JP2021085674A - Optical measuring instrument and light source control method - Google Patents

Abstract

To provide an optical measuring instrument and a light source control method which can appropriately control an emission intensity of a light source when an amount of light received by an imaging device is saturated.SOLUTION: An optical measuring instrument 1 comprises: an irradiation unit 11 which includes a laser light source 111 and irradiates an object M with light emitted from the laser light source 111; an imaging device 122 which receives the light reflected by the object M to output an image signal indicative of a light intensity waveform corresponding to a distance to the object M; a photodetector 13 which has a dynamic range wider than that of the imaging device 122 and receives the light reflected by the object M to output a light detection signal; and a light source control unit 35 which, when an amount of light received by the imaging device 122 is saturated, calculates a target value of laser power of the laser light source 111 on the basis of an output value of the light detection signal and controls the laser light source 111 on the basis of the target value.SELECTED DRAWING: Figure 1

Description

The present invention relates to an optical measuring device and a light source control method for irradiating an object with light from a light source to measure the shape of the object in a non-contact manner.

Conventionally, there is known an optical measuring device that measures the shape of an object in a non-contact manner by irradiating the object with light such as a laser beam and imaging a light spot formed on the object (for example, a patent). Reference 1).

The above-mentioned optical measuring device calculates the distance to the object to be measured based on the image formation position of the light spot in the captured image by utilizing the principle of the triangulation method. Specifically, as shown in FIG. 8, the captured image captured by the optical measuring device forms a light intensity waveform indicating the image brightness with respect to the pixel position, and corresponds to the peak of the light intensity waveform. The pixel position Px corresponds to the distance to the object.
In such an optical measuring device, when the reflectance of the surface of the object becomes high, the amount of light received by the imaging unit increases, and the peak height of the light intensity waveform becomes high. Then, as shown in FIG. 9, when the light receiving amount of the image sensor is saturated, it becomes difficult to identify the peak of the light intensity waveform, and as a result, the distance to the object cannot be accurately measured.

Therefore, in the optical measuring device described in Patent Document 1, the light receiving amount of the image pickup element is calculated based on the captured image, and the light emission intensity of the light source is feedback-controlled so that the light receiving amount of the image pickup element is within a predetermined range. Is being done.

JP-A-2002-139311

However, even when the feedback control described in Patent Document 1 is performed in the above-mentioned optical measuring device, the feedback control cannot catch up during scanning of the object, and the amount of light received by the image sensor becomes saturated. there is a possibility. In this case, since the light receiving amount of the image sensor cannot be accurately calculated based on the captured image, the emission intensity of the light source cannot be appropriately controlled, which affects the measurement accuracy.

An object of the present invention is to provide an optical measuring device and a light source control method capable of appropriately controlling the emission intensity of a light source when the light receiving amount of the image sensor is saturated.

The optical measuring device of the present invention includes a light source, an irradiation unit that irradiates an object with light emitted from the light source, and receives the light reflected by the object to obtain a distance to the object. An image pickup element that outputs an image signal showing a corresponding light intensity waveform, and a light detector that has a wider dynamic range than the image pickup element and receives the light reflected by the object and outputs a light detection signal. When the light receiving amount of the image pickup element is saturated, the target value of the light emission intensity of the light source is calculated based on the output value of the light detection signal, and the light source is controlled based on the target value. It is characterized by having a part and.

The optical measuring device of the present invention is configured so that each of the image pickup element and the photodetector receives the light reflected by the object, and when the light emission intensity of the light source increases, it is output from the image pickup unit. The peak value of the image signal and the output value of the light detection signal output from the photodetector increase linearly with each other. Here, since the photodetector has a wider dynamic range than the image sensor, there is a possibility that the amount of light received by the photodetector will be saturated even when the amount of light received by the image sensor is saturated. Low. Therefore, when the light receiving amount of the image sensor is saturated, the light source control unit is such that the light receiving amount of the image sensor becomes less than or equal to the saturation level based on the output value of the light detection signal output from the photodetector. The target value, which is the value of the light emission intensity, can be calculated. Then, the light source control unit can quickly recover the image pickup device from the saturated state by controlling the light source based on the target value.
Therefore, according to the optical measuring device of the present invention, when the light receiving amount of the image sensor is saturated, the light emission intensity of the light source can be appropriately controlled, and as a result, the measurement accuracy can be improved.
In the present invention, the photodetector may directly or indirectly receive the light reflected by the object.

