JP4767403B2 - Three-dimensional measuring apparatus and three-dimensional measuring method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a three-dimensional measuring apparatus and a three-dimensional measuring method for measuring a three-dimensional shape using a light cutting method. In particular, the present invention relates to a three-dimensional measuring apparatus and a three-dimensional measuring method used by being attached to a movable device such as a robot.
[0002]
[Prior art]
A light cutting method is used as a method for measuring the distance to a three-dimensional object at a distant place and the shape of the three-dimensional object. In this light cutting method, slit light is projected onto an object to be measured, and the cut surface by the light is observed from another direction as if the object is cut by a band of light.
[0003]
FIG. 6 is a cross-sectional view showing the principle of measurement by the light cutting method. In FIG. 6, reference numeral 901 denotes a slit light source provided in the three-dimensional measuring apparatus, 902 denotes an imaging lens provided in the three-dimensional measuring apparatus, 903 denotes an image forming surface of the lens 902, and 905 denotes a connection. This is the center point of the image plane 903, and this center point 905 is the intersection of the image plane 903 and the imaging direction axis. Reference numeral 901a denotes a slit light surface irradiated from the slit light source 901, reference numeral 910 denotes a measurement target object, and reference numeral 911 denotes one of irradiation points where the slit light surface 901a irradiates the measurement target object.
[0004]
Here, the distance between the slit light source 901 and the center of the lens 902 is L (base line length). A reference line on the drawing indicates a direction perpendicular to a measurement surface (a surface perpendicular to the cross section of FIG. 6) including a line connecting the slit light source 901 and the lens 902. The angle of the slit light with respect to the measurement surface is θ, and the angle of the line connecting the center of the lens 902 and the irradiation point 911 with respect to the measurement surface is φ. Here, in order to obtain the distance Z from the measurement surface to the measurement target object 910, the following equation may be calculated.
[0005]
Z = L · tan (θ) · tan (φ) / (tan (θ) + tan (φ))
However, “tan ()” represents a tangent function.
[0006]
The above φ is expressed by the following equation using an angle φ0 with respect to the imaging surface in the imaging direction (a direction connecting the center point 905 and the center of the lens 902) and a displacement angle φ1 of the irradiation point 911 with respect to the imaging direction.
[0007]
φ = φ0 + φ1
[0008]
Further, the displacement angle φ1 is expressed by the following equation using the distance l between the lens 902 and the imaging plane 903 and the displacement Δx from the center point 905 of the image of the irradiation point 911 on the imaging plane 903.
[0009]
φ1 = arctan (Δx / l)
However, “arctan ()” represents a tangent inverse function.
[0010]
As described above, the slit light is irradiated not only on the cross section but also on the surface of the measurement target object 910 so as to form a linear cutting line. The distance to the location can be measured.
[0011]
Using the above principle, it is possible to measure the three-dimensional shape of the measurement target object 910 using the slit light surface 901a at various angles (θ). In the prior art, slit light is mechanically scanned so as to continuously change the irradiation angle of the slit light source 901 in order to increase the measurement density.
[0012]
[Problems to be solved by the invention]
However, in order to mount the above three-dimensional measuring device on a device that moves itself and receives an impact intermittently when moving, such as a biped robot, for example, a mechanical scan as described in the related art There is a problem with the method. This is because taking anti-vibration measures so that the scanning function is not hindered by an impact at the time of movement leads to higher costs in terms of size and durability. In particular, the legged mobile robot has a lot of vibration, and the mechanical scanning method tends to damage the driving unit such as a motor.
[0013]
Further, simply increasing the number of slit beams instead of using the scanning method has a problem that a detection limit is reduced due to a reduction in beam power and a detection distance range is reduced due to a reduction in slit interval.
[0014]
Japanese Patent Laid-Open No. 10-68607 discloses that a plurality of light cutting lines are formed on a reference plane so as to be parallel to each other at a constant interval, and each light cutting line has a plurality of light colors different from each other. There has been disclosed a technique in which an optical cutting line captured by an image input device including a camera is extracted for each color signal to obtain a distance. However, in such a method, it is indispensable to use a color TV camera, and there has been a problem that it leads to high cost or restrictions on device design. In addition, depending on the relationship between the color of the measurement object and the color of the light cutting line, there is a problem that it cannot be determined as a correct color and the light cutting line cannot be recognized correctly.
[0015]
The present invention has been made in consideration of the above-mentioned circumstances, and in the three-dimensional measurement using the light cutting method with multi-slit light, there is a disadvantage caused by mechanically scanning the slit light or reducing the slit interval. It is an object of the present invention to provide a three-dimensional measuring apparatus and a three-dimensional measuring method capable of improving the measurement density without inviting.
