JP2013025150A - Imaging device, foreign material removal method and foreign material removal program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain performance of sufficiently removing a foreign material.SOLUTION: An imaging device comprises: an imaging element for photoelectrically converting subject light; an optical member that is arranged in front of the imaging element; excitation means for vibrating the optical member; estimation means for using a first oscillation frequency for oscillating the optical member to estimate an estimated frequency to be presumed to oscillate the optical member, except for the first oscillation frequency; control means for controlling the excitation means so as to vibrate the optical member by applying multiple changes to a frequency within a range of frequency bandwidth including the estimated frequency; identification means for identifying a second oscillation frequency for oscillating the optical member, on the basis of a vibration state of the optical member when vibrating the optical member by applying multiple changes to the frequency within the range of frequency bandwidth including the estimated frequency; and storage means for storing the second oscillation frequency.

Description

  The present invention relates to an imaging apparatus, a foreign matter removal method, and a foreign matter removal program that vibrate an optical member disposed in front of an imaging element to remove foreign matter attached to the surface thereof.

  An imaging apparatus represented by a digital camera includes an imaging optical system and an imaging element. An optical member such as dust-proof glass for preventing dust from adhering to the front surface of the image sensor is disposed in front of the image sensor. In such an imaging apparatus, for example, a technique has been proposed in which an optical member is vibrated in a frequency band including a resonance frequency to remove foreign matters such as dust attached to the surface of the optical member (see Patent Document 1). In this case, the optical member is vibrated with a certain frequency width relative to the resonance frequency so that the foreign substance removal performance does not deteriorate even when the resonance frequency changes due to variations in the optical member, aging, ambient temperature, etc. I try to let them.

JP 2009-188949 A

  In this case, since the optical member is vibrated while being shifted by a predetermined frequency within the set frequency band, when the time for vibrating the optical member at the same frequency is constant, the optical member is applied to the entire frequency band. There is a problem that the total time to vibrate becomes longer. On the other hand, when the total time for vibrating the optical member over the entire frequency band is set to a fixed time, the time for vibrating the optical member at each frequency is shortened, and sufficient foreign matter removal performance cannot be obtained. It is also conceivable to secure time for vibrating the optical member at each frequency by setting a large frequency to be changed (shifted) within a set frequency band. However, when the frequency shifted within the set frequency band is set to be large, the optical member may not be vibrated at the resonance frequency, and as a result, sufficient foreign matter removal performance cannot be obtained.

  An object of the present invention is to provide an imaging device, a foreign matter removal method, and a foreign matter removal program that can obtain sufficient foreign matter removal performance.

  In order to solve the above-described problem, an imaging apparatus of the present invention includes an imaging element that photoelectrically converts subject light, an optical member that is disposed in front of the imaging element, and a vibration unit that vibrates the optical member, Estimating means for obtaining an estimated frequency estimated to resonate the optical member using a first resonance frequency at which the optical member resonates, other than the first resonance frequency; and within a frequency band including the estimated frequency And a control means for controlling the excitation means to vibrate the optical member by changing the frequency a plurality of times, and the optical member by changing the frequency a plurality of times within a frequency band including the estimated frequency. Based on the vibration state of the optical member when vibrated, a specifying means for specifying a second resonance frequency at which the optical member resonates and a storage means for storing the second resonance frequency are provided. Characterized in that was.

  In addition, the specifying unit is configured to have a maximum amplitude amount among amplitude amounts obtained when the optical member is vibrated while changing the frequency a plurality of times within a frequency band including the estimated frequency. Preferably, the frequency is specified as the second resonance frequency.

  Moreover, it is preferable that the estimation means estimates the other resonance frequency by multiplying the first resonance frequency by a coefficient.

  In this case, it is preferable that the estimation unit holds the coefficient when the specified second resonance frequency matches the other resonance frequency.

  Further, the estimation means replaces the coefficient with a value obtained from the first resonance frequency and the second resonance frequency when the specified second resonance frequency does not match the estimated frequency. Is preferred.

