阅读说明：本技术 光学测量装置以及光学测量方法 (Optical measuring device and optical measuring method ) 是由 髙嶋润 金谷义宏 于 2019-10-21 设计创作，主要内容包括：本发明自受光量分布信号获得测定波形信号。光学测量装置100包括：光源10,向对象物TA发出光；受光部40,以多个像素各自可检测受光量的方式构成,且获得每个像素的受光量分布信号；获取部51,基于不存在对象物TA时的受光量分布信号,自利用对象物TA所反射的反射光的受光量分布信号获取测量波形信号MS；以及调整部53,在反射光的受光量分布信号的一部分受光量为规定值以上时,以获取测量波形信号MS的方式,调整对于反射光的受光量分布信号的感度参数。(The present invention obtains a measurement waveform signal from a light receiving amount distribution signal. The optical measurement apparatus 100 includes: a light source 10 that emits light toward an object TA; a light receiving unit 40 configured to detect the amount of light received by each of the plurality of pixels and obtain a light receiving amount distribution signal for each pixel; an acquisition unit 51 that acquires a measurement waveform signal MS from a light-receiving amount distribution signal of reflected light reflected by the object TA based on the light-receiving amount distribution signal when the object TA is not present; and an adjusting unit 53 that adjusts a sensitivity parameter of the light receiving amount distribution signal with respect to the reflected light so as to acquire the measurement waveform signal MS when a part of the light receiving amount distribution signal of the reflected light is equal to or greater than a predetermined value.)

1. An optical measuring device, comprising:

a light projecting section for emitting light to an object;

a light receiving unit configured to obtain a light receiving amount distribution signal for each of a plurality of pixels, the light receiving unit being configured such that each of the plurality of pixels can detect a light receiving amount;

an acquisition unit that acquires a measurement waveform signal from the light receiving amount distribution signal of reflected light reflected by the object, based on the light receiving amount distribution signal when the object is not present; and

and an adjusting unit configured to adjust a sensitivity parameter of the light receiving amount distribution signal with respect to the reflected light so as to acquire the measurement waveform signal when a part of the light receiving amount distribution signal of the reflected light is equal to or greater than a predetermined value.

2. Optical measuring device according to claim 1,

the adjustment unit adjusts a sensitivity parameter of the light receiving amount distribution signal with respect to the reflected light so that a peak light receiving amount of the acquired measurement waveform signal becomes a predetermined value or more.

3. Optical measuring device according to claim 1 or 2,

the adjustment unit sets a range for adjusting the sensitivity parameter based on the reflectance of the object.

4. Optical measuring device according to claim 1 or 2,

the adjustment unit sets a range for adjusting the sensitivity parameter based on the sensitivity parameter at the time of acquiring the previous measurement waveform signal.

5. Optical measuring device according to one of claims 1 to 4,

the sensitivity parameter includes at least one of a light projection amount of the light, a light projection power of the light, an exposure time of the light receiving unit, and a gain of the light receiving unit.

6. Optical measuring device according to one of the claims 1 to 5,

the predetermined value of the light receiving amount is a value at which the light receiving amount is saturated.

7. The optical measurement device according to any one of claims 1 to 6, further comprising:

and a measuring unit that measures a distance from the optical measuring device to the object based on the measurement waveform signal.

8. The optical measurement device according to any one of claims 1 to 7, further comprising:

an optical system for irradiating the object with the light having a chromatic aberration along an optical axis direction and irradiating the object with the light having the chromatic aberration

The light contains a plurality of wavelength components,

the optical system condenses the reflected light,

the light receiving unit is configured to be capable of detecting the amount of light received for each of the wavelength components.

9. An optical measurement method, comprising:

a light projecting step of emitting light to an object;

a light reception step of obtaining a light reception amount distribution signal for each pixel;

an acquisition step of acquiring a measurement waveform signal from the light receiving amount distribution signal of reflected light reflected by the object based on the light receiving amount distribution signal when the object is not present; and

an adjustment step of adjusting a sensitivity parameter of the light receiving amount distribution signal with respect to the reflected light so as to acquire the measurement waveform signal when a part of the light receiving amount distribution signal of the reflected light is equal to or greater than a predetermined value.

10. The optical measuring method according to claim 9,

the adjusting step adjusts a sensitivity parameter of the light receiving amount distribution signal with respect to the reflected light so that a peak light receiving amount of the acquired measurement waveform signal becomes a predetermined value or more.

11. Optical measuring method according to claim 9 or 10,

the adjusting step comprises: setting a range for adjusting the sensitivity parameter based on the reflectance of the object.

12. Optical measuring method according to claim 9 or 10,

the adjusting step comprises: setting a range for adjusting the sensitivity parameter based on the sensitivity parameter when the measurement waveform signal was acquired last time.

13. The optical measuring method according to any one of claims 9 to 12,

the sensitivity parameter includes at least one of a light projection amount of the light, a light projection power of the light, an exposure time of a light receiving unit, and a gain of the light receiving unit.

14. The optical measuring method according to any one of claims 9 to 13,

the predetermined value of the light receiving amount is a value at which the light receiving amount is saturated.

15. The optical measuring method according to any one of claims 9 to 14, further comprising:

a measurement step of measuring a distance from an optical measurement device to the object based on the measurement waveform signal.

Technical Field

The present invention relates to an optical measuring apparatus and an optical measuring method.

Background

It is known that in a reflective optical sensor 1 including a light projecting section 101 and a light receiving section 102 configured to accumulate charges associated with light reception for a predetermined time by an arrangement of a plurality of photoelectric conversion elements and output the accumulated charges, based on the length of time allowed as a response time from the start of light projection onto the detection object to the execution of the determination output and the length of the cycle of the measurement process including the adjustment process of light projection and light reception and sensitivity, then, the maximum number of sensitivity adjustments that can be achieved within the response time is obtained, and a combination of adjustment ranges of the sensitivity parameters of the exposure time, the light projection intensity, and the light receiving amount magnification is set on the condition that a dynamic range (dynamic range) obtained by the maximum number of sensitivity adjustments does not exceed a maximum dynamic range determined by the maximum number and a maximum magnification adjusted by one sensitivity adjustment process (see patent document 1). The optical sensor can comply with the required response time and expand the dynamic range as much as possible.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-190378

Disclosure of Invention

Problems to be solved by the invention

On the other hand, when a plurality of pixels constituting the light receiving section are used to obtain a light receiving amount distribution signal for each pixel, it is known that the light receiving amount distribution signal includes a return light component reflected at a connection portion of an optical fiber cable (fiber cable) or the like in addition to a signal light component reflected by an object.