[0016]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is to form a linear cut line on the surface of the measured object by irradiating the measured object a plurality of slit light from each light emitting unit,該切disconnection In a three-dimensional measurement apparatus that measures the shape of the measurement target object by photographing the image of the measurement target object, at least two light emission means having different radiation patterns of slit light from each other, and the light emission means sequentially time-divisionally the measurement target object The light emission control means for controlling the light emission and the slit light emitted from each of the light emission means are formed substantially in parallel, and the cutting line formation position by the slit light is shifted in the alignment direction of the slit light and is different from each other. a cutting line forming position adjusting means for adjusting the provided as the cutting line forming position adjusting means, the emission position interval control hand controlling the distance between a plurality of said light emitting means And gist three-dimensional measuring apparatus, characterized in that it.
Here, as the light emitting means, for example, a combination of a laser light source and a slit plate having a plurality of slit holes is used. For example, a laser diode is used as the laser light source. Further, as the imaging means, for example, a digital still image camera or a digital moving image camera is used. Further, as the light emission control means, for example, a device that outputs a pulse signal for independently controlling the light emission intensity of each light emission means is used.
[0017]
With the configuration as this, made different cutting line forming position by the slit light emitted from the light emitting means, it becomes possible to measure the different positions on the surface of the measured object, and thus to improve the measurement density as a result .
[0019]
In the three-dimensional measurement apparatus of the present invention, at least two imaging units are provided, and the distance between the first imaging unit and the light emitting unit is different from the distance between the second imaging unit and the light emitting unit. As described above, the imaging means and the light emitting means are arranged.
As a result, the object to be measured having a wide distance range is captured using the imaging unit having a relatively small distance from the light emitting unit, and the imaging unit having a relatively large distance from the light emitting unit is used. It is possible to perform highly accurate three-dimensional measurement.
[0020]
Further, the present invention forms a linear cutting line with a first pattern on the surface of the measurement target object by irradiating the measurement target object with a plurality of slit lights from the first light emitting means. A first process of measuring a shape of the measurement target object by photographing a cutting line by a pattern with an imaging unit, and irradiating a plurality of slit lights from a second light emitting unit to the surface of the measurement target object. A linear cutting line is formed by a second pattern that is substantially parallel to the first pattern and shifted in the direction in which the slit light is arranged, and the cutting line by the second pattern is photographed by an imaging means, and the measurement object a second step of measuring a shape, in accordance with the measurement result in the first step, made different by shifting the position of the cutting line of the second pattern in the second step in the alignment direction of the slit light And process, the three-dimensional measurement method characterized by having a subject matter.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the three-dimensional measuring apparatus according to the embodiment. This three-dimensional measuring device is mounted on a biped walking robot, measures the distance using the floor on the robot's moving path as the object to be measured, and adjusts the landing position of the foot when biped walking. The purpose is to control the legs.
[0023]
In FIG. 1, reference numerals 1 a and 1 b denote laser light sources (light emitting means) that are provided at predetermined intervals and each irradiate multi-slit light onto a measurement target object. Reference numeral 2 denotes a camera (imaging means) that captures an object to be measured irradiated with slit light from the laser light sources 1a and 1b. Reference numeral 3 denotes a light emission control unit (light emission control means) for controlling the timing of light emission of the laser light sources 1a and 1b and the timing of imaging by the camera 2 by outputting timing signals for the laser light sources 1a and 1b and the camera 2. ).
[0024]
An image capturing unit 4 captures an image captured by the camera 2 and stores it in an image memory after A / D conversion (analog / digital conversion). 5 is based on the image captured by the image capturing unit 4. It is a distance estimation part which calculates the distance to a measurement object. Reference numeral 8 denotes a movement route determination unit that determines the movement route of the robot. Reference numeral 6 denotes a landing position of the robot foot based on the route information determined by the movement route determination unit 8 and the distance calculation result by the distance estimation unit 5. The landing position determination unit 7 is a leg control unit that controls a motor that drives the robot leg while balancing the robot so that the foot is brought to the landing position determined by the landing position determination unit 6.
[0025]
FIG. 2 is a timing chart showing a waveform of a timing signal output from the light emission control unit 3. (A) of FIG. 2 is a signal for controlling the beam intensity of the laser A by the laser light source 1a. FIG. 2B shows a signal for controlling the beam intensity of the laser B by the laser light source 1b. Further, (c) in FIG. 2 is a vertical synchronization signal for controlling the timing of imaging by the camera 2. With the control signal as shown in FIG. 2, the laser light sources 1a and 1b alternately irradiate each multi-slit light, and the camera 1 images the measurement target object irradiated by each laser light source.
