JP2012078495A - Imaging device, shake correction device, and shake correction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct image shake when imaging a swing.SOLUTION: The image shake correction is performed by determining whether a digital camera 1 is under a constant angular velocity motion based on an output signal of a gyro-sensor 100x (steps S4 and S5), calculating a correction amount based on a signal before subjecting to high pass filter processing, if the digital camera 1 is under the constant angular velocity motion, and driving a correction lens 41 based on the calculated correction amount (step S6), and calculating a correction amount based on a signal after subjected to the high pass filter processing, if the digital camera 1 is not under the constant angular velocity motion, and driving a correction lens 41 based on the calculated correction amount (step S7).

Description

  The present invention relates to an image pickup apparatus, a shake correction apparatus, and a shake correction method, and more particularly to a technique for correcting image shake during swing shooting.

  2. Description of the Related Art An imaging device having a camera shake correction function that corrects image blur of a captured image due to vibration such as camera shake is known. The camera shake correction function detects image blur using an angular velocity sensor or the like, and moves image components such as an imaging lens or an image sensor in the direction to correct image blur based on the detected information. Correct.

  An imaging device that can capture a panoramic image is also known. In this method, a plurality of images are photographed while swinging the imaging device in a fixed direction, and a single panoramic image is generated by combining the plurality of images.

  Patent Document 1 discloses a panoramic image composition method in which a video camera is fixed on a tripod or the like and continuously photographed, and slit images cut out in a slit shape are combined from the continuously photographed images to compose a panoramic image. Has been.

JP-A-11-164325

  In such a panoramic image imaging apparatus, since an image is taken while swinging, image blur may occur in the swing direction depending on the swing speed, shutter speed, distance to the subject, and the like. Therefore, in order to correct the image blur in the swing direction, it is conceivable to use the above-described camera shake correction function. However, when the above-described camera shake correction function is applied to the panoramic image imaging apparatus, there are the following problems.

  That is, when panoramic shooting is performed, an image is shot while the imaging apparatus is swung in a certain direction. Therefore, the main component of blurring at the time of swing is based on a substantially constant angular velocity such as an equiangular velocity output.

  However, each speed sensor or the like used for the camera shake correction function is generally provided with a high-pass filter in order to remove a drift component superimposed on its output. By this high-pass filter, a signal having no time change such as a constant angular velocity motion is removed together with a drift component.

  As described above, with the conventional camera shake correction function, it is difficult to detect the shake during the swing, and it is difficult to correct the swing direction.

  SUMMARY An advantage of some aspects of the invention is that it provides an image pickup apparatus, a shake correction apparatus, and a shake correction method that can correct image blur during swing shooting.

  In order to achieve the object, the shake correction apparatus according to claim 1 is a shake correction apparatus that corrects a subject image blur of an imaging apparatus that converts a received subject image into an image signal by an imaging unit, and the imaging apparatus A sensor that outputs a blur signal corresponding to the blur of the camera, a high-pass filter that performs a high-pass filter process on the blur signal output from the sensor, and removes and outputs a drift component superimposed on the blur signal, and the high-pass filter process Based on a later blur signal, blur correction means for optically correcting subject image blur due to the blur, and whether or not the imaging device is in a constant angular velocity motion state based on the blur signal before the high-pass filter processing A constant angular velocity movement detecting means, and the blur correction means is configured to detect a constant angular velocity movement direction when the imaging device is in a constant angular velocity movement state. For the subject image blur and correcting on the basis of the shake signal before the high-pass filtering.

  According to the first aspect of the invention, the high-pass filter process is performed on the blur signal corresponding to the blur of the imaging device, and the subject image blur due to the blur is optically corrected based on the blur signal after the high-pass filter process. Detecting whether or not the imaging device is in a constant angular velocity motion state based on the blur signal before the high-pass filter processing, and if the imaging device is in a constant angular velocity motion state, Since correction is performed based on the blur signal before the high-pass filter processing, it is possible to correct image blur at the time of swing shooting in which the imaging apparatus is in a constant angular velocity motion state.