The light source control method of the present invention includes an irradiation unit that includes a light source and irradiates an object with light emitted from the light source, and receives the light reflected by the object according to the distance to the object. An image pickup element that outputs an image signal showing a light intensity waveform, and a light detector that has a wider dynamic range than the image pickup element and receives the light reflected by the object and outputs a light detection signal. In the light source control method executed in the optical measuring device including, when the light receiving amount of the imaging element is saturated, the target value of the light emission intensity of the light source is based on the output value of the light detection signal. It is characterized by including a target value calculation step for calculating the target value and a light source control step for controlling the light source based on the target value.
According to the light source control method of the present invention, similarly to the above-mentioned measuring device, the light emission intensity of the light source can be appropriately controlled when the light receiving amount of the image sensor is saturated, and as a result, the measurement accuracy can be improved. ..

In the light source control method of the present invention, in a coordinate system in which the emission intensity of the light source is on the X-axis and the signal level of the image signal or the light detection signal is on the Y-axis, the peak of the image signal with respect to the change in emission intensity. When the straight line representing the change in the value is the imaging sensitivity straight line and the straight line representing the change in the output value of the light detection signal with respect to the change in the light emission intensity is the light detection sensitivity straight line, the target value calculation step is the light detection signal. A step of calculating the light detection sensitivity straight line for the object based on the output value of, a step of converting the light detection sensitivity straight line for the object into the imaging sensitivity straight line for the object, and an imaging for the object. It is preferable to include a step of calculating the value of the light emission intensity at which the peak value of the image signal is adjusted to a predetermined value as the target value based on the sensitivity straight line.
The predetermined value at which the peak value of the image signal is adjusted may be a value lower than the saturation level of the image sensor.
According to the present invention, a target value regarding the emission intensity of a light source can be appropriately calculated.

The measurement method of the present invention further includes an information acquisition step of acquiring correlation information including an offset and an angle difference between the imaging sensitivity straight line and the light detection sensitivity straight line, and the target value calculation step includes the correlation information. Based on this, it is preferable to convert the light detection sensitivity straight line for the object into the imaging sensitivity straight line for the object.
According to the present invention, the target value regarding the emission intensity of the light source can be calculated more appropriately.

In the measurement method of the present invention, in the information acquisition step, with respect to a plurality of reference objects having different reflectances, an image quality average straight line which is an average of the imaging sensitivity straight lines with respect to the plurality of reference objects and the plurality of reference objects. The step of acquiring the light detection sensitivity average straight line, which is the average of the light detection sensitivity straight lines corresponding to the above, and the offset and the angle difference of the imaging sensitivity average straight line with respect to the light detection sensitivity average straight line are calculated as the correlation information. It is preferable to include the steps.
Since the present invention uses average data between a plurality of reference objects having different reflectances, it is possible to appropriately calculate a target value regarding the emission intensity of a light source for objects having various reflectances.

The schematic diagram which shows the optical measuring apparatus which concerns on one Embodiment of this invention. The graph for demonstrating the information acquisition process in the light source control method of the said embodiment. The graph which illustrates the imaging sensitivity average straight line in the information acquisition process of the said embodiment. The graph which illustrates the light detection sensitivity average straight line in the information acquisition process of the said embodiment. The flowchart for demonstrating the light source control method of the said Embodiment. The graph for demonstrating the target value calculation process in the light source control method of the said embodiment. The figure which shows the probe head which concerns on the modification of the said embodiment. A graph illustrating a light intensity waveform. It is a graph exemplifying a light intensity waveform, and is a graph for explaining a problem in the prior art.

An embodiment of the present invention will be described with reference to the drawings.
[Measuring device configuration]
In FIG. 1, the optical measuring device 1 according to the present embodiment is a three-dimensional measuring device that measures the shape of an object M in a non-contact manner, and moves the probe head 10 and the probe head 10 to an arbitrary position. It includes a mechanism 20 and a control unit 30 that measures the shape of the object M based on a signal from the probe head 10.

