Method for measurement, measurement system, and method for processing information

Abstract

To provide a method for easily and contactlessly generating information on the inclination of the surface of a target object.SOLUTION: The method for measurement includes: acquiring spectrum information of light from the surface of a target object; acquiring reference information including information of the optical reflection property of the surface of the target object; and generating information on the inclination of the surface of the target object on the basis of the reference information and the spectrum information.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to a measurement method, a measurement system, and an information processing method.

Background Art

[0002] In the measurement of optical properties such as the transmittance and reflectance of an object, the material, surface state, and surface inclination angle of the object greatly affect the measurement results. In particular, the surface inclination angle of the object easily changes depending on, for example, the measurement environment, the installation and fixing method of the object, and the skill of the measurer. For this reason, the surface inclination angle of the object tends to vary with each measurement attempt, and it is not uncommon for the measurement result of the inclination angle to be inaccurate.

[0003] In the conventional contact angle measurement using a level, when measuring the surface inclination angle of an object, the surface state of the object may deteriorate or the fixing state of the object may change. For this reason, non-contact angle measurement is required. Patent Documents 1 and 2 disclose examples of non-contact angle measurement.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present disclosure provides a measurement method capable of easily generating information on the inclination of the surface of an object in a non-contact manner, and a measurement system using the measurement method.

Means for Solving the Problems

[0006] A method according to one aspect of the present disclosure includes obtaining spectral information of light from the surface of an object, obtaining reference information including information on the light reflection characteristics of the surface of the object, and generating information regarding the inclination of the surface of the object based on the spectral information and the reference information.

[0007] The comprehensive or specific aspects of the present disclosure may be implemented in a recording medium such as a system, an apparatus, a method, an integrated circuit, a computer program, or a computer-readable recording disk, or may be implemented in any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. The computer-readable recording medium may include, for example, a non-volatile recording medium such as a CD-ROM (Compact Disc-Read Only Memory). The apparatus may be composed of one or more apparatuses. When the apparatus is composed of two or more apparatuses, the two or more apparatuses may be arranged in one device, or may be divided and arranged in two or more separate devices. In this specification and the claims, the "apparatus" may mean not only one apparatus but also a system composed of a plurality of apparatuses.

Advantages of the Invention

[0008] According to the technology of the present disclosure, it is possible to realize a measurement method capable of simply and non-contactingly generating information regarding the inclination of the surface of an object, and a measurement system using the measurement method.

Brief Description of the Drawings

[0009]

Fig. 1A

Fig. 1B

Fig. 2

Fig. 3A

Fig. 3B

Fig. 4A

Fig. 4B

Fig. 4C

Fig. 5A

Fig. 5B

Fig. 6

Fig. 7A

Fig. 7B

Fig. 8

Fig. 9

Fig. 10

Fig. 11

Fig. 12

Fig. 13

Fig. 14

Fig. 15

MODE FOR CARRYING OUT THE INVENTION

[0010] In the present disclosure, all or part of a circuit, unit, device, member or part, or all or part of a functional block in a block diagram can be executed by one or more electronic circuits including, for example, a semiconductor device, a semiconductor integrated circuit (IC), or an LSI (large scale integration). The LSI or IC may be integrated on one chip or may be configured by combining a plurality of chips. For example, functional blocks other than memory elements may be integrated on one chip. Here, although referred to as an LSI or IC, the name may change depending on the degree of integration, and it may be referred to as a system LSI, a VLSI (very large scale integration), or a ULSI (ultra large scale integration). A Field Programmable Gate Array (FPGA) programmed after manufacturing the LSI, or a reconfigurable logic device capable of reconfiguring the bonding relationship inside the LSI or setting up circuit sections inside the LSI can also be used for the same purpose.

[0011] Furthermore, all or part of the functions or operations of a circuit, unit, device, component, or part can be executed by software processing. In this case, the software is recorded on a non-transitory recording medium such as one or more ROMs, optical disks, hard disk drives, etc., and when the software is executed by a processor, the functions specified by the software are executed by the processor and peripheral devices. The system or device may include one or more non-transitory recording media on which the software is recorded, a processor, and the required hardware devices, such as an interface.

[0012] In the present disclosure, "light" means electromagnetic waves including not only visible light (wavelength of about 400 nm to about 700 nm), but also ultraviolet light (wavelength of about 10 nm to about 400 nm) and infrared light (wavelength of about 700 nm to about 1 mm).

[0013] Hereinafter, exemplary embodiments of the present disclosure will be described. Note that all of the embodiments described below show inclusive or specific examples. The numerical values, shapes, components, arrangement positions and connection forms of the components, steps, order of steps, etc. shown in the following embodiments are examples, and are not intended to limit the present disclosure. In addition, among the components in the following embodiments, the components not described in the independent claims indicating the most general concept are described as optional components. Also, each figure is a schematic diagram and is not necessarily drawn precisely. Furthermore, in each figure, substantially the same components are denoted by the same reference numerals, and duplicate explanations may be omitted or simplified.

[0014] Before describing embodiments of the present disclosure, with reference to FIGS. 1A and 1B, a mechanism will be described of how the tilt angle of the surface of an object and the angle of light incident on the object affect measurement. When an object is irradiated with light emitted from a light source, reflected light and scattered light are generated. Such reflected light and scattered light are detected by a light detection device. With the normal axis of the surface of the object as a reference axis, the fact that incident light is reflected at the same angle as the incident angle is generally called "specular reflection" or "regular reflection". In contrast, with the normal axis of the surface of the object as a reference axis, the fact that incident light is reflected at an angle different from the incident angle is called "diffuse reflection" or "irregular reflection". The specular reflection light generated by reflection of light on the surface of the object can contain a lot of information about the light source. In contrast, the diffuse reflection light generated by reflection of light on the surface of the object or in the vicinity thereof can contain a lot of information about the object, such as the light absorption rate and surface state of the material of the object.

[0015] FIG. 1A is a diagram schematically showing a state in which an object is irradiated with incident light having two different wavelengths λ1 and λ2 from each other, and specular reflection light and diffuse reflection light are generated. The thick arrowed lines shown in FIG. 1 represent incident light and specular reflection light, and the thin arrowed lines in black and dark gray shown in FIG. 1 represent diffuse reflection light of wavelengths λ1 and λ2, respectively. As shown in FIG. 1A, the spatial spread of the diffuse reflection light often varies depending on the wavelength. Therefore, as shown in the inset of FIG. 1A, the spectra of the diffuse reflection light received by the observers A and B at different positions are different from each other. The solid line and the broken line shown in the inset of FIG. 1A represent the spectra of the diffuse reflection light received by the observers A and B, respectively. In the spectrum of the diffuse reflection light received by the observer A, the light intensity of the wavelength λ1 is higher than the light intensity of the wavelength λ2. In contrast, in the spectrum of the diffuse reflection light received by the observer B, the light intensity of the wavelength λ2 is higher than the light intensity of the wavelength λ1.

[0016] As a prominent example where the spatial spread of diffusely reflected light differs between wavelengths λ1 and λ2, a hologram sheet can be cited. On the other hand, a standard white plate formed from barium sulfate is often designed such that the spatial spread of diffusely reflected light is uniform and does not depend on the wavelength. When the object 10 is not intentionally designed to be so, the spectrum of the diffusely reflected light often varies depending on the positions of observers A and B, as shown in the inset of FIG. 1A.

[0017] FIG. 1B is a diagram schematically showing a state in which an object is irradiated with light incident at two different angles to each other to generate diffusely reflected light. In the example shown in FIG. 1B, the light emitted from the light source 20a enters the object 10 at an angle closer to the normal of the surface 10s of the object 10 than the light emitted from the light source 20b. The thin lines with black and dark gray arrows shown in FIG. 1B represent the diffusely reflected light generated when the object 10 is irradiated with the light emitted from the light sources 20a and 20b, respectively. A standard white plate is often designed such that the spatial spread of diffusely reflected light is uniform and does not depend on the incident angle of the light. When the object 10 is not intentionally designed to be so, the spectrum of the diffusely reflected light received by the observer A changes according to the incident angle of the light.

[0018] The inventor has conceived a measurement method according to an embodiment of the present disclosure and a measurement system using the measurement method, which can easily and non-contact generate information regarding the inclination of the surface of an object by paying attention to the spectral change caused by the spatial spread of diffusely reflected light. The information regarding the inclination of the surface of the object is information indicating a quantity caused by the inclination of the surface of the object. Such information can be, for example, information indicating the inclination angle or the amount of deflection of the surface of the object. Hereinafter, the measurement method and the measurement system according to the embodiments of the present disclosure will be described.

[0019] The method according to the first aspect includes acquiring spectral information of light from the surface of an object, acquiring reference information including information on the light reflection characteristics of the surface of the object, and generating information regarding the inclination of the surface of the object based on the spectral information and the reference information.

[0020] By this method, information regarding the inclination of the surface of the object can be easily generated non-contact.

[0021] The method according to the second item is the method according to the first item, wherein the spectral information includes a plurality of light intensities respectively corresponding to a plurality of wavelength bands, and the reference information includes at least one of the incident angle of the light incident on the surface of the object and the exit angle of the light exiting from the surface of the object, and information indicating the relationship between the at least one angle and the plurality of light intensities respectively corresponding to the plurality of wavelength bands corresponding to the at least one angle.

