Imaging apparatus

Abstract

To suppress the reduction of measurement accuracy when a variable diaphragm is applied to a distance image sensor.SOLUTION: An imaging apparatus 10 includes a light source 18 which repeatedly irradiates an object with pulse light 28, a variable diaphragm 24 through which light from the object passes, a distance image sensor which measures incident light 26 after passing through the variable diaphragm 24 in synchronization with the irradiation with the pulse light 28 and generates a distance image indicating a distance to the object by using the results of a plurality of measurements corresponding to the plurality of irradiations with the pulse light 28, and a control unit 20 which makes the number of measurements used for the calculation of the distance variable according to the setting value of the variable diaphragm.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an imaging device. [Background technology]

[0002] Distance measuring sensors are known that measure the distance to an object by irradiating the object with pulsed light and detecting the reflected light from the object with a photodiode. For example, a method is known in which charges generated in a photodiode are transferred to multiple charge storage nodes in synchronization with the irradiation of the pulsed light, and the distance to the object is calculated from the distribution ratio of the charges accumulated in the multiple charge storage nodes (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-294420 A Summary of the Invention [Problem to be solved by the invention]

[0004] When a variable aperture is provided in the imaging optical system of a range image sensor, changing the setting value of the variable aperture to reduce the opening area can reduce the amount of pulsed light reflected by an object and incident on the range image sensor. The reduction in the amount of incident pulsed light affects the accuracy of distance measurement.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide a technique for suppressing a decrease in measurement accuracy when a variable aperture is applied to a range image sensor. [Means for solving the problem]

[0006] An imaging device according to one embodiment of the present invention comprises a light source that repeatedly irradiates a pulsed light toward an object, a variable aperture through which light from the object passes, a distance image sensor that measures the incident light that passes through the variable aperture in synchronization with the irradiation of the pulsed light and generates a distance image indicating the distance to the object using the results of multiple measurements corresponding to the multiple irradiations of the pulsed light, and a control unit that varies the number of measurements used to calculate the distance depending on the setting value of the variable aperture.

[0007] Any combination of the above components or mutual substitution of the components or expressions of the present invention between methods, devices, systems, etc. are also valid as aspects of the present invention. Effect of the Invention

[0008] According to the present invention, it is possible to suppress a decrease in measurement accuracy when a variable aperture is applied to a range image sensor. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating a schematic configuration of an imaging device according to an embodiment. [Diagram 2] FIG. 1 is a diagram illustrating a configuration of a range image sensor according to an embodiment. [Diagram 3] FIG. 2 is a diagram illustrating a configuration of a pixel unit according to the embodiment. [Figure 4] 4 is a timing chart showing an example of an operation of a pixel unit. [Diagram 5] 5(a) to (c) are diagrams illustrating the operation of the range image sensor according to the first embodiment. [Figure 6] 6(a) to (c) are diagrams illustrating the operation of the range image sensor according to the second embodiment. [Figure 7] 7(a) to (c) are diagrams illustrating the operation of the range image sensor according to the third embodiment. [Figure 8] 8(a) to (c) are diagrams illustrating the operation of the range image sensor according to the fourth embodiment. [Figure 9]9(a) to (c) are diagrams illustrating the operation of the range image sensor according to the fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Specific numerical values ​​and the like shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the drawings, elements that are not directly related to the present invention are omitted.

[0011] 1 is a diagram illustrating a schematic configuration of an imaging device 10 according to an embodiment. The imaging device 10 includes an imaging optical system 12, a light splitting element 14, a plurality of sensors 16a, 16b, and 16c, a light source 18, and a control unit 20. The imaging device 10 is a so-called three-chip camera, and is configured to split incident light 26 using the light splitting element 14 and capture images using the first sensor 16a, the second sensor 16b, and the third sensor 16c, respectively.

[0012] The imaging optical system 12 forms an image of the incident light 26 from the object on the multiple sensors 16a to 16c. The incident light 26 that passes through the imaging optical system 12 travels toward the light splitting element 14. The imaging optical system 12 includes one or more lenses 22 and a variable aperture 24. The imaging optical system 12 may have a fixed focal length or a variable focal length. The imaging optical system 12 includes, for example, multiple lenses 22 and a zoom mechanism (not shown) for moving at least a part of the multiple lenses 22 in the optical axis direction to change the focal length. The variable aperture 24 is disposed, for example, between a front lens and a rear lens of the imaging optical system 12. The variable aperture 24 is provided to change the aperture value or F-number of the imaging optical system 12. When the setting value of the variable aperture 24 is changed, the aperture area of ​​the variable aperture 24 through which the incident light 26 passes is changed, and the F-number of the imaging optical system 12 is changed. The imaging optical system 12 includes, for example, a drive mechanism (not shown) for automatically or manually changing the aperture area of ​​the variable aperture 24.

[0013] The light splitting element 14 splits the incident light 26 that has passed through the imaging optical system 12, and generates a plurality of incident lights 26a, 26b, and 26c that respectively travel toward the plurality of sensors 16a to 16c. The light splitting element 14 is, for example, a three-plate prism.

[0014] The multiple sensors 16a to 16c are image sensors for detecting the incident light 26. At least one of the multiple sensors 16a to 16c is a distance image sensor that generates a distance image indicating the distance to an object. At least one of the multiple sensors 16a to 16c is an image sensor that generates a captured image (e.g., a monochrome image or a color image) of an object. At least one of the multiple sensors 16a to 16c may be a polarization image sensor in which a polarizer is provided for each pixel, or a non-polarization image sensor in which no polarizer is provided. At least one of the multiple sensors 16a to 16c may be an event-based vision sensor (EVS) that outputs an image in which only pixels in which a luminance change is detected are extracted.

[0015] As an example, the first sensor 16a is an imaging sensor (or a non-polarized image sensor) that captures a color image, the second sensor 16b is a polarization image sensor that captures a polarization image, and the third sensor 16c is a distance image sensor. Note that the types and arrangements of the multiple sensors 16a to 16c are not particularly limited, and any type of imaging sensor can be used as any of the multiple sensors 16a to 16c.

[0016] The light source 18 repeatedly irradiates the target with pulsed light 28. The light source 18 is configured to irradiate the pulsed light 28, which is, for example, infrared light. The light source 18 includes, for example, a laser diode array such as a VCSEL (Vertical Cavity Surface Emitting Laser). The light source 18 drives the laser diode array based on a pulse signal supplied from the control unit 20, and irradiates the pulsed light 28 synchronized with the pulse signal.

