JP6645165B2 - Shake state determination device and imaging device - Google Patents

Description

  The present invention relates to a shake detection process performed in an image pickup apparatus with a camera shake correction function.

  Since the gyro signal includes an offset voltage and the like, when performing anti-shake control using the gyro signal, the gyro signal is used through a high-pass filter (HPF) to reduce low-frequency noise including the offset voltage. However, if large shake such as panning is detected before the start of control, correct filtering cannot be performed due to the influence of the transient response of the high-pass filter, and appropriate image stabilization control cannot be performed. Therefore, there is known a technique for resetting a high-pass filter of a gyro when panning is detected to reduce a transient response. For example, for the purpose of suppressing a transient response after occurrence of panning, a configuration is disclosed in which when the output of the high-pass filter is equal to or larger than a threshold, panning is determined to start and the high-pass filter is reset (see Patent Document 1).

JP 2007-324929 A

  In the control of Patent Literature 1, a sufficient effect cannot be obtained unless the reset of the high-pass filter is completed at an accurate timing at which the panning ends, but the timing of a change in the shake state such as the end of the panning is detected with high accuracy. It is difficult.

  An object of the present invention is to accurately detect a change in a shake state.

  A shake state determination device according to the present invention includes: a shaker that filters a shake signal to remove a predetermined frequency component; a shaker signal evaluator that performs an evaluation according to a state of an output filtered by the filterr; A determination unit configured to determine whether or not the shake state has changed.

  The shake signal evaluation unit includes a scoring unit that assigns a score to the output based on a predetermined rule, and the determination unit determines the end of panning based on the score obtained by the scoring unit. It is preferable that the shake signal evaluation means further includes a determination means for determining the start of panning based on the score obtained by the scoring means. The filtering means is, for example, a high-pass filter having a predetermined cut-off frequency for the shake signal and a low-pass filter having a predetermined cut-off frequency for the shake signal.

  The scoring unit scores, for example, the filtered output based on a table of thresholds and scores set in stages. Further, the scoring means may calculate a score for the filtered output using an N-order function.

  The scoring means includes, for example, an output of a high-pass filter having a predetermined cutoff frequency for a yaw direction shake signal, an output of a low-pass filter having a predetermined cutoff frequency for a yaw direction shake signal, and a predetermined cutoff for a pitch direction shake signal. Points are assigned to the output of the high-pass filter of the off-frequency and the output of the low-pass filter of the predetermined cutoff frequency for the shake signal in the pitch direction. Further, the scoring unit may further assign a score to the output of the high-pass filter having a predetermined cutoff frequency for the roll direction shake signal and the output of the low-pass filter having the predetermined cutoff frequency for the roll direction shake signal.

  The judging means judges that the panning has started by comparing the total score in the yaw direction and the pitch direction, the total score in the yaw direction, or the total score in the pitch direction with a predetermined threshold value. In addition, it is preferable that the shake signal evaluation means resets a high-pass filter applied to the shake signal to calculate a control target value for shake correction at a timing when it is determined that panning has been completed.

  For example, when the score in the yaw direction is equal to or more than a predetermined threshold value and the score in the pitch direction is equal to or less than a predetermined threshold value, the determination unit determines that the camera is in the panning state in the pitch direction. In addition, for example, when the score in the pitch direction is equal to or more than the threshold value and the score in the yaw direction is equal to or less than the threshold value, the determination unit determines that the panning is performed in the yaw direction.

  According to another aspect of the invention, there is provided an imaging apparatus including: the shake signal evaluation unit described above; a shake detection unit that detects a shake signal; and a shake correction unit that performs shake correction based on the shake signal.

  According to the present invention, it is possible to accurately detect a change in the shake state.

FIG. 1 is a block diagram illustrating a configuration of an imaging device according to an embodiment of the present invention. FIG. 3 is a block diagram illustrating a configuration of a sensor signal processing unit. It is a flowchart of a pan start / end detection process of the first embodiment. It is a flowchart of the score calculation processing of 1st Embodiment performed in step S201 of bread start / end detection processing. 5 illustrates a score (point) table used in the score calculation processing of FIG. 4. 4 is a flowchart of a pan start determination process executed in step S203 of FIG. 4 is a flowchart of a pan end determination process executed in step S204 of FIG. It is a flowchart of the follow shot determination processing used in the second embodiment. It is a flowchart of the bread start determination processing of 3rd Embodiment which does not use a score. It is a flow chart of bread start / end detection processing of a 4th embodiment. 11 is a flowchart of a one-axis pan start determination process for a yaw axis executed in step S903 in FIG. 10. 11 is a flowchart of a one-axis pan end determination process for a yaw axis performed in step S904 of FIG. 10. It is a flow chart of bread start / end detection processing of a 5th embodiment. It is a flowchart of the follow shot determination processing of the sixth embodiment without using a score.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of an imaging device according to an embodiment of the present invention.

  The imaging device 10 of the present embodiment is, for example, a digital camera. The digital camera 10 is provided with a CPU 18 for controlling the entire camera. ON / OFF of the power switch SWMAIN is controlled by operating a power button (not shown) provided on the surface of the digital camera 10. When the power switch SWMAIN is turned on, power is supplied from the battery 14 to the CPU 18, and the digital camera 10 operates.

