Image capture device, image capture device control method and program

Abstract

To enable proper mode switching control even when a visible light sensor and its surroundings are stained or the like.SOLUTION: An imaging apparatus includes control means for switching between a first mode for photographing with an infrared light removal filter inserted on the front side of an imaging element and a second mode for photographing with the infrared light removal filter removed, and acquisition means for acquiring a sensor value representing the brightness of visible light detected by a visible light sensor in a photographic environment. When the control means is in the first mode, the control means determines whether the visible light sensor can normally acquire the brightness of visible light on the basis of a result of comparison between the sensor value acquired by the acquisition means and an estimated value of the brightness of visible light in the photographic environment.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control technique for an imaging device capable of switching between imaging modes. [Background technology]

[0002] Network-connected cameras (hereafter referred to as network cameras) have been used for a long time. Security network cameras, in particular, offer two modes: a day mode, in which an IR-cut filter is placed on the front side of the image sensor to capture only visible light, and a night mode, in which the IR-cut filter is removed to capture infrared light for improved visibility in low-light environments. Network cameras with day and night mode functions often have a mode-switching function called ADN (auto day / night), which acquires brightness values ​​from captured images and automatically switches between day mode and night mode based on those brightness values. Some security network cameras also have an infrared illumination function that turns on the infrared illumination when capturing images in night mode, enabling brighter images even in dark environments. However, if the mode is switched based solely on the brightness value of the captured image, it is impossible to determine whether the shooting environment is becoming brighter or whether the shooting environment remains dark but has become brighter due to the infrared illumination. For this reason, most network cameras with infrared illumination also have a visible light sensor that determines that the shooting environment is becoming brighter and switches to day mode when the detected value of the visible light sensor is above a threshold.

[0003] Patent Document 1 discloses a technology that enables appropriate ADN control based on the comparison result between a switching evaluation value (learned value) when switching from day mode to night mode last time and a current switching evaluation value. Patent Document 1 discloses a configuration in which if the comparison result between the previous switching evaluation value and the current switching evaluation value is within a predetermined range, it is determined that switching occurred at the intended environmental brightness, and if it is greater than the predetermined range, it is determined that switching occurred at an unintended brightness. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-11635 Summary of the Invention [Problem to be solved by the invention]

[0005] In network cameras equipped with the aforementioned infrared illumination function and visible light sensor, the visible light sensor itself and its surroundings can become dirty. Network cameras installed outdoors in particular often become dirty due to wind and rain. When the visible light sensor or its surroundings become dirty, the detection value of the visible light sensor becomes smaller than the expected value for the brightness of visible light in the shooting environment, making it impossible to perform appropriate mode switching control.

[0006] Therefore, an object of the present invention is to enable appropriate mode switching control even if the visible light sensor or its surroundings is soiled. [Means for solving the problem]

[0007] The imaging device of the present invention includes a control means for switching between a first mode in which an image is captured with an infrared light removal filter inserted in front of an imaging element and a second mode in which an image is captured with the infrared light removal filter removed, and an acquisition means for acquiring a sensor value representing the brightness of visible light detected by a visible light sensor in a capturing environment, wherein the control means: When the sensor value acquired by the acquisition means becomes equal to or greater than a predetermined mode transition threshold value while in the second mode, switching to the first mode is performed; When in the first mode, the sensor value acquired by the acquisition means is compared with an estimated value of the brightness of visible light in the shooting environment. When the difference value becomes equal to or greater than a predetermined difference threshold, the predetermined mode transition threshold is reset, and when the predetermined mode transition threshold is reset, the predetermined mode transition threshold is set lower than before the reset. It is characterized by: [Effects of the Invention]

[0008] According to the present invention, even if the visible light sensor or its surroundings becomes dirty, appropriate mode switching control is possible. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating an example of a schematic configuration of an imaging device according to a first embodiment. [Figure 2] 4 is a flowchart of a control process according to the first embodiment. [Figure 3] 10 is a flowchart of a control process according to a second embodiment. [Figure 4] 10 is a flowchart of a control process according to a third embodiment. [Figure 5] FIG. 11 is a diagram illustrating an example of a notification according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments do not limit the present invention, and not all of the combinations of features described in the present embodiments are necessarily essential to the solution of the present invention. The configurations of the embodiments may be modified or changed as appropriate depending on the specifications of the device to which the present invention is applied and various conditions (such as usage conditions and usage environment). Furthermore, a configuration may be achieved by appropriately combining parts of each of the embodiments described below. In the following embodiments, the same components will be described with the same reference symbols.

