JP2024086480A - Photodetection system, imaging apparatus, and control method - Google Patents

Abstract

To provide a photodetection system that can obtain high-quality images while reducing power consumption.SOLUTION: A photodetection system 1000 has: a first photodetection unit 200 in which a plurality of first photoelectric conversion units each including a photodiode accumulating electric charges and converting them into voltage values are arranged on a two-dimensional plane; a second photodetection unit 300 in which a plurality of second photoelectric conversion units each including an avalanche photodiode converting incident photons into pulses are arranged on the two-dimensional plane; and a control unit 400 that causes either one of the first photodetection unit or the second photodetection unit to acquire an image of a subject based on information on the quantity of light from the subject acquired by at least either one of the first photodetection unit or the second photodetection unit.SELECTED DRAWING: Figure 1

Description

The present invention relates to an optical detection system.

There are known imaging elements that accumulate electric charge and convert it into a voltage value, such as CMOS (Complementary Metal-Oxide-Semiconductor) sensors and CCD (Charge Coupled Device) sensors. These are used in digital cameras, video cameras, etc.

In the method of accumulating electric charge and converting it into a voltage value, it is known that random noise occurs when amplifying the voltage, resulting in a decrease in the signal-to-noise ratio.

Meanwhile, in recent years, photon-counting imaging elements have been proposed that can measure the number of incident photons and handle the incident light as a digital value. With photon-counting imaging elements, it is possible to directly measure the number of incident photons, so it is expected that random noise will not occur and the S/N ratio will be improved. Photon-counting imaging elements are also called SPAD (Single Photon Avalahche Diode) sensors.

Patent document 1 discloses a SPAD sensor for distance measurement.

JP 2014-81253 A

In a SPAD sensor, a high electric field equal to or greater than the breakdown voltage must be applied to operate the photodiode, resulting in a problem of high power consumption. The present invention provides a light detection system that can obtain high-quality images while suppressing power consumption.

The photodetection system according to one aspect of the present invention is characterized by having a first photodetector having a plurality of first photoelectric conversion units arranged in a two-dimensional plane, the first photodetector having a photodiode that accumulates electric charge and converts it into a voltage value, a second photodetector having a plurality of second photoelectric conversion units arranged in a two-dimensional plane, the second photodetector having an avalanche photodiode that converts incident photons into pulses, and a control unit that causes either the first photodetector or the second photodetector to acquire an image of the subject based on light quantity information of the subject.

Other objects and features of the present invention are described in the following examples.

The present invention provides an optical detection system that can obtain high-quality images while reducing power consumption.

FIG. 1 is a configuration diagram of a light detection system according to a first embodiment. 4 is a flowchart showing the operation of the light detection system in the first embodiment. 5A to 5C are configuration diagrams of a pixel region of a second light detection unit in each embodiment. FIG. 11 is a configuration diagram of a light detection system according to a second embodiment. 10 is a flowchart showing the operation of the light detection system in the second embodiment. FIG. 1 is an external view of an imaging device equipped with a light detection system according to each embodiment.

The following describes in detail an embodiment of the present invention with reference to the drawings. In each drawing, the same components are given the same reference symbols, and duplicate descriptions are omitted.

First Embodiment
First, an outline of the light detection system 1000 in the first embodiment will be described with reference to FIG. 1. FIG. 1 is a configuration diagram of the light detection system 1000 in this embodiment. The light detection system 1000 in this embodiment has a first light detection unit 200 and a second light detection unit 300. In the first light detection unit 200, a plurality of first photoelectric conversion units each having a photodiode that accumulates electric charge and converts it into a voltage are arranged in a two-dimensional plane. In the second light detection unit, a plurality of second photoelectric conversion units each having an avalanche photodiode that converts incident photons into pulses are arranged in a two-dimensional plane. The light detection system 1000 in this embodiment acquires light (image) of the subject 100 using the first light detection unit 200 or the second light detection unit 300. In the light detection system 1000 shown in FIG. 1, the first light detection unit 200 and the second light detection unit 300 may be fixed to a fixed part such as the ground, or may be attached to a flying object such as a drone to acquire light of the subject 100 in a flying state.

