Abstract: A method and system for inspecting parts utilizing triangulation are provided. The system includes a part support subsystem including a fixture for supporting a part to be inspected and a head apparatus. The head apparatus includes at least one radiation source for directing a plane of radiation at the part so that the part occludes the plane of radiation to create unobstructed planar portions of the plane of radiation wherein each of the unobstructed planar portions of the plane of radiation contains an amount of radiation which is representative of a respective geometric dimension of the part. The head apparatus also includes at least one receiver module for measuring the amount of radiation present in each of the unobstructed planar portions and a triangulation-based sensor to illuminate the part with a beam of electromagnetic energy to obtain a reflected beam of electromagnetic energy and to sense at least one portion of the reflected beam of electromagnetic energy.

Abstract: An on-board object detector and on-board object detection method for detecting an object present in a pickup image at a high level of precision. A controller controls a projector to irradiate a line of light while shifting the irradiation angle, and images in the coverage area of the line of light are captured for multiple frames using a camera. Then, shifts in the moving speed of the line of light in the images across the frames are computed based on the images captured, and shifting points in the moving speed of the line of light are detected based on the computed shifts in the moving speed of the line of light in the images across the frames. The position and size of an object that is present in the images are specified based on said detected shifting points in the moving speed of the line of light.

Abstract: The present invention provides an optical displacement meter in which light receiving elements are disposed two-dimensionally, capable of stably obtaining a reception light amount in accordance with a work.

Abstract: A method of measuring a three-dimensional shape of a connection assembly of a stator coil in a turbine generator, includes first measuring a three-dimensional shape of a measurement area of the connection assembly of the stator coil in a measurement range set in advance by a laser non-contact three-dimensional shape measurement device, second measuring a three-dimensional shape of a measurement area of the connection assembly of the stator coil in a measurement range set in advance by a multi-joint contact three-dimensional shape measurement device, the multi-joint contact three-dimensional shape measurement device including a plurality of arms being coupled via a joint including a built-in encoder, and integrally synthesizing the three-dimensional shape data measured in the first measurement, the three-dimensional shape data measured in the second measurement, and shape measurement data of a local area measured manually, thereby drafting a plan of the stator connection assembly.

Abstract: For objects with non-Lambertian surfaces, an object surface is mapped by effectively modifying the reflective properties of the object surface being sensed. By effectively making the surface Lambertian with high albedo, a calibration imaging task is achieved using a typical camera from a single or small number of camera positions. The calibration method temporarily modifies the surface properties of the imaged object by applying a thin and opaque layer, such as a coating, covering, or veneer, to the object for the duration of the calibration imaging task. The surface of this layer is a Lambertian reflector, with medium to high albedo. The layer is snugly applied, so a shape of the layer is as close as possible to that of the surface. Once the layer is applied, imaging of the layer surface essentially yields the same shape as the underlying object.

Abstract: A three-dimensional shape measuring system is provided with a measuring unit having a three-dimensional measurement range and adapted to measure the three-dimensional shape of a measurement object in a noncontact manner, a measurement range shifting unit for shifting the position of the measurement range of the measuring unit, a shape calculating unit for calculating the overall three-dimensional shape of the measurement object from a plurality of measurement data obtained by shifting the measurement range relative to the measurement object, and a judging unit for setting judgment areas in specified peripheral areas within the measurement range and judging the presence or absence of any unmeasured area of the measurement object outside the measurement range based on measurement data corresponding to the judgment areas.

Abstract: The present invention provides an optical displacement meter which performs a profile search for performing positional adjustment of a profile shape.

Abstract: A method of inspecting an inspection target surface comprises: irradiating an irradiation light having a predetermined pattern on the inspection target surface; imaging the surface irradiated with the irradiation light; and inspecting the inspection target surface based on an obtained image of the inspection target surface. The irradiation light irradiated from an irradiation face has a mesh-like pattern including meshes of a same shape. Each mesh has an irradiation area smaller than a non-irradiation area in a plane normal to the optical axis. The inspection target surface is inspected based on lightness/darkness information of an image area in the obtained image corresponding to a non-irradiated area in the inspection target surface. A light point having intermediate brightness and formed in a dark face formed within the mesh is extracted as a defect candidate.

