JPH0618223A - Optical measuring method of remote object - Google Patents

Abstract

PURPOSE:To inclination, irregularities, and the like of an object by determining the center of gravity of imaging light point on an imaging surface and measuring positional shift of the center of gravity. CONSTITUTION:An object W is placed at a horizontal reference position and light is projected thereon from a light projector 2. A camera 3 picks up an image of the object W and retrieves the center of gravity G on an imaging surface thus determining a reference position. When the object moves to a position Wa inclining by an angle theta, the surface T irradiated with the light projector 2 moves to Ta and the center of gravity G of the imaging surface S moves to C. Assuming the moving distance of the center of gravity as (c), elevating distance (h) of measuring point is measured. Assuming the central position of lens is A, and the positions corresponding to the center of gravity G on the irradiated surfaces T and Ta are F and D, (c) can be determined through measurement because the length m:k is known. Since <delta <beta can be calculated, each dimension of DELTAABF can be calculated. Furthermore, since <alpha is known, one side BF and one angle <ABF of DELTADBF can be calculated and, thereby, the sides DF, DB and the height (h) can be calculated. The measurement is repeated while moving the object Wa thus discriminating inclination or irregularities and determining the degree of irregularities.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical measuring method for photographing a remote object with a camera and measuring unevenness, thickness, position, inclination or vibration of the surface of the object.

[0002]

2. Description of the Related Art As a method for surely measuring the minute dimension of the unevenness of the remote measuring object in a non-contact manner, a method of measuring an electric value with a non-contact needle is widely known. There is also a measurement method using the Toppler effect with ultrasonic waves. Alternatively, some methods of measuring with light have been attempted.

[0003]

However, the first non-contact needle type electric value measuring method is not general because it has a high measuring accuracy but is high in cost. The second Toppler effect method has problems such as poor accuracy and high cost. A strobe lamp or the like is generally used to measure the number of revolutions, but it is difficult to use it outdoors or to measure at a low speed, and there is a non-contact method that uses reflected light to measure the frequency. However, there are problems that the place to measure is limited and that it is not suitable for the measurement of minute vibrations.

The present invention has been made in view of the above points, and the light emitted from an object to be measured is imaged by a CCD camera, preferably a PSD (position sensing device) camera, and an imaged light spot on an image pickup screen. An object of the present invention is to provide a novel measuring method for measuring the static state of the target object such as unevenness, inclination, thickness, position and the like, and dynamic state such as the number of vibrations and rotations from the displacement of the center of gravity of the object.

[0005]

The optical measuring method for a remote object according to the first aspect of the present invention for achieving the above object is to illuminate an object to be measured with a projector, photograph the object, and measure the center of gravity of the imaged light spot. From the distance between the reference position and the center of gravity set in advance on the imaging surface, the static state of the measurement object such as unevenness, inclination, thickness and position of the measurement object, and the vibration (amplitude and frequency) rotation speed etc. The dynamic state of the measuring object is measured.

A second aspect of the invention is to irradiate the surface to be measured with a light beam from an oblique direction and to capture an image from a direction substantially perpendicular to the surface. On the contrary, a light beam is irradiated from a direction substantially perpendicular to the surface to be measured, and images are taken from two or more diagonal positions at ± equal distances on the XY axis with the irradiation light beam as the center.

In a fourth aspect of the invention, the light source uses a front-back, left-right symmetrical laser beam with one point as the center.

In a fifth aspect of the invention, the frequency measurement is calculated from the measurement value of the periodicity of the uneven height variation of the moving measurement target point.

Further, in a sixth aspect of the present invention, an object to be measured is provided with a light-emitting body, the light-emitting body is photographed by a camera, a point center of gravity of imaged light is obtained, and measurement is performed from a distance between a reference position and a center of gravity set in advance on an image pickup surface. The position variation of the object such as vibration and rotation is measured.

According to a seventh aspect of the invention, in the first and sixth aspects of the invention, the camera has means for converting a change in the light quantity of the image pickup surface into a change in the electric quantity, and the converted electric quantity is converted into X-axis and Y-axis. The position of the maximum value is measured to find the center of gravity.

An eighth aspect of the invention is to measure the distances from the upper, lower, left, and right object surfaces of the object to be measured to the object at the same time, and measure the positional variation, thickness, unevenness, and vibration of the object.

A ninth aspect of the present invention is intended to measure the center of gravity of an image pickup light point of light on two fixed points on the axis of an object to be measured and measure the "twist" of the shaft or the transmitted power from the positional deviation. .