[0017] The control unit 20 controls the overall operation of the imaging device 10. The control unit 20 controls the operation of at least one of the multiple sensors 16a to 16c. The control unit 20 controls the operation of an imaging sensor which is at least one of the multiple sensors 16a to 16c. The control unit 20 changes the setting value of the variable aperture 24 in accordance with the imaging conditions of at least one of the multiple sensors 16a to 16c. The control unit 20 changes the setting value of the variable aperture 24 in accordance with the imaging conditions of an imaging sensor different from the range image sensor. The control unit 20 changes the setting value of the variable aperture 24 so that the image of the object captured by the imaging sensor has appropriate imaging conditions (e.g. appropriate exposure).

[0018] The control unit 20 controls the operation of the distance image sensor, which is at least one of the sensors 16a to 16c. The control unit 20 controls the operation of the distance image sensor according to the setting value of the variable diaphragm 24. The control unit 20 varies the number of measurements used to calculate the distance in the distance image sensor according to the setting value of the variable diaphragm 24. When the opening area of ​​the variable diaphragm 24 becomes small, the amount of light passing through the variable diaphragm 24 and entering the distance image sensor decreases, and the accuracy of measuring the distance by the distance image sensor may decrease. When the opening area of ​​the variable diaphragm 24 is small (i.e., when the F-number is large), the control unit 20 increases the number of measurements used to calculate the distance, thereby suppressing the decrease in the accuracy of measuring the distance. The method of varying the number of measurements will be described in detail later.

[0019] The control unit 20 controls the operation of the light source 18. The control unit 20 generates a pulse signal to be supplied to the light source 18, and causes the light source 18 to irradiate pulsed light 28 synchronized with the pulse signal.

[0020] The control unit 20 can be configured by, for example, electronic circuits such as a DSP (Digital Signal Processor) or an ISP (Image Signal Processor) for executing signal processing or image processing by hardware. The control unit 20 can be configured by one or more electronic circuits. The control unit 20 may be realized by a combination of hardware and software. The hardware of the control unit 20 may be realized by elements or mechanical devices such as a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), and memories such as a ROM (Read Only Memory) or a RAM (Random Access Memory). The software of the control unit 20 may be realized by a computer program or the like. In this case, various functions provided by the control unit 20 can be realized by cooperation between hardware and software.

[0021] 2 is a diagram showing a schematic configuration of a range image sensor 30 according to an embodiment. The range image sensor 30 includes a measurement unit 32, a readout unit 34, and a calculation unit 36. The range image sensor 30 is at least one of the multiple sensors 16a to 16c shown in FIG. 1, and is configured to measure the incident light 26 that has passed through the variable aperture 24.

[0022] The measurement unit 32 measures the incident light 26 in synchronization with the irradiation of the pulsed light 28 emitted from the light source 18. The measurement unit 32 includes a plurality of pixel units 38 and a pixel driving unit 40. The plurality of pixel units 38 are arranged in a two-dimensional array in the light receiving region of the range image sensor 30. The plurality of pixel units 38 are configured to measure the incident light 26 incident on each pixel unit 38 and output the result of the measurement. The pixel driving unit 40 drives the plurality of pixel units 38 based on a control signal supplied from the control unit 20. The pixel driving unit 40 supplies a driving signal synchronized with the irradiation of the pulsed light 28 to the plurality of pixel units 38, and causes each pixel unit 38 to perform a plurality of measurements corresponding to the multiple irradiations of the pulsed light 28.

[0023] The readout unit 34 reads out the measurement results from the measurement unit 32 and outputs pixel values ​​indicating the measurement results. The readout unit 34 operates based on a control signal supplied from the control unit 20 and reads out the measurement results in a readout period different from the measurement period in which the measurement unit 32 performs the measurement. The readout unit 34 includes a vertical scanning unit 42, a signal processing unit 44, and a horizontal scanning unit 46. The vertical scanning unit 42 generates a row selection signal for reading out the measurement results of the multiple pixel units 38 row by row, and sequentially switches the selected row so that all the measurement results of the multiple pixel units 38 are sequentially read out. The signal processing unit 44 generates pixel values ​​(e.g., digital values) from the measurement results (e.g., analog signals) read out from each pixel unit 38. The horizontal scanning unit 46 generates a column selection signal for sequentially outputting the pixel values ​​generated by the signal processing unit 44, and sequentially switches the selected column so that all the pixel values ​​of the multiple pixel units 38 are sequentially output.

[0024] The calculation unit 36 ​​calculates the distance using the pixel values ​​read by the readout unit 34. The calculation unit 36 ​​generates a distance image indicating the distance to the object by calculating the distance from each pixel value of the multiple pixel units 38. The method of calculating the distance using the pixel values ​​will be described in detail later.

[0025] 3 is a diagram illustrating a schematic configuration of a pixel section 38 according to an embodiment. The pixel section 38 includes a photoelectric conversion section 50 and a plurality of storage circuits 52a, 52b, and 52c. In this embodiment, a case is shown in which one pixel section 38 includes three storage circuits 52a to 52c, but the number of storage circuits included in one pixel section 38 is not limited to three, and may be two, or may be four or more.

[0026] The photoelectric conversion unit 50 is provided in a light receiving region where the incident light 26 is incident, and generates electric charges (carriers) corresponding to the light incident on the pixel unit 38. The photoelectric conversion unit 50 is, for example, a photodiode, for example, a buried type photodiode. The electric charges generated by the photoelectric conversion unit 50 are transferred to one of a plurality of storage circuits 52a to 52c and measured.

[0027] The first storage circuit 52a includes a first charge storage unit 54a, a first transfer transistor 56a, a first reset transistor 58a, a first source follower transistor 60a, and a first selection transistor 62a.

[0028] The first charge accumulation section 54a is a region that accumulates the charges transferred from the photoelectric conversion section 50, and is configured by, for example, a floating diffusion (FD).

[0029] The first transfer transistor 56a is provided between the photoelectric conversion unit 50 and the first charge accumulation unit 54a. The operation of the first transfer transistor 56a is controlled by a first drive signal Sa supplied from the pixel drive unit 40. When the first transfer transistor 56a is on, charge is transferred from the photoelectric conversion unit 50 to the first charge accumulation unit 54a and accumulated therein. When the first transfer transistor 56a is off, the photoelectric conversion unit 50 and the first charge accumulation unit 54a are disconnected, and charge is no longer transferred.