[0011] First Embodiment 1 is a block diagram showing an example of the configuration of an imaging device 100 according to the first embodiment. In this embodiment, the imaging device 100 is assumed to be a network camera, for example. Note that the configuration and description of the network to which the network camera is connected and devices connected to the network camera of this embodiment via the network will be omitted.

[0012] 1 is communicably connected to a display unit 105. Note that, although the present embodiment describes an example in which the imaging device 100 and the display unit 105 are separate entities, the imaging device 100 and the display unit 105 may be integrated into one unit. The imaging device 100 can transmit captured image signals via the communication unit 103 to the display unit 105 or to an external device such as a server (not shown).

[0013] The imaging unit 101 captures light from the outside and captures an image to generate an image signal of a subject, etc. The imaging unit 101 includes a lens group, an IR cut filter (Infrared Ray Cut Filter: a filter for removing infrared light), an image sensor, a CDS circuit, an AGC amplifier, and an A / D converter (not shown). The lens group also includes an aperture mechanism.

[0014] The IR cut filter is removably attached to the front side of the image sensor, and the IR cut filter is inserted and removed by controlling an IRCF insertion / removal mechanism (not shown) by a control unit 104 (described later). The image capture device 100 has the functions of a first mode in which the IR cut filter is placed on the front side of the image sensor to capture only visible light for image capture, and a second mode in which the IR cut filter is removed to capture infrared light for improved visibility in low-light environments. In the following description of the present embodiment, the first mode in which image capture is performed with the IR cut filter inserted on the front side of the image sensor is referred to as day mode, and the second mode in which image capture is performed with the IR cut filter removed from the front side of the image sensor is referred to as night mode.

[0015] In day mode, an optical image of a subject or the like that passes through the lens group and the IR cut filter is formed on an image sensor consisting of a CCD sensor or CMOS sensor. On the other hand, in night mode, the IR cut filter is removed from the front of the image sensor, and an optical image of a subject or the like that passes through the lens group is formed on the image sensor. In both day mode and night mode, the image sensor photoelectrically converts the formed optical image and outputs it as an electrical signal (analog image signal).

[0016] The CDS (Correlated Double Sampling) circuit performs correlated double sampling processing on the electrical signal input from the image sensor. The AGC (Automatic Gain Control) amplifier performs gain processing (amplification processing) on ​​the electrical signal input from the CDS circuit. The A / D converter converts the electrical signal (analog image signal) that has been gain-processed (amplified) by the AGC amplifier into a digital image signal and outputs it.

[0017] The signal processing unit 102 performs image signal processing such as WB (white balance) processing and NR (noise reduction) processing on the digital image signal output from the imaging unit 101, and outputs image data. The signal processing unit 102 also performs processing to calculate a luminance value from the digital image signal input from the imaging unit 101, that is, the luminance value of the captured image.

[0018] The display unit 105 acquires, via the communication unit 103, image data that has been subjected to image signal processing by the signal processing unit 102, and displays an image based on the image data. The display unit 105 also displays a UI (user interface) screen. The display unit 105 may be configured as part of an external terminal that is capable of issuing control instructions to the imaging device 100. The display unit 105 may also be a touch panel or a PC screen, and may be configured to display a UI (user interface) screen that generates instructions to the imaging device 100 based on user operations via the touch panel or PC screen.

[0019] The control unit 104 is configured to include a CPU, ROM, RAM, etc. (not shown). The CPU is a central processing unit that controls each functional unit of the imaging device 100 and performs various calculations required for the control program according to a control program loaded from the ROM. The ROM is a rewritable memory that does not require a storage operation, and stores the control program executed by the CPU and various constant values ​​required for program execution. The RAM is a rewritable memory that requires a storage operation, and is an area for storing various temporary data required for program execution.

