Imaging system, imaging apparatus, control method, and control program

Abstract

Provide are an imaging system, an imaging apparatus, a control method, and a control program that are capable of reducing PLS noise.　An imaging system (1) comprises: an imaging lens including a focus lens (12); an imaging element (14) having a plurality of pixels and capable of performing a first drive for reading out, to an electric charge-holding unit, electric charges accumulated through simultaneous exposure of the plurality of pixels to light; and a system control unit (16). The system control unit (16) performs first focus control for moving the focus lens (12) during a first period in which electric charges are read out from the electric charge-holding unit after the first drive.

Description

Imaging System, Imaging Device, Control Method, and Control Program

[0001] The present invention relates to an imaging system, an imaging device, a control method, and a control program.

[0002] Patent Document 1 describes an image pickup device including a photoelectric conversion unit that converts light into electric charges, a first charge holding unit that holds the electric charges converted in the photoelectric conversion unit, a second charge holding unit that holds electric charges for correcting a signal based on the electric charges held in the first charge holding unit, and an accumulation unit that accumulates the electric charges held in at least one of the first charge holding unit and the second charge holding unit.

[0003] Patent Document 2 describes an imaging device including an imaging unit having a region in which a plurality of pixels each having a photoelectric conversion unit that generates electric charges by photoelectric conversion and an accumulation unit that accumulates the electric charges generated in the photoelectric conversion unit are provided in a first direction and a second direction, and a control unit that performs first control to transfer the electric charges generated in the photoelectric conversion unit to the accumulation unit in each of the plurality of pixels provided in the first direction and the second direction and output a signal based on the electric charges accumulated in the accumulation unit from the plurality of pixels in an order determined based on the position of a high-brightness region.

[0004] Japanese Patent Application Laid-Open No. 2024-054607, Japanese Patent Application Laid-Open No. 2022-127306

[0005] One embodiment of the technology according to the present disclosure provides an imaging system, an imaging device, a control method, and a control program capable of reducing PLS noise.

[0006] (1) An imaging system including an imaging lens including a focus lens, an image pickup device having a plurality of pixels and capable of first driving to read out the electric charges accumulated by simultaneous exposure of the plurality of pixels to a charge holding unit, and a processor, wherein the processor performs first focus control to move the focus lens in a first period after the first driving and when reading out the electric charges from the charge holding unit.

[0007] (2) The imaging system described in (1), wherein the processor performs the first focus control immediately after the first drive and during the first period in which the charge is read from the charge holding unit.

[0008] (3) The imaging system described in (1), wherein the processor moves the focus lens by a predetermined amount in the first focus control.

[0009] (4) The imaging system described in (3), wherein the processor, in the first focus control, causes the focus lens to move by a predetermined amount to defocus.

[0010] (5) The imaging system described in (1), wherein the processor moves the focus lens in the first focus control based on image data obtained by imaging performed before the first drive and the result of distance measurement performed before the first drive.

[0011] (6) An imaging system according to any one of (1) to (5), wherein the processor performs a high-luminance subject detection process on image data obtained by imaging performed before the first drive, and performs the first focus control based on the result of the detection process.

[0012] (7) The imaging system according to (6), wherein the processor performs the first focus control during the first period when the high-luminance subject is detected and the high-luminance subject is moving.

[0013] (8) An imaging system according to any one of (1) to (7), wherein the imaging lens includes an aperture, and the processor performs the first focus control and the first aperture control for driving the aperture during the first period.

[0014] (9) The imaging system described in (8), wherein the processor drives the first aperture control in the direction of opening the aperture.

[0015] (10) An imaging system according to (8), wherein the processor drives the aperture in the direction of closing in the first aperture control.

[0016] (11) An imaging system according to any one of (1) to (10), wherein the processor determines the amount of movement of the focus lens in the first focus control based on the time from when the charge is read out from the charge holding unit until the simultaneous exposure is started.

[0017] (12) An imaging system according to any one of (8) to (10), wherein the processor determines the amount of movement of the focus lens in the first focus control and the amount of movement of the aperture in the first aperture control based on the time from the start of reading out the charge from the charge holding unit until the start of simultaneous exposure.

[0018] (13) An imaging system according to any one of (1) to (12), comprising a vibration isolation mechanism, wherein the processor performs the first focus control and the first vibration isolation control for controlling the vibration isolation mechanism during the first period.

[0019] (14) An imaging system as described in (13), wherein the first vibration isolation control is a control that operates the vibration isolation mechanism to cause the image to blur with respect to the image sensor.

[0020] (15) An imaging system according to any one of (1) to (14), wherein the imaging lens includes a zoom mechanism, and the processor performs the first focus control and the first zoom control that drives the zoom mechanism during the first period.

[0021] (16) The imaging system described in (15), wherein the processor drives the zoom mechanism to the telephoto side in the first zoom control.

[0022] (17) An imaging system according to any one of (1) to (16), wherein the processor performs a second focus control after the first period to return the position of the focus lens that was moved by the first focus control.

[0023] (18) An imaging device comprising: an imaging lens including a focus lens that performs imaging, an image sensor having a plurality of pixels and capable of a first drive that reads the charge accumulated by the simultaneous exposure of the plurality of pixels to a charge holding unit, and a processor, wherein the processor performs a first focus control that moves the focus lens after the first drive and during a first period in which the charge is read from the charge holding unit.

[0024] (19) A control method for an imaging apparatus comprising an imaging lens including a focus lens, an imaging sensor having a plurality of pixels and capable of a first drive that reads the charge accumulated by the simultaneous exposure of the plurality of pixels to a charge holding unit, and a processor, wherein the processor performs a first focus control that moves the focus lens after the first drive and during a first period in which the charge is read from the charge holding unit.

[0025] (20) A control program that causes the processor of an imaging device, which includes an imaging lens including a focus lens, an imaging sensor having a plurality of pixels and capable of a first drive that reads the charge accumulated by the simultaneous exposure of the plurality of pixels to a charge holding unit, to execute a process that moves the focus lens during a first period after the first drive and when the charge is read from the charge holding unit.

