JP3806485B2 - Ranging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a distance measuring apparatus that measures the distance to the subject by measuring the amount of light incident from the subject.
[0002]
[Prior art]
Conventionally, a distance measuring device used for an imaging device such as a camera is generally designed on the assumption that light irradiating a subject is constant, but since most of artificial lighting is turned on by a commercial power source, The light that irradiates the subject often pulsates.
[0003]
Various techniques have been proposed in the past, for example, in Japanese Patent Application Laid-Open No. 61-144504 and Japanese Patent Application Laid-Open No. 56-14906 in order to reduce the influence of AC light from artificial lighting on the distance measuring device. Yes.
[0004]
That is, in Japanese Patent Laid-Open No. 61-144504, when an external light detection unit detects that an external light signal component is included in a signal from a light receiving unit, and when the external light detection unit detects external light. And a control unit that cancels the calculation operation of the distance calculation unit.When external light is detected by the external light detection unit, the external light harmful to the distance measurement operation is prevented by not detecting the distance. A technique related to a distance detection device that prevents erroneous distance measurement due to the above is disclosed.
[0005]
Further, in Japanese Patent Laid-Open No. 61-14906, even if the reflected light from the object to be measured includes a pulsating wave, a section where the rate of change of the pulsating wave is the smallest is detected, and the distance measurement is performed in that section. A technology relating to a distance detecting device that emits a light beam and receives reflected light to perform signal processing to prevent erroneous signal output and realize accurate distance detection is disclosed.
[0006]
[Problems to be solved by the invention]
However, in the technique disclosed in Japanese Patent Laid-Open No. 61-144504, the distance measurement is stopped when harmful light is incident due to the fluctuation of the light.
[0007]
Further, the technique disclosed in Japanese Patent Laid-Open No. 56-14906 is limited to a technique for so-called active AF that separates distance measuring light projected from the camera side from background light, and can be applied to passive AF. There wasn't.
[0008]
In the case of active AF, the distance measurement light emission time is extremely short compared to the time period of change of the AC light source, and the distance measurement light may be projected in a place where the fluctuation of the AC light source is small. In the case of AF, it is necessary to integrate for a long time, such as when the subject brightness is low, and it is difficult to avoid the influence of AC fluctuation, and it is hoped to solve such a problem. It was.
[0009]
The present invention has been made in view of the above problems, and an object of the present invention is to use a so-called passive AF camera that performs distance measurement using information on an image of a subject. It is an object of the present invention to provide a distance measuring device for performing quick and accurate distance measurement even when incident on a sensor.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a distance measuring device according to a first aspect of the present invention detects a plurality of subject images incident from different fields of view, and determines the subject based on a relative difference between the plurality of subject image positions. In the distance measuring apparatus for measuring the distance to the object, the detection means for detecting the fluctuation of light from the artificial light source that is lit by alternating current and illuminates the subject, and in response to the detection result of the fluctuation of the light, The detection start timing is when the brightness of the light from the artificial light source is increasing or decreasing. And control means for controlling.
[0011]
In the distance measuring device according to the second aspect, a light beam from an object incident through two openings having parallax is imaged on a photoelectric conversion element array, and a relative interval between two image signals obtained thereby is determined. In a distance measuring device for detecting a distance to an object by detection, a monitor means for generating an output signal when an image signal from the photoelectric conversion element array reaches an appropriate accumulation level, and an AC power source for illuminating the object In response to the presence of the artificial light source driven by the light source and the detection means for detecting the rate of change of brightness with respect to time, and the rate of change of brightness of the artificial light source with respect to time, Control means for controlling the image signal accumulation operation to wait for a half cycle of the artificial light source; It is characterized by comprising.
[0012]
According to a third aspect of the present invention, there is provided a distance measuring device that converts a plurality of subject images incident from different fields of view into a photoelectric sensor array. By subject image signal from In a distance measuring device that detects and measures a distance to the subject based on a relative difference between the plurality of image positions, Detection means for detecting the amount of light fluctuation and its increase / decrease direction by an artificial light source that repeatedly measures the subject image signal and illuminates the subject by alternating current lighting, and the amount of light fluctuation by the artificial light source and its direction of increase / decrease Correction means for calculating the fluctuation amount due to the artificial light source and correcting the fluctuation amount from the measured subject image signal It is characterized by comprising.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
In the following description, first, the AF sensor output is A / D-converted according to the time required to reach a predetermined determination level, and secondly, the accumulation level of the AF sensor is monitored by the peak level. 3 assumes that the artificial light changes sinusoidally.
