JP2020170971A - Imaging device, control method thereof, and program - Google Patents

Abstract

To provide an imaging device, a control method thereof, and a program that can reliably and quickly remove dust from an optical member mounted on the subject side of an imaging element while ensuring the image quality during live view (LV) display.SOLUTION: An imaging device 1 includes an LV display function that controls the drive of an imaging element 113 and a liquid crystal monitor 124, sequentially reads out an imaging signal from the imaging element 113 at the time interval according to the frame rate, and continuously displays a live view image on the liquid crystal monitor 124 at the update interval according to the frame rate on the basis of the imaging signal, and a dust removal function that vibrates an optical member mounted on the subject side of the imaging element 113 by controlling the application of a voltage to a piezoelectric element 111 and expanding and contracting the piezoelectric element 111 to remove dust from the optical member. When the dust removal function is executed in parallel with the execution of the LV display function, a voltage is applied to the piezoelectric element 111 during a blanking period while the imaging element 113 is being driven.SELECTED DRAWING: Figure 3

Description

The present invention relates to an image pickup device and a control method and program thereof, and more particularly to an image pickup device equipped with a dust removal function for an optical member mounted on the subject side of the image pickup device and a live view display function of a captured image, and a control method and program thereof.

Generally, an image pickup device such as a digital camera that converts an optical image of a subject into an electric signal and takes an image receives a shooting light beam by the image pickup element, and converts a photoelectric conversion signal (imaging signal) output from the image pickup element into image data. Convert and record on a recording medium such as a memory card. As such an image pickup device, for example, a CCD (Charge Coupled Device), a CMOS sensor (Complementary Metal Oxide Semiconductor), or the like is used.

Further, an optical member such as an optical low-pass filter or an infrared filter may be mounted on the subject side of the image sensor. When foreign matter such as dust adheres to the surface of such an optical member, the adhered portion becomes a black spot and is reflected in the captured image, which causes a problem that the image quality of the image deteriorates.

In order to avoid such a problem, a dust removing function is known in which the optical member is vibrated by a piezoelectric element to remove foreign substances such as dust.

On the other hand, recent digital cameras have a live view display function in which an image sensor continuously accumulates charge by exposure and reads it out as an image pickup signal, and a display device such as a liquid crystal monitor displays a live view image based on the image pickup signal. It may be installed.

Even if such a digital camera does not have an optical viewfinder, the photographer can check the subject by using the live view display function. For this reason, interchangeable-lens digital cameras that have abolished the optical viewfinder, so-called mirrorless cameras, are often equipped with a live view display function.

On the other hand, in a camera equipped with both a dust removal function and a live view display function, most of the dust removal functions use ultrasonic vibration, so if the live view display function and the dust removal function are executed in parallel, the live view will be displayed. There was a problem that the display was distorted.

This problem is caused by the fact that the voltage supplied to the piezoelectric element is high, so that the noise generated by the step-up transformer is superimposed on the imaging signal that generates the live view image.

In order to avoid such a problem, Patent Document 1 discloses a technique for executing a dust removal function during a blanking period so as not to superimpose noise on an imaging signal that generates a live view image. Here, the blanking period refers to a period between the reading time of the image pickup signal by the image sensor for one frame and the reading time of the image pickup signal by the image pickup device for the next one frame.

On the other hand, if the dust removal function is executed only during the blanking period, the execution time becomes short, and there is a possibility that foreign matter such as dust cannot be reliably removed. Therefore, in order to secure the execution time of the dust removal function, Patent Document 1 further discloses a technique for reducing the number of read lines when reading an image pickup signal from an image pickup element in order to shorten the read time of the image pickup signal for generating a live view image. Has been done.

Further, in Patent Document 1, when reading an image signal from an image sensor, the voltage supplied to the piezoelectric element is set to a low voltage to reduce the noise generated by a step-up transformer superimposed on the image signal that generates a live view image. Is disclosed.

On the other hand, in the conventional dust removal function, the resonance frequency that vibrates the vibrating object fluctuates due to changes in the environmental temperature, individual differences in the shape of the vibrating object, etc., and foreign matter such as dust adhering to the vibrating object is reliably removed. There was a problem that it could not be done.

In order to avoid this problem, Patent Document 2 divides the frequency bands into a plurality of frequency bands, combines the divided frequency bands to efficiently vibrate the vibrating object, and effectively removes dust and the like adhering to the surface thereof. A technique for removing foreign matter is disclosed.

Further, in the conventional dust removing function, there is a problem that the resonance frequency of the vibration target fluctuates due to variations in the processing accuracy of the piezoelectric element used for removing foreign substances such as dust and the manufacturing process. However, the interval between the plurality of resonance frequencies of the optical member to which the piezoelectric element is attached does not change even if there is such a variation generating factor.

Therefore, in Patent Document 3, a plurality of resonance frequencies to be vibrated are detected, and the vibration member is driven at a resonance frequency in which another resonance frequency detected is present at a frequency shifted by the above interval among the detected resonance frequencies. The technology is disclosed.

JP-A-2018-74564 Japanese Unexamined Patent Publication No. 2013-85022 Japanese Unexamined Patent Publication No. 2015-231173

However, as in Patent Document 1, if the number of read lines when reading the image pickup signal from the image pickup device is reduced while the dust removal function is being executed, it is considered that the image quality of the generated live view image is deteriorated.

Further, as in Patent Document 1, if the voltage supplied to the piezoelectric element is set to a low voltage when reading an image signal from the image sensor, the amplitude when the piezoelectric element vibrates becomes small, and the dust removing effect by the dust removing function is lowered. Is possible. Further, even if the voltage supplied to the piezoelectric element is set to a low voltage, the noise generated by the step-up transformer is not completely eliminated.

Further, when the dust removing function disclosed in Patent Document 2 and Patent Document 3 is used, foreign matter such as dust can be efficiently removed, but deterioration of the image quality of the live view display due to noise generated by the step-up transformer cannot be suppressed.

Therefore, the present invention provides an image pickup device capable of reliably and quickly removing dust from an optical member mounted on the subject side of the image pickup device while ensuring the image quality during live view display, and a control method and program thereof. The purpose is to provide.

