Abstract:
The present invention provides an image sensing apparatus which comprises a vibration detector that detects vibration of the apparatus, a vibration correction unit that corrects vibration of an image, and a control unit that calculates a vibration correction signal based on a vibration detection signal from the vibration detector and controls the vibration correction unit. The control unit comprises a first detection unit that detects whether a first frequency obtained from the vibration detection signal and used for calculating the vibration correction signal falls within a first frequency band, a second detection unit that detects whether a second frequency obtained from the vibration detection signal and used for calculating the vibration correction signal falls within a second frequency band, a variable high frequency band pass unit that changes the pass band for the vibration detection signal on the high frequency side depending on detection results of the first and second detection unit, and a calculation unit that calculates the vibration correction signal from a vibration frequency of the vibration detection signal passed through the variable high frequency band pass unit and outputs the vibration correction signal to the vibration correction unit.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a vibration correcting function which corrects vibration of an image sensing apparatus represented by a video camera, etc., when sensing an image.  
         BACKGROUND OF THE INVENTION  
         [0002]    An image sensing apparatus such as a small video camera has a disadvantage that, because the apparatus shakes due to so-called camera shake or vibration when sensing an image, a fuzzy image is output or recorded. Therefore, as measures for eliminating such a disadvantage, an image sensing apparatus provided with a vibration correcting function which reduces influences of camera shake has been developed and already commercialized.  
           [0003]    There are various methods for detecting vibrations such as camera shake, for example, a method of directly detecting motion of an apparatus using an angular velocity sensor or angular acceleration sensor, and an electronic detection method for detecting motion of an image by comparing between images of successive fields or frames among image signals. On the other hand, there are means for correcting vibration, for example, one provided with a vibration correction optical system which optically adjusts an angle of the image sensing optical axis in a direction in which camera shake is cancelled and so-called electronic correcting means which electronically selects a range to be actually recorded or output (extraction range) of a sensed image by an image sensing element.  
           [0004]    A conventional example using an angular velocity sensor as vibration detecting means and using a vibration correction optical system as vibration correcting means will be explained below.  
           [0005]    [0005]FIG. 9 is a conceptual diagram of an image sensing optical system including a vibration correction optical system.  
           [0006]    In FIG. 9, an image sensing optical system  700  includes a fixed lens  701  which is fixed to a lens barrel (not shown), a zoom lens  702  which moves on a central axis c′ of the image sensing optical system  700  in horizontal direction as indicated by an arrow a, a shift lens  703  which moves two-dimensionally within the plane (direction indicated by an arrow b) which is perpendicular to the central axis c′, a focus lens  704  which corrects the movement of a focal plane due to a focusing function and movement of the zoom lens  702 , and an image sensing element  705  which forms an image of an object, arranged in the foregoing order, and is further provided with an actuator  706  which drives the shift lens  703  and a position detection sensor  707  which detects the position of the shift lens  703  at predetermined positions near the shift lens  703 .  
           [0007]    As shown in FIG. 10A, when camera shake, etc., causes the optical axis c to deviate from the central axis c′ of the image sensing optical system  700 , producing a displacement angle θ, it is possible, by driving the actuator  706  and moving the shift lens  703  to the position indicated by  703 ′ as shown in FIG. 10B, to optically align the optical axis c which is deviated on the fixed lens  701  side with respect to the shift lens  703  with the central axis c′ of the image sensing optical system on the image sensing element  705  side with respect to the shift lens  703 . Therefore, it is possible to correct the optical displacement angle θ produced by camera shake as described above through the above described operation and form an image of the object on the image sensing element  705  as an incident beam with vibration corrected by moving the shift lens  703  based on the camera shake.  
           [0008]    Then, an example of a configuration of a conventional image sensing apparatus shown in pp4-6, and FIGS. 2 and 3 of Japanese Patent Laid-Open No. 2000-39637, and pp3-4 and FIG. 1 of Japanese Patent Laid-Open No. 2000-66259 is shown in FIG. 11.  
           [0009]    In FIG. 11, the conventional image sensing apparatus is constructed of the aforementioned image sensing optical system  700  including the vibration correction system, an image sensing element  705  on which an optical image of an object is formed through the image sensing optical system  700 , a camera signal processing circuit  1519  which applies predetermined signal processing to the output from the image sensing element  705 , an angular velocity sensor  1501  which detects vibration of the apparatus, a high pass filter (hereinafter simply referred to as “HPF”)  1502  which removes a direct current (DC) component from the output of the angular velocity sensor  1501 , a first amplifier  1503  which amplifies the output from the HPF  1502  by a predetermined amount, a microcomputer  1505  which applies predetermined signal processing to the output from the first amplifier  1503 , a D/A converter  1515  which converts the output from the microcomputer  1505  to an analog signal, a driving circuit  1517  which issues a driving signal of the actuator  706  included in the image sensing optical system  700 , a second amplifier  1518  which amplifies the output from the position detection sensor  707  by a predetermined amount and an adder  1516  which adds up the output from the D/A converter  1515  and the output from the second amplifier  1518 .  
           [0010]    In this configuration, the angular velocity sensor  1501  outputs a vibration detection signal based on vibration of the apparatus, the vibration detection signal HPF  1502  removes the DC component from it, and then the first amplifier  1503  amplifies it by a predetermined amount. That is, the configuration from the angular velocity sensor  1501  to the first amplifier  1503  causes the vibration detection signal from the angular velocity sensor  1501  to convert to a vibration detection signal processed with predetermined band restriction and amplification and the vibration detection signal is input to the microcomputer  1505  which controls the image sensing apparatus. The vibration detection signal input to the microcomputer  1505  is subjected to predetermined signal processing to calculate a control amount of vibration correction (hereinafter simply referred to as a “correction target value”). This predetermined signal processing will be described later.  
           [0011]    Then, the correction target value calculated by the microcomputer  1505  is converted from a digital signal to an analog signal at the D/A converter  1515 , input to the adder  1516  and added to a feedback signal from the position detection sensor  707  of the shift lens  703  supplied through the second amplifier  1518 . The output signal from the adder  1516  is supplied to the driving circuit  1517  and the driving circuit  1517  issues a driving signal to the actuator  706  and drives the shift lens  703 . This allows the displacement θ to be optically corrected as explained in FIGS.  10 A and  10 B, causing the object image to be formed on the image sensing element  705  as a beam with vibration corrected.  
           [0012]    Then, the electric signal photoelectrically converted by the image sensing element  705  is led through a camera signal processing circuit  1519  and supplied to a recording/reproducing section (not shown), etc.  
           [0013]    Next, the signal processing in the microcomputer  1505  will be explained.  