[0022] By this method, the above-mentioned plurality of light intensities included in the spectral information and the above-mentioned plurality of light intensities included in the reference information can be compared to generate information regarding the inclination of the surface of the object.

[0023] The method according to the third item is the method according to the first or second item, wherein the information regarding the inclination of the surface of the object is information indicating the inclination angle of the surface of the object or information indicating the amount of deflection of the surface of the object.

[0024] By this method, information indicating the inclination angle or the amount of deflection of the surface of the object can be generated.

[0025] The method according to the fourth item is the method according to the third item, and includes determining whether the inclination angle or the amount of deflection is within an allowable range.

[0026] By this method, it can be determined whether the inclination angle or the amount of deflection is within an allowable range.

[0027] The method according to the fifth item is the method according to the fourth item, and further includes analyzing the surface of the object based on the spectral information when it is determined that the inclination angle or the amount of deflection is within the allowable range.

[0028] By this method, the surface of the object can be analyzed.

[0029] The method according to the sixth item further includes generating error information when it is determined that the inclination angle or the amount of deflection is not within the allowable range in the method according to the fourth item.

[0030] By this method, it is possible to notify the user that the inclination angle or the amount of deflection is not within the allowable range.

[0031] The method according to the seventh item further includes generating information for correcting the inclination angle when it is determined that the inclination angle is not within the allowable range in the method according to the fourth item.

[0032] By this method, the inclination angle can be kept within the allowable range.

[0033] The method according to the eighth item further includes determining whether the inclination angle or the amount of deflection can be estimated based on the spectral information and the reference information before generating information regarding the inclination of the surface of the object in the method according to any one of the third to seventh items.

[0034] By this method, it is possible to detect whether an abnormality has occurred on the surface of the object before generating information regarding the inclination of the surface of the object.

[0035] The method according to the ninth item is such that, in the method according to any one of the first to eighth items, the light from the surface of the object is light from one or more portions within the surface of the object. The method further includes displaying a GUI for the user to specify the one or more portions within the surface of the object.

[0036] By this method, the user can specify one or more portions within the surface of the object.

[0037] The method according to item 10 further includes generating the reference information before obtaining the reference information in the method according to any one of items 1 to 9. Generating the reference information includes repeatedly performing a first operation of changing at least one of an incident angle of light incident on the surface of the object and an exit angle of light exiting from the surface of the object, a second operation of causing a light source to emit light for irradiating the surface of the object, and a third operation of causing a light detection device to detect light from the surface of the object and generate spectral information of the light; and associating and storing at least one of the changed incident angle and exit angle and the spectral information obtained by repeatedly performing the first operation, the second operation, and the third operation.

[0038] By this method, reference information can be generated.

[0039] The method according to item 11 further includes irradiating the object with irradiation light including light corresponding to each of the plurality of wavelength bands in the method according to item 2. The light from the surface of the object is light caused by the irradiation light.

[0040] In this method, for example, the object is irradiated with irradiation light including first light corresponding to a first wavelength band and second light corresponding to a second wavelength band. In this case, spectral information can be obtained more efficiently as compared with a mode in which the first irradiation light corresponding to the first wavelength band and the second irradiation light corresponding to the second wavelength band are irradiated at different timings. Alternatively, spectral information can be obtained more efficiently as compared with a mode including a first light source that irradiates the first irradiation light and a second light source that irradiates the second irradiation light, respectively.

[0041] That is, by this method, spectral information for a plurality of wavelength bands can be obtained efficiently.

[0042] The system according to item 12 includes a light detection device that detects light from the surface of an object and generates spectral information of the light, and a processing circuit that acquires the spectral information from the light detection device, acquires reference information including information on the light reflection characteristics of the surface of the object, and generates information on the inclination of the surface of the object based on the spectral information and the reference information.

[0043] In this system, information on the inclination of the surface of an object can be easily generated non - contact.

[0044] The system according to item 13 further includes a storage device that stores the reference information in the system according to item 12. The processing circuit acquires the reference information from the storage device.

[0045] An information processing method executed by a computer according to item 14 includes acquiring first spectral information included in first light from a first region on the surface of an object, acquiring reference information including information on the light reflection characteristics of the surface of the object, determining whether the inclination of the surface of the object is within a predetermined range based on the first spectral information and the reference information, and when it is determined that the inclination is within the predetermined range, acquiring second spectral information included in second light from a second region on the surface, and determining the quality of the appearance related to the color of the object based on the second spectral information.

[0046] By this information processing method, an inspection of the appearance related to the color of an object can be performed.

[0047] The information processing method according to item 15 is the information processing method according to item 14, wherein the second region is wider than the first region.

[0048] By this information processing method, since the data amount of the first spectral information is smaller than the data amount of the second spectral information, the calculation load can be reduced in determining whether the inclination of the surface of the object is within a predetermined range.

[0049] The information processing method according to item 16 further includes generating correction information for correcting the inclination of the surface of the object when it is determined based on the first spectrum information and the reference information that the inclination of the surface of the object is not within a predetermined range in the information processing method according to item 14 or 15.

[0050] By this information processing method, the inclination of the surface of the object can be kept within a predetermined range.

[0051] The information processing method according to item 17 further includes determining whether an amount related to the inclination can be estimated based on the first spectrum information and the reference information, and determining whether the inclination is within the predetermined range when it is determined that the amount related to the inclination can be estimated, in the information processing method according to any one of items 14 to 16. The reference information includes range information indicating a range in which the light intensity corresponding to each of a plurality of wavelength bands can change according to the amount related to the inclination. Whether the amount related to the inclination can be estimated is determined based on the light intensity corresponding to each of the plurality of wavelength bands included in the first spectrum information and the range information.

[0052] By this information processing method, when the amount related to the inclination cannot be estimated, the processing operation can be aborted, and the simplification of the processing operation and the reduction of the processing load can be achieved.

[0053] In this system, the reference information can be acquired from the storage device.

[0054] (Embodiment 1) [Measurement System] First, with reference to FIG. 2, a configuration example of a measurement system according to Embodiment 1 of the present disclosure capable of generating information indicating the inclination angle of the surface of an object will be described. FIG. 2 is a block diagram schematically showing the configuration of the measurement system according to Exemplary Embodiment 1 of the present disclosure. The measurement system 100 shown in FIG. 2 includes a light detection device 30, a storage device 40, a display device 50, a processing circuit 60, and a memory 62. The dashed line shown in FIG. 2 represents the optical axis of the light detection device 30. The optical axis of the light detection device 30 can be, for example, the optical axis of a lens attached to the light detection device 30. The thin solid line with an arrow shown in FIG. 2 represents the input / output of signals.

[0055] In FIG. 2, in addition to the measurement system 100, a state in which the surface 10s of the object 10 is irradiated with light emitted from the light source 20 and diffused reflected light is generated is schematically shown. In the example shown in FIG. 2, the object 10 is fixed to the surface 12s of the sample stage 12, and the sample stage 12 is disposed on the rotary stage 14. By changing the orientation of the sample stage 12 by the rotary stage 14, the inclination angle of the surface 10s of the object 10 can be adjusted. The measurement system 100 may include the rotary stage 14 and / or the light source 20 as components.

[0056] The inclination angle of the surface 10s of the object 10 can be defined, for example, by the angle formed between a reference plane, which is a plane perpendicular to the optical axis of the light detection device 30, and the surface 10s of the object 10. The reference plane for the inclination angle may be another plane.

[0057] Note that the spatial spread of the diffused reflected light schematically shown in FIG. 2 is merely an example. The spatial spread of the diffused reflected light strongly depends on the physical properties and surface state of the object. Therefore, the degree, shape, and angular range of the spatial spread of the diffused reflected light are not limited to the example shown in FIG. 2. The same applies to the spatial spread of the diffused reflected light shown in the following figures.

[0058] As will be described in detail later, in the measurement system 100, the processing circuit 60 acquires spectral information of light from the surface 10s of the object 10 from the light detection device 30, and acquires reference information including information on the surface 10s of the object 10 from the storage device 40. The processing circuit 60 further generates information indicating the inclination angle of the surface 10s of the object 10 based on the spectral information and the reference information. As a result, the information can be generated simply and non-contact.

[0059] Each component of the object 10, the rotary stage 14, the light source 20, and the measurement system 100 will be described below.

[0060] <Object 10> The object 10 has a surface 10s that reflects light emitted from the light source 20. The surface 10s of the object 10 has the following light reflection characteristics. When the light emitted from the light source 20 is incident on the surface 10s of the object 10 at a certain angle, for example, in the vertical direction, the total reflectance of the specular reflection light and the diffuse reflection light generated when the surface 10s of the object 10 is irradiated with the light can be, for example, 1% or more, more desirably 10%. In the example shown in FIG. 2, the object 10 has a plate shape. The shape of the object 10 is not limited to the plate shape, and may be, for example, spherical. The surface 10s of the object 10 may be a flat surface or a curved surface.

[0061] In this specification, the light reflected by the surface 10s of the object 10 may be treated as including the light reflected by the surface 10s of the object 10 and the light scattered inside the vicinity of the surface of the object 10. Further, the light reflection characteristics of the surface 10s of the object 10 may be treated as characteristics including the light reflection characteristics of the surface 10s of the object 10 and the light scattering characteristics inside the vicinity of the surface of the object 10.

