Image capturing apparatus, method of controlling the same, and storage medium

Abstract

To provide an imaging apparatus capable of notifying a user of a photographing method in which flickerless photographing is effective, a method of controlling the same, and a program.SOLUTION: A digital camera 100 detects light source information of a light source at the time of imaging from an image signal obtained by imaging an object by an imaging element 103, and when the light source at the time of imaging is a flicker light source, selects a reduction processing means effective for reducing the influence of the flicker light source from three reduction processing means on the basis of the detected light source information, and notifies a user of the selected reduction processing means.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an imaging device, a control method thereof, and a program, and more particularly to an imaging device that performs flicker-free imaging, a control method thereof, and a program. [Background technology]

[0002] When capturing still images or videos under a flickering light source, the effects of the flicker can appear in the image as uneven brightness or stripes. Several methods for capturing images that reduce the effects of flicker (hereinafter referred to as flicker-less capture) have been known. Patent Document 1 proposes a capture method that detects flicker and captures images at a timing that minimizes the effects of the detected flicker. Patent Document 2 proposes a capture method that sets the accumulation time to an integer multiple of the flicker cycle, and Patent Document 3 proposes a capture method that detects and corrects line flicker caused by a slit rolling shutter during capture. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-58844 A [Patent Document 2] Japanese Patent Publication No. 2022-129925 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-17213 Summary of the Invention [Problem to be solved by the invention]

[0004] However, while the shooting method described in Patent Document 1 can capture images with reduced flicker effects, it also creates a release time lag that corresponds to the timing of the shot. For this reason, the camera must use an icon or other means to notify the user that the camera is in a flicker environment and that flicker-free shooting will be performed, requiring the user to understand that limited functionality will be present before shooting.

[0005] The imaging methods described in Patent Documents 2 and 3 also have limited functionality. For example, in the former case, it is necessary to set an accumulation time that is an integral multiple of the flicker cycle, while in the latter case, the image is affected by noise due to image correction gain.

[0006] Therefore, it is desirable to select a shooting method that is effective for anti-flicker shooting depending on the shooting environment and scene, but it is difficult to get the user to make such an appropriate selection.

[0007] The present invention provides an imaging device that can notify a user of an imaging method in which flicker-free imaging is effective, a control method for the imaging device, and a program. [Means for solving the problem]

[0008] In order to solve the above problem, the imaging device according to claim 1 of the present invention is characterized by comprising: an imaging means for imaging a subject to obtain an image signal; a detection means for detecting light source information of the light source at the time of imaging from the image signal; a selection means for selecting, if the light source at the time of imaging is a flicker light source, a reduction processing means that is effective in reducing the influence of the flicker light source from among a plurality of flicker reduction processing means based on the detected light source information; and a notification means for notifying a user of the selected reduction processing means. [Effects of the Invention]

[0009] According to the present invention, it is possible to notify the user of a shooting method in which flicker-free shooting is effective. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram showing the hardware configuration of a digital camera as an imaging apparatus according to the present invention. [Figure 2A] FIG. 10 is an image diagram illustrating a flicker reduction processing means based on the shooting timing. [Figure 2B] FIG. 10 is an image diagram illustrating a flicker reduction processing means based on accumulation time. [Figure 2C] FIG. 10 is an image diagram illustrating a flicker reduction processing means using an image correction gain. [Figure 3] 1 is a flowchart showing the flow of the entire process according to the first embodiment of the present invention. [Figure 4A] 4 is a flowchart of a process for determining the effectiveness of a flicker reduction processing means based on the shooting timing in step S103 of FIG. 3. [Figure 4B] 4 is a flowchart of the process of determining the effectiveness of the flicker reduction processing means based on the accumulation time in step S104 of FIG. 3. [Figure 4C] 4 is a flowchart of the process of determining the effectiveness of the flicker reduction processing means based on the image correction gain in step S105 of FIG. 3. [Figure 5A] 4 is a flowchart of a notification control process in step S106 of FIG. 3 according to the first embodiment of the present invention. [Figure 5B] 5B is a flowchart of a priority determination process for the reduction method in step S304 of FIG. 5A. [Figure 6] FIG. 5B is an image diagram showing an example of icon display by the flicker notification unit in step S303 of FIG. 5A. [Figure 7] 10 is a flowchart of a notification control process in step S106 of FIG. 3 according to the second embodiment of the present invention. [Figure 8] FIG. 8 is an image diagram showing an example of icon display by the flicker notification unit in step S406 of FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0012] A digital camera 100 (hereinafter simply referred to as camera 100) as an imaging device according to an embodiment of the present invention will be described below with reference to FIG.

[0013] FIG. 1 is a block diagram showing the hardware configuration of the camera 100. As shown in FIG.

[0014] 1, camera 100 includes a lens group 101, a lens control unit 102, an image sensor 103, a signal processing unit 104, a recording processing unit 105, a recording medium 106, a camera control unit 107, an operation unit 108, a shooting timing calculation unit 109, and an accumulation time calculation unit 110. Camera 100 also includes a flicker correction calculation unit 111, an exposure control unit 112, a flicker detection unit 113, a flicker reduction processing determination unit 114, a flicker notification unit 115, a motion detection unit 116, and a display unit 117.