           [0014]    [0014]FIG. 12 shows a signal processing system in the microcomputer  1505 , including an A/D converter  1506  which converts the input vibration detection signal from an analog signal to a digital signal, an HPF  1507  which removes a DC component from the output of the A/D converter  1506 , a phase compensation section  1508  which phase-compensates the output of the HPF  1507 , a variable HPF  1509  which restricts the pass band of the output of the phase compensation section  1508 , a first integrator  1510  which integrates the output of the variable HPF  1509 , a frequency detection section  1511  which detects the vibration frequency from the output of the A/D converter  1506  through the HPF  1507  and a vibration correction frequency control section  1514  which decides the vibration state of the apparatus from the output of the frequency detection section  1511  and controls the frequency for correcting the vibration. The frequency detection section  1511  includes a second integrator  1512  which integrates the output of the A/D converter  1506  which has passed through the HPF  1507  and a frequency calculation section  1513  which calculates the frequency from this integrated output.  
           [0015]    In the above described configuration, the input vibration detection signal is converted at the A/D converter  1506  from an analog vibration signal to a digital vibration signal and then remove the DC component generated through A/D conversion, etc., at the HPF  1507 . Therefore, the cutoff frequency of the HPF  1507  is sufficiently low. Then, at the phase compensation section  1508 , the vibration detection signal from which the DC component is removed is phase-compensated for a phase delay in a high frequency band in such a way that the phase characteristic becomes flat up to a predetermined frequency band, then subjected to predetermined pass band restriction and phase compensation which will be described later at the variable HPF  1509  whose cutoff frequency is variable, further subjected to integration processing at the first integrator  1510  to convert the angular velocity signal to an angular displacement signal whereby a correction target value is obtained and supplied to the D/A converter  1515 .  
           [0016]    Furthermore, the output of the HPF  1507  is input to the phase compensation section  1508  as shown in FIG. 12 and at the same time also input to the frequency detection section  1511 , where the vibration frequency of the apparatus is detected. The detection of the vibration frequency will be described later.  
           [0017]    Then, the detected vibration frequency is input to the vibration correction frequency control section  1514 , where a cutoff frequency is selected from table data corresponding to the vibration frequency from the frequency detection section  1511  and set in the variable HPF  1509 . More specifically, control is performed in such a way that the cutoff frequency remains at a specified value or the cutoff frequency is shifted gradually from the cutoff frequency of a specified value to the high frequency side or the cutoff frequency is returned gradually from a state in which it has been shifted to the high frequency side to the cutoff frequency of a specified value (hereinafter simply referred to as “adaptive control”) and the signal is phase-compensated for a phase delay in the high frequency band which cannot be phase-compensated by the phase compensation section  1508 .  
           [0018]    Then, the detection of a vibration frequency will be explained.  
           [0019]    As shown in FIG. 12, the frequency detection section  1511  includes the second integrator  1512  and frequency calculation section  1513 . The second integrator  1512  integrates the output of the A/D converter  1506  which has passed through the HPF  1507 , thereby converts the angular velocity signal to an angular displacement signal and calculates a second angular displacement signal. Based on the above described calculated second angular displacement signal, the frequency calculation section  1513  calculates the frequency and detects the vibration frequency of the apparatus.  
           [0020]    Next, the calculation of an angular displacement signal for frequency detection and calculation of the frequency will be explained.  
           [0021]    [0021]FIG. 13 shows an input/output characteristic of the second integrator  1512  which calculates an angular displacement signal to calculate the vibration frequency of the apparatus, which shows the frequency on the abscissa and gain on the ordinate.  
           [0022]    As is apparent from FIG. 13, the output of the second integrator  1512  has an integration characteristic in which the output is greater in a low frequency band and smaller in a high frequency band. Therefore, the high frequency band which is mixed with the output of the HPF  1507  input to the second integrator  1512  attenuates and the angular displacement signal of the low frequency band at a large amplitude level is calculated.  
           [0023]    Next, the operation of the frequency calculation section  1513  which calculates a vibration frequency of the apparatus from the calculated angular displacement signal will be explained using FIG. 14.  
           [0024]    [0024]FIG. 14 is a flow chart showing frequency detection processing carried out in the microcomputer  1505  and rough description of this processing will be given first.  
           [0025]    In step S 1101  in this figure, frequency detection is started and in step S 1102 , the number of increase/decrease turning points of the vibration signal calculated by the second integrator  1512  is counted first. Then, in next step S 1103  the count value is stored in a register and in step S 1104  the count value is compared with a predetermined first threshold (th1). If the count value is equal to or lower than the predetermined first threshold (th1), the process moves on to step S 1105 , where it calculates a first frequency, then moves on to step S 1108  and finishes the frequency detection.  
           [0026]    On the other hand, if the count value is greater than the first threshold (th1) in step S 1104 , the process moves on to step S 1106 , where it compares the number of times (count value&gt;th1) occurs consecutively with a predetermined second threshold (th2). As a result, if the number of times (count value&gt;th1) is equal to or lower than the second threshold (th2), the process moves on to step S 1108 , where it finishes the frequency detection. If the number of times (count value&gt;th1) is greater than the second threshold (th2), the process moves on to step S 1107 , where it calculates a second frequency and then moves on to step S 1108  and finishes the frequency detection.  
           [0027]    Then, the specific operation of the frequency detection will be explained using FIG. 14.  
           [0028]    As the method for frequency detection, the number of increase/decrease turning points of the vibration signal per a unit time is counted and the counted number is regarded as the detected frequency.  
           [0029]    In step S 1101 , frequency detection which is carried out at a period (e.g., 500 [ms]) longer than a vibration correction control processing period (e.g., 1 [ms]) is started. First in step S 1102 , the number of increase/decrease turning points of an angular displacement signal is counted whereby the increase/decrease subjected to the counting is a difference between previous sampling data and latest sampling data of an angular displacement signal sampled at a predetermined period (e.g., 10 [ms]) which exceeds a predetermined threshold. Then in next step S 1103 , the counted value is stored in a register. This register is a shift register constructed in such a way as to be able to store a plurality of sample data (n=x), shift data every time the count value is updated and erase the oldest data.  
           [0030]    Then in step S 1104 , the latest count value (number of increase/decrease turning points) is compared with the first threshold (th1). For example, when the first threshold (th1) is set to “12” and the latest count value is “10”, the updated count value as a result of comparison becomes th1 or less (NO) and the process moves on to step S 1105 . Then, in this step S 1105 , the frequency per a unit time is calculated from the number of increase/decrease turning points “10” which is the latest count value stored in the register. The number of increase/decrease turning points in one period is 2 and 1 [Hz], that is, since the frequency is ½ of the number of increase/decrease turning points, that is “10/2=5” and a frequency of 5 [Hz] is calculated. After the frequency is calculated, the process moves on to step S 1108  and finishes the frequency detection processing.  