[0020] The communication unit 103 transmits the image data processed by the signal processing unit 102 to the display unit 105. The communication unit 103 can also transmit the image data processed by the signal processing unit 102 to an external client device, a server, or the like. The display unit 105, which is the output destination of the image data, may be a liquid crystal display (LCD) built into the imaging device 100 or an external display. The communication unit 103 can also acquire control information for the imaging device 100 instructed from an external terminal including the display unit 105.

[0021] The visible light level acquisition unit 107 is a sensor value acquisition unit that acquires the visible light level detected by a visible light sensor (not shown) included in the image capture device 100, i.e., a value representing the brightness of visible light detected by the visible light sensor in the image capture environment. In this embodiment, the value representing the brightness of visible light detected by the visible light sensor in the image capture environment will hereinafter be referred to as the visible light sensor value.

[0022] The switching determination unit 106 determines whether to switch the mode of the imaging device 100 to day mode or night mode. That is, the switching determination unit 106 makes the mode switching determination based on the luminance value of the captured image calculated by the signal processing unit 102 and the visible light sensor value of the imaging environment acquired from the visible light sensor by the visible light level acquisition unit 107. The mode switching determination process in the switching determination unit 106 will be described in detail later.

[0023] If the result of the mode switching determination by the switching determination unit 106 is, for example, a result indicating a transition from day mode to night mode, the control unit 104 controls the IRCF insertion / removal mechanism to remove the IR cut filter from the front side of the image sensor in the image capture unit 101. If the result of the mode switching determination is a result indicating a transition from night mode to day mode, the control unit 104 controls the IRCF insertion / removal mechanism to place the IR cut filter on the front side of the image sensor in the image capture unit 101. Note that, although the example in this embodiment shows the control unit 104 controlling the IRCF insertion / removal mechanism of the image capture unit 101, the switching determination unit 106 may also control the IRCF insertion / removal mechanism.

[0024] The illumination control unit 108 controls the turning on and off of an infrared illumination provided in the imaging device 100. The infrared illumination may be provided in the imaging device 100 or may be connected to the imaging device 100 as an external device. When the mode switching determination result indicates a transition from day mode to night mode, the control unit 104 instructs the illumination control unit 108 to turn on (emit) the infrared illumination. Upon receiving this instruction, the illumination control unit 108 controls the infrared illumination to turn on. Furthermore, when the mode switching determination result indicates a transition from night mode to day mode, the control unit 104 instructs the illumination control unit 108 to turn off the infrared illumination. Upon receiving this instruction, the illumination control unit 108 controls the infrared illumination to turn off.

[0025] In this way, in the image capturing device 100 of this embodiment, in the night mode, the IR cut filter is removed from the front side of the image capturing element and the infrared illumination is turned on (emitted), whereas in the day mode, the image capturing device 100 inserts the IR cut filter in front of the image capturing element and turns off the infrared illumination.

[0026] 1 shows an example in which the control unit 104, switching determination unit 106, illumination control unit 108, and visible light level acquisition unit 107 are each configured as separate functional units, and the control unit 104 includes a CPU and controls the other functional units by executing a control program. However, the present embodiment is not limited to this example. For example, the CPU may execute the control program of the present embodiment to not only realize the function of the control unit 104, but also realize the functions of the switching determination unit 106, illumination control unit 108, and visible light level acquisition unit 107.

[0027] Fig. 2 is a flowchart showing the flow of ADN (auto day / night) control in the image capture device 100 of the first embodiment. The flowchart in Fig. 2 shows the processing procedures executed by the functional units of the image capture device 100 of Fig. 1. The processing of the flowchart shown in Fig. 2 is realized by loading a control program according to this embodiment stored in ROM into RAM and executing the control program with a CPU.

[0028] 2, a case will be described in which the image capture device 100 transitions from night mode to day mode. Since the shooting environment is currently dark, in step S200, the image capture device 100 is performing shooting in night mode with an IR cut filter placed on the front side of the image sensor and infrared illumination turned on.