[0017]
First, FIG. 1 shows and describes the configuration of a distance measuring apparatus according to the first embodiment.
The first embodiment relates to the accumulation timing adjustment, and is adopted in an external light type two-image interval detection AF device. The active AF light receiving circuit is diverted by a separately provided pulsating light monitor unit 7 to pulsate light. The state of is detected. Then, the accumulation operation is performed when the pulsating light is in one of the increasing tendency or the decreasing tendency, and when it is not, the accumulation operation is waited for a half cycle.
[0018]
As shown in the figure, light receiving lenses 1a and 1b are arranged to receive an image of a subject 8, and a plurality of photodiodes are arranged at positions where the subject images of the light receiving lenses 1a and 1b are formed. The sensor arrays 2a and 2b are arranged. Further, the outputs of the sensor arrays 2a and 2b are connected to the input of the CPU 10 via the A / D converter 3, and the output of the CPU 10 is connected to the inputs of the sensor arrays 2a and 2b via the integration control unit 4. Has been.
[0019]
Further, in order to detect the pulsating flow of the AC light source 9, a light receiving lens 5 is disposed at a predetermined position, and a sensor 6 for detecting the pulsating light is disposed behind the light receiving lens 5. The output of the sensor 6 is connected to the input of the CPU 10 via the pulsating light monitor unit 7.
[0020]
In such a configuration, the image of the subject 8 is guided to the sensor arrays 2a and 2b formed of photodiode rows by the light receiving lenses 1a and 1b, and is received and photoelectrically converted by the sensor arrays 2a and 2b. The sensor arrays 2a and 2b are controlled by the integration controller 4, and each output a photoelectric conversion signal according to the intensity of incident light. The output photoelectric conversion signal is converted into a digital value by the A / D converter 3 and input to the CPU 10 including a one-chip microcomputer or the like.
[0021]
Here, as a photoelectric conversion signal output and A / D conversion method, a method of integrating the output photocurrent of the photodiode into the capacitor and counting the time when the integration result reaches a predetermined level is adopted. Can do.
[0022]
That is, as shown in FIG. 2A, the integrated voltage V tends to increase with time t. However, as the amount of light increases, that is, the subject image becomes brighter, the time to reach the predetermined level V1 becomes faster. As a result, the determination time t1 is shortened. That is, if the determination time t1 is shortened, it is determined as “bright”, and if the determination time t1 is increased, it is determined as “dark”.
[0023]
However, when the light of the artificial illumination 9 that pulsates the subject 8 is irradiated, the integrated waveform is disturbed as shown in FIG. 2B, and as shown in FIGS. 2C and 2D. Depending on the state and timing of the pulsating flow, even when the brightness is the same, the time to reach the predetermined level V1 becomes t2 or t3, and an error occurs.
[0024]
Therefore, in this first embodiment, in order to avoid this error, the light from the subject 8 is received by the sensor 6 via the light receiving lens 5 and whether or not this light is pulsating is monitored. The detection is performed by the unit 7, the result is input to the CPU 10, and the CPU 10 controls the integration operation of the distance measurement by a control sequence (FIG. 3) described later.
[0025]
Hereinafter, the control of the CPU 10 will be described with reference to the flowchart of FIG. First, the CPU 10 detects how the light incident from the subject 8 fluctuates by the pulsating light monitor unit 7 (step S1). Based on this result, the CPU 10 determines the timing for starting the integration operation (step S2).
[0026]
Specifically, in the case of pulsating light as shown in FIG. 2C, integration is performed as it is, and when illumination is pulsating as shown in FIG. The integration is started after waiting for the timing (steps S3 and S4). By such control, the integration result as shown in FIG. 2B is always fixed at t1, so that variations during distance measurement can be suppressed.
[0027]
Here, FIG. 4 shows the above pulsating light. Monitor Show details.