           [0031]    Furthermore, in above step S 1104 , if the latest count value (number of increase/decrease turning points) is higher than th1, for example if the first threshold (th1) is “12” and latest count value is “16”, the updated count value is higher than th1 (YES). In this case, the process moves on to step S 1106 , where the number of times that the comparison condition (count value&gt;th1) in step S 1104  holds consecutively is compared with the second threshold (th2). This processing is carried out to improve the reliability of counting because when the count in step S 1102  increases sporadically due to noise, etc., the comparison condition (count value&gt;th1) in step S 1104  is satisfied.  
           [0032]    When the number of times the comparison condition (count value&gt;th1) in step S 1104  is satisfied is equal to or lower than a predetermined threshold (th2) (No in step S 1106 ), the process moves on to step S 1108 , where it finishes the processing of frequency detection. That is, the detected frequency is not updated.  
           [0033]    On the other hand, when the number of times the comparison condition (count value&gt;th1) in step S 1104  is satisfied is greater than a predetermined threshold (th2) ((count value)&gt;th1))&gt;th2 holds (YES in step S 1106 ), the process moves on to step S 1107 , where the latest count value stored in the register is compared with count values stored in the past and adopts a minimum value as the detected frequency. More specifically, assuming that the count values stored in the register are for example, 16, 18 and 18, that is, n=3, the microcomputer compares them and selects 16 as a minimum value. In this case, the frequency is 16/2=8 as described above and this means that a frequency 8 [Hz] is calculated.  
           [0034]    The minimum value is regarded as the detection frequency because the camera shake frequency relatively tends to concentrate on a low frequency (several [Hz] to 10 [Hz]) and the cutoff frequency of the variable HPF  1509  is controlled based on the frequency detected assuming the use on a vehicle, etc., and therefore this is intended to reduce sacrificing of the vibration correction effect on the low frequency side to a lowest possible level even when the vibration correction frequency is shifted to the high frequency side. Then, the microcomputer moves on to step S 1108  and finishes the processing of frequency detection.  
           [0035]    Next, the operation of the vibration correction frequency control section  1514  which determines the vibration state of the apparatus according to the detected vibration frequency and sets the cutoff frequency of the variable HPF  1509  will be explained below.  
           [0036]    A predetermined frequency threshold (fth) is set in the vibration correction frequency control section  1514  for the vibration frequency detected by the frequency detection section  1511 . Therefore, the vibration correction frequency control section  1514  compares the detected vibration frequency with the predetermined frequency threshold (fth), decides whether the detected vibration frequency is higher than fth or not, and performs adaptive control, based on the determination result, such as to decide whether to continue to use the predetermined specified value as the cutoff frequency of the variable HPF  1509  or shift it from the specified value to the high frequency side gradually or return it from the state in which it has been shifted to the high frequency side to the specified value gradually.  
           [0037]    Next, the frequency characteristic of the variable HPF  1509  when adaptive control is performed will be explained using FIG. 15A and FIG. 15B. FIG. 15A shows a gain characteristic and FIG. 15B shows a phase characteristic.  
           [0038]    The variable HPF  1509  has a frequency characteristic up to the normal camera shake frequency band (e.g., approximately 3 to 8 [Hz]) indicated by a gain  1201  and phase  1202  set for a predetermined cutoff frequency fc and the cutoff frequency remains at the specified value fc. However, when the apparatus is fixed to a vehicle, etc., and the vehicle moves and when a frequency (e.g., approximately 20 [Hz]) exceeding the frequency of camera shake is detected, the vibration correction frequency control section  1514  controls so that the cutoff frequency of the variable HPF  1509  is shifted to the high frequency side gradually based on the detection frequency. The frequency characteristic when the cutoff frequency of the variable HPF  1509  is shifted gradually to the high frequency side is gain  1201 ′ and phase  1202 ′ in the case of the cutoff frequency fc′ shown in FIG. 15A and FIG. 15B. Furthermore, when the detected frequency changes from the frequency exceeding the frequency of camera shake to a normal frequency of camera shake, the vibration correction frequency control section  1514  controls so that the cutoff frequency fc′ of the variable HPF  1509  is gradually shifted to fc.  
           [0039]    Thus, it is possible to make the cutoff frequency of the variable HPF  1509  variable through adaptive control. Since the phase characteristic when the cutoff frequency is shifted to the high frequency side (fc′) is a leading phase ( 1202 ′), phase compensation for the high frequency band which will be described later is performed.  
           [0040]    Then, phase compensation for a phase delay of a high frequency band will be explained.  
           [0041]    [0041]FIGS. 16A and 16B show a frequency characteristic from the angular velocity sensor  1501  to the output of the vibration correction system and reference numeral  1301  in FIG. 16A shows a gain characteristic and reference numeral  1302  in FIG. 16B shows a phase characteristic.  
           [0042]    In FIGS. 16A and 16B, a frequency band  1303  shows a vibration correctable band and it is for example, frequency f1=1 Hz, f2=20 Hz and f3=30 Hz. The range of a band  1304  where the gain attenuates shows a band in which vibration correction is disabled. In the bands between frequencies f2 and f3, the phase shows a lag in the high frequency band in the vibration correctable range as shown in FIG. 16B. Therefore, the phase characteristic of the variable HPF  1509  which changes as the cutoff frequency of the variable HPF  1509  is shifted to the high frequency side (leading phase) makes it possible to phase-compensate the high frequency band in which a phase delay occurs and improves the vibration suppression effect of a high frequency band equal to or higher than the normal camera shake frequency by bringing the phase characteristic closer to flat.  
           [0043]    The vibration signal that passes through the variable HPF  1509  which is adaptively controlled in this way is integrated by the first integrator  1510  whereby an angular displacement signal is output as a correction target value.  
           [0044]    Next, the processing whereby the aforementioned content is executed in the microcomputer  1505  will be explained with reference FIGS. 17 and 18.  
           [0045]    [0045]FIG. 17 is a flow chart of the vibration correction processing executed in the microcomputer  1505  and is the processing for interrupting the overall processing of the microcomputer  1505  in a predetermined period (e.g., 1 [ms]).  
           [0046]    In FIG. 17, the process start by an interruption in step S 1401  and an analog vibration detection signal captured by the A/D converter  1506  is converted to a digital vibration detection signal in step S 1402  first. Then, in next step S 1403 , the HPF  1507  removes the DC component generated through A/D conversion. Then in next step S 1404 , the phase compensation section  1508  phase-compensates for a predetermined band of the vibration detection signal whose DC component has been removed. Then, in step S 1405 , the variable HPF  1509  applies predetermined band restriction on the vibration detection signal undergone predetermined phase compensation.  
           [0047]    In next step S 1406 , the first integrator  1510  integrates the vibration detection signal undergone the predetermined band restriction to calculate a first angular displacement signal. Then, in next step S 1407 , the first angular displacement signal is output from the microcomputer  1505  as the correction target value and in next step S 1408 , the second integrator  1512  integrates the output of the HPF  1507  to calculate a second angular displacement signal for frequency detection. Then, in step S 1409 , the microcomputer  1505  finishes interruption to the overall processing under its control.  