Abstract: In a matrix of light detectors forming a part of a three-dimensional measurement sensor, outputs of light detectors belonging to a same row are connected to a common signal line. An output of each light detector is read, through scanning by the horizontal scan circuit, to the signal line from left to right in order, during a horizontal scan period which is sufficiently short such that slit light of a light-sectioning method can be assumed to be substantially stationary. A position detector determines a time from start of the horizontal scan period until detection of a maximum peak of a signal in the signal line. The time indicates a distance from an end of the row from which scanning is started to the light detector detecting the peak of the slit light. A recording processor records a value of a distance determined by the position detector in correspondence to a value of a counter indicating a projection angle of the slit angle.

Abstract: A system for measuring an object and for monitoring the surface of the object. The system comprises at least a first subsystem for determining one or more dimensions of the object and a position of the object within the first subsystem, and at least a second subsystem for determining a surface structure of the object. Further, the system comprises a control unit generating control signals (iii) for operation of the second subsystem as a function of data (i) of the first subsystem with respect to a position of the object in the first subsystem and/or the dimension of the object, and of data (ii) of the second subsystem with respect to a position of the camera device in the second subsystem.

Abstract: A method of dynamically imaging, calibrating and measuring bump height and coplanarity of a plurality of bumps on a surface is disclosed. The method includes illuminating the plurality of bumps with multispectral light from at least one light source, and receiving light of a first wavelength at an imaging device such that a top view image of at least a portion of the plurality of bumps is captured. The light of the first wavelength is reflected off the plurality of bumps at a first angle from the surface. Light of a second wavelength is received at the imaging device such that at least one oblique side view image of at least a portion of the plurality of bumps is captured. The light of the second wavelength is reflected off the plurality of bumps at a second angle from the surface. The captured images are processed to determine absolute bump height and coplanarity. A corresponding apparatus is also disclosed.

Abstract: A method and apparatus for optically scanning a pneumatic tire of a vehicle wheel that is rotatably mounted on a measuring shaft of a wheel balancing machine. A light source, such as a laser beam source, is provided to emit at least one light beam onto the surface of the pneumatic tire, which is reflected by the surface and received by a receiver. In response, the receiver produces position signals based on the impingement point of the reflected beam for evaluation by a computer-aided evaluation device. Rotary angle signals representing the rotational angle of the wheel are supplied to the computer-aided evaluation device by a rotary angle sensor. The computer-aided evaluation device determines dimensions and positions of the pneumatic tire or its constituent parts based on the positional signals and the rotary angle signals.

Abstract: There is provided a three-dimensional shape detecting device comprising: pattern beam projection means which projects a plurality of pattern beams including two pattern beams having different angular widths; image capturing means which captures an image of a subject onto which the pattern beams are projected, from a position a prescribed distance apart from the pattern beam projection means; and three-dimensional shape calculation means which calculates positions of the pattern beams projected on the subject based on the image captured by the image capturing means and thereby determines a three-dimensional shape of the subject.

Abstract: A system optically detects and measures release agent on a rotating image member in an ink jet printer. The system includes a collimated light source oriented to direct a collimated beam of light generated by the source towards a rotating image member, an image sensor for generating an image of a portion of the rotating image member from a portion of the collimated beam of light reflected by the rotating image member, an image differentiator for measuring a difference between a first image generated by the image sensor and a second image generated by the image sensor, and a release agent measurement generator that is coupled to the image differentiator to receive the difference between the two images and to generate a measurement of the release agent on the rotating image member.

Abstract: A method for the processing of a profile of a solid which has been detected, dynamically, for the purpose of determining wear which has occurred. The data from the evaluated profile are used as a control variable for controlling at least one machine for surface machining on the solid.

Abstract: The present invention relates to a method for contactless dynamic detection of the profile of a solid body, particularly a moving one, a laser beam, expanded to form a linear light band, from a laser device being projected onto a region of the surface of the solid body, and the light reflected therefrom being focused in an imaging device, whose optical axis is at a fixed triangulation angle to the projection direction of the laser device and that is arranged at a fixed base distance from the laser device, and is detected by means of a planar light receiving element, in particular at a frequency that is high by compariosn with a speed of movement of the solid body, whereupon signals output by the light receiving element are used in a data processing device as a function of the triangulation angle and the base distance to obtain the measured values of the profile by means of geometric relationships, the values being stored as a profilogram.