  The photometric switch SWS is turned on when a shutter button (not shown) on the surface of the digital camera 10 is half-pressed. When the photometry switch SWS is turned on, the CPU 18 executes a photometry process and a distance measurement process. That is, the CPU 18 calculates an exposure value based on an input from the photometric device 11, and calculates an aperture value, a shutter speed, and an exposure time of the image sensor 20 required for photographing based on the exposure value. Here, the CPU 18 can also set the exposure time selected by the user by operating the button.

  Further, the CPU 18 calculates a driving amount of the photographing lens 16 based on an input from the distance measuring device 12 and outputs a control signal to the focus driving circuit 21. As a result, a drive signal is output from the focus drive circuit 21 to the photographing lens 16.

  The release switch SWR is turned on when the shutter button is fully pressed. When the release switch SWR is turned on, the CPU 18 calculates a drive amount of an aperture driving mechanism and a shutter (neither is shown) according to the aperture value calculated in the photometric processing. Then, a control signal is output from the CPU 18 to the aperture drive circuit 22 and the shutter drive circuit 23 based on the calculation result.

  Further, a drive signal is output from the aperture drive circuit 22 to an aperture drive mechanism (not shown), whereby the aperture drive mechanism is driven. When the aperture driving mechanism is driven, its movement is transmitted to an aperture (not shown), and the aperture diameter of the aperture is determined to a predetermined size. Further, a drive signal is output from the shutter drive circuit 23 to the shutter, whereby the shutter is opened for a predetermined time. With the above control, the light passing through the photographing lens 16 is incident on the light receiving surface of the image sensor 20.

  A control signal is output to the image sensor drive circuit 24 based on the above-described charge accumulation time, and a drive signal is output from the image sensor drive circuit 24 to the image sensor 20. The image sensor 20 photoelectrically converts the optical image of the subject formed in the light receiving area, and outputs an analog image signal. The analog image signal is converted into a digital image signal by the A / D conversion circuit 25 and input to the CPU 18.

  The digital image signal is subjected to predetermined image processing under the control of the CPU 18. The image data is temporarily stored in the DRAM 30 during the image processing. The image data subjected to the predetermined image processing is displayed on a monitor (LCD) 31 provided on the back of the camera body. The EEPROM 32 stores various programs for moving the camera. When the light amount of the subject is insufficient, a drive signal is output from the CPU to the flash circuit 33, and the flash light is supplied.

  In addition, the digital camera 10 includes a camera shake correction mechanism (shake correction means) 80. The camera shake correction mechanism 80 according to the present embodiment cancels camera shake by moving the image sensor 20, and detects, for example, a yaw angular velocity and a pitch angular velocity in a direction in which the lens of the digital camera 10 is directed by a gyro sensor. Each gyro sensor is provided in, for example, a shake detection sensor 81, and a signal (gyro signal or shake signal) from the gyro sensor such as an angular velocity signal is input to a sensor signal processing unit 82 described later, and a control target value is calculated. Then, the same value is output to the camera shake correction mechanism 80. In addition, the CPU 18 detects the start and end of panning of the camera based on a signal from the sensor signal processing unit 82 (pan start / end detection processing: described later).

  Next, the configuration of the sensor signal processing unit 82 of the first embodiment will be described with reference to FIG. In FIG. 2, signal processing from the shake detection sensor 81 for the yaw angular velocity signal is described as a representative example, but the same applies to sensor signals around other axes.

  In the sensor signal processing section 82, first, an offset value (Gyro_Yaw Offset) 102 is subtracted from a raw angular velocity signal (Gyro_YawR) 101 input from the gyro sensor of the shake detection sensor 81. The angular velocity signal (Gyro_Yaw) 103 from which the offset value has been removed is filtered (DC component cut) through a high-pass filter 104 having a cutoff frequency fc = α [Hz] in order to remove low-frequency noise. The angular velocity signal filtered by the high-pass filter 104 is multiplied by a predetermined coefficient by an amplifier 105, integrated by an integration section 106, and calculated as a control target value 107.

  Further, in the present embodiment, the angular velocity signal (Gyro_Yaw) 103 from which the offset value has been removed is also filtered through a low-pass filter (LPF) 108 with a cutoff frequency fc = β [Hz], and becomes a low-frequency component signal (Gyro_YawLPF) 109. Is calculated. Further, it is calculated as a high-frequency component signal (Gyro_YawHPF) 110 obtained by subtracting the low-frequency component signal (Gyro_YawLPF) 109 from the angular velocity signal 103 from which the offset value has been removed.

