Optical characteristic measuring device

Abstract

To provide an optical characteristic measuring device that can evaluate optical characteristics of a sample without processing the sample, such as cutting the sample, and can facilitate the evaluation of the optical characteristics of the sample.SOLUTION: An optical characteristic measuring device includes light irradiation means 1 that irradiates a sample W with light, holding means 4 that can arbitrarily change the irradiation angle of the light irradiated to the sample W, reflection means 5 that has a reflector portion 5a formed around the sample W and reflects light reflected from or transmitted through the sample W in one direction by the reflector portion 5a, detection means 6 that can detect the light reflected by the reflector portion 5a of the reflection means 5, and evaluation means 7 that can obtain and evaluate a bidirectional reflectance distribution function (BRDF) based on the light detected by the detection means 6, wherein the reflection means 5 has a flat bottom surface 5c that can be placed on the sample W, and has an opening 5d in the center to allow the sample W to face the reflector portion 5a.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an optical characteristic measuring apparatus capable of evaluating the optical characteristics of a sample based on light detected by a detection means. [Background technology]

[0002] Conventionally, an optical property measuring device capable of evaluating optical properties such as the bidirectional reflectance distribution function (BRDF) and the bidirectional transmittance distribution function (BTDF) by irradiating a sample with light, causing it to reflect or transmit, and detecting the reflected or transmitted light, is disclosed, for example, in Patent Document 1. Such a conventional optical property measuring device uses a cone-shaped reflecting mirror part to irradiate light onto the sample and detects the reflected or transmitted light, making it possible to measure the optical properties of the sample surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2007-508532 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned conventional technology, when evaluating the optical characteristics of, for example, a road surface or a building frame, the road surface or frame must be cut into small pieces to prepare samples and positioned at the center of the reflector, which makes it extremely difficult to evaluate the optical characteristics. Also, there is a problem that it is difficult to evaluate the optical characteristics of the road surface or building frame when the surface is wet with rainwater or the like.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide an optical property measuring device that can evaluate the optical properties of a sample without processing the sample by cutting or the like, and that can easily perform the evaluation work of the optical properties of the sample. [Means for solving the problem]

[0006] The invention described in claim 1 is an optical property measuring device comprising: light irradiating means for irradiating light towards a sample and causing it to be reflected or transmitted by the sample; holding means for holding the light irradiating means and capable of arbitrarily changing the irradiation angle of light irradiated from the light irradiating means to the sample; reflecting means having a reflecting mirror portion formed around the sample and reflecting the light reflected from or transmitted through the sample in one direction by the reflecting mirror portion; detecting means for detecting the light reflected by the reflecting mirror portion of the reflecting means; and evaluating means for evaluating the optical properties of the sample based on the light detected by the detecting means, wherein the reflecting means has a flat bottom surface so that it can be placed on the sample and has an opening in the center so that the sample faces the reflecting mirror portion.

[0007] The invention described in claim 2 is characterized in that, in the optical property measuring device described in claim 1, the holding means is formed with a plurality of holding parts capable of holding the light irradiating means at angles different from each other, and the light irradiation angle can be arbitrarily changed by arbitrarily selecting the holding part to hold the light irradiating means.

[0008] The invention described in claim 3 is characterized in that, in the optical property measuring device described in claim 2, the holding means is extended and curved upward from the side of the reflecting means and is fixed to the reflecting means.

[0009] The invention described in claim 4 is characterized in that, in the optical property measuring device described in claim 3, the reflecting means has a notch portion in a part of the reflecting mirror portion, and the fitting portion of the holding means is fitted into and fixed to the notch portion.

[0010] The invention described in claim 5 is characterized in that, in the optical property measuring device described in claim 1, the evaluation means uses a learning model obtained by performing machine learning to evaluate the optical properties using accumulated data, which is a set of multiple pieces of data regarding the evaluation of the optical properties when the irradiation angle of the light irradiated from the light irradiation means to the sample is arbitrarily changed, as teacher data, and evaluates the optical properties based on the light detected by the detection means. Effect of the Invention

[0011] According to the invention of claim 1, the reflecting means has a flat bottom surface so that it can be placed on a sample, and has an opening in the center so that the sample faces the reflecting mirror portion. Therefore, the optical characteristics can be evaluated by placing the reflecting means on the sample and irradiating the sample facing the opening with light, which makes it possible to evaluate the optical characteristics without processing the sample and facilitates the evaluation of the optical characteristics of the sample.