That is, the CPU 10 determines the period of the pulsating light by the pulsating light monitor unit 7 (step S1). S11 ) And integrate (step S12 ), Integrate again at the timing half a cycle of the pulsating cycle (step S14 ), Step above S12 , S14 Add the results of the two integrations S15 ), And the integration result is obtained in the form of averaging t1 and t2 in FIG. Therefore, even in this case, stable ranging is possible even under pulsating light. When the cycle of the commercial power source is determined, the above step S 11 In, only detection of whether under pulsating light is performed.
[0028]
Next, FIG. 5 shows a specific configuration example of the pulsating light monitor unit 7 and will be described.
In the figure, reference numeral 5 denotes a sensor composed of a photoelectric conversion element, reference numeral 11 denotes a preamplifier, and reference numeral 12 denotes a current amplification transistor. By these actions, the output photocurrent of the sensor is amplified and sent to the compression diode 13 as the collector current of the transistor 12. However, when the level of the compression diode 13 is lowered, the one side input of the operational amplifier 17 is lowered, so that the base of the transistor 15 is raised and the sensor output is not amplified and flows as a collector current of the transistor 15. That is, when the amplifier 17 is operating, the output of the sensor is hardly amplified, and the base potential of the transistor 15 at that time is stored by the capacitor 16 even if the amplifier 17 stops operating. Reference numerals 18 and 19 denote a diode and a constant current source for inputting the reference voltage Vref to the + side terminal of the amplifier 17. Reference numeral 14 denotes a buffer circuit for monitoring the voltage of the compression diode.
[0029]
In such a configuration, when the operational amplifier 17 is operating, the level of the compression diode 13, that is, the output of the buffer 14 is constant. However, when the operational amplifier 17 is deactivated by the timing signal generation means 20, the fluctuation from the photocurrent output from the sensor 5 when the operational amplifier 17 is activated is output to the buffer 14.
[0030]
This will be described with reference to the timing chart of FIG.
Now, when the pulsating light as shown in FIG. 6A is incident on the sensor 6, if the operation of the operational amplifier 17 is stopped at the timing of H in FIG. 6B, the output of the buffer 14 is as shown in FIG. As shown in (c). That is, since the base potential of the transistor 15 is controlled by the voltage held in the capacitor 16 at the final timing during operation, the fluctuation of the pulsating light is output as Vp.
[0031]
The CPU 10 determines whether the level is higher or lower than Vref by the comparator 14b. By this action, it becomes possible for the CPU 10 to determine whether the pulsating light is increasing or decreasing depending on whether Vp increases or decreases with respect to the reference voltage Vref.
[0032]
The operation of the application example of the first embodiment of the present invention using the pulsating light monitoring unit 7 will be described below with reference to the flowchart of FIG.
In this application example, first, the CPU 10 detects the magnitude relationship of Vp at a predetermined time (steps S21 and S22), and measures the distance only when these satisfy the relationship of Vp1> Vp2 (step S23). , S24). As a result, distance measurement is performed only in either of the cases shown in FIGS. 2C and 2D, and the time until the integration reaches V1 shown in FIG. 2B is t1, t2. The accuracy of distance measurement can be improved.
[0033]
As described above, in the distance measuring device according to the first embodiment, even when the light that illuminates the subject is light that fluctuates in an alternating manner, stable ranging characteristics can be obtained and applied to the camera. High precision focusing can be achieved.
[0034]
The circuit configuration of the pulsating flow monitor unit 7 shown in FIG. 5 is the same as that of the active AF light receiving circuit. Therefore, the sensor is an active AF sensor and means for projecting distance measuring light is provided. In addition, it can be expected to apply an active AF to project a light from a light projecting unit (not shown) to a subject having darkness or no contrast, thereby enabling distance measurement with higher accuracy.
[0035]
Next, a distance measuring apparatus according to the second embodiment will be described.
The second embodiment relates to the adjustment of the accumulation timing, and repeatedly monitors the accumulation level of the AF sensor, and detects the state of pulsating light based on the change in time until the monitor signal is output. Then, the accumulation operation is performed when the pulsating light is in one of the decreasing trend or the increasing trend, and when it is not, the accumulation operation is waited for a half cycle.
[0036]
FIG. 8A is a diagram illustrating a configuration of a distance measuring apparatus according to the second embodiment.
