion value is temporarily stored in the RAM 105.

Next, the CPU 104 performs a parity check using the bit value of the parity position (corresponding to the code C in FIG. 1) of the RAM 105 and the bit value of the pixel code for one line in the x direction or the y direction. If there is no parity error, switch the line. If there is no error in all the parity checks in the x (horizontal) direction and the y (vertical) direction, the CPU 104 determines that the code recognition result is normal and outputs the BCD conversion value temporarily stored in the RAM 105 to an external device. (Step S90 → S10 in FIG. 6)
0 → S110).

On the other hand, if an error is detected in the parity check, the CPU 104 outputs an error signal indicating the occurrence of the error and its position to the external device (FIG. 6).
Steps S90 → S100 → S120).

Besides the present embodiment, the following examples can be given.

(1) In this embodiment, the pixel code representing the BCD value is shown in FIG. 1, but the numerical value given to the pixel code may be a simple binary code string.

(2) In this embodiment, the parity added to the pixel code is provided in each of the horizontal (x) direction and the vertical (y) direction, but it can be set in only one direction (claim 3). Equivalent to the invention). In this case, the size of the entire pixel code can be reduced, but when a parity error occurs, the correct pixel code cannot be restored based on the parity in the other direction as in the present embodiment.

(3) With respect to the positional deviation amount (angle α) of the pixel code detected in this embodiment, an allowable range in which the pixel code fits on the image pickup screen is determined, and an error signal is output even when the positional deviation amount exceeds the allowable range. It can also be generated. In this case, the CPU 104 compares the positional deviation amount with the allowable range.

(4) In the present embodiment, the shape of the dots used for the pixel code is a circle, but a square shape or various figures can be used. In addition, as the mark indicating the reference position, not only the dot as in this embodiment but also a mark such as a straight line can be used.

(5) In this embodiment, the area read by the CPU 104 from the RAM 102 (see FIG. 5) is fixed in order to detect the presence or absence of dots. To this end, the CCD 100
The storage position on the RAM 102 is corrected so that the captured image signal is located at the normal position. However, it goes without saying that the storage position of the captured image position may be fixed and the area to be read out for detecting the presence / absence of dots may be changed.

(6) By providing the parities in the horizontal and vertical directions as in this embodiment, it is possible to detect erroneous recognition due to the influence of noise and to perform correct recognition again. For example, if a parity error occurs in a horizontal line, check the result of the parity check for each vertical line. In the vertical direction, if no parity error occurs, the image signal obtained as a result of imaging is normal, and noise is mixed in when reading the binarized bit value from the dot pattern for the parity check, causing a parity error. Can be considered to have occurred. Therefore, the normality of the recognition result is confirmed by performing the parity check again on the line in which the error has occurred.

If noise is mixed in when writing the binarization result, an error occurs in the parity check of the horizontal and vertical lines for the error bit. Therefore, it is possible to restore normal data by inverting the bit value at the position where the two lines intersect. Needless to say, the CPU 104 executes these processes.

(7) In the present embodiment, since the object to describe the dot pattern is the printed circuit board, the resist protective film is used for the member having low light reflectivity and the solder film is used for the member having high light reflectivity. , But not limited to this. Further, it is not necessary to form the entire printed circuit board with these members, and at least the part where the pixel code is described may be formed. In addition, it is also possible to use a member having good light reflectivity as a substrate and mount a member having poor light reflectivity on this substrate to create a pixel code in the form of a label. In this case, the label is attached to various objects.

(8) When a pixel code created by laser irradiation as in this embodiment is created, a defective writing of the pixel code may occur due to erroneous laser irradiation or the like. In such a case, the following correction process may be performed.

For example, when the dot pattern of the pixel code indicated by the symbol in FIG. 8 is modified, the dots indicated by the symbol Δ are masked. As a simple method of the mask, it is possible to apply a method of applying the entire left part up to / in the J row in the figure with a paint, to attach a member having a uniform light reflectance, or to perform a cutting process. The same masking process is performed on the right part of the K row in the figure. A new pixel code can be created by performing such a masking process.

In addition, the end of the code area 6, for example,
By masking all the dot patterns on the G, J, and K rows in FIG. 8, the number of digits of the numerical value indicated by the pixel code can be reduced. The mask portion is a partial dot pattern of digit reduction of 1 row or more / 1 column or more. Therefore, it is not necessary to separately provide the code area 6 according to the number of digits of the pixel code.

(9) In this embodiment, an example in which a dot pattern of a pixel code is created by laser irradiation is shown.
In consideration of the simplification of the manufacturing process, the dot pattern can be created by the solder plating process. In this case, the structure of the portion described in the pixel code is the same as in FIG.
0'becomes the solder-plated portion.

Since there is a solder plating process in the manufacturing process of the printed circuit board, there is an advantage that the conventional manufacturing process does not have to be changed if the pixel code is created in this process.

[0064]

As described above, according to the first aspect of the invention, by adding the reference (position) mark to the description of the pixel code, it is possible to read the dot pattern image at the regular position, and the position shift occurs. Therefore, the detection position of the dot pattern is not erroneous. In addition, it is possible to detect an error in the case where the pixel code does not fit in the image pickup screen due to the positional shift amount of the reference mark.

