156 results about "Specular reflection" patented technology

The invention discloses a magnetic material defect detection system based on image recognition, which adopts a first acquisition module, a first determination module, a second determination module, a second acquisition module and a third acquisition module, and is characterized in that the first acquisition module is used for performing multi-angle illumination control on the surface of a magnetic material by adopting a polarized light imaging device; mirror reflection generated by the strong light reflection characteristic is inhibited by adjusting the angle of a polaroid and the incident angle of a light source, original image data with uniform illumination distribution are obtained, and if it is detected that an overexposure area exists in an image, exposure parameters and the polarization angle are automatically adjusted to obtain a high-quality image suitable for follow-up processing; and the first determination module is used for performing multi-scale wavelet transform decomposition according to the acquired high-quality image, identifying a surface defect area by analyzing texture features and edge information in different frequency components, and judging that the surface defect area is a potential defect area if a wavelet coefficient in the high-frequency component exceeds a preset threshold value. The detection performance is obviously improved.

The invention discloses a visual combined infrared precast beam appearance defect detection method, and relates to the technical field of civil engineering structure detection and nondestructive testing, and the method comprises the following steps: establishing an illumination time sequence observation layer, collecting multi-dimensional optical parameters aiming at the surface of a precast beam, and generating a dynamic reflection fingerprint baseline; and performing coherent phase decomposition based on the dynamic reflection fingerprint baseline, separating the specular reflection signal from the material texture signal, and calibrating light spot track and intensity evolution data in the unified baseline. According to the method, an illumination time sequence observation layer is constructed to generate reflection fingerprints, coherent phase decomposition and anti-fact playback are combined, reflection interference is stripped, and crack boundaries are recovered; time coordinates are reconstructed through double-mirror-image anchor points, and crack evolution is accurately recovered; phase conjugate projection and light field traction are combined, a dynamic threshold optical fence is established, the exposure rhythm is controlled in a closed-loop mode, and precise detection of the defects of the precast beam is achieved.

The invention discloses a photovoltaic POSS (polyhedral oligomeric silsesquioxane)-containing antireflection film coating liquid and a preparation method thereof, the coating liquid comprises the following raw materials in parts by weight: 80-100 parts of modified emulsion, 10-15 parts of modified graphene, 3-5 parts of sodium dodecyl benzene sulfonate, 1-3 parts of triethylene tetramine and 40-60 parts of deionized water, a modified additive in the coating liquid contains a polyhedral oligomeric silsesquioxane structure, the polyhedral oligomeric silsesquioxane structure can form uniformly-distributed nanopores and is matched with a two-dimensional honeycomb lattice structure in the graphene oxide, the surface roughness can be increased, the microstructure can scatter incident light and reduce specular reflection, so that the surface light transmittance is improved, and meanwhile, the modified additive molecule contains a fluoroalkyl structure, so that the surface light transmittance is improved. The fluoroalkane has a high refractive index, so that light reflection can be reduced, and the light transmittance is further improved.

The invention discloses an efficient three-dimensional scene anti-rendering method and system based on a multi-view image and a storage medium, and the method comprises the steps: employing a neural symbol distance function network as a geometric model to represent a scene geometric structure of the multi-view image, decomposing a neural radiation field into a diffuse reflection field and a specular reflection field, in combination with the self-shielding probability of the mirror reflection field, the diffuse reflection field, the mirror reflection field and the self-shielding probability of the mirror reflection field, calculating color information of the spatial points and optimizing the geometric model; a material network is adopted to represent albedo and roughness and obtain material information, color information cached in a neural radiation field, an illumination visibility function and direct illumination are introduced, global illumination of each light ray is calculated, importance sampling and illumination Monte Carlo integral are combined to obtain a rendering result, and the material network and a direct illumination network are optimized; and on the basis of the geometric structure, the material information and the illumination information obtained by the decoupled geometric model, the material network and the direct illumination network, a high-quality image is generated by adopting rendering pipeline calculation.

The invention discloses a borehole optical image crack intelligent quantification method for diaphragm wall quality evaluation, belongs to the technical field of diaphragm wall quality, and aims to solve the problems of difficulty in micro crack identification, high subjectivity of geometric feature quantitative judgment and low detection efficiency in manual detection. Comprising the following steps: acquiring a high-definition image of a borehole wall, eliminating mirror reflection through adaptive homomorphic filtering, and generating an illumination invariance image; inputting a U-Net + + network (a crack segmentation model) fused with a histogram of oriented gradient enhancement module, and identifying a result containing width; a crack pixel of 0.1 mm; the length, the bifurcation angle and the tendency are calculated through fracture topology connectivity analysis; predicting a potential penetration path in combination with a soil stress field model; calculating an index representing the integrity of the diaphragm wall according to the segmentation result, the geometric features and the potential path; and generating a crack risk assessment report based on the index.

