JPH09229681A - Distance measuring device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To reduce the distance measurement time when performing continuous distance measurement or multi-point distance measurement. SOLUTION: In the case of continuous distance measurement, steps S101 to S1
In 04, the driving frequency of the skim CCD sensor and the initial value of the shutter opening time are set, and steps S105, 106,
At 109 to 112, the magnitude of the external light amount received from the output of the sensor is compared with a predetermined amount, and if the external light amount is large, the frequency and the shutter opening time are changed so that the external light amount becomes small, and then measured at steps S107 and S108. Distance is set, and the frequency and shutter opening time at that time are set. From the second time, steps S102 to S112 are omitted and step S1 is performed.
At 14, the distance is measured using the set value. In the case of multi-point distance measurement, the distance of another distance measurement point is measured using the frequency of the distance measurement point in the center of the screen and the shutter opening time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring device used in a camera or the like for optically measuring a distance to a measuring object.

[0002]

2. Description of the Related Art Distance measuring devices for measuring the distance to a measuring object have been well known. The applicant has proposed a distance measuring device using a sensor array and a cyclic shift register (hereinafter, skim CCD sensor) capable of transferring and accumulating charges from the sensor array. This distance measuring device includes a light projecting unit for projecting signal light onto an object to be measured, a first sensor array and a second sensor array for receiving reflected light from the object to be measured, and for signal transfer and addition. A light receiving unit including a CCD is provided, and the reflected light from the object to be measured is photoelectrically converted and accumulated and added in synchronization with turning on / off of the light emitting unit. Further, it has an electronic shutter function for controlling the storage time once so that the sensor output and the like are not saturated by unnecessary external light components.

The structure of this distance measuring device is shown in FIG. In FIG. 4, 101 is a first light receiving lens forming a first optical path, 102 is a second light receiving lens forming a second optical path,
Reference numeral 103 denotes a light projecting lens for projecting a spot on an object to be measured.
Reference numeral 04 is a light emitting element (IRED) that performs on / off operation to perform spot light projection. Reference numeral 105 denotes a first sensor array in which a large number of photoelectric conversion elements are linearly arranged, 106 denotes a second sensor array, 107 denotes an electronic shutter function for discarding charges photoelectrically converted by each sensor of the first sensor array 105. Which is the first clear portion where the charge is discarded by the ICG pulse. Reference numeral 108 denotes a second clear unit having an electronic shutter function of discarding charges photoelectrically converted by each sensor of the second second sensor array 106, and charges are generated by the ICG pulse similarly to the first electronic shutter unit 107. Be thrown away.

Reference numeral 109 denotes a first charge storage unit, which includes an ON storage unit and an OFF storage unit, and charges the ON and OFF periods of the light emitting element 4 from the first sensor array 6 by the ST1 pulse and the ST2 pulse. Each pixel is accumulated for each pixel. Reference numeral 110 denotes a second charge storage unit, which stores charges in the ON and OFF periods of the second sensor array 106 in each pixel unit by the ST1 pulse and the ST2 pulse, similarly to the first charge storage unit 109. . Reference numeral 111 is a first charge transfer gate such as a CCD, and the first charge storage unit 10
The charges accumulated in 9 are transferred in parallel to the charge transfer means described later, for example, CCD by SH pulse. 1
Reference numeral 13 denotes a first charge transfer unit, which has a ring-shaped structure partially or wholly, and sequentially adds charges during the ON and OFF periods of the first charge storage unit 109 as the charges circulate. . A ring CC is formed where this circulating portion is formed.
D113b and linear CC for the part that does not constitute the circulation part
D113a. Reference numeral 112 denotes a second charge transfer gate, which is similar to the first charge transfer gate 111. 114
Is the second charge transfer means, and the first charge transfer means 11
Same as 3.