Abstract: A laser scanner computes a range from a laser line to an imaging sensor. The laser line illuminates a detail within an area covered by the imaging sensor, the area having a first dimension and a second dimension. The detail has a dimension perpendicular to the area. A traverse moves a laser emitter coupled to the imaging sensor, at a height above the area. The laser emitter is positioned at an offset along the scan direction with respect to the imaging sensor, and is oriented at a depression angle with respect to the area. The laser emitter projects the laser line along the second dimension of the area at a position where a image frame is acquired. The imaging sensor is sensitive to laser reflections from the detail produced by the laser line. The imaging sensor images the laser reflections from the detail to generate the image frame.

Abstract: The invention relates to a three-dimensional measurement system comprising a hardware part and a software part, in which the hardware part includes a mobile two-axis assembly (12) associated with a remote measurement device (13) installed on a fixed part (14), each axis being equipped with an angular encoder (22) restoring the direction of a sighting at any time, and in which the software part includes a control part at the input and an acquisition part at the output.

Abstract: A three-dimensional shape is measured by a simple system structure. A three-dimensional shape measuring instrument comprises a device (1-1) in which a light-emitting diode (1-1b) is installed as a marker in a line laser light source (1-1a), an imaging device (1-2), and a computer (1-3). For measurement, a line laser beam from the device (1-1) is applied to an object (1-4) to be measured, the imaging device (1-2) images the applied line laser beam (1-5) and the light-emitting diode, and a three-dimensional shape is obtained from the image data by triangulation by means of the computer (1-3).

Abstract: A method and apparatus is described for contact-free 3 dimensional-measuring of a moving object with periodic motion. The method and apparatus makes use of the projection of a defined intensity pattern onto the moving object and the recording and analysis of a reflected pattern from the object wherein the intensity pattern projection is synchronized to a characteristic periodic frequency period or sub-period of the moving object.

Abstract: A method is disclosed for measuring components (1) using a measurement system (20) guided by a manipulator (10). In this process, reference features (9, 9a, . . . , 9i) are decentrally located at various positions near a component (1) to be measured, the reference features each being assigned to at least one measuring object (6) located at a close distance to the particular reference feature (9, 9a, . . . , 9i) on the component (1) to be measured. Before a test object (6) is measured, the measuring system (20) is first brought into a calibration position using the manipulator (10), and the reference feature (9, 9a, . . . , 9i) assigned to the particular test object (6) is measured using the measuring system (20) to calibrate a coordinate system of the manipulator (10). Using the manipulator (10), the measuring system (20) is then moved into a measurement position, where the relevant test object (6) is measured. A corresponding device for measuring components and a component carrier (7) are also disclosed.

Abstract: An operation of projecting slit light onto an object to be measured and receiving light reflected thereon, and an operation of acquiring a two-dimensional image concerning the object to be measured are repeated a certain number of times by changing a focal length. An imaging contrast is calculated with respect to each of areas on the two-dimensional images acquired at the different focal lengths. A high contrast area where the imaging contrast exceeds a predetermined threshold value is extracted with respect to each of the two-dimensional images acquired at the different focal lengths. Distance information concerning the respective areas is acquired by performing triangulation with respect to each of the high contrast areas. Position adjustment of measurement dimensions is performed in such a manner that the areas are included in the measurement dimensions having the predetermined measurement depth, based on the distance information.

Abstract: A method for calibrating a laser three-dimensional digitizing sensor. First, a three-dimensional coordinator X-Y-Z is defined and a calibrating surface is provided. Second, a first mapping table of a two-dimensional digital image to the Z axis is established by translating the calibrating surface along the Z axis. Subsequently, the calibrating surface rotates along the Y axis by a predetermined angle and translates along the Z axis to establish the second mapping table of the two-dimensional digital image and the X axis according to the first mapping table.

Abstract: Apparatus for sensing information regarding a surface including a first plurality of optical elements arranged to acquire two dimensional information about a surface, a second plurality of optical elements arranged to acquire topographical information about the surface, wherein the first plurality and the second plurality of optical elements are arranged to simultaneously provide the two dimensional information and the topographical information to at least partially non-overlapping portions of a single sensor array.