(Probe head)
As shown in FIG. 1, the probe head 10 includes an irradiation unit 11, an imaging unit 12, and a photodetector 13.
The irradiation unit 11 includes a laser light source 111 that emits laser light and an irradiation optical system 112.
The laser light source 111 includes, for example, a laser diode. The laser light source 111 emits laser light according to a control signal (target value of laser power) input from the light source control unit 35 described later. That is, the laser power of the laser light source 111 is controlled by the light source control unit 35.
The laser power of the laser light source 111 corresponds to the light intensity of the present invention.

The irradiation optical system 112 is an optical system that irradiates the measurement point of the object M with the laser light emitted from the laser light source 111. The irradiation optical system 112 includes, for example, a collimating lens that parallelizes the laser light emitted from the laser light source 111.

The image pickup unit 12 includes a light receiving optical system 121 and an image sensor 122 that receives laser light via the light receiving optical system 121.
The light receiving optical system 121 is an optical system that forms an image of the laser beam reflected by the object M on the light receiving surface of the image sensor 122. The light receiving optical system 121 includes, for example, a condensing lens that collects laser light reflected by the object M.

The image sensor 122 is, for example, an image sensor such as a CCD, and has a plurality of pixels arranged in one direction or two directions. The image sensor 122 receives the laser light transmitted through the light receiving optical system 121 and outputs an image signal showing a light intensity waveform. The light intensity waveform is a waveform indicating image brightness with respect to a pixel position, as in the prior art (see FIG. 8). The pixel position Px corresponding to the peak of the light intensity waveform of the image signal differs depending on the distance to the object M.

The photodetector 13 is, for example, a photodiode, and the photodetector 13 receives the laser light (scattered light) reflected by the object M and outputs a light detection signal according to the amount of received light. The photodetector 13 has a wider dynamic range than the image sensor 122 of the image pickup unit 12.

(Movement mechanism)
The moving mechanism 20 is a mechanism for moving the probe head 10 to an arbitrary position. Further, the moving mechanism 20 is provided with a position detection sensor (not shown) for detecting the position of the probe head 10.
The specific configuration of the moving mechanism 20 is not particularly limited, and for example, the probe head 10 may be held at the tip of the articulated arm so that the angle of each arm of the articulated arm can be changed. In this case, an angle detection sensor such as a rotary encoder that detects the rotation angle of each arm is provided. As a result, the control unit 30 can calculate the position and posture of the probe head 10 based on the arm length of each arm and the angle between the arms.
Further, the moving mechanism 20 may be configured to hold the probe head 10 in a portal frame that moves in the XYZ direction. That is, the moving mechanism 20 is provided on a column that can move in the Y direction, a beam that is held by the column and is parallel to the X direction, a slider that can move on the beam in the X direction, and a slider that moves in the Z direction. A movable head holding member may be provided, and the probe head 10 may be held by the head holding member. In such a configuration, the moving mechanism 20 includes a Y scale that detects the position of the column in the Y direction, an X scale that detects the position of the slider in the X direction, and a Z scale that detects the position of the head holding member in the Z direction. It may be configured. Thereby, the XYZ coordinates of the probe head 10 can be detected. The head holding member may be provided with an angle changing portion for changing the angle of the probe head 10. In this case, the posture of the probe head 10 can be detected by providing the angle detecting sensor in the angle changing portion.

(Control unit)
The control unit 30 is composed of a computer, and includes a calculation unit 31 and a storage unit 37. As shown in FIG. 1, the calculation unit 31 reads and executes various programs recorded in the storage unit 37 to obtain the measurement control unit 32, the shape calculation unit 33, the saturation determination unit 34, the light source control unit 35, and information acquisition. It functions as a unit 36.

By controlling the probe head 10 and the moving mechanism 20, the measurement control unit 32 sequentially irradiates a plurality of measurement points of the object M with laser light emitted from the irradiation unit 11, and an image signal is emitted for each measurement point. And get the photodetection signal.
The shape calculation unit 33 calculates the distance from the probe head 10 to the measurement point of the object M based on the image signal output from the image pickup unit 12. Further, the shape calculation unit 33 calculates the three-dimensional coordinates of the measurement point based on the calculated distance to the measurement point and the position and posture of the probe head 10. Then, the shape calculation unit 33 measures the surface shape of the object M by connecting the calculated three-dimensional coordinates to a plurality of measurement points on the object M.

