JPH096890A - Light source adjustment method for barcode reader - Google Patents

Abstract

(57) [Summary] [Purpose] The initial setting of the light projection amount is easy and can be automated. [Structure] An alignment pattern obtained by emitting a light from a light source 7 to a test pattern 8 in which information is recorded in a predetermined pattern, and an alignment pattern obtained by a read signal output from the light receiving section 4 upon which the light is incident and a preset ideal orientation The pattern is compared and examined, and the light emission time of the light source when the difference between the two falls within a fixed value or less is initialized as the best light emission time in the light source 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention sets a best light projection state in a bar code reader which emits reading light from a light source toward a bar code symbol and optically reads information recorded in the bar code symbol. The present invention relates to a light source adjustment method for a bar code reader that can be used.

[0002]

2. Description of the Related Art Various bar code readers have been developed and used for reading bar code symbols printed on bar code labels. For example, as a typical example of such a bar code reader, as shown in FIG. 3, a light projecting means 10 such as a light emitting diode that emits a predetermined reading light toward a bar code symbol described in a bar code label 100.
1 and the reflected light emitted from the light projecting means 101 and reflected by the bar code label 100 is incident on the light receiving means 103 such as a CCD image sensor through the imaging lens 102, converted into a predetermined electric signal, and information is obtained. A configuration for reading is known.

By the way, in the bar code reader having such a structure, the light projecting section and the like are individually initialized for each bar code reader, so that the light projecting amount is adjusted using, for example, a volume. The position balance is adjusted so that the received light amount is evenly distributed over the entire bar code label.

[0004]

However, since such an initial adjustment work is usually a troublesome work to be performed manually one by one, the workability is lowered, which is a serious problem.

In view of the above circumstances, an object of the present invention is to provide a light source adjusting method for a bar code reader in which the initial setting operation of the light projection amount is easy and can be automated.

[0006]

That is, the present invention provides a bar code reader which emits reading light from a light source toward a bar code symbol and optically reads the information recorded in the bar code symbol. The light emitted from the light source is emitted to the recording medium on which the information is recorded, and the alignment pattern obtained by the read signal output from the light receiving unit which entered the light is compared with the preset alignment pattern.
The light source emission time when the calculation is performed and the difference between the two is within a certain value or less is initially set as the best light emission time in the light source.

[0007]

According to the present invention, a recording medium on which information is recorded in a predetermined pattern is made to emit light from a light source, and an alignment pattern obtained by a read signal output from a light-receiving section which entered the light and a preset setting. The alignment pattern is compared and calculated, and the lighting operation time is repeatedly changed under the control of the control unit as appropriate until the deviation between the two falls below a certain value. When the control unit detects that the deviation has fallen below a predetermined value, the light source light emission time at that time can be initialized as the best light emission time in this light source.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a light source adjusting device to which a light source adjusting method for a bar code reader according to the present invention is applied. The light source adjusting device includes a control unit 1, a transistor 2, an imaging lens 3, and a light receiving device. Part 4, amplifier 5,
The A / D converter 6 is provided. In the figure, reference numeral 7 is L
A light source using an ED or the like, and 8 shows a test pattern provided exclusively for adjusting the light source time.

The control unit 1 operates each of the light sources 7 (7A and 7B) to calculate the orientation pattern at the lighting time, and stores the calculated orientation pattern (hereinafter referred to as a calculation pattern) in advance. Compared with the set ideal orientation pattern (hereinafter referred to as the ideal pattern)
The calculation is performed to determine whether or not the difference between the two is less than a certain value. In the control unit 1 of this embodiment, the input is connected to the output of the A / D conversion unit 6, and the output is connected to each transistor 2 (2A / 2B),
The operation of each of these transistors 2 (2A and 2B) is controlled to change and adjust the lighting time of each light source 7 (7A and 7B).

Each of the transistors 2A and 2B corresponds to each of the light sources 7A.
7B is connected to each of them, and the light source is turned on by switching operation.