  Further, the control means controls the excitation means to vibrate the optical member by changing the frequency a plurality of times within a preset frequency band, and the specifying means is preset. It is preferable to specify the first resonance frequency based on a vibration state of the optical member when the frequency is changed a plurality of times within a frequency band.

  Further, the control means includes a first vibration operation that vibrates the optical member while changing the frequency a plurality of times within a range of a frequency band including the first resonance frequency, and the second resonance frequency. It is preferable to control the excitation means so as to execute a second vibration operation that vibrates the optical member while changing the frequency a plurality of times within a frequency band.

  Further, the foreign matter removing method of the present invention is an imaging apparatus comprising: an imaging element that photoelectrically converts subject light; an optical member that is disposed in front of the imaging element; and a vibration unit that vibrates the optical member. In the foreign matter removing method, using the first resonance frequency when the optical member resonates, an estimation process for obtaining an estimated frequency estimated to resonate the optical member other than the first resonance frequency, and the estimated frequency A control process for controlling the excitation means so as to vibrate the optical member by changing the frequency a plurality of times within a frequency band including the frequency band, and a plurality of times the frequency within the frequency band including the estimated frequency. A specifying process for specifying a second resonance frequency at which the optical member resonates based on a vibration state of the optical member when the optical member is vibrated by being changed, and the second resonance And having a storage process of storing the wavenumber, a.

  The foreign matter removal program according to the present invention includes an imaging device including an imaging device that photoelectrically converts subject light, an optical member that is disposed in front of the imaging device, and a vibration unit that vibrates the optical member. In the foreign matter removal program for controlling, an estimation process for obtaining an estimated frequency other than the first resonance frequency by using the first resonance frequency when the optical member resonates, and estimating the estimated resonance frequency of the optical member; A control process for controlling the excitation means so as to vibrate the optical member by changing the frequency a plurality of times within a range of the frequency band including the estimated frequency, and within the range of the frequency band including the estimated frequency. A specifying process for specifying a second resonance frequency at which the optical member resonates based on a vibration state of the optical member when the optical member is vibrated by changing the frequency a plurality of times. When a storage process of storing the second resonant frequency, those capable of causing a computer to execute the.

  According to the present invention, sufficient foreign matter removal performance can be obtained.

It is a figure which shows the structure of a digital camera. It is a perspective view which decomposes | disassembles and shows the structure of an imaging unit. It is a figure which shows the relationship between the frequency and amplitude which are vibrated by dustproof glass. 3 is a flowchart showing a flow of a first vibration operation. It is a flowchart which shows the flow of 2nd vibration operation | movement. It is a graph which shows an example of the secular change of the coefficient k.

  FIG. 1 is a diagram illustrating a schematic configuration of a digital camera 10 as an example of an imaging apparatus.

  As shown in FIG. 1, the digital camera 10 includes an imaging optical system 15, an imaging unit 16, an A / D converter 17, a piezoelectric element driving circuit 18, a buffer memory 20, an image processing circuit 21, a connection I / F 22, a display. A control circuit 23, a display device 24, a release button 26, an operation unit 27, a CPU 30, a built-in memory 31, and the like are provided. Among these, the A / D converter 17, the buffer memory 20, the image processing circuit 21, the connection I / F 22, the display control circuit 23, the CPU 30, and the built-in memory 31 are electrically connected via a bus 33. The digital camera 10 is loaded with a storage medium 34. When the storage medium 34 is attached to the digital camera 10, the storage medium 34 and the connection I / F 22 are electrically connected.

  The imaging optical system 15 includes a plurality of lenses. In FIG. 1, it is shown as a single lens for convenience. Each lens of the imaging optical system 15 moves in the optical axis (L) direction when the zoom magnification is changed. The imaging optical system 15 includes a focus adjustment lens, and the focus adjustment lens slightly moves in the optical axis (L) direction during focus adjustment.

  The imaging unit 16 includes an imaging element 36, a dustproof glass 37, and a piezoelectric element 38. As the image sensor 36, for example, a CCD image sensor or a CMOS image sensor is used. The image sensor 36 includes a plurality of pixels. The imaging device 36 receives the subject light (incident light) taken in by the imaging optical system 15 at each pixel and converts it into signal charges. A voltage based on this signal charge is output as a pixel signal of each pixel. A signal obtained by combining pixel signals of a plurality of pixels into one becomes an image signal. This image signal is input to the A / D converter 17 after being subjected to processing such as clamping processing and correlated double sampling (CDS) processing.

