Imaging device and program

Abstract

This imaging device comprises: an acquisition unit that acquires a first frequency of a light source; and a display unit that selectably displays a plurality of shutter speeds that are integer multiples of a period corresponding to the first frequency acquired by the acquisition unit.

Description

Imaging device and program Incorporation by Reference

[0001] This application claims priority from Japanese Patent Application No. 2024-38240, filed on March 12, 2024, the contents of which are incorporated herein by reference.

[0002] The present invention relates to an imaging device and a program.

[0003] Imaging devices capable of capturing images with reduced flicker are known (see, for example, Patent Document 1). Conventionally, the appearance of flicker in captured images caused by light sources that flicker at high frequencies has been a problem.

[0004] Japanese Patent Application Laid-Open No. 2022-171438

[0005] The imaging device of the first disclosed technique has an acquisition unit that acquires a first frequency of a light source, and a display unit that selectably displays multiple shutter speeds that are integer multiples of a period corresponding to the first frequency acquired by the acquisition unit.

[0006] The imaging device of the second disclosed technique includes an acquisition unit that acquires a first frequency of a light source, and an imaging unit that images a subject based on multiple shutter speeds that are integer multiples of a period corresponding to the first frequency acquired by the acquisition unit.

[0007] The imaging device of the third disclosed technology has a memory unit that stores multiple shutter speeds that are integer multiples of a period corresponding to the frequency of a light source, and a control unit that selects a second shutter speed from among the multiple shutter speeds based on a first shutter speed obtained according to a shooting mode, and controls exposure based on the second shutter speed.

[0008] The program of the fourth disclosed technology causes a processor to execute an acquisition process for acquiring a first frequency of a light source, and a display process for selectively displaying multiple shutter speeds that are integer multiples of the period corresponding to the first frequency acquired by the acquisition process.

[0009] The program of the fifth disclosed technology causes a processor to perform a process of selecting a second shutter time from among a plurality of shutter times that are integer multiples of a period corresponding to the frequency of the light source, based on a first shutter time obtained according to the shooting mode, and a control process of controlling exposure based on the second shutter time.

[0010] FIG. 1 is a block diagram illustrating an example of a hardware configuration of an imaging device according to a first embodiment. FIG. 2 is an explanatory diagram illustrating an example of an image of a subject including a light source. FIG. 3 is an explanatory diagram illustrating an example of stripes caused by flicker. FIG. 4 is an explanatory diagram illustrating an example of a normal shutter time list. FIG. 5 is an explanatory diagram illustrating an example of a flicker reduction shutter time list. FIG. 6 is an explanatory diagram illustrating an example of a flicker reduction frequency setting shutter time list according to the first embodiment. FIG. 7 is an explanatory diagram illustrating an example of a flicker reduction mode setting when live view is used. FIG. 8 is an explanatory diagram illustrating an example of a flicker reduction mode setting when live view is not used. FIG. 9 is a block diagram illustrating an example of a functional configuration of an imaging device according to the first embodiment. FIG. 10 is an explanatory diagram illustrating Example 1 of a flicker reduction frequency setting shutter time list according to a second embodiment. FIG. 11 is an explanatory diagram illustrating Example 2 of a flicker reduction frequency setting shutter time list according to the second embodiment. FIG. 12 is a block diagram illustrating an example of a functional configuration of an imaging device according to a third embodiment. FIG. 13 is a flowchart illustrating an example of an imaging process procedure performed by the imaging device according to the third embodiment.

[0011] <Figure 1: Example of Hardware Configuration of Imaging Device> Figure 1 is a block diagram showing an example of the hardware configuration of an imaging device according to Example 1. The imaging device 100 is a device capable of capturing still images or moving images, and specifically, for example, a digital camera, a digital video camera, a smartphone, a tablet, a personal computer, or a game console. In Figure 1, a digital camera will be described as an example of an imaging device.

[0012] The imaging device 100 includes a processor 101, a storage device 102, a drive unit 103, an optical system 104, an imaging element 105, an AFE (Analog Front End) 106, an LSI (Large Scale Integration) 107, an operation device 108, a microphone 109, a sensor 110, a display device 111, a communication IF (Interface) 112, a speaker 113, a light source 114, and a bus 115. The processor 101, the storage device 102, the drive unit 103, the LSI 107, the operation device 108, the microphone 109, the sensor 110, the display device 111, the communication IF 112, the speaker 113, and the light source 114 are connected to the bus 115.

[0013] The processor 101 is a circuit configuration that controls the imaging device 100. The storage device 102 serves as a working area for the processor 101. The storage device 102 is a non-transitory or temporary recording medium that stores various programs and data. Examples of the storage device 102 include a read-only memory (ROM), a random access memory (RAM), a hard disk drive (HDD), and a flash memory. A plurality of storage devices 102 may be implemented in the imaging device 100, and at least one of the storage devices 102 may be detachable from the imaging device 100.

[0014] The drive unit 103 drives and controls the optical system 104. The drive unit 103 has a drive circuit 103a and a drive source 103b. The drive circuit 103a controls the drive source 103b in response to instructions from the processor 101. The drive source 103b is, for example, a motor, and, under the control of the drive circuit 103a, moves a zoom lens 141b and a focusing lens 141c in the optical system 104 in the optical axis direction and controls the opening and closing of the diaphragm 142.

[0015] The optical system 104 includes a plurality of lenses (a lens 141 a, a zooming lens 141 b, and a focusing lens 141 c) arranged in the optical axis direction, and an aperture 142. The optical system 104 collects subject light and outputs the collected light to the image sensor 105.

[0016] The image sensor 105 receives subject light from the optical system 104 and converts it into an electrical signal. The image sensor 105 may be, for example, an XY address type solid-state image sensor (e.g., a CMOS (Complementary Metal-Oxide Semiconductor)) or a progressive scan type solid-state image sensor (e.g., a CCD (Charge Coupled Device)).

[0017] A plurality of light-receiving elements (pixels) are arranged in a matrix on the light-receiving surface of the image sensor 105. A plurality of types of color filters, each of which transmits light of a different color component, are arranged in a predetermined color array (for example, a Bayer array) on the pixels of the image sensor 105. Therefore, each pixel of the image sensor 105 outputs an analog electrical signal corresponding to each color component through color separation by the color filter.

[0018] The AFE 106 is an analog front-end circuit that performs signal processing on an analog electrical signal from the image sensor 105. The AFE 106 sequentially performs gain adjustment of the electrical signal, analog signal processing (correlated double sampling, black level correction, etc.), A / D conversion processing, and digital signal processing (defective pixel correction, etc.) to generate RAW image data and output it to the LSI 107. The above-described drive unit 103, optical system 104, image sensor 105, and AFE 106 constitute an image sensor 120.

[0019] The LSI 107 is a circuit configuration that executes specific processes such as image processing such as color interpolation, white balance adjustment, edge enhancement, gamma correction, and gradation conversion, as well as encoding, decoding, compression / expansion, recording, and playback, on the RAW image data from the AFE 106. Specifically, the LSI 107 may be realized by a PLD (Programmable Logic Device) such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array).

[0020] The operation device 108 is used to input commands and data. Examples of the operation device 108 include various buttons including a release button, switches, dials, and a touch panel. The microphone 109 receives voice input and generates voice data.

[0021] The sensor 110 is a device that detects information, and includes, for example, an AF (Automatic Focus) sensor, an AE (Automatic Exposure) sensor, a gyro sensor, an acceleration sensor, a temperature sensor, etc. The display device 111 displays image data and a setting screen.

[0022] The display device 111 includes a rear monitor on the rear of the imaging device 100 and an electronic viewfinder. The communication IF 112 connects to a network and transmits and receives data. The speaker 113 outputs audio. The light source 114 emits light. The light source 114 may be a strobe or a projector.

[0023] The image capturing unit 120 receives light that is emitted from the light source 114 and reflected by the subject. Based on the phase difference between the light emitted from the light source 114 and the light reflected from the subject, the time of flight (time of flight) is measured to measure the distance between the image capturing device 100 and the subject (subject distance). The measurement of the subject distance is performed by the LSI 107 or the processor 101 that executes a program.

