JPH04333185A - Scanner device - Google Patents

Abstract

PURPOSE:To correctly read image data by always forming reflecting light from an object to be detected in a photodetecting part even in the case the distance from the object to be detected to photodetection changes. CONSTITUTION:The light quantity of reflecting light from the object to be detected is detected by an optical sensor 9 so that the position of a lens is inferred in a fuzzy inference device 21 with the output of the optical sensor 9 as an input variable. Inference result in the fuzzy inference device 21 is supplied to a lens driving device 6 so that the lens is shifted by the lens driving device 6 in accordance with the quantity of reflecting light changing by the exhibition position of the object to be detected.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanner device, such as a barcode reader applied to a POS system, which receives reflected light from an object at a light receiving section and reads image data.

0002

2. Description of the Related Art Scanner devices that emit light from a light emitting section onto an object to be detected, receive reflected light from the object at a light receiving section, and read this as image data include, for example, a POS system. There are barcode readers that read barcodes attached to products. As this barcode reader, there is a fixed type barcode reader in which a light emitting part and a light receiving part are installed on a table, and a laser beam is generally used as the light emitting part in this fixed type barcode reader.

0003

However, in conventional laser beam type bar code readers, the focal length of the light receiving section that receives reflected light from the object to be detected is fixed. In this way, in a scanner device in which the focal length of the light receiving section is fixed, if the distance between the object to be detected and the light receiving section causes an error with respect to the focal length, the reflected light will be diffused at the light receiving section and the image will be formed. Therefore, there was a problem that it became impossible to read the image data accurately. Such problems frequently occur in fixed barcode readers.

An object of the present invention is to measure the distance between the object to be detected and the light receiving section based on the amount of light reflected from the object to be detected, and based on this measurement result, a sensor is installed in the optical path of the reflected light. To provide a scanner device capable of accurately reading image data even if the position of an object to be detected changes by changing the focal length of a lens so that reflected light is accurately focused on a light receiving part. be.

[0005]

[Means for Solving the Problems] A scanner device of the present invention is a scanner device that reads image data by receiving reflected light from an object to be detected by a light receiving section, and is arranged in the optical path of the reflected light and focused. A lens equipped with a driving means for changing the distance, an optical sensor that detects the amount of reflected light, and a focal length of the lens based on a predetermined fuzzy rule and membership function using the detection output of the optical sensor as an input variable. A fuzzy inference means for inferring and outputting the inference to the driving means is provided.

[0006]

In the present invention, the amount of reflected light distributed from the object to be detected is detected by the optical sensor, and the focal length of the lens is inferred by the fuzzy inference means using the detection output of the optical sensor as an input variable. This inference result is supplied to a lens driving means arranged in the optical path of the reflected light from the object to be detected, and this driving means changes the focal length of the lens based on the inference result. Therefore, when the presentation position of the object to be detected approaches or moves away from a predetermined position, the focal length of the lens is changed accordingly, and the reflected light from the object to be detected always forms an image on the light receiving section.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the configuration of a scanner device according to an embodiment of the present invention. The scanner device 1 includes a laser beam 10 as a light emitting section, and this laser beam 10
From there, a laser beam is irradiated onto an object 11 to be detected, such as a bar code affixed to a product, for example. This laser light is reflected on the surface of the object to be detected 11, and the reflected light is distributed to the light receiving section 8 via the mirror 2, the hologram scanner 3, and the lenses 4 and 5.

The lens 4 is equipped with a lens drive device 6, which is a drive means of the present invention, and the lens drive device 6 moves the lens 4 in the direction of arrow L or R in the figure. This movement of lens 4 changes the focal lengths of lenses 4 and 5. Further, the reflected light that has passed through the lenses 4 and 5 is also distributed to the optical sensor 9 by the half mirror 7. This optical sensor 9
outputs a voltage according to the amount of received light.

FIG. 2 is a block diagram showing the configuration of a control section included in the scanner device. The output of the optical sensor 9 is input to the fuzzy inference device 21 as an input variable. Fuzzy rules and membership functions are set in advance in the fuzzy inference device 21, and the fuzzy inference device 2
1 performs fuzzy inference based on this fuzzy rule and membership function. This fuzzy inference device 2
For example, the membership functions shown in FIG. 3 are set in 1, and FIG. 3(A) represents the antecedent membership function, and FIG. 3(B) represents the consequent membership function. The fuzzy inference device 21 determines the corresponding label and degree of membership of the input variable in the antecedent membership function of FIG. 3(A), and selects the fuzzy rule having this label. Examples of fuzzy rules preset in the fuzzy inference device 21 include if(x=PL) then(y=PL)...
Formula 1if(x=PM) then(y=PM)...
Equation 2if(x=PS) then(y=PS)・
・・Formula 3if(x=ZR) then(y=ZR
)... Formula 4if(x=NS) then(y=
NS)... Equation 5, etc. Here, formula 1 means that when the amount of light received by the optical sensor 9 is quite large and the distance to the object to be detected is quite short, the lens 4 is moved quickly in the direction of arrow R shown in FIG. 2 is the optical sensor 9
If the amount of light received is a little large and the distance to the object to be detected is a little short, this means that the lens 4 should be moved a little faster in the direction of arrow R.

The fuzzy inference device 21 selects a fuzzy rule whose antecedent part includes the corresponding label from among these fuzzy rules, and calculates the membership function of the consequent part label in this fuzzy rule (see FIG. 3(B)). ) is transformed by the degree of affiliation, and its center of gravity value is output to the lens driving device 6 as an inference result. The lens driving device 6 moves the lens 4 based on this inference result.

As described above, according to this embodiment, the optimum focal length can be obtained from the output of the optical sensor 9 by utilizing the fact that the amount of light received by the optical sensor 9 changes depending on the distance to the detected object 11. Move the lens 4 to the desired position.

0012

According to the present invention, the focal length of the lens placed in the optical path of the reflected light can be changed depending on the amount of reflected light from the detected object that is received by the light receiving section, and the position of the detected object can be changed. Even if the lens changes, the focal length of the lens can be finely set using fuzzy reasoning according to the distance from the object to the light receiving part, and the reflected light is always focused on the light receiving part.
This has the advantage that image data can be read accurately in the light receiving section.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of a scanner device that is an embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of a control section of the scanner device.

FIG. 3 is a diagram showing an example of membership functions set in the fuzzy inference device 2 of the control unit.

[Explanation of symbols]

1-Scanner device 4-Lens 6-Lens drive device 8-Light receiving part 9-Light sensor 21-Fuzzy inference device

Claims (1)

[Claims] 1. A scanner device that reads image data by receiving reflected light from an object to be detected by a light receiving section, comprising: a lens disposed in an optical path of the reflected light and including a driving means for changing a focal length; an optical sensor that detects the amount of reflected light, and fuzzy inference that infers the focal length of the lens based on predetermined fuzzy rules and membership functions using the detection output of the optical sensor as an input variable and outputs it to the driving means. A scanner device comprising: means.