The imaging device according to claim 1 of the present invention includes an imaging element that photoelectrically converts an optical image of a subject, accumulates a charge, and reads it out as an imaging signal, an optical member arranged on the subject side of the imaging element, and the optical. A piezoelectric element that is fixed to a member and expands and contracts when a voltage is applied, a display means, an image pickup element, and a drive of the display means are controlled, and imaging signals are sequentially read from the image pickup element at time intervals according to a frame rate. A first control means for executing a live view display function of continuously displaying a live view image by the display means at an update interval according to the frame rate based on the image pickup signal, and application of a voltage to the piezoelectric element. This is an imaging device including a second control means for performing a dust removing function of vibrating the optical member by expanding and contracting the piezoelectric element to remove dust from the optical member. In the first case where the dust removal function is executed in parallel with the execution of the live view display function by the first control means, the means applies a voltage to the piezoelectric element during the blanking period while the image pickup element is being driven. It is characterized by doing.

According to the present invention, it is possible to reliably and quickly remove dust from the optical member mounted on the subject side of the image sensor while ensuring the image quality during the live view display.

It is a block diagram which shows the main electrical structure of the image pickup apparatus which concerns on Example 1 of this invention. It is a timing chart which shows the relationship between the reading timing of the image pickup signal from the image pickup element, and the voltage application timing to a piezoelectric element at the time of the conventional live view (LV) display. It is a timing chart which shows the relationship of the operation timing of the image pickup element, the liquid crystal monitor, and the piezoelectric element which concerns on Example 1 of this invention. It is a figure for demonstrating the amplitude when the piezoelectric element vibrates at the operation timing in FIG. It is a figure for demonstrating the sweep time of the frequency of the voltage applied to a piezoelectric element at the operation timing in FIG. It is a flowchart of the parallel execution processing of the LV display function and the dust removal function which concerns on Example 1 of this invention. It is a block diagram which shows the main electrical structure of the image pickup apparatus which concerns on Example 2 of this invention. It is a timing chart which shows the relationship of the operation timing of the image pickup element, the liquid crystal monitor, the image analysis circuit, and the piezoelectric element which concerns on Example 2 of this invention. It is a figure for demonstrating the sweep time of the frequency of the voltage applied to a piezoelectric element at the operation timing in FIG. It is a flowchart of the parallel execution processing of the LV display function and the dust removal function which concerns on Example 2 of this invention. It is a timing chart which shows the relationship of the operation timing of the image pickup element, the liquid crystal monitor, and the piezoelectric element which concerns on Example 3 of this invention. It is a figure for demonstrating the sweep time of the frequency of the voltage applied to a piezoelectric element at the operation timing in FIG. It is a flowchart of the parallel execution processing of the LV display function and the dust removal function which concerns on Example 3 of this invention.

(Example 1)
FIG. 1 is a block diagram showing a main electrical configuration of the image pickup apparatus 1 according to the present embodiment. Here, the image pickup device 1 in this embodiment is a digital camera, but may be a device having a vibration member for removing foreign matter from the optical member arranged on the subject side of the image pickup element. Specifically, it may be a camera unit such as a video camera or a smartphone.

The image pickup device 1 includes a mount contact 106, a shutter 107, a shutter drive circuit 108, an image pickup unit 109, a piezoelectric element drive circuit 114, an image pickup control circuit 118, a video signal processing circuit 119, an MPU 120, a liquid crystal drive circuit 123, and a power supply circuit 128. To be equipped. Here, the image pickup unit 109 is a component in which the infrared cut filter 110, the piezoelectric element 111, the optical low-pass filter 112, and the image pickup element 113 are unitized together with other components described later, although the details will be described later.

The photographing lens unit 2 that can be attached to and detached from the image pickup device 1 via the mount contact 106 includes a photographing lens 101, an aperture 102, an AF drive circuit 103, an aperture drive circuit 104, and a lens control circuit 105.

The MPU 120 is a central processing unit composed of a microcomputer built in the main body of the imaging device 1. The MPU 120 controls the entire operation of the image pickup apparatus 1, and executes various processes and instructions for each element.

A shutter drive circuit 108 and a video signal processing circuit 119 are connected to the MPU 120. The liquid crystal drive circuit 123, the power supply circuit 128, the piezoelectric element drive circuit 114, and the image pickup control circuit 118 are also connected to the MPU 120. These circuits operate under the control of the MPU 120.

Further, the MPU 120 communicates with the lens control circuit 105 arranged in the photographing lens unit 2 via the mount contact 106.

The mount contact 106 also has a function of transmitting a signal to the MPU 120 when the photographing lens unit 2 is connected.

As a result, the lens control circuit 105 can communicate with the MPU 120 and drive the photographing lens 101 and the aperture 102 in the photographing lens unit 2 via the AF drive circuit 103 and the aperture drive circuit 104. It becomes.

In the present embodiment, the photographing lens 101 is shown as one photographing lens for convenience, but it is actually composed of a large number of lens groups including a focus lens.

The AF drive circuit 103 is composed of a stepping motor, and is adjusted so that the subject is in focus by changing the position of the focus lens in the photographing lens 101 under the control of the lens control circuit 105.

The MPU 120 obtains the defocus amount and the defocus direction from the photographed luminous flux received by the image sensor 113.

Based on the obtained information, the focus lens in the photographing lens 101 is driven to the in-focus position via the lens control circuit 105 and the AF drive circuit 103.

The aperture drive circuit 104 is configured by, for example, an auto iris or the like, and the aperture 102 is changed by the lens control circuit 105 to obtain an optical aperture value.

The shutter 107 is a mechanical focal plane shutter, which is in an open state during live view (hereinafter referred to as LV) display, and guides a shooting light flux having a shooting optical axis 100 to the image pickup element 113. Further, at the time of imaging, a desired exposure time is obtained by the traveling time difference between the front blade group and the rear blade group (not shown) according to the release signal.

The shutter 107 is controlled by the shutter drive circuit 108 that receives the command of the MPU 120.