[0030] The first reset transistor 58a resets the charge stored in the first charge storage unit 54a. The operation of the first reset transistor 58a is controlled by a reset signal SR supplied from the vertical scanning unit 42. When the first reset transistor 58a is on, the charge stored in the first charge storage unit 54a is discharged to the outside. When the first reset transistor 58a is off, the charge stored in the first charge storage unit 54a is not discharged to the outside, and the charge stored in the first charge storage unit 54a is maintained.

[0031] The first source follower transistor 60a outputs a voltage value corresponding to the first charge amount Qa stored in the first charge storage section 54a. The first selection transistor 62a is provided between the first source follower transistor 60a and the vertical signal line 64. The operation of the first selection transistor 62a is controlled by a row selection signal SL supplied from the vertical scanning section 42. When the first selection transistor 62a is on, a first voltage value Va corresponding to the first charge amount Qa stored in the first charge storage section 54a is output to the vertical signal line 64. When the first selection transistor 62a is off, the first source follower transistor 60a and the vertical signal line 64 are disconnected.

[0032] The second storage circuit 52b is configured similarly to the first storage circuit 52a, and includes a second charge storage unit 54b, a second transfer transistor 56b, a second reset transistor 58b, a second source follower transistor 60b, and a second selection transistor 62b.

[0033] The operation of the second transfer transistor 56b is controlled by a second drive signal Sb supplied from the pixel drive unit 40. When the second transfer transistor 56b is on, charges are transferred from the photoelectric conversion unit 50 to the second charge storage unit 54b and stored therein. The operation of the second reset transistor 58b is controlled by a reset signal SR supplied from the vertical scanning unit 42. When the second reset transistor 58b is on, the charges stored in the second charge storage unit 54b are discharged to the outside. The operation of the second selection transistor 62b is controlled by a row selection signal SL supplied from the vertical scanning unit 42. When the second selection transistor 62b is on, a second voltage value Vb corresponding to the second charge amount Qb stored in the second charge storage unit 54b is output to the vertical signal line 64.

[0034] The third storage circuit 52c is configured similarly to the first storage circuit 52a and the second storage circuit 52b, and includes a third charge storage unit 54c, a third transfer transistor 56c, a third reset transistor 58c, a third source follower transistor 60c, and a third selection transistor 62c.

[0035] The operation of the third transfer transistor 56c is controlled by a third drive signal Sc supplied from the pixel drive unit 40. When the third transfer transistor 56c is on, charges are transferred from the photoelectric conversion unit 50 to the third charge storage unit 54c and stored therein. The operation of the third reset transistor 58c is controlled by a reset signal SR supplied from the vertical scanning unit 42. When the third reset transistor 58c is on, the charges stored in the third charge storage unit 54c are discharged to the outside. The operation of the third selection transistor 62c is controlled by a row selection signal SL supplied from the vertical scanning unit 42. When the third selection transistor 62c is on, a third voltage value Vc according to the third charge amount Qc stored in the third charge storage unit 54c is output to the vertical signal line 64.

[0036] The signal processing unit 44 generates three pixel values ​​Pa, Pb, and Pc from the three voltage values ​​Va to Vc output to the vertical signal line 64. The signal processing unit 44 generates the three pixel values ​​Pa to Pc, for example, by sampling and holding each of the three voltage values ​​Va to Vc and performing A / D conversion. The three pixel values ​​Pa to Pc generated by the signal processing unit 44 correspond to the amounts of charge Qa to Qc stored in the three storage circuits 52a to 52c, respectively, and indicate the results of measurement in the pixel unit 38.

[0037] 4 is a timing chart showing an example of the operation of the pixel unit 38. The pixel unit 38 operates with a predetermined frame period Tf as a repeating unit. One frame period Tf includes a measurement period Tm and a readout period Tr. The measurement period Tm is a period during which the charges generated in the photoelectric conversion unit 50 are transferred (or distributed) to and stored in the multiple storage circuits 52a to 52c. The readout period Tr is a period during which the charge amounts Qa to Qc stored in the multiple storage circuits 52a to 52c are read out as voltage values ​​Va to Vc.

[0038] In the measurement period Tm, the pulsed light 28 is repeatedly irradiated at a predetermined cycle Tu, and one measurement (also called a unit measurement) is performed in synchronization with one irradiation of the pulsed light 28. The cycle of the unit measurement is the same as the cycle Tu of the irradiation of the pulsed light 28. One unit measurement includes a first accumulation period T1 during which the first drive signal Sa is turned on and charges are accumulated in the first charge accumulation section 54a, a second accumulation period T2 during which the second drive signal Sb is turned on and charges are accumulated in the second charge accumulation section 54b, and a third accumulation period T3 during which the third drive signal Sc is turned on and charges are accumulated in the third charge accumulation section 54c. The length of each accumulation period T1 to T3 is the same as the pulse width Tp during which the pulsed light 28 is irradiated. Therefore, the cycle Tu of one unit measurement is three times the pulse width Tp of the pulsed light 28 (i.e., Tu=3×Tp).

[0039] The pulsed light 28 is reflected by the object and then enters the photoelectric conversion unit 50. The incident light 26 includes a pulse component Ip corresponding to the reflected light of the pulsed light 28 and a background light component Io other than the pulsed light 28. The pulse component Ip enters the photoelectric conversion unit 50 at a timing when a delay time ΔT corresponding to the round-trip distance to the object has elapsed. The timing at which the pulse component Ip enters overlaps with at least one of the first accumulation period T1 and the second accumulation period T2. Therefore, the charge generated in the photoelectric conversion unit 50 by the incidence of the pulse component Ip is transferred to at least one of the first charge accumulation unit 54a and the second charge accumulation unit 54b, and the charge distribution ratio changes according to the delay time ΔT. The third accumulation period T3 is a timing at which the pulse component Ip does not enter, and only the background light component Io enters. Therefore, the charge generated in the photoelectric conversion unit 50 by the background light component Io is transferred to the third charge accumulation unit 54c.

