JP2733170B2 - 3D shape measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CAD data input device for inputting an external shape from a molding die or a model of various designed products to finish a final design drawing, and for education and sales. 3D video material input device used,
The present invention relates to a medical diagnostic device or a three-dimensional shape measuring device used as a visual sensor of a robot.

[0002]

2. Description of the Related Art A three-dimensional shape measuring apparatus measures a three-dimensional shape of an object to be measured. Here, in order to measure the three-dimensional shape, a measurement optical mechanism for irradiating the measurement light beam from the light source toward the measurement object arranged on the reference plane, and a scattered light beam reflected from the measurement object surface Is generally received by the light receiving unit, and the three-dimensional shape of the measurement object is determined by obtaining three-dimensional shape information on the measurement object from the detection result of the scattered light beam by the light receiving unit. For example, as shown in FIG. 2 and the like, there is one that measures based on triangulation. on the other hand,
Some attempt to detect color information along with such shape information. For the color of the surface of the measurement object, a color image of the measurement object is captured using a two-dimensional color camera, and A method of obtaining the color of each point is generally adopted.

[0003]

However, when measuring color information such as the chromaticity of a certain point on the surface of an object having a three-dimensional shape or the lightness of that part, if a two-dimensional camera is used as in the prior art, , The normal to the surface of the object to be measured,
Since the optical axis of the light source and the optical axis of the camera generally do not coincide, the measured lightness or the like changes depending on the direction of the surface (the lightness is detected as changing). As a result, for example, in the chromaticity detection, if the chromaticity of the surface of the measurement object is determined based on the absolute light amounts of the reflected lights of the RGB color components, it is difficult to obtain the correct chromaticity due to the inclination of the surface and the brightness of the light source. It may be. The same can be said for the brightness of the surface.

Accordingly, it is an object of the present invention to provide a three-dimensional shape measuring apparatus capable of correctly obtaining color information such as chromaticity and lightness of the surface of an object to be measured.

[0005]

In order to achieve this object, a three-dimensional shape measuring apparatus according to the present invention is characterized in that the three-dimensional shape measuring apparatus includes a normal direction of the surface of the object to be measured and a scattering direction of a scattered light beam incident on the light receiving portion. The scattered light vs. normal angle, the observation direction detection means for guiding from the three-dimensional shape information, and the scattered light vs. normal angle obtained by the observation direction detection means, the irradiation light amount of the measurement light beam illuminating the surface of the measurement object and The amount of light received by the light receiving unit is adapted to Lambert's cosine law, and a diffuse reflection coefficient deriving unit for obtaining a diffuse reflection coefficient of the surface of the measurement object is provided to determine color information of the surface of the measurement object. The color information determining means is provided.

[0006]

That is, in the three-dimensional shape measuring apparatus of the present invention, the normal direction of the surface of each measurement object is calculated and derived based on the shape information obtained in the signal processing unit by the observation direction detecting means. The scattered light versus normal angle, which is the angle between the direction of the line and the scattering direction of the scattered light beam incident on the light receiving unit, is determined. On the other hand, since the amount of light applied to the surface of the object to be measured and the amount of light scattered / reflected from this portion and received by the light receiving unit are measured and known, the diffuse reflection coefficient of the surface to be measured is determined from these relationships. , And Lambert's cosine law. When the light beam is monochromatic light, the diffuse reflection coefficient determines the brightness of the surface of the object to be measured. When the light beam includes three primary colors, the color of the surface of the object to be measured is determined from the relationship between the diffuse reflection coefficients of the respective colors. The degree is determined. That is, the color information of the measuring object is determined by the color information determining means.

[0007]

