JPS63236909A - Shape measuring instrument - Google Patents

Abstract

PURPOSE:To measure the variation and defect of a body to be measured at the same time without any mutual operation by photodetecting reflected light and scattered light from the body to be measured by a two-dimensional image pickup element and separating and processing them by an image processing part. CONSTITUTION:If the body 3 to be measured has the defect, a light spot projected on the body 3 to be measured is scattered at the part. Consequently, a light spot shown in a figure is formed on the two-dimensional image pickup element 5. This spot is separated by the image processing part into the reflected light and scattered light. Namely, when >=2 light spots are detected in the picked-up two-dimensional signal, a spot which is close to a circle is decided and in other cases, it is decided that the light spot is generated by the scattering. Namely, K=(L/S) (L: peripheral length, S: area) and the spot is closer and closer to the circle as K is smaller and smaller. Then, the displacement of the reflected light from the position of the center of gravity is calculated to find the defect from the position and intensity of the scattered light.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a shape measuring device that optically measures the shape of an object or the displacement of an object.

BACKGROUND OF THE INVENTION One of the well-known non-contact ranging methods is the beam decentering method. This configuration, as shown in Figure 3,
A parallel beam emitted from a light source 1 is eccentrically incident on an objective lens 2, and the reflected light from the object to be measured 3 is sent to an objective lens 2.
The beam is received again by the beam sinter 4, the position of the beam is measured by the position detection element 11, and the arithmetic processing unit 1
2 to calculate the displacement. The principle is that when the object to be measured 3 moves up or down in the optical axis direction of the objective lens 2, the beam incident position on the objective lens 2 changes, and the beam position on the optical position detection element 11 changes accordingly. I am by.

Problems to be Solved by the Invention However, with the above configuration, if there is a defect such as a fine scratch, foreign object, or pinhole on the object to be measured other than the projected light spot, the light will be scattered and the light will be scattered on the optical position detection element 12. The light spot will be spread out in a specific direction. Therefore, there was a problem in that the center of gravity of the light spot shifted, resulting in measurement errors.

In view of the above-mentioned problems, the present invention provides a shape measuring device that can accurately measure the shape even if a defect smaller than the projected light spot exists on the object to be measured.

Means for Solving the Problems In order to solve the above problems, the shape measuring device of the present invention has the following features:
A lens installed eccentrically with respect to the optical axis of the light source and flow source, a two-dimensional image sensor that receives reflected light and scattered light from the measurement target, and a two-dimensional image sensor that separates the reflected light component and scattered light component from the imaged signal. It consists of an image processing unit that calculates the location and defect of a spot.

Effect of the Invention With the above-described configuration, the present invention receives reflected light and scattered light from the object to be measured using a two-dimensional image sensor, so that the image processing section can distinguish between reflected light and scattered light, and the center of gravity of the reflected light can be determined by By performing shape measurement, it is possible to determine the presence or absence of defects and their size based on the position and intensity of scattered light.

Example Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, a parallel beam emitted from a light source 1 is incident on an objective lens 2 eccentrically from the optical axis, and reflected light and scattered light from an object to be measured 3 is received again by the objective lens 2, and a beam splitter 4 The light is reflected by the two-dimensional image sensor 5 and received by the two-dimensional image sensor 5.

In the above configuration, if there is no defect in the object to be measured 3, a reflected light spot is generated on the two-dimensional image sensor at a position corresponding to the displacement of the object to be measured 3, based on the same principle as in the conventional example.

The image processing unit 6 calculates the position of the center of gravity of the light intensity distribution of the reflected light spot, and further converts it into displacement. The relationship between spot position and displacement is measured and memorized in advance.

If the object to be measured 3 has a defect, the light spot irradiated onto the object to be measured 3 will be scattered at that portion. Therefore, a light spot as shown in FIG. 2, for example, is generated on the two-dimensional image sensor 6. Image processing unit 6 from this spot
to separate reflected light and scattered light. The method is as follows. In most cases, defects on the object to be measured 3 are anisotropic, so if two or more light spots are detected in the captured two-dimensional signal, a spot close to a circle is used as the reflected light, Others are judged to be light spots caused by scattering. A determination as to whether a spot is close to a circle is made based on K=-, where the circumference of the spot is divided by 1 area and S is the area. In other words, the smaller K is, the closer it is to a circle.

Next, the displacement is calculated from the position of the center of gravity of the reflected light, and the defect is determined from the position and intensity of the scattered light. The relationship between the position and intensity of this scattered light and the shape and size of the defect is measured and memorized in advance.

Effects of the Invention As described above, in the present invention, reflected light and scattered light from the object to be measured are received by a two-dimensional image sensor, and the image processing section separates and calculates them. Defects can be measured simultaneously without interaction.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a shape measuring device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram thereof, and FIG. 3 is a block diagram of a conventional shape measuring device. 1...Light source, 2...Objective lens, 3.
...Object to be measured, 6...Two-dimensional image sensor,
6... Image processing section.

Claims (1)

[Claims] A light source, a lens installed eccentrically with respect to the optical axis of the light source, a two-dimensional image sensor that receives reflected light and scattered light from the measurement target, and a two-dimensional image sensor that separates the reflected light component and scattered light component from the imaged signal. A shape measuring device that includes an image processing unit that calculates the position and defect of a part.