[0040] The first charge storage section 54a stores the charge generated in the photoelectric conversion section 50 in the first accumulation period T1. The charge amount Q1 generated in the photoelectric conversion section 50 in the first accumulation period T1 can be expressed as Q1=Ip·(Tp-ΔT)+Io·Tp. The second charge storage section 54b stores the charge generated in the photoelectric conversion section 50 in the second accumulation period T2. The charge amount Q2 generated in the photoelectric conversion section 50 in the second accumulation period T2 can be expressed as Q2=Ip·ΔT+Io·Tp. The third charge storage section 54c stores the charge generated in the photoelectric conversion section 50 in the third accumulation period T3. The charge amount Q3 generated in the photoelectric conversion section 50 in the third accumulation period T3 can be expressed as Q3=Io·Tp. The delay time ΔT according to the distance of the object can be calculated from these charge amounts Q1 to Q3, and can be expressed as ΔT=Tp(Q2-Q3) / (Q1+Q2-2×Q3).

[0041] The electric charges Q1 to Q3 generated in one unit measurement are very small. Therefore, the delay time ΔT is calculated using the electric charges Qa to Qc accumulated by repeatedly performing the measurement multiple times (for example, N times). The electric charges Qa to Qc accumulated in the electric charge accumulation units 54a to 54c by the N measurements can be expressed as Qa=N×Q1, Qb=N×Q2, and Qc=N×Q3, assuming that the measurement conditions do not change. Therefore, the delay time ΔT can be expressed as ΔT=Tp(Qb-Qc) / (Qa+Qb-2×Qc) using the electric charges Qa to Qc accumulated in the electric charge accumulation units 54a to 54c. In this case, the length of the measurement period Tm is N times the period Tu of one unit measurement (that is, Tm=N×Tu).

[0042] During the readout period Tr, the measurement results are sequentially read out from the pixel units 38. During the readout period Tr, all of the drive signals Sa to Sc for transferring charges from the photoelectric conversion unit 50 to the storage circuits 52a to 52c are turned off, and the transfer of charges is stopped. The charge amounts Qa to Qc stored in the storage circuits 52a to 52c during the measurement period Tm are maintained until they are read out as voltage values ​​Va to Vc during the readout period Tr. The measurement results of the pixel units 38 are output to the vertical signal line 64 at the timing when the row selection signal SL supplied from the vertical scanning unit 42 is turned on. By sequentially switching the readout rows of the pixel units 38, the measurement results of all the pixel units 38 are output in order to the vertical signal line 64. By turning on the reset signal SR at the end of the readout period Tr, the charges stored in the storage circuits 52a to 52c are discharged, and the charge amounts Qa to Qc are reset. After the reset is completed, the measurement period Tm in the next frame period Tf begins.

[0043] 4, the pulsed light 28 is repeatedly irradiated at a predetermined cycle Tu even during the readout period Tr. Therefore, the control unit 20 supplies the light source 18 with a pulse signal for irradiating the pulsed light 28 during both the measurement period Tm and the readout period Tr. Note that the pulsed light 28 does not have to be irradiated during the readout period Tr, and the pulsed light 28 may be stopped during the readout period Tr. In this case, the control unit 20 may supply the light source 18 with a pulse signal for irradiating the pulsed light 28 during the measurement period Tm, and stop supplying the pulse signal during the readout period Tr.

[0044] Next, an embodiment in which the number of unit measurements used to calculate distance is made variable according to the setting value of the variable aperture 24 will be described.

[0045] In the following embodiment, a case where the setting value of the variable aperture 24 is set to "1", "2" or "3" will be described. In the following embodiment, when the setting value of the variable aperture 24 is "1", the F-number of the imaging optical system 12 is "1.4", when the setting value of the variable aperture 24 is "2", the F-number of the imaging optical system 12 is "2.0", and when the setting value of the variable aperture 24 is "3", the F-number of the imaging optical system 12 is "2.8". Therefore, when the setting value of the variable aperture 24 is increased, the F-number of the imaging optical system 12 increases and the opening area of ​​the variable aperture 24 through which the incident light 26 passes decreases. Specifically, when the setting value of the variable aperture 24 increases by one step, the opening area of ​​the variable aperture 24 is halved.

[0046] (First Example) 5(a) to (c) are diagrams illustrating the operation of the distance image sensor 30 according to the first embodiment. FIG. 5(a) illustrates a case where the setting value of the variable aperture 24 is set to "1." The first frame period Tf1 illustrated in FIG. 5(a) includes a first measurement period Tm1 and a readout period Tr. The first measurement period Tm1 is a period for repeatedly executing unit measurements N times (e.g., 500 times). The readout period Tr is a period for reading out pixel values ​​from all pixel units 38. The distance image sensor 30 can calculate the distance from the pixel values ​​for each first frame period Tf1 and generate a distance image.

[0047] FIG. 5(b) shows a case where the setting value of the variable aperture 24 is set to "2". When the setting value is "2", the aperture area of ​​the variable aperture 24 is 1 / 2 of the aperture area S of the variable aperture 24 when the setting value is "1", and the amount of incident light of the pulse component Ip is also 1 / 2. The second frame period Tf2 shown in FIG. 5(b) includes a second measurement period Tm2 and a readout period Tr. The second measurement period Tm2 is a period for repeatedly executing unit measurements N×2 times (for example, 1,000 times). The number of unit measurements executed in the second measurement period Tm is twice the number of unit measurements executed in the first measurement period Tm1. The readout period Tr is a period for reading out pixel values ​​from all of the multiple pixel units 38, and is the same as when the setting value is "1". The distance image sensor 30 can calculate the distance from the pixel value for each second frame period Tf2 and generate a distance image.

[0048] FIG. 5(c) shows a case where the setting value of the variable aperture 24 is set to "3". When the setting value is "3", the aperture area of ​​the variable aperture 24 is 1 / 4 of the aperture area S of the variable aperture 24 when the setting value is "1", and the amount of incident light of the pulse component Ip is also 1 / 4. The third frame period Tf3 shown in FIG. 5(c) includes a third measurement period Tm3 and a readout period Tr. The third measurement period Tm3 is a period for repeatedly executing unit measurements N×4 times (for example, 2,000 times). The number of unit measurements executed in the third measurement period Tm is four times the number of unit measurements executed in the first measurement period Tm1. The readout period Tr is a period for reading out pixel values ​​from all of the multiple pixel units 38, and is the same as when the setting value is "1". The distance image sensor 30 can calculate the distance from the pixel value for each third frame period Tf3 and generate a distance image.