Reference numeral 115 denotes a first initialization means, which is a CCD
The charge of the first charge transfer unit 113 is rejected by the CLR pulse to perform initialization. Reference numeral 117 denotes a first skim means for discharging a certain amount of charges. 118 is a similar second skim means. Reference numeral 119 denotes a first SKOS1 signal output unit for determining whether to reject a certain amount of charges, and reads out the amount of charges in the first charge transfer unit 113 while being damaged and leaving charges. It is a thing. 120
Is a second output means of the similar SKOS2 signal. 12
An output unit 1 sequentially reads out the charges in the first charge transfer unit 113 and outputs them as an OS1 signal. Similarly, 122 is an output means for outputting the OS2 signal from the second charge transfer means 114. Reference numeral 123 is a first comparator that determines whether to perform a stem operation from the SKOS1 signal. Similarly, 124 is a second comparator based on the SKOS2 signal. Further, reference numeral 125 is a control unit including a CPU that performs calculations necessary for overall control and distance measurement.

Further, the present applicant has proposed a distance measuring device in which the storage frequency of the distance measuring device once is changed by changing the driving frequency of the skim CCD sensor. Generally, when the driving (transfer) frequency of the CCD is low, the charge transfer efficiency is good, and when the driving (transfer) frequency is high, the charge transfer efficiency is poor. In the distance measuring device according to the above proposal, the skim CCD sensor is first driven at a low frequency with good charge transfer efficiency of the CCD, and when the sensor output or the like is about to be saturated by external light or the like, the driving frequency of the skim CCD sensor is increased. Therefore, the one-time accumulation time is set to be short.

By the way, in recent years, some cameras and the like have a video mode (for example, servo AF) in which distance measurement is continuously repeated. Next, the operation when performing continuous distance measurement with the distance measuring device according to the above proposal will be described with reference to the flowchart of FIG. The distance measuring device is controlled by the CPU. First, in step S501, it is determined whether or not a switch for instructing continuous distance measurement is turned on. If the switch is off here, nothing is done and the process ends. When the switch is on, the counter N for counting the number of continuous distance measurement is reset to 0 in step S502. Next, in step S503, it is determined whether or not the switch for instructing continuous distance measurement is still on. If the switch is off here, the distance measuring operation is ended, and if the switch is on, distance measuring is started in step S504 as described later. When the distance measurement is completed, the continuous distance measurement number counter N is incremented by 1 in step S505 to count up, then the process proceeds to step S603, and steps S503 to S505 are repeated until the switch is turned off.

FIG. 6 is a flow chart for explaining the distance measurement in step S504 in FIG. 5, and shows the operation when the active distance measurement is performed by the distance measuring device. First, in step S601, the light emitting element is switched to the normal output mode in which the light receiving signals at the light emission on timing and the light emission off timing are output as they are in the non-light emitting state. Next, in step S602, the driving frequency of the skim CCD sensor is set to an initial value (for example, 500 kHz), and in step S603, the electronic shutter opening time of the skim CCD sensor is set to an initial value (for example, 50 μS).

Next, in step S604, for example, A /
Using a D converter, etc., a skimmed CCD by one time accumulation
By detecting how much the sensor output is,
Determine the amount of external light component. In step S605, it is determined whether the amount of the external light component obtained in step S604 is larger or smaller than a preset predetermined value. Here, when the amount of the external light component is smaller than the predetermined value, it is determined that the output of the skim CCD sensor is not saturated by the external light component, the process proceeds to step S606, and the light emitting element is turned on / off.
After turning off, the original distance measurement operation is performed, and after the distance measurement value is obtained, the operation ends.

If the amount of the external light component is larger than the predetermined value in step S605, it is determined that the output of the skim CCD sensor is saturated with the external light component, and the process proceeds to step S607. In step S607, the skim C
The drive frequency of the CD sensor is the initial value (here, 500k
Hz), and if the initial value remains unchanged, the skim CCD drive frequency is set to double (here, 1 MHz) in order to shorten the accumulation time once in step S608, and the process proceeds to step S604. .

If the driving frequency of the skim CCD sensor is not the initial value in step S607, step S609
Then, it is determined whether the electronic shutter opening time is the initial value (here, 50 μS). If the electronic shutter open time remains at the initial value, the electronic shutter open time is set to 1/2 (here, 25 μS) in step S610 and the process proceeds to step S604 in order to further shorten the one-time accumulation time. To do.

If the electronic shutter open time is not the initial value in step S609, the amount of external light cannot be controlled (that is, the output of the skim CCD sensor is saturated), and accurate distance measurement cannot be expected. , Distance measurement is impossible and the operation ends.

