JPS601674B2 - Identification code reading method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an identification code attached to a cylindrical object (hereinafter, this identification code is referred to as an ID code).

) is related to a method of automatically reducing In recent years, various automatic conveyance systems have been developed for the purpose of labor saving in all industrial fields where business activities involve processes that require the movement of goods (raw materials, intermediate products, products, etc.) in some way.

Examples include truck terminals, automatic sorting and conveyance systems outside product distribution centers in large-scale retail stores, and can conveyance systems in textile factories. When designing such an automatic conveyance system, the biggest technical challenge is the development of a sorting classification detection method when there are many types of objects to be conveyed and they must be distributed according to their respective sorting categories. When the object is rectangular in shape, a technology has been completed and put into practical use that attaches an m-code such as a barcode to the side surface and optically reads and distributes the m-code. However, in the case of non-rectangular shaped objects, especially cylindrical objects such as test tubes and beakers used in hospital sample testing processes, no proper method has yet been developed and the reality is that the process relies on manual labor. It is. I attached to a cylindrical object
This is because the D code is marked on the tube wall with a curve around the entire circumference or close to it, which complicates the detection mechanism. In other words, in order to capture the entire ID code written on the circumference of the tube, it is necessary to rotate the detection unit around the object, or
Alternatively, it is necessary to keep the detection unit fixed and rotate the object; in the case of the former,
In practical use, it is difficult to extract the detection signal to the outside, and in the latter case, mechanical vibrations are applied to the contents, making it particularly unsuitable for containers containing samples to be chemically analyzed. This was the biggest obstacle. The inventors of the present invention have finally completed the present invention as a result of intensive research into a method for automatically decoding the ID code attached to a cylindrical object, which previously had to be done manually.

In other words, the gist of the present invention is to place a cylindrical object around which a label with an identification code is attached at the center of a conical mirror with a mirrored inner surface, and to display an image of this identification code on the conical surface. This identification code discussion method is characterized in that an m-code is read by forming an image on a semi-transparent material using a lens placed above a mirror and making this image incident on a solid-state camera consisting of a two-dimensional image sensor. The present invention will be described in more detail below with reference to the drawings. FIG. 1 is a side view showing an example of an apparatus used for carrying out the present invention. In the same figure, a cylindrical object 1 has a label 2 on which an ID code is written This cylindrical object 1 is placed in the center of a conical mirror 3 whose inner surface is mirror-finished.

A solid-state camera 5 comprising an optical system and a two-dimensional array of image sensors is installed above the conical mirror 3 with a glass 7 and a translucent material 4 such as ground glass in between. In the ID code detection mechanism configured as described above, the image of the ID code written on the label 2 is refracted by the conical mirror 3 and formed onto the semitransparent material 4 by the lens 7.
At this time, the image of the m code formed on the semi-transparent material 4 is an annular image 6, as shown in FIG. If this entire image 6 is captured by the optical system of the solid-state camera 5 and formed on a two-dimensional array image sensor, a photocurrent output corresponding to the ID code can be obtained. In the present invention, since the conical mirror 3 is used as a refractive medium for the optical path, even if the m code is written all around the tube wall of the cylindrical object 1, it will not be possible to reach the translucent material 4 from any position. The distance is the same, and there is no need to take into account fluctuations in photocurrent output due to loss of light amount, etc.

Note that the photocurrent signal output from the solid-state camera 5 has different values depending on the image of the ID code, so the bright and dark areas are divided into two (1.0) type signals using an appropriate reference value, and this is converted into a digital signal. If the m code is stored in memory and reproduced as a combination of bits (1.0), the ID can be obtained using a combination of known techniques.
The content of the code can be determined.

The number of elements of the image sensor may be determined based on the shape and number of digits of the m code. As described in detail above, according to the present invention, it is possible to automatically read an ID code written on a cylindrical object without using any moving parts, and it is possible to automatically read an ID code written on a cylindrical object without using any moving parts. , alphabetic characters, etc. can also be used, and will greatly contribute to the promotion of rationalization in business fields that handle many cylindrical objects, such as inspection work in hospitals.

EXAMPLE In order to understand the ID code detection accuracy according to the present invention, an experiment was carried out using the apparatus shown in FIG. 1 under the following conditions.

{1' ID code; A code consisting of a combination of five digit numbers printed in B font was attached to the test tube.

[2) Group camera; 2-dimensional arrangement C of 128 x 128 elements
A CD type image sensor was used.

'3} ID code determination: A minicomputer with a main storage capacity of 16KW was used.

As a result, it was confirmed that ID codes could be detected with a very high degree of accuracy with a misreading rate of 0%.

[Brief explanation of drawings]

FIG. 1 is a side view showing an example of an apparatus used to carry out the present invention, and FIG. 2 is a plan view showing an image formed on a translucent material in the apparatus of FIG. In Figure 2, 1 is a cylindrical object, 2 is a label with an ID code written on it,
3 is a conical mirror, 4 is a translucent material, 5 is a solid-state camera, 6 is an image, and 7 is a lens. Ice/Picture soup 2

Claims (1)

[Claims] 1. A cylindrical object with a label with an identification code attached around it is placed in the center of a conical mirror with a mirrored inner surface, and the image of this identification code is placed above the conical mirror using a lens. An identification code reading method characterized by reading an identification code by forming an image on a semi-transparent material and making the image incident on a solid-state camera comprising an optical system and a two-dimensional image sensor.