[0029] In step S201, visible light level acquisition unit 107 acquires a visible light sensor value from the visible light sensor, and switching determination unit 106 determines whether the visible light sensor value is equal to or greater than a predetermined threshold. The predetermined threshold used by switching determination unit 106 in step S201 is a threshold set in advance as a value for determining whether to transition from night mode to day mode, and is referred to as the mode transition threshold in this embodiment. If the visible light sensor value is less than the mode transition threshold, switching determination unit 106 continues the determination process of step S201. In other words, if the visible light sensor value is less than the mode transition threshold, imaging device 100 continues shooting in night mode. On the other hand, if the visible light sensor value is equal to or greater than the mode transition threshold, imaging device 100 performs the processes from step S202 onwards.

[0030] In step S202, the switching determination unit 106 determines that the imaging device 100 should be transitioned to day mode. Then, upon receiving the determination result of the switching determination unit 106 that the imaging device 100 should be transitioned to day mode, the control unit 104 controls the IRCF insertion / removal mechanism of the imaging unit 101 to insert an IR cut filter on the front side of the imaging element. The control unit 104 also sends an instruction to the illumination control unit 108 to turn off the infrared illumination, and the illumination control unit 108 controls to turn off the infrared illumination. As a result, the imaging device 100 will perform imaging in day mode.

[0031] In normal ADN control, when the visible light sensor value changes from below the mode transition threshold to above the mode transition threshold, it is assumed that the shooting environment has become brighter, and the camera will transition from night mode to day mode. However, if dust or dirt has accumulated on the visible light sensor or its surroundings, preventing the camera from obtaining a normal visible light sensor value corresponding to the brightness of the shooting environment, the camera will not be able to transition to day mode even though the shooting environment has actually become brighter.

[0032] Therefore, in this embodiment, in step S203, immediately after transitioning from night mode to day mode, the control unit 104 acquires exposure parameters, such as aperture value, shutter speed, and gain value during gain processing, from the image capture unit 101. The control unit 104 then estimates the brightness of visible light in the image capture environment based on the exposure parameters acquired from the image capture unit 101. That is, the control unit 104 functions as an estimate value acquisition unit that acquires an estimate of the brightness of visible light in the image capture environment. Furthermore, the control unit 104 compares the estimate of the brightness of visible light in the image capture environment with the visible light sensor value acquired from the visible light sensor by the visible light level acquisition unit 107. In this embodiment, the control unit 104 calculates a difference between the estimate of the brightness of visible light in the image capture environment and the visible light sensor value as a value representing the comparison result. The control unit 104 then determines whether the difference between the estimate of the brightness of visible light in the image capture environment and the visible light sensor value is equal to or greater than a predetermined threshold. In this embodiment, a predetermined threshold value that is set in advance for comparing the difference between the estimated value of the brightness of visible light in the shooting environment and the visible light sensor value is referred to as the “difference threshold value.” If the difference between the estimated value of the brightness of visible light and the visible light sensor value is equal to or greater than the difference threshold value, the control unit 104 executes the process of step S204.

[0033] If the process proceeds to step S204 because the difference value is equal to or greater than the difference threshold, the control unit 104 determines that the visible light sensor has not acquired a normal visible light sensor value, and executes step S205. On the other hand, if the difference value is less than the difference threshold in step S203, the control unit 104 determines that the visible light sensor has acquired a normal visible light sensor value, and controls each functional unit to continue shooting in day mode.

[0034] In step S205, the control unit 104 resets the mode transition threshold used when transitioning from the night mode to the day mode. For example, assume that the mode transition threshold before resetting was 10 lx (lx: lux), the visible light sensor value acquired immediately after transitioning to day mode was 10 lx, and the brightness of visible light in the shooting environment estimated at that time was 20 lx. In this case, when the brightness of visible light in the shooting environment reaches 20 lx, the visible light sensor acquires a visible light sensor value indicating that the brightness of visible light in the shooting environment is 10 lx. This value exceeds the mode transition threshold, resulting in a transition from night mode to day mode. In this case, the visible light sensor has acquired a visible light sensor value that is only half the brightness of visible light in the actual shooting environment. In this way, when the visible light sensor value is half the estimated value of the brightness of visible light in the actual shooting environment, control unit 104 resets the mode transition threshold to half the value, that is, to 5 lx, which is half of 10 lx. That is, if it is assumed that a transition from night mode to day mode will occur when the actual brightness of visible light in the shooting environment reaches 10 lx, and the visible light sensor can only obtain a value that is half the brightness of the actual visible light, the mode transition threshold is reset to 5 lx. This enables a transition from night mode to day mode to be achieved when the actual brightness of visible light in the shooting environment reaches 10 lx. In this way, the imaging device of this embodiment resets the mode transition threshold, making it possible to transition from night mode to day mode at an appropriate time even if the visible light sensor value is no longer the expected value.