In order to remove the return light component, in a conventional optical measuring apparatus, a measurement waveform signal which is a signal light component reflected by an object is obtained by subtracting a light receiving amount distribution signal obtained in a state where the object is not present from a light receiving amount distribution signal obtained in a state where the object is present, and a distance to the object is measured based on the measurement waveform signal.

However, if the light receiving amount distribution signal is obtained in the state where the object is present by using the sensitivity parameter of the light receiving amount distribution signal obtained in the state where the object is not present, a part of the light receiving amount may be saturated, and the measurement waveform signal may not be obtained.

Therefore, an object of the present invention is to provide an optical measuring apparatus and an optical measuring method capable of obtaining a measurement waveform signal from a light receiving amount distribution signal.

Means for solving the problems

An optical measuring apparatus according to an embodiment of the present invention includes: a light projecting section for emitting light to an object; a light receiving unit configured such that each of the plurality of pixels can detect a light receiving amount, and configured to obtain a light receiving amount distribution signal for each pixel; an acquisition unit that acquires a measurement waveform signal from a light-receiving amount distribution signal of reflected light reflected by an object, based on a light-receiving amount distribution signal when the object is not present; and an adjusting unit that adjusts a sensitivity parameter of the light receiving amount distribution signal with respect to the reflected light so as to acquire the measurement waveform signal when a part of the light receiving amount distribution signal of the reflected light is equal to or greater than a predetermined value.

According to the above embodiment, when a part of the light receiving amount distribution signal of the reflected light reflected by the object is equal to or greater than the predetermined value, the sensitivity parameter of the light receiving amount distribution signal of the reflected light with respect to the object is adjusted so as to acquire the measurement waveform signal. In this way, the light receiving amount distribution signal of the reflected light of the object obtained after the sensitivity parameter is adjusted can include the signal light component in the light receiving amount distribution signal of the reflected light of the object obtained after the sensitivity parameter is adjusted, while the light receiving amount is made smaller than a predetermined value, for example, without saturating the light receiving amount. Therefore, by adjusting the sensitivity parameter of the light receiving amount distribution signal of the reflected light reflected by the object, the measurement waveform signal can be acquired from the light receiving amount distribution signal of the reflected light of the object.

In the above embodiment, the adjustment unit may adjust the sensitivity parameter of the light receiving amount distribution signal with respect to the reflected light so that the peak light receiving amount of the acquired measurement waveform signal becomes equal to or greater than a predetermined value.

According to the above embodiment, the sensitivity parameter of the light receiving amount distribution signal of the reflected light with respect to the object is adjusted so that the peak light receiving amount of the acquired measurement waveform signal becomes equal to or greater than the predetermined value. Thus, for example, by setting a threshold value smaller than a predetermined value to the measurement waveform signal, a signal due to noise (noise) or the like that may be mixed with the measurement waveform signal can be excluded.

In the above embodiment, the adjustment unit may set the range for adjusting the sensitivity parameter based on the reflectance of the object.

According to the above embodiment, the range in which the sensitivity parameter is adjusted is set based on the reflectance of the object. This can narrow (limit) the adjustment range of the sensitivity parameter, and can shorten the time required for adjusting the sensitivity parameter.

In the above embodiment, the adjustment unit may set the range for adjusting the sensitivity parameter based on the sensitivity parameter at the time of acquiring the waveform signal measured last time.

According to the embodiment, the range of adjusting the sensitivity parameter is set based on the sensitivity parameter when the waveform signal was measured last time. This can narrow (limit) the adjustment range of the sensitivity parameter, and can shorten the time required for adjusting the sensitivity parameter.

In the above embodiment, the sensitivity parameter may include at least one of a light projection amount of light, a light projection power of light, an exposure time of the light receiving section, and a gain (gain) of the light receiving section.

According to the above embodiment, the sensitivity parameter includes at least one of a light projection amount of light, a light projection power of light, an exposure time of the light receiving section, and a gain of the light receiving section. This makes it possible to easily change the amount of light received in the light-receiving amount distribution signal of the reflected light reflected by the object.

In the above embodiment, the predetermined value of the light receiving amount may be a value at which the light receiving amount is saturated.

According to the above embodiment, the predetermined value of the light receiving amount in the light receiving amount distribution signal of the reflected light of the object is a value at which the light receiving amount is saturated. Thus, saturation of the light receiving amount can be prevented in the light receiving amount distribution signal of the reflected light of the object obtained after the sensitivity parameter is adjusted.

In the embodiment, the method may further include: and a measuring unit for measuring the distance from the optical measuring device to the object based on the measurement waveform signal.

According to the above embodiment, the distance from the optical measuring device to the object is measured based on the measurement waveform signal. Thus, since the return light component contained in the light receiving amount distribution signal which becomes a noise component with respect to the measurement waveform signal is removed, the distance from the optical measurement device to the object can be measured based on the light receiving amount distribution signal of the reflected light reflected by the object, and the distance can be measured while suppressing the influence of noise, as compared with the case where the distance is measured.

In the embodiment, the method may further include: and an optical system configured to cause chromatic aberration of light along an optical axis direction, to irradiate the object with the light having the chromatic aberration, wherein the light includes a plurality of wavelength components, and the optical system condenses the reflected light, and the light receiving unit is configured to be able to detect the amount of light received for each of the wavelength components.