[0062] Alternatively, the object 10 may have a fluorescent medium. The fluorescent medium is excited by the light emitted from the light source 20. In that case, the light emitted from the fluorescent medium by the excitation may be detected as the light from the surface 10s of the object 10.

[0063] <Rotary stage 14> The rotary stage 14 can be, for example, a goniometer. The rotary stage 14 can adjust the rotation direction and / or the rotation angle. The rotary stage 14 may be rotated manually. When the rotary stage 14 is provided with an adjustment device for adjusting the rotation, the rotary stage 14 may be rotated by the adjustment device.

[0064] <Light source 20> The light source 20 includes a light-emitting element that emits light for irradiating the surface 10s of the object 10. The light may be, for example, white light, or may be ultraviolet light, visible light, or infrared light. The light can be, for example, parallel light. The light source 20 may include a plurality of light-emitting elements that respectively emit lights of a plurality of wavelengths such as red light, green light, and blue light. The light-emitting element can be, for example, an LED, a laser diode, an incandescent bulb, a halogen lamp, a xenon lamp, a mercury lamp, or the like.

[0065] The position and / or orientation of the light source 20 may be changed manually. When the light source 20 is provided with an adjustment device for adjusting the position and / or orientation, the position and / or orientation of the light source 20 may be changed by the adjustment device.

[0066] <Light detection device 30> The light detection device 30 detects light from the surface 10s of the object 10, generates spectral information of the light, and outputs a signal indicating the spectral information. The spectral information is information indicating a plurality of light intensities respectively corresponding to a plurality of wavelength bands included in the target wavelength range. When the light intensity is two-dimensionally distributed, the spectral information is information indicating a plurality of images respectively corresponding to a plurality of wavelength bands included in the target wavelength range.

[0067] Each wavelength band may have a wavelength width of, for example, several nm to several tens of nm. The wavelength widths of the plurality of wavelength bands may be uniform or non-uniform. Among the plurality of wavelength bands, there may or may not be a gap between two adjacent wavelength bands. The plurality of wavelength bands may be obtained by dividing the target wavelength range into a plurality of parts. The target wavelength range is an arbitrary wavelength range. The entire target wavelength range may be included in the wavelength range of visible light. Alternatively, among the target wavelength range, some wavelength ranges may be included in the wavelength range of visible light, and the remaining wavelength ranges may be included in the wavelength range of infrared or ultraviolet light.

[0068] The light detection device 30 may be, for example, a hyperspectral camera. As the light detection device 30, a hyperspectral camera including a spectroscope such as a prism and a grating may be used. By detecting the reflected light from a dot-like or line-like partial region of the surface 10s of the object 10 through the spectroscope, spectral information of the reflected light is generated on the surface 10s of the object 10. By repeating such light detection while moving the dot-like or line-like observation region on the surface 10s of the object 10, that is, while scanning, spectral information of light in the entire region of the surface 10s of the object 10 is generated.

[0069] Alternatively, as the light detection device 30, a hyperspectral camera using so-called compressive sensing technology may be used. By detecting the light from the surface 10s of the object 10 through a special filter array to generate a compressed image and restoring the compressed image, spectral information of the light from the surface 10s of the object 10 can be generated. Details of the hyperspectral camera using compressive sensing technology are disclosed in U.S. Patent No. 9,599,511. The entire disclosure content of U.S. Patent No. 9,599,511 is incorporated herein by reference.

[0070] The position and / or orientation of the light detection device 30 may be manually changed. When the light detection device 30 includes an adjustment device for adjusting the position and / or orientation, the position and / or orientation of the light detection device 30 may be changed by the adjustment device.

[0071] <Memory device 40> The memory device 40 stores reference information including information on the light reflection characteristics of the surface 10s of the object 10. Details of the reference information will be described later. The memory device 40 may receive the signal output from the light detection device 30 and store the spectral information of the light from the surface 10s of the object 10. The memory device 40 can be, for example, a hard disk drive (HDD) equipped with a magnetic disk or a solid state drive (SSD) equipped with a flash memory.

[0072] <Display device 50> The display device 50 displays an input user interface (UI) 50a and a display UI 50b. The input UI 50a is used for the user to input information. The information input by the user to the input UI 50a is received by the light detection device 30, the memory device 40, or the processing circuit 60. Details of the information input by the user will be described later. The display UI 50b is used to display the information generated by the processing circuit 60.

[0073] The input UI 50a and the display UI 50b are displayed as a graphical user interface (GUI). It can also be said that the information shown in the input UI 50a and the display UI 50b is displayed on the display device 50. The input UI 50a and the display UI 50b may be realized by a device capable of both input and output, such as a touch screen. In that case, the touch screen may function as the display device 50. When a keyboard and / or a mouse are used as the input UI 50a, the input UI 50a is a device independent of the display device 50.

[0074] <Processing circuit 60> The processing circuit 60 receives the signal from the light detection device 30 to acquire the spectral information of the light from the surface 10s of the object 10, and acquires reference information from an external storage device such as the storage device 40 or a server. When acquiring reference information from an external storage device, it is not necessary to provide the storage device 40. The processing circuit 60 further generates information indicating the inclination angle of the surface 10s of the object 10 based on the spectral information and the reference information.

[0075] The processing circuit 60 may control the rotation operation of the rotation stage 14 via an adjustment device. The processing circuit 60 may control the light emission operation of the light source 20, or may control the operation of changing the position and orientation of the light source 20 via an adjustment device. The processing circuit 60 may control the light detection operation of the light detection device 30, or may control the operation of changing the position and orientation of the light detection device 30 via an adjustment device. The processing circuit 60 may control the storage operation of the storage device 40. The processing circuit 60 may control the display operation of the display device 50.

[0076] Details of the measurement operation executed by the processing circuit 60 will be described later. The computer program executed by the processing circuit 60 is stored in a memory such as a ROM or a RAM (Random Access Memory). Thus, the measurement system 100 includes a processing device including the processing circuit 60 and the memory 62. The processing circuit 60 and the memory 62 may be integrated on one circuit board, or may be provided on separate circuit boards. The processing circuit 60 may be distributed among a plurality of circuits. The processing circuit 60, the memory 62, or the processing device may be installed at a remote location away from other components via a wired or wireless communication network.

[0077] [Reference Information and Its Generation Method] The reference information includes information indicating the relationship between at least one of the incident angle of light incident on the surface 10s of the object 10 and the exit angle of light exiting from the surface 10s of the object 10, and a plurality of light intensities respectively corresponding to a plurality of wavelength bands corresponding to the at least one angle. The incident angle can be defined, for example, by the angle formed between the normal to the surface 10s of the object 10 and the optical axis of the incident light. Similarly, the exit angle can be defined, for example, by the angle formed between the normal to the surface 10s of the object 10 and the optical axis of the exiting light. In this specification, the "light exiting from the surface 10s of the object 10" or "exiting light" means the light that travels along the optical axis of the light detection device 30 among the diffusely reflected light generated by irradiating the surface 10s of the object 10 with the light emitted from the light source 20.

[0078] When the incident angle or the exit angle is fixed, the reference information may not include information on the fixed incident angle or exit angle. In the example shown in FIG. 2, in the configuration where the arm attached to the sample stage 12 supports the light source 20, when the orientation of the sample stage 12 is changed by the rotary stage 14, the exit angle changes while the incident angle does not change. That is, the incident angle is fixed. On the other hand, in the configuration where the arm supports the light detection device 30, when the orientation of the sample stage 12 is changed by the rotary stage 14, the incident angle changes while the exit angle does not change. That is, the exit angle is fixed.

[0079] Referring to FIG. 3A, an example of the data of the reference information stored in the storage device 40 will be described. FIG. 3A is a diagram schematically showing an example of the data of the reference information stored in the storage device 40. In the example shown in FIG. 3A, the data of the reference information includes a plurality of tables. Each table shows the relationship between the incident angle, the exit angle, and the light intensity for a certain wavelength band. The wavelengths λ1, λ2, and λ3 shown in FIG. 3A represent the center wavelengths of the wavelength bands. In the data of the reference information shown in FIG. 3, the tables are divided by wavelength band, but they may also be divided by incident angle or exit angle.

[0080] The incident angle and the exit angle may be represented by an angle (°) as shown in FIG. 3A, or may be represented by any unit representing an angle such as a radian. The light intensity may be represented by a pixel value, or may be represented by a normalized numerical value including a percentage.

[0081] The reference information may further include information on the absorption rate and / or reflectance associated with the material of the object 10, or may include information on the surface state such as the roughness of the surface 10s. With such information, information indicating the inclination angle of the surface 10s of the object 10 can be generated more accurately. The information included in the reference information can be appropriately changed as needed.

[0082] Next, with reference to FIG. 3B, an example of a method for generating reference information will be described. FIG. 3B is a flowchart schematically showing an example of the operation in which the processing circuit 60 generates reference information. The processing circuit 60 executes the operations of steps S11 to S16 shown in FIG. 3B.