[0013]

The measurement of unevenness, inclination, vibration and the like of the object to be measured is performed by obtaining the position of the center of gravity of the imaged light spot, measuring the movement of the center of gravity of the image pickup surface due to the movement of the object, and calculating based on this.

[0014]

1 and 2 show a first embodiment of the present invention. A measuring device 1 for carrying out the method of the present invention comprises a projector 2 and a camera 3.
The camera 3 is a CCD camera or the above-mentioned PSD camera, and uses a camera equipped with a measuring unit 4 for obtaining the center of gravity of the imaged light spot on the imaged surface. The projector 2 is provided with a laser beam, an LED, and other light emitters such as helium neon. The laser beam may be a point beam, but is preferably a front-back and left-right symmetrical type parallel beam centered on one point.

When measuring the unevenness and inclination of the object to be measured by the measuring device 1, a laser beam or the like is used to measure the object W.
The center of gravity of the imaged light spot is obtained by measuring the distance between the reference position and the center of gravity set in advance on the image pickup surface. First, the method of obtaining the center of gravity of the imaged light spot is described. explain.

FIG. 3 shows a procedure for obtaining the center of gravity of an imaged light spot by a CCD camera. The CCD camera is an image pickup plate in which a large number of transfer electrodes (pixels) are vertically and horizontally arranged on a semiconductor substrate. is there. It is assumed that the scanning lines in this CCD camera are horizontally scanned and then sequentially moved downward from the upper side, and the light spots formed on the light receiving surface 5, that is, the pixels are assumed to be circular. The image-integrated waveform length on the scanning line 6a that first contacts the light-receiving surface 5 is 0, and becomes longer as it moves downward, and the scanning line 6 passing through the center.
It becomes the maximum in b, then decreases gradually, and the scan line 6
It becomes 0 in c. Therefore, it is clear that the position of the center of gravity G is on the scanning line 6b where the video waveform is the maximum, and this scanning line is searched and the distance from the reference line X is stored as y.

The position of the center of gravity G in the lateral direction is determined by the same method as in the sub-direction. Alternatively, it can be obtained by dividing the time between the first and last pixels 6d and be receiving the video signal in the scanning line 6b forming the longest video waveform into two. The distance from the vertical axis Y is stored as x. That is, the position of the center of gravity G is stored as an xy value in XY coordinates.

In this case, in the ordinary CCD camera, when calculating the above x and y values, the light receiving amount (voltage) of the light receiving pixel.
Need to be integrated for each column and row of the pixel, which is troublesome and inconvenient in terms of time, cost and accuracy. On the other hand, when using the PSD camera, it is convenient because the amount of light received by each pixel is immediately converted into an analog signal for each column and row and stored. In particular, it is preferable for a front-and-back, left-right symmetrical laser beam having a large light amount in the central portion as a light source. Therefore, in the present invention, it is preferable to use this PSD camera, but the present invention is not limited to this, and a conventional CCD camera may be used for imaging.

Next, a concrete example of the method for measuring the inclination and unevenness of a remote object according to the present invention will be described with reference to FIGS. This embodiment shows an example in which the light projector 2 is arranged obliquely above a measurement object (hereinafter simply referred to as an object) W, and the photographing camera 3 is arranged above the measurement object surface at a right angle. The light source of the light projector 2 irradiates the measurement target surface W with a laser beam. In the figure, L is a lens,
S indicates an image pickup surface.

First, the object W is placed at a horizontal reference position (the object at this position is referred to as a reference object). Then, the light emitted from the light projector 2 is emitted vertically downward of the camera 3, and an image is picked up by the camera 3, the center of gravity G is searched for on the image pickup surface S according to the above procedure, and this position is set as a reference value. Next, it is assumed that the object moves to a position Wa that is inclined by the angle θ (the object at this position is referred to as a measurement object). As a result, the irradiation surface T from the light projector 2 moves to Ta, and accordingly, the gravity center position G of the imaging surface S moves to C. The moving distance of the center of gravity is defined as c, and the rising distance h of the irradiation surface, that is, the measurement point is measured. The measurement procedure is as follows.