As shown in the figure, in the second embodiment, the passive distance measuring device having the same structure as that of FIG. 1 including the light receiving lenses 1a and 1b, the sensor arrays 2a and 2b, the A / D converter 3 and the like is used. The integration monitor unit 4 for monitoring the integration level of the output photocurrents of the sensor arrays 2a and 2b is provided, and the CPU 10 performs control to suppress the integration level within the dynamic range of the signal level defined by the power supply voltage of the circuit. I can do it. Such a contrivance is common in the passive AF technique, but in the second embodiment, the pulsating light detection described above is performed using the output of the monitor unit 4. .
[0037]
Here, FIG. 8B illustrates an example of the integral monitor unit 4 and will be described.
In the figure, reference numerals 21a to 21c denote photodiodes constituting the sensor array, and reference numerals 22a to 22c denote integration capacitors for integrating these output photocurrents. Reference numerals 25a to 25c denote reset switches that discharge these capacitors and initialize the integrated voltage. Reference numerals 23a to 23c denote comparators that compare the reference voltage Vref and the integration voltage when integration is started after the reset switch is turned OFF.
[0038]
The reset Sw is controlled all at once by the integration control unit 26, but when one of the comparators 23 a to 23 c is inverted, an OR signal is output by the OR circuit 24.
[0039]
Although not explicitly shown in FIG. 8B, the voltage stored in the integration capacitors 22a to 22c is a voltage hold circuit and a multiplexer configured with the number of bits equal to the number of pixels of the sensors 21a to 21c. 8 is input in parallel to a known signal readout circuit composed of a combination circuit with the circuit, an analog shift register circuit, or the like, and sequentially reads out the voltage information of each bit in series after the integration operation is aborted. The A / D converter 3 performs A / D conversion.
[0040]
FIG. 8C is a timing chart showing the operation of the above circuit.
As shown in FIG. 8C, when the interval between the SW OFF timing and the OR signal generation timing is Tor, this is a value depending on the maximum value of the amount of light input to each sensor. Depending on the length of this signal, the sensitivity can be switched by switching the integral determination level Vref or by switching the capacities of the capacitors 22a to 22c. The sensitivity can be switched within a predetermined time regardless of the brightness level of the subject. It becomes possible to end the integration control within the dynamic range.
[0041]
The characteristic of the second embodiment is that this Tor signal is applied to detect the pulsating light, and no special sensor or circuit is required as in the case of FIG. Inexpensive and compact. When the subject is illuminated with pulsating light, the time of Tor varies depending on the state of the pulsating light at that time due to the phenomenon shown in FIG. In accordance with such a principle, the second embodiment detects pulsating light.
[0042]
Hereinafter, the above operation will be described with reference to the flowchart of FIG.
As shown in FIG. 9, if Tor is detected twice over a predetermined time corresponding to a half cycle of the pulsating light source (steps S31 to S33), the light decreases at one timing and the light at the other timing. Since it increases, it is possible to predict which state the pulsating light at the time of distance measurement will be as shown in FIGS.
[0043]
Therefore, here, integration is started only when Tor1 becomes larger than Tor2 (step S34), and the state of pulsating light at the start of integration is made uniform (step S35). By such control, the integration is always performed under a constant condition, so that the result does not change every time the distance is measured and the accuracy is improved.
[0044]
Next, FIG. 10 shows and describes the configuration of a distance measuring apparatus according to the third embodiment.
In the third embodiment, the accumulation process is sampled to determine whether or not to continue the accumulation. As will be described later, the peak value of the accumulation level is monitored by the peak detection circuit, and the continuation and re-execution of the integration are determined. It is characterized by doing.
[0045]
In the same figure, the light receiving elements constituting the sensor array, the sensors 21a to 21c, the reset switches 25a (25b and 25c are not shown because they become complicated), and the integrating capacitors 22a to 22c have already been described, and thus the description thereof is omitted.
[0046]
Reference numeral 31 is a current source, and reference numerals 30a to 30c are monitor transistors. The integrated voltage is monitored on the basis of the integrated voltage of the capacitors 22a to 22c. The voltage is input as a voltage close to (VBE) (see FIG. 11A). Accordingly, when the buffer output VM is monitored by the A / D converter 33, the CPU 10 receives the largest amount of light among the sensors 21a to 21c and outputs the maximum photocurrent, but the integrated voltage VCMAX can be determined. it can.