A measuring apparatus includes an illuminator including a light source to emit light onto an object being conveyed in a conveyance direction; a first diffuser plate; a second diffuser plate between the first diffuser plate and the object; a light shield portion between the second diffuser plate and the object; and a light receiver to receive light specularly reflected from the object illuminated by the illuminator. The light shield portion has an opening that includes an optical axis of light emitted from the light source and reaching the second diffuser plate.

The invention relates to a method for calculating the degree of polarization of complex space debris, in particular to a method for calculating the degree of polarization of complex space debris based on a micro-facet pBRDF model, and solves the technical problem that an existing method for calculating the degree of polarization is poor in authenticity and accuracy. According to the complex space debris polarization degree calculation method based on the micro-facet pBRDF model provided by the invention, aiming at the characteristics of multi-shape and multi-material coupling of complex space debris, on the basis of the modeling thought of complex refractive index, specular reflection, diffuse reflection and volume scattering of different structural materials of the complex space debris; the albedo projection area is adopted as a reflection contribution coefficient calculated by the total light intensity of reflected light of the complex space debris, and a micro-surface element pBRDF model of different structures and different reflection contribution coefficients of the complex space debris is established, so that the model is closer to the multi-shape and multi-material characteristics of the real space debris; and the polarization degree of the complex space debris calculated based on the micro-facet pBRDF model is more accurate.

The invention discloses a visual inspection sorting method and system for surface defects of intelligent electric meter shell injection molded parts, and relates to the technical field of visual inspection, and the method comprises the following steps: selecting an intelligent electric meter shell as a reference part, dividing the surface of the shell into a plurality of functional partitions, collecting structured light form and brightness information, and obtaining a reference appearance map; and positioning a to-be-detected electric meter shell to a position consistent with the reference part, obtaining the online three-dimensional form and brightness response of each functional zone, mapping the online three-dimensional form and brightness response to the reference appearance map, marking a stable mirror surface with high brightness, and interpolating along an observation track to generate an online appearance map. According to the invention, through functional partition sampling layout of a window sealing area, a wiring terminal area, a stud and reinforcing rib area, a nameplate and two-dimensional code area and a general decoration side wall area, and in cooperation with double-light-source collection of diffused light and oblique incident light combined with structured light, a reference appearance map containing a highlight tolerance mask is constructed; stable characterization of mirror reflection and a transparent window is realized, and false detection caused by high brightness of the mirror surface is remarkably reduced.

The invention belongs to the field of semiconductor metering, and discloses an X-ray critical dimension system calibration method, which comprises the following steps of: firstly, moving a group of oppositely moving slit blade edges of high-flux small-angle X-ray scattering instrument equipment, recording flux change, and calibrating the relative distance of the initial positions of the group of slit blade edges; setting a slit opening, and calibrating the positions of the slit center and the light beam center; then adjusting the grazing incidence angle of the sample until the intensity peak of the specular reflection light coincides with the Yoneda peak of the critical angle, and recording the incidence angle at the moment as the critical angle; recording light spots of an incident light beam directly irradiated on the detector, comparing scattered light spots with different pitch angles, and calibrating the pitch angle corresponding to the light spots on the same horizontal plane as the direct light spots as a pitch angle zero position; and finally, a light spot of the detector is observed, when a complete semicircle is formed, the semicircle is calibrated as an azimuth angle zero position, different azimuth angle values are obtained through building and combining, and the in-situ calibration requirements of rapid, non-destructive and accurate measurement of the three-dimensional morphology of the complex IC nano-structure are met.

A measuring apparatus includes an illuminator and a light receiver. The illuminator includes a light source to emit a light beam to an object conveyed in a conveyance direction; and a diffuser plate to diffuse the light beam emitted from the light source to illuminate a surface of the object with a diffused light beam. The light receiver receives reflection light specularly reflected from the surface of the object illuminated by the illuminator. A conditional expression below is satisfied:L1>L2whereL1 denotes a distance between the light source and the diffuser plate, andL2 denotes a distance between the diffuser plate and the surface of the object.