[0035] The above-described resetting of the mode transition threshold may be performed by other methods, such as lowering the threshold level selectable by the user via the UI by one level. In addition, in this embodiment, a method for estimating the brightness of the shooting environment from exposure parameters is given as an example, but other methods may be used as long as they can estimate the brightness of the shooting environment and compare it with the visible light sensor value. Furthermore, the mode transition threshold and the difference threshold may be configured to be set in advance depending on the accuracy of brightness estimation of the shooting environment and the performance of the visible light sensor, or may be configured to be set by the user on the UI. Furthermore, in this embodiment, the determination is made immediately after the mode transition from night mode to day mode, but the timing of the determination may vary depending on the specifications and configuration of the product as long as it is in day mode.

[0036] Furthermore, if the accuracy of estimating the brightness of the shooting environment or the performance of the visible light sensor is not high, it may be determined that the visible light sensor value has not acquired a normal value based on the number of times the difference value between the brightness of the shooting environment and the visible light sensor value has exceeded the difference threshold. In this case, in step S203, the control unit 104 counts the number of times the difference value between the brightness of the shooting environment and the visible light sensor value has exceeded the difference threshold. Then, if the counted number exceeds a predetermined number threshold, the control unit 104 determines that the visible light sensor value has not acquired a normal value in the process of step S204. In this way, by making a determination based on a comparison of the number of times the difference value between the brightness of the shooting environment and the visible light sensor value has exceeded the difference threshold with a preset number threshold, the influence of disturbances can be reduced.

[0037] As described above, in the imaging device 100 of this embodiment, which is equipped with an ADN function and a visible light sensor, even if the visible light sensor becomes dirty due to wind, rain, dust, etc. and the visible light sensor value cannot be obtained normally, it is possible to perform appropriate ADN control. As described above, after the mode transition threshold is reset, if the wind and rain subside or the dirt is removed and the visible light sensor is able to acquire normal values, the mode transition threshold must be restored to its state before resetting. Therefore, if the difference between the brightness of the shooting environment and the visible light sensor value falls below the difference threshold, the mode transition threshold may be restored to the reset value. Alternatively, if the network camera is restarted, the mode transition threshold may be restored to the threshold before resetting (for example, the initial value).

[0038] <Second embodiment> In the first embodiment, the visible light sensor value is compared with the brightness of the shooting environment estimated from the captured image and exposure parameters, and the difference between the comparison results is calculated to determine whether the visible light sensor value is being acquired correctly. However, if the visible light sensor or its surroundings become dirty due to wind and rain, causing the visible light sensor value to be lower than expected, the visible light sensor value does not always decrease by a constant value. In other words, the degree of dimming at which the visible light sensor value decreases may differ between a very bright shooting environment and a brightness near the mode transition threshold for switching from night mode to day mode. Therefore, when resetting the mode transition threshold from night mode to day mode, it is desirable to determine whether the visible light sensor value is normal at a brightness near the mode transition threshold from night mode to day mode whenever possible.

[0039] Therefore, in the second embodiment, a case will be described in which it is determined whether the visible light sensor value is normal near the mode transition threshold from night mode to day mode. Note that the same components and parts that perform the same processes as those in the first embodiment will be assigned the same reference numerals, and their description will be omitted.

[0040] Fig. 3 is a flowchart showing the flow of ADN control in the imaging device 100 according to the second embodiment. The flowchart in Fig. 3 shows the processing procedures executed by the functional units of the imaging device 100 in Fig. 1. The processing of the flowchart shown in Fig. 3 is realized by loading a control program according to this embodiment stored in ROM into RAM and executing the control program with a CPU. Note that the same processing steps as those in the flowchart in Fig. 2 described above are given the same reference numerals, and their description will be omitted.