[0015] The lens group 101 includes a mechanism for controlling exposure by an aperture and a mechanism for controlling focus and zoom operations, and focuses incident light onto an image sensor 103 (image pickup means) to form an optical image.

[0016] The image sensor 103 converts the formed optical image into an electrical signal and outputs it to the signal processor 104. At this time, the lens group 101 drives the aperture to control the accumulation time in the image sensor 103 and the amplification factor of the electrical signal, thereby controlling the exposure of the captured image.

[0017] The signal processing unit 104 performs gain correction such as luminance correction and flicker correction, color correction such as white balance, and other signal processing on the image signal obtained from the image sensor 103, and outputs the image signal to the recording processing unit 105 and the display unit 117. Note that flicker correction is a means of applying correction based on light source information of the flicker light source detected by the flicker detection unit 113, and details of this will be described later.

[0018] The display unit 117 includes a liquid crystal screen provided on the rear surface of the main body of the camera 100, and displays icons shown in FIG. 6, which will be described later, and displays the image signal output from the signal processing unit 104 as an image.

[0019] The recording processing unit 105 converts the image signal output from the signal processing unit 104 into an image signal in a format recordable by the recording medium 106, outputs the image signal to the recording medium 106, and causes the image signal to be recorded on the recording medium of the recording medium 106.

[0020] The camera control unit 107 incorporates a CPU, ROM, and RAM (not shown in FIG. 1), and the CPU loads programs stored in the ROM into the RAM and executes them, thereby controlling the entire camera 100. The camera control unit 107 functions as a controller that controls the flow of a series of image processes executed by the camera 100, and the other blocks shown in FIG. 1 are connected to the camera control unit 107. The camera control unit 107 accepts operations from the user via the operation unit 108 and calculates settings related to zoom, focus, and brightness of the captured image according to the selected shooting mode and the brightness of the subject. The camera control unit 107 also transmits the calculated settings to the lens control unit 102 and exposure control unit 112, and controls each component to a control position and state according to the setting values.

[0021] The flicker detection unit 113 (detection means) receives as input the electrical signal of the optical image (captured image) accumulated by the image sensor 103, and detects light source information such as the frequency, phase, and waveform of the brightness change if the light source at the time of capture was a flicker light source based on the periodicity of the brightness change between the previous and next images.

[0022] The photographing timing calculation unit 109 (timing calculation means) determines the timing to perform photographing from the frequency and phase of the flicker detected by the flicker detection unit 113, and notifies the camera control unit 107. The camera control unit 107 performs photographing based on the timing notified from the photographing timing calculation unit 109.

[0023] The accumulation time calculation unit 110 (accumulation time calculation means) calculates an accumulation time that is N times the frequency of the flicker detected by the flicker detection unit 113, and notifies the camera control unit 107. The camera control unit 107 transmits the accumulation time notified from the accumulation time calculation unit 110 to the exposure control unit 112, and executes shooting.

[0024] The flicker correction calculation unit 111 (correction calculation means) calculates the amount of correction for the in-plane luminance unevenness due to flicker detected by the flicker detection unit 113, and notifies the signal processing unit 104. Based on the calculation result by the flicker correction calculation unit 111, the signal processing unit 104 performs gain correction on the captured image so as to reduce the exposure unevenness due to flicker.

[0025] When flicker is detected by flicker detection unit 113, flicker reduction processing determination unit 114 (selection means) selects at least one flicker reduction processing means, which will be described later, based on information about the detected flicker and the shooting conditions set by operation unit 108. The selected flicker reduction processing means is notified by flicker notification unit 115 (notification means). For example, flicker notification unit 115 notifies the selected flicker reduction processing means by displaying an icon on display unit 117 in FIG. 6, which will be described later.

[0026] The shooting timing calculation unit 109, accumulation time calculation unit 110, flicker correction calculation unit 111, exposure control unit 112, flicker detection unit 113, and flicker reduction processing determination unit 114 may be included in the camera control unit 107.

[0027] The motion detection unit 116 includes a sensor such as a gyro sensor (not shown), and based on the output results of the sensor, detects the attitude and motion (angle, acceleration, amount of movement, etc.) of the camera 100 body. The motion detection unit 116 may also detect a movement vector of a feature point in a captured image as the motion of the camera 100 body.

[0028] <About flicker reduction processing means> Hereinafter, three flicker reduction processing means according to the present invention for reducing the influence of a flickering light source when performing flickerless photography will be described with reference to FIGS. 2A to 2C.

[0029] FIG. 2A is an image diagram illustrating a flicker reduction processing means based on the shooting timing.

[0030] The flicker reduction processing means shown in FIG. 2A detects the frequency and phase of the flickering light source that is occurring, and sets the shooting timing to a timing that is less susceptible to the effects of flicker.

[0031] Specifically, image capture is controlled so that the timing at which the shutter moves from the top to the bottom of the image sensor 103 coincides with the timing at which the flickering light source is brightest. This makes it possible to capture an image in which the center of the screen is brightest and the brightness gradually decreases from the center to the top and bottom of the screen.

[0032] FIG. 2B is an image diagram illustrating a flicker reduction processing means based on accumulation time.