[0024] <Figure 2: Imaging of a Subject Including a Light Source> Figure 2 is an explanatory diagram showing an example of imaging of a subject including a light source. The light source 200 is a light-emitting body that blinks periodically, such as a digital signage or LED lighting fixture. Such light source 200 blinks at a frequency proportional to, for example, 60 Hz. More specifically, for example, the light source 200 is a light source that blinks at a frequency of several hundred Hz to several thousand Hz, and it is preferable that the blinking frequency be faster than conventional light sources that blink at 100 Hz or 120 Hz. (A) is an image 201 in which stripes 203 are generated due to flickering of the light source 200, and (B) is an image 202 in which the stripes 203 have disappeared.

[0025] <Fig. 3: Occurrence of Stripes 203 Due to Flicker> Fig. 3 is an explanatory diagram showing an example of occurrence of stripes 203 due to flicker. Fig. 3 shows a blinking cycle 301 of the light source 200, exposure 302 of the image sensor 105 due to a rolling shutter, exposure amount 303 for each pixel line of the image sensor 105, and an image 201 in which stripes 203 occur. Here, the exposure time of the image sensor 105 is assumed to correspond to 3 1 / 4 cycles.

[0026] In the exposure 302 of the image sensor 105, three periods of exposure and one-quarter period of exposure of only the dark portions are performed on pixel line 321. Three periods of exposure and one-quarter period of exposure of both the dark portions and the bright portions are performed on pixel line 322. Three periods of exposure and one-quarter period of exposure of only the bright portions are performed on pixel line 323.

[0027] As a result, the amount of exposure varies depending on the position of the pixel line on the image sensor 105. That is, among pixel lines 321 to 323, pixel line 321 has a low amount of exposure and pixel line 323 has a high amount of exposure. In the image 201, the portions of each pixel line on the image sensor 105 where the amount of exposure 303 is low become stripes 203.

[0028] If the exposure time is not an integer multiple of the period corresponding to the frequency, the fraction (1 / 4 period in FIG. 3 ) of the period will expose the bright portion or the dark portion of the blinking of the light source 200, which differs for each pixel line of the image sensor 151, and therefore the exposure amount 303 will change periodically in the readout direction, causing stripes 203 to appear in the image 201. In the case of the light source 200 shown in FIG. 2 , the DC component of the stripes 203 in the image 201 is proportional to the integer part (3 in FIG. 3 ) of the period included in the exposure time of one pixel line, and the AC component is proportional to the decimal part (1 / 4 in FIG. 3 ).

[0029] <Shutter Time List> Next, the shutter time list will be described. A shutter time list is information that lists shutter times. In this example, the image capture device 100 has three types of shutter time lists. Specifically, for example, the image capture device 100 has three types of shutter time lists: a normal shutter time list that does not reduce flicker ( FIG. 4 ), a shutter time list for flicker reduction ( FIG. 5 ), and a shutter time list with a flicker reduction frequency setting ( FIG. 6 ). These lists are stored in the storage device 102. The image capture device 100 uses one of these three lists depending on the mode selected.

[0030] (FIG. 4: Normal Shutter Time List) FIG. 4 is an explanatory diagram showing an example of a normal shutter time list. The normal shutter time list 400 is a list that is selected when the flicker reduction function of the imaging device 100 is OFF. The normal shutter time list 400 is table data that associates a TV value 401, a shutter time 402, whether or not to accept 1 stop 403, whether or not to accept 1 / 3 stop 404, and whether or not to accept 1 / 2 stop 405.

[0031] The TV value 401 is a logarithm with a base of 2 and the denominator of the shutter speed 402 (a fraction with a numerator of 1) being the antilogarithm, and is treated as a step number. Therefore, the shorter the shutter speed 402, the larger the TV value 401, and the longer the shutter speed 402, the smaller the TV value 401. The shutter speed 402 is the exposure time for which the image sensor 151 is exposed. When a desired shutter speed is selected from the normal shutter speed list 400 by user input, the image capturing device 100 captures an image at the selected shutter speed.

[0032] The one-step adoption / non-adoption 403 is an identifier indicating whether the TV value 401 has been adopted in one-step steps. A circle indicates adoption. Specifically, for example, the TV value 401 in one-step increments is adopted in one-step steps with the TV value 401 "0" as the reference.

[0033] The 1 / 3 stop adoption / non-adoption 404 is an identifier indicating whether the TV value 401 has been adopted in 1 / 3 stop steps. A circle indicates that it has been adopted. Specifically, for example, the TV value 401 in 1 / 3 stop increments is adopted in 1 / 3 stop steps with the TV value 401 "0" as the reference.

[0034] The 1 / 2-stop adoption / non-adoption 405 is an identifier indicating whether the TV value 401 has been adopted in 1 / 2-stop steps. A circle indicates that it has been adopted. Specifically, for example, the TV value 401 in 1 / 2-stop increments is adopted in 1 / 2-stop steps with the TV value 401 "0" as the reference.

[0035] (FIG. 5: Flicker Reduction Shutter Time List) FIG. 5 is an explanatory diagram showing an example of a flicker reduction shutter time list. The flicker reduction shutter time list 500 is a list that can be selected when the flicker reduction function of the image capture device 100 is ON. The flicker reduction shutter time list 500 is table data that associates TV values ​​401 with shutter times 402. The TV value 501 is a logarithm with a base of 2 and the antilogarithm of the shutter time 502 (expressed as a fraction with a numerator of 1) as the denominator, and is treated as a step number. Therefore, the shorter the shutter time 502, the larger the TV value 501, and the longer the shutter time 502, the smaller the TV value 501. The shutter time 502 is the exposure time for which the image capture element 151 is exposed.

[0036] Flicker reduction shutter time list 500 is a list in which the TV value 401 in the range of [5 to 13] is highly resolved from normal shutter time list 400. That is, when TV value 501 is in the range of [11 to 13], it is in 1 / 16-stop steps, and when it is in the range of [5 to 11], it is in 1 / 96-stop steps, but flicker reduction shutter time list 500 contains a mixture of shutter times 502 that cause stripes 203 to appear and shutter times 502 that do not cause stripes 203 to appear.

[0037] When the user operates and selects a desired shutter speed from the flicker reduction shutter speed list 500, the imaging device 100 captures an image at the selected shutter speed. The flicker reduction shutter speed list 500 has higher resolution than the normal shutter speed list 400, and can therefore detect a shutter speed 502 that does not produce stripes 203 with higher accuracy than the normal shutter speed list 400. However, because there are more shutter speeds to be detected, there is a concern that it may take a long time for the user to operate the list and find the appropriate shutter speed 502, resulting in the user missing a good photo opportunity.

[0038] (FIG. 6: Flicker Reduction Frequency Setting Shutter Time List) FIG. 6 is an explanatory diagram showing an example of a flicker reduction frequency setting shutter time list according to Example 1. The flicker reduction frequency setting shutter time list 600 is a list that can be selected when the flicker reduction function of the imaging device 100 is ON. The flicker reduction frequency setting shutter time list 600 is table data that associates integer multiples of one period 601, shutter times 602, relative step numbers 603, adoption / non-adoption of 1 / 3 step 604, and adoption / non-adoption of 1 / 2 step 605.

[0039] 6 shows an example in which the preset frequency, which is the refresh rate at which the light source 200 blinks, is set to 3840 Hz. The integer multiples 601 of one period are integers in ascending order starting from 1 (period), where one period is a preset period (1 / 3840 [s]), which is the reciprocal of the preset frequency.

[0040] The shutter time 602 is the exposure time for which the image sensor 151 is exposed, and is the reciprocal of the value obtained by dividing the preset frequency by an integer multiple 601 of one cycle. The shutter time 602 matches the blinking cycle of the light source 200; that is, there is no fractional cycle (1 / 4 cycle in FIG. 3 ). Therefore, when exposure is performed at the shutter time 602, the amount of exposure is uniform for all pixel lines 321 to 323, and stripes 203 do not appear in the image 201.