According to the above embodiment, the light is subjected to chromatic aberration along the optical axis direction, the object is irradiated with the light having the chromatic aberration, the light includes a plurality of wavelength components, and the reflected light is condensed, whereby the light receiving amount can be detected for each wavelength component. A white confocal optical measuring device capable of easily obtaining a measurement waveform signal from a light receiving amount distribution signal of reflected light from an object.

In addition, an optical measurement method according to another embodiment of the present invention includes: a light projecting step of emitting light to an object; a light reception step of obtaining a light reception amount distribution signal for each pixel; an acquisition step of acquiring a measurement waveform signal from a light receiving amount distribution signal of reflected light reflected by an object based on a light receiving amount distribution signal when the object is not present; and an adjustment step of adjusting a sensitivity parameter of the light receiving amount distribution signal with respect to the reflected light so as to acquire the measurement waveform signal when a part of the light receiving amount distribution signal of the reflected light is equal to or greater than a predetermined value.

According to the above embodiment, when a part of the light receiving amount distribution signal of the reflected light reflected by the object is equal to or greater than the predetermined value, the sensitivity parameter of the light receiving amount distribution signal of the reflected light with respect to the object is adjusted so as to acquire the measurement waveform signal. In this way, the light receiving amount distribution signal of the reflected light of the object obtained after the sensitivity parameter is adjusted can include the signal light component in the light receiving amount distribution signal of the reflected light of the object obtained after the sensitivity parameter is adjusted, while the light receiving amount is made smaller than a predetermined value, for example, without saturating the light receiving amount. Therefore, by adjusting the sensitivity parameter of the light receiving amount distribution signal of the reflected light reflected by the object, the measurement waveform signal can be acquired from the light receiving amount distribution signal of the reflected light of the object.

In the embodiment, the adjusting step may also include: the sensitivity parameter of the light receiving amount distribution signal with respect to the reflected light is adjusted so that the peak light receiving amount of the acquired measurement waveform signal becomes equal to or greater than a predetermined value.

According to the above embodiment, the sensitivity parameter of the light receiving amount distribution signal of the reflected light with respect to the object is adjusted so that the peak light receiving amount of the acquired measurement waveform signal becomes equal to or greater than the predetermined value. Thus, for example, by setting a threshold value smaller than a predetermined value to the measurement waveform signal, it is possible to eliminate a signal due to noise or the like that may be mixed with the measurement waveform signal.

In the embodiment, the adjusting step may also include: the range for adjusting the sensitivity parameter is set based on the reflectance of the object.

According to the above embodiment, the range in which the sensitivity parameter is adjusted is set based on the reflectance of the object. This can narrow (limit) the adjustment range of the sensitivity parameter, and can shorten the time required for adjusting the sensitivity parameter.

In the embodiment, the adjusting step may also include: the range of adjusting the sensitivity parameter is set based on the sensitivity parameter when the waveform signal was measured last time.

According to the embodiment, the range of adjusting the sensitivity parameter is set based on the sensitivity parameter when the waveform signal was measured last time. This can narrow (limit) the adjustment range of the sensitivity parameter, and can shorten the time required for adjusting the sensitivity parameter.

In the above embodiment, the sensitivity parameter may include at least one of a light projection amount of light, a light projection power of light, an exposure time of the light receiving section, and a gain of the light receiving section.

According to the above embodiment, the sensitivity parameter includes at least one of a light projection amount of light, a light projection power of light, an exposure time of the light receiving section, and a gain of the light receiving section. This makes it possible to easily change the amount of light received in the light-receiving amount distribution signal of the reflected light reflected by the object.

In the above embodiment, the predetermined value of the light receiving amount may be a value at which the light receiving amount is saturated.

According to the above embodiment, the predetermined value of the light receiving amount in the light receiving amount distribution signal of the reflected light of the object is a value at which the light receiving amount is saturated. Thus, saturation of the light receiving amount can be prevented in the light receiving amount distribution signal of the reflected light of the object obtained after the sensitivity parameter is adjusted.

In the embodiment, the method may further include: a measurement step of measuring a distance from the optical measurement device to the object based on the measurement waveform signal.

According to the above embodiment, the distance from the optical measuring device to the object TA is measured based on the measurement waveform signal. Thus, since the return light component contained in the light receiving amount distribution signal which becomes a noise component with respect to the measurement waveform signal is removed, the distance from the optical measurement device to the object can be measured based on the light receiving amount distribution signal of the reflected light reflected by the object, and the distance can be measured while suppressing the influence of noise, as compared with the case where the distance is measured.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the measurement waveform signal can be obtained from the light receiving amount distribution signal.

Drawings

Fig. 1 is a schematic configuration diagram illustrating a schematic configuration of an optical measuring apparatus according to the present embodiment.

Fig. 2 is a waveform diagram illustrating an example of a light receiving amount distribution signal of reflected light reflected by an object.

Fig. 3 is a waveform diagram illustrating an example of a light receiving amount distribution signal when no object is present.

Fig. 4 is a waveform diagram illustrating an example of a measurement waveform signal.

Fig. 5 is a waveform diagram illustrating another example of the light receiving amount distribution signal of the reflected light reflected by the object.

Fig. 6 is a signal diagram illustrating a first embodiment in which the adjusting unit shown in fig. 1 adjusts the amount of light projected.

Fig. 7 is a signal diagram illustrating a second embodiment in which the adjusting unit shown in fig. 1 adjusts the amount of light projected.

Fig. 8 is a signal diagram illustrating a third embodiment in which the adjusting unit shown in fig. 1 adjusts the amount of light projected.

Fig. 9 is a signal diagram illustrating a fourth embodiment in which the adjusting unit shown in fig. 1 adjusts the amount of light projected.

Detailed Description

Suitable embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, members denoted by the same reference numerals have the same or similar configurations.

First, the configuration of the optical measuring apparatus according to the present embodiment will be described with reference to fig. 1. The figure is a schematic configuration diagram illustrating a schematic configuration of the optical measurement apparatus 100 according to the present embodiment.