[0083] <Step S11> The user sets one or more incident angles and / or one or more exit angles via the input UI50a shown in FIG. 2. The processing circuit 60 acquires information on one or more incident angles and / or one or more exit angles from the input UI50a. The number of combinations of the incident angle and the exit angle is equal to the product of the number of incident angles and the number of exit angles. However, if a combination of a certain incident angle included in the set one or more incident angles and a certain exit angle included in the set one or more exit angles cannot be realized due to the configuration of the device, the combination is excluded. In that case, the number of combinations of the incident angle and the exit angle is smaller than the product of the number of incident angles and the number of exit angles. When the incident angle or the exit angle is fixed, the number of the incident angle or the exit angle is 1.

[0084] <Step S12> Based on the information of one or more incident angles and / or one or more exit angles, the processing circuit 60 changes the incident angle and / or the exit angle to one of the above combinations. Such a change in the incident angle and / or the exit angle can be realized by the processing circuit 60 rotating the rotation stage 14 via the adjustment device. In the configuration where the aforementioned arm supports the light source 20 or the light detection device 30, the incident angle or the exit angle is fixed. Alternatively, such a change in the incident angle and / or the exit angle can be realized by the processing circuit 60 changing the position and orientation of the light source 20 and / or the light detection device 30 via the adjustment device.

[0085] <Step S13> The processing circuit 60 causes the light source 20 to emit light for irradiating the surface 10s of the object 10.

[0086] <Step S14> The processing circuit 60 causes the light detection device 30 to detect the light from the surface 10s of the object 10 and generate the spectral information of the light.

[0087] <Step S15> The processing circuit 60 determines whether it has examined all combinations of the incident angle and the exit angle. If the determination is Yes, the processing circuit 60 executes the operation of Step S16. If the determination is No, the processing circuit 60 executes the operation of Step S12 again. In Step S12, the processing circuit 60 changes the incident angle and / or the exit angle to one of the combinations that have not been examined yet. In this way, the processing circuit 60 repeatedly executes the first operation of Step S12, the second operation of Step S13, and the third operation of Step S14.

[0088] <Step S16> The processing circuit 60 associates the changed incident angle and / or exit angle obtained by repeatedly executing the first operation, the second operation, and the third operation with the spectral information and stores them in the storage device 40.

[0089] The above operations of the processing circuit 60 can generate reference information.

[0090] [Method for estimating the inclination angle of the surface 10s of the object 10] Next, with reference to FIGS. 4A to 4C, a method for estimating the inclination angle of the surface 10s of the object 10 will be described. FIG. 4A is a diagram schematically showing a state in which a light detection device 30 detects diffused reflection light generated by irradiating the object 10 with irradiation light emitted from a light source 20. The irradiation light includes light of each of a plurality of wavelength bands. The diffused reflection light is light caused by the irradiation light. The object 10 is arranged in a state inclined by an angle θ from the aforementioned reference plane. The dotted line shown in FIG. 4A represents the reference plane. In the example shown in FIG. 4A, when the surface 10s of the object 10 changes by an angle θ from the reference plane, the incident angle and the exit angle change by θ.

[0091] FIG. 4B is a diagram schematically showing changes in the spectrum accompanying changes in the incident angle and the exit angle. In FIG. 4B, the light intensities at two certain wavelengths λ1 and λ2 are plotted as the spectrum. The broken line shown in FIG. 4B represents the spectra at a plurality of angles included in the reference information, and the solid line represents the actually measured spectrum. For simplicity, the incident angle and the exit angle are uniformly displayed by the value of the angle θ. In the example shown in FIG. 4B, the measured spectrum is located between the spectrum at θ = 5° and the spectrum at θ = 10° included in the reference information. The angle of the measured spectrum can be calculated, for example, by linearly interpolating the spectra at a plurality of angles included in the reference information. At that time, a method represented by the SAM (Spectral Angle Mapper) method may be used. In the SAM method, the spectrum is represented as a vector. The vector has a plurality of light intensities corresponding to a plurality of wavelength bands as components.

[0092] FIG. 4C is a diagram showing an example of reference information including spectra at a plurality of angles. In the example shown in FIG. 4C, the vector of the spectrum has the light intensities at wavelengths λ1 and λ2 as the first and second components, respectively. The vectors of the spectra at θ = 0°, 5°, and 10° included in the reference information are represented as (40, 85), (36, 70), and (30, 50), respectively. The vector of the measured spectrum is represented as (32, 58).

[0093] When calculating the inner product value between the normal vector (-85, 40) of the spectrum at θ = 0° and the vectors of the spectra at each angle, the inner product value becomes 0 at θ = 0°, -260 at θ = 5°, and -550 at θ = 10°. Assuming that the spectrum changes linearly between two adjacent angles among θ = 0°, 5°, and 10°, the inner product value f(θ) is represented by the following equations (1) and (2) using the angle θ.

Equation

Equation

[0094] The inner product value between the vector (32, 58) of the measured spectrum and the normal vector (-85, 40) of the spectrum at θ = 0° is -400. Since this inner product value is between -260 at θ = 5° and -550 at θ = 10°, applying equation (2), we get -58×θ + 30 = -400, which gives θ = 7.41°. Therefore, from the measured spectrum, it is estimated that the inclination angle of the surface 10s of the object 10 is θ = 7.41°. Note that this estimation method is an example. Of course, other estimation methods may be used.

[0095] Next, with reference to FIGS. 5A and 5B, another example of reference information including spectra at a plurality of angles will be described. FIG. 5A is a diagram schematically showing another example of reference information including spectra at a plurality of angles. The reference information shown in FIG. 5A shows the relationship between an angle and the spectrum at that angle. However, the spectrum at that angle is represented not by a plurality of light intensities respectively corresponding to a plurality of wavelength bands, but by a normalized inner product value between the vector of the spectrum at that angle and the vector of the spectrum at θ = 0°. The normalized inner product value is a value obtained by dividing the inner product value v1·v2 of the two spectral vectors v1 and v2 by the absolute values |v1| and |v2| of the two spectral vectors, that is, v1·v2 / (|v1||v2|). When the angle is θ = 0°, the normalized inner product value is 1. The inverse cosine of the normalized inner product value is called the "spectral angle". Instead of the normalized inner product value, the spectral angle may be used.

[0096] The reference information shown in FIG. 5A was generated as follows. A color sample having a surface exhibiting red was placed on the sample stage 12, and the rotation stage 14 was rotated to change the tilt angle of the surface of the color sample, and the spectrum of the light from the surface of the color sample was measured. The spectrum includes four light intensities respectively corresponding to four wavelengths of 475 nm, 505 nm, 605 nm, and 635 nm.

[0097] FIG. 5B is a diagram plotting the angles and normalized inner product values included in the reference information shown in FIG. 5A. The error bars shown in FIG. 5B represent the errors of the normalized inner product values based on the measurement errors of the spectra. In the example shown in FIG. 5B, when the tilt angle is ±6° or greater in the acquisition of the reference information, the change in the spectrum exceeds the measurement error, and it becomes possible to detect the tilt angle. The measurement error of the spectrum is caused by, for example, the intensity of illumination, the accuracy of the device used, and / or the signal-to-noise ratio. On the other hand, the change in the spectrum according to the tilt angle is caused by surface conditions such as, for example, the incident angle, the exit angle, the absorption rate and reflectivity of the material, and / or the surface roughness. The normalized inner product value also varies depending on which wavelength of light intensity is used as the spectrum. For the above reasons, in the measurement of the spectrum, in order to detect a smaller angle change, the incident angle and the exit angle, that is, the positions and orientations of the light source 20 and the light detection device 30, and the wavelength used for calculating the normalized inner product value can be appropriately selected.

[0098] In the example shown in FIG. 2, when the tilt angle of the surface 10s of the object 10 and the tilt angle of the surface 12s of the sample stage 12 correspond one-to-one, instead of the tilt angle of the surface 10s of the object 10, the tilt angle of the surface 12s of the sample stage 12 may be estimated by the above-described method. This is because the tilt angle of the surface 10s of the object 10 can be estimated based on the tilt angle of the surface 12s of the sample stage 12.

[0099] [Measurement Operation of Processing Circuit] Next, with reference to FIG. 6, an example of the measurement operation executed by the processing circuit 60 in Embodiment 1 will be described. The processing circuit 60 executes an operation of estimating the tilt angle of the surface 10s of the object 10. FIG. 6 is a flowchart schematically showing an example of the measurement operation executed by the processing circuit 60 in Embodiment 1. The processing circuit 60 executes the operations of steps S101 to S105 shown in FIG. 6.

[0100] <Step S101> The processing circuit 60 acquires reference information from the storage device 40. Regarding the acquisition of the reference information, the measurement system 100 may be configured as follows. That is, the user sets identification information for identifying the object 10 via the input UI 50a, and the processing circuit 60 receives a signal from the input UI 50a and acquires the reference information corresponding to the set identification information from the storage device 40. The identification information includes, for example, information specifying the name of the object and the surface state of the object.

[0101] <Step S102> The processing circuit 60 acquires spectral information of light from the surface 10s of the object 10 from the light detection device 30. The light detection device 30 generates the spectral information as follows.

[0102] The user sets light detection conditions via the input UI 50a. The light detection conditions can be, for example, at least one selected from the group consisting of exposure time, frame rate, digital gain, and gamma correction. After the user sets the light detection conditions, the user presses the start button for light detection displayed on the input UI 50a. The light detection device 30 receives a signal from the input UI 50a, detects light from the surface 10s of the object 10 based on the light detection conditions, generates spectral information of the light, and outputs a signal indicating the spectral information. Here, the spectral information is information indicating a plurality of images respectively corresponding to a plurality of wavelength bands.