  The dust-proof glass 37 is disposed in the vicinity of the image sensor 36 between the image pickup optical system 15 and the image sensor 36. The image sensor 36 is protected by the dust-proof glass 37.

  The piezoelectric element 38 is provided on the periphery of the dust-proof glass 37 (see FIG. 2). The piezoelectric element 38 vibrates the dust-proof glass 37 at a preset frequency when driven. The piezoelectric element 38 detects the vibration state of the dust-proof glass 37 when driven. This detection signal is output to the CPU 30. The CPU 30 calculates the amplitude amount of the dust-proof glass 37 that vibrates by the piezoelectric element 38 from the detection signal output from the piezoelectric element 38.

  The A / D converter 17 converts the image signal output from the image sensor 36 from an analog signal to a digital signal. This digitized image signal is written into the buffer memory 20.

  The piezoelectric element driving circuit 18 controls driving of the piezoelectric element 38. The piezoelectric element drive circuit 18 is configured to be able to arbitrarily change the frequency when the piezoelectric element 38 vibrates the dustproof glass 37.

  The buffer memory 20 is composed of a non-volatile flash memory or the like, and temporarily stores image signals output from the A / D converter 17 and image data subjected to various image processes by the image processing circuit 21.

  The image processing circuit 21 performs image processing such as white balance processing, color interpolation processing, contour compensation processing, and gamma processing on the image signal written in the buffer memory 20. Thereby, still image data and moving image data are generated. The generated still image data and moving image data are temporarily stored in the buffer memory 20.

  The connection I / F 22 can electrically write data to the storage medium 34 and read data stored in the storage medium 34 by being electrically connected to the storage medium attached to the digital camera. It becomes. Examples of the storage medium 34 include a memory card and an optical disk.

  The display device 24 includes, for example, an LCD panel or an EL display panel. The display device 24 displays a setting image used for setting in addition to a through image and an image obtained by photographing. The image display on the display device 24 is controlled by the display control circuit 23.

  The release button 26 is a member operated when performing still image shooting or moving image shooting. The operation unit 27 is operated when performing basic setting, setting at the time of shooting (setting of shooting mode and shooting conditions), and setting of image display in the digital camera 10.

  The CPU 30 controls each part of the digital camera 10 by reading and executing a control program stored in the built-in memory 31. The CPU 30 executes an imaging process based on the operation of the release button 26 described above and a process based on the operation of the operation unit 27. Examples of the processing based on the operation of the operation unit 27 include processing represented by date setting of the digital camera 10 and setting of shooting conditions at the time of shooting.

  FIG. 2 shows an exploded configuration of the imaging unit 16. The imaging unit 16 includes an imaging element 36, a dustproof glass 37, a piezoelectric element 38, a cover 40, a mask member 41, and a circuit board 42. The imaging unit 16 locks the cover 40 to the circuit board 42 with screws or the like in a state where the mask member 41, the dust-proof glass 37, and the cover 40 are laminated in this order on the circuit board 42 to which the imaging element 36 is attached. Formed with. The opening 40a provided in the cover 40 shields the light beam incident from a place other than the opening 40a, and projects the light beam incident through the opening 40a toward the image sensor 36. it can. With this configuration, the photographing light flux is prevented from entering the image pickup device 36 from the outer peripheral portion of the image pickup unit 16, and the occurrence of ghost due to reflected light is prevented.

  Next, the foreign substance removal process will be described. As shown in FIG. 3A, in the foreign matter removal process of the present invention, the first vibration operation that changes by the change amount Δf within the first frequency band is different from the first vibration operation. A second oscillating operation that changes by the change amount Δf within the frequency band of 2 is executed.

