Measurement equipment

Abstract

To provide a high-speed and highly accurate measurement device.SOLUTION: A measurement device 100 measures a distance to an object. The measurement device includes: a light source 110 for projecting light; a mirror 129; a beam splitter 121 for dividing the light projected from the light source into measurement light to be guided to the object and reference light to be guided to the mirror; an event base camera 130 for acquiring data by detecting a change of a luminance value of the received light based on an interference waveform between the reference light reflected against the mirror and the measurement light reflected against the object; a processing section 140 for measuring distance to the object based on data of the interference waveform; and control means for performing control to change a light reception amount to be acquired by the event base camera.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a measurement device. [Background technology]

[0002] In recent years, there has been a demand for high precision in the alignment of components in applications such as multi-layer stacking of semiconductor chips, the assembly of rotary actuators for hard disk drives, the assembly of camera modules built into smartphones, and LED light distribution control.

[0003] Measuring apparatuses that use optical systems are known as apparatuses for measuring and inspecting objects including these components.

[0004] Patent Document 1 discloses a technique related to an interference-type shape measuring device, which identifies an interference pattern of the amount of received light that changes depending on the difference between the optical path length of the measurement light and the optical path length of the reference light, and acquires the surface shape of the measurement object based on the interference pattern. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-63153 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the shape measuring device disclosed in Patent Document 1 has a problem in that it cannot perform high-speed measurement because it needs to move around and measure a plurality of points and acquire and process a huge amount of data.

[0007] SUMMARY OF THE PRESENT EMBODIMENTS An object of the present invention is to provide a high-speed, high-precision measuring device. [Means for solving the problem]

[0008] A measurement device according to one embodiment of the present invention is a measurement device that measures the distance to an object, and includes a light source that projects light, a mirror, a beam splitter that splits the light projected from the light source into measurement light that is guided to the object and reference light that is guided to the mirror, an event-based camera that detects changes in the received brightness value of the interference waveform between the reference light reflected by the mirror and the measurement light reflected by the object to acquire data, a processing unit that measures the distance to the object based on the interference waveform data, and a control means that controls the event-based camera to change the amount of received light it acquires.

[0009] According to this aspect, the event-based camera detects a change in the received luminance value for the interference waveform between the reference light reflected by the mirror and the measurement light reflected by the object at each of the arranged pixels, and acquires data of the interference waveform portion at the timing of the detection, so that it is possible to reduce the amount of acquired data while acquiring data necessary for measuring the distance to the object. In other words, the measurement device can measure the object at high speed and with high accuracy.

[0010] In the above aspect, the control unit may include a driver that drives the mirror so as to change the optical path length difference between the measurement light and the reference light.

[0011] According to this aspect, the measurement apparatus can measure an object at high speed and with high accuracy using a white light interferometry measurement method.

[0012] In the above aspect, the control means may use a wavelength swept light source as the light source so that the wavelength of the light projected from the light source changes continuously.

[0013] According to this aspect, the measurement device can measure the object at high speed and with high accuracy using a wavelength sweeping measurement method.

[0014] The above aspect may include a log amplifier that uses an increase or decrease in the amount of received light acquired by the event-based camera as polarity data and calculates the amount of received light acquired by the event-based camera based on an accumulation of the polarity data.

[0015] According to this aspect, the logarithmic amplifier uses the increase or decrease in the amount of received light acquired by the event-based camera as polarity data and can quickly capture minute changes, thereby reducing the imaging time.

[0016] In the above aspect, the event-based camera may further include an adjustment unit capable of adjusting an amount of data to be processed.

[0017] According to this aspect, the adjustment unit adjusts the amount of data processed by the event-based camera, so that even if events occur simultaneously in multiple pixels, the event-based camera can perform appropriate processing.

[0018] In the above aspect, the adjustment unit may have an ROI function for reading out data of a predetermined partial region.

[0019] According to this aspect, the region required for measuring the object is set as the region from which data is read using the ROI function, so that the object can be measured more appropriately.

[0020] In the above aspect, the adjustment unit may include a light reduction unit configured to guide light irradiated onto a predetermined partial area to the event-based camera and to not guide light irradiated onto other areas to the event-based camera.

