JPS5961704A - Dimension measuring apparatus - Google Patents

Abstract

PURPOSE:To achieve an accurate measurement eliminating the need for considering the material condition of an object to be measured by providing a diffusion plate for diffusing light from a lamp, an optical system for forming an image of the diffusion plate at the position where thick surface to be measured of the object and the like. CONSTITUTION:Light emitted by a lamp 1 is uniformized with a diffusion plate 2 to form a bright surface with an area. A condenser lens 3 is used to form an image of the diffusion plate 2 at P, the end face of an object 4 to be measured, namely, near the mesuring surface. At this point, the image formed on the surface P to be measured is made large sufficiently as compared with the section of the object to be measured so that not only a parallel light but also components of lights in the directions L1 and L2 radiate the object being measured. Thus, an image of the diffusion plate 2 ismade on the measuring surface P both upward and downward centered on the object 4 to be measured. This is formed with a light receiving lens 5 to measure the dimension of the thickness thereby enabling accurate measurement eliminating the need for considering material of the object to be measured.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention captures the wall thickness of a plate or pipe at a single point where there are multiple measurement positions, and measures the wall thickness using a line sensor camera using a photodiode array. A dimension measuring device is provided.

Structure of conventional example and its problems Conventional wall thickness measurement method uses indirect stiffness (contact) type mitarometer or dial gauge, so the object to be measured is flexible like rubber. In some cases, it was not possible to measure accurate dimensions.Furthermore, there was a risk of scratches or the like on objects with soft metal surfaces during measurement.

Purpose of the Invention The purpose of the present invention is to eliminate the two disadvantages and provide a device R that can accurately measure wall thickness, etc. without contact, without having to consider the material condition of the object to be measured. do.

Structure of the Invention In order to achieve the above-mentioned object, the present invention attempts to measure dimensions using a line sensor camera, a telecentric aperture, and an optical system that forms an image of light in the vicinity of a measurement surface.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2. In the figure, 1 is a rung, 2 is a diffusion plate that creates a uniform diffusion surface, and 3 is a condenser lens, which projects the light from the diffusion surface of the diffusion plate 2 onto the measurement surface P. 4 is a plate-shaped, tubular, etc., object to be measured; 6 is a light receiver 1 that receives an image of the fixed point P;
6 is a precentric diaphragm, which extracts only the parallel component of the light entering the light receiving lens 6. 7 is a line sensor camera with a 7-oto-tiode array, and its dimensions are (open side) fl1 minute.

Next, the operation of the embodiment described in - will be explained. )'l; emitted by the lamp 1 is made uniform by the diffuser plate 2, and becomes /ζbrightness]n1 having a certain area. The total condensing lens 3 forms an image of the diffuser plate 2 on the end face P of the object to be measured 4, that is, near the measurement surface. At this time, an image d1 formed on the measurement surface P, a cross section of the object to be measured, and a sufficiently large image are created so that the parallel rays can not reach the object to be measured.

A light component in the L2 direction is irradiated. Therefore, on the measurement surface P, there are two scattering plates 1 and 2 in both directions, centering on the skin measurement object 4.
A statue of This is imaged by the entire light receiving lens 5 onto the 7-otiode array 2, and the entire wall thickness dimension is measured.

In other words, there is a photodiode to be measured.
is in the dark part, and the rest becomes intercooled i, and by counting the dark part fτ11, it is possible to measure the ('° method).

A Te1 nocentric diaphragm 6 is installed at the focal plane of the light receiving lens 5, and only the parallel components of the light entering the light receiving lens are imaged on the photodiode array 7J2. Even if it moves a little in the optical axis direction from Nbe, accurate dimensions can be measured without any problem. “Furthermore, even if the object 4 to be measured is 11′, l:IIA in the optical axis @11] direction at an angle θ as shown in FIG. 2, there is light of the Ll and L2 components. X in diagram (a)
It is possible to measure not just one dimension but the X2 dimension in FIG. 3(0). The X2 dimension is not the true wall thickness dimension, but even if the angle θ is 5 degrees, the X2 dimension is 1'), 966 times f'? , degrees, so it falls within the error range of 1/100 to -1,000. Therefore, there is no problem in measuring the wall thickness of general iron plates and steel pipes.

Effects of the Invention According to the present invention, it is not necessary to select all the objects to be measured.
Dimensions such as wall thickness can be measured accurately and without contact with simple positioning without changing lens magnification.

Furthermore, there is no fear of damaging the object to be measured.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a dimension measuring device according to an embodiment of the present invention, Fig. 432 is an enlarged block diagram of the same main part, and Fig.
＋"jl&yomeasurement'] This is a top view of Houda J. 1 Lens, 2...diffuser, 3...Mountain collection) 1
0 lens, 4 ・ Wave i11'l 'jib' attacked,
5... Light receiving lens, 6... Precentric aperture,
7. River: Photodiode array.

Claims (1)

[Claims] A diffuser plate that completely diffuses the light from the lamp, an optical system that forms an image of the light diffuser plate at a position where the measurement thickness surface of the object to be measured is placed, a light receiving lens that receives the image, and the light receiving lens. A dimension measuring device consisting of a telecentric diaphragm placed at the focal point of the telecentric diaphragm 9 and a line sensor camera using a photo-die thought array that detects the light passing through the telecentric diaphragm 9.