  First, the first vibration operation in the foreign matter removal process will be described based on the flowchart shown in FIG. Hereinafter, the lower limit value of the first frequency band used in the first vibration operation is the frequency fs1, and the upper limit value is the frequency fe1. In addition, this 1st frequency band is a frequency band containing the resonant frequency (1st resonant frequency F1) with which the dust-proof glass 37 resonates. Here, the lower limit value fs1 and the upper limit value fe2 of the first frequency band are values obtained by experiments, inspections, and the like, and are values that consider variations in the first resonance frequency F1, and these values are the first value. The value is set in a range of ± 5 to ± 10% of the resonance frequency F1.

  FIG. 4 is a flowchart showing a flow of processing when performing the first vibration operation in the foreign matter removal processing.

  Step S101 is a process of reading the lower limit value fs1 and the upper limit value fe1 of the first frequency band. The CPU 30 reads the lower limit value fs1 and the upper limit value fe1 of the first frequency band stored in the built-in memory 31.

  Step S102 is a process of setting the frequency f for vibrating the dust-proof glass 37 to the lower limit value fs1 (f = fs1). The process of step S102 is executed by the CPU 30.

  Step S103 is processing to vibrate the dustproof glass at the set frequency f. The CPU 30 outputs information on the set frequency f to the piezoelectric element driving circuit 18. In response to this, the piezoelectric element driving circuit 18 drives the piezoelectric element 38 so as to vibrate the dust-proof glass 37 at the input frequency f. Thereby, the dust-proof glass 37 is vibrated by the piezoelectric element 38, and the dust-proof glass 37 vibrates.

  Step S104 is processing for measuring the amplitude. The dust-proof glass 37 vibrates by the process of step S103. When the dustproof glass 37 vibrates, the vibration state (amplitude) of the dustproof glass 37 is detected by the piezoelectric element 38. This detection signal is output to the CPU 30. The CPU 30 calculates the amplitude amount of the dust-proof glass 37 from the detection signal and writes it in the built-in memory 31.

  Step S105 is processing for adding the change amount Δf to the frequency f. The CPU 30 adds the change amount Δf to the frequency f set in step S102. Thereby, the frequency which vibrates dustproof glass 37 next is set. Here, an example of the value of the change amount Δf is 20 Hz.

  Step S106 is processing to determine whether or not the frequency f exceeds the upper limit value fe1. When the frequency f set in step S105 exceeds the upper limit value fe1, the CPU 30 determines Yes in step S105. In this case, the process proceeds to step S107. On the other hand, when the set frequency f is equal to or less than the upper limit value fe1, the CPU 30 determines No in step S105 and returns to step S103. That is, if the determination process in step S106 is No, the processes in steps S103 to S105 are repeatedly executed. Thereby, the amplitude amount of the dust-proof glass 37 when the change amount Δf is changed between the frequency fs1 and the frequency fe1 is measured.

  Step S107 is processing for performing peak determination. By repeatedly executing the processing from step S103 to step S105, the amplitude amount of the dust-proof glass 37 at each frequency between the frequency fs1 and the frequency fe1 is measured. The CPU 30 reads the amplitude amount of the dust-proof glass 37 for each frequency, and performs peak determination using the read amplitude amount of the dust-proof glass 37. That is, the CPU 30 specifies the frequency at which the amplitude amount of the dustproof glass 37 is maximized as the first resonance frequency F1.

  Step S108 is processing for storing the identified first resonance frequency F1. The CPU 30 stores the first resonance frequency F1 specified by the process of step S107 in the built-in memory 31. By performing the process of step S108, the first vibration process ends.

  As shown in FIG. 3A, the frequency f for vibrating the dust-proof glass 57 is changed by Δf within the range from the frequency fs1 to the frequency fe1. If there is an apex (maximum point) of the amplitude value within the range from the frequency fs1 to the frequency fe1, the frequency at the apex becomes the resonance frequency. In this case, the frequency F1 when the amplitude value A1 is the apex is the first resonance frequency.

  Next, the second vibration operation in the foreign matter removal operation will be described with reference to the flowchart of FIG. The lower limit value of the second frequency band used in the second vibration operation is a frequency fs2, and the upper limit value is a frequency fe2. Note that the lower limit value fs2 and the upper limit value fe2 of the second frequency band are set by using an estimated frequency estimated from the first resonance frequency F1 obtained by the first vibration operation.