The invention discloses a composite aluminum foil current collector coating thickness detection device, and relates to the technical field of coating thickness detection, the composite aluminum foil current collector coating thickness detection device comprises a thickness detection member, the thickness detection member comprises an upper wheel set, a lower wheel set, a detection rack and a laser detector, and the upper wheel set and the lower wheel set are respectively penetrated by an upper shaft and a lower shaft; the detection frame and the lower shaft rotate synchronously to change the inclination angle of the laser detector, and the tensioning wheel can ascend and descend to be used for adjusting the tightness of the composite aluminum foil on the lower wheel set. The two sides of the aluminum foil are clamped and the aluminum foil is transversely stretched, so that the aluminum foil is flatly attached to the measuring wheel. It is ensured that the aluminum foil is in a flat, tight and vibration-free state when passing through a laser measurement point, which is the premise of obtaining accurate measurement data. The whole laser detection frame can be used as a whole, the lower shaft supported by the aluminum foil synchronously rotates to change the angle of incident light, so that a specular reflection light path of ambient light deviates from the laser receiver, laser beams can still keep nearly vertical incidence, and reflected light of the laser beams can be effectively received.

The invention discloses an agricultural plant protection unmanned aerial vehicle path planning method and system, and relates to the technical field of agricultural unmanned aerial vehicle flight control, and the method comprises the following steps: S100, constructing an illumination and time sequence observation layer, collecting an incident angle, a polarization parameter and brightness gradient information from an operation environment, generating a light spot risk baseline according to the information, and establishing a time anchor point for dynamic identification. According to the method, a light spot risk baseline is constructed based on multi-source illumination, mirror reflection is stripped, abnormal tracks are identified, false obstacles are calibrated, a reverse illumination mask is generated to serve as a path boundary, task perception information is fused to update weights, differential privacy is introduced to correct deviation, and a reverse phase light graph and a shadow beacon are combined. Dynamic traction and closed-loop regulation and control of an unmanned aerial vehicle path are realized, and planning precision and flight safety are improved.

The invention discloses a humidity response discoloration radiation refrigeration material which comprises a scattering layer and an iridescent photon film arranged on the surface of the scattering layer, the iridescent photon film is a cellulose nanocrystal / polyethylene glycol composite film, and the scattering layer is a polylactic acid-silicon dioxide-aluminum oxide composite nanofiber film. Through the composite design of the top cellulose nanocrystal / polyethylene glycol iridescent photon film and the bottom PLA / SiO2 / Al2O3 scattering layer, coupling of color mirror reflection of the color radiation refrigeration function layer constructed by CNC / PEG composite and broadband diffusion response of the electrostatic spinning film reflecting layer is achieved, and the negative effects of moisture absorption and color development on the reflectivity are reduced; color intelligent response and efficient radiation refrigeration are successfully combined; the preparation method is simple in process, the adopted raw materials are all degradable and renewable materials, the cost is low, and industrial popularization and application are easy.

To provide a measuring apparatus capable of improving accuracy in measuring an object to be measured.SOLUTION: The measuring apparatus according to one aspect of the present invention is a measuring apparatus for measuring an object to be measured conveyed in a conveying direction, and includes: an illumination unit for illuminating the object to be measured and a light receiving unit for receiving specularly reflected light from the object to be measured illuminated by the illumination unit. The illumination unit includes: a light source including a plurality of point light sources; and a first diffusion plate, the light source being arranged in a plurality along a predetermined arrangement direction, the plurality of point light sources being arranged in an orthogonal direction orthogonal to the arrangement direction. When the diffusion angle of the first diffusion plate in the arrangement direction is defined as Ax and the diffusion angle in the orthogonal direction is defined as Ay, the relationship of Ax<Ay is satisfied.SELECTED DRAWING: Figure 4

The present application provides a switchgear condensation monitoring method, device, electronic device, and storage medium, relating to the field of power monitoring technology. The method utilizes a laser to scan the condensation monitoring area on the top of the switchgear. The laser generates different types of optical signals based on the surface state of the condensation monitoring area, receives the optical signals, and collects light intensity information of the optical signals to determine whether condensation is present in the condensation monitoring area. The method also detects the first reception time of mirror-reflected light and the second reception time of refracted light, as well as the incident angle of the mirror-reflected light and the refraction angle of the refracted light, and determines the thickness of water droplets. Operation and maintenance responses are then prioritized based on whether condensation is present in the condensation monitoring area and the thickness of the water droplets. Thus, by collecting the intensity of reflected light and calculating the thickness of water droplets, the condensation situation inside the switchgear can be accurately reflected, improving the accuracy of condensation monitoring while also providing comprehensive early warnings and facilitating efficient maintenance.