The control unit 400 controls the shooting conditions of the first light detection unit 200 and the second light detection unit 300. The calculation processing unit 500 performs image processing on the light acquired by the first light detection unit 200 or the second light detection unit 300. The processed image is sent to the storage unit 600 or the display unit 700, which serve as image receiving units. A detailed processing flow will be described later.

The first light detection unit 200 has an imaging optical system 201 and a CMOS sensor 202. Note that a CCD sensor may be used instead of the CMOS sensor 202. The second light detection unit 300 has an imaging optical system 301 and a SPAD sensor 302. The substrate of each sensor is provided with a color filter array in a Bayer arrangement of, for example, R (red), G (green), and B (blue). Note that light may be acquired using a monochrome filter instead of a color filter.

The arithmetic processing unit 500 has a threshold determination unit (determination unit) 501 that determines the amount of light (light amount information) of the subject 100 acquired by at least one of the first light detection unit 200 or the second light detection unit 300. Furthermore, the arithmetic processing unit 500 has an image information calculation unit 502 that calculates the light acquired by the CMOS sensor 202 or the SPAD sensor 302 to obtain image information. The image information calculation unit 502 performs image processing such as color correction processing, AE (Auto Exposure) processing, white balance processing, and optical shading correction processing on the light acquired by the CMOS sensor 202 or the SPAD sensor 302. The control unit 400 has a light detection unit selection unit 401 for selecting one of the first light detection unit 200 or the second light detection unit 300, and a shooting condition control unit 402 that controls the shooting conditions of the first light detection unit 200 and the second light detection unit 300. The control unit 400 selects either the first light detection unit 200 or the second light detection unit 300 based on the light amount information of the subject 100, and causes the selected light detection unit to acquire the light (image) of the subject 100. The shooting condition control unit 402 controls shooting conditions such as the F-number of the imaging optical system 201 and the imaging optical system 301, the position of the focus group, and the shutter speed of the CMOS sensor 202 and the SPAD sensor 302. The control unit 400 is configured with, for example, a CPU (Central Processing Unit) and peripheral circuits.

The display unit (image receiving unit) 700 displays the image acquired by the first light detection unit 200 or the second light detection unit 300. The memory unit 600 (image receiving unit) has an image information memory unit 601 that stores image information acquired by the first light detection unit 200 or the second light detection unit 300, and an image capture information memory unit 602 that stores the image capture conditions used for image capture. The image capture time acquisition unit 900 acquires the time when the image was captured.

The SPAD sensor 302 has a large S/N ratio, i.e., a high-quality image can be obtained even when the amount of light on the subject is small. On the other hand, the CMOS sensor 202 can obtain a high-quality image by suppressing the S/N ratio when the amount of light on the subject is relatively large, while suppressing power consumption compared to the SPAD sensor 302. Therefore, in the light detection system 1000 of this embodiment, when the amount of light on the subject 100 is small, the second light detection unit 300 having the SPAD sensor 302 acquires the light of the subject 100. When the amount of light on the subject 100 is large, the first light detection unit 200 having the CMOS sensor 202 acquires the light of the subject 100. In this way, in the light detection system 1000 of this embodiment, the control unit 400 selects either the first light detection unit 200 or the second light detection unit 300 as the light detection unit that acquires the light of the subject 100 according to the light amount information of the subject 100. This makes it possible to obtain a high-quality image while suppressing power consumption regardless of the shooting environment. The amount of light on the subject 100 is determined by the threshold determination unit 501. The threshold determination unit 501 determines the amount of light from the subject 100 based on the sum of the luminance values of a part or all of a predetermined area of an image acquired by the CMOS sensor 202 or the SPAD sensor 302. The threshold determination unit 501 may determine the amount of light from the subject 100 based on the average value (average luminance value) of the luminance values of a part or all of the areas of an image acquired by the CMOS sensor 202 or the SPAD sensor 302. By using the luminance value acquired by the CMOS sensor 202 or the SPAD sensor 302 for the determination, it is possible to reduce the number of measurement systems that measure the luminance values and suppress power consumption.