  The high-frequency component signal (Gyro_YawHPF) 110 may be calculated by using a high-pass filter different from the high-pass filter 104 with respect to the angular velocity signal (Gyro_Yaw) 103 from which the offset value has been removed. In consideration of, for example, efficiency improvement, the low-frequency component signal (Gyro_YawLPF) 109 is subtracted from the angular velocity signal (Gyro_Yaw) 103 from which the offset value has been removed to obtain a high-frequency component signal (Gyro_YawHPF) 110. The low-frequency component signal (Gyro_YawLPF) 109 and the high-frequency component signal (Gyro_YawHPF) 110 are transmitted to the CPU 18 (see FIG. 1). The cutoff frequency fc for signals around other axes such as the pitch angle may be the same as or different from that for the yaw angle, and is preferably adjusted to the response characteristic of the angular velocity signal around each axis to the panning operation. Is determined.

  Next, the pan start / end detection processing in the first embodiment will be described with reference to the flowchart of FIG.

  The pan start / end detection processing according to the first embodiment is basically executed at a predetermined sampling cycle after the camera is started and continuously until the camera is turned off. If the determination of the pan state is changed during the exposure, there is a concern that the image stabilization control cannot be performed correctly. Therefore, during the period from the start of the release process to the end of the release, the main panning start / end detection process may be prohibited.

  When the pan start / end detection process starts, in step S201, a score (point) for judging pan start / end is calculated. Next, in step S202, it is determined whether or not the current state is a panning state. If it is determined that the panning state is not present, a pan start determination process is performed in step S203, and a main pan start / end detection process is performed. Ends. On the other hand, if it is determined in step S202 that the current state is a panning state, a pan end determination is performed in step S204, and the main pan start / end detection processing ends.

  Next, the score calculation (scoring) process of the first embodiment executed in step S201 of FIG. 3 will be described with reference to the flowchart of FIG. 4 and the score (point) table of FIG. In the following description, a score calculation process using a yaw angle and a pitch angle will be described, but a score for a roll angle can also be included.

  In the present embodiment, in order to perform the pan start / end determination, a score is calculated based on the following predetermined rule. First, in the score calculation process (FIG. 3, step S201), in step S301, the low frequency component signal (Gyro_YawLPF) 109 and the high frequency component signal (Gyro_YawHPF) 110 for the yaw angle, and the yaw angle described with reference to FIG. The scores are obtained for the low frequency component signal (Gyro_PitchLPF) and the high frequency component signal (Gyro_PitchHPF) for the pitch angle calculated by the sensor signal processing unit 82 in the same manner as the signal processing.

  The scores for the signals Gyro_YawLPF, Gyro_YawHPF, Gyro_PitchLPF, and Gyro_PitchHPF are determined based on, for example, the tables 303 and 304 shown in FIG. That is, the score for the low-frequency component signal is based on the threshold value of the table 303, for example, 50 points if the absolute value ABS (LPF) of each low-frequency component signal Gyro_YawLPF and Gyro_PitchLPF passed through a low-pass filter (LPF) is 100 or less, 100 If <ABS (LPF) ≦ 150, 30 points are given; if 150 <ABS (LPF) ≦ 250, 10 points; if ABS (LPF)> 250, 0 points are given. The score for the high-frequency component signal is based on the threshold value of the table 304. For example, if the absolute value ABS (HPF) of each high-frequency component signal passed through a high-pass filter (HPF) is 50 or less, 30 points, and 50 <ABS (HPF) If ≤100, 20 points, if 100 <ABS (HPF) ≤150, 10 points, and if ABS (HPF)> 150, 0 points.

  Next, in step S302, the sum of the score YawLPF of the low frequency component signal Gyro_YawLPF based on the table 303 and the score YawHPF of the high frequency component signal Gyro_YawHPF based on the table 304 is determined as a yaw angle score Yaw, and the low frequency component signal based on the table 303 is determined. The sum of the score PitchLPF of the Gyro_PitchLPF and the score PitchHPF of the high-frequency component signal Gyro_PitchHPF based on the table 304 is determined as the pitch Pitch of the pitch angle. Then, the sum of the score Yaw and the score Ptich is defined as a score YP. In the present embodiment, the calculation is performed such that the closer the holding state of the camera is to the stable state, the higher the score is.

  FIG. 6 is a flowchart of the pan start determination process executed in step S203 of FIG. With reference to FIG. 6, the bread start determination processing according to the present embodiment will be described.

  In the pan start determination processing, first, in step S401, the value of the score YP is checked using the first threshold value. If it is determined that the score YP is equal to or less than the first threshold, the process proceeds to step S403, and the pan start counter is incremented. On the other hand, if it is determined in step S401 that the score YP is larger than the first threshold, it is determined in step S402 whether the score Yaw is equal to or smaller than the second threshold or the score Pitch is equal to or smaller than the second threshold. If any of the scores Yaw and Pitch is equal to or less than the second threshold, the process proceeds to step S403, and the pan start counter is incremented. On the other hand, if it is determined in step S402 that both the score Yaw and the score Pitch are greater than the second threshold, the pan start counter is reset in step S406 in preparation for the next pan start determination, and the main pan start determination processing ends. .

  When the pan start counter is incremented in step S403, it is determined in step S404 whether the pan start counter is equal to or greater than a third threshold. If it is determined that the pan start counter is equal to or greater than the third threshold value, the state of the camera is changed to a pan state in step S405, and the pan start counter is reset in preparation for the next pan start determination. The start determination processing ends. On the other hand, when it is determined in step S404 that the pan start counter is smaller than the third threshold value, the main pan start determination processing ends immediately.