  For example, as shown in FIG. 3B, when the vibration-proof glass is vibrated, the resonance frequency generally varies due to individual differences in the dust-proof glass. Here, the dust-proof glass having a change in amplitude indicated by a solid line in FIG. Further, the dust-proof glass having the amplitude change indicated by the dotted line in FIG. 3B is referred to as dust-proof glass 37B, and the dust-proof glass having the amplitude indicated by the two-dot chain line is referred to as dust-proof glass 37C. For example, when comparing the dustproof glass 37A and the dustproof glass 37B, when the resonance frequency in the dustproof glass 37A is F1A and F2A, the resonance frequencies F1B and F2B in the dustproof glass 37B are more than the resonance frequencies F1A and F2A in the vibrationproof glass 37A. Becomes smaller. Further, when the dustproof glass 37A and the dustproof glass 37C are compared, the resonance frequencies F1C and F2C in the dustproof glass 37C are higher than the resonance frequencies F1A and F2A of the vibrationproof glass 37A. That is, it can be assumed that the resonance frequency in the dust-proof glass has a certain relationship with other resonance frequencies. That is, the second vibration operation is executed by utilizing a certain relationship between a certain resonance frequency and another resonance frequency.

  Step S201 is a process of reading the first resonance frequency F1, the coefficient k, and the coefficient f2. The first resonance frequency F1 is specified by the first vibration operation described above. The coefficient k is a coefficient used when estimating the second resonance frequency F2 from the first resonance frequency F1. For example, there are a plurality of resonance frequencies when the same member is vibrated, and the relationship between the resonance frequencies is constant. That is, the relationship of the second resonance frequency F2 = the first resonance frequency F1 × the coefficient k is established between the first resonance frequency F1 and the second resonance frequency F2. For this reason, the resonance frequency when the dust-proof glass 37 resonates and the average value of the resonance frequencies can be obtained by experiments and inspections, and the coefficient k can be obtained from these values.

  The coefficient f2 is a value used when obtaining a frequency band for vibrating the dust-proof glass 37. This coefficient f2 is a value that takes into account variations in the resonance frequency when the dustproof glass 37 resonates. This value f2 is also obtained from experiments and inspections.

  Step S202 is processing for obtaining the estimated frequency F2 'and the frequency band for vibrating the dust-proof glass 37. The CPU 30 obtains an estimated frequency for estimating another resonance frequency by multiplying the first resonance frequency F1 read in step S201 by the coefficient k. In the present embodiment, the case where the second resonance frequency F2 is obtained has been described, so that the second resonance frequency F2 is referred to as an estimated frequency F2 '.

  Further, the CPU 30 uses the estimated frequency F2 ′ and the coefficient f2 thus obtained, and the lower limit value fs2 (= F2′−f2) and the upper limit value fe2 (= F2 ′ + f2) of the frequency band for vibrating the dust-proof glass 37. Ask for.

  Step S203 is processing to store the obtained estimated frequency F2 ', the lower limit value fs2 of the frequency, and the upper limit value fe2. The CPU 30 stores the value obtained in step S202 in the built-in memory 31.

  Step S204 is processing for setting the frequency f for vibrating the dust-proof glass 37 to the lower limit value fs2 (f = fs2).

  Step S205 is processing to vibrate the dust-proof glass at the set frequency f. The CPU 30 outputs information on the set frequency f to the piezoelectric element driving circuit 18. In response to this, the piezoelectric element driving circuit 18 drives the piezoelectric element 38 so as to vibrate the dust-proof glass 37 at the input frequency f.

  Step S206 is processing for measuring the amplitude. The dust-proof glass 37 vibrates by the process of step S205. When the dust-proof glass 37 vibrates, the piezoelectric element 38 detects the amplitude of the vibrating dust-proof glass 37. This detection signal is output to the CPU 30. The CPU 30 calculates the amplitude amount of the dustproof glass 37 from the detection signal and writes it in the built-in memory 31.