[0026]
FIG. 3 is a sectional view showing an irradiation pattern of slit light by the laser light sources 1a and 1b. In FIG. 3, the irradiation pattern of the slit light from the laser light source 1a is indicated by a solid line, and the irradiation pattern of the slit light from the laser light source 1b is indicated by a broken line. As shown in the timing chart of FIG. 2, since the laser light sources 1a and 1b irradiate alternately, the distance measurement using the slit light according to the solid line or broken line pattern of FIG. 3 is performed at each irradiation timing. . For example, in the area of reference numeral 21 shown in FIG. 3 (area where the distance is about 1.1 to 1.2), the irradiated portions of the slit light of the laser light sources 1a and 1b are close to each other, so the total measurement density is The measurement density in the case of using any one of the laser light sources 1a and 1b is not much different. However, for example, in the region indicated by reference numeral 22 shown in FIG. 3 (region where the distance is about 1.4 to 1.6), the laser light sources 1a and 1b complement each other, thereby using a single laser light source. In comparison, the total measurement density is doubled at maximum.
[0027]
Next, a second embodiment of the present invention will be described. FIG. 4 is a block diagram showing the configuration of the three-dimensional measuring apparatus according to the embodiment. The feature of the configuration shown in FIG. 4 is that a light source interval control unit 11 (cutting line formation position adjusting unit, light emission position interval control unit) is provided, and the laser light sources 1a and 1b are controlled according to the control of the light source interval control unit 11. The interval is variable. The other configuration is the same as that shown in FIG.
[0028]
Thus, by making the interval between the laser light sources 1a and 1b variable, it is possible to change the pattern relationship of multi-slit light by both light sources. For example, in the cross-sectional view shown in FIG. 3, the measurement density in the region 22 is higher than that in the case of using a single laser light source, but the measurement density is not improved so effectively in the region 21. However, by making the distance between the laser light sources 1a and 1b variable as in the second embodiment, it is possible to move a region where the measurement density can be increased.
[0029]
That is, it is possible to adjust the cutting line formation positions by the slit light emitted from the respective laser light sources to be different from each other. Therefore, for example, first, the distance to the measurement target object is measured at a low density, and the light source interval control unit 11 controls the distance between the laser light sources 1a and 1b so that high density measurement is possible according to the measurement result. To do. This makes it possible to perform high-density measurement in any distance zone.
[0030]
That is, by irradiating the measurement target object with a plurality of slit lights from the first light emitting means, a linear cutting line with the first pattern is formed on the surface of the measurement target object, and the cutting line with the first pattern is formed. A first process of measuring the shape of the measurement target object by imaging the image, and the first pattern on the surface of the measurement target object by irradiating a plurality of slit lights from the second light emitting means Includes a second process of forming a linear cutting line with a different second pattern and photographing the cutting line with the second pattern with an imaging means to measure the shape of the object to be measured. In the method, the second pattern in the second process is made different according to the measurement result in the first process.
[0031]
Next, a third embodiment of the present invention will be described. FIG. 5 is a block diagram showing the configuration of the three-dimensional measuring apparatus according to the embodiment. The feature of the configuration shown in FIG. 5 is that two cameras, a narrow base length camera 2a and a wide base length camera 2b, are provided. The narrow base length camera 2a is provided relatively close to the laser light sources 1a and 1b and is wide. The base line length camera 2b is provided at a position relatively distant from the laser light sources 1a and 1b. That is, in this embodiment, at least two cameras are provided, and the camera and the laser light source are arranged so that the distance between the first camera and the laser light source is different from the distance between the second camera and the laser light source. Yes. The other configuration is the same as that shown in FIG.
[0032]
When the angle of view of the narrow baseline length camera 2a and the wide baseline length camera 2b are equal to each other, the image taken by the narrow baseline length camera 2a exists in a wider distance range than the image taken by the wide baseline length camera 2b. The object to be measured can be captured. On the other hand, as is apparent from the principle of the light cutting method, by using an image taken with the wide baseline length camera 2b, distance measurement can be performed with higher accuracy than when using an image taken with the narrow baseline length camera 2a. it can. That is, by appropriately using the narrow base length camera 2a and the wide base length camera 2b as appropriate, it is possible to measure the distance to the measurement target object in a wider range with higher accuracy. That is, for example, first, the distance to the object to be measured is measured with rough accuracy using the narrow baseline length camera 2a, and if necessary, the imaging direction of the wide baseline length camera 2b is adjusted according to the distance measurement result. Next, the distance to the object to be measured is measured with high accuracy using the wide baseline length camera 2b. Thereby, it becomes possible to measure a measurement target object in a wide distance range with high accuracy.