As shown in fig. 1, the optical measuring device 100 includes a light source 10, a light guide unit 20, a sensor head 30, a light receiving unit 40, a control unit 50, a storage unit 60, a display unit 70, and an operation unit 80. The optical measurement apparatus 100 measures the distance from the apparatus to the object TA at a predetermined measurement cycle, specifically, measures the distance from the sensor head 30 to the object TA at a predetermined measurement cycle. The optical measurement apparatus 100 may measure a change in distance, i.e., a displacement, with respect to a certain position at a predetermined measurement cycle.

The light source 10 is configured to emit light including a plurality of wavelength components. The light emitted from the light source 10 is directed toward the object TA. The light source of the present embodiment corresponds to an example of the "light projecting section" of the present invention.

The light source 10 is supplied with a predetermined current value at a predetermined ratio of the light projection time to the measurement period (hereinafter, the ratio of the light projection time to the measurement period is referred to as "light projection amount" (unit is%)) based on a control signal input from the control unit 50, and emits light of a predetermined power (hereinafter, referred to as "light projection power"). The amount of light projected, the power of light projected, and the like can be changed based on the control signal.

The light source 10 preferably emits light containing a plurality of wavelength components. In this case, the Light source 10 is configured to include, for example, a white Light Emitting Diode (LED), and generates white Light. However, the light emitted from the light source 10 is not limited to white light as long as it is light in a wavelength range covering the distance range required by the optical measurement apparatus 100.

Light directing portion 20 is used to spread light. The light guide 20 includes, for example, a first cable 21, a second cable 22, a third cable 23, and an optical coupler 24.

One end (left end in fig. 1) of the first cable 21 is optically connected to the light source 10. One end (right end in fig. 1) of the second cable 22 is optically connected to the sensor head 30. One end (left end in fig. 1) of the third cable 23 is optically connected to the light receiving portion 40. The other end (right end in fig. 1) of the first cable 21 and the other end (right end in fig. 1) of the third cable 23 are optically coupled to the other end (left end in fig. 1) of the second cable 22 via an optical coupler 24.

The optical coupler 24 transmits light incident from the first cable 21 to the second cable 22, and splits and transmits light incident from the second cable 22 to the first cable 21 and the third cable 23, respectively. Further, the light transmitted from the second cable 22 to the first cable 21 through the optical coupler 24 is terminated at the light source 10.

The optical coupler 24 is configured to include a fusion-drawn type (fusion-drawn type) optical coupler, for example. On the other hand, each of the first cable 21, the second cable 22, and the third cable 23 is made of, for example, an optical fiber. Each optical fiber may be a single core having a single core (core) or a multi-core having a plurality of cores.

The sensor head 30 irradiates light to the object TA. The sensor head 30 is used to collect reflected light from the object TA. The sensor head 30 of the present embodiment corresponds to an example of the "optical system" of the present invention.

The sensor head 30 includes, for example, a collimator lens 31, a diffraction lens 32, and an objective lens 33.

The collimator lens 31 is configured to convert light incident from the second cable into parallel light. The collimating lens 31 is composed of a single or multiple lenses. In addition, the collimator lens 31 also serves to condense light incident to the sensor head 30.

The diffraction lens 32 is configured to generate chromatic aberration of the parallel light in the optical axis direction. The objective lens 33 is configured to focus the light having the chromatic aberration and irradiate the object TA with the light. Since the on-axis chromatic aberration is generated by the diffraction lens 32, each wavelength of the light irradiated from the objective lens 33 has a focal point at a different distance (position).

In the example shown in fig. 1, light L1 of the first wavelength having a relatively long focal distance and light L2 of the second wavelength having a relatively short focal distance are shown. The light L1 with the first wavelength is focused (focused) on the surface of the object TA, and the light L2 with the second wavelength is focused (focused) in front of the object TA.

The light reflected by the surface of the object TA is condensed by the collimator lens 31 via the objective lens 33 and the diffraction lens 32, and enters the second cable 22. The light L1 of the first wavelength among the reflected lights is focused on the end face of the second cable 22 which is in the confocal point, and most of the light enters the second cable 22. On the other hand, the other wavelengths are not focused on the end surface of the second cable 22 and do not enter the second cable 22. The reflected light entering the second cable 22 is partially transmitted to the third cable 23 by the optical coupler 24, and is emitted to the light receiving unit 40.

In the case where the second cable 22 is an optical fiber, the core thereof corresponds to a pin hole (pin hole). Therefore, by reducing the core diameter of the optical fiber, the pinhole for collecting the reflected light is reduced, and light having a wavelength focused on the surface of the object TA can be stably detected.

The light receiving unit 40 is used to obtain a light receiving amount distribution signal, which will be described later, with respect to the light condensed by the sensor head 30. The light condensed by the sensor head 30 is, for example, reflected light reflected by the object TA. The light receiving unit 40 includes, for example, a collimator lens 41, a diffraction grating 42, an adjustment lens 43, a light receiving sensor 44, and a processing circuit 45.

The collimator lens 41 is configured to convert light incident from the third cable into parallel light. The diffraction grating 42 is configured to split (separate) the parallel light for each wavelength component. The adjustment lens 43 is configured to adjust the spot diameter of the light of each wavelength of the split light.

The light receiving sensor 44 is configured to detect the amount of received light for each wavelength component with respect to the dispersed light. The light receiving sensor 44 includes a plurality of light receiving elements. The light receiving elements are arranged one-dimensionally in correspondence to the light splitting direction of the diffraction grating 42. Thus, the light receiving elements are arranged corresponding to the dispersed light of the wavelength components, and the light receiving sensor 44 can detect the amount of received light for each wavelength component.

One light receiving element of the light receiving sensor 44 corresponds to one pixel. Therefore, the light receiving sensor 44 may be configured such that each of the plurality of pixels can detect the amount of light received. The light receiving elements are not limited to the one-dimensional arrangement, and may be two-dimensional arrangement. The light receiving elements are preferably two-dimensionally arranged on a detection surface including the diffraction grating 42 in the spectroscopic direction, for example.