[0049] According to the first embodiment, the number of unit measurements included in a measurement period is changed so that the aperture area (S / k) corresponding to the setting value of the variable diaphragm 24 and the number of unit measurements within one frame period (N×k) are inversely proportional to each other. In other words, the number of measurements used to calculate the distance is changed according to the setting value of the variable diaphragm 24 so that the product of the aperture area (S / k) of the variable diaphragm 24 and the number of unit measurements (N×k) is a constant value (S1×N).

[0050] The control unit 20 determines the number of measurements according to the setting value of the variable aperture 24, and controls the operation of the range image sensor 30 so that pixel values ​​are read out after the determined number of measurements have been performed. The control unit 20 can determine the number of measurements according to the setting value of the variable aperture 24 using a table or formula stored in advance. The range image sensor 30 calculates the distance to an object for each pixel using the results of multiple variable measurements performed within one frame period, and generates a range image.

[0051] In the first embodiment, the length of the measurement period is variable according to the setting value of variable aperture 24, and therefore the pixel value readout cycle is variable. Also, the length of the frame period is variable according to the setting value of variable aperture 24, and therefore the distance image generation cycle is also variable. Therefore, control unit 20 in the first embodiment varies the number of measurements used to calculate distance according to the setting value of variable aperture 24, thereby varying the pixel value readout cycle and the distance image generation cycle.

[0052] (Second Example) 6(a) to 6(c) are diagrams illustrating the operation of a range image sensor 30 according to a second embodiment. The second embodiment differs from the above-described first embodiment in that the length of a frame period that is variable according to the setting value of the variable aperture 24 is an integer multiple of a reference period.

[0053] Fig. 6(a) shows a case where the setting value of the variable diaphragm 24 is "1." Fig. 6(a) is the same as the above-mentioned Fig. 5(a). In the examples shown in Figs. 6(a) to (c), the length of the first frame period Tf1 becomes the reference period.

[0054] FIG. 6(b) shows a case where the setting value of the variable aperture 24 is set to "2". FIG. 6(b) differs from FIG. 5(b) in that a waiting period Tw2 is added between the second measurement period Tm2 and the readout period Tr. The waiting period Tw2 is a period during which measurement is not performed, and during which charge transfer from the photoelectric conversion unit 50 to the multiple storage circuits 52a to 52c is not performed. During the waiting period Tw2, the drive signals Sa to Sc for charge transfer remain off, and the row selection signal SL and the reset signal SR also remain off. Therefore, during the readout period Tr after the end of the waiting period Tw2, the amount of charge stored in the multiple storage circuits 52a to 52c during the second measurement period Tm2 is read out. Therefore, the second frame period Tf2 includes the second measurement period Tm2, ​​the waiting period Tw2, and the readout period Tr. The length of the waiting period Tw2 can be determined so that the second frame period Tf2 is an integer multiple (for example, twice) of the reference period.

[0055] FIG. 6(c) shows a case where the setting value of the variable aperture 24 is set to "3". FIG. 6(c) differs from FIG. 5(c) in that a waiting period Tw3 is added between the third measurement period Tm3 and the readout period Tr. The waiting period Tw3 is a period during which measurement is not performed, similar to the waiting period Tw2, and is a period during which transfer of charges from the photoelectric conversion unit 50 to the multiple storage circuits 52a to 52c is not performed. In the readout period Tr after the end of the waiting period Tw3, the amount of charges stored in the multiple storage circuits 52a to 52c during the third measurement period Tm3 is read out. Therefore, the third frame period Tf3 includes the measurement period Tm3, the waiting period Tw3, and the readout period Tr. The length of the waiting period Tw3 is determined so that the third frame period Tf3 is an integer multiple (for example, three times) of the reference period.

[0056] In the second embodiment as well, the number of unit measurements included in the measurement period is changed so that the aperture area (S / k) corresponding to the setting value of the variable diaphragm 24 and the number of unit measurements (N×k) within one frame period are inversely proportional to each other. In the second embodiment, the frame period is determined to be an integer multiple of the reference period by adding a waiting period between the measurement period and the readout period. As a result, a distance image can be generated at a generation cycle that is an integer multiple of the reference period.

[0057] The control unit 20 determines the number of measurements according to the setting value of the variable aperture 24, and also determines the length of the standby period so that the frame period is an integer multiple of the reference period. The control unit 20 controls the operation of the range image sensor 30 so that the pixel values ​​are read out after the determined standby period has elapsed after the determined number of measurements have been performed. The control unit 20 can determine the number of measurements and the length of the standby period according to the setting value of the variable aperture 24 using a table or formula stored in advance. The range image sensor 30 calculates the distance to the object for each pixel using the results of multiple variable measurements performed within one frame period, and generates a range image.

[0058] In the second embodiment as well, the length of the measurement period is variable according to the setting value of variable aperture 24, and therefore the pixel value readout cycle is variable. In the second embodiment as well, the length of the frame period is variable according to the setting value of variable aperture 24, and therefore the distance image generation cycle is also variable. Therefore, control unit 20 in the second embodiment varies the number of measurements used to calculate distance according to the setting value of variable aperture 24, thereby varying the pixel value readout cycle and the distance image generation cycle.

[0059] In the second embodiment, the frame period is determined to be an integer multiple of the reference period, so the pixel value readout cycle is an integer multiple of the reference period and the distance image generation cycle is also an integer multiple of the reference period. As a result, the pixel value readout timing can be standardized regardless of the setting value of the variable aperture 24, and the distance image generation timing can also be standardized.

[0060] (Third Example) 7(a) to (c) are diagrams showing the operation of a range image sensor 30 according to a third embodiment. The third embodiment is common to the second embodiment in that the length of a frame period that is variable according to the setting value of the variable aperture 24 is an integer multiple of a reference period. The third embodiment differs from the second embodiment in that the measurement period is lengthened instead of providing a standby period.

[0061] Fig. 7(a) shows a case where the setting value of the variable diaphragm 24 is "1." Fig. 7(a) is the same as the above-mentioned Fig. 5(a) and Fig. 6(a). In the examples shown in Figs. 7(a) to (c), the length of the first frame period Tf1 becomes the reference period.

