JPH0743115A - Distance measurement method and distance measurement device - Google Patents

Abstract

PURPOSE:To provide a density value or color information regarding an object, together with a distance up to the object. CONSTITUTION:Reflected light from a measurement object 4 is separated into infrared and light not including the infrared via a mirror 8. Also, the infrared forms the image of the object 4 on a distance image pick-up element 62, and a distance up to the object 4 can be obtained from information processed with a distance image processing section 5 and the position of a scanning mirror 3. In addition, the light other than the infrared forms an image on a density image pick-up element 61, and a density value is thereby obtained. Also, the mirror 8 is slightly dislocated and images before and after the dislocation are superposed, thereby providing an image having improved resolution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring method and a distance measuring device suitable for measuring the shape of a three-dimensional object.

[0002]

2. Description of the Related Art For measuring the three-dimensional coordinate position of the surface of an object to be measured, that is, in order to measure a three-dimensional shape, a method for obtaining a distance to the object to be measured in real time while scanning slit light is disclosed in, for example, Japanese Patent Laid-Open No. No. 62-228106. This is to detect the slit light reflected from the object to be measured by scanning the slit light in real time using a distance image pickup device such as a non-scanning image pickup device.
The coordinates are uniquely set in the space.

FIG. 3 shows an example of the configuration of such a device.
The light emitted by the light source 1 such as a laser source is slit by the optical system 2, and the slit light is scanned on the measurement target object 4 by rotating the scanning mirror 3.

The light reflected from the object 4 to be measured is imaged on the range image pickup device 6 by the optical system 7. The timing at which the reflected slit light from the object to be measured 4 crosses each cell 6C arranged two-dimensionally within the distance image pickup device 6 is obtained by using a differentiating circuit of the distance image processing unit 5 and the scan at that time is obtained. The rotational position of the mirror 3 is obtained. Based on the rotational positional relationship of the scanning mirror 3, each cell 6 of the range image pickup device 6 is operated on the principle of triangulation.
The distance to the measurement target object 4 is measured for each C. That is, the resolution of the distance image obtained in this case is determined only by the number of cells 6C arranged in the distance image pickup device 6.

[0005]

However, in the handling work by the robot, various inspection works and the like, in addition to the three-dimensional position coordinates of the object to be measured, there are cases where the gray value corresponding thereto is required. That is, although the three-dimensional coordinate position of the measurement target object 4 corresponding to each cell 6C of the distance image pickup device 6 is obtained in the distance image, the grayscale value at this three-dimensional position is often required.

However, in the conventional distance measuring device,
Only the three-dimensional coordinate position data corresponding to each cell of the range image pickup device was obtained, and the brightness of the surface of the object to be measured corresponding to the three-dimensional position, that is, the grayscale image was not obtained.

As a solution to this problem, it is conceivable to measure the brightness of the surface of a conventional general measuring object in the form of an image signal by using a scanning type image input device such as a CCD camera. .

FIG. 4 shows a three-dimensional coordinate position of an object 4 to be measured and its brightness or brightness using a range image input device 6D including a range image pickup device and a grayscale image input device 6T such as a CCD camera from different positions. The mode which measures each and color is shown. However, each brightness or color measured by the grayscale image input device 6T is determined by the distance image pickup device 6
It was very difficult to accurately determine where the three-dimensional coordinate position obtained by D corresponds.

Further, when the slit light scans the object to be measured at the time of capturing an image by a grayscale image pickup device such as a CCD, noise due to the scanning is mixed into the image. In order to avoid this, when the slit light is not irradiated on the measurement target object, the image is captured by the grayscale image pickup device, but with that configuration, the three-dimensional coordinate position of the measurement target object is taken. And its brightness or color cannot be measured at the same time, which requires a long time for measurement.

Further, the number of cells 6C arranged in the range image pickup device 6 cannot be set to a certain number or more due to problems in the manufacturing process of the range image pickup device 6 or the like. Therefore, a range image having a necessary and sufficient resolution may not be obtained.

The present invention has been made in view of the above circumstances, and is intended to obtain information about the grayscale value or color of an object to be measured without being affected by noise and to obtain a necessary and sufficient resolution. is there.