[0033] The flicker reduction processing means shown in FIG. 2B adjusts the accumulation time to the flickering light source that is occurring, thereby capturing an image without being affected by flicker.

[0034] By capturing an image with an accumulation time that is an integral multiple of one cycle time (flicker cycle) of the flickering light source, all pixels from the top to the bottom of the image sensor 103 can be accumulated with the same exposure amount, reducing the effects of flicker.

[0035] FIG. 2C is an image diagram illustrating a flicker reduction processing means using an image correction gain.

[0036] The flicker reduction processing means shown in FIG. 2C extracts the components of the flickering light source and applies a correction gain after shooting, thereby reducing the effects of flicker.

[0037] For example, the flicker component can be extracted by comparing an image generated by applying a recursive low-pass filter with an image in which flicker appears, and the flicker correction gain value can be calculated by taking the reciprocal of the extracted flicker component. By setting this correction value in the signal processing unit 104, an image in which the effects of correction are reduced can be generated.

[0038] The shutter method is not particularly limited and may be a slit rolling shutter as in this embodiment or a global shutter. However, a slit rolling shutter is limited to low-frequency flicker frequencies equal to or lower than the curtain speed, while a global shutter does not have any limit on the range of supported frequencies. Therefore, with a slit rolling shutter, the flicker reduction processing means shown in FIG. 2A cannot be effectively used depending on the flicker frequency. Furthermore, if the flicker source has a unique waveform other than the parabolic waveform shown in FIG. 2A, the slit rolling shutter cannot handle it, whereas a global shutter can. Therefore, with a slit rolling shutter, the flicker reduction processing means shown in FIG. 2A cannot be used depending on the waveform of the flicker source. Furthermore, with the flicker reduction processing means shown in FIG. 2B, as described above, the accumulation time must be an integer multiple of the flicker period. On the other hand, a global shutter does not have any limit on the accumulation time, but requires increased gain to suppress uneven shutter release.

[0039] Example 1 The overall flow of this embodiment will be described below using the flowchart in Fig. 3. Also, the effectiveness determination process for each of the flicker reduction processing means shown in Fig. 2A to Fig. 2C will be described using the flowcharts in Fig. 4A to Fig. 4C. Also, the notification control process in step S106 in Fig. 3 will be described using the flowcharts in Fig. 5A and Fig. 5B, and a display example based on the notification control process will be described in Fig. 6.

[0040] 3 is a flowchart showing the overall processing flow of this embodiment. Specifically, this processing is executed by a CPU built into the camera control unit 107 loading a program stored in a ROM into a RAM, but hereinafter, the entity that executes this processing will simply be the camera control unit 107.

[0041] In step S101, the flicker detection unit 113 detects any flicker that has occurred, and the process proceeds to step S102.

[0042] In step S102, it is determined whether or not flicker has been detected. If the determination result shows that flicker has not been detected (NO in step S102), the process proceeds to notification control in step S106. On the other hand, if flicker has been detected (YES in step S102), the flicker reduction process determination unit 114 (selection means) determines the effectiveness of each flicker reduction process means based on at least one piece of information of frequency, phase, and waveform in steps S103 to S105.

[0043] In step S103, the effectiveness of the flicker reduction processing means is determined based on the shooting timing. In step S104, the effectiveness of the flicker reduction processing means is determined based on the accumulation time. In step S105, the effectiveness of the flicker reduction processing means is determined based on the image correction gain. After the determinations in steps S103 to S105 are completed, the process proceeds to step S106, where notification control processing is performed based on the determination results, and the flicker notification unit 115 notifies the user of the effective flicker reduction processing means.

[0044] Then, in step S107, it is determined whether or not an effective flicker reduction processing means is present. If the determination result shows that an effective flicker reduction processing means is present (YES in step S107), the process proceeds to step S108, where flickerless shooting is performed, and then this process ends. On the other hand, if an effective flicker reduction processing means is not present (NO in step S107), the process proceeds to step S109, where normal shooting is performed, and then this process ends.

[0045] FIG. 4A is a flowchart of the process of determining the effectiveness of the flicker reduction processing means based on the shooting timing in step S103 of FIG.

[0046] First, in step S201, it is determined whether or not a still image is being captured. If it is a still image (YES in step S201), the capture timing can be freely controlled, so the process proceeds to step S202. On the other hand, if it is a moving image (NO in step S201), the process proceeds to step S206, where it is determined that the flicker reduction processing means based on the capture timing is not effective, and the process ends.

[0047] In step S202, it is determined whether or not the flicker frequency has been detected by the flicker detection unit 113. If the flicker frequency has been detected (YES in step S202), the process proceeds to step S203. On the other hand, if the flicker frequency cannot be detected (NO in step S202), the shooting timing cannot be adjusted, so the process proceeds to step S206, where it is determined that the flicker reduction processing means based on the shooting timing is not effective, and this process ends.

[0048] In step S203, it is determined whether or not the flicker phase has been detected by the flicker detection unit 113. If the flicker phase cannot be detected (NO in step S203), the shooting timing cannot be synchronized, so the process proceeds to step S206, where it is determined that the flicker reduction processing means based on the shooting timing is ineffective, and this process ends. On the other hand, if the flicker phase has been detected (YES in step S203), the process proceeds to step S204.