On the other hand, a multi-point distance measuring device using a distance measuring device for controlling the amount of external light (electronic shutter control, skim CCD driving frequency switching, etc.) like the above distance measuring device will be described with reference to FIGS. To do. FIG. 8 shows a photographing screen of the multi-point distance measuring device mounted on the camera and points for distance measurement. In the figure, C (center of the drawing), L (left of screen), R (right of screen) are distance measuring points,
A light projecting means including a light emitting element and a light receiving means including a skim CCD sensor are provided corresponding to each point.

FIG. 7 is a flow chart for explaining the operation when the distance measuring points shown in FIG. 8 are successively measured.
In the figure, first, in step S701, the point C, which is the center of the screen, is measured. Next, in step S702, the R point on the right side of the screen is measured. Next in step S70
In step 3, the distance to the L point on the left side of the screen is measured. Then, in step S704, the data of the distance measuring point that outputs the closest distance data among the distance measuring points C, R, and L is set as the distance data, and the distance measuring operation ends. Where C, R, L
The distance is operated by the light projecting means and the light receiving means provided corresponding to the respective points in accordance with the flowchart of FIG.

Here, the continuous distance measurement of FIG. 5 is effective when a moving object or the like is an object for distance measurement, or if the time required for one distance measurement is long, continuous distance measurement is possible. The distance measuring operation cannot follow the movement of the moving object, and the reliability of the distance measuring result is lost. In order to solve this problem, the present applicant has disclosed in Japanese Patent Laid-Open No. 6-134902 that signal amount control (auto gain control or auto power control, etc.) performed for each distance measurement is performed only for the first distance measurement, and for the second distance measurement. From the second distance measurement, the signal amount control value determined in the first time is used for control, and the signal amount control during the second and subsequent distance measurements is omitted, thereby reducing the second and subsequent distance measurement times. I am trying.

[0016]

However, in the proposal of Japanese Patent Application No. 6-134902 mentioned above, although the signal amount control is described, especially in an active distance measuring device or the like, external light removal or The time required for removing the external light or controlling the external light amount when performing the external light amount control is not considered. Furthermore, although it is very effective for shortening the distance measurement time during continuous distance measurement, in the case of performing the external light removal or the external light amount control for each distance measurement by the multipoint distance measuring device described in FIGS. The time required for removing external light or controlling the amount of external light is not taken into consideration, and it does not lead to a reduction in the distance measurement time at the time of multi-point distance measurement.

It is an object of the present invention to shorten the distance measurement time by considering the time required for the external light amount control when performing continuous distance measurement or multi-point distance measurement.

[0018]

According to a first aspect of the present invention, a light projecting means for projecting signal light onto a distance measuring object and a light receiving means for receiving reflected light of the signal light from the distance measuring object. Storage transfer means for storing and transferring the signal from the light receiving means, comparing means for comparing the storage amount of the signal in the storage transferring means with a predetermined value, and the storage transfer based on the comparison result of the comparing means. In the distance measuring device having a control means for controlling the accumulation time of the signal in the means and a distance calculation means for calculating the distance to the object to be measured by the accumulated and transferred signals, the control means is continuous. When performing distance measurement, the accumulation time is controlled based on the comparison result at the first distance measurement and the accumulation time is stored, and the stored accumulation time is used at the second and subsequent distance measurements. And to perform the control.

According to a second aspect of the present invention, light receiving means for receiving signal light from a plurality of distance measuring points, storage transfer means for storing and transferring each signal from the light receiving means, and the storage transfer means. Comparing means for comparing the accumulated amount of the signal with a predetermined value, control means for controlling the accumulation time of the signal in the accumulation transfer means based on the comparison result of the comparison means, and the accumulated and transferred signals. In a multipoint distance device having a distance calculating means for calculating a distance to a distance measuring point, the control means, when distance measuring a plurality of distance measuring points in time series, determines a predetermined distance from the plurality of distance measuring points. At the time of distance measurement at the distance measuring point, the accumulation time is controlled based on the comparison result, and the accumulation time is stored.
At the time of distance measurement at other distance measuring points, control is performed using the stored accumulation time.

[0020]

According to the invention of claim 1, when performing continuous distance measurement, the second and subsequent distance measurements are performed using the accumulation time as the external light amount control value determined at the time of the first distance measurement. So
The total distance measurement time can be shortened.

