WO2015093115A1 - Scattered-light-information processing method, scattered-light-information processing device, and scattered-light-information processing system - Google Patents

Abstract

This scattered-light-information processing method includes the following steps: a scattered-light-measurement-information acquisition step in which information regarding the intensity distribution of scattered light resulting from the scattering of light shone at a prescribed angle is acquired; a model generation step (step S202) in which a target-object model is generated from the geometry and optical properties of a target object, namely a transmissive optical element (300), and conditions under which the intensity distribution of the aforementioned scattered light was measured; a function-parameter setting step (step S203) in which, in the target-object model, a parameter for a function that represents information regarding output-side scattered light that has passed through the target object, at least, is set; a scattered-light-intensity-distribution computation step in which a scattered-light-intensity-distribution calculation result is computed on the basis of the target-object model; and function-parameter-computation processing steps (steps S204 through S207) in which the aforementioned function parameter is computed such that the scattered-light-intensity-distribution calculation result computed on the basis of the target-object model matches the scattered-light-intensity-distribution information acquired in the scattered-light-measurement-information acquisition step.

Description

Scattered light information processing method, scattered light information processing apparatus and scattered light information processing system

The present invention relates to a scattered light information processing method and scattered light information processing apparatus for acquiring scattered light information necessary for performing optical design simulation with optical design software used in a camera, an endoscope, a microscope, etc. And a scattered light information processing system.

The optical design software sets, as parameters, r (curvature radius), d (surface distance), n (refractive index) of each optical element contained in the lens frame, and the reflectance and transmittance of the coat. It then calculates the refraction and reflection of various rays propagating in the optical system.

In optical design, each parameter is modified to meet the desired optical performance at the image plane. In addition, for the lens frame manufactured, the optical performance can be estimated by acquiring and setting the respective parameters by measurement.

The optical design software can evaluate not only spot diagrams and MTF (Modulation Transfer Function) on the image plane, wavefront aberrations, but also unnecessary light such as ghosts and flares as evaluation of optical performance.

Ghost and flare are phenomena that occur when unnecessary light other than normal light reaches the image plane. The cause of ghosts and flares is not only multiple reflections on each optical surface and incident of unexpected light, but also lens surfaces and surfaces after anti-reflection coating, lens ridges after chamfering, chamfers and edges Also, it is conceivable that scattered light is generated due to the surface inside the lens frame being rough, and the scattered light becomes unnecessary light.

Therefore, when evaluating ghosts and flares in the optical design simulation, it is necessary to accurately input the scattered light intensity distribution which is the scattered light information of each surface in addition to the normal parameters. Then, when scattered light information is input, in each optical surface, ray tracing by Monte Carlo method is performed in addition to geometrical optical ray tracing, and a ray reaching the image plane is calculated.

Scattered light information is generally represented using a bi-directional scattering distribution function (hereinafter referred to as “BSDF” as appropriate) or a parameter called ARS obtained by dividing the Cos θ component from the BSDF.

As shown in FIG. 12, for the light L incident on the measurement surface 10, scattered light Sc reflected from the measurement surface 10 of the object to be measured and scattered light Sc transmitted through the measurement surface 10 are generated. The scattered light reflected by the measurement surface 10 of the object to be measured is referred to as Bidirectional Reflectance Distribution Function (hereinafter referred to as “BRDF” as appropriate). Further, the scattered light transmitted through the measurement surface 10 of the object to be measured is referred to as a Bidirectional Transmittance Distribution Function (hereinafter referred to as “BTDF” as appropriate).

And, BSDF is defined as scattered light including both BRDF and BTDF.

As an apparatus and method for obtaining scattered light information reflected from an object to be measured, for example, the one disclosed in Patent Document 1 below is known.

Patent No. 5058838

However, the apparatus and method described in Patent Document 1 are for acquiring scattered light information reflected from an object to be measured of an impermeable material with higher accuracy. That is, in the prior art, scattered light information can not be obtained for an object to be measured having a transmissive portion such as an optical element.

The present invention has been made in view of the above, and it is possible to obtain scattered light information of an optical element having a transmission part as an object to be measured with high accuracy, a scattered light information processing method, a scattered light information processing apparatus and scattered light The purpose is to provide an information processing system.

In order to solve the problems described above and achieve the purpose, the scattered light information processing method of the present invention is
A scattered light information processing method for processing scattered light information of an object to be measured, comprising:
The object to be measured is an optical element composed of a substance at least a part of which transmits light,
A scattered light measurement information acquiring step of acquiring information of a scattered light intensity distribution of light irradiated at a predetermined angle with respect to an object to be measured;
A model generation step of creating an object model from the measurement conditions of the shape and optical properties of the object to be measured and the scattered light intensity distribution;
A function parameter setting step of setting a parameter of a function representing at least scattered light information on the output side transmitted through the object to be measured with respect to the object model;
A scattered light intensity distribution calculating step of calculating a scattered light intensity distribution calculation result by calculation based on an object model;
Function parameter calculation that calculates function parameters so that the information of the scattered light intensity distribution acquired in the scattered light measurement information acquisition process and the scattered light intensity distribution calculation result calculated by calculation based on the object model match Processing steps,
It is characterized by having.

Further, the scattered light information processing apparatus of the present invention is
A scattered light information processing apparatus for processing scattered light information of an object to be measured, comprising:
The object to be measured is an optical element composed of a substance at least a part of which transmits light,
A scattered light measurement information acquisition unit that acquires information of a scattered light intensity distribution of light irradiated to a measured object at a predetermined angle;
A model generation unit for creating an object model from the measurement conditions of the shape and optical properties of the object to be measured and the scattered light intensity distribution;
A function parameter setting unit configured to set a parameter of a function representing at least scattered light information on an output side transmitted through the object to be measured with respect to the object model;
A scattered light intensity distribution calculation unit that calculates a scattered light intensity distribution calculation result by calculation based on an object model;
Function parameter calculation that calculates function parameters so that the information of the scattered light intensity distribution acquired by the scattered light measurement information acquisition unit and the scattered light intensity distribution calculation result calculated by calculation based on the object model match A processing unit,
It is characterized by having.

In the scattered light information processing system of the present invention,
A scattered light information processing system that measures scattered light of an object to be measured and processes scattered light information,
The object to be measured is an optical element composed of a substance at least a part of which transmits light,
A light irradiation unit that irradiates light at a predetermined angle with respect to the object to be measured;
A scattered light measurement unit that receives at least light scattered by the object to be measured;
A scattered light measurement information acquisition unit that acquires information on the scattered light intensity distribution of the object based on the information received by the scattered light measurement unit;
An information storage unit that stores the shape and optical properties of the object to be measured and the measurement conditions of the scattered light intensity distribution;
A model generation unit that generates an object model from the stored shape, optical properties, and measurement conditions;
A function parameter setting unit configured to set a parameter of a function representing at least scattered light information on an output side transmitted through the object to be measured with respect to the object model;
A scattered light intensity distribution calculation unit that calculates a scattered light intensity distribution calculation result by calculation from an object model;
Function parameter calculation processing unit that calculates function parameters so that the information of the scattered light intensity distribution acquired by the scattered light measurement information acquisition unit and the scattered light intensity distribution calculation result calculated by calculation from the object model match When,
It is characterized by having.

According to the present invention, it is possible to obtain scattered light information with high accuracy even when the object to be measured is a transparent substance.

FIG. 1A is a functional block diagram showing an overview of a scattered light information processing system according to a first embodiment of the present invention. Further, FIG. 1B is a functional block diagram for explaining the scattered light information processing system in more detail. It is a flowchart explaining the measuring method of the scattered light in 1st Embodiment. It is a figure which shows schematic structure of the scattered light information processing system of BSDF. It is a flowchart explaining a data processing method. It is a figure which shows intensity distribution of the scattered light in case the scattering of the surface of to-be-measured object is small. (A), (b) is a figure which shows the measurement range of scattered light. It is a functional block diagram which shows the outline | summary of the scattered light information processing system of 2nd Embodiment of this invention. It is a figure which shows the drive state of a light irradiation part and a light-receiving part. It is a flowchart explaining the measuring method of the scattered light in 2nd Embodiment. It is a flowchart explaining the data processing method in 2nd Embodiment. It is a flowchart explaining the data processing method of the modification of a 2nd embodiment. It is a figure explaining scattered light information. It is a figure explaining a parameter. (A), (b) is a figure explaining reflection of light. It is another figure explaining a scattered light.