[0021] According to this aspect, a light reduction unit is arranged so as to guide light irradiated to a specified area to the event-based camera and not guide light irradiated to other areas to the event-based camera, thereby making it possible to more appropriately measure the area of ​​the object that is necessary for measurement.

[0022] In the above aspect, the light reducing portion may be formed of a liquid crystal panel.

[0023] According to this aspect, a liquid crystal panel can be used to form a shading section that includes a transmissive region that transmits light irradiated to a specified area, and a shading region that blocks light in other areas.

[0024] In the above aspect, the light reducing unit may be disposed on a common optical path of the measurement light and the reference light.

[0025] According to this aspect, the optical paths of the measurement light and the reference light are under the same conditions, so that it is possible to reduce the possibility of affecting the interference accuracy.

[0026] In the above aspect, the predetermined partial area may be set in advance according to the shape of the object.

[0027] According to this aspect, depending on the shape of the object, the area that is the characteristic part of the object and the area to be measured are set as a specified partial area from which data is read or through which light is transmitted, so that the object can be measured more appropriately. Effect of the Invention

[0028] According to the present invention, a high-speed and high-precision measuring device can be provided. [Brief description of the drawings]

[0029] [Figure 1] 1 is a schematic diagram showing a configuration of a measurement apparatus 100 according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a schematic diagram showing how data is acquired by an event-based camera 130 used as an image capture element. [Diagram 3] FIG. 1 is a diagram showing how the surface shape of an object (distance to the surface) is measured by measurement device 100 that uses event-based camera 130 as an imaging element. [Figure 4] FIG. 13 is a diagram showing changes (increases and decreases) in the amount of received light acquired by the event-based camera 130 as two polarities, and illustrating an envelope curve based on the accumulation of the two polarity data. [Diagram 5]FIG. 13 is a diagram showing an example in which a ROI (Region Of Interest) function is used as an adjustment unit capable of adjusting the amount of data processed by the event-based camera 130. [Figure 6] FIG. 13 is a diagram showing an example of teaching an area from which data is read using the event-based camera 130. [Figure 7] 13A and 13B are diagrams illustrating an example of teaching an area from which data is read out by referring to drawing information. [Figure 8] FIG. 13 is a diagram showing an example in which a light blocking unit is used as an adjustment unit capable of adjusting the amount of data processed by the event-based camera 130. [Figure 9] 2 is a schematic diagram showing a configuration in which a light blocking portion is arranged in the measurement device 100 shown in FIG. 1. FIG. [Figure 10] 1 is a schematic diagram showing the configuration and functions of a measuring device 100A to which the measuring device 100 according to the first embodiment of the present invention is applied. [Figure 11] FIG. 1 is a schematic diagram showing the configuration of a measurement apparatus 200 according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the embodiment described below is merely a specific example for carrying out the present invention, and is not intended to limit the interpretation of the present invention. In addition, in order to facilitate understanding of the description, the same reference numerals are used as far as possible for the same components in each drawing, and duplicated descriptions may be omitted.

[0031] First Embodiment [Measurement equipment configuration] Fig. 1 is a schematic diagram showing the configuration of a measurement device 100 according to a first embodiment of the present invention. As shown in Fig. 1, the measurement device 100 includes a light source 110, an optical system 120, an event-based camera 130, and a processing unit 140. The optical system 120 includes a beam splitter 121, a plurality of lenses 122-126, and a plurality of mirrors 127-129. Furthermore, the measurement device 100 includes a driving unit 150 (control means) that drives the mirror 129.

[0032] The light source 110 projects light L0. The light source 110 is typically a white light source, and may be, for example, an SLD (super luminescent diode) light source. The SLD light source is a broadband light source having the characteristics of both a light emitting diode (LED) and a semiconductor laser (LD), and has higher coherence than an LED light source but lower coherence than a laser light. The light source 110 emits light with a constant intensity, and the emission intensity does not change.

[0033] Furthermore, the light source 110 may also be, for example, a halogen lamp, a white LED, or a white laser light source.