Abstract: A device for measuring one or more dimensions of an object. One or more light emitters direct light towards the object. At least one light blocking element, arranged between the light emitters and the object, blocks all but a bundle of light to form a light edge on the object. At least one sensor captures an image of the light edge, wherein the dimensions may be determined from image data of the sensor. The object and/or device may move relative to one another, along an axis, to change measurement location of the object.

Abstract: An arrangement for measuring components has a manipulator, at least one measuring system in operative connection with the manipulator, the at least one measuring system including at least one contour measuring device associated with the manipulator and generating an optical sensing surface sweeping a measuring region, an at least one measuring object arranged in the measuring region and at least one reference feature associated with the measuring object; and a method of measurements is performed with the arrangement.

Abstract: A method for measuring a characteristic of a substrate, including directing an incident beam at an inspection grid of points on the substrate, receiving the reflected beam with a position sensitive detector, measuring the displacement of the reflected beam from its expected location, compiling a database of the displacement measurements, examining the database for effects of a pattern induced anomaly in the displacement measurements, producing an adjusted database, and deriving the characteristic of the substrate from the adjusted database. Thus, pattern induced errors from the displacement measurements are corrected. In this manner, problems with interpreting the reflection angles of a beam in substrate stress analysis equipment are overcome where distortions in the reflection angles are caused by deposition patterns on the substrates.

Abstract: An apparatus for mounting semiconductor chips onto a substrate contains a measuring station for the contactless measurement of the height of the surface of the mounted semiconductor chip facing away from the substrate at a minimum of three locations. From this, at least one parameter is calculated that characterises the adhesive layer formed between the semiconductor chip and the substrate. A difference of the measured value to a set value is used to adjust the mounting process. An apparatus for wiring semiconductor chips also contains such a measuring station in order to determine the individual height of each connection point on the semiconductor chip. This information is used in order to lower the capillary to the respective connection point on the semiconductor chip in the shortest possible time.

Abstract: A visual sensor capable of expanding a dynamic range with a little load of processing for arithmetic operations and performing a stable detection not affected by change of conditions such as ON/OFF state of projection of reference light. A multiplying parameter A (A>1) and the number N of times of image capturing are set in accordance with ON/OFF state of the reference light projection. N images are captured with a shutter speed varying by successively multiplying an initial value by (1/A). Values of density of each pixel in the captured images are summed. Values of constants B and C in equations: 1=B·Zmax+C; 0=B·Zmin+C are obtained based on the maximum value Zmax and the minimum value Zmin of the summed values of densities of all the pixels. An output value Z? of each pixel is obtained according to an equation: Z?=B·Z+C, using the determined values of B and C.

Abstract: A non-contact surface measurement system, method and apparatus provides data to computers so that the topography of the surface of an object can be digitally recreated. 3-D images that define tool paths can be created from the data. Thus, cavities may be formed in selected materials by a tool. The appropriately selected materials safely encapsulate the object, which may be an artifact, art object, or other fragile or valuable item for moving or storage.

Abstract: A method and apparatus for using a plurality of regions of colored light to index and locate discrete targets in photogrammetry systems. The colored regions of light are used to determine a unique location on the surface of a three-dimensional object. Multiple projections of colored regions may be used to determine precise locations on the surface of the object. Each colored region may be assigned a color-numeric identified to assist in the indexing process. The process is suitable for determining the shape of aircraft, watercraft and automotive parts.

Abstract: The invention relates to a camera calibration system and method thereof which is capable of easily performing camera calibration using a concentric circle pattern. According to the invention, a method of calibrating a camera calibrates the intrinsic parameters of the camera required to measure geometric information of an object using projection invariable characteristics of concentric circles. The method includes the steps of taking images of the calibration pattern consisting of two or more concentric circles located in the same plane and having different radius at different angles to obtain projected images calculating the central point of the projected images using a given algorithm, and calculating the principal point and focal point of camera using a nonlinear minimization algorithm based on the central point thus obtained.

Abstract: A position of a honeycomb structure, which is comprised of an outer shell, separation walls arranged in the form of a honeycomb within the outer shell, and a number of axially extending cells which are defined by the separation walls, is recognized. When the position recognition is carried out, the honeycomb structure is located with the axis extending in an upward and downward direction. A camera to pickup image data is disposed out of an area directly above an upper surface of the honeycomb structure in the axial direction. Image data including the entirety of the upper surface of the honeycomb structure is picked up by the camera, so that the position of the honeycomb structure is recognized based on the image data.