[0033]
In the first to third embodiments, the two light sources 1a and 1b are used. However, the number of light sources is not limited to two, and more light sources are used. The irradiation with the multi-slit light used may be sequentially performed to measure the distance to the measurement target object. Thereby, it is possible to perform a higher density measurement or to perform a high density measurement in various distance ranges while fixing the distance between the light sources.
[0034]
【The invention's effect】
As described above, according to the present invention, at least two light emitting means having different radiation patterns of slit light and light emission control means for controlling the light emitting means to sequentially irradiate the measurement target object in a time division manner. In order to measure the shape of the object to be measured by photographing the cutting line with an imaging means, for example, when attached to a biped robot, even in an environment where an impact is applied during operation, it is low cost and high density Measurement can be performed. In addition, since it is not necessary to use a plurality of emission colors, the apparatus configuration is simplified and the cost can be reduced. In addition, since the plurality of light emitting units are driven in a time-sharing manner, power consumption can be reduced.
[0035]
In addition, according to the present invention, since the cutting line formation position by the slit light irradiated from each light emitting means is adjusted to be different from each other, it becomes possible to measure different positions on the surface of the measurement target object, and wide The measurement area can be measured at high density.
[0036]
In addition, according to the present invention, at least two imaging units are provided, and the imaging unit and the light emitting unit are configured such that the distance between the first imaging unit and the light emitting unit is different from the distance between the second imaging unit and the light emitting unit. In order to arrange the means, the imaging means having a relatively large distance from the light emitting means is used to capture the measurement target object having a wide distance range and the imaging means having a relatively large distance from the light emitting means. By using this, it becomes possible to perform highly accurate three-dimensional measurement. Therefore, it is possible to measure a wider measurement area with high accuracy.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a three-dimensional measuring apparatus according to a first embodiment of the present invention.
FIG. 2 is a timing chart showing timing signals for controlling the timing of light emission and imaging in the three-dimensional measuring apparatus according to the same embodiment.
FIG. 3 is a cross-sectional view showing a pattern of slit light emitted from two laser light sources in the three-dimensional measuring apparatus according to the same embodiment.
FIG. 4 is a block diagram showing a configuration of a three-dimensional measuring apparatus according to a second embodiment of the present invention.
FIG. 5 is a block diagram showing a configuration of a three-dimensional measuring apparatus according to a third embodiment of the present invention.
FIG. 6 is a cross-sectional view showing the principle of distance measurement using an optical cutting method as the basis of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1a, 1b Laser light source 2 Camera 2a Narrow base length camera 2b Wide base length camera 3 Light emission control part 4 Image capture part 5 Distance estimation part 6 Landing position determination part 7 Leg control part 8 Movement path determination part 11 Light source space control part

Claims (3)

Each multiple slit light from the light emitting means to form a linear cutting line on the surface of the measured object by irradiating the measured object, the shape of the measured object The sections disconnected by photographing by the image pickup means In the three-dimensional measuring device that measures
At least two light emitting means having different radiation patterns of slit light,
Light emission control means for controlling the light emission means to sequentially irradiate the measurement object in a time-division manner;
Cutting line forming position adjusting means for adjusting the slit light irradiated from each of the light emitting means to be substantially parallel to each other and adjusting the cutting line forming position by the slit light to be different from each other in the alignment direction of the slit light ;
Comprising
The three-dimensional measuring apparatus according to claim 1, wherein the cutting line forming position adjusting means is a light emission position interval control means for controlling a distance between the plurality of light emitting means. Comprising at least two imaging means;
The imaging means and the light emitting means are arranged so that a distance between the first imaging means and the light emitting means is different from a distance between the second imaging means and the light emitting means. The three-dimensional measuring apparatus according to 1. By irradiating the object to be measured with a plurality of slit lights from the first light emitting means, a linear cutting line by the first pattern is formed on the surface of the object to be measured, and the cutting line by the first pattern is imaged. A first step of photographing by means and measuring the shape of the object to be measured;
By irradiating a plurality of slit lights from the second light emitting means, a linear cutting line by a second pattern which is substantially parallel to the first pattern and shifted in the direction in which the slit lights are arranged on the surface of the measurement object. A second step of measuring the shape of the object to be measured by photographing the cutting line of the second pattern with an imaging means,
In accordance with the measurement result in the first step, the step of shifting the position of the cutting line of the second pattern in the second step in the direction of the slit light to make it different,
A three-dimensional measurement method characterized by comprising:

Images