[0034] Light L0 projected from the light source 110 passes through a lens 122 (for example, a collimator lens) to be collimated, and is reflected by a mirror 127. The light L0 reflected by the mirror 127 then passes through a lens 123 to be condensed, and enters the beam splitter 121.

[0035] The beam splitter 121 splits the light L0 into a measurement light L1 to be guided to the object T and a reference light to be guided to the mirror 129. In other words, a part of the light L0 is reflected by the beam splitter 121 (measurement light L1), and the remaining part of the light L0 is transmitted through the beam splitter 121 (reference light L2).

[0036] In the lens 124 (e.g., an objective lens), the measurement light L1 is collimated by passing through the lens 124. Thereafter, the measurement light L1 is irradiated onto an area of ​​the object T, and a portion of the measurement light L1 reflected by the object T is condensed by passing through the lens 124 and enters the beam splitter 121 again.

[0037] On the other hand, the reference light L2 transmitted through the beam splitter 121 is collimated by transmitting through a lens 125, reflected by a mirror 128, and irradiated onto a mirror 129. The mirror 129 is a so-called reference mirror.

[0038] The reference light L2 reflected by the mirror 129 is then reflected by the mirror 128, and while being condensed by transmitting through the lens 125, enters the beam splitter 121 again.

[0039] Measurement light L1 reflected by object T and incident on beam splitter 121 and reference light L2 reflected by mirror 129 and incident on beam splitter 121 interfere with each other, are collimated as interference light L3 through lens 126, and are guided to event-based camera 130. Event-based camera 130 detects changes in the luminance value of the interference waveform L3 received to acquire data. The data acquired by event-based camera 130 will be described later.

[0040] The processing unit 140 measures the distance to the object T based on the data of the interference waveform L3 acquired by the event-based camera 130 and the position of the mirror 129 (the optical path length of the reference light L2) controlled by the driving unit 150 described later.

[0041] The driving unit 150 (control means) is, for example, an actuator constituted by a voice coil motor (VCM) or the like, and moves the mirror 129 along the optical axis direction so as to change the optical path length of the reference light L2.

[0042] In this way, the optical path length of the reference light L2 is changed to change the optical path length difference between the measurement light L1 and the reference light L2, thereby generating an interference waveform. Specifically, an interference fringe can be observed around the position where the phase difference is 0, and an interference waveform is generated when the optical path lengths of the measurement light L1 and the reference light L2 match. A method of measuring an object using the interference waveform is, for example, a measurement method called white light interferometry.

[0043] [About event-based cameras] Here, we will explain the event-based camera 130 used as an imaging element. The event-based camera 130 detects changes in the luminance value of received light in each of the arranged pixels, captures an interference waveform in the part (pixel) where the change is detected at the detection timing, and obtains data on the polarity, time, and coordinates of the luminance change.

[0044] Fig. 2 is a schematic diagram showing how data is acquired by an event-based camera 130 used as an image sensor. As shown in Fig. 2, the event-based camera 130 detects a change in the luminance value of received light at each of the arranged pixels, acquires data on the interference waveform portion required for measurement at the timing of the detection, and does not acquire data on other portions.

[0045] Conventionally, CMOS used as an imaging element acquires all data for each pixel, and the amount of data is enormous. In other words, compared to a CMOS imaging element, the event-based camera 130 acquires data of the interference waveform portion necessary for measuring the distance to the target T more efficiently.

[0046] As described above, the event-based camera 130 is used as an imaging element to detect changes in the brightness value of received light at each of the arrayed pixels, and data on the interference waveform portion is acquired at the timing of the detection, thereby making it possible to reduce the amount of data acquired while acquiring the data necessary to measure the distance to the target object T.

[0047] 3 is a diagram showing how the surface shape (distance to the surface) of an object is measured by measuring device 100 using event-based camera 130 as an imaging element. As shown in Fig. 3, for measuring die bonding and the camera module, event-based camera 130 acquires data required for measurement at multiple points (all at once on the surface) and processes (reads, etc.) the required data efficiently and quickly. As a result, measuring device 100 can measure the object quickly and with high accuracy.

