JPS638404B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for measuring the dimensions of an object in a non-contact manner using optical means.

A conventional device of this type is shown in FIG. In the figure, 1 is a target object, 2 is a camera including a lens that images the target object 1 and a detector that converts the image into an electrical signal, 3 is a lens that images the target object 1, and 4 is an image captured by the lens 3. A one-dimensional or two-dimensional detector (in the following explanation, a two-dimensional detector is used as a representative) that converts the signal into an electrical signal. 5 is a monitor that receives the output of the two-dimensional detector 4 and displays an image, and 6 is a processing device. It is a device.

Next, the operation will be explained. When the target object 1 is imaged by the camera 2, an image 1a as shown in FIG. 2 is obtained from the two-dimensional detector 4 on the monitor 5. At this time, the dimension b of the image and the actual dimension w of the target object 1 have a relationship expressed by the following equation (1).

w=m・α・b...(1) Here, m is the magnification of the optical system, and the distance L from the lens 3 to the target object 1, and the distance l from the lens 3 to the two-dimensional detector 3 of the camera 2. It is determined by m=l/L...(2). Moreover, if the focal length f of the lens 3 is expressed, m=f/L−f (3). Generally, the focal length f is fixed at a constant value, so if L is kept at a constant value, the magnification m of the optical system will be a value that does not change. Further, α is an electrical magnification determined by the camera 2 and the monitor 5, and is generally a constant value. Therefore, the magnification m of the optical system and the electrical magnification α are calculated or measured in advance, and the size b of the image obtained on the monitor 5 is determined.
The dimension w of the target object 1 can be obtained by measuring and calculating the above equation (1) using the processing device 6.
The measurement of the image dimension b is carried out using a commonly used video signal processing technique, and an appropriate lighting device is also used to facilitate the separation of the image of the target object 1 from the background. .

Since the conventional dimension measuring device is configured as described above, it is necessary to calculate or measure the magnification m of the optical system in advance, and the magnification m of the optical system is
It is necessary to keep the distance L from the target object to the lens constant, and even if the thickness of the target object fluctuates, the target object vibrates, or even if the target object is tilted, it cannot be detected. There were drawbacks such as the inability to measure dimensions accurately.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and involves forming bright and dark areas on both sides of a target object using a suitable light projecting means, and imaging the bright and dark areas and the target object. Since the coordinates of both ends of the target object in the dimension measurement direction can be calculated, dimensions can be measured without being affected by vibrations, thickness changes, and inclinations of the target object, and if necessary, it is possible to measure the variable values of variable elements. The purpose is to provide a measuring device.

An embodiment of the present invention will be described below in Figures 3 to 5.
The diagram will be explained. In Figure 3, 7 is the fourth
As shown in the figure, a light projecting device is provided such that a divergence point P is located on the y-axis, which is the optical axis of the camera 2, and 8 is a table on which the target object 1 is placed. FIG. 4 is a schematic diagram showing the operation of the present invention and the arrangement of the optical system, where A is the light receiving surface of the two-dimensional detector 4. Fig. 5 shows the images of the target object 1 and the table 8 formed on the monitor 5 of the two-dimensional detector 4 to explain the operation of the present invention; is an image of the bright part of the table 8 illuminated by the projector 7, d and f is an image of the dark part of the table 8 that is in the shadow of the target object 1. The image shows the bright part of the image.

Next, the operation of the device according to the present invention will be explained.
In FIG. 3, the process until the target object 1 is imaged by the camera 2 and the image of the target object 1 is obtained on the monitor 5 is as described in the description of the conventional apparatus. However, in this invention, as shown in FIG. 4, the light projecting device 7 has its divergence point P located on the axis in the width direction of the camera 2, and projects from the second principal point position 0 of the lens 3 in the height direction. Divergence point P of optical device 7
is provided on the target object 1 side, so that the target object 1 created by the illumination of the projector 1 on the table 8
The shadow part is also imaged by the camera 2 and displayed on the monitor 5. To explain in more detail with reference to FIGS. 4 and 5, the second principal point position 0 of the lens 3 and the illumination light divergence point position P of the light projector 7 with respect to the target object 1 have the same optical axis in the width direction on the table 8. They are arranged so as to intersect at right angles, and the intersection point is O', and the distance Y _OO ' between points O and O' and the distance Y _OP between points O and P are determined appropriately. The illumination light diverging from point P illuminates target object 1 and table 8, but due to the corresponding shadow between point Q and point R of target object 1 when viewed on the surface of table 8, the illumination light diverges from point T to point N. It gets dark until then. On the other hand, the camera 2 has a field of view on the surface of the table 8 from the point S to the point Z, and images the target object 1 from the point Q to the point R. In other words, the area corresponding to point U to V on the surface of table 8 appears bright, corresponding to E in Fig. 5, and in the other visual field areas, points S to U and point V to Z on table 8 appear bright. Imaging. In this imaged portion, points T to U and points V to N included in the shadow portion of the target object 1 described above appear dark and correspond to d and f in FIG. 5, respectively. Further, the portions from point S to point T and point from point N to point Z, which are imaged on the surface of the remaining table 8, appear bright and correspond to the portions C and G in FIG. As described above, all images obtained on the monitor 5 as shown in FIG. 5 can be considered as objects on the surface of the table 8. Therefore, the dimensions of the image on the surface of the table 8, for example the distance from O' to point U, X _O ' _U , can be calculated from equation (1) mentioned in the explanation of the conventional device: X _O ' _U = m・α・b _O ′ _U ......(4) is obtained, and m is obtained by subtracting L in equation (2) or (3).
Since Y _OO ′ becomes a constant value, the electrical magnification α is a constant value set in advance, and b _O ′ _U is the distance between the images O′U on the monitor 5, by measuring b _O ′ _U
X _O ′ _U is required. Here, b _O ′ _U is measured using an image processing technique commonly used in the processing device 6.