[0012] According to the invention of claim 2, the holding means is formed with a plurality of holding portions capable of holding the light irradiating means at angles different from each other, and the light irradiation angle can be arbitrarily changed by arbitrarily selecting a holding portion to hold the light irradiating means, so that the irradiation angle of light from the light irradiating means can be easily changed.

[0013] According to the invention of claim 3, the holding means is extended while curving upward from the side of the reflecting means and is fixed to the reflecting means. This makes it possible to prevent the relative position of the holding means with respect to the reflecting means from shifting, and enables the irradiation angle of light from the light irradiation means to be changed with high precision.

[0014] According to the invention of claim 4, the reflecting means has a notch portion in a part of the reflecting mirror portion, and the fitting portion of the holding means is fitted into and fixed to the notch portion, so that the irradiation angle of the light from the light irradiating means can be changed over a wide range.

[0015] According to the invention of claim 5, the evaluation means uses a learning model obtained by performing machine learning to evaluate the optical properties using, as teacher data, accumulated data that has been accumulated to evaluate the optical properties when the irradiation angle of the light irradiated from the light irradiation means to the sample is arbitrarily changed, and evaluates the optical properties based on the light detected by the detection means, so that the optical properties can be evaluated using AI (artificial intelligence) techniques. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic diagram showing an overall configuration of an optical property measuring device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a perspective view showing the optical characteristic measuring device as viewed from below. [Diagram 3] FIG. 1 is a perspective view showing a state in which the optical characteristic measuring device is placed on a sample. [Figure 4] Cross-sectional view of line IV-IV in Figure 3 [Diagram 5] FIG. 11 is a cross-sectional view showing a state in which the light irradiating means in the optical characteristic measuring device is held in another holding hole of the holding means and irradiated with light. [Figure 6] FIG. 13 is a cross-sectional view showing a state in which the light irradiating means in the optical characteristic measuring device is held in another holding hole of the holding means and irradiated with light. [Figure 7] FIG. 2 is a perspective view showing a light irradiation means in the optical characteristic measuring device. [Figure 8] FIG. 2 is a perspective view showing a state in which the holding means and the reflecting means in the optical characteristic measuring apparatus are viewed from above. [Figure 9] FIG. 2 is a perspective view showing the holding means and the reflecting means in the optical characteristic measuring device as viewed from below. [Figure 10] FIG. 3 is a three-dimensional view showing the holding means and the reflecting means in the optical characteristic measuring device. [Figure 11] Cross section of line XI-XI in Figure 10 [Figure 12] FIG. 2 is an exploded perspective view showing a state in which the holding means is detached from the reflecting means in the optical characteristic measuring device. [Figure 13] FIG. 13 is a side view showing an optical characteristic measuring apparatus according to another embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The optical property measuring device of this embodiment is capable of evaluating the optical properties of a sample based on light detected by a detection means, and as shown in Figures 1 to 6, is configured to include a light irradiation means 1 capable of irradiating light from a light source 2, a holding means 4 for holding the light irradiation means 1, a reflection means 5 for reflecting light reflected from the sample W, a detection means 6 capable of detecting the reflected light from the reflection means 5, and an evaluation means 7 for evaluating the sample W based on the reflected light detected by the detection means 6.

[0018] 7, the light irradiation means 1 is connected to a light source 2 having a light emitting diode (LED) 2a via an optical fiber 3, and is configured to have a light irradiation surface 1a and a held portion 1b that can be engaged and held in the holding holes (4a to 4f) of the holding means 4. The light emitting diode 2a is capable of emitting light when power is supplied, and the emitted light is guided to the light irradiation means 1 via the optical fiber 3.

[0019] The holding means 4 holds the light irradiating means 1 and can arbitrarily change the irradiation angle of the light irradiated from the light irradiating means 1 to the sample W. In this embodiment, a plurality of holding holes (4a to 4f) (holding portions) capable of holding the light irradiating means 1 at angles different from one another are formed, and the light irradiation angle can be arbitrarily changed by arbitrarily selecting one of the holding holes (4a to 4f) to hold the light irradiating means 1.