The threshold determination unit 501 may also determine the amount of light on the subject 100 only at night, based on the shooting time acquired by the shooting time acquisition unit 800. In this case, the light on the subject 100 is acquired only by the CMOS sensor 202 during the day. This allows power consumption to be reduced by performing the determination by the threshold determination unit 501 only at night, and always using the CMOS sensor 202, which consumes less power, during the day when the amount of light on the subject 100 is relatively high.

In this embodiment, the selection of the first light detection unit 200 or the second light detection unit 300 is performed based on the judgment result by the threshold judgment unit 501, but this embodiment is not limited to this. The control unit 400 may select either the first light detection unit 200 or the second light detection unit 300 based only on the shooting time acquired by the shooting time acquisition unit 800 without judgment by the threshold judgment unit 501. In this case, for example, during the day, the light of the subject 100 is acquired only by the CMOS sensor 202, and at night, the light of the subject 100 is acquired only by the SPAD sensor 302. By selecting based only on the shooting time, the threshold judgment unit 501 can be eliminated and power consumption can be reduced.

The imaging optical system 201 and the imaging optical system 301 may be a common optical system. In this case, for example, a switching means for switching between the CMOS sensor 202 and the SPAD sensor 302 in a turret type is used to acquire the light from the subject 100 while switching.

Next, referring to FIG. 3, an example of the configuration of the SPAD sensor 302 used in this embodiment will be described. FIG. 3 is an example of an equivalent circuit diagram of the SPAD sensor 302. For simplification, FIG. 3 shows four pixel units T103 and five signal generation units T104 arranged from the 0th row to the 2nd row and the 0th column to the 2nd column.

Each of the multiple pixel units T103 is a photoelectric conversion unit and includes an avalanche photodiode (hereinafter, APD) T201, a quench element T202, a signal processing circuit T211, and a selection circuit T212.

When light is incident on the APDT201, a charge pair is generated by photoelectric conversion in response to the incident light. A voltage VL is supplied to the anode of the APDT201. A voltage VH higher than the voltage VL supplied to the anode is supplied to the cathode of the APDT201. A reverse bias voltage is supplied to the anode and cathode of the APDT201 so that the APDT201 performs avalanche multiplication. By supplying such a voltage, the charge generated by the incident light undergoes avalanche multiplication, generating an avalanche current. When a reverse bias voltage is supplied, there are two operating modes: a Geiger mode in which the potential difference between the anode and cathode is greater than the breakdown voltage, and a linear mode in which the potential difference between the anode and cathode is close to or less than the breakdown voltage. An APD operated in the Geiger mode is called a SPAD. The quench element T202 is connected between a power supply that supplies the voltage VH and the cathode of the APDT201. The quench element T202 has a function of replacing the change in avalanche current generated in the APDT201 with a voltage signal. The quench element T202 functions as a load circuit (quench circuit) during signal multiplication by avalanche multiplication, and suppresses the voltage supplied to the APDT201 to suppress avalanche multiplication. The signal processing circuit T211 has a function of counting the potential change of the cathode of the APDT201 obtained during photon detection. This function can be realized, for example, by the signal processing circuit T211 being provided with a counter circuit that counts pulses generated by the potential change of the cathode. This allows the signal processing circuit T211 to output a count value corresponding to the number of photons incident on the APDT201. The signal processing circuit T211 initializes the counter circuit in response to a control signal input via the control line T213. The selection circuit T212 includes, for example, a switch that controls electrical connection and non-connection, a buffer circuit for outputting a signal, and the like. In this embodiment, the pixel unit T103 has a function of outputting the count value of photons incident on the APDT201 as a digital signal, but is not limited to this. The signal processing circuit T211 may include a time-to-digital conversion circuit and a memory. The pixel unit T103 may be a pixel for measuring the time when light arrives and the amount of light.

Each of the multiple signal generating units T104 includes a signal generating circuit T215 and a selection circuit T212. The signal generating circuit T215 is configured to output a digital signal having a predetermined n-bit (n is a natural number) digital value. The signal generating circuit T215 performs processes related to signal generation, such as initialization, in response to a control signal input via a control line T213. These signals are output to the outside via a signal output circuit.

Next, the operation of the light detection system 1000 in this embodiment will be described. Figure 2 is a flowchart showing the operation of the light detection system 1000 in this embodiment.