The saturation determination unit 34 determines whether or not the amount of light received by the image sensor 122 is saturated based on the image pickup signal.
When the light receiving amount of the image pickup element 122 is saturated, the light source control unit 35 controls the laser power of the laser light source 111 by outputting a control signal (a new target value of the laser power) to the laser light source 111. To do.
The information acquisition unit 36 acquires various information necessary for control by the light source control unit 35.
The storage unit 37 stores a program and various information for operating the control unit 30.

[Light source control method]
Hereinafter, the light source control method implemented in the optical measuring device 1 of the present embodiment will be described.
(Pre-processing)
The optical measuring device 1 of the present embodiment performs an information acquisition step using a plurality of reference objects having different reflectances before measuring the object M to be measured.

First, the probe head 10 irradiates the reference object with a laser beam in a state where a reference object instead of the object M is set. The information acquisition unit 36 acquires the peak value of the image signal and the output value of the light detection signal each time the laser power is changed by a predetermined amount, and stores them in the storage unit 37. In the present embodiment, data is acquired by using a black reference material having a relatively low reflectance and a white reference material having a relatively high reflectance as reference materials.

Next, the information acquisition unit 36 acquires data for each of the white reference object and the black reference object in the XY coordinate system in which the laser power is the X-axis component and the output level of the image signal or the light detection signal is the Y-axis component. And draw a linear approximation straight line to calculate various straight lines.

Specifically, as shown in FIG. 2, for the white reference object, an imaging sensitivity straight line Li-W, which is a linear function (straight line) representing a change in the peak value of the image signal with respect to a change in laser power, is calculated. Further, for the white reference object, a photodetection sensitivity straight line Ld−W, which is a linear function (straight line) representing a change in the output value of the photodetection signal with respect to a change in laser power, is calculated.
Similarly, as shown in FIG. 2, for the black reference object, an imaging sensitivity straight line Li-B, which is a linear function (straight line) representing a change in the peak value of the image signal with respect to a change in laser power, is calculated. Further, for the black reference object, a photodetection sensitivity straight line Ld-B, which is a linear function (straight line) representing a change in the output value of the photodetection signal with respect to a change in laser power, is calculated.

Next, as shown in FIG. 2, the coordinates of the intersection Pi where the two imaging sensitivity straight lines Li-W and Li-B intersect each other are calculated. Further, as shown in FIG. 3, an imaging sensitivity average straight line Li-Avg, which is the average of the two imaging sensitivity linear lines Li-W and Li-B, is calculated, and the imaging sensitivity average linear line Li-Avg is an arbitrary axis (for example,). The angle θi formed with the X-axis) is calculated.
Similarly, as shown in FIG. 2, the coordinates of the intersection Pd where the two photodetection sensitivity straight lines Ld-W and Ld-B intersect are calculated. Further, as shown in FIG. 4, the light detection sensitivity average straight line Ld-Avg, which is the average of the two light detection sensitivity straight lines Ld-W and Ld-B, is calculated, and the light detection sensitivity average straight line Ld-Avg is arbitrary. The angle θd formed between the axis (for example, the X axis) is calculated.

Next, the offset amount Δr of the imaging sensitivity average straight line Li-Avg with respect to the photodetection sensitivity average straight line Ld-Avg is obtained. In the present embodiment, this offset amount Δr can be calculated as the coordinate difference (ΔX, ΔY) of the intersection Pd with respect to the intersection Pi.
Further, the angle difference Δθ of the imaging sensitivity average straight line Li-Avg with respect to the photodetection sensitivity average straight line Ld-Avg is obtained. In the present embodiment, this angle difference can be calculated as the difference of the angle θd with respect to the angle θi.

The information acquisition unit 36 stores the offset amount Δr and the angle difference Δθ calculated above in the storage unit 37 as correlation information indicating the correlation between the imaging sensitivity straight line and the light detection sensitivity straight line. Further, the intersection Pd where the two photodetection sensitivity straight lines Ld-W and Ld-B intersect is stored in the storage unit 37 as the start point information of the photodetection sensitivity straight line.