[0020] Specifically, the holding means 4 is curved and extended upward from the side of the reflecting means 5, and is fixed to the reflecting means 5, with holding holes 4a, 4b, 4c, 4d, 4e, and 4f formed in that order from bottom to top. When the light irradiating means 1 is held in the holding hole 4a and light is irradiated, the irradiated light is reflected at the smallest angle with respect to the surface of the sample W, and is further reflected by the reflecting mirror portion 5a to reach the detecting means 6, as shown in FIG.

[0021] Furthermore, for example, when the light irradiating means 1 is held in the holding hole 4c and irradiated with light, as shown in Fig. 5, the irradiated light is reflected at a predetermined angle by the surface of the sample W, and is further reflected by the reflecting mirror portion 5a to reach the detecting means 6, and when the light irradiating means 1 is held in the holding hole 4e and irradiated with light, as shown in Fig. 6, the irradiated light is reflected at a predetermined angle by the surface of the sample W, and is further reflected by the reflecting mirror portion 5a to reach the detecting means 6. The same applies to the other holding holes 4b, 4d, and 4f.

[0022] That is, the holding means 4 according to this embodiment can arbitrarily select the holding holes (4a to 4f) to hold the light irradiating means 1, thereby arbitrarily changing the irradiation angle (incident angle) of light with respect to the surface of the sample W. As a result, by holding the light irradiating means 1 in sequence in the holding holes (4a to 4f) and irradiating light, it is possible to obtain detection values ​​of light at a plurality of irradiation angles (six in this embodiment).

[0023] 8 to 11, the reflecting means 5 is made of a cylindrical member facing the sample W at its center, and has a reflecting mirror portion 5a formed in a cone shape around the sample W on its inner circumferential surface, and reflects the light reflected from the sample W in one direction (specifically, the direction toward the lens portion 6a of the detecting means 6) by the reflecting mirror portion 5a. In other words, since the reflecting mirror portion 5a is formed in a cone shape around the sample W, it can receive the light diffused radially from the sample W toward the periphery and reflect it toward the lens portion 6a of the detecting means 6.

[0024] Here, the reflecting means 5 according to this embodiment has a flat bottom surface 5c so that it can be placed on the sample W, and has an opening 5d in the center so that the sample W faces the reflecting mirror portion 5a. When evaluating the optical characteristics of the sample W, as shown in Figures 4 to 6, the reflecting means 5 is placed on the sample W by abutting the bottom surface 5c against the surface of the sample W, and the light irradiating means 1 is held in any of the holding holes (4a to 4f), and then the light emitting diode 2a of the light source 2 is made to emit light and the light is irradiated from the irradiation surface 1a of the light irradiating means 1.

[0025] When light is irradiated from the light irradiating means 1 in this manner, the light is incident on the surface of the sample W facing the opening 5d at a predetermined irradiation angle (irradiation angle corresponding to the holding holes (4a to 4f)), reflected at a predetermined reflection angle (reflection angle corresponding to the incidence angle), and further reflected by the surrounding reflector section 5a to reach the detection means 6. Thereafter, by sequentially changing the holding holes (4a to 4f) that hold the light irradiating means 1 and irradiating light from the light irradiating means 1 each time, it is possible to obtain detection values ​​of light at a plurality of irradiation angles and reflection angles.

[0026] Furthermore, the reflecting means 5 according to this embodiment has a notch K in a part of the reflecting mirror portion 5a (a predetermined portion extending from the reflecting mirror portion 5a to the side wall surface 5b) as shown in Fig. 12, and the fitting portion F of the holding means 4 is fitted into and fixed to the notch K as shown in Figs. 8 to 11. This allows the holding holes (4a to 4c) to be formed within the height dimension of the reflecting mirror portion 5a as shown in Fig. 11, thereby widening the range of irradiation angles at which irradiation can be performed from the light irradiating means 1.