[0047]
Hereinafter, a method for detecting pulsating light by the distance measuring apparatus having such a configuration will be described with reference to FIGS.
FIG. 11A shows an integrated waveform when the subject is irradiated with DC light, while FIG. 11B shows an integrated waveform when pulsating light is irradiated. In these drawings, the horizontal axis indicates time, the vertical axis indicates voltage, and FIG. 11B shows a state in which the monitor voltage is wavy due to the influence of pulsating light. From these figures, it can be seen that the slope of integration at t1 and t2 changes depending on the condition of pulsating light.
[0048]
The operation of the third embodiment will be described below with reference to the flowchart of FIG. In this sequence, the integrated voltage at times t1 and t2 is monitored, and the rate of change with time is compared to suppress the influence of pulsating light.
[0049]
That is, first, the CPU 10 discloses the timing of the timer (step S51), starts integration (step S52), monitors the integration voltage at the timings t1 and t2, and sets the results as V1 and V2 (steps). S53 to S56).
[0050]
Here, if the time from the start of integration to the time t1 is equal to the time from the time t1 to the time t2, the rate of change is equal when there is no pulsating light, so that V1 and V2 -V1 are equal. On the other hand, when there is pulsating light, as shown in FIG. 11 (b), V1> V2-V1.
[0051]
Since such fluctuations are caused by disturbances in the distance measurement results, in the third embodiment, step S57 Only when V1> V2-V1 S58 In step S62, the integration voltage is reset and reintegration is performed under other conditions. At this time, Integral The start timing is shifted by a half period of one pulsating light cycle, and the condition of V1> V2−V1 is satisfied at the time of integration again.
[0052]
As described above, in the third embodiment, the state of integration of the sensor that receives the strongest light input to the sensor array is monitored to determine the pulsating light. Therefore, no special sensor is required. Further, since the monitoring is performed while integrating, pulsating light is detected at the same time as integration, and high-precision distance measurement with a reduced time lag is possible without performing useless integration operation.
[0053]
Next, a fourth embodiment will be described with reference to FIGS.
The fourth embodiment corrects the sensor output according to the pulsating state, repeatedly monitors the accumulation level of the AF sensor, detects the pulsating light state based on the AF sensor output, and The AF sensor output is corrected in accordance with the change state of the pulsating light, and the accumulation result is corrected as appropriate.
[0054]
The operation of this embodiment will be described below with reference to the flowchart of FIG.
In the fourth embodiment, the pulsating light state is monitored before and after the distance measurement (step S42) instead of the pulsating light countermeasure in which integration is performed in accordance with the timing of the pulsating light as described above (step S41, 43) As a result, the size determination is performed based on M1 and M2 (step S44), and the AF accuracy deterioration due to the pulsating light is prevented by the measure of correcting the distance measurement result (steps S45 and 46).
[0055]
For example, as shown in FIG. 14A, in the integrated waveform under pulsating light illumination, the error ΔAD affects the increase direction or affects the downward direction depending on the state of the pulsating light at that time. Therefore, at the start of integration (step S41 Pulsating light M1 at the time of integration) Finish Time (step S43 When the level is greater than the level M2 at the time of (2), it is considered that the integration level has decreased with respect to the ideal as shown in FIG. 14B, and in the opposite case, the integration level has increased. Conceivable.
[0056]
Steps based on the above thinking S44 Then, when M1 is larger than M2, FIG. Assumption And step S45 To correct for + direction, reverse step S44 Branch to N and step S46 At − Correct the direction.
[0057]
As described above, according to the fourth embodiment, as in the first embodiment described above, it is possible to quickly stabilize even under pulsating light without shifting the timing or repeating distance measurement many times. Distance measurement is possible.
[0058]
In addition, the following invention is contained in the said embodiment of this invention.
(1) A distance measuring means that includes a storage type photoelectric sensor and optically measures the distance from the apparatus to an object;
Detection means for detecting the presence of incident light whose brightness by an AC light source changes periodically;
When the AC light source is detected, the distance measuring means performs the accumulation operation when the brightness of incident light by the AC light source is increasing or decreasing. Control means for controlling the operation timing of
A distance measuring device comprising:
(2) The detection unit includes a storage unit that stores a light amount at a predetermined timing, and a fluctuation component detection unit that detects a light amount at the next timing as a difference from the light amount at the predetermined timing. The distance measuring device according to 1).