[0103] <Step S103> The processing circuit 60 designates one part within the surface 10s of the object 10 as follows. The one part can be, for example, a point or a region having an extent. The processing circuit 60 causes the display UI50b to display an image of the object 10. The image of the object 10 can be one image selected from a plurality of images respectively corresponding to a plurality of wavelength bands, or an image obtained by superimposing two or more of the plurality of images. All of the plurality of images may be superimposed. The image of the object 10 may be displayed as a black-and-white image or may be displayed as a pseudo-colored RGB image. The user designates one part within the region corresponding to the surface 10s of the object 10 in the displayed image of the object 10 via the input UI50a. In this way, the processing circuit 60 displays a GUI for the user to designate one part within the surface 10s of the object 10. The processing circuit 60 receives a signal from the input UI50a and designates one part within the surface 10s of the object 10.

[0104] When detecting the reflected light from a partial region within the surface 10s of the object 10 using a hyperspectral camera including a spectroscope as the light detection device 30, the operation of step S103 may be omitted. Even when using a hyperspectral camera utilizing compressive sensing technology as the light detection device 30, if the spectral information of the light from the surface 10s of the object 10 does not depend on the position within the surface 10s of the object 10, the operation of step S103 may be omitted.

[0105] <Step S104> The processing circuit 60 obtains the spectral information of the light from the designated part by extraction from the spectral information acquired in step S102.

[0106] <Step S105> The processing circuit 60 estimates the tilt angle of the specified portion based on the spectral information and reference information of the light from the specified portion, and generates information indicating the tilt angle of the specified portion. The method for estimating the tilt angle is as described with reference to FIGS. 4A to 4C. The information indicating the tilt angle of the specified portion may be information indicating the tilt angle itself, or may be information from which the tilt angle can be derived. The processing circuit 60 may output the information indicating the tilt angle of the specified portion and display it on the display UI 50b, or may store it in the storage device 40.

[0107] Since the specified portion is a part of the surface 10s of the object 10, in this specification, the "specified portion" may be referred to as the "surface 10s of the object 10". For example, in this specification, the "light from the specified portion" is also referred to as the "light from the surface 10s of the object 10". Similarly, the tilt angle of the specified portion is also referred to as the "tilt angle of the surface 10s of the object 10".

[0108] By the above operation of the processing circuit 60, information indicating the tilt angle of the surface 10s of the object 10 can be generated.

[0109] Next, with reference to FIG. 7A, another example of the measurement operation executed by the processing circuit 60 in Embodiment 1 will be described. In addition to the operations of steps S101 to S105 shown in FIG. 6, the processing circuit 60 executes an operation of determining whether the estimated tilt angle is within an allowable range. FIG. 7A is a flowchart schematically showing another example of the measurement operation executed by the processing circuit 60 in Embodiment 1. The processing circuit 60 executes the operations of steps S101 to S108 and shown in FIG. 7A. The operations of steps S101 to S105 shown in FIG. 7A are the same as the operations of steps S101 to S105 shown in FIG. 6, respectively. The processing circuit 60 executes the operation of step S106 after step S105.

[0110] <Step S106> The processing circuit 60 determines whether the estimated tilt angle is within the allowable range. The allowable range of the tilt angle may be set by the user via the input UI50a, or may be automatically set based on reference information. In the example shown in FIG. 5B, when the tilt angle is less than 6 degrees, the spectral change becomes smaller than the measurement error, and it is not easy to determine whether the surface 10s of the object 10 is tilted. Therefore, the allowable range of the tilt angle can be set to an angle at which tilting can be detected, any value of 6 degrees or more in the example of FIG. 5B. If the determination is Yes, the processing circuit 60 executes the operation of step S107. If the determination is No, the processing circuit 60 executes the operation of step S108.

[0111] <Step S107> Based on the spectral information of the light from the surface 10s of the object 10, the processing circuit 60 analyzes the surface 10s of the object 10 and generates information obtained by analyzing the surface 10s of the object 10. Examples of the analysis include measurement of the freshness and / or sugar content of food, inspection of the appearance including the color of industrial products, measurement of the thickness of a transparent film, measurement of the surface moisture content of skin and wood, and inspection of water quality and / or soil. Before the analysis, the processing circuit 60 may cause the display UI50b to display that the estimated tilt angle is within the allowable range. A message such as "The tilt angle of the surface of the object is within the allowable range" may be displayed on the display UI50b. The processing circuit 60 may output the analyzed information and cause the display UI50b to display the information, or may store the information in the storage device 40.

[0112] <Step S108> The processing circuit 60 generates and outputs error information, and causes the display UI 50b to display the information. FIG. 7B is a diagram schematically showing an example of the error information displayed on the display UI 50b. In the example shown in FIG. 7B, as the error information, a message "Processing is aborted because the inclination angle of the surface of the object exceeds the allowable range" is displayed. Note that an image of the object is displayed in the upper left part of the background, the light detection conditions are displayed in the upper right part of the background, and a plurality of images corresponding to a plurality of wavelength bands are displayed in the lower part of the background. The processing circuit 60 may omit the operation of step S108 and end the measurement operation.

[0113] Next, with reference to FIG. 8, still another example of the measurement operation executed by the processing circuit 60 in Embodiment 1 will be described. In addition to the operations of steps S101 to S108 shown in FIG. 7A, the processing circuit 60 executes an operation for correcting the inclination angle of the surface 10s of the object 10. FIG. 8 is a flowchart schematically showing still another example of the measurement operation executed by the processing circuit 60 in Embodiment 1. The processing circuit 60 executes the operations of steps S101 to S109 shown in FIG. 8. The operations of steps S101 to S108 shown in FIG. 8 are the same as the operations of steps S101 to S108 shown in FIG. 7A, respectively. The processing circuit 60 executes the operation of step S109 after step S108. Note that the processing circuit 60 may omit the operation of step S108 and execute the operation of step S109 after step S106.

[0114] <Step S109> The processing circuit 60 generates correction information for correcting the inclination angle of the surface 10s of the object 10. The correction information may include, for example, the rotation direction and / or rotation angle of the rotary stage 14 for bringing the estimated inclination angle within the allowable range. The processing circuit 60 may cause the display UI 50b to display the correction information. The user manually corrects the rotation direction and / or rotation angle of the rotary stage 14 based on the displayed correction information. Alternatively, the processing circuit 60 may correct the rotation direction and / or rotation angle of the rotary stage 14 via an adjustment device.

[0115] After step S109, the processing circuit 60 re-executes the operations of steps S104 to S106. If the determination is No even after the operation of step S106 is executed a predetermined number of times, the processing circuit 60 may end the measurement operation after executing the operation of step S108, or may end the measurement operation without executing the operation of step S108. The predetermined number of times may be, for example, once, twice, or three or more times. Note that when the predetermined number of times is once and the processing circuit 60 ends the measurement operation after executing the operation of step S108, the flowchart shown in FIG. 8 becomes the same as the flowchart shown in FIG. 7A.

[0116] From the above, according to Embodiment 1, it is possible to realize a measurement method that can easily generate information indicating the inclination angle of the surface 10s of the object 10 in a non-contact manner, and a measurement system 100 using the measurement method. The measurement method according to Embodiment 1 is simple in that information indicating the inclination angle of the surface 10s of the object 10 can be generated by detecting the light from the surface 10s of the object 10 once with a single light detection device 30.

[0117] In the measurement method disclosed in Patent Document 1, since imaging is performed multiple times, the time efficiency is low. In the measurement method disclosed in Patent Document 2, since a plurality of devices are used, the device becomes large. On the other hand, in the measurement method according to Embodiment 1, since the number of light detections is once, the time efficiency is excellent, and since a single light detection device 30 is used, the measurement system 100 can be miniaturized. The measurement method according to Embodiment 1 enables simplification of the processing operation, as well as simplification and miniaturization of the measurement system 100.

[0118] In the measurement method according to Embodiment 1, the reference information, the spectral information of the light from the surface 10s of the object 10, and the information indicating the inclination angle of the surface 10s of the object 10 are generated by the measurement system 100. The reference information may be generated by a first device including the light detection device 30, the storage device, the input UI 50a, and the processing circuit 60. The spectral information of the light from the surface 10s of the object 10 may be generated by a second device including the light detection device 30 and the input UI 50a. The information regarding the inclination of the surface 10s of the object 10 may be generated by a third device including the processing circuit 60. The first device, the second device, and the third device are independent devices from each other.

[0119] (Embodiment 2) Next, with reference to FIG. 9, a measurement method according to Embodiment 2 of the present disclosure capable of generating information indicating the amount of deflection of the surface 10s of the object 10 will be described. FIG. 9 is a diagram for explaining the measurement method according to Embodiment 2 of the present disclosure. In the example shown in FIG. 9, the surface 10s of the object 10 is irradiated with incident light, and diffuse reflected light is generated at a plurality of portions A to C on the surface 10s of the object 10. For simplicity, the traveling directions of the light incident on the plurality of portions A to C are all the same, the light detection device 30 is sufficiently separated from the surface 10s of the object 10, and it is assumed that the difference in the emission angles depending on the positions of the plurality of portions A to C on the surface 10s of the object 10 can be ignored. The two wavy lines shown in FIG. 9 represent omitting a part of the region between the object 10 and the light detection device 30.