Hereinafter, embodiments of a scattered light information processing method, a scattered light information processing device, and a scattered light information processing system according to the present invention will be described in detail based on the drawings. The present invention is not limited by this embodiment.

First, based on the prior art, scattered light information and measurement will be described in more detail on the premise of describing the embodiment of the present invention.

The BSDF of the scattered light information represents the radiance of the scattered light as a function of the angle of the scattered light from the surface normal, and in some cases as a function of the angle of the incident light illuminating the scattering surface. Specifically, for example, BRDF of BSDF is defined by the following equation 1.

FIG. 13 shows the symbol of equation 1 and parameters shown using an XYZ orthogonal coordinate system, for example, when light is irradiated to the surface of the opaque material. As shown in FIG. 13, the incident light ray angle (θ _i ), the incident azimuth angle (φ _i ), the light reception angle (θ _r ), the light reception azimuth angle (φ _r ), and the wavelength (λ) of the incident light It is given by a variable. P _i indicates the light intensity of the incident light, and P _r indicates the light intensity of the reflected light of the measurement area dA of the measurement surface. Also, dω _i and dω _r represent solid angles.

The BSDF is a scattered light intensity distribution of a plane by definition, regardless of the relationship between a substance to be measured and a transmitting material and a non-transmitting material, and the outer shape and the optical properties of the material to be measured are not considered. That is, when the object to be measured is a permeable substance, the influence of the front and back surface shape (spherical surface, aspheric surface, free curved surface etc.), outer diameter, surface distance (thickness), ridges, chamfers, edges, refractive index etc. Is not considered. BSDF represents the behavior of scattered light generated by one plane.

By defining BSDF in this way, it becomes possible to input it as a surface parameter to optical design software, and perform accurate optical design simulation even if other input parameters such as curvature radius and surface spacing are changed. be able to.

FIG. 3 shows a schematic configuration of a scattered light information processing system of BSDF when using a parallel flat plate 300 of a transmissive material as an object to be measured. In the coordinate system, in the XYZ orthogonal coordinate system which is orthogonal coordinates, the vertical direction is taken as the Y-axis direction, the direction parallel to the incident light in the horizontal direction as the Z-axis direction, and the direction orthogonal thereto in the horizontal direction as the X-axis direction.
Here, the reason why a parallel plane is used for the object to be measured 300 is to eliminate in advance the influence of the front and back surface shapes of the object to be measured as much as possible.

In addition, the parallel flat plate 300 of the object to be measured often has a surface roughness to be measured on one side 300a, for example, a desired roughness approximate to the surface of a lens, a convex portion, a chamfer or the like.
By using such an object to be measured, the relationship between the surface roughness and the scattered light intensity distribution can be measured.

The light irradiation unit 101 uses a laser or a white light source that emits light having a predetermined wavelength. And the light from the light irradiation part 101 injects into the parallel flat plate 300 which is a to-be-measured object at a predetermined angle. The incident light scatters on the roughened surface of the parallel flat plate 300, which is the object to be measured, passes through the object to be measured, and is emitted to the air.

The light receiving unit 102 obtains the intensity distribution of the scattered light two-dimensionally or three-dimensionally with respect to the light emitted from the parallel flat plate 300 centering on the measurement surface 300 a of the object to be measured. The light receiving unit 102 can be moved to, for example, the position A, the position B, and the like by the driving unit 305. By the above, it is possible to obtain BSDF which is the transmission and reflection scattered light intensity distribution.

When the object to be measured is an opaque material, only BRDF which is a scattered light intensity distribution of reflection can be acquired.

When the BSDF acquired as described above is input as a parameter to the optical design software, an error occurs when the object to be measured deviates from the definition of the BSDF.
For example, when the object to be measured is a non-transparent material and BRDF is acquired, in the prior art, when the surface of the object to be measured is other than a flat surface, the measurement result of the scattered light intensity distribution by the scattered light information processing system is BRDF. The influence of the surface shape of the surface is included, resulting in an error.

Therefore, in the prior art, BRDF excluding the influence of the surface shape is calculated using the information of the measurement result of the scattered light intensity distribution and the surface shape information of the object to be measured.

FIG. 14A is a view for explaining the reflected light due to the geometrical optical component when the incident light Lin is incident on the measurement surface 10. The incident light Lin is reflected as reflected light Lref at the same angle as the incident angle with respect to the normal N to the tangent of the incident position.

FIG. 14B is a view for explaining the reflected light due to the wave-optical component when the incident light Lin is incident on the measurement surface 10 a.
As described in the prior art, when light is incident on the object to be measured, the scattered light intensity distribution is calculated from the combination of the surface shape information and the BRDF in the irradiation area of the measurement surface 10a. Then, the BRDF is changed so that the calculated scattered light intensity distribution approximates the actual scattered light intensity distribution measurement result. Thus, the BRDF is calculated separately from the influence of the surface shape in the irradiation area of the reflective surface.

However, as described above, in the prior art, when the object to be measured is a permeable substance, it can not be applied. It goes without saying that when the object to be measured is a transmissive substance, an error occurs when the measurement surface of the object to be measured is not flat in the irradiation area of the light from the light irradiation part. In addition, it receives the influence of the shape other than the irradiation area | region of the light from a light irradiation part, and the inside of a to-be-measured object. That is, when the object to be measured is a transparent substance, even if the measurement surface is a flat surface, an error occurs if the measurement result of the scattered light intensity distribution by the scattered light information processing system is BSDF. This is a problem specific to the case where the object to be measured is a permeable substance. Further details will be described below.

Here, I will describe the definition of BSDF again.
In the optical design software, as described above, the BSDF definition is a function of the angle of the scattered light from the surface normal. Also, sometimes the radiance of the scattered light is represented as a function of the angle of the incident light irradiating the scattering surface, and the scattered light intensity distribution on the plane is taken.

For this reason, the outer shape and optical properties of the object to be measured are not considered. That is, when the object to be measured is a permeable substance, the front and back surface shape (spherical surface, aspheric surface, free curved surface etc.), outer diameter, surface distance (thickness), ridges, chamfers, edges and refractive index of the object to be measured Since the influence of etc. is included, the result of simply measuring the scattered light deviates from the definition of BSDF.
As a result, according to the conventional procedure, BSDF can not be obtained for the object to be measured of the permeable substance. This will be described in more detail.

In the case where the object to be measured is a transmissive substance, a unique phenomenon when measuring scattered light will be described. FIG. 15 is a view for explaining the behavior of the scattered lights Sf and Scr of the parallel flat plate 20 having the transmission part on the object to be measured. In the parallel plate 20, first, the incident light Lin enters the first surface 20b before reaching the second surface 20a, which is a scattering surface, and transmits the inside of the parallel plate 20, which is an object to be measured. In addition, at the interface between the first surface 20b and the air, reflection occurs due to the difference in refractive index. Furthermore, light absorption and fluorescence occur inside the material of the parallel flat plate 20, and the light amount of the incident light Lin reaching the second surface 20a changes.

The scattered light flux Scr generated by the second surface 20a is such that light originally emitted backward (incident side) strikes the first surface 20b and causes refraction and total reflection at the interface between the air and the first surface 20b. A portion of the totally reflected light beam S1 travels in the forward direction. Also, a part of the refracted luminous flux S2 is emitted at a wide angle according to Snell's law. In this way, the behavior of the scattered light generated by one surface changes under the influence of the other surface.

Further, the light flux S1 and the light flux S2 are transmitted through the inside of the parallel flat plate 20 which is the object to be measured, and the influence of light absorption and fluorescence of the substance is added according to the traveling distance. It will change.