[0041] The relative step number 603 is a relative step number expressed as a logarithm to the base 2 of the amount of change in the shutter speed 602 from the reference value for each b (integer multiple 601 of one cycle) of the shutter speed 602 "1 / 3840 [s]," with b=1 as the reference value. Therefore, the higher the relative step number 603, the longer the shutter speed 602. When the relative step number 603 is selected in one-step increments, shutter speeds 602 for which the relative step number 603 is an integer (0.000, 1.000, 2.000, ...) can be selected. When the desired shutter speed 602 is selected from the flicker reduction frequency setting shutter speed list 600 by user input, the imaging device 100 captures an image at the selected shutter speed.

[0042] The 1 / 3 step adoption / non-adoption 604 is an identifier indicating whether the relative step number 603 has been adopted in 1 / 3 step steps. A circle indicates that it has been adopted. The rule for the 1 / 3 step adoption / non-adoption 604 is that for relative step numbers 603 between consecutive integers, the relative step number 603 whose difference between the decimal part and 1 / 3 or 2 / 3 is the smallest is adopted.

[0043] Note that for rows where the integer multiple of one period 601 is 1 to 8, the amount of change in the relative step number 603 relative to a change in the integer b is large, so rows where the integer multiple of one period 601 is 6 or 7 are unconditionally adopted in the 1 / 3 step adoption / rejection 604. That is, in the high-speed band where the integer multiple of one period 601 is 1 to 8, all of these shutter speeds 602 are displayed as selectable, but this is not limiting, and they may also be displayed as selectable according to the 1 / 3 step adoption / rejection 604.

[0044] Between the relative step numbers 603 of "3.000" and "4.000", there are the relative step numbers 603 of "3.170", "3.322", "3.459", "3.585", "3.700", "3.807", and "3.907". Of these, the relative step number 603 whose decimal part is closest to 1 / 3 (≒ 0.333) is "3.322", so "3.322" is adopted as the 1 / 3 step. Similarly, the relative step number 603 whose decimal part is closest to 2 / 3 (≒ 0.667) is "3.700", so "3.700" is adopted as the 1 / 3 step. The same method is used to determine whether or not to adopt the relative step number 603 of "4.000" and above.

[0045] The 1 / 2 step adoption / non-adoption 605 is an identifier indicating whether the relative step number 603 has been adopted in 1 / 2 step steps. A circle indicates that it has been adopted. The rule for the 1 / 2 step adoption / non-adoption 605 is that for relative step numbers 603 between consecutive integers, the relative step number 603 whose difference between the decimal part and 1 / 2 is the smallest is adopted.

[0046] Note that for rows where the integer multiple of one period 601 is 1 to 8, the amount of change in the relative step number 603 relative to a change in the integer b is large, so rows where the integer multiple of one period 601 is 5 or 7 are unconditionally adopted for the 1 / 2 step adoption / rejection 605. That is, in the high-speed band where the integer multiple of one period 601 is 1 to 8, all of these shutter speeds 602 are displayed as selectable, but this is not limiting, and they may be displayed as selectable according to the 1 / 2 step adoption / rejection 605.

[0047] Between the relative step numbers 603 of "3.000" and "4.000", there are the relative step numbers 603 of "3.170", "3.322", "3.459", "3.585", "3.700", "3.807", and "3.907". Of these, the relative step number 603 whose decimal part is closest to 1 / 2 (=0.500) is "3.459", so "3.459" is adopted as the 1 / 2 step. The same method is used to determine whether or not to adopt the relative step number 603 of "4.000" and above.

[0048] In this way, when the integer multiple 601 of one cycle is 5 or greater, multiple shutter speeds 602 are displayed so that the integer multiples 601 of one cycle are not consecutive. In this way, by using intervals so that the shutter speeds 602 are not consecutive using the 1 / 3 stop selection / rejection 604 and 1 / 2 stop selection / rejection 605, the hassle of selecting the shutter speed 602 is reduced.

[0049] That is, the larger the period b, which is the value of the integer multiple 601 of one period, the smaller the amount of change in the relative step number 603 when b=n and when b=n+1 (n is a positive integer). If all shutter speeds 602 corresponding to integer multiples 601 of one period were selectable, the amount of change in the amount of light relative to the amount of user operation would decrease as period b increased, making adjustment cumbersome. By allowing selection in 1 / 3-stop and 1 / 2-stop steps, the user can make the desired adjustment even when period b is large.

[0050] Furthermore, imaging devices are generally known that allow adjustment of the amount of change in the relative shutter speed 603, based on the shutter speed 602 = 1 second, in 1-stop steps, 1 / 3-stop steps, or 1 / 2-stop steps when the normal shutter speed 602 is selected. In Example 1, adjustment is possible in 1-stop steps, 1 / 3-stop steps, or 1 / 2-stop steps even in the flicker reduction mode, just as when the normal shutter speed 602 is selected, so the user can operate the device with the same feel as before, even in the flicker reduction mode.

[0051] Therefore, the user can easily make a selection during operation, and no matter which shutter time 602 is selected, the selected shutter time 602 is an integer multiple 601 of one period, so that stripes 203 do not appear in the image 201.

[0052] 6, the preset frequency in the flicker reduction frequency setting shutter speed list 600 is set to 3840 Hz, but multiple preset frequencies (for example, 7680 Hz, 2880 Hz, and 1920 Hz) may be provided. In this case, an integer multiple of one period 601, a 1 / 3 step adoption / rejection 604, and a 1 / 2 step adoption / rejection 605 are stored in the storage device 102 as a lookup table.

[0053] The integer multiple of one period 601, the ⅓ stop adoption / non-adoption 604, and the ½ stop adoption / non-adoption 605 do not depend on the preset frequency. Once the preset frequency is set, the imaging device 100 can refer to a lookup table stored in the storage device 102 and calculate a shutter speed 602 that allows flicker reduction. However, the flicker reduction frequency setting shutter speed list 600 may be stored in the storage device 102 for each preset frequency.

[0054] The user can select the shutter speed 602 in 1-stop steps, 1 / 3-stop steps, or 1 / 2-stop steps. In 1-stop steps, the shutter speed 602 can be changed in 1-stop steps, in 1 / 3-stop steps, the shutter speed 602 can be changed in 1 / 3-stop steps, and in 1 / 2-stop steps, the shutter speed 602 can be changed in 1 / 2-stop steps. However, in all 1-stop steps, 1 / 3-stop steps, and 1 / 2-stop steps, the user can select shutter speeds 602 where the integer multiple 601 of one period is 1 to 4.

[0055] Also, in FIG. 6, the shutter speed 602 is described as being in 1-stop steps, 1 / 3-stop steps, and 1 / 2-stop steps, but it may also be set in other step numbers, such as 1 / 4-stop steps, 1 / 5-stop steps, etc.

[0056] <Setting of Flicker Reduction Mode> Next, setting of the flicker reduction mode will be described. The flicker reduction mode is a mode that is set when the flicker reduction function of the imaging device 100 is set to ON.

[0057] (FIG. 7 Example of Setting Flicker Reduction Mode When Live View is Used) FIG. 7 is an explanatory diagram showing an example of setting the flicker reduction mode when live view is used according to Example 1. The display device 111 displays a display screen including an upper edge display area 701, a lower edge display area 702, and a central display area 703.

[0058] The frequency setting information 700 is information for selecting a plurality of flicker reduction frequency setting shutter time lists 600 and flicker reduction shutter time lists 500 , and for selecting the shutter times 502 and 602 .

[0059] In the frequency setting information 700, a plurality of preset frequencies PRE1 to PRE4 and "OFF," which indicates that no frequency is set, can be selected using a sub-command dial, which is an example of the operation device 108. The selected item is displayed in the upper edge display area 701. In the example of FIG. 7, "PRE1" has been selected, so "PRE1" is displayed in the upper edge display area 701, and "7680.0 Hz," which is the preset frequency of "PRE1," is displayed in the lower edge display area 702.