           [0048]    Next, with reference to the flow chart in FIG. 18, the processing of calculating a frequency from the second angular displacement signal calculated for frequency detection, deciding the vibration state of the apparatus and controlling the cutoff frequency of the variable HPF  1509  will be explained. This processing is carried out at a period different from the period of the processing in FIG. 17 (e.g., 500 [ms]).  
           [0049]    In FIG. 18, the processing of detecting a frequency is started at step S 1451  and in step S 1452 , the frequency calculation section  1513  calculates the vibration frequency of the apparatus based on the second angular displacement signal calculated in step S 1408  in FIG. 17. The method of detecting the frequency is as described with reference to FIG. 14.  
           [0050]    Then, in step S 1453 , the detected frequency is compared with a predetermined threshold (fth). When the detected frequency is higher than fth (YES), the microcomputer  1505  decides that the high frequency is detected and the process moves on to step S 1454 , where a cutoff frequency of the variable HPF  1509  is set based on the frequency detected in step S 1452 . In this case, the cutoff frequency is shifted gradually to the high frequency side. After setting the cutoff frequency of the variable HPF  1509 , the process moves on to step S 1456  and finishes the frequency detection and cutoff frequency setting processing.  
           [0051]    Furthermore, when the comparison result in step S 1453  is equal to or lower than the threshold (NO), the microcomputer  1505  decides that a normal vibration frequency is detected and the process moves on to step S 1455 , where a specified cutoff frequency during normal vibration correction is set in the variable HPF  1509  and the process moves on to step S 1456  and finishes the frequency detection and cutoff frequency setting processing. The cutoff frequency set by the variable HPF  1509  is updated when the next frequency detection processing is executed and the cutoff frequency of the variable HPF  1509  is controlled as appropriate. The image sensing apparatus provided with the aforementioned vibration correction function allows image sensing with a normal handheld camera or vibration correction when mounted on a vehicle, etc.  
           [0052]    The vibration correction function mounted on the image sensing apparatus performs similar corrections in at least two directions; vertical direction and horizontal direction. Since corrections in these two directions are similar operations, for simplicity of explanation of the conventional example, an operation in one direction was explained to represent them. Further, the driving circuit and actuator that drive the zoom lens  702  and focus lens  704 , mechanism and control for exposure control are omitted in the above explanation.  
           [0053]    According to the above described conventional example, when an image sensing apparatus such as a video camera provided with a vibration correction function is placed on a table on a ship, etc., for image sensing in an operating environment in which vibration exerted on the apparatus consists of a mixture of a low frequency vibration of reeling of the ship and a high frequency vibration due to vibration of the engine transmitted through structures of the ship, the frequency detection section  1511  detects the low frequency preferentially as explained in the flow chart in FIG. 14, failing to detect the high frequency and detect a vibration frequency of the high frequency band.  
           [0054]    Thus, even when a mixture of low frequency and high frequency vibration which is correctable by camera shake correction is applied to the apparatus, the vibration correction frequency control section  1514  determines that the vibration is of only the low frequency, tries to adjust adaptive control for making a cutoff frequency of the variable HPF  1509  variable to the low frequency and the microcomputer  1505  outputs a correction target value for vibration correction which matches the low frequency. This prevents sufficient vibration correction of the high frequency band due to a phase delay of the high frequency band, showing a defect that the vibration suppression performance of the high frequency band is inferior to that of the low frequency band.  
           [0055]    This reflects in such a phenomenon that when for example, an image with black and white stripe patterns is sensed and a comparison is made between a case where there is vibration of a low frequency band and a case where there is vibration of a high frequency band, the boundary between black and white appears blurred when there is vibration of a high frequency band, resulting in a defect that resolution appears deteriorated with the presence of vibration of the high frequency band.  
         SUMMARY OF THE INVENTION  
         [0056]    The present invention has been made in consideration of the above situation, and has as its object to allow more appropriate vibration correction even when vibration of a low frequency and vibration of a high frequency are mixed.  
           [0057]    According to the present invention, the foregoing object is attained by providing an image sensing apparatus comprising:  
           [0058]    a vibration detector that detects vibration of the apparatus;  
           [0059]    a vibration correction unit that corrects vibration of an image caused by vibration of the apparatus; and  
           [0060]    a control unit that calculates a vibration correction signal based on a vibration detection signal from the vibration detector and controls the vibration correction unit, wherein the control unit comprises:  
           [0061]    a first detection unit that detects whether a first frequency obtained from the vibration detection signal and used for calculating the vibration correction signal falls within a first frequency band which is equals to or lower than a predetermined frequency;  
           [0062]    a second detection unit that detects whether a second frequency obtained from the vibration detection signal and used for calculating the vibration correction signal falls within a second frequency band exceeding the predetermined frequency or not;  
           [0063]    a variable high frequency band pass unit that changes the pass band for the vibration detection signal on the high frequency side depending on cases 1) where the first frequency falls within the first frequency band and the second frequency does not fall within the second frequency band, 2) where the first frequency does not fall within the first frequency band and the second frequency falls within the second frequency band, and 3) where the first frequency falls within the first frequency band and the second frequency falls within the second frequency band simultaneously; and  
           [0064]    a calculation unit that calculates the vibration correction signal from a vibration frequency of the vibration detection signal passed through the variable high frequency band pass unit and outputs the vibration correction signal to the vibration correction unit.  
           [0065]    Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0066]    The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.  
         [0067]    [0067]FIG. 1 is a block diagram showing a configuration of an image sensing apparatus according to a first embodiment of the present invention;  
         [0068]    [0068]FIG. 2 is a characteristic diagram of a configuration made up of the second HPF and third integrator in FIG. 1;  
         [0069]    [0069]FIG. 3 is a flow chart showing processing executed in the microcomputer according to the first embodiment of the present invention;  
         [0070]    [0070]FIG. 4 is a flow chart showing frequency detection and cutoff frequency setting processing executed in the microcomputer according to the first embodiment of the present invention;  
         [0071]    [0071]FIG. 5 is a block diagram showing a configuration of a microcomputer according to a second embodiment of the present invention;  
         [0072]    [0072]FIG. 6 is a block diagram of the correction target value switching unit in FIG. 5;  
         [0073]    [0073]FIG. 7 is a flow chart showing processing executed in the microcomputer according to the second embodiment of the present invention;  
         [0074]    [0074]FIG. 8 is a flow chart showing frequency detection, cutoff frequency setting and correction target value switching processing executed in the microcomputer according to the second embodiment of the present invention;  
         [0075]    [0075]FIG. 9 schematically illustrates an arrangement of lenses of a conventional image sensing optical system;  
         [0076]    [0076]FIG. 10A and FIG. 10B illustrate a driving state of a shift lens when the optical axis is deviated from the center of the image sensing optical system;  
         [0077]    [0077]FIG. 11 is a block diagram showing a configuration of the conventional image sensing apparatus;  
         [0078]    [0078]FIG. 12 is a block diagram showing a configuration of the microcomputer in FIG. 11;  
         [0079]    [0079]FIG. 13 is a characteristic diagram of the second integrator in FIG. 12;  
         [0080]    [0080]FIG. 14 is a flow chart showing the vibration frequency detection processing of the conventional image sensing apparatus;  
         [0081]    [0081]FIG. 15A and FIG. 15B are explanatory view for explaining vibration detection signal filtering processing of the conventional image sensing apparatus;  
         [0082]    [0082]FIG. 16A and FIG. 16B are characteristic diagrams showing a general vibration correction characteristic;  
         [0083]    [0083]FIG. 17 is a flow chart showing the processing executed in the microcomputer of the conventional image sensing apparatus; and  
         [0084]    [0084]FIG. 18 is a flow chart showing the frequency detection and cutoff frequency setting processing executed in the microcomputer of the conventional image sensing apparatus. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0085]    Preferred embodiments of the present invention will be described in detail in accordance with the accompanying drawings.  