  According to a second aspect of the present invention, in the shake correction device according to the first aspect, the sensor outputs a shake signal in a pan direction and a tilt direction of the imaging device, and the shake correction unit is an object image caused by the shake. The blur is optically corrected in each of the pan direction and the tilt direction, and the constant angular velocity motion detecting means detects whether the constant angular velocity motion direction is the pan direction or the tilt direction based on the blur signal before the high-pass filter processing. It is characterized by doing.

  Thereby, it is possible to detect whether the direction of the constant angular velocity motion is the pan direction or the tilt direction, and to correct the subject image blur in the detected direction based on the blur signal before the high-pass filter processing.

  3. The blur correction device according to claim 1, wherein the blur correction unit is driven in a plane perpendicular to the optical axis so as to be able to correct blur of the optical axis generated in the imaging unit. Correction mechanism, position control means for controlling the position of the correction mechanism based on the integrated value of the blur signal after the high-pass filter processing, and the speed of the correction mechanism based on the blur signal before the high-pass filter processing. Speed control means for controlling, and when the imaging apparatus is in a constant angular velocity motion state, subject image blurring in a uniform angular velocity motion direction is corrected by the speed control means.

  As a result, the influence of erroneous correction due to drift can be reduced, and low-frequency blur can be corrected.

  According to a fourth aspect of the present invention, in the blur correction device according to any one of the first to third aspects, the sensor outputs a blur signal corresponding to an angular blur and a parallel blur, and the blur correction unit is configured to output the angular blur. And subject image blur due to parallel blur is optically corrected, and correction of subject image blur due to parallel blur is stopped for the constant angular velocity motion direction when the imaging device is in a constant angular velocity motion state. .

  Thereby, the correction possible range of the shake correcting means can be secured.

  5. The blur correction device according to claim 1, wherein the constant angular velocity motion detecting means has a blur signal before the high-pass filter processing that is equal to or greater than a predetermined value and a differential value thereof. It is characterized in that it is detected whether or not the imaging device is in a constant angular velocity motion state when is approximately zero.

  Thereby, it is possible to appropriately detect whether or not the imaging apparatus is in a constant angular velocity motion state.

  6. The blur correction device according to claim 1, wherein the constant angular velocity motion detecting means is configured such that the absolute value of the differential value of the blur signal after the high-pass filter processing continues for a predetermined time or longer. When the value is equal to or greater than the threshold value, whether or not the imaging device is in a constant angular velocity motion state is detected based on the blur signal before the high-pass filter processing.

  Thereby, it is possible to appropriately detect whether or not the imaging apparatus is in a constant angular velocity motion state.

  In order to achieve the above object, the imaging apparatus according to claim 7 is an imaging apparatus that performs continuous shooting by swinging the apparatus body in a certain direction, an imaging unit that converts a received subject image into an image signal, and the imaging A sensor that outputs a shake signal corresponding to the shake of the apparatus, a high-pass filter that performs a high-pass filter process on the shake signal output from the sensor, removes a superimposed drift component, and outputs a shake signal after the high-pass filter process. Based on the signal, a blur correction unit that optically corrects the subject image blur due to the blur and a blur signal before the high-pass filter processing detect whether the imaging device is in a constant angular velocity motion state. A constant angular velocity motion detecting means, and the blur correction means detects a subject in the direction of the constant angular velocity motion when the constant angular velocity motion state of the imaging device is detected. For blur and correcting on the basis of the shake signal before the high-pass filtering.

  According to the seventh aspect of the invention, the high-pass filter process is performed on the blur signal corresponding to the blur of the imaging device, and the subject image blur due to the blur is optically corrected based on the blur signal after the high-pass filter process. Detecting whether or not the imaging device is in a constant angular velocity motion state based on the blur signal before the high-pass filter processing, and if the imaging device is in a constant angular velocity motion state, Since correction is performed based on the blur signal before the high-pass filter processing, it is possible to correct image blur at the time of swing shooting in which the imaging apparatus is in a constant angular velocity motion state.

  The imaging apparatus according to claim 7, wherein the imaging apparatus includes a composite panorama image shooting mode, and when the composite panorama image shooting mode is set, the continuously shot images are combined. And image synthesizing means for generating a panoramic image.

  9. The image pickup apparatus according to claim 8, wherein the image synthesizing unit starts image synthesis when it is detected that the image pickup apparatus is in a constant angular velocity motion state. .