[0060] The flicker reduction frequency setting shutter time lists 600 based on each of the preset frequencies PRE1 to PRE4 are referred to as flicker reduction frequency setting shutter time lists 600-1 to 600-4. The flicker reduction frequency setting shutter time list 600 shown in Figure 6 is the flicker reduction frequency setting shutter time list 600-2. Also, "OFF" indicates the flicker reduction shutter time list 500.

[0061] The shutter speeds 502 and 602 can be selected with the main command dial, which is an example of the operation device 108. In FIG. 7, because "PRE1" was selected, the shutter speed 602 in the flicker reduction frequency setting shutter speed list 600-1 can be selected, and in this case, because the shutter speed 602 "1 / 1920.0" was selected with the main command dial, the denominator "1920.0" of the shutter speed 602 "1 / 1920.0" is displayed in the bottom edge display area 702.

[0062] A live view of the subject image is displayed in the central display area 703. When an actual image is captured, the captured image is also displayed. In Fig. 7, an image 202 without stripes 203, exposed at the selected shutter speed 602 "1 / 1920.0", is displayed.

[0063] (FIG. 8: Example of Setting Flicker Reduction Mode When Live View Is Not Used) FIG. 8 is an explanatory diagram showing an example of setting the flicker reduction mode when live view is not used according to Example 1. A first flicker reduction function screen 801 is selected from a menu screen (not shown) and is displayed in the central display area 703 of the display device 111.

[0064] [Flicker reduction function first screen 801] The flicker reduction function first screen 801 displays a use selection button 811, a non-use selection button 812, and an OK button 813. When the use selection button 811 is selected and the OK button 813 is also selected, the display content of the central display area 703 transitions from the flicker reduction function first screen 801 to the flicker reduction function second screen 802. In this case, the flicker reduction function is set to ON.

[0065] On the other hand, when the non-use selection button 812 is selected and the OK button 813 is also selected, the display content of the central display area 703 transitions from the flicker reduction function first screen 801 to a screen displaying the normal shutter time list 400. In this case, the flicker reduction function is OFF. Therefore, the user operates the operation device 108 to select the shutter time 402 from the normal shutter time list 400, and the imaging device 100 captures an image using the selected shutter time 402.

[0066] [Flicker reduction function second screen 802] The flicker reduction function second screen 802 displays a preset frequency PRE1 selection button 821, a preset frequency PRE2 selection button 822, a preset frequency PRE3 selection button 823, a preset frequency PRE4 selection button 824, a frequency non-setting button 825, an OK button 826, and a modify button 827.

[0067] The preset frequency PRE1 selection button 821 to the preset frequency PRE4 selection button 824 are user interfaces for selecting the preset frequencies PRE1 to PRE4. The frequency no-setting button 825 is a user interface for selecting "OFF" which indicates that no frequency is set.

[0068] When the frequency non-setting button 825 is selected and the OK button 826 is also selected, the display content of the central display area 703 transitions from the first flicker reduction function screen 801 to a screen displaying the flicker reduction shutter time list 500. Therefore, the user operates the operation device 108 to select the shutter time 502 from the flicker reduction shutter time list 500, and the imaging device 100 captures an image using the selected shutter time 502.

[0069] When any of the preset frequency PRE1 selection button 821 to the preset frequency PRE4 selection button 824 is selected and the OK button 826 is selected, the display content of the central display area 703 transitions from the second flicker reduction function screen 802 to the third flicker reduction function screen 803.

[0070] When any of the preset frequency PRE1 selection button 821 to the preset frequency PRE4 selection button 824 is selected and the correction button 827 is selected, the display content of the central display area 703 transitions from the second flicker reduction function screen 802 to the fourth flicker reduction function screen 804.

[0071] When the browser back button 829 is selected, the display content of the central display area 703 transitions from the second flicker reduction function screen 802 to the previous screen, for example, the first flicker reduction function screen 801 .

[0072] [Flicker reduction function third screen 803] The flicker reduction function third screen 803 displays the flicker reduction frequency setting shutter time list 600 corresponding to the preset frequency selected on the flicker reduction function second screen 802. In Fig. 8, as an example, it is assumed that the preset frequency PRE1 (7680 Hz) is selected on the flicker reduction function second screen 802. Therefore, the shutter time 602 of the flicker reduction frequency setting shutter time list 600-1 is displayed in a selectable manner in the central display area 703.

[0073] The scroll button 830 is a user interface for scrolling up and down the shutter speed 602. When the up scroll button 831 is selected, the row of shutter speeds 602 scrolls up, and long shutter speeds 602 appear. When the down scroll button 832 is selected, the row of shutter speeds 602 scrolls down, and short shutter speeds 602 appear.

[0074] When one of the shutter speeds 602 is selected and the OK button 833 is selected, exposure can be performed at the selected shutter speed 602. Therefore, the imaging device 100 captures an image using the selected shutter speed 602, and an image 202 without stripes 203 can be obtained.

[0075] When the Modify button 834 is selected, the display content of the central display area 703 changes from a third flicker reduction function screen 803 to a fourth flicker reduction function screen 804 .

[0076] When the browser back button 835 is selected, the display content of the central display area 703 transitions from the third flicker reduction function screen 803 to the previous screen, for example, the second flicker reduction function screen 802 .

[0077] [Fourth Flicker Reduction Function Screen 804] The fourth flicker reduction function screen 804 is a screen for modifying the selected preset frequency (in this example, the preset frequency PRE1 (7680 Hz)). The fourth flicker reduction function screen 804 displays integer first digit 841 to integer fourth digit 844 indicating each digit of the preset frequency, scroll buttons 845 (up scroll button 846, down scroll button 847), an OK button 848, and a browser back button 849.

[0078] The scroll button 845 is a user interface for scrolling the integer in the corresponding digit up and down. In FIG. 8 , the scroll button 845 is located at the second integer digit 842, so the second integer digit 842 can be changed. When the up scroll button 846 is selected, the integer in the corresponding digit counts up, and when the down scroll button 847 is selected, the integer in the corresponding digit counts down. The example in FIG. 8 indicates that the preset frequency PRE1 (7680 Hz) has been changed to 7630 Hz. The scroll button 845 can be moved left and right to select a digit using the operation device 108.

[0079] When the browser back button 849 is selected, the display content of the central display area 703 transitions from the fourth flicker reduction function screen 804 to the previous screen, for example, the second flicker reduction function screen 802 or the third flicker reduction function screen 803.

[0080] When the OK button 848 is selected, the imaging device 100 creates a flicker reduction frequency setting shutter time list 600 based on the frequency (7630 Hz in this example) set in the first integer digit 841 to the fourth integer digit 844 at the time of selection, and stores the list in the storage device 102. The display content of the central display area 703 then transitions from the fourth flicker reduction function screen 804 to the third flicker reduction function screen 803, which displays the newly created flicker reduction frequency setting shutter time list 600.

[0081] (Creating a new flicker reduction frequency setting shutter speed list 600) Here, we will explain how to create a flicker reduction frequency setting shutter speed list 600 based on the frequency changed on the flicker reduction function fourth screen 804 (7630 Hz in this example).

[0082] The imaging device 100 uses the changed frequency (7630 Hz in this example) as a reference and associates the changed period a, which is the reciprocal of the changed frequency, with the value b=1 of the integer multiple of one period 601 and the value "0.000" of the relative step number 603. The imaging device 100 calculates the value of the relative step number 603 by log ２The imaging apparatus 100 also calculates the shutter speed 602 at the value b of the integer multiple 601 of one period by multiplying the changed period a by the value b.

[0083] Furthermore, for the adoption / non-adoption 604 of 1 / 3 stop at each shutter speed 602 after the value b=5 of the integer multiple 601 of one period, the imaging device 100 adopts the relative step number 603 that minimizes the difference between the decimal part of the relative step number 603 and 1 / 3 or 2 / 3. Similarly, for the adoption / non-adoption 604 of 1 / 2 stop at each shutter speed 602 after the value b=5 of the integer multiple 601 of one period, the imaging device 100 adopts the relative step number 603 that minimizes the difference between the decimal part of the relative step number 603 and 1 / 2. In this way, a new flicker reduction frequency setting shutter speed list 600 is created for the changed frequency.