First, in step S101, an image of the subject 100 is acquired using the first light detection unit 200. Since the CMOS sensor 202 (or CCD sensor) consumes less power than the SPAD sensor 302, power consumption can be reduced by acquiring an image of the subject 100 using the first light detection unit 200.

In step S102, the threshold determination unit 501 determines whether the luminance value of the image of the subject 100 acquired in step S101 is equal to or greater than a threshold value. Here, the threshold value is a luminance value sufficient to acquire a high-quality image. The luminance value is the input value of light to a pixel, and in the case of 8 bits, the maximum luminance value is 255. For example, when the sum of the luminance values of each image is used as the threshold value, if the threshold value is about one-tenth of the sum of the maximum luminance values of each pixel, an image of sufficiently high quality can be acquired by using the CMOS sensor 202 when the threshold value is equal to or greater than this value. Preferably, the threshold value is about one-hundredth of the sum of the maximum luminance values of each image. Furthermore, when the average luminance value of the image is used as the threshold value, a threshold value of about one-tenth, preferably about one-hundredth of the maximum luminance value of the image can be used.

If the brightness value of the image is below the threshold, the flow proceeds to step S103. In step S103, an image of the subject 100 is acquired using the second light detection unit 300.

In step S104, the calculation processing unit 500 transmits the image acquired in step S101 or step S103 to the image information storage unit 601.

In step S105, the image information storage unit 601 receives and records the image sent in step S104.

In step S106, the control unit 400 determines whether the shooting mode is a video mode.

If the shooting mode is not the video mode (i.e., if the shooting mode is the still image mode), the control unit 400 ends the process. If the shooting mode is the video mode, the flow proceeds to step S107. In step S107, an image of the subject 100 is acquired using the light detection unit that acquired the image transmitted in step S104. In this embodiment, an image is acquired using the first light detection unit 200 in step S101, and a threshold determination is performed in step S102 using the luminance value of the image. However, this embodiment is not limited to this. In the threshold determination in step S102, an image acquired by the second light detection unit 300 may be used, or images may be acquired by both the first light detection unit 200 and the second light detection unit 300.

In addition, from the viewpoint of reducing power consumption, it is preferable to obtain the first image using the first light detection unit 200, as in this embodiment.

In addition, in this embodiment, the threshold determination by the threshold determination unit 501 in step S102 is performed only once during the shooting operation from the start to the end of shooting. However, when the shooting mode is a video mode, the threshold determination by the threshold determination unit 501 in step S102 may be performed for each frame using the image acquired by the light detection unit currently used for shooting. However, from the viewpoint of suppressing power consumption, it is preferable to perform the threshold determination in step S102 for each multiple frames at a certain time interval. By performing the determination for each multiple frames, power consumption can be suppressed compared to the case where the threshold determination is always performed for each frame. For example, during the day, since the amount of light is expected to be large, the threshold determination may be performed at a longer time interval such as every 1 hour or every 2 hours. Also, at night when the amount of light is considered to be small, the amount of light may temporarily increase due to the lights of automobiles or ships, and the luminance value of the image may exceed the threshold, so it is preferable to frequently perform the threshold determination at short time intervals such as every 10 minutes or every 5 minutes. Of course, the time interval setting for the threshold determination is not limited to these, and should be set appropriately according to the shooting environment.

The optical detection system 1000 may also store data in a memory unit provided in an external device, such as a cloud computing device, via communication.

Second Embodiment
Next, the light detection system 1000a in the second embodiment will be described. FIG. 4 is a block diagram of the light detection system 1000a in the second embodiment. The light detection system 1000a in the second embodiment is different from the light detection system 1000 in the first embodiment in that it has an illuminance determination unit 1100a and that the calculation processing unit 500a does not have a threshold determination unit 501. Since the other configurations of the light detection system 1000a in this embodiment are similar to those of the light detection system 1000 in the first embodiment, the description thereof will be omitted. In this embodiment, a CCD sensor is used for the first light detection unit 200a, but a CMOS sensor may be used. In addition, the light detection system 1000a in this embodiment may have a shooting time acquisition unit 800 as in the first embodiment.