         [0086]    [First Embodiment] 
         [0087]    [0087]FIG. 1 is a block diagram showing a configuration of an image sensing apparatus according to a first embodiment of the present invention.  
         [0088]    In FIG. 1, reference numeral  1  denotes a second HPF which allows a predetermined high frequency component of a vibration detection signal to pass;  2 , a third integrator which calculates an angular displacement signal from the output of the second HPF  1 ;  3 , a second frequency calculation section which calculates a frequency; and  4 , a vibration correction frequency control section which determines a vibration state from the vibration frequency and controls a frequency for correcting vibration. The third integrator  2  and the second frequency calculation section  3  are included in a second frequency detection section  10  which detects a second frequency.  
         [0089]    Other components such as an angular velocity sensor  1501 , HPF  1502 , amplifier  1503 , microcomputer  1505 ′ and components included in the microcomputer  1505 ′ such as processing sections  1506  to  1511 , D/A converter  1515 , adder  1516 , driving circuit  1517 , amplifier  1518 , image sensing optical system  700 , and components included in the image sensing optical system such as lens groups  701  to  704 , actuator  706  and position detection sensor  707  of the shift lens, image sensing element  705  and camera signal processing circuit  1519  have the same configurations as those of the conventional example shown in FIG. 11 and FIG. 12, and therefore they are assigned the same reference numerals and duplicate explanations of their configurations and operations will be omitted.  
         [0090]    However, for convenience&#39;s sake, the frequency detection section  1511  and a frequency detected by the frequency detection section  1511  in the conventional example are called a “first frequency detection section  1511 ” and “first frequency” in this first embodiment and further the HPF  1507  and frequency calculation section  1513  are called a “first HPF 1507” and “first frequency calculation section 1513.” 
         [0091]    The operations of the second HPF  1 , third integrator  2 , frequency calculation section  3  and vibration correction frequency control section  4  in the above described configuration will be explained.  
         [0092]    The second HPF  1  is a high pass filter which cuts off frequency components lower than a predetermined cutoff frequency (fc1) from the vibration signal with no DC component which has passed through the first HPF  1507 . More specifically, a value equal to or greater than a normal camera shake frequency band (e.g., 10 [Hz]) may be set as fc1, but optimum cutoff frequencies for respective apparatuses are preset. The high frequency vibration signal obtained at the second HPF  1  is subjected to integration processing by the third integrator  2  and converted to a high frequency displacement signal.  
         [0093]    The second frequency calculation section  3  calculates a main frequency component included in the high frequency angular displacement signal through the processing similar to that explained in the conventional example. The frequency calculated by the second frequency calculation section  3  in particular becomes a second frequency limited to a frequency equal to or higher than fc1 because the amount of displacement of the low vibration frequency component of the vibration displacement signal obtained from the third integrator  2  is cut off by the fc1 of the second HPF  1 .  
         [0094]    Here, a typical input/output characteristic after the second HPF  1  and second frequency calculation section  3  will be explained with reference to FIG. 2 in brief.  
         [0095]    [0095]FIG. 2 shows an input/output characteristic of the third integrator  2  and shows a frequency on the abscissa and a gain on the ordinate. In FIG. 2, reference numeral  201  expressed with a dotted line is an original integration characteristic and  202  shows an integration characteristic of a low frequency band which has attenuated by the second HPF  1 . Since it is a characteristic with the gain of the low frequency band attenuated by the pass band restriction of the second HPF  1 , the third integrator  2  outputs a signal of a large amplitude level equal to or higher than the cutoff frequency of the second HPF  1 . With reference to FIG. 1 again, the function of the vibration correction frequency control section  4  will be explained.  
         [0096]    The second frequency detected by the second frequency detection section  10  constructed of the third integrator  2  and the second frequency calculation section  3  is input to the vibration correction frequency control section  4 . Then, the vibration correction frequency control section  4  determines the state of vibration exert on the apparatus based on the first frequency detected by the first frequency detection section  1511  and the second frequency detected by the second frequency detection section  10  and controls the frequency for correcting vibration.  
         [0097]    More specifically, the vibration correction frequency control section  4  decides whether the vibration is of only a low frequency, only high frequency or a mixture of low frequency and high frequency and controls the cutoff frequency of the variable HPF  1509  so as to keep a specified value or make it variable.  
         [0098]    This processing will be explained using the flow charts shown in FIGS. 3 and 4.  
         [0099]    [0099]FIG. 3 is a flow chart of vibration correction processing executed in the microcomputer  1505 ′ and at step S 301 , processing of interrupting the overall processing of the microcomputer  1505 ′ starts at a predetermined period (e.g., 1 [ms]) and a captured analog vibration detection signal is converted to a digital vibration detection signal by the A/D converter  1506  in step S 302 . Then, in next step S 303 , the first HPF  1507  removes the DC component generated through the A/D conversion. Then, in next step S 304 , the phase compensation section  1508  phase-compensates a predetermined band of the vibration detection signal whose DC component has been removed by the first HPF  1507 . Then, in step S 305 , the variable HPF  1509  applies predetermined band restriction to the vibration detection signal undergone predetermined phase compensation by the variable HPF  1509 .  
         [0100]    Then, in step S 306 , the first integrator  1510  integrates a vibration detection signal undergone the predetermined band restriction to calculate the first angular displacement signal, and the process moves on to step S 307 , where the first angular displacement signal is output from the microcomputer  1505 ′ as a correction target value. In this way, vibration correction is performed. In next step S 308 , the second integrator  1511  integrates the output of the first HPF  1507  and outputs a second angular displacement signal for detection of the first frequency. In next step S 309 , the second HPF  1  applies predetermined band restriction to the output of the first HPF  1507 , the process moves on to step S 310 , where the third integrator  2  integrates the vibration detection signal undergone the band restriction in step S 309  and outputs a third angular displacement signal for detection of the second frequency. Then in step S 311 , the microcomputer  1505 ′ terminates interruption to all processing under its control.  
