JPH0617773B2 - A method for determining the actual size of an article to be measured in contour measurement of the article - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement in a method for determining an actual size of an article to be measured in contour measurement of the article.

“Problems to be Solved by Prior Art and Present Invention” There are various types of conventional methods for measuring the contour of an article, but generally, a so-called line sensor having a predetermined number of phototransistors arranged in a line. In many cases, the solid-state image sensor as described above is used.

Therefore, when measuring the article to be measured, it is necessary to focus the image of the article to be measured, that is, the bright and dark parts, on the solid-state imaging device and to handle it by enlarging or reducing it.

This operation of enlarging or reducing the object to be measured can significantly change the actual resolution of the object to be measured with respect to the maximum resolution of the solid-state image sensor, and is an essential and indispensable step in actual measurement.

However, when the object to be measured is magnified or reduced on the solid-state image sensor to form an image, accurate measurement values of the object to be measured often cannot be obtained due to the condition of focusing and the intensity of illumination from the light source. However, in such a case, the electrical signal output from the solid-state imaging device may not be able to obtain a correct one-to-one correspondence with the actual article to be measured.

"Means for Solving the Problem" The present invention has been made in view of the state of the art as described above, and a solid-state image sensor or an object to be measured is a solid-state image sensor of the solid-state image sensor. When a certain distance d1 is relatively moved from a specific point A in the optical axis direction,
The actual magnification value d1 / n1 obtained when the number of dots in the dark portion of the measured object is reduced by n1 is measured at a specific position of the solid-state image sensor, and this is stored in a computer as a magnification table and measured value of the measured object. The solution is to perform a comparison operation with.

[Operation] According to the present invention, a rational magnification table serving as a criterion is set, and a comparison calculation is immediately performed on the measured value of the measured object, so that the measured object is enlarged or reduced. In the measuring method to be performed, it is ensured that the electric signal substantially obtained by the solid-state image pickup device has a correct one-to-one correspondence.

[Examples] Examples of the present invention will be described below, but for the sake of convenience, the description will be given based on the measuring apparatus used for implementing the present invention.

The solid-state image pickup device 1 is preferably a camera generally known as a CCD camera, and a solid-state image pickup device represented by this CCD camera (hereinafter referred to as CCD camera 1).
Is a predetermined number of transistors 1a and a lens 1b arranged in a line
And is located above the DUT 2.

The object to be measured 2 always receives light from the illumination source 3 and the above-mentioned C
The CD camera 1 is made to form the image, that is, the light and dark. CC
Enlargement or reduction of the DUT 2 imaged object 2 can be obtained by moving the CCD camera 1 or the DUT 2 relatively.

The CCD camera 1 outputs a shadow portion where light is not emitted, that is, a dark portion d is Low (0 V), and a portion where light is emitted, that is, a bright portion 1 is output as High (5 V). Then, the output of the CCD camera 1 is transmitted to the T.S.P. An image of the article to be measured 2 is displayed on the V screen 6 in light and dark.

2 and 3 are conceptual diagrams illustrating a procedure for creating a magnification table and the magnification table, which are the subject matter of the present invention.

In FIG. 2, in the optical axis direction of the CCD camera 1, the CCD camera 1 or a certain distance d1 from a certain specific point A, or
When the measured article 2 is relatively moved, the measured article 2
Assuming that the number of dots in the dark part of is decreased by a certain number n1,
The substantial magnification near the specific point A can be regarded as a value of d1 / n1.

Next, the actual magnification value d1 / at the specific point thus obtained
n1 is measured at a specific position of the CCD camera 1. This specific position is the entire length of the CCD camera 1, that is,
It may be determined by the number of all the dots, for example, 5000
If it is a dot, it may be measured at 100 positions at equal intervals within that range.
If it is a D camera, it may be measured at 20 positions at even intervals.

The greater the number of measurement positions, the higher the accuracy, but it is necessary to accept the demet caused by the excessive input data to the computer 5. Therefore, the specific position of the CCD camera 1 for which the substantial magnification value d1 / n1 is obtained should be determined according to the number of dots of the camera, and as described above, corresponds to about 0.2% of all dots. It is preferable to measure at locations and at even intervals.

Thus, the actual magnification value d1 / n1 at the specific position measured on the CCD camera 1 is stored in the computer 5 through the controller 4. FIG. 3 is a conceptual diagram of the magnification table, but it is now assumed that when the object to be measured 2 is enlarged or reduced to form an image on the CCD camera 1, the object to be measured 2 at the position c of the CCD camera 1 is measured. Assuming that the measured value of the dark area is 5 dots per mm, the actual size of the dark area is “1 = 5 dots × 1 mm / 8 dots = 5/8 m”.
It will be calculated and corrected according to the formula of "m", and the output of the electric signal corresponding to the exact distance of the dark part is guaranteed. In addition,
In the figure, 7 is an article mounting table, 8 and 8a are pulse motors, 9 and
9a indicates a pulse motor drive.

"Effect of the Invention" The present invention obtains a substantial magnification value from the data of the starting point of the dark portion of the measured object obtained by the CCD camera as described above, and measures the magnification value at a specific position of the CCD camera, This is a magnification table that is stored in the computer in advance and is used for comparison and calculation with the measured value of the object to be measured, so the actual size of the object to be measured that has undergone the enlargement or reduction process in measurement is accurate. In addition, it will be possible to make quick and easy judgments, and CC
It is assured that the electric signals output by the D camera have a correct one-to-one correspondence.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a measuring device used in the practice of the present invention, FIG. 2 is a conceptual diagram of a procedure for creating a magnification table, FIG. 3 is a conceptual diagram illustrating a magnification table, and FIG. It is a conceptual diagram which showed the whole image of a measurement article. 1 ... CCD camera, 2 ... measurement object, 4 ... controller, 5 ... computer, 6 ... T. V screen, d ... dark area, l ... light area.

Claims (1)

[Claims] 1. An object to be measured is reduced or enlarged relative to its actual size, and a predetermined number of phototransistors arranged in a line capture the object to be measured, and emit different outputs depending on the light and dark formed therein. In the method for measuring the contour of an article using a solid-state image sensor, when the solid-state image sensor or the object to be measured relatively moves a certain distance d1 from a specific point A in the optical axis direction of the solid-state image sensor. , The actual magnification value d1 / n1 obtained when the number of dots in the dark part of the article to be measured decreases by a certain number n1 is measured at a specific position of the solid-state image sensor, and this is stored in a computer as a magnification table and measured. A method for determining an actual size of an article to be measured in contour measurement of the article, which is performed by performing a comparison calculation with a measured value of the article.