[0048] Furthermore, the event-based camera 130 may include a logarithmic amplifier that detects changes in the brightness value of the received light at each of the arrayed pixels and acquires data of the interference waveform portion at the timing of the detection, thereby capturing minute changes in the amount of received light.

[0049] 4 shows changes (increases and decreases) in the amount of received light acquired by the event-based camera 130 as bipolarity, and is a diagram showing an envelope based on the accumulation of the bipolar data. As shown in Fig. 4, the log amplifier captures minute changes in the amount of received light acquired by the event-based camera 130, and the increase and decrease of the changes are treated as bipolar data. Then, based on the accumulation of the bipolar data, the envelope of the distribution of the amount of received light is specified and calculated as the amount of received light acquired by the event-based camera 130.

[0050] In this way, by including a logarithmic amplifier in event-based camera 130, minute changes in the amount of received light acquired by event-based camera 130 can be captured at high speed, thereby shortening the imaging time.

[0051] As described above, the event-based camera 130 detects the occurrence of an event, which is a change in the amount of received light (brightness value), at each of the arranged pixels. The event-based camera 130 then acquires data of the interference waveform portion at the pixel where the event has been detected. Here, even if events occur simultaneously at multiple pixels, an adjustment unit capable of adjusting the amount of data to be processed according to the capacity, performance, etc. of the event-based camera 130 may be provided so that the data can be appropriately processed.

[0052] [About the ROI function] Fig. 5 is a diagram showing an example in which a ROI (Region Of Interest) function is used as an adjustment unit capable of adjusting the amount of data processed by the event-based camera 130. As shown in Fig. 5, five rectangular regions 0 to 4 from which data is read are set in the maximum effective imaging region, which is the region capable of imaging as the event-based camera 130, and data is set not to be read from the other regions.

[0053] As a result, the event-based camera 130 detects changes in the luminance value of received light (occurrence of an event) in pixels arranged in rectangular regions 0 to 4 and acquires data, but does not acquire data in other regions regardless of whether an event has occurred. The event-based camera 130 does not need to monitor the occurrence of an event in the other regions.

[0054] Note that, here, as an example, five rectangular areas 0 to 4 are set as areas from which data is read out, but this is not limited to this, and for example, four or less rectangular areas, or six or more rectangular areas may be set.

[0055] Furthermore, the size and shape of each rectangular area from which data is read may be the same or different, and may be a shape other than rectangular.

[0056] The area from which data is read (e.g., number, shape, position, etc.) may be set appropriately depending on the type, capacity, and performance of the event-based camera 130, and the type and shape of the object to be measured, but the setting may be set in advance by the user or by teaching.

[0057] 6 is a diagram showing an example of teaching an area from which data is read using the event-based camera 130. For example, an area from which data is read using the event-based camera 130 is taught so that the measurement device 100 measures the target object T.

[0058] As shown in FIG. 6, the event-based camera 130 acquires data for all pixels in the maximum effective imaging area using the above-mentioned white light interference measurement method. The event-based camera 130 may not be able to acquire data simultaneously for all pixels depending on, for example, the type, capacity, and performance, so it acquires data sequentially for each number of pixels that can be acquired simultaneously. Note that since the purpose here is to teach the area from which data is read out, if detailed data is not required as data acquired by the event-based camera 130, it is not necessary to target all pixels. For example, the data acquired by the event-based camera 130 may be acquired in a thinned manner, targeting every few pixels.

[0059] Then, 3D data of the object T is generated based on the data acquired by the event-based camera 130, and the area from which data is read is set by referring to the 3D data. The area from which data is read may be set by the user, for example, an area that is a characteristic part of the object T and an area to be measured, or may be automatically set for an area having a predetermined height.

[0060] Note that, here, data was acquired for all pixels in the maximum effective imaging area by the event-based camera 130 while using the above-described white light interference measurement method, but a CMOS may also be used as the imaging element in this teaching.