According to the second aspect of the present invention, since the pixel code is recognized (binary conversion) after the position of the image pickup result is corrected on the basis of the reference mark, erroneous recognition may occur even if the installation position of the object is slightly shifted. It never happens.

According to the third aspect of the present invention, by adding the parity to the pixel code and performing the parity check, it is possible to detect the occurrence of erroneous recognition that could not be achieved by the conventional barcode or pixel code recognition method. Become.

According to the fourth aspect of the present invention, by providing the parities for two different directions, even if an error occurs in the parity check in one direction, if the parity check in the other direction is normal, the parity check in the direction in which the error occurs is performed. It is possible to correct the data used for.

According to the fifth aspect of the invention, since the dot pattern is created by laser irradiation, the pixel code can be described even for a small object such as a printed circuit board, and the dot pattern portion is provided with a member having good light reflectivity. Since the contrast is formed on the image pickup screen with respect to the exposed and poorly reflective outer surface member, the binarization accuracy for the image pickup result is improved.

In the invention of claim 6, the numerical value indicated by the defective pixel code can be changed.

According to the seventh aspect of the present invention, the partial dot pattern to be masked is assigned to a numerical value indicating the quality condition of the manufacturing process, and the partial dot pattern is masked immediately before shipping, so that the quality condition content is kept secret. It is possible to effectively use the pixel code, such as

In the eighth aspect of the invention, the dot pattern can be easily described, and the dot code reading accuracy is not impaired due to the characteristics of the pixel code.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a pixel code according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a sectional structure of a printed circuit board to which the present invention is applied.

FIG. 3 is a cross-sectional view showing a partial cross section of FIG.

FIG. 4 is a plan view showing the outer appearance of the upper surface of the printed circuit board shown in FIG.

FIG. 5 is a block diagram showing a circuit configuration of a code recognition device to which the present invention is applied.

6 is a flowchart showing a processing procedure executed by a CPU 104 in FIG.

FIG. 7 is an explanatory diagram showing the contents of dot pattern position correction according to the embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a dot pattern according to another embodiment of the present invention.

[Explanation of symbols]

 1 Horizontal axis 2 Vertical axis 3 Dot pattern 4 Reference (position) dot 5 Reference (position) dot 6 Code area 6'Code area 7 Base material 8 Copper foil 9 Resist protective film 10 Solder film 10 'Solder film exposed part 11 Lattice 12 Detection area 13 Printed circuit board 14 Recognition code 15 Reference hole 16 Bar code α Positional deviation α ′ Positional deviation X Horizontal direction deviation Y Vertical direction deviation L Recognition code area length L ′ Bar code area length

Claims (8)

[Claims] 1. A pixel code recognition method for imaging a pixel code in the form of a dot pattern described on an object, and binarizing a dot pattern in the imaging result to output the numerical value indicated by the pixel code as a signal. A method of recognizing a pixel code, wherein a reference mark indicating the position of the pixel code is added to the pixel code and the reference mark is written on the object. 2. A positional deviation amount between a first position of the reference mark and a predetermined second normal position of the reference mark in the imaging result is detected, and the imaging is performed based on the detected positional deviation amount. The method for recognizing a pixel code according to claim 1, wherein position correction of the result is performed. 3. A pixel code recognition method for picking up an image of a pixel code in the form of a dot pattern described on an object, and binarizing a dot pattern in the image pickup result to output the numerical value indicated by the pixel code as a signal. The line direction parity in the pixel code is added to the description of the pixel code in the form of the presence or absence of a dot, and the dot in the imaging result is obtained using the bit value of the parity binarized from the imaging result. A method for recognizing a pixel code, which comprises performing a parity check on a binarized bit value for a pattern. 4. The method for recognizing a pixel code according to claim 3, wherein the parity is added in a horizontal direction and a vertical direction of the pixel code. 5. A pixel code recognition method for picking up a pixel code in the form of a dot pattern described on an object and binarizing a dot pattern in the picked-up result to output the numerical value indicated by the pixel code as a signal. At least the outer surface of the portion of the object where the pixel code is described is formed of a first member having low light reflectivity, and a second member having high light reflectivity is provided on the inner side of the first member. The pixel code recognizing method is characterized in that the dot pattern of the pixel code is written by exposing the second member by burning away the first member by laser irradiation. 6. A method for recognizing a pixel code, wherein a numerical value indicated by the pixel code is corrected by partially masking a dot pattern of the pixel code described by the method for recognizing a pixel code according to claim 5. .. 7. The digit number of the numerical value indicated by the pixel code is changed by masking all the dots which are located at the end of the dot pattern of the pixel code and which form the dot pattern of one row or one column or more. The method for recognizing a pixel code according to claim 6, wherein: 8. A pixel code recognition method for picking up an image of a pixel code in the form of a dot pattern described on an object, and binarizing the dot pattern in the image pickup result to output the numerical value indicated by the pixel code as a signal.
A pixel characterized in that the dot pattern is described by forming the outer surface of the object of the portion described in the pixel code with a member having less light reflectivity than solder, and performing solder plating on the member. Code recognition method.