         [0101]    Next, frequency detection and cutoff frequency setting processing of the variable HPF  1509  will be explained.  
         [0102]    [0102]FIG. 4 is a flow chart of frequency detection and cutoff frequency setting processing for the variable HPF and this processing is carried out at a period different from the processing in FIG. 3 (e.g., 500 [ms]).  
         [0103]    First, this processing will be roughly explained.  
         [0104]    In FIG. 4, in step S 351 , frequency detection and cutoff frequency setting processing for the variable HPF are started and in step S 352 , the first frequency detection section  1511  detects the first frequency based on the second angular displacement signal calculated in step S 308  in FIG. 3 and in next step S 353 , the second frequency detection section  10  detects the second frequency based on the third angular displacement signal calculated in step S 319  in FIG. 3. Then, in next step S 354 , the first frequency is compared with a first threshold (fth1) and if the first frequency is greater, the process moves on to step S 355  and sets a cutoff frequency of the variable HPF  1509  according to the first frequency. On the other hand, if the first frequency is equals to or smaller than the first threshold (fth1), the process moves onto step S 356 , where the second frequency is compared with a predetermined second threshold (fth2) and if the second frequency is equals to or smaller than the first threshold (fth2), that is, if it can be reconfirmed that the vibration is truly only of a low frequency, the process moves on to next step S 355 . On the contrary, if the second frequency is greater, the process moves on to step S 357  and a cutoff frequency of the variable HPF  1509  according to the second frequency is set. Then in step S 358 , frequency detection and cutoff frequency setting for the variable HPF are ended.  
         [0105]    Next, a detailed operation of the vibration correction frequency control section  4  of the above described processing will be explained using the same flow chart of FIG. 4.  
         [0106]    At step S 351 , frequency detection and cutoff frequency setting processing are started and a first frequency exerted on the apparatus is detected in step S 352  and a second frequency exerted on the apparatus closer to the high frequency side than the first frequency is detected in step S 353 . These frequencies are used to decide the vibration state of the apparatus as described below, but the operation about the detection of this frequency is the same as the frequency detection operation of the conventional example explained with reference to FIG. 14, and thus details thereof will be omitted.  
         [0107]    In next step S 354 , it is decided whether the first frequency detected by the first frequency detection section  1511  is higher than a predetermined first threshold (hereinafter referred to as “fth1”) or not. A frequency in a normal camera shake frequency band can be set as fth1 (e.g., 6 [Hz]). If the above described comparison result shows that the first frequency is higher than fth1 (YES), the process moves on to step S 355 , where since the first frequency is higher than fth1 , it is decided that the vibration exerted on the apparatus is vibration only of a high frequency higher than normal camera shake frequency. Accordingly, the cutoff frequency of the variable HPF  1509  is gradually shifted from the setting at the time of normal camera shake correction to the high frequency side based on the first frequency detected, to carry out vibration correction of the high frequency band. This improves the vibration suppression performance of the high frequency band and can reduce deterioration of resolution of the sensed image caused by the high frequency component.  
         [0108]    On the other hand, if the comparison result in step S 354  is that the first frequency is equals to or lower than fth1 (NO), since the first frequency is a low frequency equal to or lower than the normal camera shake frequency band and the process moves on to step S 356  and a comparison is made between the second frequency detected by the second frequency detection section  10  enabling detection of higher frequencies than the conventional first frequency detection section  1511  with a predetermined second threshold (hereinafter referred to as “fth2”). A frequency equal to or higher than a normal camera shake frequency (e.g., 10 [Hz]) can be set as fth2 and it is checked here whether the vibration frequency exerted on the apparatus does not truly include a high frequency component or not. If this comparison result shows that the second frequency is equals to or 1 ower than fth2 (No), the process moves on to step S 355 , where since the comparison result in step S 354  above is equals to or lower than fth1 and the comparison result in step S 356  above is equals to or lower than fth2, it is decided that the vibration state of the apparatus is only of a low frequency equal to or lower the normal camera shake frequency band and the cutoff frequency of the variable HPF  1509  is kept to the setting at the time of normal camera shake correction based on the first frequency. Therefore, normal camera shake correction is performed.  
         [0109]    The setting of the cutoff frequency of the variable HPF so far is carried out by deciding whether the frequency of vibration exerted on the apparatus is a low frequency or high frequency. Next, processing for a case where a vibration of mixture of a low frequency and high frequency is exerted on the apparatus will be explained.  
         [0110]    If, as the comparison result in step S 354  above, the first frequency is equal to or lower than fth1 (NO), since the detected first frequency is a low frequency, the process moves on to step S 356  and a comparison is made between the second frequency detected by the second frequency detection section  10  and fth2. Then, if the second frequency is greater than fth2 (YES), since the second frequency is a high frequency, the process moves on to step S 357 . Here, since the comparison result in step S 354  indicates that the first frequency is equal to or lower than fth1 , and the comparison result in step S 356  above indicates that the second frequency is greater than fth2, it is decided that the vibration state of the apparatus is a mixture of a normal camera shake frequency band and high frequency band and the cutoff frequency of the variable HPF  1509  is gradually shifted from the setting at the time of normal camera shake correction to the high frequency side based on the detected second frequency to thereby perform vibration correction of the high frequency band. Thus, vibration correction of a high frequency band is given priority, and therefore the vibration suppression performance of the normal camera shake frequency band shows a tendency of declination, but the vibration suppression performance of the high frequency band improves, which reduces the deterioration of resolution of a sensed image caused by the high frequency component.  
         [0111]    Thus, when the vibration correction frequency control section  4  detects only a low frequency from the state of vibration exerted on the apparatus (S 354  S 356 →S 355 ), normal vibration correction is carried out with the cutoff frequency of the variable HPF  1509  kept to a specified value. When only a high frequency is detected (S 354 →S 355 ) or a low frequency and high frequency are detected simultaneously (S 354 →S 356 →S 357 ), it is possible to correct vibration of the high frequency band by adaptively controlling the cutoff frequency of the variable HPF  1509  based on the detected frequency and reduce the deterioration of resolution of the sensed image caused by the high frequency component.  
         [0112]    [Second Embodiment] 
         [0113]    The first embodiment has described the case where according to the state of vibration exerted on the apparatus, when only a low frequency is detected, normal vibration correction is performed without controlling the cutoff frequency of the variable HPF  1509  and when only a high frequency is detected or when a low frequency and high frequency are detected simultaneously, the cutoff frequency of the variable HPF  1509  is controlled based on the detected frequency, thereby making it possible to correct vibration of the high frequency band. The second embodiment of the present invention is designed to perform control in such a way as to stop vibration correction control when a frequency exceeding a high frequency for which vibration correction is controllable is detected.  