  The imaging apparatus according to any one of claims 7 to 9, wherein the blur correction unit detects the subject in the direction of the constant angular velocity motion when the imaging device is detected to be in a uniform angular velocity motion state. Image blur correction is started.

  In order to achieve the object, the blur correction method according to claim 11 is a blur correction method for correcting subject image blur of an imaging device that converts a received subject image into an image signal by an imaging unit, and the imaging device. A blur signal acquisition step of acquiring a blur signal corresponding to the blur of the sensor from the sensor, a high-pass filter processing step of removing and outputting a drift component superimposed on the acquired blur signal, and a blur signal after the high-pass filter processing step Based on this, a correction mechanism that is driven in a plane perpendicular to the optical axis of the image pickup means is driven to optically correct a subject image blur due to the blur, and a blur correction step before the high-pass filter processing step. And a constant angular velocity motion detecting step of detecting whether the imaging device is in a constant angular velocity motion state based on a signal, wherein the blur correction step includes the imaging Location is in the case of constant angular velocity motion state, for constant angular velocity motion direction of the subject image blur and correcting by driving the correcting mechanism on the basis of the shake signal before the high-pass filtering process.

  According to the eleventh aspect of the present invention, the high-pass filter process is performed on the blur signal corresponding to the blur of the imaging device, and the subject image blur due to the blur is optically corrected based on the blur signal after the high-pass filter process. Detecting whether or not the imaging device is in a constant angular velocity motion state based on the blur signal before the high-pass filter processing, and if the imaging device is in a constant angular velocity motion state, Since correction is performed based on the blur signal before the high-pass filter processing, it is possible to correct image blur at the time of swing shooting in which the imaging apparatus is in a constant angular velocity motion state.

  According to the present invention, it is possible to correct image blur at the time of swing shooting in which the imaging apparatus is in a constant angular velocity motion state.

1 is a block diagram showing an electrical configuration of a digital camera 1 according to a first embodiment. The figure which showed the optical system of digital camera 1 The block diagram which shows the internal structure of the shake correction apparatus of the swing direction of 1st Embodiment. Diagram comparing signal characteristics before and after high-pass filtering 7 is a flowchart showing camera shake correction processing in the composite panoramic image shooting mode according to the first embodiment. The figure which shows an example of the output signal of A / D converter 102, and its differential signal The block diagram which shows the electric constitution of the digital camera 1 of 2nd Embodiment. The block diagram which shows the internal structure of the blurring correction apparatus of the swing direction of 2nd Embodiment. 8 is a flowchart showing camera shake correction processing in the composite panoramic image shooting mode according to the second embodiment. Illustration for explaining parallel blur The figure which shows the relationship between the blurring amount on the imaging surface of angle blurring and angle blurring and parallel blurring with respect to photographing magnification The block diagram which shows the electrical constitution of the digital camera 1 of 3rd Embodiment. 8 is a flowchart showing camera shake correction processing in the composite panoramic image shooting mode according to the third embodiment. The block diagram which shows the electric constitution of the digital camera 1 of 4th Embodiment. 10 is a flowchart showing a shooting control process in the composite panoramic image shooting mode according to the fourth embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First Embodiment]
<Electric configuration of digital camera>
FIG. 1 is a block diagram showing an electrical configuration of a digital camera 1 according to the first embodiment of the present invention.

  As shown in the figure, the digital camera 1 of the present embodiment includes a photographing lens 10, a CCD 11, a CPU 15, an image sensor driving unit 20, an operation unit 21, an analog signal processing unit 22, an A / D converter 23, a digital signal. The processing unit 26, the correction lens 41, the correction mechanism 42, an equiangular velocity integration target changing circuit 43, a shake detection unit 44, and the like are provided.

  Each unit operates under the control of the CPU 15, and the CPU 15 controls each unit of the digital camera 1 by executing a predetermined control program based on an input from the operation unit 21.

  The CPU 15 has a built-in program ROM, in which various data necessary for control are recorded in addition to the control program executed by the CPU 15. The CPU 15 controls each part of the digital camera 1 by reading the control program recorded in the program ROM into the main memory 24 and sequentially executing the program.

  The main memory 24 is used as a program execution processing area, a temporary storage area for image data, and various work areas.