A multilayer coating film includes a lustrous layer containing a luster material, and a colored layer stacked on the lustrous layer, containing a reddish coloring agent, and having translucency. For the lustrous layer, when a light incident angle (an angle with respect to a line perpendicular to the surface of the lustrous layer) is 45° and L*(θ) represents the L* value of the lightness index of reflected light measured at a light receiving angle (the angle of inclination toward a light source side from a specular reflection direction) θ, L*(θ) at 45°≤θ≤80° and 100°≤θ≤110° is 10 or less, and when the luster material is projected onto the bottom surface of the lustrous layer, the percentage of the projected area of the luster material on the bottom surface is 3% or more to 70% or less per unit area.

This invention discloses a robust method, device, and storage medium for laser spot recognition and tracking in complex lighting environments, belonging to the field of computer vision and target detection. Addressing the problems of high false alarm rates and poor robustness in existing methods under interference such as strong ambient light, dynamic projector flicker, and specular reflection, this invention proposes a multi-layered processing framework of "detection-verification-tracking." First, adaptive threshold segmentation is performed on the current frame image to extract candidate regions with brightness higher than the background. Second, multi-dimensional feature verification is introduced. Based on the inherent physical properties of the laser spot (such as spectral matching degree, shape and size, and two-dimensional Gaussian intensity distribution) and temporal motion patterns, candidate regions are jointly verified and filtered to effectively remove various homogeneous and heterogeneous interferences. Finally, through a multi-target trajectory management module, the filtered candidate spots are correlated with historical trajectories (e.g., using the Hungarian algorithm), and combined with Kalman filter prediction and state machine-based trajectory lifecycle management (temporary, confirmed, lost, terminated), stable tracking and output of the laser spot are achieved. This invention does not rely on a large amount of training data, has high computational efficiency, and can significantly improve the accuracy and robustness of laser spot recognition under complex dynamic lighting conditions, providing a reliable front-end perception guarantee for vision-based high-precision laser spatial positioning and interaction systems.

This invention discloses a bimetallic hybrid metasurface that achieves polarization-selective absorption and tunable liquid immersion. The metasurface consists of a three-layer structure: a bimetallic hybrid layer, a silicon dioxide layer, and a silver reflective layer. The bimetallic hybrid layer is composed of aluminum and titanium nanoribbons. The bimetallic hybrid metasurface achieves perfect absorption of incident light under x-polarized light at the resonant wavelength and specular reflection of incident light under y-polarized light, thus exhibiting a high extinction ratio. Furthermore, the absorption peak wavelength of the metasurface can be continuously and dynamically tuned by adjusting the unit period of the metasurface or by utilizing active tuning through liquid immersion. The bimetallic hybrid metasurface proposed in this invention achieves high-contrast polarization-selective absorption and possesses advantages such as simple structure, ease of integration, and dynamic tunability, thus it can be widely applied in practical applications such as novel optical polarizers and photodetectors.

The application discloses a method for inverting marine aerosol optical depth by using spaceborne lidar noise, belongs to the technical field of laser remote sensing, and is used for quantitatively inverting aerosol optical depth. Under the premise that system hardware parameters of the spaceborne lidar and total background noise data detected by the spaceborne lidar, environmental parameters of a corresponding region and moment are given, a noise model of solar radiation items corresponding to water surface white froth diffuse reflection and water surface specular reflection, a water-leaving noise model (a noise model of solar radiation items of water body backscattering), and an atmospheric noise model (a noise model of solar radiation items of Rayleigh scattering of atmospheric molecules and Mie scattering of aerosol particles) are respectively constructed. Water surface noise, water-leaving noise and atmospheric Rayleigh scattering noise are removed from total noise rate of the atmosphere top detected by the lidar, and aerosol scattering noise results are obtained. Finally, marine aerosol optical depth of a satellite transit region and moment is quantitatively inverted by using the aerosol scattering noise results and the aerosol scattering noise model.