[0026] (21) An imaging system comprising: an imaging lens; an image sensor having a plurality of pixels and capable of a first drive that reads the charge accumulated by the simultaneous exposure of the plurality of pixels to a charge holding unit; and a processor, wherein the processor reduces the intensity of light received by the image sensor by controlling at least one of the imaging lens or the image sensor after the first drive and during a first period in which the charge is read from the charge holding unit.

[0027] According to the present invention, it is possible to provide an imaging system, imaging device, control method, and control program that can reduce PLS noise.

[0028] Figure 1 is a diagram showing the configuration of the imaging system 1, including the imaging device 10 of this embodiment. Figure 2 is a diagram showing an example of the control sequence of the system control unit 16 when capturing a still image. Figure 3 is a diagram showing an example of the movement of a subject during the charge readout period. Figure 4 is a diagram showing an example of PLS ​​noise generated in the captured image due to the movement of the subject. Figure 5 is a flowchart showing the control processing of the system control unit 16 during imaging. Figure 6 is a flowchart showing a modified example 1 of the control processing of the system control unit 16 during imaging. Figure 7 is a flowchart showing a modified example 2 of the control processing of the system control unit 16 during imaging. Figure 8 is a flowchart showing a modified example 3 of the control processing of the system control unit 16 during imaging. Figure 9 is a flowchart showing a modified example 4 of the control processing of the system control unit 16 during imaging. Figure 10 is a flowchart showing a modified example 5 of the control processing of the system control unit 16 during imaging. Figure 11 is a flowchart showing a modified example 6 of the control processing of the system control unit 16 during imaging. Figure 12 is a flowchart showing a modified example 7 of the control processing of the system control unit 16 during imaging. Figure 13 is a diagram showing an example of the change in the imaging area due to zoom control. Figure 14 is a diagram showing a modified version of the imaging system 1. Figure 15 is a flowchart showing a modified example 8 of the control processing of the system control unit 16 during imaging.

[0029] Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

[0030] <Imaging System> Figure 1 is a diagram showing the configuration of the imaging system 1, including the imaging device 10 of this embodiment. As shown in Figure 1, the imaging system 1 includes an imaging lens 11, a focusing lens 12, an aperture 13, an image sensor 14, a digital signal processing unit 15, and a system control unit 16. The imaging system 1 also includes an EVF (Electronic View Finder) 17, a display LCD (Liquid Crystal Display) 18, a card storage unit 19, and an operation unit 20. The imaging system 1 is, for example, a digital still camera or a digital video camera capable of capturing video.

[0031] The imaging lens 11 is a lens for forming an image on the image sensor 14 with incident light. The focusing lens 12 is a lens that can move in the optical axis direction. The focusing lens 12 is a lens for adjusting the focus of the imaging optical system, which includes the imaging lens 11 and the aperture 13, and is composed of a single lens or multiple lenses. The focusing lens 12 moves in the optical axis direction based on the imaging control signal transmitted from the system control unit 16, thereby changing the position of the principal point of the focusing lens 12 along the optical axis direction and changing the focal position on the subject side. The imaging lens 11 and the focusing lens 12 are examples of imaging lenses including the focusing lens of the present invention.

[0032] The aperture 13 is mechanically adjustable in terms of the amount of incident light. The aperture 13 changes its aperture amount (F-number) based on a drive control signal transmitted from the system control unit 16.

[0033] The image sensor 14 captures an image of a subject through an imaging optical system including an imaging lens 11, a focusing lens 12, and an aperture 13. The image sensor 14 captures an image of a subject based on an imaging control signal transmitted from the system control unit 16. The image sensor 14 has a light-receiving surface in which multiple pixels are arranged in two dimensions, and the imaging optical system converts the image of the subject formed on the light-receiving surface into a pixel signal using the multiple pixels and outputs it. The image sensor 14 captures the target subject at a predetermined frame rate. A "predetermined frame rate" refers to, for example, tens of frames per second to hundreds of frames per second. The image sensor 14 is composed of, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor.

[0034] The image sensor 14 has, for example, a photodiode in each of its multiple pixels that generates and stores an electric charge corresponding to the amount of light received, and a charge holding unit that reads out the charge stored in the photodiode. The image sensor 14 is capable of simultaneous exposure of multiple pixels and simultaneous readout control that reads out the charge stored in the photodiodes of the multiple pixels during the simultaneous exposure to the charge holding unit. "Simultaneous exposure of multiple pixels" means that all pixels are exposed with a very short time difference, and that there is a time when all pixels are exposed. However, due to the characteristics of the electronic circuit and control, minute time differences at the nanosecond or picosecond level may exist. "Reading out the charge stored in multiple pixels to the charge holding unit" means that the charge stored in multiple pixels is read out to the charge holding unit at the same time for all pixels. The image sensor 14 is a global shutter type image sensor that exposes all pixels simultaneously. Simultaneous readout control in the image sensor 14 is an example of the "first drive" of the present invention.

[0035] The digital signal processing unit 15 processes the image signal output from the image sensor 14 to generate image data suitable for display on the display LCD 18 and image data suitable for storage in the card storage unit 19. The digital signal processing unit 15 generates image data by applying signal processing such as demosaicing and gamma correction to the image data output from the image sensor 14. The digital signal processing unit 15 executes each signal processing based on the image control signal transmitted from the system control unit 16.

[0036] The system control unit 16 provides overall control of the entire imaging system 1. The system control unit 16 is a processor that executes programs and performs processing. The system control unit 16 is an example of a "processor" in the present invention. The system control unit 16 may be composed of one of the various processors, or it may be composed of a combination of two or more processors of the same or different types.

[0037] The system control unit 16 drives the imaging lens 11, the focusing lens 12, the aperture 13, and the image sensor 14, and outputs the subject image captured through the imaging optical system including the imaging lens 11, the focusing lens 12, and the aperture 13 as an image signal from the image sensor 14 to the digital signal processing unit 15.