In particular, it can be seen that the larger the intensity and the spread angle of the scattered light generated by one surface, the higher the degree of influence on the measurement result. So far, although the object to be measured has been described for the parallel flat plate 20, when the first surface and / or the second surface is a curved surface like a lens, the behavior of light becomes more complicated, and the incident light Lin is initially The second surface reaches the second surface at an angle different from the incident angle to the first surface of the second surface, and the behavior of the backscattered light of the second surface changes under the influence of the surface shape of the first surface. These are all problems specific to the permeate.

Thus, while it is originally intended to measure the behavior of the scattered light generated by one side of the object to be measured, when the object to be measured is a transmitting material, not only the surface shape of the object to be measured but also the back surface Surface shape, outer diameter, surface spacing (thickness), outer shape of ridges, chamfers, edges, etc., and the influence of the inside of the measured object such as refractive index, transmittance, reflectance, light absorptance, fluorescence, etc. Becomes the scattered light intensity distribution.

As a result, when the object to be measured is a transmissive substance, the above-described conventional techniques can not consider the behavior of the scattered light inside the substance, and as a result, can not calculate BSDF. As described above, conventionally, in the transmissive material, even if the intensity distribution of the scattered light is measured, the result can not simply be used as BSDF which is a parameter of the optical design simulation. Also, even if it is used, an error occurs and accurate optical design simulation can not be performed.

The embodiment described below can solve the problem of the error contained in the scattered light intensity distribution measurement result of such a conventional transmitting material, and based on the scattered light intensity distribution measurement result BSDF which is a parameter to be input to the optical design simulation It can be calculated with high accuracy.

First Embodiment
Fig.1 (a) is a functional block diagram which shows the outline | summary of the scattered light information processing system 100 of 1st Embodiment of this invention. FIG. 1B is a functional block diagram for explaining the scattered light information processing system 100 in more detail.

As shown in FIG. 1A, the scattered light information processing apparatus 200 exchanges signals with the light emitting unit 101, the light receiving unit 102, and the information storage unit 103 via the control unit 110.

As shown in FIG. 1B, the scattered light information processing apparatus 200 includes a scattered light measurement information acquisition unit 104, a function parameter setting unit 105, a model generation unit 106, a scattered light intensity distribution calculation unit 107, and a function. And a parameter calculation processing unit 108.

In FIG. 1B, the scattered light information processing apparatus 200 surrounded by a dotted line is connected to the light emitting unit 101, the light receiving unit 102, and the information storage unit 103 via the control unit 110 as described above. There is.

The scattered light measurement processing device 200 provided in the scattered light information processing system 100 of the present embodiment will be described in more detail.
Here, the object to be measured is an optical element composed of a material at least a part of which transmits light. The optical element is, for example, a parallel plate 300 shown in FIG.

In FIG. 1B, the scattered light information processing apparatus 200 includes a scattered light measurement information acquisition unit 104 for acquiring information on the scattered light intensity distribution of light irradiated at a predetermined angle with respect to the object to be measured; Scattering reflected on the incident side of the measurement surface of the optical element with respect to the model generation unit 106 for creating an object model from the measurement conditions of the shape and optical properties of the object and the scattered light intensity distribution and the object model A function parameter setting unit 105 for setting parameters of a function representing light information and scattered light information on the outgoing side transmitted through the object to be measured, and scattered light to calculate the scattered light intensity distribution calculation result by calculation based on the object model The information of the scattered light intensity distribution acquired by the intensity distribution calculation unit 107 and the scattered light measurement information acquisition unit 104 agrees with the scattered light intensity distribution calculation result calculated by calculation based on the object model. Yo and a function parameter calculation unit 108 for calculating the function parameters.

Next, the configuration and components of the scattered light information processing system 100 according to the present embodiment will be described.

The scattered light information processing apparatus 200 is disposed integrally with the scattered light information processing system 100 or in one or another separate computer.

The control unit 110 controls the light emitting unit 101, the light receiving unit 102, and the information storage unit 103 in addition to the control of the scattered light information processing apparatus 200.

In the present embodiment, the light emitting unit 101 does not particularly define a laser diode (LD), a super luminescent diode (SLD), a light emitting diode (LED), a halogen as a white light source, and the like. Here, it is desirable that characteristics such as the wavelength of incident light, the polarization state, and the light intensity distribution be known.

The light receiving unit 102 moves continuously or intermittently in two or three dimensions centering on the measurement surface of the object based on the control information of the control unit 110 sent from the computer (not shown). It is a mechanism that can receive scattered light.

Here, the light receiving unit 102 is rotated around the measurement surface of the object to be measured. The present invention is not limited to this, and the light receiving unit 102 may be moved around another place different from the center of the object to be measured or a portion other than the object to be measured. The relative positional relationship between the rotation center position of the light receiving unit 102 and the position of the object to be measured may be known.

Further, the light receiving unit 102 has a mechanism capable of acquiring information of the scattered light transmitted through the object to be measured and / or the scattered light reflected.
Furthermore, the light receiving unit 102 is not particularly limited as long as it is a device such as a power sensor or a high sensitivity camera that can observe the intensity of light. Furthermore, it is desirable that the type of the light receiving unit 102 can be used properly depending on the light intensity and the angular resolution to be measured.
When it is desired to change the angle of incident light to the object to be measured, the light irradiation unit 110 or the object to be measured can be relatively changed in position.

The information storage unit 103 manages storage of “information of measurement condition”, “information of object to be measured” and “measurement information of scattered light”. A detailed description of the information of the measurement conditions and the information of the object will be described later.
As described above, the scattered light information processing apparatus 200 performs processing on scattered light information for calculating BSDF from "information of measurement conditions", "information of object to be measured", and "measurement information of scattered light". A detailed description of the processing of the scattered light information will be described later.

Thus, in addition to the scattered light information processing apparatus 200, the scattered light information processing system 100 that measures the scattered light of the object to be measured and processes the scattered light information further generates light at a predetermined angle with respect to the object to be measured. The light irradiation unit 101 for irradiating the light, the light reception unit 102 for receiving the scattered light transmitted through the object to be measured and / or the scattered light reflected from the object to be measured, and the measurement conditions of the shape and optical properties of the object to be measured and the scattered light intensity distribution And an information storage unit 103 to be stored.

Thereby, as described below, BSDF which is scattered light information of one surface, front and back surface shape, outer diameter, surface distance (thickness), ridge portion, chamfered portion, which is an outer shape of the object to be measured It can be calculated accurately by taking into consideration the influence of the inside of the object under test such as the edge part and the optical properties such as refractive index, transmittance, reflectance, light absorptivity, and fluorescence. . For this reason, when it sets as a parameter to optical design software, it becomes possible to simulate with high accuracy to the former.

Next, with reference to FIG. 2, a method of measuring scattered light in the present embodiment will be described.
The measurement by the scattered light information processing system 100 is started. In advance, in step S101, the measurement condition and information of the measurement condition are stored in the information storage unit 103a of the object under measurement via the control unit 110.

Information on measurement conditions includes the positional relationship between the light irradiation unit 101, the object to be measured, and the light receiving unit 102, the wavelength of incident light, the incident angle to the object to be measured, polarization state, NA (directivity), irradiation diameter, irradiation area It is information about detailed measurement such as internal intensity distribution, environment variable (external refractive index), temperature, atmospheric pressure, carbon dioxide concentration, etc.

At the same time, in step S101, the information storage unit 103a of the measurement condition and the object to be measured also stores information on the object to be measured. The information of the object to be measured includes front and back surface shape and shape which are outer shape, surface spacing (thickness), ridges, chamfers, edges and optical properties such as refractive index, transmittance, reflectance and light absorptivity In the case where an anti-reflection coating or the like is applied to an object to be measured such as a lens, fluorescence, and the like, it is a design requirement such as coating conditions. In particular, when the object to be measured is a transmissive substance, the setting of the optical properties described above is an essential requirement.

That is, it is desirable that the shape and optical properties of the object to be measured include at least the radius of curvature, the optical thickness, and the refractive index of the optical element as the object to be measured.