As the image sensor 113, CMOS, which is an image pickup device, is used in this embodiment. The image sensor 113 may be another image pickup device, for example, CCD, CID, etc., as long as it is an image pickup device composed of a plurality of pixels arranged in two dimensions capable of photoelectric conversion of the shooting luminous flux.

The image sensor 113 sequentially accumulates electric charges while shifting the time for each horizontal line, and reads them out as an image pickup signal.

The image pickup device 1 further includes a clamp / CDS (correlation double sampling) circuit 115, an AGC (automatic gain control device) 116, an A / D converter 117, a memory controller 121, a buffer memory 122, and a liquid crystal monitor (display unit) 124. , And a power supply unit 129. The memory 125 is a flash memory or the like that can be attached to and detached from the image pickup apparatus 1, and stores moving image / still image data.

The clamp / CDS circuit 115 performs basic analog processing before A / D conversion, and can also change the clamp level.

The AGC 116 performs basic analog processing before A / D conversion, and can also change the AGC basic level.

The A / D converter 117 digitizes the image pickup signal output from the image pickup device 113.

The infrared cut filter 110 is a rectangular filter that removes light having a high spatial frequency, specifically, a wavelength in the infrared region, from the shooting luminous flux, and is conductive on the surface in order to prevent foreign matter from adhering as described later. It is coated.

The optical low-pass filter 112 is formed by laminating a plurality of birefringent plates and phase plates made of quartz. The optical low-pass filter 112 separates the photographing light flux incident on the image pickup device 113 into a plurality of images, and effectively reduces the generation of false resolution signals and false color signals.

The piezoelectric element drive circuit 114 is a circuit that bends and vibrates the piezoelectric element 111 fixed to the infrared cut filter 110. The piezoelectric element drive circuit 114 vibrates the piezoelectric element 111 and generates an amplitude when the infrared cut filter 110 vibrates according to the instruction of the MPU 120.

In this embodiment, the optical member that excites bending vibration with the piezoelectric element 111 is an infrared cut filter 110, but any optical member that is inside the image pickup unit 109 and is arranged on the subject side of the image pickup element 113. Not limited to this. For example, the optical low-pass filter 112 formed by laminating a birefringent plate and a phase plate, or one of the birefringent plate or the phase plate constituting the optical low-pass filter 112 may be used as an optical member for exciting bending vibration with a piezoelectric element 111. Good.

The method of driving the piezoelectric element 111 will be described later.

The image pickup control circuit 118 controls the accumulation of electric charges and the reading of the image pickup signal of the image pickup element 113 according to the instructions of the MPU 120.

The video signal processing circuit 119 executes all hardware image processing such as gamma / knee processing, filter processing, and information synthesis processing for monitor display on the image pickup signal digitized by the A / D converter 117. As a result, in the video signal processing circuit 119, the moving image / still image data for monitor display displayed on the liquid crystal monitor 124 and the moving image / still image data stored in the memory 125 are generated and output.

The buffer memory 122 temporarily stores moving image / still image data for monitor display from the video signal processing circuit 119, and then outputs the data to the liquid crystal monitor 124 via the liquid crystal drive circuit 123.

The liquid crystal drive circuit 123 drives the liquid crystal monitor 124 according to the instructions of the MPU 120.

The LV display function is a function of performing the following operations in the image pickup apparatus 1. First, according to the instruction of the MPU 120, the imaging control circuit 118 sequentially photoelectrically converts the optical image of the subject to the imaging element 113 at time intervals according to the frame rate, continuously accumulates electric charges, and reads them out as an analog imaging signal. Control. Then, digital moving image data is generated from the continuously read imaging signals by the clamp / CDS circuit 115, AGC116, A / D converter 117, and video signal processing circuit 119, and is primarily stored in the buffer memory 122. Will be done. After that, the liquid crystal drive circuit 123 continuously displays the moving image data read from the buffer memory 122 as an LV image on the liquid crystal monitor 124 at an update interval according to the frame rate.

The video signal processing circuit 119 also has a function of performing image data compression processing such as JPEG.

When continuous shooting such as continuous shooting is performed, it is also possible to temporarily store the image data in the buffer memory 122 and sequentially read the unprocessed image data through the memory controller 121. As a result, the video signal processing circuit 119 can sequentially perform image processing and compression processing regardless of the speed of the image data input from the A / D converter 117.

The power supply circuit 128 supplies the MPU 120 with the necessary power according to various modes such as the cleaning mode, and also supplies the necessary power to each part of the image pickup apparatus 1 shown in FIG. 1 via the power supply unit 129.

Upon receiving the signal for starting the cleaning mode, the MPU 120 drives the shutter 107 to a position where it is retracted from the photographing luminous flux via the shutter drive circuit 108.

In this cleaning mode, the user can directly clean the foreign matter on the infrared cut filter 110 using a cotton swab, sylbon paper, rubber, or the like.

Further, the imaging device 1 includes a SW126 and a mode setting unit 127.

The mode setting unit 127 sets various modes such as a shooting mode and the cleaning mode in response to a user instruction from an operation unit (not shown).

The SW126 is a release switch, which receives a half-press operation by the user and transmits an AF instruction to the MPU 120, and receives a full-press operation by the user and transmits an instruction to start shooting to the MPU 120.

Next, the dust removal function in the image pickup apparatus 1 will be described.

When the execution of the dust removal function is started, the MPU 120 first instructs the piezoelectric element drive circuit 114 to apply a voltage of a predetermined frequency to the piezoelectric element 111 fixed to the infrared cut filter 110. When such a voltage is applied, the piezoelectric element 111 expands and contracts in a direction perpendicular to the optical axis, causing the infrared cut filter 110 to bend and vibrate. As a result, foreign matter on the infrared cut filter 110 is removed. Hereinafter, the expansion / contraction operation of the piezoelectric element 111 by applying such a voltage is referred to as a foreign matter removing operation.

The vibration efficiency can be improved by sweeping the frequency of the voltage applied to the piezoelectric element 111 in the vicinity of the resonance frequency of the intrinsic mode of the infrared cut filter 110.