[0084] It should be noted that a unique name, such as PRE5, is automatically assigned to the new flicker reduction frequency setting shutter time list 600. In the following description, the new flicker reduction frequency setting shutter time list 600 will be referred to as flicker reduction frequency setting shutter time list 600-5.

[0085] 9 is a block diagram illustrating an example of a functional configuration of the imaging device 100 according to Example 1. The imaging device 100 includes an imaging unit 120, a storage unit 900, an acquisition unit 901, a display unit 902, a determination unit 903, a calculation unit 904, an input unit 905, a selection unit 906, and an image processing unit 907.

[0086] The storage unit 900 is specifically realized by, for example, the storage device 102 shown in Fig. 1. The acquisition unit 901, the display unit 902, the determination unit 903, the calculation unit 904, the input unit 905, the selection unit 906, and the image processing unit 907 are specifically realized by, for example, causing the processor 101 to execute a program stored in the storage device 102 shown in Fig. 1, or by the LSI 107.

[0087] The storage unit 900 stores a normal shutter time list 400 , a flicker reduction shutter time list 500 , and a flicker reduction frequency setting shutter time list 600 .

[0088] The acquisition unit 901 acquires the first frequency of the light source 200. The first frequency of the light source 200 is, for example, a preset frequency in the flicker reduction frequency setting shutter speed list 600 that is selected by the user operating the operation device 108. Alternatively, the first frequency of the light source 200 may be, for example, a frequency that is input by the user operating the operation device 108.

[0089] Furthermore, the first frequency of light source 200 may be a frequency detected by imaging device 100. For example, the sum of luminance values ​​is calculated for each pixel line in consecutive images A and B in which flickering occurs. The first frequency of light source 200 can be calculated by calculating the difference between the sum of luminance values ​​for each pixel line in images A and B and analyzing the difference.

[0090] Furthermore, the imaging device 100 may calculate the sum of the luminance values ​​of the pixel lines described above for each of multiple pixel lines, for example, the sum of two pixel lines. The sum of the luminance values ​​of the pixel lines may also be calculated for some of the pixel lines. Furthermore, the imaging device 100 may perform analysis using an average value of the luminance values, rather than using the sum of the luminance values ​​of the pixel lines. Furthermore, the imaging device 100 may be provided with a sensor for detecting flicker, and the imaging device 100 may detect the first frequency of the light source 200 using the sensor. Furthermore, the imaging device 100 may detect flicker using another sensor.

[0091] The display unit 902 selectably displays on a display screen a plurality of shutter speeds 602 that are integer multiples 601 of one period corresponding to the first frequency acquired by the acquisition unit 901. The display screen is, for example, a screen displayed on a rear monitor or electronic viewfinder, which is the display device 111. Specifically, the display unit 902 displays the screens shown in FIGS. 7 and 8, for example.

[0092] The determination unit 903 determines whether the first frequency and the second frequency match. The second frequency is one of the preset frequencies PRE1 to PRE5 set in the flicker reduction frequency setting shutter speed lists 600-1 to 600-5 stored in the storage unit 900.

[0093] In this case, the display unit 902 displays a plurality of shutter speeds 602 in a selectable manner based on the determination result by the determination unit 903. Specifically, for example, when the determination unit 903 determines that the first frequency and the second frequency match, if the second frequency is the preset frequency PRE1, the display unit 902 displays a plurality of shutter speeds 602 in the flicker reduction frequency setting shutter speed list 600-1 in a selectable manner.

[0094] When the determination unit 903 determines that the first frequency and the second frequency do not match, the calculation unit 904 calculates a plurality of shutter speeds 602 that are integer multiples 601 of one period corresponding to the first frequency. Specifically, for example, as described above, if the first frequency is the changed frequency (for example, 7630 Hz), the calculation unit 904 associates the changed period a, which is the reciprocal of the first frequency, with the value of the integer multiple 601 of one period, "1," and the value of the relative step number 603, "0.000," and sets the value of the integer multiple 601 of one period to b, and calculates the value of the relative step number 603 by log ２ Calculate using b.

[0095] The calculation unit 904 also calculates the shutter speed 602 at the value b of the integer multiple 601 of one period by dividing the changed period a by b. The calculation unit 904 also determines whether to adopt 1 / 3 stop 604 and whether to adopt 1 / 2 stop 604, as described above. As a result, a flicker reduction frequency setting shutter speed list 600-5 is created and stored in the storage unit 900.

[0096] The display unit 902 then displays a plurality of selectable shutter times 602 calculated by the calculation unit 904. Specifically, for example, the display unit 902 displays the shutter times 602 in the flicker reduction frequency setting shutter time list 600-5 on the screen as shown in FIGS.

[0097] The input unit 905 accepts input for changing the first frequency. Specifically, for example, as described with respect to the fourth flicker reduction function screen 804 in Fig. 8 , the input of the changed first frequency (7630 Hz in Fig. 8 ) is accepted. In this case, the determination unit 903 determines whether the changed first frequency and the second frequency match.

[0098] The selection unit 906 accepts the selection of any one of the shutter times 602 from the plurality of shutter times 602. For example, as shown in FIG. 7 , the selection unit 906 accepts the selection of any one of the shutter times 602 in the flicker reduction frequency setting shutter time list 600-1 using the main command dial.

[0099] When one of the shutter speeds 602 is selected by the selection unit 906 , the image capturing unit 120 captures an image of the subject at the selected shutter speed 602 .

[0100] Furthermore, when the acquisition unit 901 acquires the first frequency, the image capturing unit 120 captures an image of the subject based on a plurality of shutter times 602 that are integer multiples 601 of one period corresponding to the first frequency. For example, assume that the shutter time 602 in the flicker reduction frequency setting shutter time list 600-2 is set to "1 / 3840." In this case, when the user operates the operation device 108, the image capturing unit 120 captures an image of the subject at the shutter time 602 "1 / 3840."

[0101] The image processing unit 907 executes image processing based on the image data output from the imaging unit 120. As a result, the display unit 902 displays the images 201 and 202 that have been subjected to image processing by the image processing unit 907 in the central display area 703.

[0102] The display unit 902 displays images 201 and 202 in the central display area 703, but may also display image 201 in which stripes 203 occur, obtained without using the flicker reduction frequency setting shutter speed list 600, and image 202 in which stripes 203 do not occur, obtained using the flicker reduction frequency setting shutter speed list 600.

[0103] Specifically, for example, the display unit 902 may display the images 201 and 202 in a split manner in the central display area 703 of the rear monitor, or may display the images 201 and 202 in a split manner in the central display area 703 of the electronic viewfinder. Furthermore, the display unit 902 may display the image 201 in the central display area 703 of one of the display devices 111, the rear monitor and the electronic viewfinder, and display the image 202 in the central display area 703 of the other display device 111. This allows the user to view the images 201 and 202 and compare the extent to which the stripes 203 are generated.

[0104] Next, a description will be given of Example 2. In Example 1, as shown in Fig. 6, the shutter speed 602 is determined by the integer multiple 601 of one period. That is, in Fig. 6, the value b of the integer multiple 601 of one period is a continuous value, and from the relative step numbers 603 corresponding to each value b, it is possible to select the shutter speed 602 of the relative step number 603 that is close to a constant multiple of a predetermined step number.

[0105] In contrast, in Example 2, a value b is set when the shutter speed is a constant multiple of a predetermined number of steps, and the shutter speed corresponding to this value b can be selected. Example 2 shows an example in which the shutter speed is determined by another method. Note that in Example 2, differences from Example 1 will be mainly described, and therefore descriptions of common parts with Example 1 will be omitted.

[0106] (FIGS. 10 and 11: Flicker Reduction Frequency Setting Shutter Time List) FIG. 10 is an explanatory diagram showing Example 1 of a flicker reduction frequency setting shutter time list according to Example 2. A flicker reduction frequency setting shutter time list 1000 is set in the imaging device 100 in place of the flicker reduction frequency setting shutter time list 600.