In addition, it is desirable that the information of the object to be measured be input in more detail. Thereby, the processing by the scattered light information processing apparatus 200 is performed with high accuracy.

The information on the object to be measured may be either information on a design formula or the like obtained from the drawing, or information on the result of actual measurement. In the information based on actual measurement, surface shape error of surface and back surface, surface distance error, eccentricity error, outer diameter error which is external shape error, refractive index distribution, reflectance, transmittance, light absorptivity, fluorescence, etc. The item etc. regarding the optical property of a measuring object etc. are mentioned.

The information on the measurement conditions and the information on the object to be measured are sent to the computer. Then, it is stored in the information storage unit 103a of the measurement condition and the object to be measured through the control unit 110 which is integrated with or separate from the computer.

Next, in step S102, measurement by the scattered light information processing system 100 is performed to obtain measurement information of scattered light. A state of receiving scattered light will be described by showing a specific system configuration.

The drive unit 305 shown in FIG. 3 moves the light receiving unit 102 based on the control information sent from the control unit 110 of the computer. In FIG. 3, the light receiving unit 102 selectively describes two states of position A and position B. The invention is not limited to this, and it goes without saying that the drive unit 305 can move the light receiving unit 102 to an arbitrary position, and when the object to be measured is the parallel flat plate 300, it can be continuously or two-dimensionally or three-dimensionally centered on the measurement surface 300a. It can move intermittently and receive scattered light from the surface to be measured. At this time, it is desirable that the fluorescence emitted from the object to be measured is removed by a filter or the like.

Then, the measurement information of the scattered light received by the light receiving unit 102 is sent to the computer, and stored in the scattered light intensity distribution measurement data storage unit 103 b via the control unit 110.
At this time, the measurement information of the scattered light may be sent collectively to the computer together with the information of the measurement conditions and the information of the object to be measured.

An information storage unit 103 (see FIG. 1A) is configured by the measurement condition and the information storage unit 103a of the object to be measured, and the scattered light intensity distribution measurement data storage unit 103b.
Here, it goes without saying that the contents of the measurement condition and the information storage unit 103a of the object to be measured and the scattered light intensity distribution measurement data storage unit 103b may be collectively stored in a text file or the like.

In addition, as a to-be-measured object, it is not restricted to a parallel plate, The lens element etc. which have a curved surface can also be measured.

Moreover, although the procedure was shown about the measuring method of scattered light information using FIG. 2, this order may be back and forth. For example, after measuring scattered light, information on the measurement conditions may be input in accordance with the measurement conditions. Further, after measuring the scattered light, information of the object to be measured may be obtained.

For example, when a contact-type shape measuring machine is used to obtain information on the shape of the object to be measured, the surface of the object to be measured may be scratched with the measurement probe. For this reason, the direction in which the shape measurement is performed after measuring the scattered light has an effect that the scattered light can be measured with high accuracy.

Next, a data processing method in the scattered light information processing apparatus 200 will be described.
FIG. 4 is a diagram for explaining a data processing method in the scattered light information processing apparatus 200. The scattered light information processing apparatus 200 performs predetermined processing using information on measurement conditions, information on an object to be measured, and measurement information on scattered light, and performs processing aiming to calculate BSDF with high accuracy.

First, the information processing unit 109 starts data processing. In step S201, a virtual measured object measurement simulation model is generated by the computer based on "information of measurement conditions" and "information of measured object". The object measurement simulation model in this state assumes that the light beam transmits and reflects the object under geometrical optics when passing the light beam through the object. In the following, in all the flowcharts, simulation is abbreviated as “Sim.” As appropriate.

In step S202, BSDF, which is scattered light information, is temporarily set on the surface to be measured of the object to be measured. As described above, BSDF is the angle (θ _i ) of incident light, the incident azimuth angle (φ _i ), the light reception angle (θ _r ), the light reception azimuth angle (φ _r ), and the wavelength (λ of incident light) It is given by five variables with). That is, the position of the BSDF on the three-dimensional space is expressed in two directions on the incident light side and in two directions on the light receiving side.

The distribution shape of the scattered light intensity can be fitted to model functions of several mathematical expressions. For example, as a model function, a Gaussian function, a Cos N power function, and a Lambertian function can be mentioned. Either function can express the scattered light intensity distribution as a function of angle. Here, the Gaussian model function will be described. The Gaussian function can be expressed by Equation 2 below.

The parameters θ and φ in the above equation 2 represent the angle of the scattered light intensity distribution. The parameters σ _θ and σ _φ indicate the half width of the Gaussian function. By changing the parameters, the distribution shape of each angular direction also changes.
P ₀ corresponds to the light intensity at the center. That is, for a certain incident angle (θ _i , φ _i ) of incident light, the scattered light intensity distribution can be represented by three parameters (variables) P ₀ , σ _θ , and σ _φ .

Various other functions can be set as model functions. For example, a Pearson 7 function known as a peak fit function, a Voight function, etc. can also be set.

Furthermore, for example, when the scattering of the surface is small as in an optical element, the light intensity distribution in the periphery is smaller than the light intensity distribution in the central portion. FIG. 5 is a diagram showing an intensity distribution of scattered light when scattering on the surface of the object to be measured is small. It is also possible to optionally create a model function such as the following Equation 3 suitable for such a scattered light intensity distribution. Here, α is a coefficient.

By selecting any of the above model functions, temporary setting of BSDF is performed. Returning to FIG. 4, the description will be continued. In step S203, initial values of parameters are set for temporary installation of the BSF of the specific measurement surface (specific surface) set in step 202. For example, when BSDF is a Gaussian function, initial values are set to three parameters P ₀ , σ _θ , and σ _φ . The initial value is appropriately set in accordance with the user's instruction and system requirements. In addition, it is more preferable if the range in which the parameter is changed, the change width, and the like can be simultaneously set.

In the present embodiment, the purpose is to calculate the scattered light intensity distribution for the transmissive substance as the object to be measured, so steps S202 and S203 are bi-directional transmittance distribution function (BTDF) and bi-directional reflectance which are BSDF. It must be set to both of the distribution functions (BRDF). The settings for BTDF and BRDF may be different or the same.

In step S204, ray tracing is performed by calculation processing of a computer on the virtual measured-object measurement simulation model set in steps S201 to S203. In ray tracing, since BSDF is set in step S202, ray tracing using random numbers such as Monte Carlo method is also performed in addition to normal geometrical ray tracing. Then, the scattered light intensity distribution of the object to be measured is calculated.

Here, in step S204, the movement of the scattered light will be described again using FIG.
In the ray tracing in step S204, when the incident light is incident on the surface to be measured of the object to be measured, backscattered light is generated. A part of the light beam S1 of this backscattered light is repeatedly reflected and totally reflected in the parallel flat plate 20 which is a transmitting material, and is incident on the surface to be measured again. In this internal reflection, it is seldom to be incident at the same angle as the incident angle of light by the light emitting unit. Scattering by light incident by backscattered light applies the concept of shift-invariant scattering angle, except for the Lambertian function.

The concept of shift invariant scattering angle is a calculation method that assumes that the shape of the scattered light intensity distribution does not change even when the incident angle changes. Details of the theory behind this process are described in James E. Harvey, "Light-Scattering Characteristics of Optical Surfaces" (doctoral dissertation, University of Arizona, 1976).

According to the shift-invariant scattering angle concept, the distribution shape of BSDF of light incident perpendicularly to the measurement surface of the object to be measured means the distribution shape of BSDF of light incident obliquely to the measurement surface the same. . Under such assumption, the scattered light intensity distribution can be calculated in step S204.

In step S205, the degree of coincidence at each angle of the scattered light intensity distribution is calculated using the scattered light intensity distribution calculated in step S204 and the "scattered light measurement information" stored in the information storage unit 103 of the computer. Do.

In calculating the degree of agreement of the values, the difference between the calculated scattered light intensity distribution and the measurement information of the scattered light is used to evaluate the value of P-V (Peak-Valley) value or RMS (Root-Mean-Square) value. I assume.