According to the second aspect of the present invention, in the multi-point distance measuring device mounted on the camera or the like, the accumulation time as the external light amount control value determined at the time of measuring the distance to a predetermined distance measuring point such as the central distance measuring point. Since the distances to other distance measuring points are measured using, the entire distance measuring time can be shortened.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The configuration of the distance measuring device according to the first embodiment is similar to that shown in FIG.
It is assumed that the distance measuring device uses a D sensor. Also,
The outline operation of the continuous distance measurement is similar to that of the flowchart of FIG.

In this embodiment, step S in FIG.
Since the contents of the portion 504 (subroutine) are different from those in FIG. 6, that portion will be described with reference to FIG. First, in step S101, it is determined whether or not the continuous distance measurement counter N = 0 (that is, whether or not it is the first distance measurement). If N = 0 here, in step S102, the light emitting element is switched to the normal output mode in which the light receiving signals at the light emission on timing and the light emission off timing are output as they are in the non-light projecting state. Next, in step S103, the driving frequency of the skim CCD sensor is set to an initial value (for example, 500 kHz), and in step S104, the electronic shutter opening time of the skim CCD sensor is set to an initial value (for example, 50 μS).

Next, in step S105, for example, A
By using the / D converter, etc.
The amount of the external light component is measured by detecting the output of the D sensor. In step S106,
It is determined whether the amount of the external light component obtained in step S105 is larger or smaller than a preset predetermined value. Here, when the amount of the external light component is smaller than the predetermined value, the skim CC
Assuming that the D sensor output is not saturated by the external light component, the process proceeds to step S107, and the external light amount control value (that is, the set value of the driving frequency of the skim CCD sensor and the electronic shutter open time of the skim CCD sensor) is stored. In step S108, the light emitting element is turned on / off to perform the original distance measuring operation, and after obtaining the control value, the operation is ended.

When the amount of the external light component is larger than the predetermined value in step S106, it is determined that the output of the skim CCD sensor is saturated with the external light component, and the process proceeds to step S109. In step S109, the skim C
The drive frequency of the CD sensor is the initial value (here, 500k
Hz), and if the initial value remains unchanged, the skim CCD drive frequency is set to double (here, 1 MHz) in step S110 to shorten the accumulation time once, and the process proceeds to step S105.

If the driving frequency of the skim CCD sensor is not the initial value in step S109, step S111
Then, it is determined whether the electronic shutter opening time is the initial value (here, 50 μS). If the electronic shutter open time remains at the initial value, the electronic shutter open time is set to 1/2 (here, 25 μS) in step S112 in order to further shorten the one-time accumulation time, and the process proceeds to step S105. To do.

If the electronic shutter open time is not the initial value in step S111, the amount of outside light cannot be controlled (that is, the output of the skim CCD sensor is saturated), and accurate distance measurement cannot be expected. The distance measurement is deemed impossible and the operation ends.

When it is determined in step S101 that the continuous control counter N ≠ 0 (that is, the second and subsequent distance measurement), the process proceeds to step S114, and the above step S10 is performed.
The external light amount control value at the first distance measurement stored in step 7 (that is, the driving frequency of the skim CCD sensor and the skim CC
After setting the electronic shutter open time of the D sensor), the light emitting element is turned on / off in step S108 to perform the original distance measuring operation to obtain the distance measuring value, and then the operation ends.

It should be noted here that during the second and subsequent distance measurements, the step of determining the outside light amount control value from step S101 to step S107 and step S109 to step S113 is skipped. .

Although the distance measuring device using the skim CCD sensor has been described here, a distance measuring device which also controls the amount of external light can be operated in the same manner as this embodiment. Good.

(Second Embodiment) A distance measuring device according to the present embodiment is a multi-point distance measuring device mounted on a camera or the like.
The distance measurement points of C, L, and R described in 1 above are measured. The structure of the distance measuring device is the same as that of the conventional multi-point distance measuring device, for example, the structure shown in FIG. Further, the general operation of multi-point distance measurement is similar to that of the flowchart of FIG.
Further, each distance measurement (subroutine) of C, R, and L is operated according to the flowchart of FIG. 2 by each light projecting means and each light receiving means provided corresponding to each point.

