JPS6269379A - Bar code reader - Google Patents

Abstract

PURPOSE:To miniaturize the titled reader and to reduce the cost by providing a presettable counter for calculation of standard width for decision of margin and a ROM for multiplication table and using the presettable counter for detection of the margin. CONSTITUTION:A presettable counter 5 for addition starts its counting action with the final value of a bar width counter 4 up to the next bar for production of the standard width for decision of margin. A ROM 6 for multiplication table performs multiplication of 3.5 times as much as the output of the counter 5. A presettable counter 7 for detection of margin counts down the value obtained by presetting the output of the ROM 6 and decides the margin. Thus the counter 7 and the ROM 6 are used for production of the standard width for decision of margin. While the counter 5 is used for decision of margin. Then the margin can be decided with simple constitution and the reduction of cost is attained with a bar code reader.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention scans a barcode affixed or printed on a product with a laser beam, and reads the information represented by the barcode from the reflected light. Barcode reader @
It is related to.

[Conventional technology]

FIG. 8 is a block diagram of a device used in -1 installation ζ in barcode reading device a. In Figure 3,
(1) is a photoelectric conversion element that converts reflected light from a barcode label into a barcode analog signal Cζ, (2) is an analog processing unit that converts the barcode analog signal into a barcode digital signal, and (3) is a barcode signal A timing generator that generates various timings according to changes in -], (4) is a bar width counter that counts the pulse width (bar width) of the barcode digital signal, and 1'' ω is the count value of (4). A register that temporarily holds fζ until the end of the next bar + 1.1llll is a register that holds the count value held at ((ω) until the end of the next bar $ 2
, IF5 is an adder that adds the output of (!0) and the output of (11), 113) is a multiplier that multiplies the added value added by f13 iζ, and (14) is the adder that adds the output of (!0) and the output of (11). A size comparison W that compares the value and the count value of (4), (81 is a memory unit that stores the bar width data of the bar code, (9) is the bar 1 stored in (8)
This is a barcode decoding unit that analyzes and decodes barcodes based on recorded data lζ.

Next, the 1ζ operation 1ζ will be explained using FIGS. 3, 4, and 5. In Fig. 5, this figure shows the actual barcode reading kj.
Trowel reading JAN (JAPAN ARTFCALN
This figure shows an example of a barcode label standardized as UMBER. The barcode information consists of numbers 0 to 9, each of which corresponds to a character, and each character is represented by two black bars and two white bars, for a total of four trees. The bar 11 wealth using this character fζ is 1 note 1q12 times, employment, 8 times 1, wealth, 4 times i;・]
There are a total of 4 (4) types, and the combination of some of these four types of bars and the combination of white bars and black bars makes a total of 80 items. The numbers 0 to 9 are represented by the combination fζ of these 8 types of bars,
be done. However, one character as a whole is 7 times wider.

(Total width of two white bars and two black bars) Figure 6 shows a 1ζ barcode table. In Figure 6, the black bar's width is 1, and its width is 11.8, and its width is 111.4.
Set it to 1, and do the same. ζ White bar x1, Sae x 012, Width x 00.
The triple width will be called 0004 times, and 'r't=5 will be called 0000. In FIG. 5f, the left guard bar and the left guard bar are 101. Further, the left margin or right margin is located next to the left and right guard bars, and is a white bar space that is seven times the width or more. Furthermore, CζThis barcode is allowed to be enlarged overall (up to x2), j (up to 3 small (XO, S)).

The fα of the laser beam scanning of the barcode label is the fourth
Figure (a) shows tζ, but at this time, the laser beam scanning is non-linear 1ζ high speed, so the laser beam scanning fζ
The corresponding barcode digital signal will also be faster. In order to read the barcode information 1 and 7 explained above (
ζ could be decoded based on the iζ barcode algorithm for each input bar, but this would require an ultra-high-speed processing circuit, and it would be completely impossible to provide the tsuba at a low price. It becomes possible. Considering the complexity of the barcode algorithm and the feasibility of Implementation 1, a microprocessor must be used for barcode γ correction processing. At this time, as explained above, it is not possible to follow the fζ process for each bar of the barcode digital signal that is manually input. As shown in FIG. 4(a)), when the ζ laser beam scans the barcode, the laser beam reflected light from the barcode is converted into an electrical signal by the light receiving element fζ (1). This waveform is shown in Figure 4) (ζ
show. This 11 signal is converted into a barcode digital signal tζ by the analog processing section 1 (2). This waveform is shown as (Qlζ.The barcode digital signal is (Qlζ).
3) is inputted to the timing generating section i, and generates timing for each plate at the time Cζ when the level of the bar code changes, that is, from white to black or from black to white. The bar width counter in (4) is (3)
The timing generator (controlled by the barcode digital) counts the time width from one change point to the next change point using a high-speed clock, and the count number in (4) is the barcode The bar width data is the bar width data of t41.The value counted by the par width counter Cζ of t41 is input to the register #1 of !■ and the memory part fζ of (8). At the load signal shown in Fig. 4 (f),
4) count value is set. In other words, Fig. 4 [F
] As shown by fζ, the IS in the bar of the previous barcode is loaded. Similarly, in register selling 2 in (11), the output of register #1 in "■" is input, and by being controlled by the timing generator in (3), two The previous bar width is loaded.