The illuminance determination unit 1100a has an illuminance acquisition unit 1101a that acquires the illuminance of the subject 100a, and a threshold determination unit 1102a that determines whether the illuminance is equal to or greater than a threshold. The illuminance acquisition unit 1101a is, for example, a light meter, and measures the illuminance (lux) of the subject 100a. For example, an illuminance of about 1 to 10 lux may be used as the threshold. An illuminance of about 0.1 to 1 lux is preferably used. Of course, the illuminance for threshold determination is not limited to these, and should be set appropriately according to the shooting environment.

The threshold determination unit 1102a uses the illuminance of the subject 100a acquired by the illuminance acquisition unit 1101a for threshold determination. By measuring the illuminance using the illuminance acquisition unit 1101a, the illuminance of the subject 100a can be measured accurately. The illuminance may be measured every time the first light detection unit 200a or the second light detection unit 300a acquires light, may be measured at regular time intervals, or may be measured a specific number of times within a certain period of time.

The threshold determination unit 1102a performs threshold determination using the acquired illuminance and transmits the result to the control unit 400a. If the acquired illuminance is equal to or greater than the threshold, the control unit 400a acquires the light of the subject 100a using the first light detection unit 200a, and if the acquired illuminance is below the threshold, the control unit 400a acquires the light of the subject 100a using the second light detection unit 300a.

The threshold determination unit 1102a may be included in another component such as the control unit 400a, rather than in the illuminance determination unit 1100a.

Next, the operation of the light detection system 1000a in this embodiment will be described. FIG. 5 is a flowchart showing the operation of the light detection system 1000a in this embodiment.

First, in step S201, the illuminance of the subject 100a is acquired using the illuminance acquisition unit 1101a.

In step S202, the threshold determination unit 1102a determines whether the illuminance acquired in step S201 is equal to or greater than the threshold.

If the illuminance is equal to or greater than the threshold, the flow proceeds to step S203. If the illuminance is less than the threshold, the flow proceeds to step S207. In step S203, an image of the subject 100a is acquired using the first light detection unit 200a. In step S207, an image of the subject 100a is acquired using the second light detection unit 300a.

In step S204, the calculation processing unit 500a transmits the image acquired in step S203 or step S207 to the image information storage unit 601a.

In step S205, the image information storage unit 601a receives and records the image sent in step S204.

In step S206, the control unit 400a determines whether the shooting mode is video mode.

If the shooting mode is not the video mode (i.e., if the shooting mode is the still image mode), the control unit 400a ends the process. If the shooting mode is the video mode, the flow returns to step S201, and the illuminance is acquired again.

In this embodiment, when the shooting mode is the video mode, the illuminance is acquired for each frame (S201). However, the acquisition of the illuminance in S201 may be performed for each set of frames at regular time intervals. By acquiring the illuminance for each set of frames at regular time intervals, it is possible to reduce power consumption compared to acquiring the illuminance every time.

Furthermore, the light detection system 1000a may store data in a storage unit provided in an external device, such as a cloud computing device, via communication.
Other Examples
The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

According to each embodiment, it is possible to provide a light detection system that can obtain high-quality images while suppressing power consumption.

Next, an example of a digital still camera (imaging device) using the optical detection system of each embodiment will be described with reference to FIG. 6. FIG. 6 is a diagram showing the configuration of the imaging device 10. The imaging device 10 includes an optical detection system 1000 (1000a) of each embodiment, which includes a camera body 13, an imaging optical system (lens device) 11, and an imaging element (light receiving element) 12 that photoelectrically converts an image formed by the imaging optical system 11. The lens device 11 and the camera body 13 may be integrally configured, or may be detachably configured. The camera body 13 may be a so-called single-lens reflex camera having a quick-turn mirror, or may be a so-called mirrorless camera not having a quick-turn mirror. In this embodiment, since the imaging optical system 11 is shared, the optical detection system 1000 (1000a) acquires the light (image) of the subject while switching between the first optical detection unit 200 (200a) and the second optical detection unit 300 (300a) using a turret-type switching means.

The imaging device 10 of this embodiment is not limited to the digital still camera shown in FIG. 6, but can also be applied to various imaging devices such as broadcast cameras, cameras for silver halide film, and surveillance cameras.