First, in step S201, it is determined whether or not the distance measuring point for multi-point distance measuring is the center (C) of the screen. If the distance measuring point is at the center of the screen (C), then in step S202, the light emitting element is in a non-light projecting state, and the normal output mode in which the light receiving signals at the light emission on timing and the light emission off timing are directly output is switched. Next, in step S203, the driving frequency of the skim CCD sensor is set to an initial value (for example, 500).
kHz), and the skim CCD is set in step S204.
The electronic shutter open time of the sensor is set to the initial value (for example, 50
μS).

Next, in step S205, for example, A
By using the / D converter, etc.
The amount of the external light component is measured by detecting the output of the D sensor. In step S206,
It is determined whether the amount of the external light component obtained in step S205 is larger or smaller than a preset predetermined value. Here, when the amount of the external light component is smaller than the predetermined value, the skim CC
Assuming that the D sensor output is not saturated by the external light component, the process proceeds to step S207 and the external light amount control value (that is, the set value of the skim CCD sensor drive frequency and the skim CCD sensor electronic shutter open time) is stored. In step S208, the light emitting element is turned on / off to perform the original distance measuring operation, obtain the control value, and then the operation is ended.

When the amount of the external light component is larger than the predetermined value in step S206, it is determined that the output of the skim CCD sensor is saturated with the external light component, and the process proceeds to step S209. In step S209, the skim C
The drive frequency of the CD sensor is the initial value (here, 500k
If the initial value remains unchanged, the skim CCD drive frequency is doubled (here, 1 MHz) in order to shorten the storage time once in step S110, and the process proceeds to step S205.

If the driving frequency of the skim CCD sensor is not the initial value in step S209, step S211
Then, it is determined whether the electronic shutter opening time is the initial value (here, 50 μS). If the electronic shutter open time remains at the initial value, the electronic shutter open time is set to 1/2 (here, 25 μS) in step S212 in order to further shorten the one-time accumulation time, and the process proceeds to step S205. To do.

If the electronic shutter open time is not the initial value in step S211, it is impossible to control the amount of external light (that is, the output of the skim CCD sensor is saturated), and accurate distance measurement cannot be expected. , Distance measurement is impossible and the operation ends.

In step S201, if the distance measuring point for multi-point distance measurement is not the screen center (C), the process proceeds to step S214, and the outside light amount control value (that is, the control value of the outside light at the time of the screen center (C) distance measurement stored in step S207 is used. After setting the driving frequency of the skim CCD sensor and the set value of the electronic shutter opening time of the skim CCD sensor, the light emitting element is turned on / off in step S208 to perform the original distance measurement operation, and after the distance measurement value is obtained. , Ends the operation.

It should be noted that, when the distance measuring point is other than the center of the screen, the step of determining the outside light amount control value from step S201 to step S207 and step S209 to step S213 is skipped. .

Now, description will be given of the case where the multi-point distance measuring apparatus according to this embodiment measures the distance to the object to be measured in FIGS. 3 (a) to 3 (c). In FIG. 3A, a daytime landscape is being distance-measured, and the distance-measurement points C, R, and L have the same outside light luminance. When the distance measuring operation is advanced according to FIG. 7 or FIG. 2, the distance measuring order is C → R → L as described with reference to FIG. 7, but in the present invention, the amount of outside light is as shown in FIG. The control value is determined by the distance measuring point C, and the external light amount control values of the distance measuring points R and L are set to be the same as the value of the distance measuring point C. However, the distance measuring point C,
Since the external light intensities of R and L are equal, it is possible to prevent saturation of the output of the skim CCD sensor due to external light at each of the distance measuring points C, R, and L.

In FIG. 3B, the distance between a person positioned on the right side of the screen during the day is measured, and the outside light brightness at the distance measuring point R is darker than the outside light brightness at the distance measuring points C and L. . Also in this case, the external light amount control value is determined by the distance measuring point C as shown in FIG. 2, and the external light amount control values of the distance measuring points R and L are set to be the same as the value of the distance measuring point C. Since the external light brightness at the distance measuring point R is darker than the external light brightness at the distance measuring points C and L, it is possible to prevent saturation of the output of the skim CCD sensor due to the external light at both the distance measuring points C, R, and L.