(In the adder of B, the outputs of tl(B's register #1 and U's register #2 are input, and these two are added. In other words, the output of the register #1 of B and register #2 of U is input. In other words, the output of the register #1 of B and register #1 of U is added. This means that the width of the two previous bars is added. This means that there is always a guard bar before the margin, that is, 10
It is a collection of basic 1 times width of 1, but the barcode label f
ζ is prone to fζ bleeding, blurring, etc. Therefore, it is necessary to accurately calculate the basic width of iζ for margin judgment. Cancels the effects of code label (ζ bleeding, blurring, etc.) and minimizes these errors.
It is possible to do ζ. The reference width calculated by (12) is input to the multiplier Cζ of the CIJ and multiplied. This multiplication value fζ allows calculation of the base value for margin determination. According to the barcode standard, the margin is more than 7 times the basic width, so (lz output is 1131
By multiplying by 8.5 in ζ, a reference value of 7 times width can be obtained. FIG. 4(S) shows the output timing of the multiplier.

The magnitude comparator in the first edition receives the multiplication result of +13] multiplier 2"1' and the bar width counter value of +41, and these two inputs are compared in magnitude. The timing at this time is as follows. As shown in Figure 4 (g) and (S), when the laser beam scan starts scanning the margin, the (4+)(- width counter counts and completes 1, and scans the 7x width point. At the end of the process, the bar width counter value of +41 becomes larger than the multiplication result of the multiplier in (13), and at this point, the magnitude comparator outputs the margin detection signal (1). The barcode decoding unit receives the margin detection signal (1) determined by the circle size comparator and knows that the barcode laser scanning has been completed by 1ζ, and the memory unit (8) up to this point The bar code is decoded by backward processing the bar width information stored in the bar code.

[Problem that the invention seeks to solve]

Since the conventional bar code reading device is configured as described above, it requires a ++3 adder and a circle size comparator as shown in Fig. 8, and the bar requires a count value of about 12 bits. , the same < +121 and +141 require the same bit length, which leads to problems such as the circuit scale becomes complicated and it becomes difficult to provide devices at low cost.

This invention was developed in order to solve the above-mentioned problems, and uses a [ζ presettable counter and a multiplication table ROM to calculate the margin judgment reference width, and a 1ζ presettable down counter to detect the margin. By this,
To enable clue detection with a simple configuration and to provide a device at low cost.

[Means for solving problems]

The barcode reading device according to the present invention has a margin determination criterion 1.
It is constructed by using a presettable counter and a multiplication table ROM for product creation, and an lζ presettable down counter for margin determination.

[Effect]

In this invention, a presettable counter and a multiplication table ROM are used to create a margin judgment reference width, and a presettable down counter is used to judge a margin, thereby making it possible to judge a margin with a simple configuration. can be provided at low cost.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In Figure 1, (1) is a photoelectric conversion element that converts barcode reflected light into an electrical signal (ζ), and (2) is a photoelectric conversion element that amplifies the weak signal from the light receiving element in (1) to a certain level, and converts the barcode's black and white level. 1ζ is an analog processing unit that converts a digital signal lζ according to A bar width counter that counts the time width from one change point of a digital signal to the next change point using a high-speed clock.)5) starts counting from the final value of the bar width counter in (4) and continues counting until the next par. What to do lζ is a presettable counter for creating a margin judgment reference width, (6) is a ROM for a multiplication table for multiplying the counter output of (5) by a factor of 85, +71 is (
The output of the multiplier in 6) is preset, and the margin detection presettable down counter performs margin judgment using (l, I, -], and (8) stores the value of the bar width counter in (41). The memory unit 19) detects that the barcode has been scanned based on the judgment result of the margin detection presettable down counter in 17), and decodes the barcode based on the contents of the memory unit in (8). This is the parcode decoding part.

Next, the operation will be explained using Fig. 1 and Fig. 2. FIG. 2(a) shows how a laser beam scans a 1ζ barcode label as in the case of the prior art.