[0027] The detection means 6 is capable of detecting light reflected by the reflecting mirror portion 5a of the reflecting means 5, and is composed of, for example, an imaging means having a lens portion 6a. The detection means 6 according to this embodiment is fixed to the tip of a column portion H attached to the side wall surface 5b of the reflecting means 5, and is disposed above the opening 5d in the reflecting means 5 as shown in Figs. 4 to 6, so as to reliably receive the reflected light from the reflecting mirror portion 5a.

[0028] The evaluation means 7 is composed of a computer, such as a personal computer, connected to the input means 8 and the output means 9, and is capable of evaluating the optical characteristics of the sample W based on the light detected by the detection means 6. Specifically, a bidirectional reflectance distribution function (BRDF) can be obtained as a function of the irradiation angle on the surface of the sample W based on a plurality of reflected lights obtained by sequentially holding the light irradiation means 1 in the holding holes (4a to 4f) and irradiating light at a plurality of irradiation angles, and the obtained bidirectional reflectance distribution function (BRDF) can be output from the output means 9 as the optical characteristics of the sample W.

[0029] Such a bidirectional reflectance distribution function (BRDF) is composed of an index that represents the angular distribution characteristics of the reflected light when light is incident from a certain angle. In other words, the light that is radially diffused from the sample W toward the surroundings is diffused in all directions, and the diffused light has an angular dependency, which depends greatly on the surface condition and material of the sample W, so that the bidirectional reflectance distribution function (BRDF) specific to the sample W can be obtained.

[0030] In addition, the evaluation means 7 may use a learning model obtained by performing machine learning to evaluate optical characteristics using accumulated data that has been accumulated and that is a teacher data, and that relates to the evaluation of optical characteristics (BRDF, etc.) when the irradiation angle of light irradiated from the light irradiation means 1 to the sample W is arbitrarily changed, to evaluate the optical characteristics (BRDF, etc.) based on the light detected by the detection means 6.

[0031] Machine learning refers to a technology in which a computer learns a large amount of data and automatically constructs an algorithm or model that performs tasks such as classification and prediction, and a neural network, for example, can be used as a technology or algorithm that makes machine learning work. In the present embodiment, machine learning creates accumulated data by storing in advance a plurality (a large number) of data on a plurality of irradiation angles (incidence angles with respect to the sample W) and optical characteristics (BRDF, etc.) at each irradiation angle in a storage device such as a server.

[0032] The optical characteristics (BRDF, etc.) at a specific irradiation angle are input as teacher data to a computer for machine learning and are machine-learned. By using the learning model obtained by such machine learning, the evaluation means 7 can evaluate (predict) the optical characteristics based on the light detected by the detection means 6. The learning model can be input by the input means 8 and used by the evaluation means 7.

[0033] As a result, even if the light irradiating means 1 is held in a small number of holding holes (e.g., holding holes 4a, 4c, 4e) and light is irradiated, and the reflected light from the sample W is detected by the detection means 6, the optical characteristics (BRDF, etc.) can be obtained by utilizing AI (artificial intelligence) without holding the sample in other holding holes (e.g., holding holes 4b, 4d, 4f) and irradiating light. Therefore, there is no need to change many holding positions for the light irradiating means 1, and workability can be improved.

[0034] According to this embodiment, the reflection means 5 has a flat bottom surface 5c that allows it to be placed on the sample W, and has an opening 5d in the center so that the sample W faces the reflector portion 5a. Therefore, the reflection means 5 can be placed on the sample W and light can be irradiated onto the sample W facing the opening 5d to evaluate its optical characteristics (BRDF, etc.). This allows the optical characteristics to be evaluated without processing the sample W, and makes it easy to evaluate the optical characteristics of the sample W.

[0035] In particular, according to this embodiment, it is possible to efficiently generate BRDF data of objects in autonomous driving, and to obtain the BRDF of objects that are difficult to sample, such as road surfaces and building frameworks. Furthermore, according to this embodiment, it is possible to easily obtain BRDFs that have different road surface conditions, such as asphalt type, paint application, wear, rain or snow, etc.

[0036] Furthermore, the holding means 4 according to this embodiment is formed with a plurality of holding holes (4a to 4f) capable of holding the light irradiating means 1 at angles different from one another, and the light irradiation angle can be arbitrarily changed by arbitrarily selecting one of the holding holes (4a to 4f) to hold the light irradiating means 1, so that it is possible to easily change the irradiation angle of light from the light irradiating means 1. Note that instead of the holding holes (4a to 4f), other forms of holding parts (locking parts, etc.) capable of holding the light irradiating means 1 may be used.