Abstract: A three-dimensional inspection system and method is used to obtain information about three-dimensional articles with specular surfaces having a shape and positive or negative height by projecting a pattern of light onto the articles at an oblique angle. The system includes a patterned light projector with optical axis disposed at an oblique angle with respect to the plane of the article being inspected, an extended light source, and an image detector disposed above the article to detect the image of the pattern on the article. The light pattern includes lines with a substantially equal thickness and spacing. The spacing of the lines is greater than a spacing or pitch of the specular elements. An image processor, coupled to the image detector, receives the image, locates the lines, and measures the lateral shift of the lines. Height information is determined from the lateral shift and projection angle using triangulation.

Abstract: A beam projector is aligned with a linear array of receptors. An alignment receptor is at each end of the linear array of receptors. A beam is projected from the projector. The beam is swept until the alignment receptors sense the beam. A signal is transmitted upon each of the alignment receptors sensing the beam. The position of the beam projector is recorded in response to the transmitted signals. The alignment position of the beam projector, to align with the linear array of receptors, is computed from the recorded positions. The beam projector is aligned with the linear array of receptors according to the alignment position.

Abstract: A method and apparatus capable of using two or more capture methods to create three-dimensional representations of a target captured. Elements of the three-dimensional digital representation generated from the plural capture method are combined to yield a single digital three-dimensional representation having improved quality.

Abstract: A semiconductor integrated circuit inspecting apparatus inspecting a terminal provided on a mount surface of a semiconductor integrated circuit includes a light emitter, a photographing unit and an inspector. The light emitter emits a linear light obliquely to the mount surface. The photographing unit photographs the mount surface to which the light is emitted to output a photograph signal. The inspector inspects the terminal in accordance with the photograph signal. The photographing unit has N (N is a positive integer) photographing elements. The photograph signal is outputted respectively only from M (M is a positive integer smaller than the N) photographing elements of the N photographing elements.

Abstract: A method and apparatus for remote monitoring of an analog meter is set out which employs a Hough Transform on the edge points of the meter scale to obtain the center of the scale. The graduation marks and the needle are detected from the intensity profile along various radii. Thereby, the meter reading can be flexibly adopted to different meter scales during an easy training process. The method can be modified for oblique reading of the scale.

Abstract: An optical displacement sensor takes in a plurality of images of a target object by projecting a slit beam of light and using a two-dimensional image taking element by changing the image taking conditions each time. Parameters defining these conditions affecting the brightness of the obtained image are varied. From each of these images including an image of a portion of the sectional contour line of the target object, a segmented image satisfying a specified maximum brightness condition is extracted and a synthesized image is generated by gathering such segmented images. The target object is inspected from such synthesized image.

Abstract: A machine vision system (1) has two laser sources (2, 3) to illuminate a solder deposit from both sides for comprehensive coverage without occlusion. The camera (4) has an FGPA (32) programmed to define a subset of the sensor array (20) as a region of interest to be processed for each laser source (2, 3). This reduces the amount of data transfer and processing required. The image line (31) is dynamically maintained in the region of interest by adjustement of camara Z position according to warp of the substrate (S).

Abstract: The invention is directed to an apparatus for measuring a workpiece and includes a coordinate measuring apparatus or a machine tool. The invention further relates to a method for measuring the workpiece using such an apparatus. The apparatus includes a control and evaluation unit (26) and at least one measuring sensor (6) which functions independently of the control and evaluation unit and which can be displaced by a mechanism (27) of the coordinate measuring device in the three coordinate directions (x, y, z) in relation to the workpiece. The apparatus includes timers which are provided both in the measuring sensor (6) and in the control and evaluation unit (28) in order to synchronize the measuring sensor (6) and the control and evaluation unit (28). The timers function independently from each other and are adjusted to a common starting time.

Abstract: A system for measuring dimensions of cuboid objects may be used to measure dimensions of boxes travelling on a conveyor. The system has a pair of digital cameras which obtain images of one or more lines projected by a projector on upper surfaces of the objects. The height of the upper surfaces can be determined by triangulation. Lengths and widths of the upper surfaces are measured by locating endpoints of the projected lines and fitting rectangles to the located endpoints. The system does not require rigid mounting of the projector relative to the cameras. A third camera may be used to determine speed and direction of the conveyor motion.