Here, the shapes formed by the imaging sensitivity straight lines Li-W and Li-B for each reference object and the shapes formed by the photodetection sensitivity straight lines Ld-W and Ld-B for each reference object are similar to each other. That is, the angle θis (see FIG. 3) sandwiched between the imaging sensitivity straight lines Li-W and Li-B for each reference object and the angle θds sandwiched between the photodetection sensitivity straight lines Ld-W and Ld-B for each reference object. (See FIG. 4) is almost equal to.
Therefore, when the photodetection sensitivity straight line for the object M is estimated in the measurement process described later, the photodetection is performed by performing arithmetic processing based on the correlation information (offset amount Δr and angle difference Δθ) obtained above. The sensitivity straight line can be converted into an imaging sensitivity straight line for the object M.

(Measurement processing)
The optical measuring device 1 of the present embodiment controls the laser power of the laser light source 111 while measuring the shape of the object M. Hereinafter, the control method of the laser light source 111 carried out during the measurement of the object M will be described with reference to the flowchart of FIG.
Before the measurement of the object M, it is assumed that an appropriate target value for the laser power is set in the optical measuring device 1.

First, the measurement control unit 32 controls the probe head 10 and the moving mechanism 20 to irradiate the measurement point of the object M with the laser light emitted from the irradiation unit 11 to acquire an image signal and a photodetection signal. (Step S1).
The image signal obtained in step S1 is used by the shape calculation unit 33 to measure the coordinates of the measurement point. Since the processing by the shape calculation unit 33 is the same as the conventional one, the details will be omitted.

The saturation determination unit 34 determines whether or not the amount of light received by the image sensor 122 is saturated based on the image signal acquired by the measurement control unit 32 (step S2). The method for determining the saturation state of the image pickup device 122 is not particularly limited, but the determination may be made based on the waveform shape of the image signal, or may be determined by comparing the peak value of the image signal with the threshold value.

When it is determined that the image sensor 122 is not saturated (No in step S2), the light source control according to the image signal obtained in the immediately preceding step S1 ends.

When it is determined that the image sensor 122 is saturated (Yes in step S2), the light source control unit 35 stores the output value of the light detection signal obtained in the immediately preceding step S1 and the storage unit 37. The target value of the laser power is calculated based on the various information (step S3).

Specifically, as shown in FIG. 6, the target value of the laser power currently set in the XY coordinate system in which the laser power is the X-axis component and the signal level of the image signal or the light detection signal is the Y-axis component. A point P1 having PWs as the X coordinate and the output value V1 of the light detection signal obtained in the immediately preceding step S1 as the Y coordinate is obtained. Then, a straight line passing through this point P1 and the start point (intersection point Pd) of the light detection sensitivity straight line is calculated as a light detection sensitivity straight line Ld-M with respect to the object M, and the slope (X) of this light detection sensitivity straight line Ld-M is calculated. The angle θd−M) with respect to the axis is calculated.

Next, the angle difference Δθ stored in the storage unit 37 is added to the angle θd-M of the photodetection sensitivity straight line Ld-M, and the offset amount stored in the storage unit 37 of this light detection sensitivity straight line Ld-M is added. Move by Δr. As a result, the photodetection sensitivity straight line Ld-M with respect to the object M is converted into the imaging sensitivity straight line Li-M with respect to the object M. Then, using the converted imaging sensitivity straight line Li-M, the value of the laser power at which the peak value of the image signal becomes a predetermined value Vt (for example, a value of 90% of the saturation level of the image signal) is set as a new target value PWt. calculate.

Note that FIG. 6 refers to a point P2 in which the currently set target value PWs of the laser power is the X coordinate and the peak value (saturation level) of the image signal obtained in the immediately preceding step S1 is the Y coordinate. Shown for. However, this point P2 does not correspond to the actual light receiving amount of the image sensor 122, and the point P3 shown on the imaging sensitivity straight line Li-M corresponds to the actual light receiving amount.