[0038] Furthermore, the system control unit 16 performs high-brightness subject detection processing by analyzing image data obtained by imaging performed before simultaneous readout (global transfer) control. "Image data obtained by imaging performed before simultaneous readout control" is, for example, the through image displayed on the display LCD 18. "High-brightness subject" is, for example, a subject that has a brightness value above a predetermined threshold (in the state of proper exposure). If the pixel value can take values ​​from 0 to 255, the predetermined threshold can be, for example, 255 (saturation state). Also, "high-brightness subject" may be a subject with an extremely high brightness value compared to other areas.

[0039] The system control unit 16 controls the movement of the focus lens 12 after the simultaneous readout control (first drive) of the image sensor 14 and during the period (first period) in which the charge accumulated by simultaneous exposure is read from the charge holding unit. This control is a defocus control that moves the focus lens 12 in order to reduce the intensity of light received by the image sensor 14 by making the image formed on the image sensor 14 defocused. Defocus control is an example of the first focus control of the present invention.

[0040] "After simultaneous readout control" refers, for example, to the moment immediately after the completion of simultaneous readout control, that is, the start of the readout when the charge read out to the charge holding unit during simultaneous readout control is read out as an image signal. The readout period during which the charge read out to the charge holding unit is read out as an image signal is the period during which each pixel is read out sequentially, and therefore is a period during which PLS (Parasitic Light Sensitivity) noise can occur. PLS noise is noise that degrades the image when light leaks into the charge holding unit.

[0041] The EVF 17 is an electronic viewfinder capable of viewing images converted by the digital signal processing unit 15. The EVF 17 allows the user to view the image displayed on the LCD 18 through the viewfinder. The LCD 18 is composed of, for example, an organic EL (electroluminescence) panel or a liquid crystal panel. The card storage unit 19 is where an SD memory card is inserted. The operation unit 20 receives instruction signals from the user. The operation unit 20 includes a touch panel integrated with the LCD 18 and various buttons.

[0042] <Control Sequence During Image Capture> Figure 2 shows an example of the control sequence of the system control unit 16 during still image capture.

[0043] In FIG. 2, "defocus control" is control that defocuses the image formed on the imaging device 14 by moving the focus lens 12 by a predetermined amount. "ND control: OFF" is control that does not intentionally defocus the image formed on the imaging device 14, for example, control that maintains the focus position set by autofocus or manual focus. "Defocus control: ON" is control that intentionally defocuses the image formed on the imaging device 14, for example, control that changes the focus position set by autofocus or manual focus.

[0044] "This exposure" is the exposure when capturing a still image. "Reading" is the reading of the charges read into the charge holding section during this exposure from the charge holding section as image signals in sequence. "Global reset" is the erasure (GR) of the charges accumulated in the photodiodes of each pixel. "Global transfer" is the simultaneous reading (GS) of the charges of a plurality of pixels accumulated during this exposure into the charge holding section for all pixels simultaneously.

[0045] In the state of the live view 47 where an image of the subject is being captured while being displayed on the display LCD 18, the system control unit 16 analyzes the data of the through image to perform a detection process of whether a high-brightness subject exists.

[0046] In the state of the live view 47, assume that the user presses, for example, the release button at time t1 to capture a still image.

[0047] When the release button is pressed, the system control unit 16 causes the imaging device 14 to execute a global reset to erase the charges accumulated in the photodiodes of each pixel. When the global reset is completed, the system control unit 16 causes a simultaneous exposure of a plurality of pixels by this exposure 42. At time t2, the system control unit 16 causes the imaging device 14 to execute a simultaneous reading control (global transfer) that reads out the charges accumulated in the photodiodes of a plurality of pixels by this exposure 42 into the charge holding section for all pixels simultaneously.

[0048] When the global transfer is completed, the system control unit 16 starts the process of reading 43, which sequentially reads out the charges read into the charge holding unit in the main exposure 42 as image signals for each pixel. Also, when the global transfer is completed, immediately after that, the system control unit 16 turns on the control signal 41 for defocus control and performs defocus control to move the focus lens 12 to a defocus state.

[0049] When the process of reading 43 is completed (time t3), the system control unit 16 turns off the control signal 41 for defocus control. Also, when the imaging of a still image is completed, the system control unit 16 returns to the position based on the focus lens 12 and returns to the live view 47 (time t3).

[0050] Although omitted in FIG. 2, when returning to the live view 47, the system control unit 16 may execute the live view exposure of the first frame image after imaging during the period of reading 43 that sequentially reads out the charges of the main exposure 42, that is, starting from a timing before time t3. When performing the live view exposure, the system control unit 16 causes the image sensor 14 to perform a global reset before the start thereof, and erases the charges accumulated in the photodiodes of each pixel in the main exposure 42.

[0051] <Generation of PLS Noise> Next, an example of the generation of PLS noise during still image imaging will be described with reference to FIGS. 3 and 4. FIG. 3 is a diagram showing an example of the movement of a subject during the charge reading period. FIG. 4 is a diagram showing an example of PLS noise generated in the captured image due to the movement of the subject.

[0052] As shown in FIG. 3, assume that the subject to be imaged is a vehicle 51. The vehicle 51 is assumed to be traveling at a constant speed, for example. Also, assume that the vehicle 51 is traveling with its headlights 52 on.

[0053] As described above, in the live view state, when the user presses the release button, after the main exposure for still image imaging is executed, the readout process that sequentially reads out the charges read into the charge holding unit in the main exposure as image signals for each pixel is started.

[0054] When the release button is pressed while the vehicle 51 is moving, during the readout process, the vehicle 51 moves from driving position A to driving position B within the still image capture range 50 shown in Figure 3.

[0055] In this case, since the vehicle 51 has its headlights 52 illuminated, the trajectory of the headlights 52, which moves along with the movement of the vehicle 51 during the readout period, is superimposed as a bright spot on the still image of the vehicle 51. As a result, the trajectory of the headlights 52 appears as PLS noise 53 in the still image of the vehicle 51, as shown in Figure 4.