The disclosure of each embodiment includes the following configurations and methods:

(Configuration 1)
a first light detection unit in which a plurality of first photoelectric conversion units each having a photodiode that accumulates electric charge and converts the electric charge into a voltage value are arranged on a two-dimensional plane;
a second photodetector unit in which a plurality of second photoelectric conversion units, each of which has an avalanche photodiode that converts incident photons into a pulse, are arranged on a two-dimensional plane;
and a control unit that causes one of the first light detection unit or the second light detection unit to obtain an image of the subject based on light amount information of the subject.
(Configuration 2)
A determination unit that determines the light amount information,
The control unit is
When the light amount information determined by the determination unit is equal to or less than a threshold value, the second light detection unit is caused to acquire the image of the subject;
The light detection system according to configuration 1, characterized in that, when the light amount information determined by the determination unit exceeds the threshold, the first light detection unit is caused to acquire the image of the subject.
(Configuration 3)
3. The light detection system according to configuration 1 or 2, wherein the light amount information is image information acquired by at least one of the first light detection unit and the second light detection unit.
(Configuration 4)
4. The light detection system according to any one of configurations 1 to 3, wherein the light amount information is image information detected by the first light detection unit.
(Configuration 5)
5. The optical detection system according to claim 3, wherein the image information is a sum of luminance values of a predetermined area of the image.
(Configuration 6)
5. The optical detection system according to claim 3, wherein the image information is an average value of luminance values in a predetermined area of the image.
(Configuration 7)
the determination unit is an illuminance determination unit that obtains an illuminance of the subject,
3. The light detection system according to claim 2, wherein the light amount information is the illuminance acquired by the illuminance determination unit.
(Configuration 8)
8. The light detection system according to claim 2, wherein the determining unit determines the light amount information for each of a plurality of frames.
(Configuration 9)
A photographing time acquisition unit that acquires a photographing time of the subject is further provided,
The control unit is
determining whether or not to perform a determination by the determination unit based on the photographing time acquired by the photographing time acquisition unit;
8. The light detection system according to configuration 2 or 7, wherein when the determination unit does not perform the determination, the first light detection unit is caused to acquire the image of the subject.
(Configuration 10)
10. The optical detection system according to any one of configurations 1 to 9, further comprising an image receiving unit that receives an image acquired by the first optical detection unit or the second optical detection unit.
(Configuration 11)
11. The optical detection system according to claim 10, wherein the image receiving unit is a storage unit that stores the image.
(Configuration 12)
11. The optical detection system according to configuration 10, wherein the image receiving unit is a display unit that displays the image.
(Configuration 13)
a first light detection unit in which a plurality of first photoelectric conversion units each having a photodiode that accumulates electric charge and converts the electric charge into a voltage are arranged on a two-dimensional plane;
a second photodetector unit in which a plurality of second photoelectric conversion units, each of which has an avalanche photodiode that converts incident photons into a pulse, are arranged on a two-dimensional plane;
a photographing time acquisition unit that acquires a photographing time of a subject,
and a control unit that causes one of the first light detection unit or the second light detection unit to acquire an image of the subject based on the shooting time.
(Configuration 14)
An imaging optical system;
and a light detection system according to any one of configurations 1 to 13, which acquires an image formed by the imaging optical system.
(Method 1)
A method for controlling a photodetection system including a first photodetector having a plurality of first photoelectric conversion units arranged in a two-dimensional plane, the first photodetector having a photodiode that accumulates charge and converts the charge into a voltage, and a second photodetector having a plurality of second photoelectric conversion units arranged in the two-dimensional plane, the second photodetector having an avalanche photodiode that converts incident photons into pulses, the method comprising:
acquiring light amount information of a subject;
and causing one of the first light detection unit and the second light detection unit to acquire an image of the subject based on the light amount information.
(Method 2)
A method for controlling a photodetection system including a first photodetector having a plurality of first photoelectric conversion units arranged in a two-dimensional plane, the first photodetector having a photodiode that accumulates charge and converts the charge into a voltage, and a second photodetector having a plurality of second photoelectric conversion units arranged in the two-dimensional plane, the second photodetector having an avalanche photodiode that converts incident photons into pulses, the method comprising:
acquiring a time when the subject was photographed;
and causing one of the first light detection unit and the second light detection unit to acquire an image of the subject based on the shooting time.
(Configuration 15)
A program for causing a computer to execute the method for controlling a light detection system according to the method 1 or 2.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. Parts of the above-described embodiments may be combined as appropriate.