[0049] In step S204, it is determined whether the detected frequency is equal to or less than a threshold value. This threshold value may be, for example, the time it takes for each pixel from the top to the bottom of the image sensor 103 to start accumulation (hereinafter referred to as the curtain speed). If "one cycle time of flicker ≦ curtain speed," even if the center of gravity of image accumulation is aligned with the brightest timing of the flicker light source, brightness unevenness and stripes will occur due to the influence of flicker. If the detected frequency is equal to or less than the threshold value (YES in step S204), the process proceeds to step S205, where it is determined that the flicker reduction processing means based on the shooting timing is effective, and this process ends. If the detected frequency is greater than the threshold value (NO in step S204), the process proceeds to step S206, where it is determined that the flicker reduction processing means based on the shooting timing is not effective, and this process ends.

[0050] FIG. 4B is a flowchart of the process of determining the effectiveness of the flicker reduction processing means based on the accumulation time (Tv) in step S104 of FIG.

[0051] First, step S211 is omitted because it is the same as step S202 in Fig. 3. If the flicker frequency can be detected (YES in step S211), the process proceeds to step S212. On the other hand, if the flicker frequency cannot be detected (NO in step S211), the process proceeds to step S215, where it is determined that the flicker reduction processing means based on accumulation time is not effective, and the process ends.

[0052] Step S212 determines whether the mode is one in which Tv is determined by the camera 100, i.e., by the camera control unit 107, or one in which Tv is set by the user. If the mode is one in which Tv is determined by the camera 100 (YES in step S212), the process proceeds to step S214, where it is determined that the flicker reduction processing means based on accumulation time is enabled, and the process ends. This is because in this case, Tv is set by the camera control unit 107 to an integer multiple of the reciprocal of the detected flicker frequency (flicker period). On the other hand, if the mode is one in which Tv is set by the user (NO in step S212), the process proceeds to step S213.

[0053] In step S213, it is determined whether Tv set by the user is an integer multiple of the detected flicker period. If it is an integer multiple (YES in step S213), the process proceeds to step S214, where it is determined that the flicker reduction processing means based on accumulation time is effective, and this process ends. On the other hand, if it is not an integer multiple (NO in step S213), the process proceeds to step S215, where it is determined that the flicker reduction processing means based on accumulation time is not effective, and this process ends.

[0054] If it is determined in step S212 that the mode is one in which the user sets Tv, the flicker reduction function may be prioritized and the mode may be changed to one in which Tv is determined by the camera control unit 107. In this case, after the mode change, the process proceeds to step S214.

[0055] FIG. 4C is a flowchart of the process of determining the effectiveness of the flicker reduction processing means using the image correction gain in step S105 of FIG.

[0056] First, step S221 is omitted because it is the same as step S202 in Fig. 3. If the flicker frequency can be detected (YES in step S221), the process proceeds to step S222. On the other hand, if the flicker frequency cannot be detected (NO in step S221), the process proceeds to step S224, where it is determined that the flicker reduction processing means using the image correction gain is not effective, and the process ends.

[0057] Step S222 determines whether the condition that the capture period of the correction gain calculation image is an integer multiple of the reciprocal of the detected flicker frequency (flicker period) is met. For example, if the flicker frequency is 120 Hz and the correction gain calculation image is a live view image captured at a 30 fps capture period, the flicker period will be an integer multiple of the capture period of the correction gain calculation image. In this case, even if stripes or brightness unevenness due to flicker occur, they will remain in the same position on the screen. As a result, an image free from flicker cannot be generated by applying a recursive low-pass filter, and the correction value cannot be calculated correctly. Therefore, if the above-mentioned condition is not met (NO in step S222), correction value calculation is possible, so the process proceeds to step S223, where it is determined that the flicker reduction processing means using the image correction gain is effective, and this process ends. On the other hand, if the above-mentioned condition is met (YES in step S222), correction value calculation is not possible, so the process proceeds to step S224, where it is determined that the flicker reduction processing means using the image correction gain is ineffective, and this process ends.

[0058] Next, the notification control process in step S106 of FIG. 3 and an example of notification display by this process will be described with reference to FIGS. 5A, 5B, and 6. FIG.

[0059] FIG. 5A is a flowchart of the notification control process in step S106 of FIG. 3 according to this embodiment.

[0060] First, in step S301, it is determined whether or not flicker was detected in step S102 of Fig. 3. If flicker was not detected (NO in step S301), the process proceeds to step S306, where all three icons shown in Fig. 6 corresponding to the flicker reduction processing means are turned off. On the other hand, if flicker was detected (YES in step S301), the process proceeds to step S302, where it is determined whether or not a setting that allows the user to select the reduction method is enabled.

[0061] If the setting for the user to select the reduction method is enabled (YES in step S302), proceed to step S303. On the other hand, if the setting for the user to select the reduction method is not enabled (NO in step S302), proceed to step S302a.

[0062] In step S303, of the three icons shown in Figure 6, all icons corresponding to flicker reduction means determined to be effective in the processing of Figures 4A to 4C are illuminated as icons corresponding to usable reduction methods (first notification control method).