At this time, the reflected light from the barcode is converted into a barcode analog signal +cg by the photoelectric conversion element 1ζ (1). This waveform is shown in FIG. 2 (1)). This signal is (2)
The barcode digital signal Q is processed by the analog processing section fζ of
lζ transformed. This waveform is shown in (C) )ζ. The barcode digital signal is input to the timing generating section (3), which generates the necessary timing for the level change of the barcode signal, that is, the time point Cζ when the level changes from white to black or from black to white. The +41 barcode T counter is controlled by the timing generator Cζ in (3) and counts the pulse time width of the barcode digital signal using a high-speed clock (the final count value of 4J is the barcode bar width data). The value counted by the +41 bar width counter is input to the addition brissettable counter (5) and the memory section (8). Both (4) and 5) are input to the signal from the timing generator. , that is, the bar width counter load signal (d), the bar IiJ counter, the count enable signal fi-(e) tζ, and the bar Nakamasa counter (4) is controlled by the par row A counter load signal 1ζ.
Therefore, after being initialized, the high-speed clock fζ is input to the bar ξ′ Hatake counter, and the count enable signal goes to L level f.
Count up until you reach ζ.

The count 1 is held until the bar width counter and count enable are at L level and the bar width counter load signal reaches L level 1ζ, and the value at this time becomes the previous bar width data. Addition brisettable counter 15) is also (4
), but at this time, the hold value of the bar width counter of 14+ is loaded, and from the next timing, the count is increased from this value to the next bar width. This is the margin σ
a is always a guard bar, that is, the basic single-width claw combination of 101, but the barcode label has Cζ stains,
Fading, etc. are likely to occur, so margin judgment is performed f
Since it is necessary to accurately calculate the basic width by 1ζ, add the bar width of the two previous bars and the bar 141 of 1 I by 1ζ. Therefore, errors such as rose ζ bleeding and blurring are canceled. It becomes possible to obtain an accurate basic width from fζ. (5) The basic width calculated by the IC is input in ROIvIt for the multiplication table in (6), and this ROM1ζ is the value obtained by multiplying the input value)ζ by 35 times. The standard value of the blank margin is calculated based on the input basic - (1ζ). This situation is shown in Figure 2 (i) 1. (7)
The presettable counter for margin detection is the margin detection presettable counter load (A bow cζ shown in FIG. is set, and at the next timing, the high speed clock fζ starts counting down. This situation is shown in Figure 2 (k))ζ. At this time, the count value in (7) is zero ( ζ is not reached, and at the time of scanning the blank margin, the count is gradually counted down, and the count value in (7) becomes Cζ at the stage when the margin appearance value is scanned.

At this point, the margin detection presettable (7) is down and the counter outputs the margin detection signal (L) in FIG. At this point, the barcode bar data (fζ) has already been stored in the memory section ζ of (8), and the margin detection signal ■ from (7) is input to the barcode decoding section of (9). to be done1ζ
From this, we know that the barcode laser scanning has finished, and up to this point the memory section f? of (8) is stored. : Processes the stored bar width data to decode and reproduce barcode information.

In the above embodiment, the barcode reading device scans the barcode with a laser beam and reads the barcode "111 information" from the reflected light. It may be installed on the signal processing side, and the same effects as in the above embodiment can be achieved.

〔Effect of the invention〕

As described above [ζ, according to the present invention fζ, the brissetable counter and the R for the multiplication table are used to calculate the margin judgment reference width.
OMP, using 3ζ presettable down counter for margin detection.
Since the structure of the present invention is made in an integrated manner, the device can be made cheaper and more compact.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a barcode reading device according to an embodiment fζ of the present invention, FIG. 2 is an explanatory diagram of internal signals in FIG. 1,
Figure 8 is a block diagram of a conventional barcode reading device;
This figure is an explanatory diagram of the internal signals in FIG. 2, FIG. 5 is an example of the structure of a barcode label, and FIG. 6 is a character table of the barcode. (1)...Photoelectric conversion element, (2)...Analog processing section, (3)...Timing generation section, (4j...Bar width counter, 5)...Presettable counter for addition , (6)...ROM for multiplication table, +71...
- Presetable counter for margin detection, (8)...Memory section 19+...Barcode decoding section. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] A photoelectric conversion element that scans a barcode label with a laser beam and converts the reflected light into a barcode analog signal, an analog processing unit that converts the barcode analog signal into a barcode digital signal, and generates the necessary timing for each part. a bar width counter that counts the pulse width (bar width) of the barcode digital signal; a presettable addition counter that sets the count value of the bar width counter and adds the next bar width; A multiplication table ROM that calculates a margin reference value based on the addition of a double counter, a margin detection presettable down counter that performs margin detection by presetting this multiplication result value and counting down from this preset value, and a bar. A barcode reading device comprising: a memory section that stores bar width data of a code label; and a barcode decoding section that analyzes and decodes the stored barcode data.