In step S206, the evaluation value calculated in step S205 is compared with a preset threshold value to determine whether the values match. If the evaluation value is larger than the threshold value, it is determined to perform processing to change the initial value of BSDF temporarily set in advance. When the evaluation value is smaller than the threshold value, it indicates that the set BSDF well represents the BSDF of the surface to be measured of the object to be measured.

If it is determined in step S206 that the evaluation value is larger than the threshold, that is, if the determination result is false (No), the process proceeds to step S207.
In step S207, the parameter of the initial value of BSDF is changed. Then, the process returns to step S204, and ray tracing is performed by arithmetic processing of the computer.

The processes from step S204 to step S207 are repeated until the evaluation value becomes smaller than the threshold. That is, convergence calculation is performed. Through these repeated steps, it is possible to calculate the parameters of BSDF which well represent BSDF of the surface to be measured of the object to be measured.

Here, even if the calculation is repeated, the evaluation value may not converge. In this case, there may be a case where the BSDF model function set in step S202 is different.
Therefore, if the evaluation value does not converge, the process returns to step S202, and the process of changing the BSDF model function is performed.

That is, when the evaluation value does not converge to the threshold value in the repetitive calculation from step S204 to step S207, the model function of the BSDF is changed in a step (not shown). Then, a new convergence calculation is added in which the step of changing the BSDF model function is repeatedly calculated from step S202.

If the determination result in step S206 is true (Yes), the data processing ends.
By the above processing, the model function of the BSF that best represents the scattered light information of the surface to be measured of the object to be measured and the parameters for determining the model function are determined.

In the example of the present embodiment, incident light is irradiated to the surface to be measured of the object to be measured. However, there is no particular limitation, and for example, the light may be incident on another part of the surface to be measured, or the entire object to be measured may be irradiated. It is needless to say that there is no particular restriction if it is clear how light is incident on the object to be measured.

As described above, according to the scattered light information processing system including the scattered light information processing apparatus and the scattered light information processing method for the scattered light information of the present embodiment and the apparatus and performing the method, the optical design of the transmissive material is performed. It becomes possible to obtain BSDF which is one of the parameters input to the software.

Then, in the optical design software, it is possible to perform an optical design simulation for ghosts and flares that occur when unnecessary light other than the regular light reaches the image plane.

Further, according to the present embodiment, in the transmitting material BSF, it is possible to obtain both the bidirectional transmittance distribution function (BTDF) and the bidirectional reflectance distribution function (BRDF).
Furthermore, according to the scattered light information processing method of the present embodiment, from the measurement result of scattered light, BSDF which is scattered light information of one surface, front and back surface shape and outer diameter which are the outer shape of the object to be measured (Thickness), ridges, chamfers, edges, and the effects of the optical properties such as refractive index, light absorptivity, fluorescence, etc., inside the object to be measured, and removing those effects, Accurately calculate BSDF. For this reason, when it sets as a parameter to optical design software, it becomes possible to simulate with high accuracy to the former.

In the present embodiment, a scattered light information processing apparatus for scattered light information, a scattered light information processing method for scattered light information, and a simplified scattered light information processing system including the apparatus and performing the method according to the shape of the object to be measured and the characteristics of BSDF. Or high precision is possible.

A method of realizing simplification and high precision will be specifically described. First, it is assumed that the following prediction conditions are satisfied.
The prediction condition is a scattered light intensity distribution having the same parameters as the model function of the scattered light intensity distribution shape of BTDF and BRDF, and being axially symmetrical with respect to incident light.

If the above prediction conditions are satisfied, the scattered light intensity distribution designated in step S202 of the flowchart of FIG. 4 has the same BTDF and BRDF model functions, and the measurement and calculation parameters can be reduced.
The prediction condition is that, of course, the object to be measured is a transmitting material, and the object to be measured is rotationally symmetric with respect to the incident light, and the incident light is perpendicularly incident on the surface to be measured. There is a premise to stand well.
In addition, the surface roughness is a model that holds accurately in the case of small irregularities having a wavelength equal to or less than the wavelength of the irradiation light.

As a specific example, Equation 4 shows a case where BTDF and BRDF are expressed using a Gaussian function as a model function.

Here, if it is set as axisymmetric scattered light intensity distribution, the following formula 5 is established.

Further, from the prediction condition that the parameters of BTDF and BRDF are the same, the following equations 6 and 7 hold.

That is, the real parameters are only P _t , P _r and σ. Further, the relationship between P _t and P _r is expressed by Equation 8 below. Here, x represents an item which does not contribute to scattering, such as a light absorption coefficient.

Here, L is the light intensity of the incident light, which is an essential input value in step S201 of the flowchart. Further, as described above, BTDF and BRDF are values generally normalized by the light intensity of incident light. Therefore, the parameter L can be set to one.

That is, in the scattered light measurement information acquisition unit 104, at least a scattered light intensity distribution transmitted through the object to be measured or a scattered light intensity distribution reflected from the object to be measured is normalized by the light intensity of incident light to the object to be measured It is desirable to obtain an intensity distribution.

Information acquisition of the scattered light intensity distribution may be either transmission or reflection normalized by incident light, and the other can be calculated from one. Therefore, only two parameters, P _t and σ, are finally calculated. That is, the processing time of the scattered light intensity distribution can be shortened. In addition, since the drive range of the light receiving unit only needs to be either transmission or reflection, the measurement apparatus can be simplified.

Furthermore, under the assumption based on the above prediction conditions, the scattered light intensity distribution in the forward direction is a scattered light intensity distribution that is axially symmetric with respect to the incident light. Therefore, as shown in FIG. 6A, the light receiving range of the light receiving unit may be measured in the range of 0 degrees to 90 degrees in the θ direction or the φ direction.

As described above, in the present embodiment, in the case of an object to be measured in which the conditions and the assumptions hold, the scattered light information processing apparatus, the measuring method, and the scattered light information processing method can be simplified. Alternatively, when measurement data in all directions have been acquired, it is possible to perform measurement processing with high accuracy by averaging measurement errors and noises by performing averaging processing.

Further, among the assumptions based on the above prediction conditions, when the model functions and the parameters of the scattered light intensity distribution shapes of BTDF and BRDF are different, the light receiving range of the light receiving part is θ direction or φ direction as shown in FIG. The range of 0 degrees to 180 degrees may be measured.

Second Embodiment
Next, a scattered light information processing device, a measurement method, a scattered light information processing method, and a scattered light information processing system according to the second embodiment will be described.
FIG. 7 is a functional block diagram showing a scattered light information processing system according to the second embodiment. Here, the configuration of the scattered light information processing apparatus 250 surrounded by a dotted line is different from that of the first embodiment.
In the scattered light information processing apparatus 250 of the second embodiment, the same components as those of the scattered light information processing apparatus of the first embodiment are denoted by the same reference numerals, and the redundant description will be omitted.

In the present embodiment, as shown in FIG. 7, the scattered light measurement information acquisition unit 104 acquires information on the scattered light intensity distribution of light irradiated to the object at a plurality of different incident angles.
Furthermore, the function parameter of each incident angle is used as a provisional function parameter so that the information of the scattered light intensity distribution acquired by the scattered light measurement information acquiring unit 104 matches the scattered light intensity distribution calculation result calculated from the object model Using the information of the scattered light intensity distribution acquired by the provisional function parameter calculator 251 and the scattered light measurement information acquiring unit 104 to be calculated, and at least a part of the provisional function parameters of each incident angle with respect to the object model The apparatus further includes a function parameter determination unit 252 that adjusts the provisional function parameters so as to match the calculated scattered light intensity distribution calculation result and determines a final function parameter.

Thereby, as described below, using scattered measurement information at a plurality of incident angles, BSDF which is scattered light information of one surface is not only the surface shape of the object to be measured but also the surface shape and outer diameter of the back surface , Spacing (thickness), external shape of ridges, chamfers, edges, etc., optical properties such as refractive index, transmittance, reflectance, light absorptivity, fluorescence, etc. Since the calculation can be performed in consideration, it is possible to calculate the scattering information with high accuracy from BSDF calculated using one incident angle. For this reason, when it sets as a parameter to optical design software, it becomes possible to simulate with high accuracy to the former.