  The operation unit 21 includes general camera operation means such as a release button, a power switch, a shooting mode dial, and a camera shake correction switch, and outputs a signal corresponding to the operation to the CPU 15.

  The photographing lens 10 includes a zoom lens 10a and a focus lens 10b (see FIG. 2). The lens driving unit 18 changes the angle of view by moving the zoom lens 10a back and forth on the optical axis based on a command from the CPU 15, and moves the focus lens 10b back and forth on the optical axis. Make adjustments.

  The subject light transmitted through the photographing lens 10 is received by the CCD 11 via the correction lens 41, the diaphragm 12, the infrared cut filter 13, and the optical low-pass filter 14.

  The correction lens 41 is driven by the correction mechanism 42. The correction mechanism 42 is configured to be able to move the correction lens 41 in the XY directions within a plane perpendicular to the optical axis by a motor such as a VCM (not shown).

  The shake detection unit 44 is provided to detect a shake (vibration) of the digital camera 1 and outputs a signal corresponding to the angular velocity of the digital camera 1. The equiangular velocity integration target changing circuit 43 controls the correction mechanism 42 so as to move the correction lens 41 in the X and Y directions within a plane perpendicular to the optical axis in accordance with the output signal of the blur detection means 44. Details of the camera shake correction will be described later.

  Reference numeral 12 denotes an aperture, and the aperture drive unit 19 controls the aperture amount of the aperture 12 based on a command from the CPU 15 and adjusts the exposure amount of the CCD 11 to an appropriate exposure amount.

  The infrared cut filter 13 and the optical low-pass filter 14 remove the infrared component and the high frequency component of the subject light incident on the CCD 11, respectively.

  The CCD 11 is provided at the subsequent stage of the optical low-pass filter 14 and receives the subject light incident from the photographing lens 10 and transmitted through the infrared cut filter 13 and the optical low-pass filter 14.

  As is well known, the CCD 11 has a light receiving surface on which a large number of light receiving elements are arranged in a matrix. The subject light is imaged on the light receiving surface of the CCD 11 and converted into an electric signal by each light receiving element.

  The CCD 11 outputs the charges accumulated in each pixel as a serial image signal line by line in synchronization with the vertical transfer clock and horizontal transfer clock supplied from the image sensor driving unit 20. The CPU 15 controls the image sensor driving unit 20 to control the driving of the CCD 11.

  Note that the charge accumulation time (exposure time) of each pixel is determined by an electronic shutter drive signal provided from the image sensor drive unit 20. The CPU 15 instructs the image sensor driving unit 20 on the charge accumulation time.

The output of the image signal is started when the digital camera 1 is set to the shooting mode. In other words, when the digital camera 1 is set to the photographing mode, output of an image signal is started in order to display a through image on the display unit 31. The output of the image signal for the through image is temporarily stopped when the instruction for the main photographing is given, and is started again when the main photographing is finished.

  The image signal output from the CCD 15 is an analog signal, and this analog image signal is taken into the analog signal processing unit 22.

  The analog signal processing unit 22 includes a correlated double sampling circuit (CDS) and an automatic gain control circuit (AGC). The CDS removes noise contained in the image signal, and the AGC amplifies the noise-removed image signal with a predetermined gain. The analog image signal subjected to the required signal processing by the analog signal processing unit 22 is taken into the A / D converter 23.

  The A / D converter 23 converts the captured analog image signal into a digital image signal having a gradation width of a predetermined bit. This image signal is so-called RAW data, and has a gradation value indicating the density of R, G, and B for each pixel.

  The image signal for one frame output from the A / D converter 23 is stored in the main memory 24 via the data bus 34 and the memory control unit 25.

  The control bus 33 and the data bus 34 are connected to the CPU 15 and the memory control unit 25 in addition to the digital signal processing unit 26, compression / decompression processing unit 27, integration unit 28, external memory control unit 30, and display control unit 32. These are configured to be able to transmit and receive information to and from each other via buses 33 and 34.

  The image signal for one frame stored in the main memory 24 is taken into the digital signal processing unit 26 in dot order (pixel order).