However, as shown in FIG. 2B, if the foreign matter removal operation is performed while the image sensor 113 is reading the image pickup signal, noise is superimposed on the image pickup signal and the image quality of the LV image is deteriorated.

This is because the image pickup signal of the image pickup element 113 is read out and the voltage is applied to the piezoelectric element 111 at the same time.

This is because the high-voltage transformer noise generated by applying the voltage to the piezoelectric element 111 is superimposed on the signal of the image data passing through the video signal processing circuit 119 from the image pickup element 113.

In order to prevent the superposition of the above-mentioned high-voltage transformer noise, it is desirable to complete the foreign matter removing operation before the image pickup device 113 starts reading the image pickup signal, as shown in FIG. 2A.

However, in this case, as compared with the case of FIG. 2B, it takes time for the LV image to be transmitted to the liquid crystal monitor 124, and the LV display is delayed.

In particular, in the case of a mirrorless camera in which the image pickup device 1 has abolished the optical viewfinder, the LV display is delayed because the subject is confirmed by looking at the LV display and the focusing state is confirmed by half-pressing the SW126 before shooting. Then, you may miss a photo opportunity.

In order to avoid such a situation, it is necessary to suppress the deterioration of the image quality of the LV image without delaying the LV display, complete the foreign matter removing operation, and achieve both the LV display function and the dust removing function.

Here, in order to suppress the deterioration of the image quality of the LV image, it is necessary to apply the voltage to the piezoelectric element 111 while avoiding the timing of reading the image pickup signal by the image pickup element 113. On top of that, in order to suppress the time delay until the LV display is performed, it is necessary to complete the voltage application to the piezoelectric element 111 in a short time and to surely remove foreign substances such as dust.

Therefore, in this embodiment, the voltage is applied to the piezoelectric element 111 at a time other than the time when the image sensor 113 is reading the image pickup signal, that is, during the blanking period. Here, the blanking period refers to a period between the reading time of the image pickup signal by the image pickup device 113 for one frame and the reading time of the image pickup signal by the image pickup device 113 for the next one frame.

FIG. 3 is a timing chart showing the relationship between the operation timings of the image pickup element 113, the liquid crystal monitor 124, and the piezoelectric element 111 according to the present embodiment.

In FIG. 3, the vertical synchronization signals V0, V1, V2, and V3 are reference signals that serve as operation timings for charge accumulation by the image sensor 113 and reading of the image sensor.

In this embodiment, the image sensor 113 repeatedly executes the accumulation of electric charges and the reading of the image pickup signal at the timing corresponding to the frame rate (V cycle).

Further, the liquid crystal monitor 124 displays an LV image based on the image pickup signal read in each V cycle on the liquid crystal monitor 124 at an update interval corresponding to the frame rate.

Further, the piezoelectric element 111 performs a foreign matter removing operation during a blanking period, that is, a period other than the period of the dotted line portion in FIG. 3 (the period of reading the image pickup signal by the image pickup device 113). Specifically, in this embodiment, the piezoelectric element 111 performs a foreign matter removing operation during the charge accumulation period of the image pickup element 113. In this embodiment, there is no period during which the image sensor 113 is not operating between the end of reading the image pickup signal for one frame and the timing of the next vertical synchronization signal, but if it does exist, it does exist. , That period is also included in the blanking period.

That is, in this embodiment, the image sensor 113, the liquid crystal monitor 124, and the piezoelectric element 111 operate at the following timings.

The storages A, B, and C indicate the charge storage periods by the image sensor 113 that start at the timings of the vertical synchronization signals V0, V1, and V2, respectively. Further, the readings A, B, and C indicate the reading period of the image pickup signal by the image pickup device 113 that starts at the end of each of the storages A, B, and C.

The LV displays A, B, and C synchronize with the vertical synchronization signals V0, V1, and V2, and display a display period of the LV image continuously displayed on the liquid crystal monitor 124 by the liquid crystal monitor 124 at an update interval according to the frame rate. Shown.

Foreign matter removal 1, 2, and 3 indicate the execution period of the foreign matter removal operation executed by the piezoelectric element 111 during the period of accumulation A, B, and C.

As described above, as shown in FIG. 3, the periods of foreign matter removal 1, 2 and 3 in which the foreign matter removing operation is performed do not overlap with the periods of readings A, B and C in which the image pickup signal is read out by the image pickup device 113. That is, the high-voltage transformer noise generated by applying the voltage to the piezoelectric element 111 is not superimposed on the image pickup signal passing through the video signal processing circuit 119 from the image pickup element 113. Therefore, in this embodiment, it is possible to prevent the image quality of the LV image displayed during the periods of LV displays A, B, and C from being deteriorated by the high voltage transformer noise.

As described above, when the foreign matter removing operation is performed during the foreign matter removing operations 1, 2 and 3 shown in FIG. 3, it is possible to prevent the deterioration of the image quality of the LV image displayed during the periods of the LV displays A, B and C. However, the infrared cut filter 110 must be dust-removed by the foreign matter removing operation in a short period of the blanking period.

Therefore, in this embodiment, when the dust removing function is executed in parallel with the execution of the LV display function, the voltage level applied to the piezoelectric element 111 during the foreign matter removing operation is made higher than when the dust removing function is executed alone. By doing so, the amplitude (amplitude of the abdomen) when the piezoelectric element 111 vibrates becomes large, and it becomes easy to remove foreign matter such as dust on the infrared cut filter 110.

Further, the sweep time when the frequency of the voltage applied to the piezoelectric element 111 is swept from the high frequency side to the low frequency side during the foreign matter removing operation is changed. Specifically, as shown in FIG. 5, when the dust removal function is executed in parallel with the LV display function, the period ta in FIG. 4 is larger than that when the dust removal function is executed alone (thick line in FIG. 5). The sweep time at tb and tc is reduced (thin line in the figure).

Next, the procedure of parallel execution processing of the LV display function and the dust removal function in the image pickup apparatus 1 of this embodiment will be described with reference to the flowchart of FIG. This process is executed by the MPU 120.