  FIG. 7 is a flowchart of the pan end determination process executed in step S204 of FIG. With reference to FIG. 7, a description will be given of the pan end determination processing of the present embodiment.

  In the pan end determination processing, first, in step S501, it is determined whether or not the score YP is equal to or greater than a fourth threshold. If the score YP is equal to or larger than the fourth threshold value, the pan end counter is incremented in step S502. On the other hand, if it is determined that the score YP is smaller than the fourth threshold value, the pan end counter is reset in step S503, and the main pan end determination processing ends.

  When the pan end counter is incremented in step S502, it is determined in step S504 whether the pan end counter is equal to or greater than a fifth threshold. If it is determined that the value is equal to or larger than the fifth threshold value, in step S505, it is determined that the pan has ended, the state determination of the camera is changed to the stable state, and the pan end counter is reset in preparation for the next pan end determination. . In addition, since it can be determined that the timing is appropriate for resetting the high-pass filter (HPF) 104 in FIG. 2, the high-pass filter 104 is reset in step S506, and the main pan end determination processing ends. When it is determined in step S504 that the pan end counter is equal to or smaller than the fifth threshold value, the main pan end determination process ends immediately.

  In addition, although the shake signal around the yaw angle and the pitch angle is used for the determination of the pan start / end, the shake signal around the roll angle may be added to perform the determination based on the shake signal around the three axes. Good.

  As described above, in the first embodiment, the end of panning can be detected with high accuracy by dividing the shake signal into low-frequency components and high-frequency components and converting the score into scores. The filter can be reset accurately at the end of the panning, and the image stabilization accuracy is improved. Also, by making a score for signals around a plurality of axes and using these scores in combination, it is possible to more accurately grasp the condition and perform more appropriate processing. Further, in the present embodiment, the timing of starting panning is also determined from the score, so that the timing of starting panning can be determined more accurately.

  In the first embodiment, the score calculation described with reference to FIGS. 4 and 5 may be performed by another method. For example, in FIGS. 4 and 5, scores are assigned stepwise according to the magnitudes of the absolute values of the low frequency component and the high frequency component of the gyro signal with respect to each axis. The score can also be obtained by using a predetermined function such as an n-order function using the absolute value X of the component as a variable.

For example, assuming that the absolute value of the low-frequency component signal Gyro_YawLPF related to the yaw angle is X, the score YawLPF for the low-frequency component signal related to the yaw angle is a, b, and c as coefficients of a quadratic function.
YawLPF = aX ² + bX + c
Asking. However, when X is equal to or larger than a predetermined threshold, the score may be set to 0. Similarly, at this time, the absolute value of the yaw angle high frequency component signal Gyro_YawHPF is X, the score YawHPF for the yaw angle high frequency component signal is d, e, and f are the coefficients of the quadratic function.
YawHPF = dX ² + eX + f
Asking.

  Similarly, quadratic functions are similarly defined for the absolute values of the low frequency component signal Gyro_PitchLPF and the high frequency component signal Gyro_PitchHPF relating to the pitch angle, and the respective scores PitchLPF and PitchHPF are obtained. As in the embodiment, the yaw angle and pitch angle scores Yaw and Pitch are Yaw = YawLPF + YawHPF and Pitch = PitchLPF + PitchHPF. As for the score Yp, the score Yp = score Yaw + score as in the embodiment. Ask as Pitch.

  In the panning determination described below, not the sum of the score of the low-frequency component signal and the score of the high-frequency component, there is a possibility that the difference may be determined with higher accuracy by using the difference, the score Yaw2, As Pitch2, the difference between score YawLPF and score YawHPF (YawLPF-YawHPF) and / or the difference between score PitchLPF and score PitchHPF (PitchLPF-PitchHPF) can also be calculated.

  Next, a second embodiment including a panning determination process will be described with reference to the flowchart in FIG. Note that the second embodiment is the same as the first embodiment except that a panning determination process is provided.

  A situation in which the camera shakes greatly and a large shake signal (gyro signal) is detected includes a panning shot in which the camera is moved in one direction at a constant speed following the subject. In panning, for example, when the camera is moved only in the yaw direction, it is preferable to perform image stabilization control in the pitch direction. Therefore, when it is determined that the camera is moved only in one direction of yaw or pitch, it is desirable to determine that the camera is panning and to perform control in accordance with the panning. This panning shooting detection processing is performed, for example, in parallel with the pan start / end detection processing of FIG. 3 described in the first embodiment.

  When the panning determination process according to the present embodiment is started, first, in step S701, it is determined whether the score Yaw is equal to or less than a sixth threshold. Note that, instead of the score Yaw, the above-described score Yaw2 with a different threshold value may be used for the determination in step S701.

  If it is determined in step S701 that the score Yaw is equal to or smaller than the sixth threshold, in step S702, the pan start counter YawC for the yaw direction is incremented. On the other hand, if it is determined in step S701 that the score Yaw is larger than the sixth threshold, the pan start counter YawC in the yaw direction is reset in step S703.