[0056] In the imaging system 1, during the readout process in which the charge read out to the charge holding unit during this exposure is sequentially read out as an image signal for each pixel, defocus control is performed by moving the focus lens 12 to a defocus state. This blurs bright spots and reduces the intensity (maximum intensity) of the light received by the image sensor 14 in those areas, thereby suppressing the generation of PLS ​​noise 53.

[0057] <Control Processing of System Control Unit 16 During Image Capture> Figure 5 is a flowchart showing the control processing of the system control unit 16 during image capture. This control processing is started, for example, when the mode setting button on the operation unit 20 is set to still image capture mode.

[0058] The system control unit 16 starts a live view display process to display a live view image of the subject on the display LCD 18 (step S11). The system control unit 16 also starts a detection process to analyze the data of the through image to determine whether or not a high-brightness subject exists (step S11). The high-brightness subject detection process is performed repeatedly. Examples of high-brightness subjects include lights from vehicles and aircraft.

[0059] Next, the system control unit 16 determines whether or not still image capture has been performed (step S12). The system control unit 16 determines whether or not image capture has been performed, for example, by whether or not the release button has been pressed.

[0060] If it is determined in step S12 that imaging has not been performed (step S12: No), the system control unit 16 repeats the process of step S12. If it is determined in step S12 that imaging has been performed (step S12: Yes), the system control unit 16 determines whether or not a high-luminance subject was detected in the detection process of step S11 (step S13).

[0061] If no high-brightness subject is detected in step S13 (step S13: No), the system control unit 16 erases the charge accumulated in the photodiode of each pixel and then performs the main exposure to capture a still image by simultaneous exposure (step S14). The system control unit 16 also performs a global transfer to read the charge accumulated in the photodiodes of multiple pixels by the main exposure to the charge holding unit simultaneously for all pixels.

[0062] Next, the system control unit 16 starts a readout process to sequentially read out the charge read out by the charge holding unit during this exposure as an image signal (step S15).

[0063] The system control unit 16 completes the readout process by sequentially reading the charge read out from the charge holding unit as an image signal for each pixel (step S16). The system control unit 16 does not perform defocus control if no high-brightness subject is detected.

[0064] Once the reading process is complete, the system control unit 16 records the image data of the still image captured in step S12 into the card storage unit 19 (step S17).

[0065] On the other hand, if a high-brightness subject is detected in step S13 (step S13: Yes), the system control unit 16 performs the main exposure after erasing the charge, similar to step S14 above (step S18). The system control unit 16 also performs a global transfer to read the charge into the charge holding unit simultaneously for all pixels.

[0066] Next, the system control unit 16 starts a readout process to sequentially read out the charge read out to the charge holding unit during this exposure as an image signal, and also performs defocus control to move the focus lens 12 to a defocus state (step S19). For example, the system control unit 16 moves the position of the focus lens 12 to a position shifted by a predetermined amount from the position at the time imaging was performed in step S12, for example, when the release button was pressed.

[0067] The system control unit 16 completes the readout process by sequentially reading the charge read out from the charge holding unit as an image signal for each pixel, and also performs focus recovery control to stop the defocus control and return the focus position to its original position (for example, the position at the time the release button was pressed) (step S20). Focus recovery control is an example of the second focus control of the present invention.

[0068] Once the reading process is complete and the transmittance is restored, the system control unit 16 records the image data of the still image capture performed in step S12 into the card storage unit 19 (step S17), and terminates the series of processes.

[0069] Thus, the system control unit 16 performs defocus control after the simultaneous readout control (first drive) of the image sensor 14, during the period (first period) in which the charge accumulated by simultaneous exposure is read from the charge holding unit. During simultaneous exposure, there is a high probability that the subject is in focus, so there is a high probability that the image will become defocused if the focus position is moved from that state. For this reason, by blurring the bright spots and reducing the intensity (maximum intensity) of the light received by the image sensor 14 in those areas, the generation of PLS ​​noise 53 can be suppressed. For example, if the PLS noise 53 can be suppressed to the extent that it does not saturate, it is possible to correct the PLS noise by image processing.

[0070] In the defocus control described, the configuration involves moving the position of the focus lens 12 by a predetermined amount, but the configuration is not limited to this. For example, the system control unit 16 may determine the amount of movement of the focus lens 12 in the defocus control based on image data (e.g., data from the through image) obtained by imaging performed before the simultaneous readout control (first drive) of the image sensor 14, and the result of distance measurement performed before the simultaneous readout control of the image sensor 14.

[0071] Distance measurement, for example, is distance measurement for autofocus performed in the imaging system 1 (e.g., distance measurement using the image plane phase difference method). For example, suppose the image sensor 14 has multiple distance measurement points. The system control unit 16 acquires the brightness of each distance measurement point (or its vicinity) based on the through image, acquires the distance measurement result corresponding to the position where the brightness is above a threshold, and determines the amount of movement of the focus lens 12 so that the focus is lost from the position indicated by the acquired distance measurement result. This allows the focus lens 12 to be moved so that the focus is lost from high-brightness subjects, resulting in a defocused state where bright spots are blurred.

[0072] <Modified Example 1 of Control Processing of System Control Unit 16 During Imaging> Figure 6 is a flowchart showing Modified Example 1 of Control Processing of System Control Unit 16 During Imaging. As shown in Figure 6, the processing from step S11 to step S17 is the same as the processing from step S11 to step S17 described in Figure 5.

[0073] In this modified example, if a high-luminance subject is detected in step S13 (step S13: Yes), the system control unit 16 determines whether the movement speed of the high-luminance subject is greater than or equal to a predetermined value (step S31). The movement speed of the high-luminance subject refers to the movement speed of the high-luminance subject within the captured image.