         [0114]    [0114]FIG. 5 is a block diagram showing an internal configuration of a microcomputer  1505 ″ according to the second embodiment of the present invention and the other same components as those in the conventional example in FIG. 12 and the first embodiment in FIG. 1 are assigned the same reference numerals and their explanations will be omitted.  
         [0115]    In FIG. 5, reference numeral  5  denotes a vibration correction frequency/correction target value control section which decides the state of vibration from a vibration frequency of the apparatus and performs frequency control for correcting vibration or control of switching between vibration correction target values. Reference numeral  6  denotes a correction target value switching section which switches, based on the vibration detection signal, between a correction target value calculated based on the vibration detection signal and a predetermined correction target value.  
         [0116]    [0116]FIG. 6 shows a circuit configuration of the correction target value switching section  6 .  
         [0117]    In FIG. 6, the output of a first integrator  1510  is input to an a terminal of a changeover switch, while a correction target value (correction central value) is input to a b terminal of the changeover switch. Furthermore, this changeover switch supplies a control signal from the vibration correction frequency/correction target value control section  5  to the c terminal to thereby make it possible to select either the signal at the a terminal or b terminal and the selected output is output as a correction target value and input to a D/A converter  1515 .  
         [0118]    Then, the operation of the microcomputer  1505 ″ having the above configuration will be explained.  
         [0119]    As in the case of the above described first embodiment, the vibration correction frequency/correction target value control section  5  to which the frequencies detected by a first frequency detection section  1511  and second frequency detection section  10  are input operates to perform control in such a way that the cutoff frequency of the variable HPF  1509  is kept to a specified value depending on the situation of the detected frequency or shifted gradually from the specified value to the high frequency side or returned gradually from a state in which it has been shifted to the high frequency side to the specified value.  
         [0120]    However, when the high frequency vibration frequency detected by the first frequency detection section  1511  or the second frequency detection section  10  is a frequency in the frequency band  1304  shown in FIG. 16A and FIG. 16B where vibration correction is uncontrollable, even if the cutoff frequency of the variable HPF  1509  is shifted to the high frequency side through adaptive control, it is not possible to compensate for a phase delay of the high frequency band, vibration correction control is disabled and in the worst case, the phase may be inverted causing more vibration to the shift lens. As a measure to avoid such a phenomenon, the second embodiment performs control in such a way as to stop vibration correction control.  
         [0121]    More specifically, when the vibration correction frequency/correction target value control section  5  decides that the first frequency or second frequency detected by the first frequency detection section  1511  or second frequency detection section  10  exceeds a third frequency threshold (fth3) set in the vibration correction frequency/correction target value control section  5 , a control signal is output to the correction target value switching section  6 . The third frequency threshold (fth3) is a lower limit of the frequency band  1304  shown in FIG. 16A and FIG. 16B for which vibration correction is uncontrollable (f3 in FIG. 16A and FIG. 16B).  
         [0122]    When the control signal is input from the vibration correction frequency/correction target value control section  5 , the correction target value switching section  6  switches from the correction target value calculated based on the vibration detection signal by the first integrator  1510  (a terminal of the changeover switch) to a predetermined correction target value (b terminal of the changeover switch) as shown by a dotted line in FIG. 6. The predetermined correction target value is an amplitude central value of the correction target value output from the microcomputer  1505  and the shift lens  703  is held to the center of the optical axis.  
         [0123]    Next, the processing executed in the microcomputer  1505 ″ according to the second embodiment of the present invention will be explained with reference to the flow charts in FIGS. 7 and 8.  
         [0124]    [0124]FIG. 7 is a flow chart showing the vibration correction processing executed in the microcomputer  1505 ″ which is the processing of interrupting the overall processing of the microcomputer  1505 ″ at a predetermined period (e.g., 1 [ms]). The processing from steps S 301  to S 306  and processing from steps S 307  to S 311  are the same as the operation in steps in FIG. 3 explained in the above described first embodiment and their explanations will be omitted.  
         [0125]    In FIG. 7, when the operation of the first integrator  1510  in step S 306  finishes, the process moves on to step S 312 , where it is decided whether vibration correction should be performed or not according to the comparison result between the detected second frequency and a predetermined threshold (fth3) which will be described later, that is, whether vibration correction should be turned ON or OFF. If ON (YES), the process moves on to aforementioned step S 307  and the correction target value to be output is set to the angular displacement signal calculated by the first integrator  1510 . Whereas, if OFF (NO), the process moves on to step S 313 , where the correction central value is set to the correction target value to be output in step S 307  which is the subsequent operation.  
         [0126]    That is, since vibration correction is normally ON, the angular displacement signal calculated by the first integrator  1510  is output in step S 307 , but when a frequency exceeding the high frequency for which vibration correction is controllable is detected, the vibration correction control is stopped and the correction central value is set as the correction target value.  
         [0127]    Next, frequency detection, setting of a variable HPF cutoff frequency and correction target value switching processing will be explained using the flow chart in FIG. 8. The processes which overlap with the above first embodiment are assigned the same step numbers and detailed explanations thereof will be omitted.  
         [0128]    In FIG. 8, at step S 351 , frequency detection, setting of a cutoff frequency for the variable HPF and correction target value switching processing are started. First in step S 352 , the first frequency is detected and in step S 353 , the second frequency is detected. Then in next step S 354 , the first frequency detected by the first frequency detection section  1511  is compared with the first threshold (fth1) and if the first frequency is greater, the process moves on to step S 651 , where the first frequency is compared with the predetermined third threshold (fth3). If the first frequency is smaller or equal, the process moves on to step S 355 , where the cutoff frequency of the variable HPF  1509  is set based on the first frequency.  
         [0129]    Furthermore, if the first frequency is decided to be smaller or equal in step S 354 , the process moves on to step S 356 , where the second frequency detected by the second frequency detection section  10  is compared with the predetermined second threshold (fth2). If this comparison result shows that the second frequency is smaller or equal, the process moves on to step S 355 , where the cutoff frequency of the variable HPF  1509  is set based on the first frequency.  
         [0130]    Furthermore, when the second frequency is decided to be greater in step S 356 , the process moves on to step S 652 , where the second frequency is compared with the third threshold (fth3) and if the second frequency is smaller or equal, the process moves on to step S 357 , where the cutoff frequency of the variable HPF  1509  is set based on the second frequency.  
         [0131]    Furthermore, when the first frequency or second frequency is decided to be greater than the predetermined third threshold (fth3) in step S 651  or S 652 , the process moves on to step S 653 , where a correction central value is output as a predetermined correction target value as described above thereby a vibration correction value is set to OFF.  
         [0132]    Next, the operation of the vibration correction frequency/correction target value control section  5  will be explained in detail with reference to the same flow chart in FIG. 8. The processing from steps S 351  to S 353 , the first threshold (fth1) and second threshold (fth2) are the same as the aforementioned first embodiment and therefore explanations thereof will be omitted.  