  Step S207 is processing for adding the change amount Δf to the frequency f. The CPU 30 adds the change amount Δf to the frequency f set in step S204. Thereby, the frequency which vibrates dustproof glass 37 next is set. Here, an example of the value of the change amount Δf is 20 Hz.

  Step S208 is processing to determine whether or not the frequency f exceeds the upper limit value fe2. When the frequency f set in step S207 exceeds the upper limit value fe2, the CPU 30 sets the determination process in step S208 to Yes. In this case, the process proceeds to step S209. On the other hand, when the set frequency f is equal to or lower than the upper limit value fe2, the CPU 30 determines No in step S208 and returns to step S205. That is, if the determination process in step S208 is No, the processes in steps S205 to S207 are repeatedly executed. Thereby, the amplitude amount of the dust-proof glass 37 is measured while changing the frequency when the dust-proof glass 37 is vibrated by the change amount Δf between the frequency fs2 and the frequency fe2.

  Step S209 is processing for performing peak determination. By repeatedly executing the processing from step S205 to step S207, the amplitude amount of the dust-proof glass 37 at each frequency between the frequency fs2 and the frequency fe2 is measured. The CPU 30 reads the amplitude amount of the dust-proof glass 37 for each frequency, and performs peak determination using the read amplitude amount of the dust-proof glass 37. That is, the CPU 30 specifies the frequency at which the amplitude amount of the dustproof glass 37 is maximized as the second resonance frequency F2.

  Step S210 is processing to store the specified second resonance frequency F2. The CPU 30 stores the second resonance frequency F2 specified by the process of step S209 in the built-in memory 31.

  Step S211 is processing for determining whether or not the estimated frequency F2 'is different from the specified second resonance frequency F2. The CPU 30 reads the estimated frequency F2 'stored in the built-in memory 31 and the identified second resonance frequency F2. For example, if the estimated frequency F2 'and the second resonance frequency F2 are different values, the CPU 30 determines Yes in step S211 and proceeds to step S212. On the other hand, if the estimated frequency F2 'and the second resonance frequency F2 are the same value, the CPU 30 determines No in step S211 and ends the second vibration operation. That is, if the estimated frequency F2 'and the second resonance frequency F2 are the same value, the value of the coefficient k is maintained as it is.

  Step S212 is processing to calculate the coefficient k. The CPU 30 reads the first resonance frequency F1 and the second resonance frequency F2 stored in the built-in memory 31. Then, the coefficient k is calculated by dividing the second resonance frequency F2 by the first resonance frequency F1.

  Step S213 is processing for storing the coefficient k. The CPU 30 stores the calculated coefficient k in the built-in memory 31. As a result, the coefficient k is updated. When the process of step S213 ends, the second vibration operation ends.

  In the second vibration operation, the estimated frequency F2 'can be obtained by utilizing the relationship between the first resonance frequency and the second resonance frequency. By obtaining the estimated frequency F2 ', the width of the frequency band in which the dust-proof glass 37 is vibrated by the second vibration operation can be set narrow. Thereby, the operation time in the second vibration operation can be shortened, and the time related to the foreign substance removal processing can be shortened.

  Here, the dust-proof glass 37 is vibrated in each process of the first vibration operation and the second vibration operation described above. That is, by performing these vibration operations, dust adhering to the surface of the dust-proof glass 37 can be removed. Even if the dust attached to the surface of the dust-proof glass 37 cannot be removed by the first vibration operation, the second vibration operation is performed using a different frequency band. Therefore, the dust that could not be removed from the surface of the dust-proof glass 37. Can be reliably removed. Thus, it is possible to obtain a sufficient foreign matter removal performance by performing the foreign matter removal process of the present invention.

  Moreover, as shown in FIG.3 (c), the resonant frequency may each change with the dispersion | variation of dustproof glass, a secular change, and ambient temperature. Even in such a case, since it can be considered that a certain relationship is established between the first resonance frequency F1 and the resonance frequency F2, the dust-proof glass with respect to the estimated resonance frequency. A frequency band for vibrating 37 is set. Even in such a case, the second vibration operation can be appropriately executed, and the foreign matter removal performance is not deteriorated.