  When the pan start counter YawC in the yaw direction is operated in step S702 or step S703, it is determined in step S704 whether or not the score Pitch is equal to or less than a seventh threshold. Note that, in the same determination, similarly to step S701, the above-described score Pitch2 can be used by changing the threshold value.

  If it is determined in step S704 that the value is equal to or smaller than the seventh threshold value, the pan start counter PitchC is incremented in step S705. On the other hand, if it is determined in step S704 that the value is larger than the seventh threshold value, the pan start counter PitchC is reset in step S706. In step S705 or step S706, when the pan start counter PitchC in the pitch direction is operated, in step S707, it is determined whether the pan start counter PitchC is equal to or less than the eighth threshold and the pan detection counter YawC is equal to or greater than the ninth threshold. Is determined.

  If it is determined in step S707 that the pan start counter PitchC is equal to or smaller than the eighth threshold and the pan detection counter YawC is not equal to or larger than the ninth threshold, in step S709, the pan start counter YawC is equal to or smaller than the eighth threshold and It is determined whether the start counter PitchC is equal to or greater than a ninth threshold.

  On the other hand, if it is determined in step S707 that the pan start counter PitchC is equal to or less than the eighth threshold and the pan detection counter YawC is equal to or greater than the ninth threshold, it can be determined that the panning is performed in the yaw direction. The camera state determination is changed to the panning shooting state in the yaw direction, and then the determination in step S709 is executed.

  If it is determined in step S709 that the pan start counter YawC is equal to or smaller than the eighth threshold and the pan start counter PitchC is equal to or larger than the ninth threshold, it can be determined that the panning is performed in the pitch direction. Is changed to the panning state in the pitch direction, and the main panning determination processing ends. On the other hand, in step S709, when it is determined that the pan start counter YawC is equal to or smaller than the eighth threshold and the pan start counter PitchC is equal to or larger than the ninth threshold, the main shot shooting determination processing is immediately terminated. It should be noted that the camera shake correction mechanism 80 (see FIG. 1) performs only shake correction in a direction perpendicular to the direction determined as the panning shooting direction, in accordance with the determination of the panning shooting state in the yaw direction and the pitch direction.

  As described above, in the configuration of the second embodiment, substantially the same effects as those of the first embodiment can be obtained, and the presence or absence of the panning in the yaw direction or the pitch direction can be determined. Shake correction can be performed in a direction that does not correspond to the shooting direction, and shake correction processing more suitable for the situation can be performed.

  Next, a third embodiment in which a score is not used for the pan start determination will be described with reference to the flowchart of FIG. The third embodiment is the same as the first embodiment, except that no score is used for the determination of the start of bread.

  In the third embodiment, the pan start determination is not based on the score, but rather on the angular velocity signal (Gyro_Yaw, Gyro_Pitch) 103 after offset removal (see FIG. 2), the angular velocity signal passed through the high-pass filter 104, and the low-frequency component signal (Gyro_YawLPF, Gyro_PitchLPF) 109 and high-frequency component signals (Gyro_YawHPF, Gyro_PitchHPF) 110 are determined.

  In the pan start determination processing according to the third embodiment, first, in step S801, the value of the angular velocity signal Gyro_Yaw after offset removal is checked. If it is determined that the angular velocity signal Gyro_Yaw is equal to or less than the tenth threshold value, the process proceeds to processing step S803, and the pan start counter is incremented. On the other hand, if it is determined in step S801 that the angular velocity signal Gyro_Yaw is greater than the tenth threshold, it is determined in step S802 whether the angular velocity signal Gyro_Pitch after offset removal is equal to or less than the tenth threshold. If the angular velocity signal Gyro_Pitch is equal to or smaller than the tenth threshold, the process proceeds to step S803, and the pan start counter is incremented. On the other hand, if it is determined in step S802 that the angular velocity signal Gyro_Pitch is smaller than the tenth threshold value, the pan start counter is reset in preparation for the next pan start determination, and the main pan start determination processing ends.

  When the pan start counter is incremented in step S803, it is determined in step S805 whether the pan start counter is equal to or larger than the eleventh threshold. If it is determined that the pan start counter is equal to or greater than the eleventh threshold value, the state of the camera is changed to a pan state in step S806, and the pan start counter is reset in preparation for the next pan start determination. The start determination processing ends. On the other hand, when it is determined in step S805 that the pan start counter is smaller than the eleventh threshold value, the main pan start determination processing ends immediately.

  As described above, even in the third embodiment in which a score is not used to determine the start of panning, the timing for resetting the high-pass filter 104, that is, the accurate timing for ending panning can be appropriately determined. In the above description, the pan start is determined with reference to the values of the angular velocity signals Gyro_Yaw and Gyro_Pitch after offset removal. Instead, the angular velocity signal passed through the high-pass filter 104 and the low-frequency component signal (Gyro_YawLPF) are used. , Gyro_PitchLPF) 109 and high-frequency component signals (Gyro_YawHPF, Gyro_PitchHPF) 110 may be used.

