JPH10221021A - Size measurement, shape inspection device and inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and method for measuring its shape, size and the like by using a CCD linear image sensor wherein inside and outside diameters can be not only measured, but also an amount of inside and outside eccentricity and shape malfunction can be measured by performing measurement as an object to be measured is rotated. SOLUTION: A light source 2 which outputs flat parallel light on an object to be measured 1, a rotatable table 3 in which a part mounting the object to be measured 1 is constituted of a transparent member, a pulse motor 4 rotating the rotatable table 3, the CCD linear image sensor (CCD sensor) 5 of a detection element projecting the shadow of the object to be measured 1, an arithmetic circuit 6 processing the signal of the CCD sensor 5, and a personal computer 7 controlling a system and performing fetched data processing are comprised. Therefore, with regard to an annular object, not only its inside and outside diameters, but an amount of inside and outside diameter eccentricity and information such as burr on the circumference and lack can be obtained by one time measurement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the shape, dimensions and the like using a CCD linear image sensor. More specifically, the present invention relates to a measuring method capable of measuring dimensions and measuring information on an external shape. The purpose of the development.

[0002]

2. Description of the Related Art In an inspection method using a CCD linear image sensor, for example, in a case where a non-contact appearance inspection of dimensions and shapes is required, such as a rubber product such as a seal, an object to be measured is a belt conveyor or the like. CCD while scanning linearly with
Obtain the line image data using a linear image sensor,
A method of obtaining dimension data by performing image processing on the image is generally used. Also, without using the image processing method in the above method, CC
A method of obtaining the maximum diameter and the minimum diameter from the maximum and minimum widths of the shadow of the object to be measured passing through the D linear image sensor can be considered.

[0003]

First, considering the disadvantages of the first method, if the number of pixels of the sensor is increased to improve the measurement resolution performance, the captured data becomes large and the speed of image processing decreases. . If an attempt is made to increase the image processing speed, the processing apparatus becomes expensive. Next, considering the shortcomings of the second method, the obtained data cannot be understood from the detailed information only by the maximum and minimum widths of the shadow of the measured object passing through the CCD linear image sensor. When the scanning direction of the conveyor is the one axis direction, the failure detection of the measured object is not complete. (See FIG. 8) In the present invention, in a method of measuring the shape, dimensions, and the like using a CCD linear image sensor, the measurement is performed while rotating an object to be measured, for example, such as a rubber seal. It is an object of the present invention to develop a measurement method capable of obtaining not only the inner and outer diameters of an annular object but also information such as the eccentricity of the inner and outer diameters and burrs and chips on the periphery in one measurement.

[0004]

In a method of measuring the shape, dimensions, and the like using a CCD linear image sensor, the measurement is performed while rotating an object to be measured. Provided is a measuring device and a measuring method which can obtain not only the inner and outer diameters of an annular object but also information such as the eccentricity of the inner and outer diameters and burrs and chips on the periphery in one measurement. FIG. 1 shows a configuration of the measuring device. A light source (2) for outputting plane-parallel light to a measuring object (1) and a portion on which the measuring object (1) is mounted are transparent members. A rotary table (3) configured, a pulse motor (4) for rotating the rotary table (3), and a CCD linear image sensor (5, hereinafter referred to as a CCD sensor) of a detection element for projecting a shadow of the measurement target (1). And an arithmetic circuit (6) for processing signals from the CCD sensor (5).
And a personal computer (7, hereinafter referred to as a personal computer) that controls the system and processes the captured data.

[0005] As a measuring method using the above-mentioned measuring device, there is a measuring object (1) placed on a rotary table (3).
Is irradiated with parallel light from a light source (2), and its rotary table (3) is rotated by a pulse motor (4) synchronized with a reset pulse of the CCD sensor (5). An analog voltage signal that is changed by projecting a shadow of the object to be measured (1) is output for each of the determined feed angles described in 4), and the analog voltage signal is secondarily differentiated using an arithmetic circuit (6). Is obtained, a signal having information on only the edge position of the outer shape of the object to be measured (1) is obtained, and the signal position is synchronized by synchronizing the edge signal with the driving pulse of the CCD sensor (5). It is characterized in that it is made to correspond to the pixel number of the CCD sensor (5), and only this pixel number data is taken into the memory of the personal computer (7) to measure the shape.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The operation of this system and the principle of measurement will be described below with reference to FIG. First, a light source (2) irradiates a parallel light to a measurement object (1) placed on a rotary table (3), and the pulse motor (4) synchronizes the table with a reset pulse of a CCD sensor (5). To rotate. During this time, the CCD sensor (5) outputs an analog voltage signal that is changed by projecting the shadow of the measuring object (1) at each fixed feed angle of the pulse motor (5). Next, the analog voltage signal is secondarily differentiated using an arithmetic circuit (6), and a zero-cross point of the signal is obtained, whereby a signal having only information on the edge position of the outer shape of the object to be measured (1) is obtained. can get. Then, by synchronizing the edge signal with the drive pulse of the CCD sensor (5), this signal position is made to correspond to the pixel number of the CCD sensor (5), and only this pixel number data is taken into the memory of the personal computer (7).