[0063] In step S302a, it is determined whether or not the setting for automatically selecting the reduction method in the camera 100 (camera control unit 107) is enabled.

[0064] If the setting for automatically selecting a reduction method in the camera 100 is enabled (YES in step S302a), the process proceeds to step S304. On the other hand, if the setting for automatically selecting a reduction method in the camera 100 is not enabled (NO in step S302a), the process proceeds to step S109, and normal shooting is performed.

[0065] In step S304, a process for determining the reduction method with the highest priority (reduction method priority determination process) is executed (determination means). This process will be described with reference to FIG. 5B. Thereafter, the process proceeds to step S305, and of the three icons shown in FIG. 6, the icon corresponding to the reduction method with the highest priority determined in the process of step S304 is turned on (second notification control method). At this time, for example, if the "gain" icon is turned on, the gain amount at that time is set on the camera 100 side (camera control unit 107). Similarly, if the "timing" or "accum" icon is turned on, the camera 100 side (camera control unit 107) sets the appropriate timing and accumulation time.

[0066] Fig. 5B is a flowchart of the reduction method priority determination process in step S304 of Fig. 5A. Here, the reduction method with the highest priority means the reduction method that is most effective in reducing the effects of flicker.

[0067] First, in step S311, it is determined whether the mode is one in which the user sets Tv or one in which Tv is determined by the camera 100 (accumulation time calculation unit 110). If the mode is the former (YES in step S311), unlike the latter mode, the camera 100 (accumulation time calculation unit 110) cannot adjust the accumulation time to the detection frequency. Therefore, the process proceeds to step S314 to determine either the shooting timing or the flicker reduction processing means using the image correction gain as the reduction method with the highest priority. On the other hand, if the mode is the latter (NO in step S311), the process proceeds to step S312.

[0068] In step S314, it is determined whether the ISO used for shooting is a high ISO equal to or greater than a certain predetermined value. If the ISO is equal to or greater than the predetermined value (YES in step S314), there is a concern about the image quality when image correction gain is applied later, so the process proceeds to step S315, where the flicker reduction processing method based on shooting timing is determined as the reduction method with the highest priority, and the process ends. On the other hand, if the ISO is less than the predetermined value (NO in step S314), there is no concern about frame rate limitations or release time lag, so the process proceeds to step S316, where the flicker reduction processing method based on image correction gain is determined as the reduction method with the highest priority, and the process then ends.

[0069] In step S312, it is determined whether the photographed subject is a moving subject. This determination is made, for example, by detecting a change in the position of the photographed subject in successive photographed images. If the photographed subject is a moving subject (YES in step S312), the process proceeds to step S313. On the other hand, if the photographed subject is not a moving subject (NO in step S312), the process proceeds to step S317, where the accumulation time-based flicker reduction processing method is determined to be the reduction method with the highest priority, and the process ends.

[0070] In step S313, since it is desirable to shoot a moving subject with a relatively short accumulation time to prevent subject blur, it is determined whether the flicker period, which is the reciprocal of the flicker frequency (= the minimum accumulation time required to eliminate flicker), is equal to or longer than a predetermined time. If it is shorter than the predetermined time (NO in step S313), the accumulation time-based flicker reduction processing means can handle shooting of moving subjects, so the process proceeds to step S317, where the accumulation time-based flicker reduction processing means is determined to be the reduction method with the highest priority, and this process ends. On the other hand, if it is equal to or longer than the predetermined time (YES in step S313), the accumulation time-based flicker reduction processing means will cause subject blur when shooting a moving subject, so the process proceeds to step S314. The rest of the process is as described above and will not be repeated here.

[0071] As described above, according to this processing, the optimum means for the image capturing environment is selected from among a plurality of flicker reduction processing means.

[0072] FIG. 6 is an image diagram showing an example of icon display by flicker notification unit 115 in step S303 of FIG. 5A.

[0073] 6, flicker notification unit 115 displays three icons labeled "accum," "timing," and "gain" vertically from top to bottom in the upper right corner of the liquid crystal screen of display unit 117. These three icons correspond to the flicker reduction processing means.

[0074] The icon marked "accum" corresponds to a flicker reduction processing means based on accumulation time, the icon marked "timing" corresponds to a flicker reduction processing means based on shooting timing, and the icon marked "gain" corresponds to a flicker reduction processing means based on image correction gain.

[0075] 6, only the icon labeled "accum" is turned off, and the icons labeled "timing" and "gain" are turned on. In other words, this is an example in which the user is notified that the flicker reduction processing means based on the accumulation time is not effective, but that the flicker reduction processing means based on the shooting timing and image correction gain are effective.

[0076] As described above, this embodiment allows the user to determine whether a flicker light source is present in the shooting environment and which flicker reduction processing means should be used to achieve the desired flicker reduction effect. For example, when shooting a moving subject in a 100 Hz flicker environment and the user sets Tv to 1 / 1000, the icon shown in FIG. 6 is displayed through the process shown in the flowcharts of FIGS. 3 to 5B. Therefore, the user can select either a flicker reduction processing means based on shooting timing or a flicker reduction processing means based on image correction gain. Therefore, the user can select the former if they do not want to apply image correction gain, or the latter if they want to prioritize the frame rate for continuous shooting. In this way, the notification content from the flicker notification unit 115 can serve as auxiliary information for the user to select a flicker reduction processing means based on their own priorities.