According to the above method, when detecting the color information on the surface of the object to be measured, the inclination of the surface of the object to be measured is not the absolute light amount received by the light receiving portion but the diffuse reflection coefficient. And correct color information regardless of the brightness of the light source.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a three-dimensional image input device as an example of a three-dimensional shape measuring device will be described. As shown in FIG. 1, the three-dimensional image input device includes a reference plane 1 on an XY plane.
Irradiates a measurement light beam onto a measurement object 2 placed above the reference plane 1 and placed on the reference plane 1 to irradiate the measurement object 2
A measuring unit 3 for detecting a scattered light beam from the surface, a measurement control unit 4 for controlling the measuring operation of the measuring unit 3, and from the reference plane 1 to the surface of the measuring object 2 based on the data measured by the measuring unit 3. And a model generating unit 6 for reconstructing the measurement object 2 from the three-dimensional data derived by the signal processing unit 5. The measuring unit 3 includes a light source 8 composed of a laser and a one-dimensional image sensor C arranged along the X-axis direction.
A light receiving element 9 made of a CD is disposed to face the scanning mirror 7 with the projection light beam from the light source 8 irradiating the measurement object 2 via the scanning mirror 7 and the fixed mirror 10. An optical head for guiding the scattered light beam from the surface of the measurement object 2 to the light receiving element 9 via the fixed mirror 10 'and the scanning mirror 7, and moving the optical head in the Y axis direction to move the optical head in the Y axis direction. And a scanning mechanism (not shown) for performing the scanning. The measurement control unit 4
Rotates the scanning mirror 7 around an axis parallel to the Y-axis, and causes the measurement light beam from the light source 8 to move in the X-axis direction with respect to the reference plane 1 including the measurement target 2. The scanning mechanism directs the optical head in the Y-axis direction while irradiating the optical head by scanning and guiding the scattered light beam to the light receiving element 9 via the fixed mirror 10 ′, the scanning mirror 7 and the condenser lens 11. Scan. That is, the measurement unit 3 and the measurement control unit 4 constitute a scanning unit that scans the measurement light beam from the light source 8 toward the measurement target 2 on the reference plane 1 at a set scanning density.

The signal processing section 5 comprises the light receiving element 9.
The resulting CCD has a scattered light flux from the reference plane 1
Position to detect for the current scattered light flux
From the deviation from the position and the rotation angle of the scanning mirror 7,
The surface position of the measuring object 2 from the reference plane 1 is calculated and derived.
Put out. That is, as shown in FIG.
Distance X₀X₁Is ΔX₀And the reference plane
Surface position Z of the measuring object 2 from 1₀Is Z₀× θ = ΔX
₀Z₀Ask for. The model student
The component 6 is obtained by scanning in the X direction and scanning in the Y direction.
For each measured point (determined by scan density)
XYZ coordinate data specified by the value in the Z direction
As image data, the shape of the measurement object 2 is
Reproduce on pewter.

Here, the scanning density in the X-axis direction is determined by the sampling interval per scan by the light receiving element 9, and the scanning density in the Y-axis direction is determined by the sampling interval in the Y-axis direction. The scanning density is freely changeable by appropriately setting the sampling interval by the measurement control unit 4. Here, a mechanism for irradiating the measurement light beam from the light source 8 toward the measurement object 2 disposed on the reference plane 1 is defined as an optical mechanism for measurement and scattering of the measurement light beam reflected from the measurement object 2. The light receiving unit 9 for receiving the light beam and a mechanism for guiding the scattered light beam to the light receiving unit 9 are referred to as a light receiving optical mechanism.

The relationship between the measurement light beam emitted from the light source 8 and the R, G, and B wavelength components will be described below. The configuration of the light source 8 is as shown in FIG. That is, there are provided irradiation light control means 12 for selecting and controlling the wavelength of the irradiation light beam, and switches SW1 and SW2 for performing irradiation and stopping irradiation of the laser of each wavelength.
SW3 is provided. And the irradiation light control means 12
, Laser light of each wavelength is emitted in a time-division manner. As the order of irradiation, there is a method of irradiating each wavelength for each detection point, or irradiating with the same Y coordinate by changing the color for each cycle in the X direction. The determination of the color of the surface of the measurement target 2 will be described below. The principle of color discrimination will be described. When the normal angle of the scattered light formed by the scattering direction of the scattered light beam incident on the light receiving unit, which is a camera, with respect to the normal of the surface of the measurement object 2 is φ, the light receiving unit 9 amount I _d to observe the,

[0012]

(Equation 1)

[0013] Here, I _d is the observed light intensity, F _t is the amount of incident light, since φ are each known values in the scattered light anormal angle, diffuse reflection coefficient by the relationship of the above [rho _d
Is required. Therefore, if this is performed for light of each wavelength of RGB, the diffuse reflection coefficients ρ _R , ρ _G , and ρ _B for each light of RGB can be obtained. From this, the color of the object to be measured is determined by taking the ratio of these coefficients. This processing procedure and the configuration of the processing device are shown in FIG.