In FIG. 2, ΔAGC and ΔABF are similar. However, A is the center position of the lens, and F and D are positions facing the center of gravity G on the irradiation surfaces T and Ta. The length m: k is a known number, and c is known from the measurement. △
Since c and k are known numbers in AGC, ∠δ,
∠β can be calculated. From this, each dimension of ΔABF can be calculated. Also, ∠α is a known angle. Therefore, in ΔDBF, since one side BF and ∠ABF are known from the calculation, each side DF and DB can be calculated. From this, DH, or height h, can be calculated. By repeating this measurement procedure while moving the object Wa to be measured, it is possible to determine whether the inclination angle or the unevenness of the object Wa and also to measure the height of the unevenness.

Next, FIG. 4 and FIG. 5 show other measuring procedures by the measuring device 1. That is, the projector 2 is the reference object W
An example in which the camera 3 is positioned vertically upward with respect to and the camera 3 is positioned at a predetermined angle αa is shown. Also in this case, similarly to the previous example, first, the object W is placed at the horizontal reference position, the light projected from the light projector 2 is imaged by the camera 3, and the center of gravity of the light spot group on the imaging surface is obtained. This position is designated as K. Note that J indicates the position of the object W with respect to the center of gravity K on the irradiation surface. Next, the irradiation position J moves to O by moving (tilting) the object W to the position of the measurement object Wa that is inclined by the angle θ, and the center of gravity position on the imaging surface S moves to M. The moving distance of this position of the center of gravity is k. In FIG. 5, ΔAKM and ΔAJP are similar triangles, and n is a known value.
Therefore, in the right triangle ANO, since the length n of one side AN and ∠NAO (αa−δa) are known, the length of the line segment k, that is, the height h can be calculated. This height variation can be easily measured by moving the measurement object Wa and repeating the measurement as in the previous example, whether the object is inclined or uneven.

When the surface of the object to be measured has irregularities, a single measuring device may cause a blind spot in measuring the depth of the concave portion, resulting in an error. As a means for solving this, it is preferable to arrange a plurality of cameras around the projector 2. FIG. 6 shows an example thereof, in which the measuring device 1a includes a projector 2 which irradiates a surface to be measured at right angles and four cameras 3a which are arranged at equal distances on the XY axes around the irradiation light beam.
3b, 3c, 3d. With this structure, since measurement is performed from four directions at the same time, it is possible to prevent an error in measurement.

The same applies to the case of the first embodiment, but when this measurement height variation has a constant cycle, it is used as a pitch measurement, and when the object is a rotating body, the height variation This is measured as the frequency (vibration) by measuring the periodicity.

Next, an actual measuring procedure using the above-described measuring apparatus according to the present invention will be described with reference to the embodiments shown in FIG. FIG. 7 shows a frequency measuring procedure of a round bar Wb having one end fixed or both end shafts that vibrate or rotate. As described above, the measuring device 1 irradiates the rotating measurement target Wb from the light projector 2 and images the irradiation surface with the camera 3. In this case, the camera 3 is preferably positioned at right angles to the axis of rotation. For the measurement, measure the standard round bar without shaking beforehand,
Based on this. Then, in the measurement, the height of the shake is measured from the moving distance of the position of the center of gravity of the light spot on the imaging surface based on the movement of the projected light spot due to the shake as described above. Although not shown, the camera 3 and the light projector 2 as a set can be moved along the axis of the round bar W to measure the entire round bar.

Next, FIG. 8 shows a measuring procedure of the unevenness of the measuring object Wc. In this case as well, the camera 3 is similarly placed at a right angle to the horizontal plane including the movement axis of the object Wc, the projector 2 is arranged so as to be inclined, and the object Wc is moved and measured. As a result, the height of the unevenness of each part can be measured in the same manner as described above. In the figure, only one set of camera and floodlight is shown.
By providing a plurality of sets, it is possible to measure many surfaces at the same time. Also, if the measurement in the X-axis direction is completed in the figure, Y
By performing the measurement in the axial direction, the unevenness on the entire surface can be measured. In this case, the light projecting axis of the projector 2 is at right angles to the horizontal plane, and the cameras are arranged in four diagonal directions at ± equal distances on the front, rear, left, and right, that is, on the X axis and the Y axis with respect to this optical axis, and images are taken. In this case, there is no blind spot in the measurement, which is convenient.