[0107] The flicker reduction frequency setting shutter speed list 1000 has 1 / 3 stop steps 1001, integer multiples of one cycle 601, and shutter speed 602. The 1 / 3 stop steps 1001 are relative step numbers adopted in the 1 / 3 stop adoption / rejection 604. When the 1 / 3 stop steps 1001 are 3 or less, the step number changes roughly, so the values ​​are the same as those shown in FIG. 6. When the 1 / 3 stop steps 1001 are relative step numbers greater than 3.000, the 1 / 3 stop steps 1001 are set in 1 / 3 stop increments.

[0108] For example, the value b of the integer multiple 601 of one period corresponding to 3+1 / 3 (=3.333333) steps in the 1 / 3 step step 1001 is 2^(3+1 / 3)=10.07937, and is set to the nearest integer, b=10.

[0109] The shutter speed 602 at this time is calculated as 1 / preset frequency (for example, 3840 [Hz])×b, which is 1 / 384 [s].

[0110] When the 1 / 3 step 1001 is 3 + 2 / 3 (= 3.66667), 2^(3 + 2 / 3) = 12.69921, and b is set to 13. The shutter speed 602 at this time is calculated as 1 / preset frequency (for example, 3840 [Hz]) × b, which is 1 / 295.3846154 [s].

[0111] When the 1 / 3 step step 1001 is 3 + 3 / 3 (= 4), 2^(4) = 16, and b is set to 16. The shutter speed 602 at this time is calculated as 1 / preset frequency (for example, 3840 [Hz]) × b, which is 1 / 240 [s].

[0112] 11 is an explanatory diagram showing Example 1 of a flicker reduction frequency setting shutter time list according to Example 2. Fig. 11 shows an example in which the step number change is in 1 / 2 step steps. The flicker reduction frequency setting shutter time list 1100 is set in the imaging device 100 in place of the flicker reduction frequency setting shutter time list 600.

[0113] The flicker reduction frequency setting shutter time list 1100 has a half-step step 1001, an integer multiple of one period 601, and a shutter time 602. For the flicker reduction frequency setting shutter time list 1100, the integer multiple of one period 601 and the shutter time 602 are set in the same manner as in FIG.

[0114] 10 and 11 , the shutter speed 602 may be set in advance in the flicker reduction frequency setting shutter speed list 1000, or may be calculated each time a preset frequency is input to the image capture device 100. Even if it is calculated each time, when the ⅓ stop step 1001 and the ½ stop step 1101 are 3 or less, the step number changes roughly, so it is preferable to use all integers b=1 to 8 for the integer multiple 601 of one period, and a lookup table showing the integers b=1, 2, ..., 8 for the integer multiple 601 of one period and the corresponding step numbers 0.000, 1.000, 1.585 ..., 3 may be stored in the storage device 102.

[0115] In the flicker reduction frequency setting shutter time lists 1000 and 1100, the case where the preset frequency is 3840 [Hz] has been described as an example, but preset frequencies of 7680 [Hz], 2880 [Hz], and 1920 [Hz] may also be set, as in Example 1. Also, for the flicker reduction frequency setting shutter time lists 1000 and 1100, the method of determining the shutter time 602 in 1 / 3 step and 1 / 2 step steps has been described, but the shutter time may be determined in a similar manner for other step steps, such as 1 / 4 step, 1 / 5 step, and so on.

[0116] Thus, according to Examples 1 and 2, the number of shutter times 602 is less than either the normal shutter time list 400 or the flicker reduction shutter time list 500, and all shutter times 602 are integer multiples 601 of one period, so the user can obtain an image 202 in which the occurrence of stripes 203 is suppressed regardless of which shutter time 602 is selected.

[0117] Therefore, from a group of shutter times that contain a mixture of shutter times that cause stripes 203 to appear and shutter times that suppress the appearance of stripes 203, such as the normal shutter time list 400 and the flicker reduction shutter time list 500, it is possible to easily select the shutter time 602 that suppresses the appearance of stripes 203, without having to go through the trouble of searching for a shutter time that suppresses the appearance of stripes 203 while operating the shutter.

[0118] In this way, regardless of which shutter time 602 the user selects, an image 202 can be obtained in which the occurrence of stripes 203 is suppressed, and therefore, for example, when the user wants to change the shutter time 602 to take a picture, the situation in which a good photo opportunity is missed is reduced.

[0119] As described above, according to this embodiment, it is possible to easily suppress the occurrence of stripes in an image.

[0120] The flicker reduction mode may be set in a user-selectable shooting mode in which the shutter time 602 can be set. User-selectable shooting modes include, for example, a manual shooting mode and a shutter speed priority shooting mode. The manual shooting mode is a shooting mode in which the user can set the shutter time 602 and the aperture value. The shutter speed priority shooting mode is a shooting mode in which the user can set the shutter time 602 and the aperture value is determined by the imaging device 100, prioritizing the shutter time 602.

[0121] Furthermore, without being limited to this, the shutter speed 602 may also be set in a shooting mode determined by the imaging device 100. In this case, the imaging device 100 automatically selects the optimal shutter speed 602 from among the shutter speeds 602 that can reduce flicker.

[0122] Furthermore, the imaging apparatus 100 may be configured not only through the operation device 108 included in the imaging apparatus 100 but also through remote operation from an external smartphone, tablet, or personal computer.

[0123] The imaging device 100 can also be used to expose the image sensor 105 using a global shutter. Unlike the rolling shutter method, the global shutter method does not produce stripes for each pixel line, but when multiple images are captured in succession, the brightness of the entire image changes for each image in the series due to the first frequency of the light source 200. This makes it possible to reduce the effect of brightness changing for each image in the global shutter method.

[0124] In Example 3, an explanation will be given of automatic setting of the shutter time 602, which is an integer multiple of the period corresponding to the frequency of the light source 200, in exposure control in a specific shooting mode and automatic control of sensitivity at the low speed limit setting in Examples 1 and 2. Note that in Example 3, the explanation will focus on the differences from Examples 1 and 2, so that the same reference numerals will be used to designate parts common to Examples 1 and 2, and explanations thereof will be omitted.

[0125] 12 is a block diagram showing an example of a functional configuration of the imaging device 100 according to the third embodiment. The imaging device 100 includes a control unit 1200. The control unit 1200 executes exposure control according to the shooting mode and the low-speed limit setting. Specifically, the control unit 1200 is realized by, for example, causing the processor 101 to execute a program stored in the storage device 102 shown in FIG. 1 or by the LSI 107.

[0126] (Photographing Modes) The imaging device 100 is provided with a plurality of imaging modes: P mode, S mode, A mode, M mode, and AUTO mode. P mode is called programmed auto, and is a mode in which the imaging device 100 automatically determines the aperture value and shutter speed to achieve proper exposure. S mode is called shutter-priority auto, and is a mode in which the imaging device 100 automatically determines the aperture value that will achieve proper exposure for the shutter speed selected by the photographer. A mode is called aperture-priority auto, and is a mode in which the imaging device 100 automatically determines the shutter speed that will achieve proper exposure for the aperture value selected by the photographer. Whichever mode is selected, P mode, S mode, or A mode, proper exposure is set.

[0127] M mode is called manual exposure, and is a mode in which the photographer selects both the aperture value and shutter speed. AUTO mode is a mode in which the imaging device 100 automatically selects the aperture value, shutter speed, and ISO sensitivity. In AUTO mode, for example, the imaging device 100 determines the shooting scene and selects the aperture value, shutter speed, and ISO sensitivity based on the determined scene. Furthermore, in AUTO mode, for example, the imaging device 100 may select the aperture value, shutter speed, and ISO sensitivity based on the shooting scene selected by the user.

[0128] (Slow Speed ​​Limit Setting) The imaging device 100 also has an automatic sensitivity control function. The automatic sensitivity control function automatically controls the ISO sensitivity. The shutter speed at which the automatic sensitivity control starts is called the slow speed limit. The slow speed limit is set by default and can be changed by user operation. The automatic sensitivity control function can also be turned ON / OFF by user operation.