[0061] For example, a half mirror or the like may be disposed so that the interference waveform L3 described with reference to Fig. 1 can be received by a CMOS imaging element disposed separately from the event-based camera 130. As a result, during teaching, the interference waveform L3 reflected by the half mirror is received by the CMOS imaging element.

[0062] Then, by using the above-mentioned white light interference measurement method and acquiring data for all pixels in the maximum effective imaging area using the CMOS imaging element, 3D data of the object T is generated, as explained using Figure 6, and the area from which data is to be read is set by referring to the 3D data.

[0063] Furthermore, as a method for setting the area from which data is read out by teaching, for example, drawing information such as CAD data of the target object T is imported and the area from which data is read out is set by referring to the drawing information.

[0064] Fig. 7 is a diagram showing an example of teaching an area from which data is read out by referring to drawing information. As shown in Fig. 7, CAD data of the object T to be measured by the measuring device 100 is imported as drawing information, and the area from which data is read out is set by referring to the imported drawing information. The area from which data is read out may be, for example, an area that is a characteristic part of the object T and an area to be measured, set by the user, or may be automatically set for an area having a predetermined height.

[0065] It is also possible to generate a distance image (image data in which the pixel value is the height) and set the area from which the data is read by referring to the distance image. This has the effect of reducing the calculation cost of the display process compared to handling it as coordinate data in 3D space.

[0066] In addition, a rendering process (generating a pseudo image by optical simulation) based on 3D data may be performed to generate a grayscale image, and the area may be set by referring to the grayscale image. This has the effect of reducing the calculation cost of the display process.

[0067] [About the light-shielding part] Fig. 8 is a diagram showing an example in which a light blocking unit is used as an adjustment unit capable of adjusting the amount of data processed by event-based camera 130. As shown in Fig. 8, a light blocking unit including a region that transmits light and a region that blocks light is disposed in the optical path of light (L0, L1, L2) projected from light source 110 in optical system 120. As shown in Fig. 8, when light is irradiated onto the light irradiation region, four transmission regions that are regions through which the light passes are set, and light blocking regions are set in other regions so that the light is blocked.

[0068] As a result, event-based camera 130 receives light that has passed through the transparent region, and therefore detects a change in the received luminance value (occurrence of an event) for pixels arranged corresponding to the transparent region among the multiple pixels arranged in event-based camera 130, and acquires data. On the other hand, event-based camera 130 does not receive light blocked by a light-shielding region, and therefore it is not necessary to monitor the presence or absence of an event for pixels arranged corresponding to the light-shielding region among the multiple pixels arranged in event-based camera 130.

[0069] Note that, here, four circular transparent regions are set as light transmitting regions, but this is not limited to this, and for example, three or less, or five or more, transparent regions may be set.

[0070] Furthermore, the size and shape of each transparent area may be the same or different, may be other than circular (e.g., elliptical, oblong, rectangular, etc.), and may be set appropriately depending on the shape of the object to be measured.

[0071] The transparent areas (e.g., number, shape, position, etc.) may be set appropriately depending on the type, capacity, and performance of the event-based camera 130, and the type and shape of the object to be measured, but the settings may be set in advance by the user or may be set by teaching.

[0072] For setting the transmission area, the above-mentioned data read area teaching method can be applied. For example, for the data read area shown in Figures 6 and 7, the light-shielding part may be set such that the area corresponding to the data read area is set as the transmission area, and the other areas are set as the light-shielding area.

[0073] Furthermore, the light-shielding portion having such a transmissive region and a light-shielding region may be realized by using, for example, a liquid crystal panel.

[0074] Here, the liquid crystal panel is composed of a polarizing filter (vertical), a glass substrate (individual electrodes), liquid crystal sandwiched between alignment layers, a glass substrate (common electrode), and a polarizing filter (horizontal), and light that has been linearly polarized by the polarizing filter cannot pass through the polarizing filter (horizontal) while maintaining its polarization direction (light-shielding state). On the other hand, when the polarization direction of the light is bent 90 degrees by the liquid crystal sandwiched between the alignment layers, it can pass through the polarizing filter (horizontal) (light-non-shielding state). The electrodes on the glass substrate (individual electrodes) and the glass substrate (common electrode) are provided to switch between a light-shielding state and a non-light-shielding state for the liquid crystal.