[0120] As the light detection device 30, a hyperspectral camera including a spectroscope or a hyperspectral camera using compressive sensing technology may be used. Alternatively, the light detection device 30 may include a plurality of spectroscopic elements arranged one-dimensionally or two-dimensionally. Each of the plurality of spectroscopic elements detects the light from a corresponding one of the portions and generates the spectral information of the light. The solid double-headed arrow shown in FIG. 9 represents the light detection region of the light detection device 30. The plurality of portions A to C are located within the light detection region.

[0121] In the example shown in FIG. 9, the inclination angles of portions A and C are zero, and portions A and C are not inclined from the plane perpendicular to the optical axis of the light detection device 30. In contrast, the inclination angle of portion B located between portions A and C is non-zero, and portion B is slightly inclined from the plane perpendicular to the optical axis of the light detection device 30. The spectral information of the light from portion B that is slightly inclined is different from the spectral information of the light from portions A and C that are not inclined. By associating the spatial information indicating the positions of portions A to C with the spectral information of the light from portions A to C, it is possible to generate information indicating the change in the local inclination angle of the surface 10s of the object 10, that is, the amount of deflection.

[0122] Next, with reference to FIG. 10, an example of the measurement operation executed by the processing circuit 60 in Embodiment 2 will be described. The processing circuit 60 executes an operation of estimating the amount of deflection of the surface 10s of the object 10. FIG. 10 is a flowchart schematically showing an example of the measurement operation executed by the processing circuit 60 in Embodiment 2. The processing circuit 60 executes the operations of steps S101, S102, S107, and S110 to S115 shown in FIG. 10. The operations of steps S101, S102, and S107 shown in FIG. 10 are the same as the operations of steps S101, S102, and S107 shown in FIG. 7A, respectively. The processing circuit 60 executes the operation of step S110 after step S102.

[0123] <Step S110> The processing circuit 60 designates a plurality of portions within the surface 10s of the object 10 as follows. The processing circuit 60 causes the display UI50b to display the image of the object 10 described above. The user designates a plurality of portions within the region corresponding to the surface 10s of the object 10 in the displayed image via the input UI50a. The plurality of portions are located apart from each other. In this way, the processing circuit 60 displays a GUI for the user to designate a plurality of portions within the surface 10s of the object 10. The processing circuit 60 receives a signal from the input UI50a and designates a plurality of portions within the surface 10s of the object 10. Note that the plurality of portions may be manually designated by the user as described above, or may be automatically designated. When the plurality of portions are automatically designated, they may be designated so that the intervals between the plurality of portions are constant, or features may be detected from the image of the object 10 and the plurality of portions may be designated so that many of the plurality of portions exist in the features. Designation of the plurality of portions in the features is useful, for example, for inspecting products or foods conveyed by a belt conveyor.

[0124] <Step S111> The processing circuit 60 acquires spectral information of light from the designated plurality of portions by extraction from the spectral information acquired in step S102.

[0125] <Step S112> The processing circuit 60 estimates the inclination angles of the designated plurality of portions based on the spectral information of light from the designated plurality of portions and the reference information, and generates information indicating the inclination angles of the designated plurality of portions.

[0126] Since the designated plurality of portions are part of the surface 10s of the object 10, in this specification, the "designated plurality of portions" may be rephrased as the "surface 10s of the object 10". For example, in this specification, the "light from the designated plurality of portions" is also referred to as the "light from the surface 10s of the object 10". Similarly, the inclination angle of the designated plurality of portions is also referred to as the "inclination angle of the surface 10s of the object 10".

[0127] <Step S113> The processing circuit 60 estimates the amount of deflection of the surface 10s of the object 10 by associating the spatial information indicating the positions of a plurality of portions with the information indicating the inclination angles of the plurality of portions, and generates information indicating the amount of deflection of the surface 10s of the object 10. The information indicating the amount of deflection of the surface 10s of the object 10 may be information indicating the amount of deflection itself, or may be information from which the amount of deflection can be derived. The information indicating the amount of deflection of the surface 10s of the object 10 may be information representing the estimated amount of deflection in the form of a heat map or contour lines.

[0128] <Step S114> The processing circuit 60 determines whether or not the estimated amount of deflection is within an allowable range. In other words, the processing circuit 60 determines whether or not the inclination angles of all of the plurality of portions are within the allowable range described in step S106 shown in FIG. 7A. The allowable range of the amount of deflection may be set by the user via the input UI50a, or may be automatically set based on reference information. If the determination is Yes, the processing circuit 60 executes the operation of step S107. If the determination is No, the processing circuit 60 executes the operation of step S115.

[0129] <Step S115> The processing circuit 60 generates and outputs error information, and causes the display UI50b to display the information. As the error information, for example, a message such as "The amount of deflection of the surface of the object exceeds the allowable range" may be displayed on the display UI50b. Note that the processing circuit 60 may omit the operation of step S115 and end the measurement operation.

[0130] In the above operation, after executing the operation of step S113, the processing circuit 60 may omit the operations after step S114 and end the measurement operation.

[0131] From the above, according to Embodiment 2, it is possible to realize a measurement method that can simply and non - contactingly generate information indicating the amount of deflection of the surface 10s of the object 10, and a measurement system 100 using the measurement method. Similar to the measurement method according to Embodiment 1, the measurement method according to Embodiment 2 enables simplification of the processing operation and simplification and miniaturization of the measurement system 100.

[0132] Note that in the measurement method according to Embodiment 2, similar to the measurement method according to Embodiment 1, reference information may be generated by the first device, spectral information of light from the surface 10s of the object 10 may be generated by the second device, and information indicating the amount of deflection of the surface 10s of the object 10 may be generated by the third device.

[0133] (Embodiment 3) Next, with reference to FIG. 11, a measurement method according to Embodiment 2 of the present disclosure that can detect whether an abnormality has occurred on the surface 10s of the object 10 will be described. Due to reasons such as foreign matter adhesion and painting defects, an abnormality may occur on the surface 10s of the object 10. Even if the inclination angle or the amount of deflection of the surface 10s of the object 10 with an abnormality is estimated, the estimated inclination angle or amount of deflection is inaccurate. Therefore, if it can be detected that an abnormality has occurred on the surface 10s of the object 10, the operation of estimating the inclination angle or the amount of deflection of the surface 10s of the object 10 can be aborted, enabling simplification of the processing operation and reduction of the processing load.

[0134] FIG. 11 is a diagram for explaining the measurement method according to Embodiment 3 of the present disclosure. In FIG. 11, for simplicity, a spectrum having light intensities at wavelengths λ1 and λ2 is shown on a two - dimensional plane. In the two - dimensional plane, the horizontal axis and the vertical axis represent the light intensities at wavelengths λ1 and λ2, respectively. A spectrum having N light intensities corresponding to N wavelengths can be shown in an N - dimensional space. N is a natural number of 2 or more.

[0135] Here, the reference signs include spectral information at a plurality of inclination angles θ = 0°, θ = ±6°, and θ = ±12° of the surface 10s of the object 10. In the example shown in FIG. 11, the spectra at the plurality of inclination angles θ = 0°, θ = ±6°, and θ = ±12° included in the reference information are plotted. The white dotted circles represent the spectra included in the reference information. When the angle is changed from θ = 12° to θ = -12°, the spectra included in the reference information draw the locus shown in FIG. 11. In this specification, the locus means "a set of points satisfying the same conditions". In the example shown in FIG. 11, the same conditions refer to the relationship between the inclination angle and the spectrum. Mathematically, the locus is a line segment represented by an equation, but in reality, since measurement errors occur, the locus of the spectrum has a width and is represented as a region in space. For this reason, the locus shown in FIG. 11 has an elongated elliptical shape in the two-dimensional plane. The hatched region shown in FIG. 11 represents the locus of the spectra included in the reference information.

[0136] When there is no abnormality on the surface 10s of the object 10, the measured spectrum should be located on the locus of the spectra included in the reference information regardless of the inclination angle of the surface 10s of the object 10. In other words, as shown in FIG. 11, if the measured spectrum is not located on the locus, it can be seen that an abnormality has occurred on the surface 10s of the object 10. The solid circles shown in FIG. 11 represent the measured spectra.

[0137] Hereinafter, a method for generating the locus of the spectra shown in FIG. 11 will be described in more detail. The locus of the spectra can be generated, for example, by the following operations (a) to (d) by the processing circuit 60. (a) Acquire reference information from the storage device 40. (b) Select N wavelength bands included in the reference information. (c) For each of the N wavelength bands included in the reference information, plot the corresponding data points on an N-dimensional space. (d) Assign the width of the measurement error included in the reference information to the data points.

[0138] (b)'s operation may be executed based on the information input by the user. For example, when estimating the tilt angle using the information of N wavelength bands out of the information of a plurality of wavelength bands that can be acquired by the light detection device 30, the processing circuit 60 may display a GUI for the user to specify the N wavelength bands. The processing circuit 60 selects the N wavelength bands specified by the user.

[0139] The processing circuit 60 may execute the operation of (b) before the operation of (a). In that case, in the operation of (a), the processing circuit 60 acquires the reference information about the N wavelength bands selected by the operation of (b), while it may not be necessary to acquire the reference information about the remaining wavelength bands not selected by the operation of (b).