[0012]

In order to solve such a problem, the invention of claim 1 projects slit light on the surface of the object to be measured, and the reflected light from the object to be measured constitutes an imaging surface. In the distance measurement method that detects the timing of passing through the cell and measures the distance to the object to be measured, the reflected light is dispersed, one of the lights measures the distance to the object to be measured, and the other light measures the object. It is characterized by measuring the gray value or color of an object.

The invention according to claim 2 is characterized in that it is divided into one in which either infrared light or ultraviolet light is extracted and one in which the extracted light is not included.

The invention according to claim 3 is characterized in that the physical position for the spectral separation is made movable.

The invention of claim 4 is characterized in that the images obtained as a result of moving the spectral positions are superimposed.

According to a fifth aspect of the present invention, slit light is projected onto the surface of the object to be measured, the timing at which the reflected light from the object to be measured passes through the cells constituting the image pickup surface, and the object up to the object to be measured is detected. In a distance measuring device that measures a distance, a spectroscopic unit (for example, a mirror 8) that disperses reflected light,
Distance image measuring means (for example, the distance image pickup device 6) that measures the distance to the object to be measured by one of the split lights.
2 and a distance image processing unit 5) and a grayscale image processing unit (for example, a grayscale image pickup device 6) that measures the grayscale value or color of the distance measurement portion of the measurement target object by the other spectrally separated light.
1 and a grayscale image processing unit 11).

According to a sixth aspect of the present invention, moving means (for example, the linear motor 9 and control unit 10) for moving the spectroscopic means in the optical axis direction and addition means (for example, a buffer) for superposing the images before and after the movement. A memory 19) is further provided.

[0018]

According to the present invention, the slit light reflected from the object to be measured is split into light containing visible light and light not containing visible light, and the distance is measured by one light. , The gray value or color is measured by the other light.

According to the third, fourth and sixth aspects of the present invention, the images having a slightly different position are superposed, so that the number of pixels is substantially increased, and an image having a high resolution can be obtained.

[0020]

1 is an optical path diagram showing an embodiment of a distance measuring device according to the present invention. In this embodiment, the three-dimensional coordinate position and the brightness of the surface of the measurement target object are simultaneously measured in real time. Light (infrared) emitted by a light source 1 including an infrared laser source that is invisible light
Are slitted by the optical system 2, and the slit light is scanned by the scanning mirror 3 including a galvanometer mirror or the like.
Is reflected using. The slit light is scanned on the measurement target object 4 by rotating the scanning mirror 3 by the motor 15 driven by the control unit 14.

In the range image pickup device 62 sensitive to infrared rays and the grayscale image pickup device 61 made of CCD or the like sensitive to visible light, the image of the object 4 to be measured is recorded by the optical system 7.
And the mirror (dichroic mirror) 8 are arranged at a position where an image is formed. The mirror 8 reflects only infrared light and transmits other visible light, and freely moves on the optical axis as described later. It can be configured.

That is, when the light from the object 4 to be measured via the optical system 7 reaches the mirror 8, the infrared light is reflected by the mirror 8.
However, visible light having a shorter wavelength than infrared light is transmitted through the coating on the surface.

Therefore, the infrared light is reflected by the mirror 8,
The other light (the object to be measured 4 is also irradiated with normal visible light and its reflected light) forms an image on the distance image pickup device 62, passes through the mirror 8, and the grayscale image pickup device 61.
Image on top. The individual cells 62C and 61C forming the range image pickup device 62 and the grayscale image pickup device 61 are associated with each other by appropriate calibration or the like.

With this configuration, infrared light slit light is imaged on the distance image pickup element 62, and the distance image processing section 5 measures the distance in real time as in the conventional case. That is, the visible light is converted into the grayscale image pickup device 61.
At the same time, the infrared image of the same portion as the image formed on the grayscale image pickup device 61 is formed on the distance image pickup device 62 as the image of the object 4 to be measured. Here, the positional relationship between each cell 61C of the grayscale image pickup device 61 and each cell 62C of the distance image pickup device 62 is uniquely determined, and the grayscale image processing unit 1 is determined from the output of the cell 16C.
In 1, the obtained brightness at each three-dimensional coordinate position of the measurement object 4 can be identified by the distance image processing unit 5 from the output of the corresponding cell 62C.