Next, FIG. 9 shows a procedure for measuring the thickness of the belt-like object. In this case, the measuring devices 1 and 1 are arranged above and below the object Wd to be measured. 2a and 2b are projectors, 3a and 3b
Indicates a camera. In this case, the upper and lower cameras are preferably arranged at right angles to the object Wd. According to this measuring method, even if the sending out of the object Wd meanders up and down, it is possible to perform accurate and continuous measurement by canceling the plus and minus values of the upper and lower measured values. Therefore, even when the object is a corrugated plate, it is possible to reliably measure the meat pressure. When the width of the object is wide, a plurality of sets of measuring devices may be provided. In this case, it is possible to measure the position variation, unevenness, vibration, etc. of the object at the same time.

Next, FIG. 10 shows a measuring device 1b in which a light source is incorporated in a PDS camera. BS is a half mirror, F is a filter, S is an image pickup surface, L is a lens, and LP is a light source.
The illustrated example shows an example in which the measurement target We is a mirror and the verticality of its attachment is measured. According to this measuring device, when the mirror We is set to be vertical, the center of gravity of the light spot on the image pickup surface of the light reflected from the mirror We is located at the center of the image pickup surface S, but the mirror tilts. When it is present, the reflected light moves from the center of the image pickup surface S. Therefore, the tilt angle can be measured from the movement amount.

Next, FIG. 11 shows an application of the device of the present invention to a measuring device for measuring the quality of the lens group LR of a general camera according to the present invention. This lens measuring device 1b includes one projector 2 and one projector 2. It consists of individual cameras 3f and 3g. The lens group LR includes a half mirror BS and lenses L1, L2, L3.
Combining with and. With respect to this lens group LR, PSD cameras 3f and 3g are respectively installed at a film installation position and an image viewing window on the upper side, and a projector 2 is arranged in front of the lens group LR so that the image pickup surfaces of both cameras 3f and 3g. The positional deviation of the center of gravity of the light spot is measured, and when the positional deviation occurs, the lenses L1, L2 and L3 are adjusted.

Next, FIG. 12 shows the procedure for measuring the shake of the rotating body. An example of measuring the shake of a wheel of an automobile as the rotating disk We by the measuring device 1 of the present invention is shown. Light from the projector 2 is applied to the wheel We and the reflected light from the wheel We based on the shake of the wheel We is imaged. And camera 3
The shake of the position of the center of gravity of the light spot on the image pickup surface is measured in the above manner. This applies not only to automobiles, but to all measurements of perpendicularity to the axis of a disk attached to the axis of rotation.

Next, FIG. 13 is different from each of the above-mentioned embodiments.
An example is shown in which the projector 2a is attached to an object whose shake is to be measured, for example, a building, and the shake is measured. That is, the measuring device 1d of the present embodiment is composed of the projector 2a attached to the bridge Wf as an object and the camera 3 provided apart from this. The light emitted from the light projector 2a is obtained by determining the center of gravity of the light spot on the image pickup surface of the camera 3, and the shake of the light projector 2 is measured as the shake of the bridge Wf (including twist and the like together with vibration). Projector 2a in this case
Can be considered as a projection light point on the object described above, and the action thereof is the same as in each of the examples described above, and a description thereof will be omitted. Furthermore, instead of a floodlight, attach a reflector such as a mirror,
You may project from another and measure the reflected light. When a light projector is attached to a moving object, it is possible to measure the moving speed instantly. (Figure 16)

Next, FIG. 14 shows an example in which the measuring object itself is a light emitting body (or a light emitting portion), and the quality of the position of the light emitting portion is measured. That is, the measurement device 1e includes the camera 3 and the light emitting unit LS of the object Wg. In the illustrated example, an engine plug is shown as an object, and the spark generation position thereof is measured. The measuring procedure is the same as that in FIG. 13, and the description thereof will be omitted.

Next, FIG. 15 shows a measuring procedure of the "twist" of the shaft when the object to be measured is the shaft (or the rod) and a rotational load is applied to one end thereof. Two measuring points AB are set on the axis, the center of gravity of the light spot is measured simultaneously by two measuring devices, and the twist is calculated from the "deviation". If the strength of the shaft is known, the load can also be calculated. .

[0034]

As described above, the present invention is provided with a light projector and a camera, illuminates an object by light projection from the light projector, images the object with the camera, obtains the center of gravity of the imaging light point on the imaging surface, and previously Since the surface condition of the measuring object is measured from the moving distance between the reference position and the moving position of the center of gravity set on the image pickup surface, the unevenness, inclination, thickness, position, etc. of the object can be measured in a non-contact manner with respect to the object. It is possible to effectively measure not only the dynamic state but also the dynamic state such as the vibration frequency, its amplitude, and the rotation speed, and the measurement can be performed quickly and accurately.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first measuring procedure by a measuring apparatus to which the method of the present invention is applied.