Compared to the first embodiment, the method of measuring scattered light and the method of processing scattered light information are different. Specifically, in the second embodiment, the scattered light measurement method differs from the first embodiment in that measurement information of scattered light at each incident angle is obtained by changing a plurality of incident angles of incident light. . Furthermore, the method of processing scattered light information is different in that BSDF is calculated using measurement information of scattered light acquired by changing a plurality of incident angles of incident light.

Next, the configuration of the scattered light information processing system 150 will be described.
The scattered light information processing device 250 is disposed integrally with the scattered light information processing system 150 or in one or another separate computer.

The control unit 110 controls the light irradiation unit 101, the light receiving unit 102, and the information storage unit 103 in addition to the control of the scattered light information processing apparatus 250.
The information storage unit 103 manages storage of “information of measurement condition”, “information of object to be measured” and “measurement information of scattered light”. The scattered light information processing apparatus 250 performs control on scattered light information for calculating BSDF from “information of measurement condition”, “information of object to be measured”, and “measurement information of scattered light”.

The present embodiment has an effect that BSDF can be calculated with higher accuracy as compared with the above-described first embodiment.

Next, the procedure of the scattered light information processing method of the present embodiment will be described.
FIG. 9 is a flowchart illustrating the procedure of measuring scattered light in the scattered light information processing method according to the second embodiment.

In the present embodiment, in step S301 in FIG. 9, information of measurement conditions is set in the control unit 110 of the computer at the start of measurement by the scattered light information processing apparatus 250 as in the first embodiment. Here, in the second embodiment, with respect to the information stored in the first embodiment, the setting of the incident angle range of incident light and the number of divisions within the range are added as measurement condition information. It is set.

In the present embodiment, as shown in FIG. 8, the light emitting unit 101 and the light receiving unit 102 are driven by the driving unit 305 so as to change the relative position with respect to the object to be measured.

For example, a condition where the incident angle theta _i is determined by dividing by 5 degrees range 89 ° 0 ° (normal incidence) is set. Further, similarly to the first embodiment, the information of the object to be measured is also set at the same time.
The information on the measurement condition and the information on the object to be measured are sent to the computer and stored in the information storage unit 103a.

In step 302, based on the control information sent from the computer, the light receiving unit 102 moves in two dimensions and / or three dimensions centering on the measurement surface of the object to be measured, and receives scattered light from the measurement surface. Do.

Next, measurement information of the plurality of scattered lights received by the light receiving unit 102 is sent to the computer and stored in the scattered light intensity distribution measurement data storage unit 103 b.
Here, measurement information of scattered light in the measurement range (0 to 89 degrees) of the incident angle of incident light is represented as follows.

FS (θ _ni ) · · · ○ measurement data BS (θ _ni ) · · · △ measurement data

Here, FS indicates the scattered light intensity distribution in the forward direction with respect to the surface to be measured, and BS indicates the scattered light intensity distribution in the backward direction with respect to the object to be measured. Both FS and BS are functions of θ, θ _ni represents an incident angle of incident light to the surface to be measured, ni is ni = 1, 2, 3,..., Θ _ni = 0, 5, 10, It is assumed that 15, 20, ... 85.

In step S303, the incident angle of the incident light and information of measurement conditions set in advance are compared and determined. If the determination result in step S303 is true, the scattering measurement is ended.

If the determination result of step S303 is false, the process proceeds to step S304. In step S304, the incident angle of incident light is changed. Then, steps S301, S302, and S303 are repeated.

As described above, in the present embodiment, the measurement of S301 to S304 is repeated until the incident angle of the incident light to the object to be measured is acquired for the number of divisions within the predetermined range.
Here, the measurement information of the scattered light indicates a state when it is measured in one cross section in order to simplify the description. In other words, it is assumed that the incident angle of the incident light and the angle of the light receiving portion move only in the θ direction.
Next, in the computer, a predetermined process is performed in the scattered light information processing apparatus 250 using the above “information of measurement condition”, “information of object to be measured”, and “measurement information of scattered light”, BSDF is calculated.

A data processing method in the scattered light information processing apparatus 250 will be described. FIG. 10 is a flowchart for explaining the data processing method in the scattered light information processing apparatus 250. The scattered light information processing apparatus 250 performs processing intended to calculate BSDF.
The present embodiment is different from the above-described first embodiment in that “scattered light measurement information” measured at a plurality of incident angles is used.

The procedures of steps S401, S402, S403, S404, S405, S406, and S407 perform the same processes as steps S201, S202, S203, S204, S205, S206, and S207 in the flowchart of FIG. For this reason, duplicate explanations are omitted. In step S401, the incident angle of the measurement light is θ _ni . Then, the incident angle θ _ni is input from a small value (acute angle) with the measurement light.

In step S408, BSDF at a plurality of calculated incident angles is set as "provisional BSDF". Specifically, provisional BSDFs are calculated from ○ measurement data and △ measurement data, respectively.
Temporary BSDF (θ _ni ) (ni = 1, 2, 3,..., Θ _ni = 0, 5, 10, 15, 20, ... 85)

In step S409, it is determined whether the incident angle θ _ni is the largest angle. That is, it is determined that (temporarily) BSDF is calculated for all incident angles set in the measurement conditions.
If the determination result of step S409 is false (No), the process proceeds to step S410.

In step S410, the incident angle is changed to the next angle, and the processing from step S402 to step S408 is performed.

Next, after step S411, BSDF at each incident angle is calculated again. At this time, “temporary BSDF” calculated at each incident angle is set in the measurement object measurement simulation model, and calculation to calculate BSDF at each incident angle is performed again.

Here, in the present embodiment, the calculation accuracy is further improved as compared with the above-described first embodiment. The reason is explained.

The procedure of steps S401, S402, S403, S404, S405, S406, and S407 is the same processing as that of the first embodiment as described above. Here, the concept of shift invariant is applied to the calculation within the object to be measured.

Here, in practice, the scattered light intensity distribution differs depending on the incident angle to the object to be measured. In particular, it is known that the deviation from the idea of shift invariant increases as the incident angle increases.

Therefore, in steps S411 to S419, BSDF is determined using the provisional BSDF calculated at each incident angle without using the concept of shift invariant. The calculation accuracy is improved by recalculating in consideration of the scattered light intensity distribution at each incident angle as described above.

In step S411, temporary BSDFs at all calculated incident angles are set. In step S412, the scattered light intensity distribution is calculated.
In step S413, the scattered light intensity distribution calculated in step S412 is compared with the "scattered light measurement information" stored in the scattered light intensity distribution measurement data storage unit 103b of the computer. In step S414, the degree of coincidence of the scattered light intensity distribution at each angle is calculated and judged.

The calculation of the degree of coincidence uses the difference between the calculated scattered light intensity distribution at each angle and the measurement information of the scattered light. Then, a PV (Peak-Valley) value and an RMS (Root-Mean-Square) are used as evaluation values.

In step S414, the evaluation value calculated in step S412 is compared with a preset threshold value. In step S414, if the evaluation value is larger than the threshold value, that is, if the determination result is false, the process proceeds to step S415.

In step S <b> 415, processing for changing a provisional BSDF temporarily set in advance is performed in order from an angle with a small incident angle (acute angle). When the evaluation value is smaller than the threshold value, it indicates that the set temporary BSDF represents BSDF of the surface to be measured of the object to be measured with good accuracy.

If it is determined in step S414 that the evaluation value is larger than the threshold, the process proceeds to step S415. In step S415, a process of changing the parameters of temporary BSDF is performed. Then, the process returns to step S412, and ray tracing is performed.

The processes of steps S412, S413, S414, and S415 are repeatedly performed until the evaluation value becomes smaller than the threshold. That is, convergence calculation is performed.
Through the repeated steps, it is possible to calculate the parameters of the provisional BSF that well represent BSD of the surface to be measured of the object to be measured.