  Next, an imaging device according to a fourth embodiment will be described with reference to the flowcharts in FIGS. In the fourth embodiment, the pan generation state / stable state is separately determined for each of the yaw direction and the pitch direction. The other configuration is the same as that of the first embodiment, and a description thereof will be omitted.

  FIG. 10 is a flowchart of the pan start / end detection processing of the fourth embodiment corresponding to the flowchart of FIG. 3 of the first embodiment. Similar to the pan start / end detection process of the first embodiment, the pan start / end detection process of the fourth embodiment is executed at a predetermined sampling cycle after the camera is started until the camera is turned off. You. Further, if the determination of the pan state is changed during the exposure, there is a concern that the image stabilization control cannot be performed properly. Therefore, during the period from the start of the release process to the end of the release, the start / end of the main panning is detected. The processing may be prohibited.

  When the pan start / end detection process starts, in step S901, a score for judging pan start / end is calculated. Next, in step S902, it is determined whether or not the current state is a panning state in the yaw direction. If it is determined in step S902 that the current state is not a panning state in the yaw direction, a pan start determination in the yaw direction is performed in step S903. On the other hand, if it is determined that the current state is a panning state in the yaw direction, a pan end determination in the yaw direction is performed in step S904.

  If any of the pan start / end determinations in the yaw direction is performed in steps S903 and S904, it is determined in step S905 whether the current state is a panning state in the pitch direction. If it is determined in step S905 that the current state is not a panning state in the pitch direction, a pan start determination is performed in the pitch direction in step S906. On the other hand, if it is determined in step S905 that the current state is a panning state in the pitch direction, pan end determination in the pitch direction is performed in step S907.

  If any of the pan start / end determinations in the pitch direction is performed in steps S906 and S907, it is determined in step S908 whether any of the yaw direction and the pitch direction is in a panning state. If panning is occurring in one of the yaw and pitch axes, the pan end determination process (FIG. 3, step S204) shown in FIG. 7 is executed in step S909.

  If it is determined in the pan end determination process in step S909 that the camera is in a stable state, the camera state determination is changed to a stable state with respect to the yaw axis and the pitch axis. Also, in preparation for the next pan end determination, the pan end counter is reset, the high-pass filters (HPF) 104 for the yaw angular velocity signal and the pitch angular velocity signal are reset, and the main pan start / end detection processing ends. Note that if the axis is originally in a stable state, the high-pass filter 104 related to the axis is not reset. However, if a panning state occurs, the high-pass filter 104 related to the axis is reset.

  On the other hand, if it is determined in step S908 that the pan has not occurred in any of the yaw and pitch directions, the main pan start / end detection processing ends immediately. In this embodiment, the pan start and the pan end are determined for each of the axes (the yaw axis and the pitch axis). However, it is preferable to perform the stability detection in consideration of both axes shown in FIG. .

  FIG. 11 is a flowchart of the one-axis pan start determination process for the yaw axis executed in step S903 of FIG. 10. FIG. 12 is a flowchart of the one-axis pan operation for the yaw axis executed in step S904 of FIG. It is a flowchart of an end determination process. Here, the processing for the yaw axis is shown as a representative example, but the same applies to the processing for the pitch axis.

  In the pan start determination process for one axis in FIG. 11, first, in step S1001, the value of the score Yaw is checked using the twelfth threshold. If it is determined that the score Yaw is equal to or smaller than the twelfth threshold, the process proceeds to step S1002, and the pan start counter YawC is incremented. On the other hand, if it is determined in step S1001 that the score Yaw is larger than the twelfth threshold, in step S1003, the pan start counter YawC for the yaw axis is reset in preparation for the next pan start determination, and the main pan start determination process ends. I do.

  When the pan start counter YawC is incremented in step S1002, it is determined in step S1004 whether the pan start counter YawC for the yaw direction is equal to or greater than a thirteenth threshold. If it is determined that the pan start counter YawC is equal to or larger than the thirteenth threshold, the state determination regarding the yaw direction of the camera is changed to a pan occurrence state in step S1005, and panning in the yaw direction is started in preparation for the next pan start determination. The counter YawC is reset, and the main bread start determination processing ends.

  In the one-axis pan end determination process in FIG. 12, first, in step S1101, it is determined whether the score Yaw is equal to or greater than a fourteenth threshold. If the score Yaw is equal to or larger than the fourteenth threshold, the pan end counter YawC is incremented in step S1102. On the other hand, if it is determined that the score Yaw is smaller than the fourteenth threshold, the pan end counter YawC in the yaw direction is reset in step S1103, and the main pan end determination processing ends.

  When the pan end counter YawC is incremented in step S1102, it is determined in step S1104 whether the pan end counter YawC is equal to or greater than a fifteenth threshold. If it is determined that the difference is equal to or larger than the fifteenth threshold, in step S1105, it is determined that the panning in the yaw direction has been completed, and the state determination regarding the yaw direction of the camera is changed to the stable state. Reset the pan end counter. In addition, since it can be determined that the timing is appropriate for resetting the high-pass filter, the high-pass filter (HPF) 104 in FIG. 2 is reset in step S1106, and the main pan end determination process ends. If it is determined in step S1104 that the pan end counter is equal to or smaller than the fifteenth threshold value, the main pan end determination process ends immediately.