According to the example of FIG. 1, the incident light is split by using the mirror 8 so that the three-dimensional coordinate position of the object to be measured 4 measured by the distance image pickup device 62 and the CCD.
Accurate correspondence with the brightness measured by the grayscale image pickup device 61 is possible.

Further, by using the mirror 8 having the characteristic of reflecting only infrared light, most of the reflected light of infrared slit light can be imaged on the distance image pickup element 62. It is possible to prevent the light intensity from being attenuated. Light having a shorter wavelength than infrared light including visible light is transmitted through the mirror 8 and the grayscale image pickup device 6 such as CCD.
The influence of the slit light (infrared ray) which is imaged at 1 and is used for measuring the three-dimensional coordinate position of the measurement object 4 is removed. As a result, the brightness at the three-dimensional coordinate position of the measurement target object can be accurately measured.

The controller 10 in FIG. 1 drives the linear motor 9 to quantitatively move the position of the mirror 8 in the optical axis direction. As a result, the position of the image formed on the distance image pickup element 62 can be moved in parallel by an arbitrary amount with high accuracy.

FIG. 2 shows an example of the configuration of a range image generating method for obtaining a high resolution image by moving the position of the mirror 8 of FIG. 1 by a linear motor 9. That is, in the example of FIG. 2, the position of the mirror 8 is translated in the incident light direction by a predetermined distance by the linear motor 9 having the control unit 10 that translates the mirror 8 in the incident light axis direction in FIG. By adding the image captured by moving the image in the lateral direction by half the cell 62C interval (that is, the pitch P) of the range image pickup device 62 and the image captured before the movement by the adder 18, This is an example in which the directional resolution is doubled.

First, FIG. 2A shows a state in which the image 12A is formed on the range image pickup device 62 before the mirror 8 moves. That is, it shows that a distance image is obtained on the distance image pickup device 62 by scanning the slit light on the object 4 to be measured by the scanning mirror 3 of FIG.

In FIG. 2B, the mirror 8 is moved by a predetermined distance so that the image 12B on the distance image pickup element 62 is laterally displaced by half the distance between the cells 62C in the lateral direction, that is, P / 2. The imaged state is shown. That is, here also, it is shown that the scanning mirror 3 in FIG. 1 scans the measurement target object 4 with slit light, and a range image is obtained on the range image pickup device 62. The movement of the mirror 8 is
This is performed at a timing immediately before the scanning of the slit light on the measurement target object 4 by the scanning mirror 3 is started.

FIG. 2C shows an image 1 formed on the range image pickup device 62 in the state shown in FIG.
2A is shown as being sensed by each cell 62C arranged in the range image pickup device 62. That is, FIG. 2C shows that a triangular image is formed on the cell 62C filled in black, and the resolution of this image is the cell 62C in the range image pickup device 62.
Is determined by the number of.

FIG. 2D shows the image 1 formed on the range image pickup device 62 in the state shown in FIG. 2B.
2B is shown as being sensed by each cell 62C arranged in the range image pickup device 62. That is, FIG. 2D shows that a cell 62C that is filled with black is
It shows that a triangular image is being captured.

FIG. 2E shows that the image picked up as shown in FIG. 4B and the image picked up as shown in FIG. 2D are combined by the adder 18, that is, superposed. Shows the image obtained by. By superimposing the images obtained by shifting the positions in this way, a range image 13 having double the horizontal resolution is obtained.

That is, the range image taken as shown in FIG. 2 (c) is stored in the buffer memory 19 in the range image processing unit 5 in FIG. 1 and taken as shown in FIG. 2 (d). The range image is also stored in the buffer memory 19 in the same manner, and the correspondence between the pixels in the lateral direction of the range image obtained by the image pickup of FIG. 2C is within the range image obtained by the image pickup of FIG. 4D. Embed the pixels to be used. As a result, by performing the scanning of the slit light twice, a single distance image with double the horizontal resolution is generated.

In the example of FIG. 1, the mirror 8 reflects only infrared light, and the incident light is dispersed by using a mirror that transmits visible light having a shorter wavelength than that, but instead of the mirror, a prism or the like is used. An optical element may be used.