[0140] When executing the operation of (b), the processing circuit 60 may not be limited to the operation of selecting the information of the wavelength band specified by the user, but may also execute the operation of selecting a specified wavelength band. For example, the processing circuit 60 can generate information regarding the tilt using the information of a number of wavelength bands less than the information of a plurality of wavelength bands that can be acquired by the light detection device 30. As a result, the amount of calculation for generating the information regarding the tilt can be reduced, and the load in information processing can be reduced. Note that when the number of a plurality of wavelength bands that can be acquired by the light detection device 30 is N, and the number of wavelength bands used for estimating the tilt angle is also N, the operation of (b) can be omitted.

[0141] In the operation of (c), for each of the N wavelength bands selected by the operation of (b), the processing circuit 60 acquires the corresponding data points from the reference information and plots the data points on an N-dimensional space. FIG. 12 schematically shows an example of the spectrum locus when the wavelength bands 1 and 2 are selected with N = 2 in the operation of (b). The wavelength bands 1 and 2 have different wavelength ranges from each other. The wavelength band 1 has, for example, a wavelength range of 450 nm or more and 470 nm or less, and the wavelength band 2 may have, for example, a wavelength range of 630 nm or more and 640 nm or less. Thus, the width of the wavelength range may be different for each selected wavelength band. The wavelength ranges of the wavelength bands may be discontinuous.

[0142] An example of the reference information for the wavelength bands 1 and 2 is shown in Table 1. The following θ represents the tilt angle as in the example shown in FIG. 11. For Table 1, the numbers representing the light intensity in each wavelength band may be, for example, pixel values output from each pixel included in the image sensor, or may be normalized numerical values including percentages.

[0143]

Table 1

[0144] When the reference information shown in Table 1 is used, the horizontal axis shown in FIG. 12 represents the light intensity in the wavelength band 1, and the vertical axis shown in FIG. 12 represents the light intensity in the wavelength band 2. The processing circuit 60 plots the data points in Table 1 on a two-dimensional space. The processing circuit 60 plots, for example, (24, 32) on the two-dimensional space as the data point with θ = -12°, and plots (35, 41) on the two-dimensional space as the data point with θ = -6°. Similarly, the processing circuit 60 plots the data points of the wavelength bands 1 and 2 on the two-dimensional space for other θ values included in the reference information.

[0145] In the operation of (d), the processing circuit 60 assigns the width of the measurement error included in the reference information to the data points. The measurement error can be derived in the operation of generating the reference information shown in FIG. 3B. Theoretically, the linear locus connecting the plotted data points represents the locus of the spectrum included in the reference information. However, since a finite error occurs when actually measuring the light intensity corresponding to each of a plurality of wavelength bands, the locus of the spectrum becomes a region having the width of the measurement error.

[0146] As shown in Table 1, when θ = -12°, the measurement error of the light intensity in wavelength band 1 is 5, and the measurement error of the light intensity in wavelength band 2 is also 5. Therefore, when θ = -12°, the processing circuit 60 assigns, as the measurement error, a width of 5 in the horizontal axis direction and 5 in the vertical axis direction to the data points of (24, 32). When θ = -6°, the measurement error of the light intensity in wavelength band 1 is 6, and the measurement error of the light intensity in wavelength band 2 is 7. Therefore, when θ = -6°, the processing circuit 60 assigns, as the measurement error, a width of 6 in the horizontal axis direction and 7 in the vertical axis direction to the data points of (35, 41). Similarly, the processing circuit 60 assigns the width of the measurement error of the light intensity in each of wavelength band 1 and wavelength band 2 to the other data points of θ included in the reference information.

[0147] In this way, the processing circuit 60 can show a region having the width of the measurement error on the two-dimensional space. The gray region shown in FIG. 12 represents the region having the width of the measurement error. The gray region is the locus of the spectrum included in the reference information taking into account the measurement error, and is shown more specifically compared to the hatched region shown in FIG. 11. It can be said that the locus of the spectrum included in the reference information is information indicating the range of the light intensity that can change according to the change of the inclination angle of the object 10 and the quantity related to the angle such as the amount of deflection.

[0148] Next, referring to FIG. 13, an example of the measurement operation executed by the processing circuit 60 in Embodiment 3 will be described. In addition to the operations of steps S101 to S109 shown in FIG. 8, the processing circuit 60 executes an operation of determining whether the inclination angle of the surface 10s of the object 10 can be estimated. FIG. 13 is a flowchart schematically showing an example of the measurement operation executed by the processing circuit 60 in Embodiment 3. The processing circuit 60 executes the operations of steps S101 to S109, S116, and S117 shown in FIG. 13. The operations of steps S101 to S109 shown in FIG. 13 are the same as the operations of steps S101 to S109 shown in FIG. 8, respectively. The processing circuit 60 executes the operation of step S116 after step S104.

[0149] <Step S116> Based on the spectral information and reference information of the light from the specified part, the processing circuit 60 determines whether the inclination angle of the specified part can be estimated. Specifically, the processing circuit 60 determines whether the spectrum of the light from the specified part is located on the trajectory of the spectrum included in the reference information. If the determination is Yes, the processing circuit 60 executes the operation of step S105. If the determination is No, the processing circuit 60 executes the operation of step S117.

[0150] <Step S117> The processing circuit 60 generates and outputs error information, and causes the display UI50b to display the information. As the error information, for example, a message such as "An abnormality has occurred on the surface of the object" may be displayed on the display UI50b. Further, among the images of the object 10, the specified part may be highlighted as the part where the abnormality has occurred and displayed on the display UI50b. Note that the processing circuit 60 may omit the operation of step S117 and end the measurement operation.

[0151] Next, with reference to FIG. 14, another example of the measurement operation executed by the processing circuit 60 in Embodiment 3 will be described. In addition to the operations of steps S101, S102, S107, S110 to S115 shown in FIG. 10, the processing circuit 60 may execute an operation of determining whether it is possible to estimate the amount of deflection of the surface 10s of the object 10. FIG. 14 is a flowchart schematically showing another example of the measurement operation executed by the processing circuit 60 in Embodiment 3. The processing circuit 60 executes the operations of steps S101, S102, S107, S110 to S115, S117, and S118 shown in FIG. 14. The operations of steps S101, S102, S107, S110 to S115 shown in FIG. 14 are the same as the operations of steps S101, S102, S107, S110 to S115 shown in FIG. 10, respectively. The operation of step SS117 shown in FIG. 14 is the same as the operation of step S117 shown in FIG. 13. The processing circuit 60 executes the operation of step S118 after step S111.

[0152] <Step S118> The processing circuit 60 determines whether it is possible to estimate the tilt angles of the specified plurality of portions based on the spectral information and the reference information of the light from the specified plurality of portions. Specifically, the processing circuit 60 determines whether the spectra of the light from the specified plurality of portions are located on the locus of the spectra included in the reference information. If the determination is Yes, the processing circuit 60 executes the operation of step S112. If the determination is No, the processing circuit 60 executes the operation of step S117.

[0153] Next, with reference to FIG. 15, still another example of the measurement operation executed by the processing circuit 60 in Embodiment 3 will be described. FIG. 15 is a flowchart schematically showing still another example of the measurement operation executed by the processing circuit 60 in Embodiment 3. In this example, as an analysis of the surface 10s of the object 10, the processing circuit 60 performs an analysis related to the inspection of the appearance including the color tone of the industrial product.

[0154] In Embodiment 3, the processing circuit 60 executes the operation of step S119 instead of the operation of step S103 shown in FIG. 13, and executes the operation of step S120 instead of the operation of step S104. The processing circuit 60 executes the operation of step S121 instead of the operation of step S116 shown in FIG. 13, and executes the operation of step S122 instead of the operation of step S105. After the operation of step S106 shown in FIG. 13, the processing circuit 60 executes the operation of step S123, and executes the operation of step S124 instead of the operation of step S107.

[0155] <Step S119> As described in step S103, the processing circuit 60 designates one part within the surface 10s of the object 10. This one part is herein referred to as the "first region". The second region to be described later is a region wider than the first region.

[0156] <Step S120> The processing circuit 60 acquires the spectral information of the first region. The spectral information of the first region means the spectral information included in the first light from the first region, and is also referred to as "first spectral information" in this specification.

[0157] <Step S121> The processing circuit 60 determines whether the inclination angle of the first region can be estimated based on the spectral information of the first region. The method for determining whether the inclination angle can be estimated is as described in step S116.

[0158] <Step S122> The processing circuit 60 estimates the inclination angle based on the spectral information of the first region and the reference information, and generates information indicating the inclination angle of the designated part. The method for estimating the inclination angle is as described in step S105.

[0159] <Step S123> The processing circuit 60 acquires spectral information of a second region within the surface 10s of the object 10. The spectral information of the second region means the spectral information included in the second light from the second region, and is also referred to as "second spectral information" in this specification.

[0160] The second region is a region wider than the first region. The second region can be, for example, a region including the first region. That is, a part of the second region can overlap the entire first region. Alternatively, the second region may be a region that does not include the first region. That is, the second region does not have to overlap the first region. The second region corresponds to, for example, the analysis target range in step S124 described later.