In the light receiving portion 4 of this embodiment, for example, a CCD
(Charge-coupled device) An image sensor is used, and when the reading light emitted from the light source 7 (7A, 7B) and reflected back by the test pattern 8 is received, a reading signal corresponding to the intensity of the received reading light is received. The output is connected to the input of the amplifier 5.

The amplifier 5 is configured to increase / enlarge the S / N ratio of the read signal output from the CCD image sensor of the light receiving section 4 to identify / remove noise contained in the read signal. The output is connected to the input of the A / D converter 6.

The A / D converter 6 is for converting the analog signal output from the amplifier 5 into a digital signal, and the output is connected to the input of the controller 1.

Next, a light source adjusting method for a bar code reader according to the present invention will be described with reference to FIG. 2 using the light source adjusting device of the previous embodiment.

Under the control of the control unit 1, a predetermined control signal is output to each transistor 2 (2A / 2B) for a specific time. Then, each of the transistors 2 (2A and 2B) that receives the control signal performs a switching operation for the signal input time, and each light source 7 (7A and 7B) performs a lighting operation for that time to emit the read light (first 1 step S1).

Next, the emitted reading light is reflected at each part of the test pattern 8 at the same time, and then enters the CCD image sensor of the light receiving part 4 through the imaging lens 3 (second step S2).

The CCD image sensor on which the reading light is made incident, through the amplifier 5 and the A / D converter 6, a reading signal having an intensity corresponding to the light intensity of the reading light made incident on the pixel corresponding to each part. It is output to the control unit 1. And
The control unit 1 that receives this read signal receives the test pattern 8
The calculation pattern in which the light intensity is distributed is calculated and detected for each position corresponding to each part of (3rd step S3).

At the same time, comparison / calculation with the ideal pattern is performed, and a light intensity difference is obtained for each corresponding position between the calculated pattern and the ideal pattern (fourth step S).
4).

If the difference is within a fixed value, the lighting time of the light source 7 (7A, 7B) is numerically determined as the light emitting time of the light source, and the initial setting of the light source operating time is completed. Yes (fifth step S5).

Further, in both of these patterns, if there is a difference in the light intensity at the corresponding position that exceeds the above predetermined value, the control unit 1 judges this and repeats from the first step S1 again. Repeat the operation of.

In this way, the initialization operation of the light source operating time can be automatically performed by the control unit 1.

[0022]

As described above, according to the present invention, a recording medium on which information is recorded in a predetermined pattern,
The light source is turned on for a desired time by the control signal from the control unit, and at that time, the alignment pattern obtained from the read signal output from the light receiving unit on which light from the light source is incident is compared with the preset alignment pattern. The lighting operation time is repeatedly changed under the control of the control unit until the difference between the two is less than a certain value, and when the control unit detects that the deviation is less than the predetermined value, the light source at that time is calculated. Since the light emission time can be initialized as the best light emission time in the light source, that is, the light emission time can be automatically initialized by the control of the control unit, there is an effect that the troublesome and troublesome setting work is released.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a light source adjustment device of a bar code reader according to the present invention.

FIG. 2 is a flowchart showing a light source adjustment method for a barcode reader according to the present invention.

FIG. 3 is a schematic configuration diagram showing a conventional example.

[Explanation of symbols]

 1 Control unit 2 (2A · 2B) Transistor 4 Light receiving unit 7 (7A · 7B) Light source (LED) 8 Test pattern

Claims (1)

[Claims] 1. A bar code reader which emits reading light from a light source toward a bar code symbol and optically reads information recorded on the bar code symbol, wherein the light source is on a recording medium on which information is recorded in a predetermined pattern. When the deviation between the two is less than a certain value, the alignment pattern obtained by the signal output from the light receiving unit that emits this light is compared and calculated. A light source adjustment method for a bar code reader, wherein a light source light emission time is initially set as a best light emission time of the light source.