First, when the power switch (not shown) of the imaging device 1 is turned on by the user and the power is turned on to the imaging device 1 (YES in step S600), the process proceeds to step S601.

In step 601 it is determined whether or not the driving of the image sensor 113 is started by the supply of electric power, that is, whether or not the operation of the LV display function is started. As a result of this determination, if the image sensor 113 has not been driven yet, the process proceeds to step S611, and if the image sensor 113 starts to be driven, the process proceeds to step S602.

In step S611, when a foreign matter removal instruction is given by the user (YES in step S611), when the mode setting unit 127 sets the cleaning mode in response to this instruction, the MPU 120 performs the dust removal function independently in step S612. move on. On the other hand, if there is no such instruction, the process returns to step S600. In this flowchart, the determination in step S611 is performed only before the start of the operation of the LV display function, but even after the start of the operation of the LV display function, if the user gives an instruction to remove foreign matter, , Step S612.

In step S612, the voltage level Vx applied to the piezoelectric element 111 is set with respect to the piezoelectric element drive circuit 114.

Next, in step S613, the sweep time tx when the frequency of the voltage applied to the piezoelectric element 111 is swept from the high frequency side to the low frequency side is set for the piezoelectric element drive circuit 114.

Next, in step S605, the piezoelectric element drive circuit 114 is instructed to apply a voltage to the piezoelectric element 111 at the voltage level set in step S612 and the sweep time set in step S613, and the foreign matter removing operation is started. To do.

After that, when the foreign matter removing operation is completed (YES in step S606), the process shifts to the shooting standby state waiting for the user's shooting instruction, and this process ends (step S607).

On the other hand, when the power of the image pickup apparatus 1 is not turned on (NO in step S600), the MPU 120 proceeds to step S614 in order to execute the dust removal function independently. Here, when the power of the imaging device 1 is not turned on, there is a user operation to turn off the power SW, and when the power to the imaging device 1 is cut off, or when the power SW is turned on by the user. Refers to the case before the power is turned on to the image pickup apparatus 1.

In step S614, the voltage level Vx applied to the piezoelectric element 111 is set with respect to the piezoelectric element drive circuit 114.

Next, in step S615, the sweep time tx when the frequency of the voltage applied to the piezoelectric element 111 is swept from the high frequency side to the low frequency side is set for the piezoelectric element drive circuit 114.

Next, in step S616, the piezoelectric element drive circuit 114 is instructed to apply a voltage to the piezoelectric element 111 at the voltage level set in step S614 and the sweep time set in step S615, and the foreign matter removing operation is started. To do.

After that, when the foreign matter removing operation is completed (YES in step S617), the process returns to step S600 and waits for the power of the image pickup apparatus 1 to be turned on.

Further, when the driving of the image sensor 113 is started (YES in step S601) after the power-on of the image sensor 1 is completed in step S600 (YES in step S600), it is determined whether or not it is the blanking period (step S601). S602). When it is determined that it is not the blanking period (NO in step S602), the image sensor 113 reads out the image pickup signal (step S608). After that, the video signal processing circuit 119 generates digitized moving image data that has undergone various image processing and is displayed on the liquid crystal monitor 124 as an LV image from the read image pickup signal (step S609). ). After that, when the generated moving image data is displayed as an LV image on the liquid crystal monitor 124 via the liquid crystal drive circuit 123 (step S610), the process shifts to the shooting standby state and the present process ends (step S607).

On the other hand, when it is determined that the blanking period is reached (YES in step S602), the voltage level Vy applied to the piezoelectric element 111 in step S603 is set with respect to the piezoelectric element drive circuit 114. The voltage level Vy set here is larger than the voltage level Vx set in steps S612 and S614. That is, the voltage level applied to the piezoelectric element 111 is set so that Vy> Vx.

Next, in step S604, the sweep time ty for sweeping the frequency of the voltage applied to the piezoelectric element 111 set in step S613 or step S615 from the high frequency side to the low frequency side is set. The sweep time ty set here is smaller than the sweep time tx set in steps S613 and S615. That is, it is set so that tx> ty.

Next, in step S605, the piezoelectric element drive circuit 114 is instructed to apply a voltage to the piezoelectric element 111 at the voltage level set in step S603 and the sweep time set in step S604, and the foreign matter removing operation is started. To do.

After that, when the foreign matter removing operation is completed (YES in step S606), the state shifts to the shooting standby state, and this process ends (step S607). The completion of the foreign matter removing operation here is when the SW126 user has half-pressed or fully-pressed. That is, as shown in FIG. 3, the foreign matter removing operation during the blanking period is repeatedly executed until the SW126 user performs a half-press or full-press operation.

As described above, in this embodiment, while the image pickup device 113 is being driven, the voltage level applied to the piezoelectric element 111 during the blanking period is increased, and the sweep time of the voltage applied to the piezoelectric element 111 is shortened. As a result, there is no delay in the LV display after the power switch is turned on, the deterioration of the image quality of the LV image is prevented, and the infrared cut filter 110 is efficiently used within the limited time of the blanking period. Foreign matter such as dust on the top can be removed.

(Example 2)
Next, the parallel execution processing of the LV display function and the dust removal function in the image pickup apparatus 1a according to the second embodiment will be described with reference to FIGS. 7 to 10.

FIG. 7 is a block diagram showing a main electrical configuration of the image pickup apparatus 1a according to the present embodiment.

The image pickup device 1a of this embodiment is different from the image pickup device 1 of Example 1 in that it has an image analysis circuit 700. The configurations common to the block diagram of FIG. 1 described above are indicated by the same numbering, and duplicate description will be omitted.

In FIG. 7, the image analysis circuit 700 detects the position of foreign matter such as dust present on the infrared cut filter 110 reflected in the LV image displayed on the liquid crystal monitor 124. Specifically, the image analysis circuit 700 is based on the moving image data generated from the imaging signal during the operation of the LV display function, and the position information of the foreign matter on the infrared cut filter 110 in the two-dimensional coordinates of the x coordinate and the y coordinate. Is acquired, and the position information is supplied to the MPU 120.