Abstract: A device for the medical treatment of the eye with laser radiation uses auxiliary radiation for determining the eye position. With the aid of the auxiliary radiation, pictures are taken by means of a solid state image camera for determining eye movements and for causing the laser treatment radiation to follow accordingly. Infrared radiation sources, which are arranged in a triangle above the eye to be treated, are used for the auxiliary radiation.

Abstract: The present invention relates to a method and an apparatus for determining a three dimensional image of the a moving object by means of reflecting means such as mirrors and a planar beam of light such as a laser light. As the object enters the light a two dimensional image of the object is captured, wherein the image comprises both the reflection of the beam of light from the object and also the reflection from the reflecting means. By transformation procedure a two dimensional image is transformed to a two dimensional object image and based on plurality of such images a three dimensional image is defined from which the volume can be calculated. This can be used to determine the weight distribution of the object, which is important for portioning.

Abstract: A measuring device useful for measuring mechanical properties of highly flexible or limp sheet materials. The device includes a base, a pair of clamping members, with one of the clamping members being movable away from and toward the second clamping member. A load sensor is mounted in one of the clamping means for measurement of the required mechanical properties.

Abstract: A method for improving the accuracy of measurements made in non-contact gauging an object utilizing a detector to observe a laser line projected onto a surface of the object. A combination of detector lens f-number adjustments, surface scatter statistics, and laser coherence control are utilized to reduce speckle noise in the structured light gauge measurement system without the use of moving mechanical parts. This eliminates added mechanical motion errors and maximizes detectable laser light.

Abstract: A system for measuring unevenness formed by grooves and/or long waves in a surface of an object by using a measuring platform. The system moves the object and the measuring platform relative to each other and projects from the measuring platform a light streak that extends in a direction of the movement onto a surface of the object at a fixed projection angle that is tilted relative to a surface normal of the surface. The light streak is reproduced on a planar, position-sensitive photo receiver with a plurality of successive instantaneous exposures of the photo receiver, where the photo receiver is fixedly arranged on the measuring platform with a recording angle that is tilted relative to the fixed projection angle. The system records the surface along the direction of the movement with a plurality of continuous light-streak images and determines a surface profile of the surface along the direction of the movement from deformations in the plurality of the light-streak images.

Abstract: This invention is related to a three-dimensional measuring device for measuring three-dimensional positions of an objects. The three-dimensional measuring device comprises an optical projection system and an optical reception system. In a preliminary measurement prior to an actual measurement, the optical projection system projects slit light beam on the object with varying projection angle with in a narrow range, and the optical reception system receives the slit light beam reflected by the object and generates image signals corresponding to an amount of the received light synchronously with variation of the projection angle. Measurement conditions including intensity of the light beam and the projection angle for the actual measurement are set in accordance with the image signals of the actual measurement. Under the measurement conditions, the actual measurement is executed by projection the light beam on the object with varying the projection angle within a wide range.

Abstract: The invention concerns a device (8) for measuring the width (b) of a gap (2) between two structural parts (3), wherein the gap (2) is delimited by edges (17) of the structural parts (3). The device comprises an illumination component (9) for illuminating the structural parts (3), a detection component (10) for detecting reflections caused by the illumination component (9) on the structural parts (3) in the area of the gap (2), and an evaluation component (19) for evaluating the detected reflections and for determining the width (b) of the gap (2). To measure the width (b) of the gap (2) in a simple, reliable, accurate, and reproducible fashion independently of the surface finish of the structural parts (3), the illumination component (9) and the detection component (10) are arranged and oriented relative to one another and relative to the gap (2) such that the detection component (9) detects line-shaped reflections at the edges (17) of the structural parts (3) delimiting the gap (2).

Abstract: The present invention provides a three-dimensional measuring apparatus comprising a light projector for projecting light to an object, a light receiving element, a light receiving optical system for leading light projected on and then reflected by the object to the light receiving element, and a calculator for obtaining measured data for three-dimensional shape measurement based on signals output from the light receiving element. The light receiving optical system includes a first optical filter which transmits only light having substantially the same range of wavelengths as that of the light projected from the light projector, at least one second optical filter which transmits light having a different range of wavelengths as that of the first optical filter and a filter selector which selectively locates one of the first optical filter or the second filter or filters at an optical path of the light receiving optical system.