[0075] Fig. 9 is a schematic diagram showing a configuration in which a light blocking unit is arranged in the measurement device 100 shown in Fig. 1. As shown in Fig. 9, a light blocking unit 160 is arranged between the lens 122 and the mirror 127.

[0076] The position where the light-shielding portion 160 is arranged is not limited to between the lens 122 and the mirror 127, but may be, for example, between the light source 110 and the lens 122, between the mirror 127 and the lens 123, between the lens 123 and the beam splitter 121, between the beam splitter 121 and the lens 126, between the lens 126 and the event-based camera 130, etc., or may be on a common optical path of the measurement light L1 and the reference light L2 in the optical system 120 (on the optical path of the lights L0 and L3).

[0077] By placing the light-shielding portion 160, there is a possibility that the irradiated light will be polarized and diffracted by the liquid crystal, causing a change in its state. However, if the measurement light L1 and the reference light L2 are on a common optical path, the optical paths of the measurement light L1 and the reference light L2 will be under the same conditions, thereby reducing the possibility of affecting the interference accuracy.

[0078] Here, an LCD panel has been used as an example of a light-shielding section having a transparent region and a light-shielding region, but in order to guide light irradiated to a specific region to the event-based camera 130 and prevent light irradiated to other regions from reaching the event-based camera 130, a DMD (digital micromirror device) may also be used.

[0079] For example, a DMD is used for mirror 127 constituting measurement device 100 shown in Fig. 1. The DMD reflects light irradiated to a predetermined partial area and absorbs light irradiated to other areas. In other words, the light irradiated to a predetermined partial area is reflected and made to enter mirror 123, and is ultimately guided to event-based camera 130.

[0080] In this way, the liquid crystal panel, DMD, etc. guide the light irradiated to a predetermined partial area to the event-based camera 130, and block or absorb the light irradiated to other areas, thereby reducing the light from being guided to the event-based camera 130. In other words, they can be said to be a light reduction unit that reduces a portion of the irradiated light.

[0081] As described above, the measuring device 100 according to the first embodiment of the present invention uses the event-based camera 130 as an image sensor, and furthermore, a logarithmic amplifier appropriately captures minute changes in the amount of received light, and the ROI function and the light blocking unit 160 appropriately adjust the amount of data processed by the event-based camera 130. As a result, the measuring device 100 can more appropriately measure the object T at high speed and with high accuracy.

[0082] 1 and 9, the optical system 120 is composed of the beam splitter 121, the plurality of lenses 122-126, and the plurality of mirrors 127-129, but is not limited thereto. For example, any optical system may be configured as long as it can split the light L0 projected by the light source 110 into the measurement light L1 and the reference light L2, and finally receive the interference light between the measurement light L1 and the reference light L2 reflected by the object and the mirror with the event-based camera 130, thereby enabling a measurement method using the white light interference method.

[0083] In the present embodiment, the ROI function and the shading unit 160 are taken as examples of adjustment units capable of adjusting the amount of data processed by the event-based camera 130, and the teaching of the data read area, the transparent area, the shading area, etc. is described, but the present invention is not limited to this. For example, the number of pixels in the event-based camera 130 may be reduced (reduced resolution) so that data can be acquired even if an event occurs simultaneously in all pixels.

[0084] [Application example] Fig. 10 is a schematic diagram showing the configuration and functions of a measurement apparatus 100A to which the measurement apparatus 100 according to the first embodiment of the present invention is applied. As shown in Fig. 10, the measurement apparatus 100A includes a light source 110, an optical system 120A, an event-based camera 130, and a CMOS image sensor 170. Although shown in Fig. 10 as a schematic, the measurement apparatus 100A differs from the measurement apparatus 100 shown in Fig. 1 in that a CMOS image sensor 170 and a half mirror 171A are added.

[0085] The measurement apparatus 100A basically measures the object T by a white light interferometry measurement method, as described in the measurement apparatus 100. The event-based camera 130 functions as an image sensor that acquires data on the object T in the Z-axis direction, as described in the measurement apparatus 100.