[0074] In step S31, if the movement speed of the high-brightness subject is not greater than or equal to a predetermined value (step S31: No), the system control unit 16 proceeds to step S14 and performs the main exposure to capture a still image. In other words, even if a high-brightness subject is detected, the system control unit 16 does not perform defocus control if the movement of the high-brightness subject is slow.

[0075] In step S31, if the movement speed of the high-brightness subject is greater than or equal to a predetermined value (step S31: Yes), the system control unit 16 proceeds to step S18 and performs the main exposure to capture a still image. That is, the system control unit 16 performs defocus control when a high-brightness subject is detected and the movement speed of that high-brightness subject is greater than or equal to a predetermined value.

[0076] When the detected high-brightness subject is moving slowly or is not moving, the superposition of bright spots of the high-brightness subject during the sequential readout process as an image signal has little effect on the generation of PLS ​​noise. Therefore, when the high-brightness subject is moving slowly or is not moving, defocus control is not performed. This allows the focus state of the through image to be maintained, making framing easier and improving exposure performance.

[0077] <Modified Example 2 of Control Processing of System Control Unit 16 During Imaging> Figure 7 is a flowchart showing modified example 2 of the control processing of the system control unit 16 during imaging. The processing shown in Figure 7 is the same as the processing shown in Figure 6, except for steps S19 and S20.

[0078] In step S19, the system control unit 16 performs aperture opening control along with the defocus control described above (step S19). Aperture opening control is a control that drives the aperture 13 in the direction of opening. For example, the system control unit 16 changes the state of the aperture 13 (e.g., F-number) in the direction of opening from the state at the time imaging was performed in step S12, for example, when the release button was pressed. As an example, the system control unit 16 sets the aperture 13 to the maximum open state (state with the smallest F-number) as aperture opening control. Aperture opening control is an example of the first aperture control of the present invention.

[0079] In step S20, the system control unit 16 performs aperture return control, which stops the aperture opening control and returns the aperture 13 to its original open state (for example, the state when the release button was pressed), along with the focus return control (step S20).

[0080] Thus, the system control unit 16 may perform aperture opening control along with defocus control during the period (first period) in which the charge accumulated by simultaneous exposure is read out from the charge holding unit, after the simultaneous readout control (first drive) in the image sensor 14. This makes the depth of field in imaging shallower and increases the blurring of bright spots due to defocus control. As a result, the generation of PLS ​​noise 53 can be further suppressed.

[0081] <Modification 3 of the control processing of the system control unit 16 during imaging> Figure 8 is a flowchart of modification 3 of the control processing of the system control unit 16 during imaging. The processing shown in Figure 8 is the same as the processing shown in Figure 7, except for steps S19 and S20.

[0082] In step S19, the system control unit 16 performs aperture reduction control instead of aperture opening control as shown in Figure 7 (step S19). Aperture reduction control is a control that drives the aperture 13 in the closing direction. For example, the system control unit 16 changes the open state of the aperture 13 from the state at the time imaging was performed in step S12, for example, when the release button was pressed, in the closing direction. As an example, the system control unit 16 sets the aperture 13 to the minimum open state (the state with the maximum F value) as aperture reduction control. Aperture reduction control is another example of the first aperture control of the present invention.

[0083] In step S20, the system control unit 16 performs aperture recovery control, which stops the aperture reduction control and returns the aperture 13 to its original open state (for example, the state when the release button was pressed), along with the focus recovery control described above (step S20).

[0084] Thus, the system control unit 16 may perform aperture reduction control along with defocus control during the period (first period) in which the charge accumulated by simultaneous exposure is read out from the charge holding unit, after the simultaneous readout control (first drive) in the image sensor 14. This further reduces the intensity of light received by the image sensor 14 and suppresses the generation of PLS ​​noise 53.

[0085] <Modification 4 of the control processing of the system control unit 16 during imaging> Figure 9 is a flowchart of modification 4 of the control processing of the system control unit 16 during imaging. The processing shown in Figure 9 is the same as the processing shown in Figure 5, except for steps S19 and S41. This processing is performed, for example, in continuous shooting mode, which repeatedly captures still images, or in video mode, which captures moving images.

[0086] In step S18, the system control unit 16 performs the main exposure and a global transfer to read the charge to the charge holding unit simultaneously for all pixels, and then sets a focus control amount according to the continuous shooting interval (step S41). The continuous shooting interval is the time interval between images, and is the reciprocal of the number of images taken per unit of time. That is, the continuous shooting interval is the time from when the image sensor 14 starts reading the charge from the charge holding unit immediately after simultaneous exposure until the next simultaneous exposure starts.

[0087] For example, the system control unit 16 refers to the continuous shooting speed set when the release button is pressed, and sets the focus control amount based on the referenced continuous shooting speed. The focus control amount is the amount of movement of the focus lens 12. For example, the system control unit 16 sets the focus control amount (the amount of movement of the focus lens 12) to decrease as the continuous shooting interval becomes shorter.

[0088] In step S19, the system control unit 16 performs defocus control to move the focus lens 12 using the focus control amount set in step S41 (step S19).

[0089] Note that the setting of the focus control amount based on the continuous shooting interval is not limited to immediately after the main exposure in step S18. For example, the system control unit 16 may set the focus control amount based on the continuous shooting interval before the release button is pressed.

[0090] Thus, the system control unit 16 may determine the focus control amount (the amount of movement of the focus lens 12) in the defocus control based on the time from when it starts reading the charge from the charge holding unit immediately after simultaneous exposure until the next simultaneous exposure begins. This allows the amount of movement of the focus lens 12 to be reduced when the time until the next simultaneous exposure begins is short, preventing a situation where the return of the focus lens 12 by the focus return control is not completed in time before the next simultaneous exposure begins. Therefore, the impact of defocus control on the next simultaneous exposure can be suppressed.