[0129] For example, when shooting in a dark place, the image capture device 100 approaches the correct exposure by lengthening (slowing down) the shutter speed up to the lowest limit, but if the speed becomes slower than the lowest limit, the image capture device 100 controls to increase the ISO sensitivity to approach the correct exposure. Since increasing the ISO sensitivity reduces image quality, when the exposure cannot be changed by changing the aperture value or shutter speed, the image capture device 100 controls to increase the ISO sensitivity.

[0130] However, if the minimum shutter speed is set to a value that causes flickering, for example, when attempting to take a picture in a dark place, the shutter speed will slow down and reach the minimum shutter speed, at which point flickering will occur. As a result, flickering may continue to occur during shooting.

[0131] For this reason, in the third embodiment, when the P mode, the A mode, or the AUTO mode is selected as the specific shooting mode, the image capture device 100 automatically controls the ISO sensitivity and automatically determines the shutter speed to be a value that is a multiple of the preset frequency by the number of steps. Also, by setting the slowest speed limit value to a shutter speed 602 that is an integer multiple 601 of one cycle corresponding to the first frequency, it is possible to avoid automatic setting of the shutter speed that causes flicker even when the automatic sensitivity control function is operating.

[0132] <FIG. 13 Imaging Processing Procedure> FIG. 13 is a flowchart illustrating an example of an imaging processing procedure by the imaging device 100 according to the third embodiment.

[0133] (Step S1301 ) The imaging device 100 acquires the first frequency of the light source 200 via the acquisition unit 901 .

[0134] (Step S1302) The imaging device 100 uses the determination unit 903 to determine whether the first frequency and the second frequency acquired in step S1301 match. The second frequency is one of the preset frequencies PRE1 to PRE5 set in the flicker reduction frequency setting shutter time lists 600-1 to 600-5 stored in the storage unit 900. If the first frequency and the second frequency match (step S1302: Yes), the process proceeds to step S1303. If the first frequency and the second frequency do not match (step S1302: No), the process proceeds to step S1304.

[0135] (Step S1303) The imaging device 100 selects the flicker reduction frequency setting shutter time list 600 of the second frequency that matches the first frequency. For example, if the second frequency is the preset frequency PRE1, the imaging device 100 selects the flicker reduction frequency setting shutter time list 600-1. Then, the process proceeds to step S1305.

[0136] (Step S1304) The imaging apparatus 100 creates a flicker reduction frequency setting shutter time list 600-5 based on the first frequency. Specifically, for example, the imaging apparatus 100 uses the calculation unit 904 to calculate a plurality of shutter times 602 that are integer multiples 601 of one period corresponding to the first frequency. Specifically, as described in the first embodiment, for example, if the first frequency is 7630 Hz, the imaging apparatus 100 uses the calculation unit 904 to associate the period a, which is the reciprocal of the first frequency, with the value of the integer multiple 601 of one period, "1," and the value of the relative step number 603, "0.000." The value of the integer multiple 601 of one period is set to b, and the value of the relative step number 603 is calculated by log ２ Calculate using b.

[0137] The imaging device 100 also uses the calculation unit 904 to calculate the shutter speed 602 at value b of the integer multiple 601 of one period by dividing the period a by b. The imaging device 100 also uses the calculation unit 904 to determine whether to adopt 1 / 3 stop 604 and whether to adopt 1 / 2 stop 604, as described above. As a result, a flicker reduction frequency setting shutter speed list 600-5 is created and stored in the storage unit 900. Then, the process proceeds to step S1305.

[0138] (Step S1305) The image capturing apparatus 100 determines which shooting mode is set to by the control unit 2100. If the shooting mode is set to A mode, P mode, or AUTO mode (step S1305: A, P, AUTO), the process proceeds to step S1308. On the other hand, if the shooting mode is set to M mode or S mode (step S1305: M, S), the process proceeds to step S1306.

[0139] (Step S1306) The imaging apparatus 100 displays, on the display unit 902, a plurality of shutter speeds 602 in the flicker reduction frequency setting shutter speed list 600 obtained in step S1303 or step S1304 in a selectable manner.

[0140] (Step S1307) The imaging device 100 receives a selection of one of the shutter times 602 from the plurality of shutter times 602 via the selection unit 906. For example, if the flicker reduction frequency setting shutter time list 600-1 is displayed in step S1306, the imaging device 100 receives a selection of one of the shutter times 602 in the flicker reduction frequency setting shutter time list 600-1 via the selection unit 906 using the main command dial, as shown in FIG. 7. Then, the process proceeds to step S1313.

[0141] (Step S1308) The image capturing apparatus 100 acquires exposure control values ​​Tv1, Av1, and Sv1 according to the shooting mode via the control unit 2100. The exposure control value Tv# (# is a number) is the shutter speed. The exposure control value Av# is the aperture value. The exposure control value Sv# is the sensitivity. The image capturing apparatus 100 acquires the brightness value Bv of the subject by measuring the photometry of the subject.

[0142] The image capturing apparatus 100 calculates an exposure control value Tv1 according to the shooting mode using the following equation (1).

[0143] Bv#=Tv#+Av#-Sv#...(1)

[0144] When the shooting mode is A mode, the image capturing apparatus 100 accepts Av1 and Sv1 through user operation. In this case, the exposure control value Tv1 is calculated by the following formula (2), which is a modification of the above formula (1).

[0145] Tv#=Bv#-(Av#-Sv#)...(2)

[0146] If the automatic sensitivity control function of the imaging device 100 is set to ON, and the exposure control value Tv1 calculated by the above formula (2) is lower than a predetermined value, the exposure control value Tv1 is changed to the predetermined value. This predetermined value is the slowest limit value, i.e., the limit value beyond which the shutter speed cannot be increased (decreased). Then, when the exposure control value Tv1 is changed to the predetermined value, the imaging device 100 changes the exposure control value Sv1 so that the above condition (2) is satisfied.

[0147] Furthermore, when the shooting mode is P mode, the image capturing apparatus 100 accepts Sv1 through a user operation. The image capturing apparatus 100 determines the exposure control value Tv1 and the exposure control value Av1 corresponding to the exposure control value Sv1 input through operation in accordance with the program diagram in the storage device 102.

[0148] If the automatic sensitivity control function of the image capture device 100 is set to ON, and the exposure control value Tv1 determined according to the program diagram is lower than the slowest speed limit, the image capture device 100 changes the exposure control value Tv1 to the slowest speed limit. Then, when the exposure control value Tv1 is changed to the slowest speed limit, the image capture device 100 changes the exposure control value Sv1 so as to satisfy the above condition (2).

[0149] (Step S1309) The image capturing apparatus 100, via the control unit 1200, selects the shutter time 602 closest to the exposure control value Tv1 from the flicker reduction frequency setting shutter time list 600 as the exposure control value Tv2. Note that the shutter time 602 closest to the exposure control value Tv1 is just an example, and any shutter time 602 that is second or subsequent closest to the exposure control value Tv1 may be selected as long as it is within the allowable range of the exposure control value Tv1, or may be the shutter time 602 closest on the longer side (slower side) than the slowest limit value (the same applies below). The same applies to the shutter time 602 closest to the slowest limit value.

[0150] Furthermore, if the exposure control value Sv1 calculated in step S1308 is a lower limit value that cannot be lowered any further (for example, Sv1 = ISO 100), the imaging device 100 may select, as the exposure control value Tv1, the shutter speed 602 that is closest to the exposure control value Tv1 calculated in step S1308 from among the shutter speeds 602 that are shorter (faster) than the exposure control value Tv1.

[0151] Furthermore, in step S1309, the imaging apparatus 100 may accept a user's operation to set a minimum shutter speed limit in advance from the input unit 905. This user-set minimum shutter speed limit is a shutter speed at which it is possible for flicker to occur.

[0152] When the exposure control value Tv1 is slower (on the slower side) than the user-set slowest limit, the image capture device 100 does not change the exposure control value Tv1 to the user-set slowest limit, but instead changes the exposure control value Tv1 to the shutter speed 602 that is shorter (faster) than the user-set slowest limit and that is closest to the user-set slowest limit. This allows the user to set the slowest limit with a conventional feel. Furthermore, even if the user-set slowest limit is a shutter speed that causes flickering, the image capture device 100 can automatically set it to a shutter speed 602 that does not cause flickering.