Similarly, the distance between each point on the surface of the table 8 is calculated from the image size of the monitor 5. Point Q of target object 1 is the straight line connecting point O and point U
The equation of each straight line, which is the intersection of the straight line y _T connecting y _U and points P and T, with O as the origin, is as shown in Figure 4, if the directions of the arrows are the x-axis and y-axis directions, respectively. It is given by y _Ui =Y _OO ′/X _O ′ _U X _i ……(5) y _Ti =Y _OO ′−Y _OP /X _O ′ _T X _i −Y _OP ……(6). _From these equations _{( 5} ) _{and ( 6} ) _, if _i is set as Q, _then ), the Q(X _Q , Y _Q ) coordinates are obtained. Here, K ₁ =X _OO ′/X _O ′ _U ……(9) K ₂ =Y _OO ′−Y _OP /X _O ′ _T ……(10).

Y _OO ′ and Y _OP for determining X _Q and Y _Q are constants determined by the configuration of the device, and X _{O ′ U} and X _O ′ _T are the image dimensions of the monitor 5, for example, the dimension b on line A in Figure 5. It can be calculated from _O ′ _U and b _O ′ _T as explained in equation (4) above. Similarly, the R (X _R , Y _R ) coordinates of target object 1 are the straight line y _V
Since _{it is the intersection of and} y _N , y _Vi = −Y _{OO ′} ／X _{O ′ V 12 ) Accordingly , _ _ _ _ _ _ _ _ _} ...(13) K ₂ = Y _OO ′−Y _OP /X _O ′ _N ...(14) where X _O ′ _U , X _O ′ _N are the image dimensions of monitor 5 b _O ′ _V , b It can be calculated by measuring _O ′ _N.

As described above, Q (X _Q , Y _Q ) and R (X _R ,
The coordinates of each point in Y _R ) are determined.

The dimension W in the width direction of the target object 1 is determined by considering the inclination of the target object: W=√(| _Q |+| _R |) ² +(| _Q |-| _R
|) ² ...(15) It can be calculated as follows.

Also, the distance L between the target object 1 and the point O of the lens 3 is obtained as L=|Y _Q |+|Y _R |/2 ...(16), and the inclination △ of the target object 1 is △=|Y _Q ｜−｜Y _R ｜ ...(17) is obtained as follows.

These calculations are performed by the processing device 6.

Here, to provide a supplementary explanation of the configuration of the processing device 6, the processing device 6 includes a dimension display section or a dimension output section that displays or outputs the calculation result of the above-mentioned equation (15), and a dimension output section that displays the calculation result of the equation (17). A tilt amount display unit is provided to display a quantitative value of the tilt Δ of the target object 1.

Therefore, the inclination of the target object 1 can be corrected by a separate control means depending on the value of the inclination Δ.

In the above embodiment, the calculation formula was developed using the second king point 0 of the lens 3 as the origin, but this can be arbitrarily selected.

As in the embodiment, if the divergence point P of the light projecting device 7 is located on the main axis of the lens 3, the calculation becomes easy, the calculation time is shortened, and the configuration of the processing device 6 is simplified. .

In the embodiment, the electrical video signal from the two-dimensional detector 4 is inputted to the processing device 6 via the monitor 5, but the two-dimensional detector 4 and the processing device 6 may be directly connected.

As described above, according to the present invention, by appropriately arranging the light projection means that forms bright and dark areas on both sides of the target object and the imaging means that images the target object and the bright and dark areas, From the image dimensions of this shadow, the dimensions of the target object can be found in terms of coordinates, and the effect is that the dimensions can be measured regardless of the tilt, vibration, or thickness change of the target object.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the structure of a conventional device, FIG. 2 is a diagram of a monitor for explaining the operation of the conventional device,
FIG. 3 is a diagram showing an embodiment of the dimension measuring device according to the present invention, and FIGS. 4 and 5 are diagrams showing the optical system arrangement and monitor images for explaining the operation of the embodiment of the device according to the present invention. be. In the figure, 1 is a target object, 2 is a camera, 3 is a lens, 4 is a two-dimensional detector, 5 is a monitor, 6 is a processing device, and 7 is a light projector. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A light projecting means that projects light onto a target object and creates a shadow of the target object on both sides of the background of the target object, an optical lens that forms an image of the target object and the background, and an electrical signal corresponding to the optical image formed by this optical lens. an imaging means having a photoelectric detector for outputting, determining the coordinates of the edge in the width direction of the target object based on the edge signal of the shadow of the target object imaged by the imaging means and the edge signal of the target object; A dimension measuring device comprising a processing device that calculates the dimensions of the target object based on the coordinates.