  The digital signal processing unit 26 performs predetermined signal processing on the R, G, and B color image signals captured in a dot-sequential manner, and generates an image signal (Y / C) composed of a luminance signal Y and color difference signals Cr and Cb. Signal).

  The compression / decompression processing unit 27 performs compression processing in a predetermined format (for example, JPEG) on the input image signal (Y / C signal) composed of the luminance signal Y and the color difference signals Cr and Cb in accordance with a compression command from the CPU 15. Generate compressed image data. Further, in accordance with a decompression command from the CPU 15, the input compressed image data is subjected to decompression processing in a predetermined format to generate uncompressed image data.

  The accumulating unit 28 takes in R, G, and B image signals stored in the main memory 24 in accordance with a command from the CPU 15 and calculates an accumulated value necessary for AE control. The CPU 15 calculates a luminance value from the integrated value and obtains an exposure value from the luminance value. Further, the aperture value and the shutter speed are determined from the exposure value according to a predetermined program diagram. At this time, if necessary, the light emitting unit 16 is determined to be used as photographing auxiliary light.

  The light emitting unit 16 includes a booster circuit and a capacitor in addition to a xenon tube. The booster circuit boosts the voltage of a battery (not shown) to a high voltage based on a command from the CPU 15, and charges the capacitor with the boosted voltage. After charging, the xenon tube is caused to emit light by discharging the voltage charged in the capacitor to the xenon tube based on a command from the CPU 15.

  The light receiving unit 17 controls the light emission amount of the light emitting unit 16 to be appropriate. The light receiving unit 17 includes a light receiving element, and the light receiving element receives reflected light reflected from the subject as the xenon tube of the light emitting unit 16 emits light. When the amount of received light reaches a predetermined reference amount, the light emission of the light emitting unit 16 is stopped by stopping the discharge of the capacitor of the light emitting unit 16.

  The external memory control unit 30 controls reading / writing of data with respect to the recording medium 29 in accordance with a command from the CPU 15. The recording medium 29 may be detachable from the camera body such as a memory card, or may be built into the camera body. In the case of detachable, a card slot is provided in the camera body, and the card slot is used by being loaded.

  The display control unit 32 controls display on the display unit 31 in accordance with a command from the CPU 15. For example, the display unit 31 displays a through image or an image recorded on the recording medium 29. The display unit 31 is also used as a user interface display screen.

<Principle of camera shake correction>
Next, the principle of camera shake correction of the digital camera 1 will be described.

  The digital camera 1 can be switched between a camera shake ON mode and a camera shake OFF mode by the operation unit 21. In the camera shake ON mode, the correction lens 41 is moved and controlled so that subject image blur (image blur) due to camera shake (camera shake) of the digital camera 1 is cancelled. In the camera shake OFF mode, control is performed so that the correction lens 41 remains stopped.

  FIG. 2 is a diagram showing an optical system of the digital camera 1. The optical system of the digital camera 1 includes a zoom lens 10a, a focus lens 10b, and a correction lens 41. A CCD 11 is disposed on the optical axis a of the optical system, and the CCD 11 converts the received subject light into an electrical signal as described above.

  When camera shake occurs in the digital camera 1, the image of the subject moves on the CCD 11 within one frame, so that an electrical signal of a blurred image is generated from the CCD 11. In order to detect the occurrence of camera shake, a shake detection means 44 is provided in the camera body or lens assembly of the digital camera 1. The shake detection unit 44 includes an X direction gyro sensor (100x in FIG. 3) and a Y direction gyro sensor (not shown), and these gyro sensors output signals representing angular velocities in the X direction and the Y direction, respectively. Here, the horizontal direction (pan direction) of the angle of view is the X direction, and the vertical direction (tilt direction) is the Y direction. Alternatively, a gyro sensor that outputs a signal representing angular acceleration may be used.

  The correction mechanism 42 includes an X-direction correction mechanism 42x (see FIG. 3) and a Y-direction correction mechanism (not shown), and is configured to be able to move the correction lens 41 in the X direction and the Y direction, respectively.

  When camera shake does not occur, the optical axis of the correction lens 41 coincides with the optical axis a of the optical system. When camera shake is detected by the shake detection unit 44, the correction lens 41 is moved in the X direction and / or Y direction by the correction mechanism 42 in accordance with the magnitude and direction of the camera shake. As a result, the image formed on the CCD 11 is almost stopped, and a signal representing a sharp image is output from the CCD 11.