[0062] FIG. 7(b) shows a case where the setting value of the variable aperture 24 is set to "2". In FIG. 7(b), the length of the second measurement period Tma2 is longer than in FIG. 5(b) and FIG. 6(b). The length of the second measurement period Tma2 corresponds to the sum of the second measurement period Tm2 and the waiting period Tw2 in FIG. 6(b). Therefore, the number of unit measurements performed in the second measurement period Tma2 is more than twice the number N (for example, 500 times) of unit measurements performed in the first measurement period Tm1 (for example, 1,300 times). The second frame period Tf2 includes the second measurement period Tma2 and the readout period Tr, and does not include the waiting period Tw2. The length of the second measurement period Tma2 can be determined so that measurements can be performed at least the number (N×2) according to the setting value of the variable aperture 24, and the second frame period Tf2 is an integer multiple (for example, 2 times) of the reference period.

[0063] FIG. 7(c) shows a case where the setting value of the variable aperture 24 is set to "3". In FIG. 7(c), the length of the third measurement period Tma3 is longer than in FIG. 5(b) and FIG. 6(b). The length of the third measurement period Tma3 corresponds to the sum of the third measurement period Tm3 and the waiting period Tw3 in FIG. 6(b). Therefore, the number of unit measurements performed in the third measurement period Tma3 is more than four times (e.g., 2,100 times) the number of unit measurements performed in the first measurement period Tm1 (e.g., 500 times). The third frame period Tf3 includes the third measurement period Tma3 and the readout period Tr, and does not include the waiting period Tw3. The length of the third measurement period Tma3 can be determined so that measurements can be performed at least the number (N×4) according to the setting value of the variable aperture 24, and the third frame period Tf3 is an integer multiple (e.g., 3 times) of the reference period.

[0064] In the third embodiment, the number of measurements is changed according to the setting value of the variable diaphragm 24 so that the product of the opening area (S / k) of the variable diaphragm 24 and the number of unit measurements (N×k) is equal to or greater than a certain value (S1×N). In the third embodiment, the measurement period is lengthened so that the frame period is determined to be an integer multiple of the reference period. As a result, a distance image can be generated at a generation cycle that is an integer multiple of the reference period.

[0065] The control unit 20 determines the number of measurements (lower limit number) according to the setting value of the variable aperture 24, for example, and determines the number of measurements for adjustment (additional number) so that the frame period is an integer multiple of the reference period. The control unit 20 sets the total number of measurements in the measurement period to the lower limit number and the additional number. The control unit 20 controls the operation of the distance image sensor 30 so that pixel values ​​are read out after the determined total number of measurements are performed. The control unit 20 can determine the lower limit number and the additional number using a table or formula stored in advance. The control unit 20 may determine the total number using a table or formula stored in advance, and may not need to determine the lower limit number and the additional number individually. The distance image sensor 30 calculates the distance to the object for each pixel using the results of multiple variable measurements performed within one frame period, and generates a distance image.

[0066] In the third embodiment as well, the length of the measurement period is variable according to the setting value of variable aperture 24, and therefore the pixel value readout cycle is variable. In the third embodiment as well, the length of the frame period is variable according to the setting value of variable aperture 24, and therefore the distance image generation cycle is also variable. Therefore, control unit 20 in the third embodiment varies the number of measurements used to calculate distance according to the setting value of variable aperture 24, thereby varying the pixel value readout cycle and the distance image generation cycle.

[0067] In the third embodiment, the frame period is also determined to be an integer multiple of the reference period, so that the pixel value readout cycle is an integer multiple of the reference period. The distance image generation cycle is also an integer multiple of the reference period. As a result, the pixel value readout timing can be standardized regardless of the setting value of the variable aperture 24, and the distance image generation timing can be standardized.

[0068] In the third embodiment, since the measurement period is extended instead of adding a waiting period, the distance can be calculated using the results of measurements made more than the number of measurements made in the second embodiment. As a result, the third embodiment can more effectively suppress the decrease in measurement accuracy than the second embodiment.

[0069] (Fourth Example) 8(a) to (c) are diagrams illustrating the operation of the range image sensor 30 according to the fourth embodiment. In the fourth embodiment, the distance is calculated using a plurality of pixel values ​​read out at different timings according to the setting value of the variable aperture 24. In the fourth embodiment, the operation of the pixel unit 38 is not changed according to the setting value of the variable aperture 24, and the operation of the pixel unit 38 is standardized. In the fourth embodiment, the readout period in which pixel values ​​are read out from the pixel unit 38 is constant.

[0070] FIG. 8(a) shows a case where the setting value of the variable aperture 24 is set to "1". FIG. 8(a) is the same as FIG. 5(a), FIG. 6(a) and FIG. 7(a) described above. The first frame period Tf1 includes a first measurement period Tm1 and a first readout period Tr1. The first measurement period Tm1 is a period for repeatedly executing unit measurements N times (e.g., 500 times). The calculation unit 36 ​​calculates the distance using pixel values ​​indicating the results of the N unit measurements executed in the first measurement period Tm. In this case, the generation cycle of the distance image is the same as the readout cycle of the pixel values.

[0071] FIG. 8(b) shows a case where the setting value of the variable aperture 24 is set to "2". The second frame period Tf2 includes a first measurement period Tm1, a first readout period Tr1, a second measurement period Tm2, ​​and a second readout period Tr2. The first measurement period Tm1 and the second measurement period Tm2 are the same as the first measurement period Tm1 in FIG. 8(a) and are periods for repeatedly executing unit measurements N times (for example, 500 times). The first readout period Tr1 and the second readout period Tr2 are the same as the first readout period Tr1 in FIG. 8(a). The calculation unit 36 ​​calculates the distance using the pixel value read out in the first readout period Tr1 and the pixel value read out in the second readout period Tr2. The calculation unit 36 ​​calculates the distance using two pixel values ​​read out at different times. The calculation unit 36 ​​adds the pixel value read out in the first readout period Tr1 and the pixel value read out in the second readout period Tr2, and calculates the distance using the added value. The sum indicates the result of N×2 unit measurements performed during two measurement periods Tm1 and Tm2. Therefore, the calculation unit 36 ​​calculates the distance using the results of N×2 measurements. In this case, the generation cycle of the distance image is twice the readout cycle of the pixel values.