[0037] Furthermore, since the holding means 4 according to this embodiment is provided extending while curving upward from the side of the reflecting means 5 and is fixed to the reflecting means 5, it is possible to prevent the relative position of the holding means 4 with respect to the reflecting means 5 from being shifted, and it is possible to change the irradiation angle of the light from the light irradiating means 1 with high precision. Also, the reflecting means 5 has a notch portion K in a part of the reflecting mirror portion 5a, and the fitting portion F of the holding means 4 is fitted into the notch portion K and fixed, so that the irradiation angle of the light from the light irradiating means 1 can be changed over a wide range.

[0038] Furthermore, the evaluation means 7 uses a learning model obtained by performing machine learning to evaluate the optical properties using teacher data that is a collection of multiple pieces of accumulated data relating to the evaluation of the optical properties when the irradiation angle of the light irradiated from the light irradiation means 1 to the sample W is arbitrarily changed, and evaluates the optical properties based on the light detected by the detection means 6, making it possible to evaluate the optical properties using AI (artificial intelligence) techniques.

[0039] Although the present embodiment has been described above, the present invention is not limited to this, and for example, as shown in Fig. 13, the holding means 4 may be turned upside down and attached to the reflecting means 5 to transmit light through the sample W, and the bidirectional transmittance distribution function (BTDF) relating to the transmission characteristics of the sample W may be obtained by the evaluation means 7. Furthermore, the evaluation means 7 may obtain various optical characteristics (surface characteristics) of the sample W that are different from the bidirectional reflectance distribution function (BRDF) and the bidirectional transmittance distribution function (BTDF). [Industrial Applicability]

[0040] The present invention can also be applied to devices with different external shapes or devices with added functions, etc., so long as they have the same gist as the present invention. [Explanation of symbols]

[0041] 1 Light irradiation means 1a Irradiation surface 1b Holding part 2 light source 2a Light Emitting Diode (LED) 3. Optical Fiber 4 Holding means 4a~4f Holding hole (holding part) 5 Reflection means 5a Reflector section 5b Side wall 5c Bottom 5d opening 6. Detection Methods 6a Lens section 7. Evaluation methods 8 Input Methods 9 Output Method H pillar part F Inset part K Notch

Claims

1. A light irradiation means for irradiating light toward the sample and causing the light to be reflected or transmitted by the sample; a holding means for holding the light irradiating means and capable of arbitrarily changing the irradiation angle of the light irradiated from the light irradiating means to the sample; a reflecting means having a reflecting mirror portion formed around the periphery of the sample, and reflecting light reflected or transmitted from the sample in one direction by the reflecting mirror portion; a detection means capable of detecting light reflected by a reflecting mirror portion of the reflecting means; an evaluation means capable of evaluating optical characteristics of the sample based on the light detected by the detection means; An optical characteristic measuring apparatus comprising:

4. An optical characteristic measuring apparatus comprising: said reflecting means having a flat bottom surface capable of being placed on said sample; and said reflecting means having an opening in the center for allowing said sample to face said reflecting mirror portion.

2. 2. The optical characteristic measuring device according to claim 1, wherein the holding means is formed with a plurality of holding portions capable of holding the light irradiating means at angles different from each other, and the light irradiation angle can be arbitrarily changed by arbitrarily selecting one of the holding portions to hold the light irradiating means.

3. 3. An optical characteristic measuring device according to claim 2, wherein said holding means is curved and extends upward from a side of said reflecting means and is fixed to said reflecting means.

4. 4. The optical characteristic measuring device according to claim 3, wherein said reflecting means has a notch in a part of said reflecting mirror portion, and said fitting portion of said holding means is fitted into said notch and fixed.

5. The optical property measuring device according to claim 1, characterized in that the evaluation means uses a learning model obtained by performing machine learning to evaluate the optical properties using teacher data, which is accumulated data relating to the evaluation of the optical properties when the irradiation angle of the light irradiated from the light irradiation means to the sample is arbitrarily changed, and evaluates the optical properties based on the light detected by the detection means.

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