[0077] Although the present embodiment has been described with reference to a case in which the camera 100 has three types of flicker reduction processing means, other flicker reduction processing means may also be included. In this case, a determination process is performed according to the other flicker reduction processing means, and an icon whose on / off state is controlled by the flicker notification unit 115 according to the determination result is provided on the display unit 117. Here, an example of the other flicker reduction processing means is a means for attenuating the flickering of stripes by applying a low-pass filter when stripes appear in an image captured under a high-frequency flickering light source, where the stripes flicker every 10 pixels out of 4000 vertical pixels of the image.

[0078] Furthermore, in this embodiment, an example has been described in which the user is notified of effective flicker reduction processing means by controlling the lighting / extinguishing of icons corresponding to the respective flicker reduction processing means, but this is not limited to this as long as the notification means allows the user to distinguish effective flicker reduction processing means. For example, the color of the corresponding icon may be changed depending on whether the icon is effective as a flicker reduction processing means.

[0079] Furthermore, in this embodiment, an example has been shown in which icons representing each flicker reduction processing means are provided on the display unit 117, but instead of icons, light source information (such as frequency) of the flicker light source detected by the flicker detection unit 113 may be displayed.

[0080] Example 2 An example of the notification control process according to this embodiment and icon display by the flicker notification unit 115 will be described below with reference to FIGS.

[0081] This embodiment has the same hardware configuration as that of the first embodiment, and the processes described using the flowcharts of FIG. 3 and FIGS. 4A to 4C are common to the first embodiment, so the description thereof will be omitted.

[0082] FIG. 7 is a flowchart of the notification control process in step S106 of FIG. 3 according to this embodiment.

[0083] First, in step S401, it is determined whether or not flicker has been detected in step S102 of FIG.

[0084] If no flicker is detected (NO in step S401), the process proceeds to step S410, where all three icons shown in FIG. 8 corresponding to the flicker reduction processing means are turned off, and then the process ends.

[0085] On the other hand, if flicker has been detected (YES in step S401), the process proceeds to step S402, where it is determined whether or not flicker can be reduced. Here, it is determined which of the three flicker reduction processing means is effective based on the results of the determinations in steps S103 to S105 shown in Figures 4A to 4C, and if there is at least one effective flicker reduction processing means, it is determined that flicker can be reduced. On the other hand, if there is not even one effective flicker reduction processing means, it is determined that flicker cannot be reduced.

[0086] If it is determined that flicker reduction is possible (YES in step S401), the process proceeds to step S403. On the other hand, if it is determined that flicker reduction is not possible (NO in step S401), the process proceeds to step S409, where all three icons shown in Fig. 8 are displayed in gray, and then the process ends.

[0087] Steps S403 and S403a are the same as steps S302 and S302a, respectively, and therefore will be omitted. If step S403 is YES, the process proceeds to step S404, and if step S403a is YES, the process proceeds to step S405.

[0088] In step S404, it is determined whether at least one of the flicker reduction functions that execute each of the three flicker reduction processing means has already been turned on (user selected) by the user. If the user has turned on at least one of the flicker reduction functions (YES in step S404), the process proceeds to step S406. On the other hand, if the user has not turned on any of the flicker reduction functions (YES in step S404), the process proceeds to step S407.

[0089] In step S406, a function that is determined to be valid in the processing of FIGS. 4A to 4C and that is determined to be turned ON by the user in step S404 is determined to be the optimal function, and the corresponding icon is lit (fourth notification control method). Also, for a function that is determined to be valid in the processing of FIGS. 4A to 4C but that is determined to not be turned ON by the user in step S404, the corresponding icon is flashed as a warning display to the user (third notification control method). On the other hand, if a function is determined to be invalid in the processing of FIGS. 4A to 4C, regardless of the determination result in step S404, the icon corresponding to that function is grayed out to notify the user that the function is invalid (fifth notification control method). Then, this processing ends.

[0090] In step S407, the reduction method priority determination process of step S304 is performed, and the icon corresponding to the reduction method with the highest priority determined in this process is made to blink, after which the process is terminated.

[0091] Steps S405 and S408 are the same as steps S304 and S305, and therefore will be omitted.

[0092] FIG. 8 is an image diagram showing an example of icon display by flicker notification unit 115 in step S406 of FIG.

[0093] As shown in Fig. 8, flicker notification unit 115 displays three icons labeled "accum," "timing," and "gain" vertically arranged from top to bottom in the upper right corner of the liquid crystal screen of display unit 117, similar to Fig. 6. These three icons are the same as the icons labeled in the same way in Fig. 6, so a description thereof will be omitted.