In step S416, it is determined whether the incident angle θ _ni is the largest angle using the new temporary BSDF determined in step S414. If the determination result in step S416 is false, in step S417, the temporary function parameter calculation unit 251 (FIG. 7) changes the incident angle θ _ni to the next angle to change the temporary BSDF at the next incident angle θ _ni. Set Then, after changing to the next angle, the processes of steps S411, S412, S413, S414, S415, S416, and S417 are performed.

If the determination result in step S416 is true, in step S418, the processing from step S411 to step S417 is repeated, and calculation is performed until the value of temporary BSDF at each incident angle converges. Then, in step S418, it is determined whether the tentative BSDF value has converged. The convergence judgment is made based on whether or not the change of each temporary BSDF is minimized.

If the determination result in step S418 is false, the process proceeds to step S419. In step S419, the function parameter determination unit 252 (FIG. 7) changes and determines the parameters of the BSDF function.

If the determination result in step S418 is true, the data processing ends. Through the above-described procedure, the model function of the BSF that best represents the scattered light information of the surface to be measured of the object to be measured and the parameters for determining the model function are determined.

According to the present embodiment, the scattered light information processing system 150, the scattered light information processing device 250 provided in the system 150, and the scattered light information processing method executed by the device 250 are input to the optical design software in the transmissive material. It becomes possible to obtain BSDF which is one of the parameters.

Then, in the optical design software, it is possible to perform an optical design simulation for ghosts and flares that occur when unnecessary light other than the regular light reaches the image plane.
Further, according to the present embodiment, in the transmitting material BSF, it is possible to obtain both the bidirectional transmittance distribution function (BTDF) and the bidirectional reflectance distribution function (BRDF).

Furthermore, according to the method of processing scattered light information of the present embodiment, BSDF which is scattered light information of one surface is not only the surface shape of the object to be measured, but also the surface shape and outer diameter of the back surface, and the spacing (thickness Bsf) correctly taking into consideration the influence of the inside of the test object such as refractive index, transmittance, reflectance, light absorptance and fluorescence which are the outer shape and optical properties such as ridges, chamfers, and edges, etc. It can be calculated. For this reason, when it sets as a parameter to optical design software, it becomes possible to simulate with high accuracy to the former.

(Modification of the second embodiment)
Next, a modification of the second embodiment will be described. FIG. 11 is a flowchart showing the procedure of the scattered light information processing method of the present modification.

The present modification differs from the second embodiment in that the measurement information of the scattered light at each incident angle is sequentially used to calculate the tentative BSDF. A data processing method in the scattered light information processing apparatus 250 will be described.

First, in steps S501 to S506, substantially the same processing as in steps S201 to S207 in the first embodiment is performed. The incident angle θ _ni is input from a small angle (acute angle).

In step S507, the BSDF calculated at the incident angle θ _ni is taken as a “provisional BSDF”.
In step S508, based on the information of the incident angle θ _ni of the incident light, it is determined whether the incident angle θ _ni is the largest angle. If the determination result of step S508 is false, the process proceeds to step S509.

In step S 509, the incident angle θ _ni of the measurement light is changed to the next angle using all of the temporary BSDF (θ _ni ) calculated up to this point. Then, the processing from step S501 to step S507 is performed.

Under the present circumstances, in step S504, temporary BSDF of the next incident angle is calculated using temporary BSDF calculated by then. That is, in the processing method of the measurement light information of the second embodiment, the tentative BSDF (θ _ni ) at each incident angle is calculated individually in step S402 to step S410.

On the other hand, in this modification, when calculating the tentative BSDF (θ _ni ), the estimated BSDF (provisional BSDF (θ _(ni-1) ) of the incident angle calculated up to the moment is calculated as the tentative BSDF (θ _{(ni The} point which is calculating the temporary BSDF of each incident angle in consideration of _{= 0)} )) differs.

As a result, by calculating in consideration of the scattered light intensity distribution at each incident angle, it is possible to obtain an effect that BSDF can be calculated with high accuracy. Furthermore, in the processing method of the measurement light information according to the second embodiment, it is possible to obtain the temporary BSDF calculated in consideration of the scattered light intensity distribution at each incident angle up to step S507. As a result, the processing from step S501 to step S509 can be streamlined, and the processing speed can be increased.

The above first and second embodiments have been described on the assumption that there is no place to generate the scattered light other than the measured surface of the object to be measured. The present invention is not limited to this, and there may be a plurality of places for generating scattered light other than the surface of the object to be measured.

With respect to the place to generate scattered light other than the measurement surface, BSDF may be calculated in advance by another method, and may be input as information of the measurement object. Also, it may be set as one of the calculation parameters in the repeated calculation.

Further, in the first and second embodiments, parallel flat plates are used as the object to be measured. It is needless to say that the present invention is not limited to this, and it is possible to measure even a sample of which both surfaces have a radius of curvature with a permeable material such as an imaging device such as a camera or an optical element used for an endoscope. In this case, the radius of curvature may be set in the information of the object to be measured in the information processing unit for the scattered light. When an antireflective coating or the like is applied to an object to be measured such as a lens, the coating conditions may be added to the information on the object to be measured. Furthermore, the present invention can be similarly applied to a flange portion, a chamfered portion, an edge portion and the like.

As described above, the present invention provides a scattered light information processing method, a scattered light information processing apparatus, and a scattered light information processing system capable of measuring the intensity distribution of scattered light of an optical element having a transmitting portion as an object to be measured with high accuracy. Is suitable.

100 scattered light information processing system 101 light irradiation unit 102 light receiving unit 103 information storage unit 104 scattered light measurement information acquisition unit 105 function parameter setting unit 106 model generation unit 107 scattered light intensity distribution calculation unit 108 function parameter calculation processing unit 110 control unit 200 Scattered light information processing device

Claims (24)