After that, the light source control unit 35 outputs the target value PWt calculated in step S3 as a control signal to the laser light source 111. As a result, the laser power of the laser light source 111 is controlled to the target value PWt (step S4). As a result, the light source control according to the image signal obtained in the immediately preceding step S1 is completed.

The flowchart of FIG. 5 described above is carried out for each of the plurality of measurement points of the object M until the scanning of the measurement area set in the object M is completed. When the scanning of the measurement area set in the object M is completed, the shape calculation unit 33 connects the coordinates obtained for the plurality of measurement points and measures the shape of the object M.

In the flowchart of FIG. 5, after step S1, the timing at which the shape calculation unit 33 measures the coordinates of the measurement point based on the image signal may be independent of steps S2 to S4 related to light source control. Alternatively, the shape calculation unit 33 may measure the coordinates of the measurement point after it is determined in step S2 that the image sensor 122 is not saturated. If it is determined in step S2 that the image sensor 122 is saturated, step S1 is performed at the same measurement point as the previous time after the laser power is controlled in step S4, and based on the obtained image signal. The coordinates of the measurement point may be measured.

[Effect of this embodiment]
The optical measuring device 1 of the present embodiment is configured such that each of the imaging unit 12 and the photodetector 13 receives the light reflected by the object M, and the laser power of the laser light source 111 increases. The peak value of the image signal output from the imaging unit 12 and the output value of the light detection signal output from the photodetector 13 increase linearly with each other. Here, since the photodetector 13 has a wider dynamic range than the image pickup unit 12, the light reception amount of the photodetector 13 can be saturated even when the light reception amount of the image sensor 122 is saturated. The sex is low. Therefore, when the light receiving amount of the image sensor 122 is saturated, the light source control unit 35 does not saturate the light receiving amount of the image sensor 122 based on the output value of the light detection signal output from the photodetector 13. The target value, which is the value of the laser power of, can be calculated. Then, the light source control unit 35 can quickly recover the image pickup device 122 from the saturated state by controlling the laser light source 111 based on the target value.
Further, the light source control method in the optical measuring device 1 of the present embodiment has the same effect by performing the target value calculation step and the light source control step described as the functions of the light source control unit 35.

Further, in the present embodiment, the target value calculation step converts the photodetection sensitivity straight line Ld-M for the object M into the imaging sensitivity straight line Li-M for the object M, and the laser is based on the imaging sensitivity straight line Li-M. Calculate the power. Thereby, an appropriate target value of the laser power can be calculated.

Further, in the present embodiment, the information acquisition step of acquiring the correlation information including the offset and the angle difference between the image pickup sensitivity straight line and the photodetection sensitivity straight line is further carried out. As a result, the target value calculation step can appropriately convert the light detection sensitivity straight line Ld-M into the imaging sensitivity straight line Li-M, and as a result, the target value of the laser power can be calculated more appropriately.

Further, in the present embodiment, since the information acquisition process uses the average data between a plurality of reference objects having different reflectances, the target value of the laser power is more appropriate for the objects having various reflectances. Can be calculated.

In the prior art such as Patent Document 1, since the feedback control in which the set value of the laser power is sequentially changed and converged is performed, the time required for the light source control affects the measurement speed. On the other hand, in the present embodiment, since it is not necessary to perform feedback control as in the prior art, the time required for controlling the laser light source 111 can be minimized, and the influence on the measurement speed is small.

[Modification example]
The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the range in which the object of the present invention can be achieved are included in the present invention.
For example, in the above embodiment, the irradiation unit 11 has the laser light source 111, but may have a light source of a type other than the laser light source 111. In this case, the light source control unit 35 may control the emission intensity of the light source.
Further, in the above embodiment, the photodetector 13 is arranged so as to directly receive the light reflected by the object M, but the present invention is not limited to this. That is, another reflecting object may intervene in the optical path between the photodetector 13 and the object M, and the photodetector 13 is arranged so as to indirectly receive the light reflected by the object M. May be done.
For example, in the modified example shown in FIG. 7, the photodetector 13A receives the reflected light reflected by the image sensor 122 after being reflected by the object M. Even with such a modified example, the same effect as that of the above-described embodiment can be obtained.