[0041] The processes from step S200 to step S202 are the same as those in the first embodiment, and therefore description thereof will be omitted. In the second embodiment, after step S202, the imaging device 100 executes the process of step S301.

[0042] In step S301, the control unit 104 acquires visible light sensor values ​​before and after the mode transition from night mode to day mode, calculates the difference between the visible light sensor values ​​before and after the mode transition, and compares this difference with a predetermined threshold. In this embodiment, the predetermined threshold set in advance for comparison with the difference between the visible light sensor values ​​before and after the mode transition is referred to as the "pre-post difference threshold." If the difference between the visible light sensor values ​​before and after the mode transition is less than the pre-post difference threshold, the control unit 104 proceeds to step S203 and subsequent steps, and performs the same processing as in the first embodiment from step S203 to step S205. Here, a small difference between the visible light sensor values ​​before and after the mode transition can be determined to indicate that the shooting environment gradually became brighter, and therefore it can be determined that the night mode was switched to day mode near the mode transition threshold from night mode to day mode.

[0043] On the other hand, if the difference between the visible light sensor values ​​before and after the mode transition is equal to or greater than the before-and-after difference threshold, it can be assumed that the shooting environment suddenly became brighter. Therefore, the control unit 104 determines that the mode was switched to day mode in an environment brighter than the vicinity of the mode transition threshold to day mode, and controls each unit to continue shooting in day mode without resetting the mode transition threshold to day mode.

[0044] The threshold for the difference between the visible light sensor values ​​before and after the mode transition may be set in advance based on the performance of the imaging device, or may be configured to be set by the user on the UI.

[0045] As described above, according to the second embodiment, it is possible to determine whether the visible light sensor value is normal at a brightness near the threshold for mode transition from night mode to day mode.

[0046] <Third embodiment> In the first embodiment, whether the visible light sensor value has been acquired correctly is determined based on the difference between the comparison result between the visible light sensor value and the estimated brightness of the shooting environment, and the mode transition threshold from night mode to day mode can be reset based on the determination result. Here, if the visible light sensor or its surroundings become dirty due to wind, rain, etc., the degree of dirt and the effect of the dirt on the visible light sensor vary, so in order to demonstrate the original ADN performance, it is desirable for the user to remove the dirt from the visible light sensor.

[0047] Therefore, in the third embodiment, if the determination result of whether the visible light sensor value is being acquired normally indicates that it is not normal, the user is notified that the visible light sensor may be dirty. Note that the same reference numerals are used to designate components that have the same configurations and perform the same processes as those in the first embodiment, and descriptions thereof will be omitted.

[0048] Fig. 4 is a flowchart showing the flow of ADN control in the imaging device 100 according to the third embodiment. The flowchart in Fig. 3 shows the processing procedure executed by each functional unit of the imaging device 100 in Fig. 1. The processing of the flowchart shown in Fig. 3 is realized by loading a control program according to this embodiment stored in ROM into RAM and executing the control program with a CPU. Note that the same processing steps as those in the flowchart in Fig. 2 described above are given the same reference numerals, and their description will be omitted.

[0049] The processes from step S200 to step S204 are the same as those in the first embodiment, and therefore description thereof will be omitted. In the third embodiment, after step S204, the imaging device 100 executes the process of step S401.

[0050] When the process proceeds to step S401, the control unit 104 generates a message such as "The visible light sensor value has not acquired a normal value," and causes the message to be displayed on the display unit 105 via the communication unit 103. As a result, the user is notified of the message such as "The visible light sensor value has not acquired a normal value." Note that, although the third embodiment has exemplified an example in which the user is notified by displaying a message on the display unit 105, other configurations and methods may also be used.

[0051] 5A and 5B are diagrams showing examples of the display screen and notification message of the display unit 105. FIG. 5A shows an example of a notification in which text 501 is displayed on a screen 500 using an overlay. Text 501 is an example, and other words and expressions may be used. For example, the wording "visible light sensor" in text 501 may be changed to "illuminance sensor" or "light sensor," which are considered to be easier for the user to understand, and the wording "dirty" may be changed to "please clean the surface of the camera body."