[0086] Furthermore, in the measurement device 100A, the CMOS imaging element 170 receives light reflected by the half mirror 171A and acquires image data of the object T. More specifically, the CMOS imaging element 170 functions as an imaging element that acquires an image of the object T by measurement on the XY axis plane.

[0087] As described above, according to the measurement device 100A, by combining the image acquired by the CMOS image sensor 170 with a white light interferometry measurement method using the event-based camera 130, it is possible to realize measurement of the object T in the XYZ coordinate axes using a single sensor.

[0088] The same role as the CMOS image sensor 170 may be achieved by using the event-based camera 130. The event-based camera 130 detects luminance changes, but there are types that output not only the polarity of the luminance change but also the amount of luminance change. In this case, it is possible to restore the luminance information by performing integration processing.

[0089] Furthermore, the above-mentioned ROI function and the light reduction unit may be used in combination. A screen may be divided into a plurality of ROI regions, which may be sequentially switched and captured, and then the images may be synthesized to form a single image.

[0090] In this way, if the same role as that of the CMOS image sensor 170 is realized using the event-based camera 130, there is no need to provide a new CMOS image sensor 170, and the structure can be simplified.

[0091] It should be noted that the log amplifier, ROI function, light blocking unit 160, and the like, which are applied to measurement apparatus 100, can also be applied to measurement apparatus 100A.

[0092] <Second embodiment> Next, in a second embodiment of the present invention, a measurement device using a wavelength swept light source as a control means for controlling so as to change the amount of received light acquired by an event-based camera will be described. Note that in this embodiment, mainly, configurations different from the first embodiment of the present invention will be described in detail, and descriptions of matters common to the first embodiment will be omitted or simplified.

[0093] Fig. 11 is a schematic diagram showing the configuration of a measurement apparatus 200 according to the second embodiment of the present invention. As shown in Fig. 11, the measurement apparatus 200 includes a light source 210, an optical system 120, an event-based camera 130, and a processing unit 140. The optical system 120 includes a beam splitter 121, a plurality of lenses 122-126, and a plurality of mirrors 127-129.

[0094] The measuring device 100 according to the first embodiment of the present invention shown in FIG. 1 is provided with a driving unit 150 that drives a mirror 129 as a control means for controlling the amount of received light acquired by the event-based camera 130 to change, and an interference waveform is generated by changing the optical path length difference between the measurement light L1 and the reference light L2, thereby measuring the object T using a white light interferometry measurement method.

[0095] In the measuring device 200 of this embodiment, a wavelength swept light source is used as the light source 210 as a control means for controlling the amount of received light acquired by the event-based camera 130 to change, and an interference waveform between the measurement light L1 and the reference light L2 is generated by continuously changing the wavelength of the light emitted from the light source 210, and the object T is measured by a measurement method called the wavelength swept method.

[0096] The light source 210 may be, for example, a MEMS-VCSEL (Micro Electro Mechanical Systems-Vertical Cavity Surface Emitting Laser), a DFB (Distributed Feedback) laser, or a SSG-DBR (Super Structure Grating-Distributed Bragg reflector) laser as a wavelength swept light source. Note that the light source 210 emits light at a constant intensity, and the emission intensity does not change, similar to the light source 110 of the measuring device 100 according to the first embodiment.

[0097] MEMS-VCSEL changes the laser oscillation wavelength (wavelength sweep) by driving the resonator mirror with MEMS, DFB laser sweeps the wavelength by changing the drive current of the laser diode, and SSG-DBR has a diffraction grating called a distributed reflector formed on the two resonator mirrors and sweeps the wavelength by injecting current.

[0098] The event-based camera 130 detects changes in the brightness value of the received interference waveform L3 between the measurement light L1 and the reference light L2, which is generated by varying the wavelength of the light projected from the light source 210, and acquires data, in a manner similar to that described in the first embodiment of the present invention.

[0099] The processing unit 140 measures the distance to the target object T based on the data of the interference waveform L3 acquired by the event-based camera 130, the wavelength (frequency) of the light projected from the light source 210, and the like.