This invention discloses a detection method, system, and medium based on line spectral confocalization. The method includes: determining the number of peaks; if the number of peaks is one, adjusting the light intensity value corresponding to the peak wavelength to be within the light intensity working range; if the number of peaks is not less than two, extracting the light intensity value corresponding to the peak wavelength, analyzing the peak morphology, and identifying the peak wavelength associated with each reflection region; analyzing the offset of the height of the specular reflection region, correcting the detection height of the specular reflection region to obtain the height difference between the reflection regions covered within the width of the line spot at any position on the scanning line; and adjusting the distance of the sensor relative to the surface of the object under test according to the height difference, so that there is one and only one valid peak in the spectral image at any position on the scanning line. This invention can accurately calculate the height difference between the specular reflection region and the diffuse reflection region covered within the width of the line spot, improving the signal-to-noise ratio of the spectral image and expanding the application scenarios.

To provide a measuring apparatus capable of performing highly accurate measurement.SOLUTION: The measuring apparatus according to one aspect of the present invention is a measuring apparatus for measuring an object to be measured conveyed in a conveying direction, and includes: an illumination unit for illuminating the object to be measured and a light receiving unit for receiving specularly reflected light from the object to be measured illuminated by the illumination unit. The illumination unit includes a diffusion plate for diffusing a light flux from a light source. When the distance between the light source and the diffusion plate is defined as L1 and the distance between the diffusion plate and the object to be measured is defined as L2, the relationship of L1>L2 is satisfied.SELECTED DRAWING: Figure 7

The invention discloses a metal truss antenna housing and a design method thereof, and belongs to the field of radar antennas. In order to solve the problem that an antenna radiation pattern of an existing antenna housing is seriously distorted, the metal truss antenna housing comprises a metal framework and a skin arranged on the surface of the metal framework, the metal framework is of a truss structure, and a first section of at least part of rod pieces in the metal framework comprises a connecting part. The reflecting part is connected with the connecting part; the reflecting part is used for realizing non-mirror scattering between a reflected wave and the first cross section of the partial rod piece; the connecting part is used for realizing the connection between the rod pieces, and the first cross section is the cross section of one side, facing the antenna, of the rod piece. According to the metal truss, mirror reflection is converted into non-mirror scattering through the arrangement of the reflection part, so that distortion of an antenna pattern is effectively suppressed, particularly, raising of a far-region minor lobe level and loss of main lobe gain are reduced, and meanwhile, the original high-strength advantage of the metal truss is completely reserved through the arrangement of the connection part.

The invention discloses a manufacturing method of a high-power photovoltaic module, and aims to solve the technical problems that specular reflection on the lower surface of glass of an existing crystalline silicon photovoltaic module causes light loss, the utilization rate of ultraviolet light is low, and aging of a packaging adhesive film is easily accelerated. The method comprises the following steps: firstly, carrying out hydrofluoric acid etching or micron-order fusion embossing treatment on the lower surface of photovoltaic front glass to form a concave-convex light trapping structure so as to reduce mirror reflection of incident light; the upper surface of the glass is coated with a polyfluorene down-conversion material layer with the thickness of 50-100 nm, and ultraviolet light is converted into high-responsivity blue light. Subsequent procedures of cell scribing, multi-main-grid series welding, POE adhesive film lamination, EL and appearance detection, vacuum lamination, trimming and framing and the like are carried out to complete assembly preparation. Tests show that in a 66-version assembly, only the lower surface of the glass is treated, so that the power can be improved by 2.1 W compared with that of a traditional process, the power is improved by 5.8 W after the lower conversion film layer is overlaid, meanwhile, the aging effect of ultraviolet light on the adhesive film is weakened, the service life of the assembly is prolonged, and the process is compatible with an existing production line and has remarkable industrial application value.

The invention relates to an organic solid waste pyrolysis device utilizing mirror reflection to gather solar energy and an operation method.The device is composed of a light reflection module, a heat transfer module, a heating module and a sample placing room, the light reflection module is composed of eight reflectors arranged around the sample placing room by 360 degrees and can reflect the solar energy to a heat collection plate, and the heat transfer module is used for transferring heat to the sample placing room; the heat collection plate converts solar energy into heat energy and transmits the heat energy to the heating module. The heating module is composed of a heating column and a heating disc and can evenly heat the sample placing room. Solar energy is gathered through the light reflecting mirror and the heat collecting plate and converted into heat energy, the heat energy is transmitted into the inner container through the heating column, and organic solid waste is pyrolyzed. The sample placing room adopts a sealing design, and temperature monitoring and automatic regulation and control are carried out through a temperature sensor and a heat radiation instrument. The device has a good solar energy utilization rate and a uniform heating effect, and can perform pyrolysis of organic solid wastes in an efficient and environment-friendly manner so as to achieve the purpose of resource utilization of the wastes.