Each light receiving element accumulates electric charge in accordance with the received light amount of light received during a predetermined exposure time period, based on a control signal input from the processing circuit 45. Each light receiving element outputs an electric signal corresponding to the accumulated electric charge during a period other than the exposure time, that is, during the non-exposure time, based on the control signal input from the processing circuit 45. Thereby, the light receiving amount received at the exposure time is converted into an electric signal.

The processing circuit 45 is configured to control the light reception by the light reception sensor 44. The processing circuit 45 is configured to perform signal processing for outputting the electric signals input from the light receiving elements of the light receiving sensor 44 to the control unit 50. The processing circuit 45 includes, for example, an amplifier circuit and an Analog-to-Digital (a/D) converter circuit. The amplifier circuit amplifies the electric signals input from the respective light receiving elements with a predetermined gain. The a/D conversion circuit samples (sampling), quantizes (quantizing), and encodes (coding) the amplified electrical signals of the respective light receiving elements, and converts the signals into digital signals. In this way, the light receiving amount detected by each light receiving element is converted into a digital value, and a distribution signal of the light receiving amount (hereinafter, simply referred to as "light receiving amount distribution signal") for each light receiving element, that is, for each pixel is obtained. The processing circuit 45 outputs the light receiving amount distribution signal to the control section 50. The predetermined exposure time of each light receiving element, the predetermined gain of the amplifier circuit, and the like can be changed based on the control signal.

The control unit 50 is configured to control operations of the respective units of the optical measurement apparatus 100. The control unit 50 is configured to implement each function described later by executing a program or the like stored in the storage unit 60. The present invention is configured to realize each function described later by executing a program or the like. The control Unit 50 includes, for example, a microprocessor such as a Central Processing Unit (CPU), a Read Only Memory (ROM), a Random Access Memory (RAM), a buffer Memory (buffer Memory), and the like.

The storage unit 60 is configured to store programs, data, and the like. The storage unit 60 includes, for example, a hard disk drive (hard disk drive), a solid state drive (solid state drive), and the like. The storage unit 60 stores various programs executed by the control unit 50, data necessary for executing the programs, and the like in advance. The storage unit 60 is configured to store a light receiving amount distribution signal obtained from the return light.

Here, an example of the light receiving amount distribution signal obtained by the light receiving unit 40 will be described with reference to fig. 2 and 3. Fig. 2 is a waveform diagram illustrating an example of a light receiving amount distribution signal of reflected light reflected by the object TA. Fig. 3 is a waveform diagram illustrating an example of the light receiving amount distribution signal when the object TA is not present. In fig. 2 and 3, the horizontal axis indicates the pixel (each light receiving element of the light receiving sensor 44), and the vertical axis indicates the light receiving amount.

As shown in fig. 2, the light receiving amount distribution signal of the reflected light reflected by the object TA includes a signal light component SC, which is the reflected light from the object TA, and a return light component RC, which is the reflected light inside the optical measurement apparatus 100. That is, a part of the light emitted from the light source 10 is not emitted from the sensor head 30, but is reflected inside the optical measurement apparatus 100 and returned. The light is referred to as return light, and the return light is generated at, for example, a connection portion between the second cable 22 and the sensor head 30, a connection portion between the second cable 22 and the optical coupler 24, a connection portion between the first cable 21 and the optical coupler 24, and the like. The return light appears as a return light component RC in the received light amount distribution signal.

On the other hand, since the return light is reflected light inside the optical measurement apparatus 100, the return light appears in the light receiving amount distribution signal even in a state where the object TA is not present and the reflected light from the object TA is not present. Therefore, as shown in fig. 3, it is considered that the light receiving amount distribution signal in the absence of the object TA is the same as or substantially the same as the return light component RC shown in fig. 2.

Therefore, the light receiving amount distribution signal shown in fig. 3 is obtained in a state where the object TA is not present, and is stored in the storage unit 60 in advance as a light receiving amount distribution signal obtained from the return light. Then, by obtaining the light receiving amount distribution signal shown in fig. 2 in a state where the object TA is present, and subtracting the light receiving amount distribution signal shown in fig. 3 from the light receiving amount distribution signal shown in fig. 2, for example, the return light component RC can be removed, and a measurement waveform signal having the signal light component SC as a main component can be acquired.

Returning to the description of fig. 1, the control unit 50 includes, for example, an acquisition unit 51, a measurement unit 52, and an adjustment unit 53 as its functional configuration.

The acquisition unit 51 is configured to acquire a measurement waveform signal from the light receiving amount distribution signal shown in fig. 2 based on the light receiving amount distribution signal shown in fig. 3.

Here, the measurement waveform signal acquired by the acquisition unit 51 will be described with reference to fig. 4. The figure is a waveform diagram illustrating an example of a measurement waveform signal. In fig. 4, the horizontal axis indicates the pixel (each light receiving element of the light receiving sensor 44), and the vertical axis indicates the normalized light receiving amount (normalized light receiving amount).

Specifically, the acquisition unit 51 first subtracts (subtracts) the light receiving amount distribution signal shown in fig. 3 when the object TA is not present, from the light receiving amount distribution signal of the reflected light reflected by the object TA shown in fig. 2, for each pixel. Then, the acquisition unit 51 multiplies the subtraction result by the exposure time at the time of obtaining the light receiving amount distribution signal of fig. 2 with respect to the exposure time at the time of obtaining the light receiving amount distribution signal of fig. 3, that is, by (the exposure time of the light receiving amount distribution signal of fig. 2)/(the exposure time of the light receiving amount distribution signal of fig. 3) (multiplication). Thereby, the difference in the amount of light received due to the exposure time is normalized. The storage unit 60 also stores the exposure time in advance together with the light receiving amount distribution signal of fig. 3. Then, the acquisition unit 51 divides the multiplication result by the light receiving amount distribution signal of fig. 3 for each pixel (divides). This corrects the blunting (ringing) caused by the return light component RC shown in fig. 2. In this manner, the acquisition unit 51 acquires the measurement waveform signal MS shown in fig. 4.