[0091] <Modification 5 of the control processing of the system control unit 16 during imaging> Figure 10 is a flowchart of modification 5 of the control processing of the system control unit 16 during imaging. The processing shown in Figure 10 is the same as the processing shown in Figure 7, except for steps S19 and S42. This processing is performed, for example, in continuous shooting mode, which repeatedly captures still images, or in video mode, which captures moving images.

[0092] In step S18, the system control unit 16 performs the exposure and a global transfer to read the charge to the charge holding unit simultaneously for all pixels, and then sets the focus control amount and aperture control amount according to the continuous shooting interval (step S42). The setting of the focus control according to the continuous shooting interval is the same as in step S41 shown in Figure 9.

[0093] The aperture control amount is the amount by which the aperture 13 is driven. For example, the system control unit 16 refers to the continuous shooting speed set when the release button is pressed, and sets the aperture control amount based on the referenced continuous shooting speed. For example, the system control unit 16 sets the amount by which the aperture 13 is driven to decrease as the continuous shooting interval becomes shorter.

[0094] In step S19, the system control unit 16 performs defocus control using the focus control amount set in step S42, and also performs aperture opening control using the aperture control amount set in step S42 (step S19).

[0095] Note that the setting of the focus control amount and aperture control amount based on the continuous shooting interval is not limited to immediately after the main exposure in step S18. For example, the system control unit 16 may set the focus control amount and aperture control amount based on the continuous shooting interval before the release button is pressed.

[0096] Furthermore, while Figure 7 describes the process of setting the aperture control amount (opening amount) according to the continuous shooting interval when performing aperture open control, as shown here, the process may also be applied to setting the aperture control amount (reducing amount) according to the continuous shooting interval when performing aperture reduction control, as shown in Figure 8.

[0097] Thus, the system control unit 16 may determine the focus control amount in defocus control and the aperture control amount in aperture opening control (or aperture closing control) based on the time from when it starts reading the charge from the charge holding unit immediately after simultaneous exposure until the next simultaneous exposure begins. This reduces the amount of movement of the focus lens 12 and the amount of drive of the aperture 13 when the time until the next simultaneous exposure begins is short, preventing situations where the return of the focus lens 12 by focus return control and the return of the state of the aperture 13 by aperture return control do not occur in time before the next simultaneous exposure begins. Therefore, the impact of defocus control and aperture opening control (or aperture closing control) on the next simultaneous exposure can be suppressed.

[0098] <Modified Example 6 of Control Processing of System Control Unit 16 During Imaging> Figure 11 is a flowchart showing modified example 6 of control processing of system control unit 16 during imaging. The processing shown in Figure 11 is the same as the processing shown in Figure 6, except for steps S19 and S20.

[0099] In step S19, the system control unit 16 executes the defocus control described above and starts vibration isolation control (step S19). Vibration isolation control is a control that operates the vibration isolation mechanism of the imaging system 1 to blur the image on the image sensor 14, and is an example of the first vibration isolation control of the present invention.

[0100] The image stabilization mechanism provided by the imaging system 1 is at least one of the following: a lens-type image stabilization mechanism (in-lens image stabilization mechanism) that suppresses image blur with respect to the image sensor 14 by moving the optical system included in the imaging lens 11, etc.; and a body-type image stabilization mechanism (in-body image stabilization mechanism) that suppresses image blur with respect to the image sensor 14 by moving the image sensor 14.

[0101] The vibration damping mechanism is provided for the purpose of blur correction to suppress image blur on the image sensor 14. However, the vibration damping control described above is a control that intentionally causes image blur on the image sensor 14 by driving the vibration damping mechanism in a manner different from that used to suppress image blur.

[0102] Furthermore, if the control of the image stabilization mechanism for the purpose of image correction is in progress, the image stabilization control may also involve stopping the control of the image stabilization mechanism for the purpose of image correction. In this case, by stopping the control of the image stabilization mechanism for the purpose of image correction, the image on the image sensor 14 can be blurred due to the user's hand tremor, etc.

[0103] In step S20, the system control unit 16 executes the focus recovery control described above and stops the vibration isolation control (step S20).

[0104] Thus, the system control unit 16 may, after the simultaneous readout control (first drive) of the image sensor 14, and during the period (first period) in which the charge accumulated by simultaneous exposure is read out from the charge holding unit, execute a vibration damping mechanism that blurs the image of the image sensor 14, along with defocus control. This further reduces the intensity of light received by the image sensor 14 and suppresses the generation of PLS ​​noise 53.

[0105] <Modification 7 of the control processing of the system control unit 16 during imaging> Figure 12 is a flowchart of modification 7 of the control processing of the system control unit 16 during imaging. The processing shown in Figure 12 is the same as the processing shown in Figure 6, except for steps S19 and S20.

[0106] In step S19, the system control unit 16 executes the defocus control described above and starts zoom control (step S19). Zoom control is a control that narrows the imaging area (the area that becomes the subject) by operating the zoom mechanism of the imaging system 1 to the telephoto side, and is an example of the first zoom control of the present invention.

[0107] The zoom mechanism of the imaging system 1 is a mechanism that changes the focal length of the entire optical system of the imaging system 1 by moving the zoom lens included in the imaging lens 11, etc.

[0108] The zoom mechanism is provided for the purpose of allowing the user to zoom (zoom in or zoom out) according to the intention to take an image. The above zoom control is a control that prevents bright spots from being imaged on the image sensor 14, in other words, moves the bright spots outside the frame, by changing the focal length of this zoom mechanism to a longer focal length (telephoto side) than the focal length set according to the intention to take an image.

[0109] In step S20, the system control unit 16 executes the focus recovery control described above and stops the zoom control (step S20).

[0110] Figure 13 shows an example of how the imaging area changes due to zoom control. Image formation state 61 is the imaging state in the imaging range 50 at the time the release button is pressed. In image formation state 61, the headlights 52 of the vehicle 51 are imaged in the imaging range 50, and the headlights 52 are high-brightness subjects.

[0111] Image formation state 62 is the image formation state in the imaging range 50 when zoom control is applied. In image formation state 62, the focal length is longer (zoomed in) compared to image formation state 61, so the high-brightness subject, the headlight 52, is not included in the imaging range 50.