[0052] 5(b) is an example of a notification that is made by displaying an ADN icon 511 on the screen 500. The ADN icon 511 is displayed on the screen 500 and further flashes to notify that there is an abnormality in the visible light sensor. While the ADN icon is used in this example, if there is an icon that represents a visible light sensor, that may be used, or another icon may be used as long as it conveys the content of the message to the user.

[0053] In this way, according to the third embodiment, it is possible to notify the user that the visible light sensor may be dirty.

[0054] The present invention can also be realized by supplying a program that realizes one or more of the functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more of the functions. The above-described embodiments are merely examples of specific implementations of the present invention, and the technical scope of the present invention should not be construed as being limited by these embodiments. In other words, the present invention can be implemented in various forms without departing from its technical concept or main features. [Explanation of symbols]

[0055] 100: imaging device, 101: imaging unit, 102: signal processing unit, 104: control unit, 105: display unit, 106: switching determination unit, 107: visible light level acquisition unit, 108: lighting control unit

Claims

1. a control means for switching between a first mode in which an image is taken with an infrared light removal filter inserted in front of the image sensor and a second mode in which an image is taken with the infrared light removal filter removed; an acquisition means for acquiring a sensor value representing the brightness of visible light detected by the visible light sensor in the shooting environment; The control means When the sensor value acquired by the acquisition means becomes equal to or greater than a predetermined mode transition threshold value while in the second mode, switching to the first mode is performed; When the first mode is selected, if a difference between the sensor value acquired by the acquisition means and an estimated value of the brightness of visible light in the shooting environment becomes equal to or greater than a predetermined difference threshold, the predetermined mode transition threshold is reset; The imaging device according to claim 1, wherein when the predetermined mode transition threshold is reset, the predetermined mode transition threshold is set lower than before the resetting.

2. 2. The imaging device according to claim 1, wherein the control means obtains an estimated value of the brightness of visible light in the imaging environment from an image captured by imaging or from exposure parameters used during imaging.

3. 2. The imaging device according to claim 1, wherein, after resetting the predetermined mode transition threshold, if a difference between the sensor value acquired by the acquisition means in the first mode and the estimated value becomes less than a predetermined difference threshold, the control means returns the predetermined mode transition threshold to a value before the resetting.

4. 2. The imaging device according to claim 1, wherein, when switching from the second mode to the first mode, the control unit calculates a difference between the sensor values ​​acquired by the acquisition unit before and after the switching, and if the difference between the sensor values ​​before and after the switching is less than a predetermined before-and-after difference threshold, determines whether the visible light sensor is successfully acquiring the brightness of the visible light.

5. 2. The imaging device according to claim 1, wherein, when the difference between the sensor value acquired by the acquisition means and the estimated value of the brightness of visible light in the shooting environment is equal to or greater than a predetermined difference threshold value, the control means determines that the visible light sensor is not correctly acquiring the brightness of the visible light, and notifies the user of the result of the determination.

6. 2. The imaging apparatus according to claim 1, further comprising illumination control means for turning on an infrared illumination in the second mode and turning off the infrared illumination in the first mode.

7. a control step of switching between a first mode in which an image is captured with an infrared light removal filter inserted in front of the image sensor and a second mode in which an image is captured with the infrared light removal filter removed; an acquisition step of acquiring a sensor value representing the brightness of visible light detected by the visible light sensor in the shooting environment, In the control step, When the sensor value acquired in the acquiring step is equal to or greater than a predetermined mode transition threshold value in the second mode, the mode is switched to the first mode; When the first mode is selected, if a difference between the sensor value acquired in the acquisition step and an estimated value of brightness of visible light in the shooting environment becomes equal to or greater than a predetermined difference threshold, resetting the predetermined mode transition threshold; A control method for an imaging device, comprising: when resetting the predetermined mode transition threshold, setting the predetermined mode transition threshold to a value lower than that before the resetting.

8. A program for causing a computer to function as each of the means of the imaging device according to any one of claims 1 to 6.

Images