         [0133]    In step S 354 , the first frequency detected by the first frequency detection section  1511  is compared with a first threshold (hereinafter simply referred to as “fth1”) and if the first frequency is higher than fth1 (YES), the detected frequency is a high frequency higher than the frequency of camera shake, and therefore the process moves on to step S 651 , where the first frequency is compared with a third threshold (hereinafter simply referred to as “fth3”). As fth3, a lower limit of a frequency band for which vibration correction is uncontrollable can be set (e.g., 30 Hz). When this comparison result shows that the first frequency is equal to or smaller than fth3 (NO), the first frequency is a high frequency for which vibration is correctable, and therefore the process moves on to step S 355 . In step S 355 , since the comparison result in step S 354  indicates that the first frequency is higher than fth1 and the comparison result in step S 651  indicates that the first frequency is equal to or lower than fth3, it is decided that the state of vibration of the apparatus is higher than the normal camera shake frequency and only a high frequency of the frequency band for which vibration correction is controllable and the vibration correction frequency/correction target value control section  5  thereby operates so as to correct vibration in the high frequency band by gradually shifting the cutoff frequency of the variable HPF  1509  from the setting at the time of normal camera shake correction to the high frequency side based on the first frequency detected by the first frequency detection section  1511 . Therefore, it is possible to improve the effect of vibration suppression of the high frequency band and reduce deterioration of resolution of a sensed image caused by vibration of the high frequency.  
         [0134]    Furthermore, when the comparison result in step S 651  indicates that the first frequency is higher than fth3 (YES), it is in the band for which vibration correction is uncontrollable, and therefore the process moves on to step S 653 , where a signal is issued to the correction target value switching section  6  so as to select a predetermined correction target value as the vibration correction target value, or more specifically, select the central value of the amplitude of the correction target value output from the first integrator  1510  (that is, to select the b terminal in FIG. 6), and vibration correction control is thereby stopped. Since the central value is set as correction target value, the shift lens is held at the center of the optical axis and vibration correction is stopped. This makes it possible to reduce the deterioration of resolution of the sensed image due to a phase delay of the high frequency band where vibration correction is uncontrollable or suppress vibration of the vibration correcting means, thus preventing disturbances in the image.  
         [0135]    Next, the case where the first frequency detected by the first frequency detection section  1511  is equals to or lower than fth1 (NO) in step S 354  will be explained.  
         [0136]    In this case, the process moves on to step S 356  as in the case of the first embodiment, where it is decided whether there is any high frequency in the second frequency detected by the second frequency detection section  10  which is capable of detecting a high frequency more than the conventional frequency detection section  1511  by comparing the second frequency with fth2. If the comparison result shows that the second frequency is equal to or lower than fth2 (NO), the process moves on to step S 355 . Since the comparison result in step S 354  indicates that the first frequency is equal to or lower than fth1 and the comparison result in step S 356  indicates that the second frequency is equal to or lower than fth2, and therefore it is decided that the vibration state of the apparatus is only a low frequency of the normal camera shake frequency band and the setting at the time of normal camera shake correction is kept as the cutoff frequency of the variable HPF  1509  based on the first frequency as described above. Therefore, normal camera shake correction is performed.  
         [0137]    Furthermore, when the second frequency is decided to be higher than fth2 (YES) in step S 356  above, this means that a high frequency has been detected, and therefore the process moves on to step S 652 , where it is decided whether the second frequency is higher than fth3 or not. If the second frequency is equal to or lower than fth3 (NO), the process moves on to step S 357 . Then in step S 357 , since the comparison result in step S 354 ,indicates that the first frequency is equal to or lower than fth1, the comparison result in step S 356  indicates that the second frequency is higher than fth2 and the comparison result in step S 652  indicates that the second frequency is equal to or lower than fth3, it is decided that the vibration state of the apparatus is a mixture of the camera shake frequency and a high frequency of the frequency for which vibration is correctable, and the vibration correction frequency/correction target value control section  5  operates so as to correct vibration of the high frequency band by gradually shifting the cutoff frequency of the variable HPF  1509  from the setting at the time of normal camera shake correction to the high frequency side based on the second frequency. Therefore, priority is given to vibration correction of the high frequency band, and therefore the effect of vibration suppression of the normal camera shake frequency band tends to reduce. However, since the effect of vibration suppression of the high frequency band improves through adaptive control, it is possible to reduce deterioration of resolution of a sensed image caused by the high frequency component.  
         [0138]    Next, the case where the vibration frequency detected by the first frequency detection section  1511  is equals to or lower than fth1 (NO) in step S 354  above, the second frequency detected by the second frequency detection section  10  is higher than fth2 (YES) in step S 356  and the comparison result in step S 652  indicates that the second frequency is higher than fth3 (YES) will be explained.  
         [0139]    In this case, since a low frequency of the camera shake frequency band is mixed with a high frequency of the band for which vibration correction is uncontrollable, the process moves on to step S 653 , where vibration correction control is stopped by issuing a signal to the correction target value switching section  6  so as to set a predetermined correction target value as the vibration correction target value or more specifically to select a central value of the amplitude of a correction target value output from the first integrator  1510  (that is, the b terminal in FIG. 6 is selected). With the correction target value set to the central value, the shift lens is held at the center of the optical axis and vibration correction is stopped. Thus, it is possible to reduce deterioration of resolution of a sensed image due to a phase delay in the high frequency band for which vibration correction is uncontrollable or suppress vibration of the vibration correcting means and thereby avoid disturbance of the sensed image.  
         [0140]    When only a low frequency is detected from the state of vibration exerted on the apparatus (S 354 →S 356 →S 355 ), normal vibration correction is carried out without controlling the cutoff frequency of the variable HPF  1509  and when only a high frequency is detected (S 354 →S 651 →S 355 ) or a low frequency and high frequency are detected simultaneously (S 354 →S 356 →S 652 →S 357 ), it is possible to correct vibration of the high frequency band by adaptively controlling the cutoff frequency of the variable HPF  1509 .  
         [0141]    Furthermore, when the high frequency detected by the first frequency detection section  1511  or second frequency detection section  10  exceeds the vibration correction control range (S 354 →S 651 →S 653  or S 354 →S 356 →S 652 →S 653 ), it is possible to stop vibration correction by setting a correction central value as the correction target value, reduce deterioration of resolution of the sensed image or suppress vibration of the vibration correcting means. That is, it is possible to avoid disturbance of the sensed image.  
         [0142]    The above described embodiments have described examples of constructing the vibration correcting means of a shift lens and driving circuit, but the present invention is not limited to this and the vibration correcting means can also be constructed of a variable apical angle prism (VAP) and its driving circuit.  
         [0143]    The present invention is not limited to the above embodiments and various changes and modifications can be made within the spirit and scope of the present invention. Therefore to apprise the public of the scope of the present invention, the following claims are made.