Returning to the description of fig. 1, the measuring unit 52 is configured to measure the distance from the optical measuring apparatus 100 to the object TA, more precisely, the distance from the sensor head 30 to the object TA, based on the measurement waveform signal MS acquired by the acquiring unit 51. In the example shown in fig. 1, the distance is a distance in the Z-axis direction.

As shown in fig. 4, the measurement waveform signal MS generally has a waveform in which the light receiving amount of a certain pixel becomes a peak. As described above, since the distance from the sensor head 30 to the point of focus differs depending on the wavelength, the pixel for measuring the peak received light amount of the waveform signal MS corresponds to the wavelength of the light irradiated from the sensor head 30 and focused on the object TA. The wavelength corresponds to a distance from the sensor head 30 to the object TA. In the example shown in fig. 1, the light L1 of the first wavelength focused on the surface of the object TA appears as the wavelength of the peak light receiving amount of the light receiving amount distribution signal.

Specifically, when the peak light receiving amount of the measurement waveform signal MS is 100%, the midpoint between two intersections of the line of the light receiving amount of 50% and the measurement waveform signal MS is obtained, and the wavelength λ corresponding to the pixel at the midpoint is obtained.

The relationship (correspondence) between the wavelength λ and the distance is stored in advance in the memory of the control unit 50, the storage unit 60, or the like. The measurement unit 52 measures the distance from the sensor head 30 to the object TA based on the measurement waveform signal MS by referring to the relationship.

In this way, by measuring the distance from the optical measurement apparatus 100 to the object TA based on the measurement waveform signal MS and removing the return light component RC included in the light receiving amount distribution signal shown in fig. 2 which becomes a noise component with respect to the measurement waveform signal MS, the distance from the optical measurement apparatus 100 to the object TA can be measured while suppressing the influence of noise, as compared with the case where the distance is measured based on the light receiving amount distribution signal of the reflected light reflected by the object TA.

The adjusting unit 53 is configured in such a manner that: when a part of the light receiving amount of the reflected light reflected by the object TA is equal to or greater than a predetermined value, the sensitivity parameter of the light receiving amount distribution signal with respect to the reflected light of the object TA is adjusted so as to acquire the measurement waveform signal MS.

Here, another example of the light receiving amount distribution signal obtained by the light receiving unit 40 will be described with reference to fig. 5. The graph is a waveform diagram illustrating another example of the light receiving amount distribution signal of the reflected light reflected by the object TA. In fig. 5, the horizontal axis indicates the pixel (each light receiving element of the light receiving sensor 44), and the vertical axis indicates the light receiving amount.

In the light receiving amount distribution signal of the reflected light of the object TA, a part of the light receiving amount may become equal to or larger than a predetermined value. As a result, as shown in fig. 5, the light receiving amount distribution signal includes a portion where the light receiving amount is not increased while maintaining the predetermined value. At this time, since the light receiving amount distribution signal shown in fig. 5 does not include the signal light component SC like the light receiving amount distribution signal shown in fig. 2, the acquisition unit 51 cannot acquire the measurement waveform signal MS from the light receiving amount distribution signal shown in fig. 5.

Therefore, the adjusting unit 53 adjusts the sensitivity parameter of the light receiving amount distribution signal with respect to the reflected light of the object TA when a part of the light receiving amount distribution signal when the object TA exists is equal to or more than a predetermined value as shown in fig. 5. Here, the light receiving amount of the light receiving amount distribution signal can be changed by adjusting a sensitivity parameter such as the amount of projected light. The sensitivity parameter is adjusted by the adjusting unit 53, so that the light receiving unit 40 can obtain a light receiving amount distribution signal including the signal light component SC as shown in fig. 2, and the measurement waveform signal MS is obtained by the obtaining unit 51. Therefore, when the amount of light received by a part of the light receiving amount distribution signal of the reflected light reflected by the object TA is equal to or greater than the predetermined value, the adjustment unit 53 adjusts the sensitivity parameter of the light receiving amount distribution signal of the reflected light with respect to the object TA so as to obtain the measurement waveform signal MS, and thereby the amount of light received is made smaller than the predetermined value, for example, the amount of light received is not saturated, and the light receiving amount distribution signal of the reflected light of the object TA after the sensitivity parameter is adjusted includes the signal light component SC shown in fig. 2, in the light receiving amount distribution signal of the reflected light of the object TA obtained after the sensitivity parameter is adjusted. Therefore, by adjusting the sensitivity parameter of the light receiving amount distribution signal of the reflected light reflected by the object TA, the measurement waveform signal can be acquired from the light receiving amount distribution signal of the reflected light of the object TA.

In the example shown in fig. 5, in the light receiving amount distribution signal of the reflected light of the object TA, the predetermined value of the light receiving amount is a value at which the light receiving amount receivable by the light receiving unit 40 is saturated. This prevents saturation of the light receiving amount in the light receiving amount distribution signal of the reflected light of the object TA obtained after the sensitivity parameter is adjusted.

In order to discriminate the measurement waveform signal MS acquired by the acquisition unit 51 from a signal due to noise or the like, the adjustment unit 53 preferably adjusts the sensitivity parameter of the light receiving amount distribution signal of the reflected light with respect to the object TA so that the peak light receiving amount of the acquired measurement waveform signal MS becomes equal to or greater than a predetermined value. Thus, for example, by setting a threshold value smaller than a predetermined value for the measurement waveform signal MS, it is possible to eliminate a signal due to noise or the like that may be mixed with the measurement waveform signal MS.

The sensitivity parameter of the light receiving amount distribution signal of the reflected light with respect to the object TA includes at least one of the light projecting amount of the light source 10, the light projecting power of the light source 10, the exposure time of each light receiving element of the light receiving sensor 44, and the gain of the amplifier circuit in the processing circuit 45. This makes it possible to easily change the amount of light received in the light-receiving amount distribution signal of the reflected light reflected by the object TA.