FIG. 3C shows that a person located at the center of the screen during the day is being measured, and the external light brightness at the distance measuring point C is darker than the external light brightness at the distance measuring points R and L. . Also in this case, the external light amount control value is determined by the distance measuring point C as shown in FIG. 2, and the external light amount control values of the distance measuring points R and L are set to be the same as the value of the distance measuring point C. For this reason, it is conceivable that the distance measuring points R and L cannot sufficiently block the external light and thus cannot measure the distance. However, the object to be measured is the person at the center of the screen, and the distance can be measured by the distance measuring point C where the amount of external light is sufficiently controlled.

Although the distance measuring device using the skim CCD sensor has been described here, a distance measuring device which also controls the amount of external light can be operated in the same manner as this embodiment. Good. Further, regarding the external light signal amount control of the passive distance measurement in the multi-point passive distance measuring device, the distance measurement of other distance measuring points may be performed with the external light signal amount control value determined at the time of distance measurement in the center of the screen. Good.

[0043]

As described above, according to the invention of claim 1,
When performing continuous distance, the second and subsequent distance measurements can be shortened by performing the second and subsequent distance measurements with the external light amount control value determined during the first distance measurement. , It is possible to sufficiently follow up even if a moving distance measuring object is continuously measured.

According to the second aspect of the present invention, a multipoint distance measuring device mounted on a camera or the like is used to measure the distance to other distance measuring points by the outside light amount control value determined at the time of distance measuring at the center of the screen or the like. By doing so, it is possible to shorten the distance measurement time of other distance measurement points and solve the problem that the release time lag in a camera or the like having a multi-point distance measurement function becomes long.

[Brief description of drawings]

FIG. 1 is a flowchart explaining a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a distance measurement screen for explaining a second embodiment of the present invention.

FIG. 4 is a configuration diagram of a distance measuring device using a conventional skim CCD sensor.

FIG. 5 is a flowchart illustrating an outline of a conventional continuous distance measuring operation.

FIG. 6 is a flowchart illustrating a conventional distance measuring operation.

FIG. 7 is a flowchart illustrating an outline of a distance measuring operation of a conventional multipoint distance measuring device.

FIG. 8 is a configuration diagram showing distance measuring points of a multipoint distance measuring device mounted on a camera.

[Explanation of symbols]

 104 Light-Emitting Element 106, 105 Sensor Array 109, 110 Charge Accumulating Section 111, 112 Charge Transfer Gate 113, 114 Charge Transfer Means 125 Control Section

Claims (6)

[Claims] 1. A light projecting means for projecting signal light onto an object to be measured, a light receiving means for receiving reflected light of the signal light from the object to be measured, and storing and transferring signals from the light receiving means. Storage and transfer means, comparison means for comparing the storage amount of the signal in the storage and transfer means with a predetermined value, and control means for controlling the storage time of the signal in the storage and transfer means based on the comparison result of the comparison means. And a distance calculating device for calculating a distance to the object to be measured by the accumulated and transferred signals, wherein the control device, when performing continuous distance measurement, at the time of the first distance measurement. The storage time is controlled based on the comparison result, the storage time is stored, and the stored storage time is used for the second and subsequent distance measurements. Distance device. 2. A light receiving means for receiving signal light from a plurality of distance measuring points, a storage transfer means for storing and transferring each signal from the light receiving means, and a storage amount of the signal in the storage transfer means. Is compared with a predetermined value, control means for controlling the accumulation time of the signal in the accumulation transfer means based on the comparison result of the comparison means, and the distance to the distance measuring point by the accumulated and transferred signals. In a multipoint distance device having a distance calculating means for calculating the distance, the control means measures the distance of a predetermined distance measuring point among the plurality of distance measuring points when the distance measuring points are measured in time series. The storage time is sometimes controlled on the basis of the comparison result and the storage time is stored, and the stored storage time is used for the distance measurement of another focus detection point. Distance unit. 3. The distance measuring device according to claim 2, wherein the predetermined distance measuring point is a substantially central distance measuring point. 4. The distance measuring device according to claim 1, wherein the light receiving means includes a cyclic shift register. 5. The distance measuring apparatus according to claim 4, wherein the control means changes the storage time by controlling a drive frequency of the cyclic shift register. 6. The distance measuring device according to claim 4, wherein the control means is configured to change the accumulation time by controlling an electronic shutter time of the cyclic shift register.