The plurality of reference materials used in the information acquisition step of the above embodiment are not limited to the black reference material and the white reference material, and other reference materials having a reflectance may be used.

In the above embodiment, the offset amount Δr and the angle difference Δθ of the imaging sensitivity average straight line Li-Avg with respect to the photodetection sensitivity average straight line Ld-Avg are acquired as correlation information, but the present invention is not limited to this. For example, the image sensitivity straight line and the photodetection sensitivity straight line for any reference object may be used, and the offset amount Δr and the angle difference Δθ of the light detection sensitivity straight line with respect to the image pickup sensitivity straight line may be acquired as correlation information.

In the above embodiment, when the image sensor 122 is not saturated, the light source control unit 35 does not change the target value set for the laser power, but the present invention is not limited to this. For example, the light source control unit 35 may feedback control the laser power based on the image signal as in the prior art.

1 ... Optical measuring device, 10 ... Probe head, 11 ... Irradiation unit, 111 ... Laser light source, 112 ... Irradiation optical system, 12 ... Imaging unit, 121 ... Light receiving optical system, 122 ... Imaging element, 13, 13A ... Photodetection Instrument, 20 ... movement mechanism, 30 ... control unit, 31 ... calculation unit, 32 ... measurement control unit, 33 ... shape calculation unit, 34 ... saturation determination unit, 35 ... light source control unit, 36 ... information acquisition unit, 37 ... storage Department.

Claims (5)

An irradiation unit that includes a light source and irradiates an object with light emitted from the light source.
An image sensor that receives the light reflected by the object and outputs an image signal showing a light intensity waveform according to the distance to the object.
A photodetector that has a wider dynamic range than the image sensor, receives the light reflected by the object, and outputs a light detection signal.
When the light receiving amount of the image sensor is saturated, a light source control unit that calculates a target value of the light emission intensity of the light source based on the output value of the light detection signal and controls the light source based on the target value. An optical measuring device characterized by: An irradiation unit that includes a light source and irradiates an object with light emitted from the light source.
An image sensor that receives the light reflected by the object and outputs an image signal showing a light intensity waveform according to the distance to the object.
A light source control method performed in an optical measuring device including a photodetector having a wider dynamic range than the image sensor, receiving the light reflected by the object, and outputting a photodetection signal. There,
When the light receiving amount of the image sensor is saturated, a target value calculation step of calculating a target value of the light emission intensity of the light source based on the output value of the light detection signal, and a target value calculation step.
A light source control method including a light source control step of controlling the light source based on the target value. In the light source control method according to claim 2,
In a coordinate system in which the light emission intensity of the light source is on the X-axis and the signal level of the image signal or the light detection signal is on the Y-axis, a straight line representing a change in the peak value of the image signal with respect to the change in the light emission intensity is imaged. When the sensitivity straight line is defined and the straight line representing the change in the output value of the light detection signal with respect to the change in light emission intensity is defined as the light detection sensitivity straight line.
The target value calculation process is
A step of calculating the photodetection sensitivity straight line for the object based on the output value of the photodetection signal, and
A step of converting the light detection sensitivity straight line for the object into the imaging sensitivity straight line for the object, and
A light source including a step of calculating the value of the emission intensity at which the peak value of the image signal is adjusted to a predetermined value as the target value based on the imaging sensitivity straight line with respect to the object. Control method. In the light source control method according to claim 3,
Further comprising an information acquisition step of acquiring correlation information including an offset and an angle difference between the imaging sensitivity straight line and the photodetection sensitivity straight line.
The target value calculation step is a light source control method characterized in that the light detection sensitivity straight line for the object is converted into the imaging sensitivity straight line for the object based on the correlation information. In the light source control method according to claim 4,
The information acquisition process is
For a plurality of reference objects having different reflectances, the average image sensitivity straight line which is the average of the imaging sensitivity straight lines for the plurality of reference objects and the light which is the average of the light detection sensitivity straight lines corresponding to the plurality of reference objects. The process of acquiring the detection sensitivity average straight line and
A light source control method comprising a step of calculating an offset and an angle difference between the light detection sensitivity average straight line and the imaging sensitivity average straight line as the offset and the angle difference of the correlation information.

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