A measurement apparatus for measuring a measurement target object conveyed in a conveyance direction, the measurement apparatus including: an illumination unit configured to illuminate the measurement target object; and a light receiving unit configured to receive specular reflection light from the measurement target object illuminated by the illumination unit. The lighting unit includes a light source including a plurality of point light sources arranged in a predetermined arrangement direction, the plurality of point light sources being arranged in an orthogonal direction orthogonal to the predetermined arrangement direction, and a first diffusion plate disposed in the orthogonal direction. When a diffusion angle of the first diffusion plate with respect to the predetermined arrangement direction is given as Ax, and a diffusion angle with respect to the orthogonal direction is given as Ay, a relationship of Ax < Ay is satisfied.

To accurately identify the shapes of objects.SOLUTION: A method and system for eliminating 2D features from planar surfaces in 2D images are provided. A single camera at a fixed position takes three digital images of a subject such as a pallet of boxes. One image (IA) is taken with ambient lighting, one image (I1) is taken with ambient lighting plus a first added light source, and one image (I2) is taken with ambient lighting plus a second added light source. An output image Q is computed by Q=(I1-IA) / (I2-IA). Subtracting the ambient image removes ambient diffuse and specular reflections. Division eliminates all variations in the output image caused by color. The only variations that remain are due to the angle between each surface point's normal direction and the direction from the light to that point. The output image Q, devoid of all colors and 2D features, is well suited for computing a robot grasp of an object in the image.SELECTED DRAWING: Figure 5

The present invention teaches a real-time hybrid ray tracing system for non-planar specular reflections. The high complexity of a non-planar surface is reduced to low complexity of multiple small planar surfaces. Advantage is taken of the planar nature of triangles that comprise building blocks of a non-planar surface. All secondary rays bouncing from a given surface triangle toward object triangles keep a close direction to each other. A collective control of secondary rays is enabled by this closeness and by decoupling secondary rays from primary rays. The result is a high coherence of secondary rays.

The invention relates to the technical field of machine vision detection, and discloses a pneumatic valve block surface cleanliness detection method based on machine vision, and the method comprises the following steps: S1, based on the characteristics that the surface of a pneumatic valve block is strong in light reflection and diversified in pollutant type, adopting three light source modes of annular polarized light, low-angle dark field illumination and coaxial white light, millisecond-level synchronous imaging is carried out on the same valve block area through the beam splitter prism and the three-way synchronous triggering camera, and a multi-mode original image set is generated. Polarization inhibition reflection, dark field scattering enhancement and bright field uniform illumination are integrated through a multi-mode light source synchronous acquisition mechanism, the limitation of single light source imaging is overcome, metal surface specular reflection interference is effectively eliminated, the detectability of low-contrast pollutants such as oil stains is effectively improved, and the detection efficiency is improved. And dynamically weighting high-frequency edge and low-frequency texture components by an adaptive wavelet fusion strategy.

This electronic auscultation device comprises: a diaphragm that vibrates, when in contact with a living body which is an object to be measured, together with the living body, the diaphragm having a light reflection part provided on a surface of the diaphragm opposite to a contact surface that contacts the object to be measured; a light source; a light receiving element that has a light receiving surface for receiving light emitted from the light source and specularly reflected by the light reflection part, and generates a signal corresponding to an amount of light reaching the light receiving surface; a selection unit that selects any of a plurality of modes including a first mode in which biological vibration including a first frequency band is measured, and a second mode in which biological vibration including a second frequency band lower than the first frequency band is measured; and a sensitivity adjustment unit for adjusting a sensitivity of the light receiving element. The sensitivity adjustment unit adjusts the sensitivity of the light receiving element so as to have a first sensitivity when the first mode is selected by the selection unit, and adjusts the sensitivity of the light receiving element so as to have a second sensitivity lower than the first sensitivity when the second mode is selected by the selection unit.

According to the present disclosure, there is provided a technique capable of suppressing an erroneous detection of a presence or absence of a substrate caused by a light receiver receiving a specularly reflected light. There is provided a technique that includes: a holding structure provided with a placing surface capable of accommodating a substrate thereon; a light detector including: a light emitter arranged to irradiate an irradiation light toward a back surface of the substrate placed on the placing surface; and a light receiver arranged to be capable of receiving a diffusely reflected light of the irradiation light irradiated from the light emitter without receiving a specularly reflected light of the irradiation light; and a controller configured to be capable of determining a presence or absence of the substrate based on a light receiving state of the light receiver.