By this processing, conventionally, all of the analog sensor analog voltage output signals are A / D converted and taken into the personal computer (7). Since the processing is replaced with the fetching processing, the processing speed is greatly improved. This signal processing is performed in parallel with the rotation of the pulse motor (4). Since the processing has been completed by the next data take-in angle, measurement is performed while sending edge position information to the memory of the personal computer (7). Can improve the processing speed of the system. FIG. 2 shows the signal processing of the CCD sensor.

Next, as shown in FIG. 3, it is assumed that the center of rotation of the rotary table (3) is the origin of the XY plane on the table, and that the pixels of the CCD sensor (5) are arranged on the X axis. Then, the pixel data of the edge of the measuring object (1) projected on the CCD sensor (5) can be expressed by the value of the X coordinate. (Data of the distance from the rotation center) Then, by taking sin θ and cos θ at each angle of this data, this data is converted into the XY coordinate system on the rotation table (3), and the personal computer (7) The center coordinates of the object to be measured (1) are obtained by performing arithmetic processing, and the inner and outer diameter dimensions,
Data such as the amount of eccentricity of the inner and outer diameters, the roundness, burrs, and the presence or absence of chipping can be obtained. FIG. 4 shows a flowchart of the present system.

FIG. 5 shows a state of measurement using the present system. The size of the measurement target (1) that can be measured by the present system is limited to the length L2 of the range where the pixels of the CCD sensor (5) exist.
A large object can be measured by changing the distance L1 to the first pixel of the sensor or by inserting a lens between the object (1) and the CCD sensor (5).

[0010] In this system, the CCD from the center of rotation
Since the distance L1 to the first pixel of the sensor is known and the data taken into the personal computer (7) is also angle-corresponding, the position where the object to be measured (1) is placed should be at the rotary table as long as it crosses the rotation center. (5) Any position above may be used.
Furthermore, by the calculation program after the data is taken,
The shape of the measurement object (1) can be any shape such as a ring, a disk, a polygon, and any other shape.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In this system, since the external shape data of an object to be measured (1) is converted into values of XY coordinates on a rotary table (3), the circumference of an object having an unstable shape such as an O-ring. Also,
It can be easily obtained by calculation on the personal computer (7). (See FIG. 6) It is also possible to measure dimensions such as R1 and L3 of a complicated shape such as a rubber gasket shown in FIG.

[0012]

According to the above configuration, the following excellent effects can be obtained. In the present invention, the object to be measured (1)
By measuring the shape, dimensions, and the like with the CCD linear image sensor (5) while rotating the lens, not only the inner and outer diameters of the annular object but also the eccentricity of the inner and outer diameters and burrs on the periphery are measured.
Many information such as chipping can be obtained by one measurement. Further, in the present system, the perimeter and the like of an object having an unstable shape can be easily obtained by calculation using a personal computer (7), and the dimensions of a complicated object can be accurately measured.

[Brief description of the drawings]

FIG. 1 shows a configuration of a system of the present invention.

FIG. 2 shows how signal processing is performed by a CCD sensor.

FIG. 3 is a conceptual diagram of measurement data-coordinate conversion according to the present invention.

FIG. 4 shows a flowchart of the system of the present invention.

FIG. 5 shows how measurements are made using the system of the present invention.

FIG. 6 shows an embodiment of the measurement object of the present invention.

FIG. 7 shows an embodiment of the measurement object of the present invention.

FIG. 8 shows a conventional measurement method without using the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Measurement object 2 Light source 3 Rotary table 4 Pulse motor 5 CCD linear image sensor (CCD sensor) 6 Arithmetic circuit 7 Personal computer (PC)

Claims (2)

[Claims] 1. An inspection apparatus for measuring the shape, dimensions and the like using a CCD linear image sensor, wherein a light source for outputting plane-parallel light to the object to be measured and a portion on which the object to be measured is placed are transparent. A rotary table composed of members, a pulse motor for rotating the rotary table, a CCD linear image sensor (hereinafter referred to as a CCD sensor) as a detecting element for projecting a shadow of a measurement object, and an operation for processing signals from the CCD sensor A dimensional measurement and shape inspection device comprising a circuit and a personal computer (hereinafter referred to as a personal computer) for controlling the system and processing the captured data. 2. An inspection method for measuring the shape, dimensions and the like using a CCD linear image sensor, wherein an object to be measured placed on a rotary table is irradiated with parallel light from a light source. The CCD sensor is rotated by a pulse motor synchronized with the reset pulse, and the CCD sensor outputs an analog voltage signal that is changed by projecting the shadow of the object to be measured at every fixed feed angle of the motor, and calculates this analog voltage signal The circuit is secondarily differentiated using a circuit to obtain a zero-cross point of the signal, and a signal having only information on an edge position of the outer shape of the object to be measured is obtained. The edge signal is synchronized with a driving pulse of the CCD sensor. This signal position is made to correspond to the pixel number of the CCD sensor, and only this pixel number data is taken into the memory of the personal computer to measure the shape. Dimension measurement and shape inspection method.