The MPU 120 changes the parameters of the piezoelectric element drive circuit 114 during the foreign matter removing operation based on the supplied position information.

FIG. 8 is a timing chart showing the relationship between the operation timings of the image sensor 113, the liquid crystal monitor 124, the image analysis circuit 700, and the piezoelectric element 111 according to the present embodiment.

As shown in FIG. 8, the timing at which the image analysis circuit 700 starts the foreign matter position detection A, B, C for performing the foreign matter position detection operation is set at the same timing as the start of the LV displays A, B, C.

During the period of foreign matter position detection A, the image analysis circuit 700 acquires the position information of the foreign matter from the moving image data displayed as the LV image during the period of LV display A, and supplies the position information to the MPU 120.

Based on the supplied position information, the MPU 120 changes the parameters at the time of the foreign matter removing operation set for the piezoelectric element drive circuit 114 during the period of the foreign matter removing 3 which starts in synchronization with the next vertical synchronization signal V2.

Similarly, during the period of foreign matter position detection B, the image analysis circuit 700 acquires the position information of the foreign matter from the moving image data displayed as the LV image during the period of LV display B, and supplies the position information to the MPU 120.

The MPU 120 is a parameter during the foreign matter removal operation set for the piezoelectric element drive circuit 114 during the foreign matter removal 4 (not shown) period which starts in synchronization with the next vertical synchronization signal V3 based on the supplied position information. To change.

For example, as shown in FIG. 9, during the periods of foreign matter removal 1 and 2 (ta, tb period), the frequency of the voltage applied to the piezoelectric element 111 is swept at the same sweep time as the sweep time of the thin wire shown in FIG. Performs foreign matter removal operation. On the other hand, the position of the foreign matter such as dust existing in the moving image data displayed as the LV image during the period of the LV display A in parallel with the foreign matter removing operation in the tb period is detected by the image analysis circuit 700 of the foreign matter position detection A. Detect during the period.

Here, consider a case where the frequency of the voltage at which the foreign matter detected during the foreign matter position detection A period by the image analysis circuit 700 can be removed most efficiently is the frequency f1 swept during the tb period. Further, the execution periods of the foreign matter removing operation in the vertical synchronization signal V3 and the next vertical synchronization signal V4 are defined as periods td and te, respectively.

In this case, the MPU 120 is changed so that the frequency of the voltage applied to the piezoelectric element 111 after the next foreign matter removal 2 period (period ct) is swept with a sweep time different from that of FIG. 5 as shown in FIG. Specifically, a voltage having a constant frequency f1 is applied to the piezoelectric element 111 in the next period ct of the tb period including the frequency f1 and the next period td. After the subsequent period te, the frequency of the voltage of the piezoelectric element 111 is sequentially swept from the frequency f1 to the lower frequency side in the same sweep time as the sweep time shown by the thin line in FIG.

That is, in this embodiment, the image analysis circuit 700 detects the position of foreign matter such as dust on the infrared cut filter 110 reflected in the LV image, and the effect of removing the foreign matter at the detected position is the highest. Set the parameters to be higher.

Next, the procedure of parallel execution processing of the LV display function and the dust removal function in the image pickup apparatus 1a of this embodiment will be described with reference to the flowchart of FIG. This process is executed by the MPU 120. In this process, the same steps as in FIG. 6 are designated by the same reference numerals, and duplicate description will be omitted. Further, since the steps S600, S601, and S611 to S617 are the same as those in FIG. 6, the description of these steps will be omitted and will not be shown in FIG.

After the driving of the image sensor 113 is started (YES in step S601), when it is determined that the blanking period is not reached (NO in step S602), the image sensor 113 reads out the image pickup signal (step S608). After that, the video signal processing circuit 119 generates digitized moving image data that has undergone various image processing and is displayed on the liquid crystal monitor 124 as an LV image from the read image pickup signal (step S609). ). After that, when the generated moving image data is displayed as an LV image on the liquid crystal monitor 124 via the liquid crystal drive circuit 123 (step S610), the process shifts to the shooting standby state and the present process ends (step S607). At this time, in parallel, the moving image data generated in step S609 is directly supplied from the video signal processing circuit 119 to the image analysis circuit 700, and the image analysis circuit 700 detects the position of foreign matter such as dust in the LV image. (Step S1001), and the process proceeds to step S1002. On the other hand, even if it is determined that the blanking period (YES in step S602), the process proceeds to step S1002.

In step S1002, the parameters of the piezoelectric element drive circuit 114 during the foreign matter removing operation are changed based on the foreign matter position detection result in step S1001. The parameter changed in step S1002 is the frequency of the voltage applied to the piezoelectric element 111, or the sweep time in each frequency band when the frequency of the applied voltage is swept from the high frequency side to the low frequency side. is there.

After that, the foreign matter removing operation is executed in step S605. Specifically, the foreign matter removing operation of the period tk in FIG. 6 is executed with the parameters changed based on the foreign matter position detection result in the foreign matter position detection A period. On the other hand, the foreign matter removing operations of the periods ta and tb in FIG. 6 are executed with the parameters set in steps S603 and S604 as in the first embodiment because the foreign matter position is detected by the image analysis circuit 700 before or at the same time. To.

Although not shown in FIG. 10, when the foreign matter removing operation started in step S605 is interrupted due to the end of the blanking period until the foreign matter removing operation is completed (YES in step S606), step S602 Return to.

Further, even if the foreign matter removing operation in step S605 is executed with the parameter related to the sweep time changed in step S1002, the position of the foreign matter such as dust detected in step S1001 may not change. In this case, in step S1002 executed at the next timing, the parameter may be changed so as to raise the level of the voltage applied to the piezoelectric element 111.

Further, in step S1001, a plurality of positions of foreign matter such as dust may be detected, that is, a plurality of foreign matter may be attached on the infrared cut filter 110. In this case, among the foreign matter reflected in the LV image, the parameter is changed in step S1002 so that the foreign matter located closer to the subject in the LV image is preferentially removed. Further, in this case, among the foreign matter reflected in the LV image, the parameter is changed in step S1002 so that the foreign matter located closer to the in-focus position in the LV image is preferentially removed.