[0094] In the example of FIG. 8, the "accum" icon is grayed out, the "timing" icon is blinking, and the "gain" icon is lit. An example of the icon display in the process of FIG. 7 is when a moving subject is being photographed in a 100 Hz flicker environment, the accumulation time (Tv) is set to 1 / 1000, and of the three flicker reduction functions, only the image correction gain reduction function is set to On. In this example, the user has set the accumulation time to 1 / 1000, which is shorter than the flicker frequency, and it is determined in step S104 that the accumulation time reduction processing means is not enabled, so the "accum" icon is grayed out. Note that, for functions determined to be ineffective in steps S103 to S105, regardless of whether the function is set to On or Off by the user, the function is set to Off, and the corresponding icon is grayed out. Furthermore, it is determined in step S103 that the shooting timing reduction processing means is enabled, but the shooting timing reduction function is not set to On by the user, so the "timing" icon is blinking, also as a warning. On the other hand, since the reduction processing means using image correction gain is determined to be effective in step S105 and the reduction function using image correction gain is set to On by the user, the icon with the word "gain" is lit, indicating that it is optimal.

[0095] As described above, in order to indicate the status of the three functions, the corresponding icons are either lit or unlit in the first embodiment, whereas in the present embodiment, the corresponding icons are either lit, unlit, flashing, or grayed out.

[0096] This makes it possible to understand the situation taking into account the shooting environment and current camera settings, such as whether flicker has not been detected, whether the reduction function has not been enabled, or whether there is no shooting method that can reduce it in the first place, etc. This makes it clearer what operations the user should perform to take the photograph they intend.

[0097] (Other embodiments) The present invention can also be realized by supplying a program that realizes one or more functions of the present embodiment to a system or device via a network or a recording medium, and having one or more processors in the computer of the system or device read and run the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0098] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention.

[0099] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention.

[0100] The disclosure of this embodiment includes the following configuration, method, and program. (Configuration 1) An imaging device comprising: an imaging means for imaging a subject and obtaining an image signal; a detection means for detecting light source information of the light source at the time of imaging from the image signal; a selection means for selecting a reduction processing means from the plurality of reduction processing means that is effective in reducing the influence of the flicker light source based on the detected light source information if the light source at the time of imaging is the flicker light source; and a notification means for notifying a user of the selected reduction processing means. (Configuration 2) The imaging device described in Configuration 1, characterized in that the light source information includes at least one of the period, phase, and waveform of the change in brightness of the flickering light source when the light source at the time of imaging is the flickering light source. (Configuration 3) The imaging device according to configuration 1 or 2, further comprising a timing calculation means for calculating a shooting timing that can reduce the influence of the flicker light source from the light source information, and the plurality of reduction processing means includes a means for performing imaging control at the calculated shooting timing. (Configuration 4) The imaging device described in any one of configurations 1 to 3, further comprising an accumulation time calculation means for calculating an accumulation time capable of reducing the influence of the flickering light source from the light source information, and the plurality of reduction processing means includes a means for performing imaging control using the calculated accumulation time. (Configuration 5) An imaging device described in any one of configurations 1 to 4, further comprising a correction calculation means for calculating an image correction gain that can reduce the influence of the flickering light source from the light source information, and the plurality of reduction processing means includes a means for controlling the application of the calculated image correction gain to the image signal. (Configuration 6) The imaging device according to any one of configurations 1 to 5, wherein the notification means has a plurality of notification control methods. (Configuration 7) The imaging device described in Configuration 6, characterized in that the plurality of notification control methods include a first notification control method of notifying all of the reduction processing means selected by the selection means when at least one of the plurality of reduction processing means is selected by the user to perform imaging. (Configuration 8) The imaging device described in Configuration 6 further comprises a determination means for determining the reduction processing means that is most effective in reducing the influence of flickering light sources from the plurality of reduction processing means according to the settings of the imaging device, and the plurality of notification control methods include a second notification control method for notifying the user of the reduction processing means determined by the determination means when imaging is performed using the reduction processing means determined by the determination means. (Configuration 9) The imaging device according to configuration 8, characterized in that the determination means determines the most effective reduction processing means depending on whether the accumulation time is set by the user or whether the accumulation time that can reduce the influence of the flicker light source is calculated from the light source information. (Configuration 10) The imaging device according to configuration 8 or 9, wherein the determining means determines the most effective reduction processing means depending on whether the subject being photographed is a moving subject or not. (Configuration 11) An imaging device according to any one of configurations 8 to 10, characterized in that the most effective reduction processing means is determined depending on whether the period of change in brightness of the flickering light source is equal to or longer than a predetermined time. (Configuration 12) The imaging device according to any one of configurations 8 to 11, characterized in that the most effective reduction processing means is determined depending on whether the ISO used for shooting is equal to or higher than a predetermined value. (Configuration 13) The imaging device described in Configuration 6, characterized in that the plurality of notification control methods include a third notification control method that, when there is a reduction processing means among the plurality of reduction processing means that has been selected by the user in advance as a reduction processing means to be used for imaging, displays a warning for a reduction processing means that has been selected by the selection means as an effective reduction processing means but has not been selected by the user. (Configuration 14) An imaging device according to configuration 13, characterized in that it includes a fourth notification control method for notifying the user that, when there is a reduction processing means selected by the selection means as an effective reduction processing means and selected by the user, the reduction processing means is optimal. (Configuration 15) An imaging device as described in Configuration 13, characterized in that if there is a reduction processing means that is not selected by the selection means as an effective reduction processing means, the imaging device includes a fifth notification control method that notifies the user that the reduction processing means is not effective, regardless of whether the user has selected it or not. (Method 1) A control method characterized by comprising: an imaging step of imaging a subject to obtain an image signal; a detection step of detecting light source information of the light source at the time of imaging from the image signal; a selection step of selecting, if the light source at the time of imaging is the flicker light source, from the plurality of reduction processing means based on the detected light source information, a reduction processing means that is effective in reducing the influence of the flicker light source; and a notification step of notifying a user of the selected reduction processing means. (Program 1) A program for causing a computer to function as each of the means of the imaging device described in any one of configurations 1 to 15. [Explanation of symbols]