Hereinafter, the sensitivity parameter of the light receiving amount distribution signal of the reflected light reflected by the object TA will be described using the light projecting amount.

Now, the adjustment of the sensitivity parameter of the light receiving amount distribution signal of the reflected light with respect to the object TA by the adjusting unit 53 will be described with reference to fig. 6 to 9. Fig. 6 is a signal diagram illustrating a first embodiment in which the adjustment unit 53 shown in fig. 1 adjusts the amount of light projected. Fig. 7 is a signal diagram illustrating a second embodiment in which the adjustment unit 53 shown in fig. 1 adjusts the amount of light projected. Fig. 8 is a signal diagram illustrating a third embodiment in which the adjustment unit 53 shown in fig. 1 adjusts the amount of light projected. Fig. 9 is a signal diagram illustrating a fourth embodiment in which the adjustment unit 53 shown in fig. 1 adjusts the amount of light projected. In fig. 5 to 9, the horizontal axis represents time, and the vertical axis represents the light dose [% ].

(first embodiment)

For example, as shown in fig. 6, the adjusting unit 53 increases the amount of light projected in stages until the acquisition unit 51 acquires the measurement waveform signal MS. The step Vst of the light projection amount is set to 10 [% ], for example, and the step Tst of the light projection time of the light projection amount is set to 3 times (3 cycle parts) the measurement cycle, for example. The values of the step Vst of the light projection amount and the step Tst of the light projection time may be displayed on the display unit 70, which will be described later, and may be changed by the operation unit 80.

When the measurement waveform signal MS is not acquired even if the amount of light projected in a stepwise manner increases to a predetermined value, 100 [% ] in the example shown in fig. 6, the adjustment unit 53 decreases the amount of light projected to the lower limit value Vmin. The lower limit value Vmin of the light input amount is set to, for example, 10 [% ]. The value of the lower limit Vmin of the light projection amount may be set to be variable by the operation unit 80 by displaying the value on the display unit 70 in the same manner as the step Vst of the light projection amount and the step Tst of the light projection time.

After the light projection amount is decreased to the lower limit value Vmin, the adjustment unit 53 increases the light projection amount again in stages until the measurement waveform signal MS is acquired by the acquisition unit 51.

(second embodiment)

For example, as shown in fig. 7, the adjusting unit 53 decreases the amount of light projection in stages until the acquisition unit 51 acquires the measurement waveform signal MS. The step Vst of the light projection amount is set to 10 [% ], for example, and the step Tst of the light projection time of the light projection amount is set to 3 times (3 cycle parts) the measurement cycle, for example. The values of the step Vst of the light projection amount and the step Tst of the light projection time may be displayed on the display unit 70 in the same manner as in the first embodiment, and may be changed by the operation unit 80.

When the measurement waveform signal MS is not acquired even if the amount of light projected that is reduced in stages reaches the preset lower limit value Vmin, for example, 10 [% ], the adjustment unit 53 increases the amount of light projected to a predetermined value, 100 [% ] in the example shown in fig. 6. The value of the lower limit value Vmin set as the light projection amount may be displayed on the display unit 70 in the same manner as in the first embodiment, and may be changed by the operation unit 80.

After increasing the amount of light to a predetermined value, the adjusting unit 53 decreases the amount of light again in stages until the acquisition unit 51 acquires the measurement waveform signal MS.

(third embodiment)

When the reflectance of the object TA is known in advance, it is sufficient that the sensitivity parameter of the light receiving amount distribution signal of the reflected light with respect to the object TA is adjusted within a predetermined range. At this time, for example, as shown in fig. 8, the adjusting unit 53 increases the amount of light projected in a stepwise manner within the adjustment range AR1 until the measurement waveform signal MS is acquired by the acquiring unit 51. The adjustment range AR1 is a range of the amount of light to be projected set based on the reflectance of the object TA, and is, for example, a range having the amount of light to be projected corresponding to the reflectance of the object TA as a median value. The adjustment range AR1 is displayed on the display unit 70 and designated by the operation unit 80.

Similarly to the first embodiment, the adjusting unit 53 increases the amount of light projected in steps by the step Vst of the amount of light projected and the step Tst of the light projecting time, and when the measurement waveform signal MS is not acquired even if the amount of light projected reaches the upper limit value of the adjustment range AR1, the adjusting unit 53 decreases the amount of light projected until the lower limit value of the adjustment range AR 1. Thereafter, the adjustment unit 53 increases the amount of light projected in stages again within the adjustment range AR1 until the acquisition unit 51 acquires the measurement waveform signal MS.

In the third embodiment, the example in which the adjustment unit 53 increases the amount of light projected in stages within the adjustment range AR1 is shown, but the present invention is not limited to this. As in the second embodiment, the adjustment unit 53 may decrease the amount of light projected in stages within the adjustment range AR 1. At this time, when the measurement waveform signal MS is not acquired even if the amount of light projection reaches the lower limit value of the adjustment range AR1, the adjustment unit 53 increases the amount of light projection to the upper limit value of the adjustment range AR 1.

By setting the adjustment range AR1 of the sensitivity parameter based on the reflectance of the object TA in this manner, the adjustment range of the sensitivity parameter can be narrowed (limited), and the time required for adjusting the sensitivity parameter can be shortened.

(fourth embodiment)

When the acquisition unit 51 is able to acquire the measurement waveform signal MS, it is sufficient that the sensitivity parameter is adjusted within a predetermined range when the sensitivity parameter of the light receiving amount distribution signal of the reflected light with respect to the object TA is stored in the memory of the control unit 50, the storage unit 60, or the like. At this time, for example, as shown in fig. 9, the adjusting unit 53 increases the amount of light projected in a stepwise manner within the adjustment range AR2 until the measurement waveform signal MS is acquired by the acquiring unit 51. The adjustment range AR2 is a range of the light projection amount set based on the light projection amount Vpre at the time of acquiring the previous measurement waveform signal MS, for example, a range having the light projection amount at the time of acquiring the previous measurement waveform signal MS as a central value.