[0072] FIG. 8(c) shows a case where the setting value of the variable aperture 24 is set to "3". The third frame period Tf3 includes a first measurement period Tm1, a first readout period Tr1, a second measurement period Tm2, ​​a second readout period Tr2, a third measurement period Tm3, a third readout period Tr3, a fourth measurement period Tm4, and a fourth readout period Tr4. The measurement periods Tm1 to Tm4 are the same as the first measurement period Tm1 in FIG. 8(a) and are periods for repeatedly executing unit measurements N times (for example, 500 times). The readout periods Tr1 to Tr4 are the same as the first readout period Tr1 in FIG. 8(a). The calculation unit 36 ​​calculates the distance using the pixel values ​​read out in the first readout period Tr1, the pixel values ​​read out in the second readout period Tr2, the pixel values ​​read out in the third readout period Tr3, and the pixel values ​​read out in the fourth readout period Tr4. The calculation unit 36 ​​calculates the distance using four pixel values ​​read out at different times. The calculation unit 36 ​​adds up the four pixel values ​​read out in the four readout periods Tr1 to Tr4, and calculates the distance using the added value. The added value indicates the result of N×4 unit measurements performed in the four measurement periods Tm1 to Tm4. Therefore, the calculation unit 36 ​​calculates the distance using the results of N×4 measurements. In this case, the generation cycle of the distance image is four times the readout cycle of the pixel values.

[0073] In the fourth embodiment as well, the number of measurements used to calculate the distance is changed so that the aperture area (S / k) corresponding to the setting value of the variable diaphragm 24 and the number of unit measurements (N×k) within one frame period are inversely proportional to each other. In the fourth embodiment, instead of changing the length of the measurement period, the number of pixel values ​​used to calculate the distance is changed.

[0074] The control unit 20 determines the number of measurements according to the setting value of the variable aperture 24, and determines the number of pixel values ​​used to calculate the distance. The control unit 20 can determine the number of measurements and the number of pixel values ​​according to the setting value of the variable aperture 24 using a table or formula stored in advance. The control unit 20 may determine only the number of pixel values ​​using a table or formula stored in advance, and may not determine the number of measurements. The control unit 20 controls the operation of the distance image sensor 30 so that the distance is calculated using the determined number of pixel values. The calculation unit 36 ​​can include a storage unit that temporarily stores the pixel values ​​read out during the readout period, and can calculate the distance using one or more pixel values ​​stored in the storage unit. The distance image sensor 30 calculates the distance to the object for each pixel using the results of multiple measurements performed within one frame period, and generates a distance image.

[0075] In the fourth embodiment, the lengths of the measurement period and the readout period are fixed, so the pixel value readout cycle is constant. As a result, the operation of the pixel unit 38 can be standardized regardless of the setting value of the variable aperture 24. In the fourth embodiment, the distance is calculated using a number of pixel values ​​that varies depending on the setting value of the variable aperture 24, so the distance image generation cycle varies depending on the setting value of the variable aperture 24. Therefore, the control unit 20 in the fifth embodiment varies the number of measurements used to calculate the distance depending on the setting value of the variable aperture 24, and varies the distance image generation cycle, but does not vary the pixel value readout cycle.

[0076] (Fifth Example) 9(a) to 9(c) are diagrams showing the operation of a range image sensor 30 according to a fifth embodiment. In the fifth embodiment, similar to the fourth embodiment, distance is calculated using a plurality of pixel values ​​read out at different timings according to the setting value of the variable aperture 24. The fifth embodiment differs from the fourth embodiment in that the generation cycle of the range image is constant, rather than being changed according to the setting value of the variable aperture 24.

[0077] Fig. 9(a) shows a case where the setting value of the variable diaphragm 24 is set to "1." Fig. 9(a) is the same as Fig. 8(a) described above.

[0078] FIG. 9(b) shows a case where the setting value of the variable aperture 24 is set to "2". The operation of the pixel unit 38 in the second frame period Tf2 is the same as that in FIG. 8(b) described above. The calculation unit 36 ​​includes a first storage unit that stores pixel values ​​read out in the first readout period Tr1, and a second storage unit that stores pixel values ​​read out in the second readout period Tr2. The pixel values ​​stored in the first storage unit are updated by pixel values ​​read out in the first readout period Tr1, but are not updated by pixel values ​​read out in the second readout period Tr2, and the previous values ​​are maintained. The pixel values ​​stored in the second storage unit are updated by pixel values ​​read out in the second readout period Tr2, but are not updated by pixel values ​​read out in the first readout period Tr1, and the previous values ​​are maintained. The calculation unit 36 ​​calculates the distance using two pixel values ​​stored in the first storage unit and the second storage unit, and calculates the distance using, for example, the sum of the two pixel values. The calculation unit 36 ​​generates a distance image at the timing when the pixel value in one of the first storage unit and the second storage unit is updated. Therefore, the generation cycle of the distance image is the same as the readout cycle of the pixel values.

[0079] FIG. 9(c) shows a case where the setting value of the variable aperture 24 is set to "3". The operation of the pixel unit 38 in the third frame period Tf3 is the same as that in FIG. 8(c) described above. The calculation unit 36 ​​includes a first storage unit that stores pixel values ​​read out in the first readout period Tr1, a second storage unit that stores pixel values ​​read out in the second readout period Tr2, a third storage unit that stores pixel values ​​read out in the third readout period Tr3, and a fourth storage unit that stores pixel values ​​read out in the fourth readout period Tr4. The pixel values ​​stored in the first storage unit are updated by the pixel values ​​read out in the first readout period Tr1, but are not updated by the pixel values ​​read out in the other readout periods Tr2 to Tr4, and the previous values ​​are maintained. The pixel values ​​stored in the second storage unit are updated by the pixel values ​​read out in the second readout period Tr2, but are not updated by the pixel values ​​read out in the other readout periods Tr1, Tr3, and Tr4, and the previous values ​​are maintained. The pixel values ​​stored in the third storage unit are updated by pixel values ​​read out in the third readout period Tr3, but are not updated by pixel values ​​read out in the other readout periods Tr1, Tr2, and Tr4, and the previous values ​​are maintained. The pixel values ​​stored in the fourth storage unit are updated by pixel values ​​read out in the fourth readout period Tr4, but are not updated by pixel values ​​read out in the other readout periods Tr1 to Tr3, and the previous values ​​are maintained. The calculation unit 36 ​​calculates the distance using the four pixel values ​​stored in the first storage unit to the fourth storage unit, and calculates the distance using, for example, the sum of the four pixel values. The calculation unit 36 ​​generates a distance image at the timing when any pixel value in the multiple storage units is updated. Therefore, the generation cycle of the distance image is the same as the readout cycle of the pixel values.