1000 Light detection system 200 First light detection unit 300 Second light detection unit 400 Control unit

Claims (17)

a first light detection unit in which a plurality of first photoelectric conversion units each having a photodiode that accumulates electric charge and converts the electric charge into a voltage value are arranged on a two-dimensional plane;
a second photodetector unit in which a plurality of second photoelectric conversion units, each of which has an avalanche photodiode that converts incident photons into a pulse, are arranged on a two-dimensional plane;
and a control unit that causes one of the first light detection unit or the second light detection unit to obtain an image of the subject based on light amount information of the subject. A determination unit that determines the light amount information,
The control unit is
When the light amount information determined by the determination unit is equal to or less than a threshold value, the second light detection unit is caused to acquire the image of the subject;
2. The light detection system according to claim 1, wherein when the light amount information determined by the determination unit exceeds the threshold value, the first light detection unit is caused to obtain the image of the subject. The light detection system according to claim 1, characterized in that the light quantity information is image information acquired by at least one of the first light detection unit or the second light detection unit. The light detection system according to claim 1, characterized in that the light quantity information is image information detected by the first light detection unit. The optical detection system according to claim 3, characterized in that the image information is a sum of luminance values of a predetermined area of the image. The optical detection system of claim 3, characterized in that the image information is an average value of luminance values in a predetermined area of the image. the determination unit is an illuminance determination unit that obtains an illuminance of the subject,
The light detection system according to claim 2 , wherein the light amount information is the illuminance acquired by the illuminance determining unit. The light detection system according to claim 2, characterized in that the determination unit determines the light quantity information for each of a plurality of frames. A photographing time acquisition unit that acquires a photographing time of the subject is further provided,
The control unit is
determining whether or not to perform a determination by the determination unit based on the photographing time acquired by the photographing time acquisition unit;
3. The light detection system according to claim 2, wherein when the determination unit does not perform the determination, the first light detection unit is caused to acquire the image of the subject. The optical detection system according to claim 1, further comprising an image receiving unit that receives an image acquired by the first optical detection unit or the second optical detection unit. The optical detection system according to claim 10, characterized in that the image receiving unit is a storage unit that stores the image. The optical detection system according to claim 10, characterized in that the image receiving unit is a display unit that displays the image. a first light detection unit in which a plurality of first photoelectric conversion units each having a photodiode that accumulates electric charge and converts the electric charge into a voltage are arranged on a two-dimensional plane;
a second photodetector unit in which a plurality of second photoelectric conversion units, each of which has an avalanche photodiode that converts incident photons into a pulse, are arranged on a two-dimensional plane;
a photographing time acquisition unit that acquires a photographing time of a subject,
and a control unit that causes one of the first light detection unit or the second light detection unit to obtain an image of the subject based on the shooting time. An imaging optical system;
An imaging device comprising: a light detection system according to claim 1 , which acquires an image formed by the imaging optical system. A method for controlling a photodetection system including a first photodetector having a plurality of first photoelectric conversion units arranged in a two-dimensional plane, the first photodetector having a photodiode that accumulates charge and converts the charge into a voltage, and a second photodetector having a plurality of second photoelectric conversion units arranged in the two-dimensional plane, the second photodetector having an avalanche photodiode that converts incident photons into pulses, the method comprising:
acquiring light amount information of a subject;
and causing one of the first light detection unit and the second light detection unit to acquire an image of the subject based on the light amount information. A method for controlling a photodetection system including a first photodetector having a plurality of first photoelectric conversion units arranged in a two-dimensional plane, the first photodetector having a photodiode that accumulates charge and converts the charge into a voltage, and a second photodetector having a plurality of second photoelectric conversion units arranged in the two-dimensional plane, the second photodetector having an avalanche photodiode that converts incident photons into pulses, the method comprising:
acquiring a time when the subject was photographed;
and causing one of the first light detection unit and the second light detection unit to acquire an image of the subject based on the shooting time. A program for causing a computer to execute the method for controlling an optical detection system according to claim 15 or 16.