  As described above, in the fourth embodiment, substantially the same effects as in the first embodiment can be obtained.

  Next, a pan start / end detection process according to a fifth embodiment of the present invention will be described with reference to the flowchart in FIG. The fifth embodiment corresponds to a modification of the first embodiment in which the pan start / end detection processing shown in FIG. 3 is changed, and separately determines the pan generation state / stable state in each of the yaw direction and the pitch direction. At the same time, the panning determination process is performed. The other configuration is the same as that of the first embodiment, and a description thereof will be omitted.

  When the pan start / end detection processing of the fifth embodiment is started, a score is calculated in step S1201, and subsequently, in step S1202, the state of the camera in the yaw direction is determined. If it is determined in step S1202 that the state in the yaw direction is the stable state, then in step S1203, pan start determination in the yaw direction is performed, and in step S1204, panning determination in the yaw direction is performed. It shifts to pitch determination of. If it is determined in step S1203 that panning has started, step S1204 may be skipped and the process may jump to step S1209.

  When it is determined in step S1202 that the state in the yaw direction is the panning state, in step S1205, a pan start determination in the yaw direction is performed, and in step S1206, a pan end determination is performed. Move to judgment. Note that the pan end determination determines whether the camera is stable. Therefore, it is preferable to determine whether the camera has become stable even in the panning state. If it is determined in step S1205 that panning has started, step S1206 may be skipped and the process may jump to step S1209.

  If it is determined in step S1202 that the state in the yaw direction is the panning state, panning determination is performed in step S1207, and pan end determination is performed in step S1208, and then the pitch determination in step S1209 is performed. And migrate. If it is determined in step S1207 that panning is to be performed, step S1208 may be skipped and the process may jump to step S1209.

  In the pitch (Pitch) determination in step S1209, the same processing as in steps S1202 to S1208 is performed in the pitch direction. When the processing in step S1209 ends, in step S1210, as in step S908 in FIG. 10 of the fourth embodiment, whether or not there is an axis that is not in a stable state, that is, whether or not there is an axis that is panning or panning It is determined whether or not. If there is an axis that is not in a stable state, in step S1211, the pan end determination process illustrated in FIG. 7 is performed, and then the pan start / end detection process ends. On the other hand, if it is determined in step S1210 that there is no panning state or panning state in any of the yaw and pitch directions, the main pan start / end detection processing is immediately terminated.

  As in the pan start / end detection processing in FIG. 10, if it is determined in step S1211 that the camera is in a stable state, the camera state determination is changed to a stable state with respect to the yaw axis and the pitch axis. Also, in preparation for the next pan end determination, the pan end counter is reset, the high-pass filters (HPF) 104 for the yaw angular velocity signal and the pitch angular velocity signal are reset, and the main pan start / end detection processing ends. If the axis is originally in a stable state, the high-pass filter 104 related to the axis is not reset. However, if the panning state or the panning state is set, the high-pass filter 104 related to the axis is reset.

  As described above, also in the fifth embodiment, the same effects as in the first and fourth embodiments can be obtained.

  Next, a panning determination process according to the sixth embodiment that does not use a score will be described with reference to the flowchart in FIG. In the present embodiment, the panning determination is performed for each axis without using the score. Here, a case where panning determination is performed in the yaw direction will be described as an example. Note that other configurations are the same as those of the first embodiment, and description thereof will be omitted.

  When the panning determination process according to the sixth embodiment is started, in step S1301, it is determined whether the absolute value of the angular velocity signal (Gyro_Yaw) 103 (see FIG. 2) is equal to or greater than a sixteenth threshold. If it is determined in step S1301 that the angular velocity signal (Gyro_Yaw) is equal to or larger than the sixteenth threshold, the process proceeds to step S1302. If it is determined that the angular velocity signal is equal to or smaller than the sixteenth threshold, in step S1304, the panning counter YawC2 is reset to perform main panning determination. To end.

  In step S1302, it is determined whether the state in the yaw direction is the pan state. In the case of the panning state, it is determined in step S1303 whether the absolute value of the angular velocity signal (Gyro_Yaw) is equal to or less than a seventeenth threshold. When it is determined that the absolute value of the angular velocity signal (Gyro_Yaw) is larger than the seventeenth threshold value, the panning state in the yaw direction is continued, and the panning counter YawC2 is reset in step S1304. Then, the main shot shooting determination process ends.

  On the other hand, if it is determined in step S1303 that the absolute value of the angular velocity signal (Gyro_Yaw) is equal to or smaller than the seventeenth threshold, or if it is determined in step S1302 that the camera is not in the panning state, the panning counter YawC2 is incremented in step S1305. Is done. Thereafter, in step S1306, it is determined whether or not the panning counter YawC2 is equal to or larger than the eighteenth threshold. If the panning counter YawC2 is equal to or larger than the eighteenth threshold value, in step S1307, the state of the camera in the yaw direction is changed to the panning state, and the counter is reset to prepare for the next panning detection. The determination processing ends. On the other hand, if the panning counter YawC2 is equal to or larger than the eighteenth threshold value in step S1306, the main panning determination process is immediately terminated.