[0101] 100 digital cameras 101 Lens Group 102 Lens control unit 103 Image sensor 104 Signal Processing Unit 105 Recording processing section 106 Recording Media 107 Camera control unit 108 Operation section 109 Shooting timing calculation unit 110 Accumulation time calculation unit 111 Flicker correction calculation unit 112 Exposure control unit 113 Flicker detection unit 114 Flicker reduction processing determination unit 115 Flicker Notification Unit 116 Motion detection unit 117 Display section

Claims

1. an imaging means for imaging a subject and obtaining an image signal; a detection means for detecting light source information of a light source at the time of capturing an image from the image signal; a selection means for selecting, when the light source at the time of capturing the image is a flicker light source, a reduction processing means that is effective in reducing the influence of the flicker light source from among a plurality of flicker reduction processing means based on the detected light source information; a notification means for notifying a user of the selected reduction processing means; An imaging device comprising:

2. 2. The imaging device according to claim 1, wherein, when the light source used during imaging is the flickering light source, the light source information includes at least one of a period, a phase, and a waveform of the brightness of the flickering light source.

3. further comprising a timing calculation means for calculating, from the light source information, a photographing timing that can reduce the influence of the flicker light source; 2. The imaging device according to claim 1, wherein the plurality of reduction processing means includes a means for performing imaging control at the calculated imaging timing.

4. further comprising an accumulation time calculation means for calculating an accumulation time capable of reducing the influence of the flicker light source from the light source information; 2. The imaging apparatus according to claim 1, wherein the plurality of reduction processing means includes a means for performing imaging control using the calculated accumulation time.

5. a correction calculation means for calculating an image correction gain that can reduce the influence of the flicker light source from the light source information; 2. The imaging apparatus according to claim 1, wherein the plurality of reduction processing means includes a control means for applying the calculated image correction gain to the image signal.

6. 2. The imaging device according to claim 1, wherein the notification means has a plurality of notification control methods.

7. The imaging device according to claim 6, characterized in that the plurality of notification control methods include a first notification control method of notifying all of the reduction processing means selected by the selection means when at least one of the plurality of reduction processing means is selected by the user to perform imaging.

8. a determining unit that determines which of the plurality of reduction processing units is most effective in reducing the influence of the flickering light source in accordance with a setting of the imaging device, The imaging device according to claim 6, characterized in that the plurality of notification control methods include a second notification control method for notifying a user of the reduction processing means determined by the determination means when imaging is performed using the reduction processing means determined by the determination means.

9. 9. The imaging device according to claim 8, wherein the determining means determines the most effective reduction processing means depending on whether an accumulation time is set by a user or whether an accumulation time capable of reducing the influence of the flicker light source is calculated from the light source information.

10. 9. The image pickup apparatus according to claim 8, wherein said determining means determines the most effective reduction processing means depending on whether the subject being photographed is a moving subject or not.

11. 9. The imaging device according to claim 8, wherein the most effective reduction processing means is determined depending on whether the period of change in brightness of the flickering light source is equal to or longer than a predetermined time.

12. 9. The image pickup apparatus according to claim 8, wherein the most effective reduction processing means is determined depending on whether or not the ISO used for photographing is equal to or higher than a predetermined value.

13. The imaging device described in claim 6, characterized in that the multiple notification control methods include a third notification control method in which, when there is a reduction processing means among the multiple reduction processing means that has been selected by the user in advance as a reduction processing means to be used for imaging, a warning is displayed for a reduction processing means that has been selected by the selection means as an effective reduction processing means but has not been selected by the user.

14. The imaging device according to claim 13, further comprising a fourth notification control method for notifying the user that a reduction processing means selected by the selection means as an effective reduction processing means and selected by the user is optimal.

15. The imaging device described in claim 13, characterized in that it includes a fifth notification control method that, if there is a reduction processing means that is not selected by the selection means as an effective reduction processing means, notifies the user that the reduction processing means is not effective, regardless of whether the user has selected it or not.

16. an imaging step of imaging an object to obtain an image signal; a detection step of detecting light source information of a light source at the time of image capture from the image signal; a selection step of selecting a reduction processing means that is effective in reducing the influence of the flickering light source from among the plurality of reduction processing means based on the detected light source information, if the light source at the time of capturing the image is the flickering light source; a notification step of notifying a user of the selected reduction processing means; A control method comprising:

17. A program for causing a computer to function as each of the means of the imaging device according to claim 1.

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