  In the present embodiment, the first resonance frequency is specified at the time of peak determination at the time of the first vibration operation, and the second resonance frequency is specified at the time of peak determination at the time of the second vibration operation. It is not always necessary to obtain the foreign substance removal process.

  For example, the processing shown in the flowchart of FIG. 4 as the processing for specifying the first resonance frequency F1, the processing shown in the flowchart of FIG. 5 as the processing for identifying the coefficient k and the second resonance frequency F2, and the foreign substance removal operation, respectively. You may perform as a different process. That is, the process for specifying the first resonance frequency F1 and the process for identifying the second resonance frequency F2 and the count k are executed in advance. Then, in the foreign substance removal operation, a frequency band for exciting the dustproof glass in the first vibration operation or the second vibration operation is set with respect to the first resonance frequency or the second resonance frequency specified, Perform each vibration action. In this case, by obtaining the first resonance frequency and the second resonance frequency in advance, the frequency band set during each vibration operation can be set narrow, so that the time required for the foreign substance removal processing can be shortened, Sufficient foreign matter removal performance can be obtained.

  In the present embodiment, the relationship between the first resonance frequency F1 and the second resonance frequency F2 is F1 <F2, but it is not necessary to be limited to this, and F1> F2.

  In the present embodiment, a value obtained by dividing the second resonance frequency F2 by the first resonance frequency F1 is used as the coefficient k, but the present invention is not limited to this. For example, the relationship between the first resonance frequency F1 and the second resonance frequency F2 is not a proportional relationship due to aging and variations of the dustproof glass 37, but a relationship represented by a quadratic curve, a logarithmic curve, or an exponential curve. Therefore, the coefficient k can be set to be changed based on these relationships.

FIG. 6 is a graph showing an example of the secular change of the coefficient k. As shown in FIG. 6, the value of the coefficient k is halved after 5 years. That is, when the initial value of the coefficient k and _{k 0,} the coefficient k of after 5 years k _{= k} 0/2, and the after a lapse of further 5 years, the coefficient k becomes k _{= k} 0/4. Note that when 5 years have passed, the value of the coefficient k does not halve, and after 10 years, the value of the coefficient k gradually decreases and converges to a predetermined value. Note that the value of convergence (in other words, the value in excess of k _0/8) more than half of the value of the coefficient k when the lapse of 10 years the value is.
Data on the secular change of the coefficient k based on the graph shown in FIG. 6 is stored in advance in the built-in memory of the digital camera. Then, the coefficient k can be obtained from the number of years since the digital camera was manufactured and the secular change data of the coefficient k, and can be used when calculating the estimated frequency in the foreign matter removing operation described above.

  In the present embodiment, the resonance frequency closest to the first resonance frequency F1 is specified as the second resonance frequency from the frequency band including the first resonance frequency F1 used in the foreign substance removal processing. However, the present invention is not limited to this. The resonance frequency that is used when the foreign matter removal process is actually executed can be obtained on the basis of the resonance frequency that is not used when the foreign matter removal process is actually executed.

  In the present embodiment, the digital camera 10 capable of executing the foreign substance removal process is described. However, in the process of manufacturing the digital camera 10, the foreign substance removal process shown in the flowcharts of FIGS. 4 and 5 is performed. Is also possible. In this case, in the process of manufacturing the digital camera 10, the processing shown in the flowcharts of FIGS. 4 and 5 is performed to specify the first resonance frequency F1 and the second resonance frequency F2 in advance. The identified first resonance frequency F1 and second resonance frequency F2 are stored in the built-in memory 31 of the digital camera 10. Then, during the foreign substance removal process in the digital camera 10, the first vibration operation using the stored first resonance frequency F1 and the second vibration operation using the second resonance frequency F2 are performed.

  In addition, the digital camera 10 having the configuration shown in FIG. 1 may be a foreign matter removal program that allows the CPU 30 to execute the processes of the flowcharts shown in FIGS. 4 and 5. In this case, the foreign matter removal program stored in the storage medium 34 is stored, and the CPU reads and executes the storage medium when the storage medium is attached to the digital camera. Examples of the storage medium include a memory card, an optical disk, and a magnetic disk.