[0161] The processing circuit 60 may display a GUI for the user to specify one region within the surface 10s of the object 10, and specify the second region by receiving a signal from the input UI50a. The processing circuit 60 may determine the following plurality of pixels as the plurality of pixels within the second region. The plurality of pixels includes one or more pixels within the first region included in the image of the object 10 and a predetermined number of pixels located around them.

[0162] The image of the object 10 can be one image selected from a plurality of images respectively corresponding to a plurality of wavelength bands, an image in which two or more of the plurality of images are superimposed, or a compressed image. The processing circuit 60 may extract the contour of the object 10 by detecting the edge of the image of the object 10, and determine the plurality of pixels included inside the extracted contour as the plurality of pixels within the second region. Edge detection can be performed by known processing methods such as Sobel filter, Laplacian filter, and Canny filter.

[0163] <Step S124> The processing circuit 60 performs an analysis related to the inspection of the appearance including the color tone of the industrial product based on the spectral information of the second region. The analysis can be performed, for example, by regression analysis, multivariate analysis, or the SAM method described above.

[0164] The processing circuit 60 may perform analysis based on the average spectrum obtained from the spectrum information of the second region. For example, for an image corresponding to the i-th (where i is a natural number from 1 to N) wavelength band among a plurality of wavelength bands, the processing circuit 60 may perform analysis based on the average pixel values of a plurality of pixels within the second region included in the image. Alternatively, for each of a plurality of images respectively corresponding to a plurality of wavelength bands, the processing circuit 60 may calculate the average pixel values of a plurality of pixels within the second region included in each image, and perform analysis based on the plurality of average pixel values thus obtained.

[0165] When performing analysis related to the inspection of the appearance including the color tone of industrial products, the storage device 40 may store model data used for the determination of the appearance inspection. The model data may be, for example, data indicating the spectrum information of products determined to be non-defective in the appearance inspection. The analysis by the processing circuit 60 may include, for example, comparing the plurality of average pixel values described above with a plurality of model data respectively corresponding to the plurality of wavelength bands. In this way, the processing circuit 60 may perform an inspection of the appearance including the color tone of industrial products based on the comparison between the spectrum information of the second region and the model data.

[0166] As another embodiment, the second region may be divided into a plurality of sub-regions. The plurality of sub-regions includes a first sub-region and a second sub-region that are different from each other. The processing circuit 60 may perform an inspection to determine the uniformity of the color tone of the second region of the object 10 based on the spectrum information of the first sub-region and the spectrum information of the second sub-region within the second region. In this case, the processing circuit 60 examines the similarity between the spectrum information of the first sub-region and the spectrum information of the second sub-region. The processing circuit 60 may determine that the object 10 is a non-defective product when the similarity is high, and may determine that the object 10 is a defective product when the similarity is low.

[0167] The information indicating the determination result of the appearance inspection may be information indicating pass or fail as described above, or may be information using a certain scale representing quality. Further, in the image showing the object 10, the determination result may be shown by emphasizing the portion where the inspection result is determined to be defective.

[0168] As described above with reference to FIG. 15, the processing circuit 60 determines whether the tilt angle can be estimated and whether the tilt angle is within an allowable range based on the spectral information of the first region that is narrower than the second region. The processing circuit 60 further performs an analysis based on the spectral information of the second region that is wider than the first region.

[0169] Since the first region is narrower than the second region, the data amount of the spectral information of the first region is smaller than the data amount of the spectral information of the second region. Therefore, compared with the case of determining whether the tilt angle can be estimated and whether the tilt angle is within an allowable range based on the spectral information of the second region and performing an analysis, the computational load on the processing circuit 60 can be reduced. Further, since the analysis is performed after confirming that the tilt angle is within the allowable range, the analysis accuracy can be improved.

[0170] Note that in the above example, it has been described assuming that the second region is wider than the first region, but the first region and the second region may have the same width. Alternatively, the first region may be wider than the second region.

[0171] The spectral information of the first region and the spectral information of the second region may be acquired by one light detection operation by the light detection device 30. For example, by one imaging operation using a hyperspectral camera, a plurality of images respectively corresponding to a plurality of wavelength bands may be acquired, and the spectral information of the first region and the spectral information of the second region may be acquired from the plurality of images.

[0172] Alternatively, the spectral information of the first region and the spectral information of the second region may be acquired by two light detection operations by the light detection device 30. For example, by a first imaging operation using a hyperspectral camera, a plurality of images respectively corresponding to a plurality of wavelength bands may be acquired, and the spectral information of the first region may be acquired from the plurality of images. Next, by a second imaging operation using a hyperspectral camera, a plurality of images respectively corresponding to a plurality of wavelength bands may be acquired, and the spectral information of the second region may be acquired from the plurality of images.

[0173] From the above, according to Embodiment 3, it is possible to realize a measurement method capable of detecting whether or not an abnormality has occurred on the surface 10s of the object 10, and a measurement system 100 using the measurement method.

Industrial Applicability

[0174] The technology of the present disclosure can be used, for example, in a measurement system that generates information regarding the inclination of the surface of an object.

Explanation of Signs

[0175] 10 Object 10s Surface 12 Sample Stage 12s Surface 14 Rotation Stage 20, 20a, 20b Light Source 30 Light Detection Device 40 Storage Device 50 Display Device 50a Input UI 50b Display UI 60 Processing Circuit 62 Memory 100 Measurement System

Claims

1. obtaining spectral information of light from the surface of an object; obtaining reference information including information on the light reflection characteristics of the surface of the object; generating information regarding the inclination of the surface of the object based on the spectral information and the reference information; A method comprising the steps of.

2. The spectral information includes a plurality of light intensities respectively corresponding to a plurality of wavelength bands, The reference information includes at least one of an incident angle of light incident on the surface of the object and an exit angle of light exiting from the surface of the object, and information indicating a relationship between the at least one angle and the plurality of light intensities respectively corresponding to the plurality of wavelength bands corresponding to the at least one angle, The method according to claim 1.

3. The information regarding the inclination of the surface of the object is information indicating the inclination angle of the surface of the object or information indicating the amount of deflection of the surface of the object, according to the method of claim 1 or 2.

4. including determining whether the inclination angle or the amount of deflection is within an allowable range, The method according to claim 3.

5. when it is determined that the inclination angle or the amount of deflection is within the allowable range, further including analyzing the surface of the object based on the spectral information, The method according to claim 4.

6. when it is determined that the inclination angle or the amount of deflection is not within the allowable range, further including generating error information, The method according to claim 4.

7. when it is determined that the inclination angle is not within the allowable range, further including generating information for correcting the inclination angle, The method according to claim 4.

8. before generating the information regarding the inclination of the surface of the object, further including determining whether the inclination angle or the amount of deflection can be estimated based on the spectral information and the reference information, The method according to claim 3.

9. the light from the surface of the object is light from one or more portions within the surface of the object, further including displaying a GUI for a user to specify the one or more portions within the surface of the object, The method according to claim 1 or 2.

10. before obtaining the reference information, further including generating the reference information, Generating the reference information includes, A first operation of changing at least one of an incident angle of light incident on the surface of the object and an exit angle of light exiting from the surface of the object, a second operation of causing a light source to emit light for irradiating the surface of the object, and a light detection device to detect light from the surface of the object and repeatedly execute a third operation of generating spectrum information of the light, associating and storing at least one of the changed incident angle and the exit angle and the spectrum information obtained by repeatedly executing the first operation, the second operation, and the third operation, including The method according to claim 1 or 2.

11. further including irradiating the object with irradiation light including light corresponding to each of the plurality of wavelength bands, wherein the light from the surface of the object is light caused by the irradiation light, The method according to claim 2.

12. A light detection device that detects light from the surface of an object and generates spectrum information of the light, a processing circuit that acquires the spectrum information from the light detection device, acquires reference information including information on a light reflection characteristic of the surface of the object, and generates information on an inclination of the surface of the object based on the spectrum information and the reference information, A system comprising:

13. further comprising a storage device that stores the reference information, wherein the processing circuit acquires the reference information from the storage device, The system according to claim 12.

14. A method executed by a computer, comprising: acquiring first spectrum information included in first light from a first region of the surface of an object; acquiring reference information including information on a light reflection characteristic of the surface of the object; determining whether an inclination of the surface of the object is within a predetermined range based on the first spectrum information and the reference information; when it is determined that the inclination is within the predetermined range, acquiring second spectrum information included in second light from a second region on the surface, and determining whether an appearance of the object with respect to color is good or bad based on the second spectrum information; An information processing method including:

15. wherein the second region is wider than the first region, The information processing method according to claim 14.

16. When it is determined that the inclination of the surface of the object is not within a predetermined range based on the first spectral information and the reference information, further including generating correction information for correcting the inclination of the surface The information processing method according to claim 14

17. Determining whether it is possible to estimate a quantity related to the inclination based on the first spectral information and the reference information When it is determined that it is possible to estimate the quantity related to the inclination, determining whether the inclination is within the predetermined range including The reference information includes range information indicating a range in which the light intensity corresponding to each of a plurality of wavelength bands can change according to a quantity related to the inclination Whether it is possible to estimate the quantity related to the inclination is determined based on the light intensity corresponding to each of the plurality of wavelength bands included in the first spectral information and the range information The information processing method according to claim 14

Images