1. A scattered light information processing method for processing scattered light information of an object to be measured, comprising:
   The object to be measured is an optical element composed of a substance at least a part of which transmits light,
   A scattered light measurement information acquiring step of acquiring information of a scattered light intensity distribution of light irradiated to the object to be measured at a predetermined angle;
   A model generation step of creating an object model from the shape and optical properties of the object and the measurement conditions of the scattered light intensity distribution;
   A function parameter setting step of setting a parameter of a function representing at least scattered light information on an output side transmitted through the object to the object model;
   A scattered light intensity distribution calculating step of calculating a scattered light intensity distribution calculation result by calculation based on the object model;
   The function parameter is calculated such that the information of the scattered light intensity distribution acquired in the scattered light measurement information acquiring step and the scattered light intensity distribution calculation result calculated by calculation based on the object model match. Function parameter calculation processing step;
   A scattered light information processing method comprising:
2. The function to set the parameter in the function parameter setting step is the scattered light information reflected on the incident side of the measurement surface of the optical element and the outgoing side transmitted to the measured object with respect to the measured object model. The scattered light information processing method according to claim 1, which is a function representing scattered light information.
3. The information of the scattered light intensity distribution acquired in the scattered light measurement information acquiring step is at least a scattered light intensity distribution transmitted through the object to be measured or a scattered light intensity distribution reflected on the object to be measured,
   The measurement conditions of the scattered light intensity distribution input in the model generation step include at least the light intensity of the light incident on the object at the time of measuring the intensity distribution of the scattered light. Or the scattered light information processing method as described in 2.
4. The scattered light information acquiring step is characterized by acquiring at least a part of information of a scattered light intensity distribution transmitted through the object or a part of a scattered light intensity distribution reflected by the object. The scattered light measurement information processing method according to claim 3.
5. In the scattered light measurement information acquiring step, at least a scattered light intensity distribution transmitted through the object to be measured or a scattered light intensity distribution reflected from the object to be measured is normalized by the light intensity of incident light to the object to be measured The scattered light information processing method according to any one of claims 1 to 4, wherein a light intensity distribution is acquired.
6. The information of the scattered light intensity distribution acquired in the scattered light measurement information acquiring step is a scattered light intensity distribution of light transmitted through the object to be measured and a scattered light intensity distribution of light reflected on the object to be measured. The scattered light information processing method according to any one of claims 1 to 5.
7. The shape and optical properties of the object to be measured include at least a radius of curvature, an optical thickness, and a refractive index of the optical element as the object to be measured. The scattered light information processing method according to claim 1.
8. In the scattered light measurement information acquiring step, information of scattered light intensity distribution of light irradiated to the object to be measured at a plurality of different incident angles is acquired,
   The function parameter calculation processing step is a function parameter of each incident angle so that the information of the scattered light intensity distribution acquired in the scattered light measurement information acquiring step matches the scattered light intensity distribution calculation result calculated from the object model A provisional function parameter calculation step of calculating as a provisional function parameter;
   The information of the scattered light intensity distribution acquired in the scattered light measurement information acquiring step and the scattered light intensity distribution calculation result calculated using at least a part of the provisional function parameters of each incident angle with respect to the object model The scattered light information processing method according to claim 1 or 2, further comprising a function parameter determination step of adjusting a provisional function parameter so as to coincide with each other to determine a final function parameter.
9. A scattered light information processing apparatus for processing scattered light information of an object to be measured, comprising:
   The object to be measured is an optical element composed of a substance at least a part of which transmits light,
   A scattered light measurement information acquisition unit that acquires information of a scattered light intensity distribution of light irradiated to the object at a predetermined angle;
   A model generation unit that generates an object model from the shape and optical properties of the object to be measured and the measurement conditions of the scattered light intensity distribution;
   A function parameter setting unit configured to set a parameter of a function representing at least scattered light information on an output side transmitted through the object to the object model;
   A scattered light intensity distribution calculating unit that calculates a scattered light intensity distribution calculation result by calculation based on the object model;
   The function parameter is calculated such that the information of the scattered light intensity distribution acquired by the scattered light measurement information acquiring unit and the scattered light intensity distribution calculation result calculated by calculation based on the object model match. A function parameter calculation processing unit,
   A scattered light information processing apparatus characterized by having:
10. The function for setting the parameter in the function parameter setting unit is the scattered light information reflected on the incident side of the measurement surface of the optical element and the outgoing side transmitted through the object with respect to the object model. 10. The scattered light information processing apparatus according to claim 9, which is a function representing scattered light information.
11. The information of the scattered light intensity distribution acquired by the scattered light measurement information acquiring unit is at least a scattered light intensity distribution transmitted through the object to be measured or a scattered light intensity distribution reflected from the object to be measured,
    The measurement condition of the scattered light intensity distribution input in the model generation unit includes at least the light intensity of the light incident on the object at the time of the measurement of the scattered light intensity distribution. Or the scattered light information processing apparatus as described in 10.
12. The scattered light information acquisition unit is characterized by acquiring at least a part of information of a scattered light intensity distribution transmitted through the object or a part of a scattered light intensity distribution reflected by the object. The scattered light measurement information processing apparatus according to claim 11.
13. In the scattered light measurement information acquiring unit, at least a scattered light intensity distribution transmitted through the object to be measured or a scattered light intensity distribution reflected from the object to be measured is normalized by the light intensity of incident light to the object to be measured The scattered light information processing apparatus according to any one of claims 9 to 12, wherein a light intensity distribution is acquired.
14. The information of the scattered light intensity distribution acquired by the scattered light measurement information acquiring unit is a scattered light intensity distribution of light transmitted through the object to be measured and a scattered light intensity distribution of light reflected on the object to be measured. The scattered light information processing apparatus according to any one of claims 9 to 13.
15. The shape and optical properties of the object to be measured include at least a radius of curvature, an optical thickness, and a refractive index of the optical element as the object to be measured. The scattered light information processing apparatus according to claim 1.
16. The scattered light measurement information acquiring unit acquires information on the scattered light intensity distribution of the light irradiated to the object at a plurality of different incident angles,
    Furthermore, the function parameter of each incident angle is used as a provisional function parameter so that the information of the scattered light intensity distribution acquired by the scattered light measurement information acquiring unit matches the scattered light intensity distribution calculation result calculated from the object model A provisional function parameter calculation unit to calculate
    The information of the scattered light intensity distribution acquired by the scattered light measurement information acquisition unit and the scattered light intensity distribution calculation result calculated using at least a part of the provisional function parameters of each incident angle with respect to the object model 11. The scattered light information processing apparatus according to claim 9, further comprising a function parameter determination unit that adjusts a provisional function parameter so as to coincide with each other to determine a final function parameter.
17. A scattered light information processing system that measures scattered light of an object to be measured and processes scattered light information,
    The object to be measured is an optical element composed of a substance at least a part of which transmits light,
    A light irradiation unit that irradiates light at a predetermined angle with respect to the object to be measured;
    A scattered light measurement unit that receives at least light scattered by the object to be measured;
    A scattered light measurement information acquisition unit that acquires information of the scattered light intensity distribution of the object based on the information received by the scattered light measurement unit;
    An information storage unit for storing the shape and optical properties of the object to be measured and measurement conditions of the scattered light intensity distribution;
    A model generation unit that generates an object model from the stored shape, optical properties, and measurement conditions;
    A function parameter setting unit configured to set a parameter of a function representing at least scattered light information on an output side transmitted through the object to the object model;
    A scattered light intensity distribution calculation unit that calculates a scattered light intensity distribution calculation result by calculation from the object model;
    Function parameter for calculating the function parameter so that the information of the scattered light intensity distribution acquired by the scattered light measurement information acquiring unit and the scattered light intensity distribution calculation result calculated by the calculation from the object model match A calculation processing unit,
    A scattered light information processing system characterized by having.
18. The scattered light measurement unit includes a light receiving unit that receives light scattered and reflected by the object to be measured.
    The function for setting the parameter in the function parameter setting unit is the scattered light information reflected on the incident side of the measurement surface of the optical element and the outgoing side transmitted through the object with respect to the object model. 18. The scattered light information processing system according to claim 17, which is a function representing scattered light information.
19. The information of the scattered light intensity distribution acquired by the scattered light measurement information acquiring unit is at least a scattered light intensity distribution transmitted through the object to be measured or a scattered light intensity distribution reflected from the object to be measured,
    The measurement conditions of the scattered light intensity distribution input in the model generation unit include at least the light intensity of the light incident on the object at the time of the measurement of the scattered light intensity distribution. Or the scattered light information processing system as described in 18.
20. The scattered light information acquisition unit is characterized by acquiring at least a part of information of a scattered light intensity distribution transmitted through the object or a part of a scattered light intensity distribution reflected by the object. The scattered light measurement information processing system according to claim 19.
21. In the scattered light measurement information acquiring unit, at least a scattered light intensity distribution transmitted through the object to be measured or a scattered light intensity distribution reflected from the object to be measured is normalized by the light intensity of incident light to the object to be measured The scattered light information processing system according to any one of claims 17 to 20, which acquires a light intensity distribution.
22. The information of the scattered light intensity distribution acquired by the scattered light measurement information acquiring unit is a scattered light intensity distribution of light transmitted through the object to be measured and a scattered light intensity distribution of light reflected on the object to be measured. The scattered light information processing system according to any one of claims 17 to 21.
23. The shape and optical properties of the object to be measured include at least a radius of curvature, an optical thickness, and a refractive index of the optical element as the object to be measured. Scattered light information processing system described in.
24. The scattered light measurement information acquiring unit acquires information on the scattered light intensity distribution of the light irradiated to the object at a plurality of different incident angles,
    Furthermore, the function parameter of each incident angle is used as a provisional function parameter so that the information of the scattered light intensity distribution acquired by the scattered light measurement information acquiring unit matches the scattered light intensity distribution calculation result calculated from the object model A provisional function parameter calculation unit to calculate
    The information of the scattered light intensity distribution acquired by the scattered light measurement information acquisition unit and the scattered light intensity distribution calculation result calculated using at least a part of the provisional function parameters of each incident angle with respect to the object model The scattered light information processing system according to claim 17 or 18, further comprising a function parameter determination unit that adjusts a provisional function parameter so as to coincide with each other to determine a final function parameter.

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