  DESCRIPTION OF SYMBOLS 10 ... Digital camera, 16 ... Imaging unit, 18 ... Piezoelectric element drive circuit, 30 ... CPU, 36 ... Imaging element, 37 ... Dust-proof glass, 38 ... Piezoelectric element

Claims (9)

An image sensor that photoelectrically converts subject light;
An optical member disposed in front of the image sensor;
Vibration means for vibrating the optical member;
Estimating means for obtaining an estimated frequency at which the optical member is resonated using a first resonance frequency at which the optical member resonates, other than the first resonance frequency;
Control means for controlling the excitation means to vibrate the optical member by changing the frequency a plurality of times within a range of a frequency band including the estimated frequency;
Based on a vibration state of the optical member when the optical member is vibrated by changing the frequency a plurality of times within a frequency band including the estimated frequency, a second resonance frequency at which the optical member resonates is set. Identification means to identify;
Storage means for storing the second resonance frequency;
An imaging apparatus comprising: The imaging device according to claim 1,
The specifying means determines a frequency at which the amplitude amount is largest among amplitude amounts obtained when the optical member is vibrated while changing the frequency a plurality of times within a frequency band including the estimated frequency. An imaging apparatus characterized by being specified as the second resonance frequency. In the imaging device according to claim 1 or 2,
The imaging device is characterized in that the estimation means obtains the estimated frequency by multiplying the first resonance frequency by a coefficient. The imaging device according to claim 3.
The estimation device holds the coefficient when the specified second resonance frequency coincides with the estimated frequency. The imaging device according to claim 3.
The estimation means replaces the coefficient with a value obtained from the first resonance frequency and the second resonance frequency when the specified second resonance frequency does not match the estimated frequency. An imaging device. In the imaging device according to any one of claims 1 to 5,
The control means controls the vibration means to vibrate the optical member by changing the frequency a plurality of times within a preset frequency band range,
The specifying device specifies the first resonance frequency based on a vibration state of the optical member when the frequency is changed a plurality of times within a preset frequency band. . The imaging apparatus according to any one of claims 1 to 6,
The control means includes a first vibration operation that vibrates the optical member while changing the frequency a plurality of times within a range of a frequency band including the first resonance frequency, and a frequency band including the second resonance frequency. An image pickup apparatus that controls the excitation means so as to execute a second vibration operation that vibrates the optical member while changing the frequency a plurality of times within the range. An image sensor that photoelectrically converts subject light;
An optical member disposed in front of the image sensor;
Vibration means for vibrating the optical member;
In the foreign matter removing method in the imaging apparatus comprising:
Using the first resonance frequency when the optical member resonates, an estimation process for obtaining an estimated frequency estimated to resonate the optical member other than the first resonance frequency;
A control process for controlling the excitation means so as to vibrate the optical member by changing the frequency a plurality of times within the range of the frequency band including the estimated frequency;
Based on a vibration state of the optical member when the optical member is vibrated by changing the frequency a plurality of times within a frequency band including the estimated frequency, a second resonance frequency at which the optical member resonates is set. Specific processing to identify,
A storage process for storing the second resonance frequency;
A foreign matter removing method characterized by comprising: An image sensor that photoelectrically converts subject light;
An optical member disposed in front of the image sensor;
Vibration means for vibrating the optical member;
In the foreign matter removal program for controlling the imaging device provided with
Using the first resonance frequency when the optical member resonates, an estimation process for obtaining an estimated frequency estimated to resonate the optical member other than the first resonance frequency;
A control process for controlling the excitation means so as to vibrate the optical member by changing the frequency a plurality of times within the range of the frequency band including the estimated frequency;
Based on a vibration state of the optical member when the optical member is vibrated by changing the frequency a plurality of times within a frequency band including the estimated frequency, a second resonance frequency at which the optical member resonates is set. Specific processing to identify,
A storage process for storing the second resonance frequency;
Foreign matter removal program that can be executed by a computer.

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