[0080] In the fifth embodiment as well, the number of measurements used to calculate the distance is changed so that the aperture area (S / k) corresponding to the setting value of the variable diaphragm 24 and the number of unit measurements (N×k) within one frame period are inversely proportional to each other. In the fifth embodiment, as in the fourth embodiment, instead of changing the length of the measurement period, the number of pixel values ​​used to calculate the distance is changed. In the fifth embodiment, the length of the frame period for sequentially storing the number of pixel values ​​used to calculate the distance is changed.

[0081] The control unit 20 determines the number of measurements according to the setting value of the variable aperture 24 and determines the number of pixel values ​​used to calculate the distance. The control unit 20 can determine the number of measurements or the number of pixel values ​​according to the setting value of the variable aperture 24 using a table or formula stored in advance. The control unit 20 controls the operation of the distance image sensor 30 so that the distance is calculated using the determined number of pixel values. The calculation unit 36 ​​can include a storage unit that temporarily stores the pixel values ​​read out during the readout period, and can calculate the distance using one or more pixel values ​​stored in the storage unit. The distance image sensor 30 calculates the distance to the object for each pixel using the results of multiple measurements performed within one frame period and generates a distance image.

[0082] In the fifth embodiment, the lengths of the measurement period and the readout period are fixed, so the pixel value readout cycle is constant. As a result, the operation of the pixel unit 38 can be standardized regardless of the setting value of the variable aperture 24. In the fifth embodiment, a distance image is generated when any of the multiple pixel values ​​used to calculate the distance is updated, so the generation cycle of the distance image is not changed according to the setting value of the variable aperture 24, and the generation cycle of the distance image is constant. Therefore, the control unit 20 according to the fifth embodiment varies the number of measurements used to calculate the distance according to the setting value of the variable aperture 24, but does not vary the pixel value readout cycle or the generation cycle of the distance image.

[0083] In the above-described embodiment, the variable throttle 24 has three setting values. In this embodiment, the number of setting values ​​of the variable throttle 24 is not particularly limited, and may be two, or may be four or more. The setting values ​​of the variable throttle 24 may be set in a stepwise or discrete manner, or may be continuously set.

[0084] In the above embodiment, the incident light 26 is split using the light splitting element 14 and incident on the multiple sensors 16a to 16c. In another embodiment, the imaging device 10 may be configured not to include the light splitting element 14, and the incident light 26 that has passed through the imaging optical system 12 may be incident on only a single distance image sensor. In this case, the setting value of the variable aperture 24 may be changed according to the imaging conditions of the distance image sensor. For example, by changing the setting value of the variable aperture 24, the focal depth of the imaging optical system 12 may be changed, and the range of distances to objects that can be measured by the distance image sensor may be changed.

[0085] The present invention has been described above with reference to the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, and appropriate combinations or substitutions of the configurations shown in each display example are also included in the present invention.

[0086] In the first to fourth embodiments, the generation cycle of the distance image is variable, but it should be understood that the generation cycle of the distance image of different aperture values ​​can be adjusted by adding an appropriate new waiting period. Specifically, the generation cycle of the distance image of a certain aperture value can be adjusted to the generation cycle of the distance image of another aperture value with a smaller amount of light by adding a new waiting time. Adjusting the generation cycle of the distance image in this way has the advantage of simplifying the design of the downstream system for acquiring the distance image. When adjusting to the generation cycle of the aperture value with the smallest amount of light or a specific generation cycle longer than that, the generation cycle of the distance image of all aperture values ​​can be aligned. In any of the modified examples of the first to fourth embodiments described above, the pixel value readout cycle and the generation cycle of the distance image may be fixed regardless of the setting value of the variable aperture 24. In this case, the length of the measurement period may be made variable and the length of the waiting period from the end of the measurement period to the start of the readout period may be made variable depending on the setting value of the variable aperture 24, so that the total of the measurement period, the waiting period, and the readout period is constant. [Explanation of symbols]

[0087] 10...imaging device, 14...light dividing element, 18...light source, 20...control unit, 24...variable aperture, 26...incident light, 28...pulsed light, 30...distance image sensor, 32...measurement unit, 34...readout unit, 36...calculation unit, 38...pixel unit, 40...pixel driving unit, 42...vertical scanning unit, 44...signal processing unit, 46...horizontal scanning unit, 50...photoelectric conversion unit, 52a-52c...storage circuit.

Claims

1. A light source that repeatedly irradiates a target with pulsed light; a variable aperture through which light from the object passes; a distance image sensor that measures the incident light that has passed through the variable diaphragm in synchronization with the irradiation of the pulsed light, and generates a distance image indicating the distance to the object using results of a plurality of measurements corresponding to a plurality of irradiations of the pulsed light; a control unit that varies the number of measurements used to calculate the distance according to a setting value of the variable aperture. Imaging device.

2. The imaging device according to claim 1 , wherein the control unit varies a generation cycle of the distance images in accordance with a setting value of the variable aperture.

3. The distance image sensor includes: a pixel unit that measures the incident light in synchronization with the irradiation of the pulsed light; a readout unit that reads out pixel values ​​indicating the results of the measurement from the pixel unit; a calculation unit that calculates the distance using the pixel value, the control unit varies a read cycle of the pixel values ​​by the readout unit in accordance with a setting value of the variable aperture. The imaging device according to claim 1 .

4. The distance image sensor includes: a pixel unit that measures the incident light in synchronization with the irradiation of the pulsed light; a readout unit that reads out pixel values ​​indicating the results of the measurement from the pixel unit; a calculation unit that calculates the distance using the pixel value, the calculation unit is capable of calculating the distance using a plurality of pixel values ​​read out at different timings by the readout unit, the control unit varies the number of pixel values ​​used in the distance calculation in accordance with a setting value of the variable aperture. The imaging device according to claim 1 .

5. a light dividing element that divides the incident light that has passed through the variable diaphragm into a first incident light and a second incident light that proceed toward the range image sensor; an image sensor that detects the second incident light and generates an image of the object; the control unit changes a setting value of the variable aperture in accordance with an imaging condition of the imaging sensor; The control unit varies the number of measurements used to calculate the distance in accordance with a changed setting value of the variable aperture. The imaging device according to claim 1 .

Images