(3) The detection means detects light fluctuations from a light amount incident on the subject image detection means at a predetermined timing and a light amount incident on the storage photoelectric sensor at a timing different from this timing. The distance measuring device according to (1).
(4) A light beam from an object entering through two openings having parallax is imaged on a storage type photoelectric conversion element array, and a relative interval between two image signals obtained thereby is detected and the object is detected. In a distance measuring device that calculates the distance to an object,
Control means for initializing the accumulation level of the photoelectric conversion element array and controlling the accumulation operation;
Monitoring means for generating an output signal when an image signal from the photoelectric conversion element array reaches an appropriate accumulation level;
Comprising
Repeatedly measure the time from the start of accumulation of the photoelectric conversion element array to the generation of the monitor signal, and when this time has a predetermined relationship with the previous measurement result, invalidate the latest accumulation result A distance measuring device.
[0059]
【The invention's effect】
As described above, according to the present invention, in a camera using so-called passive AF that performs distance measurement using information on an image of a subject, even when the pulsating light is incident on an AF sensor, A distance measuring device for performing accurate distance measurement can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a distance measuring apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram showing the relationship between time and sensor integration time.
FIG. 3 is a flowchart showing control of a CPU.
FIG. 4 is a flowchart showing details of the pulsating light monitor in step S1 of FIG.
FIG. 5 is a diagram showing a detailed circuit configuration of a pulsating light monitor unit 7;
6 is a time chart showing the operation of the pulsating light monitor unit 7. FIG.
FIG. 7 is a flowchart showing an operation of an application example of the present embodiment using a pulsating light monitor unit 7;
FIG. 8 is a diagram for explaining a distance measuring apparatus according to a second embodiment.
FIG. 9 is a flowchart showing the operation of the distance measuring apparatus according to the second embodiment.
FIG. 10 is a diagram illustrating a configuration of a distance measuring device according to a third embodiment.
FIG. 11 is a diagram showing a method for detecting pulsating light in the third embodiment.
FIG. 12 is a flowchart showing the operation of the distance measuring apparatus according to the third embodiment.
FIG. 13 is a flowchart showing an operation according to the fourth embodiment.
FIG. 14 is a timing chart showing an operation according to the fourth embodiment.
[Explanation of symbols]
1 Receiving lens
2 Sensor array
3 A / D converter
4 Integration control unit
5 Light receiving lens
6 Sensor
7 Pulse flow light monitor
8 Subject
9 AC light source
10 CPU

Claims (3)

In a distance measuring device that detects a plurality of subject images incident from different fields of view and measures the distance to the subject based on a relative difference between the plurality of subject image positions,
AC detecting means for detecting fluctuations in light from an artificial light source that lights up and illuminates the subject;
In response to the light fluctuation detection result, the detection start timing of the subject image signal is set to one of the states when the brightness of the light from the artificial light source is increasing or decreasing. Control means to control at a certain time ,
A distance measuring device comprising: A light beam from an object entering through two openings having parallax is imaged on the photoelectric conversion element array, and the distance between the two image signals obtained thereby is detected to obtain the distance to the object. In the distance measuring device,
Monitoring means for generating an output signal when an image signal from the photoelectric conversion element array reaches an appropriate accumulation level;
Detection means for detecting the presence of an artificial light source driven by an AC power source that illuminates the object, and the rate of change of brightness over time;
In response to the rate of change of the brightness of the artificial light source with respect to time, control means for controlling the image signal storage operation to wait for a half cycle of the artificial light source ;
A distance measuring device comprising: In a ranging device that detects a plurality of subject images incident from different fields of view by subject image signals from a photoelectric sensor array and measures the distance to the subject based on a relative difference between the plurality of image positions,
Detecting means for repeatedly measuring the subject image signal and detecting a fluctuation amount of light by an artificial light source that illuminates the subject by alternating current lighting and an increase / decrease direction thereof;
A correction means for calculating the fluctuation amount due to the artificial light source from the fluctuation amount of the light due to the artificial light source and the increase / decrease direction, and correcting the fluctuation amount from the measured subject image signal
A distance measuring device comprising:

Images