[0153] Furthermore, when the user sets the low speed limit value, the imaging device 100 may display a flicker reduction frequency setting shutter speed list 600 on the display unit 902, and allow the user to select a shutter speed 602 from the flicker reduction frequency setting shutter speed list 600 to set the low speed limit value.

[0154] Furthermore, the imaging device 100 may automatically set the slowest speed limit. Specifically, for example, the imaging device 100 sets the slowest speed limit to a predetermined value. This predetermined value may be, for example, 1 / focal length. Specifically, for example, the imaging device 100 may set the shutter speed 602 to a value close to 1 / focal length, at which no flicker occurs.

[0155] Thereafter, when the exposure control value Tv1 obtained in step S1308 becomes slower than the lowest speed limit (becomes the low speed side), the image capture device 100 changes the exposure control value Tv1 to the lowest speed limit. The image capture device 100 then sets the lowest speed limit, changed from the exposure control value Tv1, as the exposure control value Tv2 and executes steps S1310 to S1312. In this way, an appropriate lowest speed limit can be automatically set regardless of the user's level of proficiency, improving convenience.

[0156] (Step S1310) The image capturing apparatus 100 calculates the exposure time difference dTv using the control unit 1200. The exposure time difference dTv is calculated using the following formula (3).

[0157] dTv=Tv1-Tv2...(3)

[0158] (Step S1311) The image capturing apparatus 100 calculates an exposure control value Sv2 using the control unit 1200 according to the following equation (4).

[0159] Sv2=Sv1-dTv...(4)

[0160] The image capturing apparatus 100 may use the control unit 1200 to calculate the exposure control value Av2 according to the following equation (5).

[0161] Av2=Av1-dTv...(5)

[0162] (Step S1312) The image capturing apparatus 100 controls exposure using the control unit 1200 based on the exposure control value Tv2, the exposure control value Av1 (or the exposure control value Av2), and the exposure control value Sv2.

[0163] (Step S1313) The imaging device 100 captures an image of the subject using the imaging unit 120. Specifically, for example, the imaging device 100 generates and displays a live view image of the subject, or captures an image of the subject when the release button is pressed. This completes the series of processes.

[0164] In this way, according to the process shown in FIG. 13, when capturing an image in a specific shooting mode, the imaging device 100 can automatically control exposure while automatically setting the shutter time 602 to an integer multiple of the period corresponding to the frequency of the light source 200.

[0165] The present invention is not limited to the above-described contents, and may be implemented by any combination thereof. Furthermore, other embodiments conceivable within the scope of the technical concept of the present invention are also included in the scope of the present invention.

[0166] 100 Imaging device, 101 Processor, 102 Storage device, 111 Display device, 200 Light source, 201, 202 Image, 203 Stripe, 400 Normal shutter speed list, 402 Shutter speed, 500 Flicker reduction shutter speed list, 502 Shutter speed, 600 Flicker reduction frequency setting shutter speed list, 601 Integer multiple of one period, 602 Shutter speed, 603 Number of steps, 604 Adoption / non-adoption of 1 / 3 step, 605 Adoption / non-adoption of 1 / 2 step, 900 Storage unit, 901 Acquisition unit, 902 Display unit, 903 Determination unit, 904 Calculation unit, 905 Input unit, 906 Selection unit, 907 Image processing unit

Claims

1. An imaging device having: an acquisition unit that acquires a first frequency of a light source; and a display unit that selectably displays a plurality of shutter speeds that are integer multiples of a period corresponding to the first frequency acquired by the acquisition unit.

2. An imaging device according to claim 1, wherein the acquisition unit accepts selection of one of a plurality of first frequencies.

3. An imaging device according to claim 1, wherein the acquisition unit accepts input of the first frequency.

4. An imaging device according to claim 1, wherein the acquisition unit detects the first frequency based on a blinking cycle of the light source.

5. An imaging device according to any one of claims 1 to 4, comprising: a storage unit that stores a plurality of shutter speeds that are integer multiples of a period corresponding to the second frequency of the light source; and a determination unit that determines whether the first frequency and the second frequency match; and the display unit that selectably displays the plurality of shutter speeds based on the determination result by the determination unit.

6. An imaging device according to claim 5, wherein the display unit, when it is determined that the first frequency and the second frequency match, displays the plurality of shutter speeds stored in the memory unit in a selectable manner.

7. An imaging device according to claim 5, further comprising a calculation unit that, when it is determined that the first frequency and the second frequency do not match, calculates multiple shutter speeds that are integer multiples of the period corresponding to the first frequency, and the display unit selectably displays the multiple shutter speeds calculated by the calculation unit.

8. An imaging device according to claim 5, further comprising an input unit that receives an input for changing the first frequency, and the determination unit determines whether the first frequency after change by the input unit matches the second frequency.

9. An imaging device according to any one of claims 1 to 8, wherein the display unit, for a first shutter speed group among the plurality of shutter speeds that is equal to or shorter than a predetermined shutter speed, displays all first shutter speeds within the first shutter speed group in a selectable manner.

10. An imaging device according to any one of claims 1 to 9, wherein the display unit selectably displays, from among the plurality of shutter speeds, a plurality of second shutter speeds that are not consecutive integer multiples of the period.

11. An imaging device according to any one of claims 1 to 10, wherein the display unit, for a second shutter time group that is greater than a predetermined shutter time among the plurality of shutter times, selectably displays a plurality of second shutter times that are not consecutive integer multiples of the period in the second shutter time group.

12. An imaging device according to claim 9, wherein the display unit selectably displays, from among the plurality of shutter speeds, the shutter speed that minimizes the difference between the amount of change in the number of steps when the shutter speed based on the first frequency of the light source is used as a reference and a constant multiple of a predetermined number of steps.

13. An imaging device according to claim 11, wherein the display unit selectably displays the second shutter speed from the second shutter speed group that minimizes the difference between the amount of change in the number of steps when the shutter speed based on the first frequency of the light source is used as the reference and a constant multiple of a predetermined number of steps.

14. An imaging device according to claim 12 or 13, wherein the predetermined number of stages includes at least 1 stage, 1 / 3 stage, or 1 / 2 stage.

15. An imaging device according to any one of claims 1 to 14, comprising: a selection unit that accepts selection of one of the plurality of shutter speeds; and an imaging unit that images a subject based on the shutter speed selected by the selection unit.

16. An imaging device having: an acquisition unit that acquires a first frequency of a light source; and an imaging unit that images a subject based on a plurality of shutter speeds that are integer multiples of a period corresponding to the first frequency acquired by the acquisition unit.

17. An imaging device according to claim 16, wherein the acquisition unit accepts selection of one of a plurality of first frequencies.

18. An imaging device according to claim 17, wherein the acquisition unit accepts input of the first frequency.

19. An imaging device according to claim 17, wherein the acquisition unit detects the first frequency based on flicker of the light source.

20. An imaging device having: a memory unit that stores multiple shutter speeds that are integer multiples of a period corresponding to the frequency of a light source; and a control unit that selects a second shutter speed from among the multiple shutter speeds based on a first shutter speed obtained according to a shooting mode, and controls exposure based on the second shutter speed.

21. An imaging device according to claim 20, wherein the control unit, when the first shutter time becomes slower than a predetermined shutter time, changes the first shutter time to the predetermined shutter time, selects the second shutter time from among the plurality of shutter times based on the changed first shutter time, and controls exposure based on the second shutter time.

22. A program that causes a processor to execute an acquisition process for acquiring a first frequency of a light source, and a display process for selectively displaying a plurality of shutter speeds that are integer multiples of the period corresponding to the first frequency acquired by the acquisition process.

23. A program that causes a processor to execute the following steps: a process of selecting a second shutter speed from among a plurality of shutter speeds that are integer multiples of the period corresponding to the frequency of the light source, based on a first shutter speed obtained according to the shooting mode; and a control process of controlling exposure based on the second shutter speed.

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