As described above, in this embodiment, the position information of foreign matter such as dust is detected from the moving image data displayed on the liquid crystal monitor 124 as an LV image, and the parameter for driving the piezoelectric element 111 during the blanking period based on the detection result. To change. As a result, it is possible to reliably and quickly remove dust by the dust removing function while ensuring the image quality of the LV image without causing a delay in the LV display.

(Example 3)
Next, the parallel execution processing of the LV display function and the dust removal function in the image pickup apparatus 1 according to the third embodiment will be described with reference to FIGS. 11 to 13. In addition, this embodiment is executed by the image pickup apparatus 1 shown in FIG.

As shown in FIGS. 11 and 12, in the present embodiment, after the power SW of the image sensor 1 is turned on and the period t0 elapses after the power is turned on to the image sensor 1, the image sensor 113 is passed through the power supply unit 129. Power supply to is started. Further, at the same time as the start of power supply to the image pickup device 113, the charge accumulation and the reading of the image pickup signal by the image pickup device 113 according to the frame rate (V cycle) start.

Therefore, in this embodiment, the parameters for driving the piezoelectric element 111 in the period t0 and the piezoelectric element in the blanking period (period ta, tb) after the period t0 elapses and the power supply to the image sensor 113 starts. The parameters for driving the 111 are changed.

Specifically, the frequency of the voltage applied to the piezoelectric element 111 in the period t0 is set so that the abdomen of the vibration of the piezoelectric element 111 becomes coarser than in the cases of the periods ta and tb. As a result, foreign matter such as dust can be evenly removed from the entire infrared cut filter 110 during the period t0.

Further, as shown in FIG. 12, when the frequency of the voltage applied to the piezoelectric element 111 is swept from the high frequency side to the low frequency side, the difference in frequency between the steps in the period t0 is the difference in the periods ta and tb. Set to be larger.

If the time from turning on the power to the image sensor 1 to starting supplying power to the image sensor 113 is short (if the period t0 is short), the frequency sweep shown in FIG. 12 (2) does not have to be executed.

On the other hand, the parameter is set so that the voltage level in the periods ta and tb is larger than the level of the voltage applied to the piezoelectric element 111 set in the period t0. Further, the sweep time when the frequency of the voltage applied to the piezoelectric element 111 in the periods ta and tb is swept from the high frequency side to the low frequency side is set shorter than in the case of the period t0. As a result, even if the dust removal function is executed only during the blanking period after the start of power supply to the image sensor 113, the foreign matter removal operation can be efficiently completed in a short time.

Next, the procedure of parallel execution processing of the LV display function and the dust removal function in the image pickup apparatus 1 of this embodiment will be described with reference to the flowchart of FIG. This process is executed by the MPU 120. In this process, the same steps as in FIG. 6 are designated by the same reference numerals, and duplicate description will be omitted.

First, it is determined whether or not the power supply SW (not shown) of the image sensor 1 is turned on by the user, the power is turned on to the image sensor 1 (YES in step S1300), and then the power supply to the image sensor 113 is started. (Step S1301).

As a result of this determination, when the power supply to the image pickup element 113 is not started (NO in step S1301), the voltage level Vx applied to the piezoelectric element 111 is set for the piezoelectric element drive circuit 114 (step S1312). Further, in step S1313, the sweep time tx when the frequency of the voltage applied to the piezoelectric element 111 is swept from the high frequency side to the low frequency side is set with respect to the piezoelectric element drive circuit 114.

Next, in step S1314, the piezoelectric element drive circuit 114 is instructed to apply a voltage to the piezoelectric element 111 at the voltage level set in step S1312 and the sweep time set in step S1313, and the foreign matter removing operation is started. To do.

After that, when the foreign matter removing operation is completed (YES in step S1315), the process returns to step S1301 and waits for the power supply to the image sensor 113 to start.

On the other hand, when the power supply to the image sensor 113 is started (YES in step S1301) and the driving of the image sensor 113 is started (step S1302), it is determined whether or not it is the blanking period (step S602). When it is determined that it is not the blanking period (NO in step S602), the image sensor 113 reads out the image pickup signal (step S608). After that, the video signal processing circuit 119 generates digitized moving image data that has undergone various image processing and is displayed on the liquid crystal monitor 124 as an LV image from the read image pickup signal (step S609). ). After that, when the generated moving image data is displayed as an LV image on the liquid crystal monitor 124 via the liquid crystal drive circuit 123 (step S610), the process shifts to the shooting standby state and the present process ends (step S607).

On the other hand, when it is determined that the blanking period is reached (YES in step S1303), the voltage level Vy applied to the piezoelectric element 111 in step S1304 is set for the piezoelectric element drive circuit 114. The voltage level Vy set here is larger than the voltage level Vx set in step S1312. That is, it is set so that Vy> Vx.

Further, in step S1305, the sweep time ty for sweeping the frequency of the voltage applied to the piezoelectric element 111 from the high frequency side to the low frequency side is set. The sweep time ty set here is set to be smaller than the sweep time tx set in step S1313, that is, tx> ty.

Next, in step S605, the piezoelectric element drive circuit 114 is instructed to apply a voltage to the piezoelectric element 111 at the voltage level set in step S1312 and the sweep time set in step S1313, and the foreign matter removing operation is started. To do.

After that, when the foreign matter removing operation is completed (YES in step S606), the state shifts to the shooting standby state, and this process ends (step S607). The completion of the foreign matter removing operation here is when the SW126 user has half-pressed the operation. That is, as shown in FIG. 11, the foreign matter removing operation in the blanking period in each V cycle is repeatedly executed until the SW126 is half-pressed by the user.

As described above, in this embodiment, the foreign matter removing operation in the period t0 from the power-on of the image pickup device 1 to the start of the power supply to the image pickup device 113 is the piezoelectric element as compared with the case of the blanking period (period ta, tb). The parameters are set so that the abdomen of the vibration caused by 111 becomes rough.

