JPS62280978A - Bar code detecting device - Google Patents

Abstract

PURPOSE:To stably detect a bar code even if a bar code detection distance varies by permitting an automatic focussing means to adjust a distance between a light converging means and an image sensor and forming the image of reflected light from the bar code on an image sensor. CONSTITUTION:Assuming that the bar code 2 lies in a position (distance from the light converging means 3) X 240mm, the distance (y) between the image sensor 4 and the light converging means 3 is set to 34.0mm. Since the field depth (x) equals 240+ or -30mm (A'), the bar code can be detected. If the bar code is shifted to a position x=58mm (B), it is out of the field depth A, and therefore the bar code 2 cannot be detected. However, a distance measuring part detects the position of the bar code 2, and shifts the position of the light converging means 3, thereby y=46.5mm can be obtained. The field depth changes to x=128+ or -30mm (B'), and the bar code can be detected.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to a barcode detection device used in POS, logistics, production management, etc.

2. Description of the Related Art In a conventional barcode detection device of this type, as shown in FIG. The light is focused on the image sensor 34, and the received light signal, which is the output of the image sensor 34, is subjected to noise component removal and binarization by the received light signal processing circuit 36, and the output is taken into the microcomputer 36 and decoded. .

Problems to be Solved by the Invention However, the distance between the barcode 32 and the barcode detection device (hereinafter referred to as detection distance) is limited to a fixed area due to the depth of field of the light condensing means 33. was.

Therefore, when detecting a barcode, it is necessary to bring the barcode label within the fixed area. For example, when detecting a barcode affixed to an item flowing on a conveyor, the barcode had to be positioned on the conveyor so that it fell within the area. Furthermore, if the type of item changes and the barcode cannot be positioned within the area, the light condensing means 33 must be replaced with a more suitable one. When using a parcordon stem for the purpose of improving productivity, there are problems in that the above-mentioned positioning equipment is required, and in flexible production, the above-mentioned light condensing means 33 needs to be replaced and adjustments are made accordingly. .

Means for Solving the Problems The present invention solves the above problems by providing an illumination means for illuminating a barcode, a condensing means for condensing light reflected from the barcode, and an image The apparatus includes a sensor, and automatic focus adjustment means for adjusting the distance between the light condensing means and the image sensor and focusing the reflected light from the barcode on the image sensor.

Effect With the above configuration, even if the barcode detection distance changes,
The automatic focus adjustment means adjusts the distance between the condensing means and the image sensor to form an image of the reflected light from the barcode on the image sensor.

Embodiment FIG. 1 shows an embodiment of the barcode detection device of the present invention. The light emitted from the illumination means 1 is the barcode 2
This reflected light is imaged on the image sensor 4 via the condensing means 3. This light reception signal is converted into a bar width signal by the light reception signal processing circuit 5, and decoded by the microcomputer 6. In this embodiment, the illumination means 1 is a 100 W halogen lamp, the condensing means 3 is a three-piece combination lens with a focal length f = 30 mm and an effective diameter D = 11 mm, and the image sensor 4 is a 2 o
A 4s bit C0D-dimensional sensor was used.

The automatic focus adjustment means 7 is composed of a distance measuring section 8 that detects the position of the barcode 2 and a focusing means driving section 9. In the distance measuring section 8, the wavelength λ=880 nm.

Infrared output Po=smW! , KD10 is condensed by a light projecting lens 11 with a focal length f = 20 rtan, irradiates the barcode 2, and the reflected light is passed through a light receiving lens 12 with a focal length f = 20 m to a light receiving surface with a length of the light receiving surface. The image is formed on a one-dimensional PSD 13 with a length of 10 m.

The spot light of the infrared LED 10 irradiated onto the barcode is irradiated onto the PSD in accordance with the distance from the barcode 2.
Since the image is formed on the PSD output current, distance information can be obtained from the distance measurement signal processing circuit 14 based on the principle of triangulation. The condensing means driving section 9 includes a condensing means driving circuit 15 and a condensing means driving mechanism section 16 composed of a pulse motor and a slide unit. 30m
m/ S6C + minimum positioning accuracy of 0.5 m was adopted. The microcomputer 6 calculates the amount of extension of the condensing means 3 based on the distance information from the distance measuring section 8 so that the barcode 2 enters the depth of field of the condensing means 3,
A moving direction signal and a pulse signal indicating the amount of movement are sent to the condensing means driving mechanism 1 and the like to move the condensing means 3. Therefore, the barcode 2 always falls within the depth of field of the light collecting means 3.

FIG. 2 shows an example of operation when the barcode detection distance changes. First, in FIG. 2a, it is assumed that the barcode 2 is located within a distance of 240 animals (hereinafter referred to as "rx") from the condensing means 3. At this time, the distance (hereinafter referred to as "y") between the image sensor 4 and the condensing means 3 is set to 34.0 mm. Since the depth of field is X=240±30 area (A'), the barcode can be detected. Next, assume that the barcode changes to position (B) at x==58++o++.

This is outside the depth of field A' at point B in Figure 2, so
Barcode 2 cannot be detected in the state shown in Figure 2B. Therefore, it cannot be detected by a conventional barcode detection device in which the positions of the image sensor 4 and the condensing means 3 are fixed and the depth of field is constant. However, in this embodiment, the distance measuring section 8 detects the position of the barcode 2, and the focusing means 3
Move the position of. As a result, 7=46.5 m, and the depth of field also changes to x=128±3o ran (B'). Therefore, barcode detection becomes possible. In this example, barcode detection was possible within the range of detection distance X=98 to 27 om.

In this embodiment, the automatic focus adjustment means 7 that moves the condensing means 3 has been described, but the same effect can be obtained by moving the image sensor 4.

Furthermore, as an automatic focus adjustment method, it is effective to use not only the distance measurement method described above but also a focus detection method.

Effects of the Invention As described above, according to the present invention, it is possible to stably detect a barcode even if the barcode detection distance changes, so it is extremely useful for process control in high-mix, low-volume production.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram of a barcode detection device showing an embodiment of the present invention, FIG. 2 is a plan view of essential parts showing an example of the operation when the barcode detection distance of the device changes,
The figure is a block diagram of a conventional barcode detection device. 1...Lighting means, 2...Barcode,
3... Light collecting means, 4... Image sensor, 6... Microcomputer, 7...
...Automatic focus adjustment means, 8...Distance measuring section, 9...
. . . Concentrating means driving section, 15 . . . Concentrating means driving circuit, 16 . . . Concentrating means driving mechanism section. Figure 1 Figure 2 ■ (α) (b) Figure 3 32 barcode

Claims (2)

[Claims] (1) An illumination means for illuminating the barcode, a condensing means for concentrating reflected light from the barcode, an image sensor, and a distance between the condensing means and the image sensor is adjusted. A barcode detection device comprising automatic focus adjustment means for forming an image of reflected light from the barcode on the image sensor. (2) A patent claim in which the automatic focus adjustment means includes a distance measuring section that detects the position of the barcode, and a focusing means driving section that moves the focusing means via a microcomputer based on distance information from the distance measuring section. The barcode detection device according to item 1.