In the example of FIG. 1, a monochrome gray-scale image pickup device is used, but when picking up a color image, a color image pickup device may be used instead. For example, what is used as a color image pickup device is a color CCD image pickup device in which filters of three colors R (red), G (green) and B (blue) are evenly arranged on each pixel of the CCD image pickup device. Can be given. This means that for the pixel below the R filter, only the R (red) component is detected as its brightness in the incident light to the image sensor. G
The same applies to (green) and B (blue).
An image for each of G and B is generated, and a color image is read.

In the example of FIG. 1, slit light is generated using infrared light, but ultraviolet light can also be used. At this time,
A spectral mirror that reflects only ultraviolet light and a range image pickup device that has a photosensitive characteristic for ultraviolet light will be used.

In the example of FIG. 2, the resolution is doubled. However, the amount of movement of the image formed on the range image pickup device is reduced, so many images are picked up, and a large number of images are obtained. By combining the images, it is possible to further increase the resolution.

In the examples of FIGS. 1 and 2, the resolution of the range image is improved in the lateral direction, but the mirror 8 of FIG. 1 is rotated 90 degrees about the incident optical axis, and the range image is captured accordingly. By disposing the element 62 and the linear motor 9 at predetermined positions and performing similar processing, it is possible to improve the resolution of the range image in the vertical direction.

In the example of FIG. 1, a linear motor is used as the method of moving the spectral mirror, but an actuator that performs linear movement, such as a piezo element that can perform accurate positioning, may be used.

[0041]

As described above, according to the inventions of claims 1, 2 and 5, the slit light reflected from the object to be measured is split into light containing visible light and light not containing visible light. The light is used to measure the distance, and the other light is used to measure the grayscale value or the color. Therefore, the distance to the measurement object and the grayscale value or the color of the portion where the distance is measured can be simultaneously measured.

According to the third, fourth and sixth aspects of the present invention, the number of pixels is substantially increased by superimposing the position images whose positions are slightly shifted from each other, and an image with good resolution can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a state in which an image of an object to be measured is formed by shifting the position on a range image pickup device, and the images are combined.

FIG. 3 is a block diagram showing an example of a conventional measuring method.

FIG. 4 is a diagram showing an example of means for simultaneously obtaining distance information and grayscale value information in a conventional method.

[Explanation of symbols]

 1 Light Source 2 Optical System 3 Scanning Mirror 4 Object to be Measured 5 Distance Image Processing Unit 6 Distance Image Imaging Device 7, 7A Optical System 8 Mirror 9 Linear Motor 10 Control Unit 13 Image 18 Adder 19 Buffer Memory 61 Gray Image Imaging Device 62 Range image sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G06T 7/00 1/00 7/60 8837-5L G06F 15/70 350 J

Claims (6)

[Claims] 1. A distance to the object to be measured is measured by projecting slit light on the surface of the object to be measured and detecting the timing at which reflected light from the object to be measured passes through a cell forming an imaging surface. In the distance measuring method, the reflected light is dispersed to measure the distance to the object to be measured by one of the lights, and the gray value or color of the object to be measured is measured by the other light. Distance measurement method. 2. The distance measurement according to claim 1, wherein the spectrum is divided into one in which either infrared light or ultraviolet light is extracted and one in which the extracted light is not included. Method. 3. The distance measuring method according to claim 1, wherein a physical position for the spectral separation is made movable. 4. The distance measuring method according to claim 3, wherein the images obtained as a result of moving the spectral position are superimposed. 5. The distance to the measurement target object is measured by projecting slit light on the surface of the measurement target object and detecting the timing at which the reflected light from the measurement target object passes through a cell forming an imaging surface. In the distance measuring device, a spectroscopic unit that disperses the reflected light, a distance image measuring unit that measures the distance to the object to be measured by the one spectrally separated light, and the measurement by the other spectrally separated light. A distance measuring device, comprising: a grayscale image processing means for measuring a grayscale value or a color of a distance measuring portion of a target object. 6. A moving means for moving the spectroscopic means in the optical axis direction, and an adding means for superimposing a distance image obtained before the movement by the moving means and a distance image obtained after the movement. The distance measuring device according to claim 5.