JPS6334678A - Bar code reader - Google Patents

Abstract

PURPOSE:To improve the reading capability by providing a means to change the black-detecting level sensitivity corresponding to the number of pieces of thick bars in a read data. CONSTITUTION:A central information processing circuit 11 sets the threshold level of black-detecting level sensitivity at C, and inputs its own outputs P0-P3 to a data comparator 10. If an image sensor 5 reads a bar code 2, a control circuit decides if the bar code 2 is accurately read, and in case of inaccurate reading, decides if the number of thick bars is more or less than two. And, in case the number of the thick bars exceeds two, the threshold is reset to B, but if less than two, reset to A, and the image sensor 5 is allowed to read the bar code 2 once again.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of the Invention The present invention relates to a 2 out of' 5 barcode reading device used, for example, in bankbooks of financial institutions.

(b) Invented back kite The above 2 out of 5 bars is well-known.
] Since a decimal digit is represented by 5 binary digits rJb, it is always written using a thick bar for the 2-tree black bar behind the 5-tree black bar, and a combination arrangement with the remaining 3 thin bars. First, the barcode is read using an optical system such as a lamp and lens, and the image sensor 1 detects the black and white level changes in an analog way, and analyzes whether the black bar is thick or thin. Judging by the Brosset number.

However, in such a control system, the determination of the black bar may become unstable due to fluctuations such as: ■ Changes in the lamp, ■ Uneven barcode printing, ■ Resolution of the image sensor 1, etc. In the past, for example, a comparison signal that followed changes in light was used to change the threshold level for determining white and black, but this method was not able to provide sufficient support, and barcodes with higher performance were used. A reader is desired.

(c) Purpose of the invention In view of the above points, this invention
Focusing on the fact that two of the five black bars in a barcode are always large bars C, the black detection level sensitivity can be lowered depending on whether there are more or fewer thick bars in the read data. The object of the present invention is to provide a barcode reading device that can improve barcode reading performance during rereading operations by increasing the barcode reading performance.

(D) Summary of the Invention This invention includes a comparator that compares the number of thick bars in read data with a set number, and a black detection level sensitivity that is adjusted according to a program according to a change in size with respect to the set number. The present invention is characterized in that it is a barcode reading device including means for changing the barcode.

(E) Effects of the Invention According to the present invention, the black detection level sensitivity can be changed and re-reading can be performed in response to changes in the number of thick bars behind the black bar of the 5-tree tree, so that barcodes can be printed. The reading performance improves against unevenness (blacks are thick and uneven, etc.), and it is also possible to effectively deal with out-of-focus of the optical system and changes between lamp lights.

(f) Examples of the invention An embodiment of the present invention will be described below with reference to the drawings.

Figure 1 shows a device that reads the barcode 2 of a bankbook 1, and an image sensor 4 with the help of an optical system of a lens 3 and a lamp 4.
J5 reads the barcode 2, and inputs it to the A/D converter 8 via the amplifier 6J3 and the peak bold circuit 7 as a log data as shown in FIG. On the other hand, the amplifier output is guided to an integrator 9, and a reference signal generated thereby is inputted to a Δ/1] converter 8 as well.

The Δ/D converter 8 is an m-converter circuit, and converts the level signal of each section of the analog data in FIG. 2 into a 4-bit digital output D.
The signals are input one after another to the BO, B1.82, and B3 terminals of the data comparator 10 as O, DI, B2, and B3.

On the other hand, the central information processing circuit 11 including the read-on memory 12 and the random access memory 13 outputs 4-bit outputs PO, Pl, P2, and P3 to the data comparator 10 according to the set threshold level (black detection level). Input to AO, AI, A2, A3 terminals.

The data comparator 10 is an element that compares the magnitude of A3 human power and 80-83 human power, and makes the output active when A>B, and from its O terminal outputs a signal as shown in Figure 3. is sent to the central information processing circuit 11 and recorded in the random access memory 13, and after the reading is completed, the circuit 11 determines the number of barcode 2 from this and also determines whether the number of thick bars is more or less than 2. seek. Then, when there are more or less than two barcodes, it is determined that the barcode 2 is being read as an error, and the output PO-P3 sent to the data comparison "!S10", that is, the threshold level is changed.

In other words, since the analog signal from the sensor 5 does not have complete contrast and the edges are somewhat blurred, the image is measured with different thicknesses depending on the threshold level. Therefore, threshold levels Δ, B, and C (as shown in FIG. 2) of different sensitivities are recorded in the read-on memory 12. in this case,
At threshold level 8, the black width is determined to be thicker than at threshold level C, and at threshold level B, on the contrary, it is determined to be thinner.

The central information processing circuit 11 normally sets the threshold level C;
Send the outputs PO to P3 as J tlu to the data comparator 10, and compare the outputs with threshold level B when there are more reading errors than 2 trees, and threshold level 8 when there are fewer reading errors. 10.

Next, the operation flow will be explained with reference to FIG.
0 (step 30).

When the image sensor 5 reads the barcode 2 (step 31), the control circuit shown in FIG.
Whether it is more or less than the tree is determined by the previous 1ffl operation (steps 32 and 33).

Then, if there are more than 2 thick bars, set the threshold level to B, and if there are too few, set it to A, and reread the barcode 2 with the image sensor 5 (step 3).
3.34, 35.36>.

Thereafter, in step 37, it is again determined whether barcode 2 has been correctly read.

In this way, when an error occurs in reading the barcode 2, the threshold level of the data comparator 10 is automatically changed according to a pre-programmed procedure depending on the number of thick bars detected, so that the barcode can be read accurately when rereading. can be made possible.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention. FIG. 1 is a control circuit diagram of a barcode reading device, FIG. 2 is an analog data output waveform diagram, FIG. 3 is an output waveform diagram of a data comparator, and FIG. 4 is a diagram of an output waveform of a data comparator. It is an operation flowchart figure. 2...Barcode 5...Image sensor 8
...Δ/D converter 10...Data comparator 11
...Central information processing circuit Figure 4 Operation flow of Figure 1 + Yard

Claims (1)

[Claims] A reading device for 1, 2 out of 5 barcodes, comprising: a comparator that compares the number of thick bars in the read data with a set number; A barcode reader including means for changing detection level sensitivity.