Further, the parameters for the periods ta and tb, which are the blanking periods, increase the level of the voltage applied to the piezoelectric element 111 and shorten the sweep time of the frequency of the voltage applied to the piezoelectric element 111 as compared with the case of the period t0. To set.

This makes it possible to suppress the deterioration of the image quality of the LV image without causing a delay in the LV display, and to efficiently remove foreign substances such as dust within the limited time of the blanking period. Further, since the level of the voltage applied to the piezoelectric element 111 is appropriately switched, it is possible to suppress the consumption of a battery (not shown) in the power supply circuit 128.

As in the second embodiment, the information of the LV image may be used when setting the various parameters.

[Other Examples]
Needless to say, the object of the present invention is also achieved by supplying the device with a storage medium in which the program code of the software that realizes the functions of the above-described embodiment is recorded. At this time, the computer (or CPU or MPU) including the control unit of the supplied device reads and executes the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the program code itself and the storage medium storing the program code constitute the present invention.

As the storage medium for supplying the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory card, a ROM, or the like can be used.

Further, based on the instruction of the above-mentioned program code, the OS (basic system or operating system) running on the device performs a part or all of the processing, and the processing realizes the function of the above-described embodiment. It goes without saying that cases are also included.

Further, the program code read from the storage medium may be written in the memory provided in the function expansion board inserted in the device or the function expansion unit connected to the computer to realize the functions of the above-described embodiment. Needless to say, it is included. At this time, based on the instruction of the program code, the function expansion board, the CPU provided in the function expansion unit, or the like performs a part or all of the actual processing.

1,1a Imaging device 110 Infrared cut filter (optical member)
111 Piezoelectric element 113 Image sensor 114 Piezoelectric element drive circuit 118 Image control circuit 119 Video signal processing circuit 120 MPU
124 LCD monitor 700 Image analysis circuit

Claims (14)

An imaging element that photoelectrically converts the optical image of the subject, accumulates electric charge, and reads it out as an imaging signal.
An optical member arranged on the subject side of the image sensor and
A piezoelectric element that is fixed to the optical member and expands and contracts when a voltage is applied.
Display means and
The drive of the image sensor and the display means is controlled, the image sensor is sequentially read from the image sensor at a time interval according to the frame rate, and the image sensor is continuously live at an update interval according to the frame rate based on the image sensor. A first control means for executing a live view display function for displaying a view image by the display means, and
An imaging device including a second control means that controls the application of a voltage to the piezoelectric element, vibrates the optical member by expanding and contracting the piezoelectric element, and executes a dust removing function for removing dust from the optical member. There,
In the first case where the second control means executes the dust removal function in parallel with the execution of the live view display function by the first control means, the piezoelectric element is used during the blanking period while the image pickup device is being driven. An image pickup device characterized in that a voltage is applied to the image sensor. The image pickup apparatus according to claim 1, wherein the blanking period includes a period in which the charge is accumulated by the image pickup device. The second control means sets the parameters for controlling the application of the voltage to the piezoelectric element in the second case of performing dust removal of the optical member according to the instruction of the user, and the power supply to the image pickup apparatus. The imaging device according to claim 1 or 2, wherein the third case in which dust removal of the optical member is performed before being charged is different from the first case. The second control means is characterized in that the parameter is set so that the amplitude when the optical member is vibrated in the first case is larger than that in the second and third cases. 3. The imaging device according to 3. The second control means sets the parameter so that the sweep time when sweeping the frequency of the voltage applied to the piezoelectric element in the first case is shorter than that in the second and third cases. The imaging device according to claim 3 or 4, wherein the image pickup apparatus is characterized by the above. A detection means for detecting the position of a foreign substance adhering to the optical member based on the image pickup signal read from the image pickup element is further provided.
The second control means is any one of claims 1 to 5, wherein the second control means controls the vibration of the optical member by the piezoelectric element based on the position of the foreign matter detected by the detection means. The imaging apparatus according to. When it is detected by the detection means that a plurality of foreign substances are attached to the optical member, the vibration of the optical member by the piezoelectric element is controlled according to the position of each of the plurality of foreign substances in the optical member. 6. The imaging device according to claim 6. 6 or 7 according to claim 6, wherein the vibration of the optical member by the piezoelectric element is controlled based on the position of the foreign matter detected by the detection means in the optical member and the in-focus position in the live view image. The imaging device described. The second control means sets the parameters for controlling the application of the voltage to the piezoelectric element to the optics between the time when the power is turned on to the image sensor and the time when the power supply to the image sensor is started. The image pickup apparatus according to any one of claims 1 to 8, wherein the fourth case of performing dust removal of the member and the first case are different from each other. 9. The second control means is characterized in that the parameter is set so that the abdomen of vibration when the optical member is vibrated in the fourth case is coarser than that in the first case. The imaging apparatus described. The second control means 9 or 10 is characterized in that the parameter is set so that the amplitude when the optical member is vibrated in the first case is larger than that in the fourth case. The imaging device described. The second control means is characterized in that the parameter is set so that the sweep time when sweeping the frequency of the voltage applied to the piezoelectric element in the first case is shorter than that in the fourth case. The imaging device according to any one of claims 9 to 10. An image pickup element that photoelectrically converts an optical image of a subject to accumulate electric charge and reads it out as an image pickup signal, an optical member arranged on the subject side of the image pickup element, and a piezoelectric material that is fixed to the optical member and expands and contracts when a voltage is applied. A control method for an image pickup device including an element and a display unit.
The drive of the image sensor and the display unit is controlled, the image sensor is sequentially read from the image sensor at a time interval according to the frame rate, and the image sensor is continuously live at an update interval according to the frame rate based on the image sensor. The first control step of executing the live view display function of displaying the view image on the display unit, and
It has a second control step of controlling the application of a voltage to the piezoelectric element, vibrating the optical member by expanding and contracting the piezoelectric element, and executing a dust removing function for removing dust from the optical member.
When the dust removal function is executed in parallel with the execution of the live view display function in the first control step, the second control step is a voltage to the piezoelectric element during a blanking period while the image sensor is being driven. A control method characterized in that application is performed. A program comprising executing the control method according to claim 13.

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