FIG. 2 is an explanatory diagram of a calculation procedure in FIG.

FIG. 3 is an explanatory diagram of a second measurement procedure by the measurement device.

FIG. 4 is an explanatory diagram of a calculation procedure in FIG.

FIG. 5 is an explanatory diagram of how to obtain a center of gravity of a light spot on an imaging surface.

FIG. 6 is an explanatory diagram of a third measuring procedure by the measuring device including a plurality of cameras.

FIG. 7 is an explanatory diagram of a vibration measurement procedure of a rotating body by the measuring device of the present invention.

FIG. 8 is an explanatory diagram of a method for measuring the surface state of an object by the measuring device of the present invention.

FIG. 9 is an explanatory view of the procedure for measuring the thickness of the plate-shaped member by the measuring device of the present invention.

FIG. 10 is an explanatory diagram of an inspection procedure of a mounting state of a mirror by the measuring device of the present invention.

FIG. 11 is an explanatory diagram of an optical axis measurement procedure of a lens group by the measuring device of the present invention.

FIG. 12 is an explanatory view of a procedure for measuring the shake of the rotating plate by the measuring device of the present invention.

FIG. 13 is an explanatory view of a procedure for measuring shake of a structure by the measuring apparatus of the present invention.

FIG. 14 is an explanatory view of the procedure for measuring the positional deviation of the light emitting unit by the measuring device of the present invention.

FIG. 15 is a diagram for explaining the procedure for measuring the twist or the applied load of the rotating body or the structure by the measuring device of the present invention.

FIG. 16 is a diagram for explaining the speed measurement procedure of a moving object according to the measurement position of the present invention.

[Explanation of symbols]

 1 Measuring Device 1a Measuring Device 1b Measuring Device 1c Measuring Device 1d Measuring Device 1e Measuring Device 2 Projector 3 Camera G Light Point Center of Gravity Reference Position S Imaging Surface W Reference Target Wa Measurement Target

Claims (9)

[Claims] 1. An object to be measured is illuminated by a light projector, and this is photographed by a camera to obtain the center of gravity of an imaged light spot, and the unevenness and inclination of the object to be measured are determined from the distance between the reference position and the center of gravity set in advance on the imaging surface. Optics of remote objects characterized by measuring the static state of the measuring object such as thickness, thickness and position (distance from a fixed position) and the dynamic state of the measuring object such as vibration (amplitude and frequency) rotation. Measurement method. 2. The optical measuring method for a remote object according to claim 1, wherein the surface to be measured is irradiated with a light beam from an oblique direction and the image is picked up from a direction substantially perpendicular to the surface. 3. A light beam is radiated from a direction substantially perpendicular to a surface to be measured, and images are taken from two or more diagonal positions at ± equal distances on the XY axis with the light beam as a center. Item 2. The optical measurement method for a remote object according to Item 1. 4. The optical measuring method for a remote object according to claim 1, wherein the light source uses a front-back and left-right symmetrical laser beam centering on one point. 5. The frequency measurement is calculated from a measured value of the periodicity of the position variation of the center of gravity of the imaged light point of the image pickup surface based on the height variation (at a fixed position) of the fluctuating object surface. Item 2. The optical measurement method for a remote object according to Item 1. 6. An object to be measured is provided with a light-emitting body, which is photographed by a camera to obtain the position of the center of gravity of the light spot on the image pickup surface, and the object to be measured is calculated from the distance between the reference position and the center of gravity set in advance on the image pickup surface. An optical measuring method for a remote object, which is characterized by measuring a position variation such as vibration, rotational extension and the like and a velocity. 7. The camera has means for converting a change in light quantity on the imaging surface into a change in electric quantity, and the position showing the maximum value of the converted electric quantity on the X-axis and the Y-axis is measured to obtain a center of gravity. The optical measuring method for a remote object according to claim 1 or 6, characterized in that: 8. The position variation of the center of gravity of the imaging light points on both sides is simultaneously measured with respect to the variation of the distance from the both sides of the measurement object to the subject (calculated) (sandwiched).
An optical measuring method for a remote object, which comprises measuring the thickness of an object. 9. An optical system for a remote object, characterized in that the axial "twist" or transmitted power (load) is measured from the displacement of the center of gravity of the imaged light points of two constant emission points on the axis of the object to be measured. Measuring method.