[0112] Thus, the system control unit 16 may perform zoom control to move the zoom mechanism to the telephoto side, along with defocus control, during the period (first period) in which the charge accumulated by simultaneous exposure is read out from the charge holding unit after the simultaneous readout control (first drive) in the image sensor 14. This further reduces the intensity of light received by the image sensor 14 and suppresses the generation of PLS ​​noise 53.

[0113] <Modified Images of Imaging System 1> Figure 14 shows a modified image of imaging system 1. In Figure 14, parts that are the same as those shown in Figure 1 are denoted by the same reference numerals and their descriptions are omitted. As shown in Figure 14, imaging system 1 may also include an electronic ND (Neutral Density) filter 31 in addition to the configuration shown in Figure 1.

[0114] The electronic ND filter 31 can control the transmittance of light incident through the imaging lens 11. Furthermore, the electronic ND filter 31 may also allow for control of the transmittance of each area of ​​the electronic ND filter 31. The transmittance decreases as the filter density of the electronic ND filter 31 increases. The electronic ND filter 31 is a guest-host type electronic variable ND filter, for example, constructed using a guest-host (GH) type liquid crystal containing a dye (dichroic dye). Because the dichroic dye has different light absorption rates depending on the axial direction, when a voltage is applied to the liquid crystal, the liquid crystal molecules change their arrangement in response to the voltage, following the movement of the liquid crystal and creating both a transmittance state and an absorption (light-blocking) state.

[0115] The electronic ND filter 31 is a filter that adjusts only the amount of light without affecting color. The electronic ND filter 31 is positioned between the imaging lens 11 and the image sensor 14, close to the image sensor 14. In this example, the electronic ND filter 31 is provided between the aperture 13 and the image sensor 14.

[0116] The electronic ND filter 31 creates a transmission state and a light-blocking state based on the imaging control signal transmitted from the system control unit 16. The electronic ND filter 31 may also be capable of creating transmission and light-blocking states for any given area. Furthermore, the electronic ND filter 31 may be configured to be insertable and removable from the optical path of light incident through the imaging lens 11. Alternatively, a liquid crystal shutter may be used as a light control device instead of the electronic ND filter 31.

[0117] <Modification 8 of the control processing of the system control unit 16 during imaging> Figure 15 is a flowchart of modification 8 of the control processing of the system control unit 16 during imaging. The processing shown in Figure 15 is executed, for example, in the configuration of the imaging system 1 shown in Figure 13. The processing shown in Figure 15 is the same as the processing shown in Figure 6, except for steps S19 and S20.

[0118] In step S19, the system control unit 16 executes the defocus control described above and starts the transmittance reduction control (step S19). The transmittance reduction control is a control that reduces the transmittance of the electronic ND filter 31. For example, in the transmittance reduction control, the system control unit 16 controls the transmittance of the electronic ND filter 31 to the lowest transmittance. The lowest transmittance means setting the filter density to the maximum density and controlling the entire image to black.

[0119] In step S20, the system control unit 16 executes the focus recovery control described above and stops the zoom control (step S20).

[0120] Furthermore, in transmittance reduction control, the system control unit 16 may reduce the transmittance of only the high-brightness area of ​​the electronic ND filter 31, rather than reducing the transmittance of the entire electronic ND filter 31. For example, when the system control unit 16 detects a high-brightness subject by analyzing image data, it determines the high-brightness area of ​​the electronic ND filter 31 corresponding to the region where the high-brightness subject exists. Then, after simultaneous readout control, the system control unit 16 performs transmittance reduction control to lower the transmittance of the high-brightness area in the electronic ND filter 31.

[0121] <Regarding control based on readout signals> For example, the system control unit 16 may start defocus control based on a readout signal that instructs the image sensor 14 to read to the charge holding unit during simultaneous readout control. A "readout signal" is a signal that defines the timing of global transfer. The system control unit 16 acquires a readout signal from the image sensor 14 and performs defocus control in synchronization with it. The system control unit 16 immediately performs defocus control when it is time to read the charge to the charge holding unit. By synchronizing the readout timing for reading the charge to the charge holding unit with the timing of defocus control and linking the two processes, the processing can be simplified. Although defocus control has been described, the aperture opening control, aperture closing control, image stabilization control, zoom control, and transmittance reduction control described above may also be started based on a readout signal that instructs the image sensor 14 to read to the charge holding unit during simultaneous readout control.

[0122] In the above embodiments, a configuration was described in which defocus control is performed by moving the focus lens 12 to create a defocused state. However, the control is not limited to defocus control; any control that reduces the intensity of light received by the image sensor 14 by controlling at least one of the imaging lens (e.g., imaging lens 11 or focus lens 12) or the image sensor 14 is acceptable. By performing such control, the generation of PLS ​​noise 53 can be suppressed.

[0123] In this embodiment, each process is executed on any computer. Furthermore, any computer may execute these processes using a processor as hardware, a program as software, or a combination thereof. In that case, the processor is configured to work in cooperation with the program to execute the various processes in this embodiment, and can function as a unit or means in this embodiment. Also, the execution order of the processes by the processor is not limited to the order described and may be changed as appropriate. Any computer may be a general-purpose computer, a computer designed for a specific purpose, a workstation, or any other system capable of executing each process.

[0124] A processor may consist of one or more hardware components, and the type of hardware is not limited. For example, a processor may consist of programmable logic devices such as a CPU (Central Processing Unit), MPU (Micro Processing Unit), FPGA (Field Programmable Gate Array), dedicated circuits for executing specific processes such as an ASIC (Application Specific Integrated Circuit), a GPU (Graphic Processing Unit), or an NPU (Neural Processing Unit). Furthermore, the type of hardware may be a combination of different types of hardware. When multiple hardware components are configured to execute one or more processes of a processor, these multiple hardware components may reside in physically separate devices or in the same device. Furthermore, in any embodiment, the order of each process performed by the processor is not limited to the order described above and may be changed as appropriate. The hardware is composed of an electrical circuit (circuitry) or the like, which is a combination of circuit elements such as semiconductor elements.