[0100] As described above, according to the measuring device 200 of the second embodiment of the present invention, when measuring the object T by a wavelength sweeping measurement method using a wavelength swept light source as the light source 210, the event-based camera 130 is used as the image sensor to detect changes in the luminance value of the light received at each arranged pixel, and data of the interference waveform portion is acquired at the timing of the detection, so that it is possible to reduce the amount of data acquired while acquiring the data necessary for measuring the distance to the object T.

[0101] It should be noted that the measurement apparatus 200 according to this embodiment can also apply the log amplifier, ROI function, light blocking unit 160, and the like, which are applied to the measurement apparatus 100 according to the first embodiment of the present invention.

[0102] Furthermore, as in the measuring device 100A described using FIG. 10, by adding a CMOS image sensor 170 or the like to the measuring device 200 according to this embodiment, it is possible to combine the image acquired by the CMOS image sensor 170 with a wavelength sweeping measurement method using the event-based camera 130, thereby realizing measurement of the object T in the XYZ coordinate axes with a single sensor.

[0103] The above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to limit the present invention. The elements of the embodiments, as well as their arrangements, materials, conditions, shapes, sizes, etc., are not limited to those shown as examples and can be changed as appropriate. In addition, configurations shown in different embodiments can be partially substituted or combined with each other.

[0104] [Appendix] A measuring device (100, 200) for measuring a distance to an object, A light source (110, 210) that projects light; Miller (129) and a beam splitter (121) that splits the light emitted from the light source into a measurement light to be guided to the object and a reference light to be guided to the mirror; an event-based camera (130) that detects a change in a luminance value of the received light with respect to an interference waveform between the reference light reflected by the mirror and the measurement light reflected by the object, and acquires data; A processing unit (140) that measures a distance to the object based on data of the interference waveform; A control means (150, 210) for controlling the event-based camera to change the amount of received light; A measuring device (100, 200) comprising: [Explanation of symbols]

[0105] 100, 100A, 200... measuring device, 110, 210... light source, 120, 120A... optical system, 121... beam splitter, 122 to 126... lenses, 127 to 129... mirror, 130... event-based camera, 140... processing unit, 150... driving unit, 160... light shielding unit, 170... CMOS image sensor, 171A... half mirror, L0 to L3... light, T... object

Claims

1. A measuring device for measuring a distance to an object, A light source that projects light; Miller and a beam splitter that splits the light emitted from the light source into a measurement light that is guided to the object and a reference light that is guided to the mirror; an event-based camera that detects a change in a luminance value of a received light with respect to an interference waveform between the reference light reflected by the mirror and the measurement light reflected by the object, and acquires data; A processing unit that measures a distance to the object based on data of the interference waveform; A control means for controlling the event-based camera to change an amount of received light; A measuring device comprising:

2. the control unit includes a drive unit that drives the mirror so as to change the optical path length difference between the measurement light and the reference light. The measurement device according to claim 1 .

3. the control means uses a wavelength swept light source as the light source so that the wavelength of the light emitted from the light source is continuously changed; The measuring device according to claim 1 or 2.

4. a logarithmic amplifier that uses an increase or decrease in the amount of received light acquired by the event-based camera as polarity data and calculates the amount of received light acquired by the event-based camera based on an accumulation of the polarity data; The measuring device according to claim 1 .

5. An adjustment unit capable of adjusting an amount of data processed by the event-based camera is further provided. The measuring device according to claim 1 .

6. The adjustment unit has an ROI function for reading data of a predetermined partial area. The measurement device according to claim 5.

7. The adjustment unit includes a light reduction unit configured to guide light irradiated onto a predetermined partial area to the event-based camera and not guide light irradiated onto other areas to the event-based camera. The measuring device according to claim 5 or 6.

8. The light reducing unit is composed of a liquid crystal panel. The measurement device according to claim 7.

9. The light reducing unit is disposed on a common optical path of the measurement light and the reference light. The measuring device according to claim 7 or 8.

10. The predetermined partial area is set in advance according to the shape of the object. The measuring device according to any one of claims 6 to 9.

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