  In addition, instead of the angular velocity signals (Gyro_Yaw, Gyro_Pitch) and the like, the angular velocity signals passed through the high-pass filter 104, the low-frequency component signals (Gyro_YawLPF, Gyro_PitchLPF) 109, and the high-frequency component signals (Gyro_YawHPF, Gyro_PitchHPF) 110 are shot in each axis. It may be used for determination.

  As described above, also in the configuration of the sixth embodiment, the same effect as that of the first embodiment can be obtained, and the panning state in each axial direction can be detected, so that more appropriate shake correction control can be performed. .

  Note that, in the present embodiment, an example of a camera shake correction mechanism of a type in which the image sensor is moved has been described, but another type of camera shake correction mechanism such as a lens shift method may be used. Further, in the camera shake correction of the present embodiment, the yaw angular velocity and the pitch angular velocity are detected, but the present invention is not particularly limited to these two axes. In addition, a configuration that detects the roll angular velocity may be used. For special applications, a configuration corresponding to the angular velocity in only one axial direction may be used. Further, the configuration of the imaging device according to the present invention can be applied to a smartphone, a mobile phone, and the like. Further, the change in the shake state is not limited to the change corresponding to the end of panning.

  In addition, the configurations described in each of the above-described embodiments and modified examples can be implemented by changing the combinations within a matching range.

10 Digital camera 18 CPU
80 camera shake correction mechanism 81 shake detection sensor 82 sensor signal processing unit

Claims (10)

Filtering means for cutting a predetermined frequency component from the shake signal;
Shake signal evaluation means for performing an evaluation according to the state of the output filtered by the filtering means,
Determining means for determining the presence or absence of a change in the shake state based on the evaluation ,
The shake signal evaluation means includes a scoring means for scoring the output based on a rule that gives a higher score as the shake is smaller, and the judgment means judges that a predetermined sum of the scores obtained by the scoring means is a predetermined threshold value. The pan end counter is incremented at the time above, and it is determined that the panning has ended when the value of the pan end counter is equal to or more than a predetermined threshold value,
The scoring means includes an output of a high-pass filter having a predetermined cutoff frequency for the yaw direction shake signal, an output of a low-pass filter having a predetermined cutoff frequency for the yaw direction shake signal, and a predetermined cut for the pitch direction shake signal. A shake state determination device , wherein the output of a high-pass filter having an off-frequency and the output of a low-pass filter having a predetermined cutoff frequency with respect to a shake signal in a pitch direction are scored . Filtering means for cutting a predetermined frequency component from the shake signal;
Shake signal evaluation means for performing an evaluation according to the state of the output filtered by the filtering means,
Determining means for determining the presence or absence of a change in the shake state based on the evaluation,
The shake signal evaluation means includes a scoring means for scoring the output based on a rule that gives a higher score as the shake is smaller, and the determination means determines a predetermined sum of the scores obtained by the scoring means. When the pan end counter is incremented at or above a predetermined threshold, it is determined that panning has ended when the value of the pan end counter is at least a predetermined threshold,
The scoring means calculates a score for the filtered output using an Nth-order function, and the scoring means outputs an output of a high-pass filter having a predetermined cut-off frequency for a roll direction swing signal, The output of a low-pass filter with a predetermined cutoff frequency for the shake signal
A shake state determination device, characterized in that: The shake state determination device according to claim 1 or 2, further comprising a determination unit configured to determine a start of panning based on the score obtained by the scoring unit. The determining means increments the pan start counter when the total of the scores obtained by the scoring means is equal to or less than a predetermined threshold, and determines the start of panning when the value of the pan start counter is equal to or more than a predetermined threshold. The shake state determination device according to claim 3, wherein: 5. The shake state determination according to claim 1 , wherein the scoring unit performs scoring on the filtered output based on a table of thresholds and scores set in a stepwise manner. 6. apparatus. Said predetermined sum is the sum of the yaw direction, the pitch direction number, or the sum of the yaw direction of count, or any one of claims 1-5, characterized in that it comprises the sum of the pitch direction scores 3. The shake state determination device according to claim 1. At the timing it is judged that the panning completion, the any one of claims 1 to 6, characterized in that resetting the high-pass filter to be applied to the vibration signal to calculate a control target value for the shake correction The shake state determination device according to the above. The determining means further yaw direction score is above a predetermined threshold value, when the number of the pitch direction is less than a predetermined threshold value, according to claim 1 or claim, characterized in that it is determined that a state panning the pitch direction Item 7. The shake state determination device according to Item 6 . The determining means further Pitch number is more than the threshold value, when the yaw direction of the points is equal to or lower than a threshold, according to claim 1 or claim, characterized in that it is determined that a state panning against the yaw direction 6 3. The shake state determination device according to claim 1. A shake state determination device according to any one of claims 1 to 9 ,
Shake detection means for detecting the shake signal,
And a shake correction unit that performs shake correction based on the shake signal.

Images