[0125] Furthermore, the program may be firmware or software such as microcode. Alternatively, the program may be, for example, a group of program modules, each function of which may be implemented by a processor configured to perform its respective function. The program may be program code or multiple code segments stored on one or more non-temporary computer-readable media (e.g., storage media or other storage). The program may be divided and stored on multiple non-temporary computer-readable media located in physically separate devices. Program code or code segments may represent any combination of procedures, functions, subprograms, routines, subroutines, modules, software packages, classes, or instructions, data structures, or program statements. Program code or code segments may be connected to other code segments or hardware circuits by sending and receiving information, data, arguments, parameters, or memory contents.

[0126] This invention can also be applied to programs and program products.

[0127] Although various embodiments have been described above, it goes without saying that the present invention is not limited to these examples. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention. Furthermore, the components in the above embodiments may be combined in any way without departing from the spirit of the invention.

[0128] This application is based on a Japanese patent application (JP 2025-026606) filed on February 21, 2025, the contents of which are incorporated by reference within this application.

[0129] 10 Imaging device 11 Imaging lens 12 Focus lens 13 Aperture 14 Image sensor 15 Digital signal processing unit 16 System control unit 17 EVF 18 Display LCD 19 Card storage unit 20 Operation unit 31 Electronic ND filter 41 Control signal 42 Main exposure 43 Readout 47 Live view 50 Imaging range 51 Vehicle 52 Headlights 53 PLS noise 61, 62 Imaging state t1, t2, t3 Time

Claims

1. An imaging system comprising: an imaging lens including a focus lens; an image sensor having a plurality of pixels and capable of a first drive that reads the charge accumulated by the simultaneous exposure of the plurality of pixels into a charge holding unit; and a processor, wherein the processor performs a first focus control that moves the focus lens after the first drive and during a first period in which the charge is read from the charge holding unit.

2. An imaging system according to claim 1, wherein the processor performs the first focus control immediately after the first drive and during a first period in which the charge is read from the charge holding unit.

3. The imaging system according to claim 1, wherein the processor moves the focus lens by a predetermined amount in the first focus control.

4. The imaging system according to claim 3, wherein the processor, in the first focus control, causes the focus lens to move by a predetermined amount to defocus.

5. The imaging system according to claim 1, wherein the processor moves the focus lens in the first focus control based on image data obtained by imaging performed before the first drive and the result of distance measurement performed before the first drive.

6. An imaging system according to claim 1, wherein the processor performs a high-luminance subject detection process on image data obtained by imaging performed before the first drive, and performs the first focus control based on the result of the detection process.

7. The imaging system according to claim 6, wherein the processor performs the first focus control during the first period when the high-luminance subject is detected and the high-luminance subject is moving.

8. The imaging system according to claim 1, wherein the imaging lens includes an aperture, and the processor performs the first focus control and the first aperture control for driving the aperture during the first period.

9. The imaging system according to claim 8, wherein the processor drives the first aperture control in the direction of opening the aperture.

10. The imaging system according to claim 8, wherein the processor drives the aperture in the closing direction in the first aperture control.

11. An imaging system according to claim 1, wherein the processor determines the amount of movement of the focus lens in the first focus control based on the time from when the charge is read out from the charge holding unit until the simultaneous exposure is started.

12. An imaging system according to claim 8, wherein the processor determines the amount of movement of the focus lens in the first focus control and the amount of movement of the aperture in the first aperture control based on the time from the start of reading charge from the charge holding unit until the start of simultaneous exposure.

13. An imaging system according to claim 1, comprising a vibration isolation mechanism, wherein the processor performs first focus control and first vibration isolation control for controlling the vibration isolation mechanism during the first period.

14. An imaging system according to claim 13, wherein the first vibration isolation control is a control that operates the vibration isolation mechanism to cause the image to blur with respect to the image sensor.

15. An imaging system according to claim 1, wherein the imaging lens includes a zoom mechanism, and the processor performs, in the first period, a first focus control and a first zoom control for driving the zoom mechanism.

16. The imaging system according to claim 15, wherein the processor drives the zoom mechanism to the telephoto side in the first zoom control.

17. An imaging system according to any one of claims 1 to 16, wherein the processor performs a second focus control after the first period to return the position of the focus lens moved by the first focus control.

18. An imaging device comprising: an image sensor that performs imaging using an imaging lens including a focus lens, and which has a plurality of pixels and is capable of a first drive that reads the charge accumulated by the simultaneous exposure of the plurality of pixels into a charge holding unit; and a processor, wherein the processor performs a first focus control that moves the focus lens after the first drive and during a first period in which the charge is read from the charge holding unit.

19. A control method for an imaging apparatus comprising an imaging lens including a focus lens, an image sensor having a plurality of pixels and capable of a first drive that reads the charge accumulated by the simultaneous exposure of the plurality of pixels to a charge holding unit, and a processor, wherein the processor performs a first focus control that moves the focus lens after the first drive and during a first period in which the charge is read from the charge holding unit.

20. A control program that causes the processor of an imaging apparatus to perform a process to move the focus lens during a first period after the first drive and while the charge is being read from the charge holding unit, the processor of an imaging apparatus comprising an imaging lens including a focus lens, an image sensor having a plurality of pixels and capable of a first drive that reads the charge accumulated by the simultaneous exposure of the plurality of pixels to a charge holding unit, and a processor.

21. An imaging system comprising: an imaging lens; an image sensor having a plurality of pixels and capable of a first drive that reads the charge accumulated by the simultaneous exposure of the plurality of pixels into a charge holding unit; and a processor, wherein the processor reduces the intensity of light received by the image sensor by controlling at least one of the imaging lens or the image sensor after the first drive and during a first period in which the charge is read from the charge holding unit.

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