Similarly to the first embodiment, the adjusting unit 53 increases the amount of light projected in steps by the step Vst of the amount of light projected and the step Tst of the light projecting time, and when the measurement waveform signal MS is not acquired even if the amount of light projected reaches the upper limit value of the adjustment range AR2, the adjusting unit 53 decreases the amount of light projected until the lower limit value of the adjustment range AR 2. Thereafter, the adjustment unit 53 increases the amount of light projected in stages again within the adjustment range AR2 until the acquisition unit 51 acquires the measurement waveform signal MS.

In the fourth embodiment, the example in which the adjustment unit 53 increases the amount of light projected in stages within the adjustment range AR2 is shown, but the present invention is not limited to this. As in the second embodiment, the adjustment unit 53 may decrease the amount of light projected in stages within the adjustment range AR 2. At this time, when the measurement waveform signal MS is not acquired even if the amount of light projection reaches the lower limit value of the adjustment range AR2, the adjustment unit 53 increases the amount of light projection to the upper limit value of the adjustment range AR 2.

In this way, by setting the adjustment range AR2 of the sensitivity parameter based on the sensitivity parameter at the time of acquiring the previous measured waveform signal MS, the adjustment range of the sensitivity parameter can be narrowed (limited), and the time taken to adjust the sensitivity parameter can be shortened.

Returning to the description of fig. 1, the display unit 70 outputs information. Specifically, the display unit 70 is configured to display, for example, setting contents, an operation state, a communication state, and the like. The display section 70 includes, for example, a seven-segment display or an eleven-segment display having a large number of bits, and a display lamp emitting light in multiple colors.

The operation unit 80 is used for inputting information by an operation of a user (user). The operation unit 80 includes, for example, buttons, switches, and the like. At this time, when the user operates a button, a switch, or the like, a signal corresponding to the operation is input to the control unit 50. Then, the control unit 50 generates data corresponding to the signal, thereby inputting information to the optical measuring apparatus 100.

In the present embodiment, an example in which the optical measurement apparatus 100 is of a white confocal system is shown, but the present invention is not limited to this. The optical measuring apparatus of the present invention may be a triangulation system, for example. In this case, the optical measuring apparatus may include the following components: a light projecting section for emitting light to an object; a light receiving unit for obtaining a light receiving amount distribution signal for each pixel; an acquisition unit that acquires a measurement waveform signal from a light-receiving amount distribution signal of reflected light reflected by the object TA, based on the light-receiving amount distribution signal when the object TA is not present; and an adjusting unit 53 that adjusts a sensitivity parameter of the light receiving amount distribution signal of the reflected light with respect to the object TA so as to acquire the measurement waveform signal MS when a part of the light receiving amount distribution signal of the reflected light reflected by the object TA is equal to or greater than a predetermined value.

As described above, according to the optical measurement apparatus 100 and the optical measurement method of the present embodiment, when the amount of light received by a part of the light-receiving amount distribution signal of the reflected light reflected by the object TA is equal to or greater than the predetermined value, the sensitivity parameter of the light-receiving amount distribution signal of the reflected light with respect to the object TA is adjusted so as to acquire the measurement waveform signal MS. Thus, in the light receiving amount distribution signal of the reflected light of the object TA obtained after the sensitivity parameter is adjusted, the light receiving amount is made smaller than a predetermined value, for example, the light receiving amount is not saturated, and the light receiving amount distribution signal of the reflected light of the object TA after the sensitivity parameter is adjusted includes the signal light component SC shown in fig. 2. Therefore, by adjusting the sensitivity parameter of the light receiving amount distribution signal of the reflected light reflected by the object TA, the measurement waveform signal can be acquired from the light receiving amount distribution signal of the reflected light of the object TA.

The embodiments described above are intended to facilitate understanding of the present invention, and are not intended to be restrictive. The elements included in the embodiments, their arrangement, materials, conditions, shapes, sizes, and the like are not limited to the examples, and may be appropriately changed. In addition, the configurations shown in different embodiments may be partially replaced or combined with each other.

(attached note)

1. An optical measurement device (100) comprising:

a light source (10) that emits light toward an object (TA);

a light receiving unit (40) configured such that each of the plurality of pixels can detect the amount of light received, and that obtains a light receiving amount distribution signal for each pixel;

an acquisition unit (51) that acquires a measurement waveform signal (MS) from a light-receiving amount distribution signal of reflected light reflected by an object (TA) on the basis of the light-receiving amount distribution signal when the object (TA) is not present; and

an adjusting unit (53) adjusts a sensitivity parameter for the light receiving amount distribution signal of the reflected light so as to acquire the measurement waveform signal (MS) when a part of the light receiving amount distribution signal of the reflected light is equal to or greater than a predetermined value.

9. An optical measurement method comprising:

a light projection step of emitting light to an object (TA);

a light reception step of obtaining a light reception amount distribution signal for each pixel;

an acquisition step of acquiring a measurement waveform signal (MS) from a light reception amount distribution signal of reflected light reflected by the object (TA) based on the light reception amount distribution signal when the object (TA) is not present; and

and an adjustment step of adjusting the sensitivity parameter of the light receiving amount distribution signal of the reflected light so as to acquire the measurement waveform signal (MS) when a part of the light receiving amount distribution signal of the reflected light is equal to or greater than a predetermined value.

Description of the symbols

10: light source

20: light guide part

21: first cable

22: second cable

23: third cable

24: optical coupler

30: sensor head

31: collimating lens

32: diffractive lens

33: objective lens

40: light receiving part

41: collimating lens

42: diffraction grating

43: adjusting lens

44: light receiving sensor

45: processing circuit

50: control unit

51: acquisition unit

52: measuring part

53: adjusting part

60: storage unit

70: display unit

80: operation part

100: optical measuring device

AR1, AR 2: adjustment range

L1, L2: light (es)

MS: measuring waveform signals

RC: return light component

SC: signal light component

TA: object

Tst: stride length

Vmin: lower limit value

Vpre: light projection amount

Vst: stride length

λ: wavelength of light