As shown in FIG. 1, the processing mechanism includes an observation direction detecting means 13, a diffuse reflection coefficient deriving means 14, and a color information determining means 15. In the device, since the three-dimensional shape of the measurement target 2 is obtained by the signal processing unit 5, this information is used. That is, the normal direction of the surface of the measuring object 2 is obtained from the shape information by the observation direction detecting means 13 (Step 1), and the scattered light formed by this direction and the scattering direction of the scattered light beam incident on the light receiving portion 9 is formed. A normal angle φ is derived (step 2). Further, according to Lambert's cosine law, based on the scattered light versus normal angle φ obtained by the observation direction detection means 13, the irradiation light amount of the measurement light beam irradiated on the surface of the measurement object, and the light reception amount received by the light receiving unit 9. Diffuse reflection coefficient ρ of measurement object surface
_d is obtained by the diffuse reflection coefficient deriving means 14 (step 3). Then, by adopting the configuration of the light source described above, for each of the RGB primary colors, the diffuse reflection coefficients ρ _R , ρ _G , and ρ _B for each of the RGB primary colors on the surface of the measurement object are obtained, and the color information determination means is obtained. 15 determines the chromaticity of the surface of the object to be measured based on the ratio of these coefficients (step 4).

Hereinafter, another embodiment of the present invention will be described. a In the above embodiment, an example in which the chromaticity of the surface of the measurement object 2 is measured has been described. However, in order to correctly measure the lightness of the surface, the diffuse reflection coefficient is obtained by irradiating white light. The numerical value may be used as the brightness.

B In the above embodiment, a description was given using a three-dimensional image input device. However, the device is not limited to this, and can be used for other three-dimensional shape measuring devices such as a distance measuring device.

C The configuration of the measuring unit 3 is not limited to the configuration of the embodiment, but may be any configuration as long as it derives three-dimensional coordinates based on the principle described in the previous embodiment. As shown in FIG. 5, the optical head may be composed of a scanning mechanism that scans only the projection light beam and a fixed optical mechanism that guides the scattered light beam to the light receiving element 9.
Instead of a scanning mechanism that scans in the Y-axis direction by moving in the axial direction (which can be easily configured using a motor and a pulley), as shown in FIG. In order to scan the plane formed by the above in the Y-axis direction, a reflecting mirror that is rotatable around the Z-axis may be provided. Select the wavelength of the irradiation light beam for the irradiation light control means.
At the same time as the control, a means for controlling the intensity of the irradiation light according to the sensitivity of the light receiving unit may be provided. The configuration is as shown by the dashed line in FIG.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a three-dimensional image input device.

FIG. 2 is an explanatory diagram showing the principle.

FIG. 3 is a diagram showing a configuration of a laser.

FIG. 4 is an explanatory diagram of a color discrimination processing procedure.

FIG. 5 is a configuration diagram of a main part showing another embodiment.

FIG. 6 is a configuration diagram of a main part showing another embodiment.

[Description of Signs] 1 Reference surface 2 Object to be measured 5 Signal processing unit 8 Light source 9 Light receiving unit 13 Observation direction detection means 14 Diffuse reflection coefficient derivation means 15 Color information determination means φ Scattered light versus normal angle

Claims (1)

(57) [Claims] 1. A measuring optical mechanism for irradiating a measuring light beam from a light source (8) toward a measuring object (2) arranged on a reference plane (1), and A light receiving unit (9) for receiving the scattered light beam reflected from the surface of the measurement object (2); a light receiving optical mechanism for guiding the scattered light beam to the light receiving unit (9); A signal processing unit (5) for calculating and deriving three-dimensional shape information of the measurement object (2) based on a detection result of the scattered light beam; Observation direction detecting means (13) for deriving, from the three-dimensional shape information, a scattered light versus normal angle (φ) formed by a normal direction of the surface and a scattering direction of the scattered light beam incident on the light receiving section (9). And the observation direction detecting means (13).
The scattered light versus normal angle (φ) obtained by the above method, the irradiation light amount of the measurement light beam irradiating the surface of the measurement object (2) and the light reception amount received by the light receiving unit (9) are represented by Lambert's cosine. A diffuse reflection coefficient deriving means (14) for obtaining a diffuse reflection coefficient of the surface of the object to be measured in conformity with the law, and a color information determining means (15) for determining color information of the surface of the object to be measured (2). ) Three-dimensional shape measuring device.