  Here, an example is shown in which the image blur is corrected by moving the correction lens 41 in the X and Y directions. However, the image blur is corrected by moving the CCD 11 in the X and Y directions by the correction mechanism 42. You may comprise so that it may correct | amend.

<Image stabilization control unit>
Next, the equiangular velocity integration target changing circuit 43 will be described. FIG. 3 shows the internal configuration of the shake direction correction apparatus in the swing direction according to the present embodiment, that is, the correction mechanism 42x for correcting camera shake in the X direction, the equiangular velocity integration target change circuit 43, and the shake detection means 44. It is a block diagram.

  As shown in the figure, the equiangular velocity integration target changing circuit 43 includes an equiangular velocity detecting circuit 104, an integrating circuit 105, a phase compensating circuit 106, a multiplier 107, a servo calculation unit 108, a driver 109, and the like. . The blur detection unit 44 includes an X-direction gyro sensor 101x, a high-pass filter 101, A / D converters 102 and 103, and the like.

  When camera shake in the X direction occurs in the digital camera 1, the X direction gyro sensor 100x generates an angular velocity signal corresponding to the camera shake. This angular velocity signal is input to the high pass filter 101. The high-pass filter 101 removes the drift component from the input signal and extracts a high-frequency angular velocity signal. The angular velocity signal from which the drift component has been removed (blur signal after the high-pass filter processing) is converted into a digital signal by the A / D converter 102 and then input to the equiangular velocity integration target changing circuit 43.

  On the other hand, the angular velocity signal of the X direction gyro sensor 100 x is branched before being input to the high pass filter 101 and is also input to the A / D converter 103. The angular velocity signal including the drift component (blur signal before high-pass filter processing) is converted into a digital signal by the A / D converter 103 and then input to the equiangular velocity integration target changing circuit 43 in the same manner. Thus, the signal before and after the high-pass filter processing of the output signal of the X-direction gyro sensor 100x is input to the equiangular velocity integration target changing circuit 43.

  FIG. 4 is a diagram for comparing the characteristics of these two signals. As shown in the figure, the angular velocity detectable band is the entire region from low frequency to high frequency before the high-pass filter processing, whereas the high-pass filter signal is only the high-frequency band.

  The drift component is included in the signal before the high-pass filter process, but is not included in the signal after the high-pass filter process. Although details will be described later, the detection of the equiangular velocity based on these signals is possible when the signal before the high-pass filter processing is used, but not when the signal after the high-pass filter processing is used. is there.

  Returning to the description of FIG. 3, the signals before and after the high-pass filter processing input to the equiangular velocity integration target changing circuit 43 are input to the equiangular velocity detecting circuit 104.

  The equal angular velocity detection circuit 104 includes an angular velocity differential calculation unit, a constant angular velocity state determination calculation unit, and an integration target determination unit (both not shown), and selects one of two input signals having different characteristics. And output to the integration circuit 105.

  The integration circuit 105 calculates the angle signal by integrating the input angular velocity signal.

  This angle signal is input to the phase compensation circuit 106 and phase-adjusted. In the angle signal input to the phase compensation circuit 106, a time until the signal output of the X direction gyro sensor 100x with respect to the shake of the digital camera 1 and a phase delay of the integration processing time in the integration circuit 105 are generated. Therefore, the phase compensation circuit 106 compensates for the phase delay obtained by adding these times.

  The angle signal subjected to the phase compensation processing in the phase compensation circuit 106 is input to the multiplier 107 and multiplied by a correction gain value corresponding to the focal length of the optical system. Even with the same amount of camera shake, the amount of movement of the correction lens 41 is larger when the focal length is long than when the focal length is short. Therefore, the correction gain value increases as the focal length of the photographic lens 10 increases.

  The angle signal output from the multiplier 107 is input to the servo calculation unit 108. At the same time, a signal obtained by converting the current position of the correction lens 41 in the X direction into an angle is input to the servo calculation unit 108 from the X direction correction mechanism 42x.

  The servo calculation unit 108 outputs a signal corresponding to the difference between these signals to the driver 109. The driver 109 supplies the correction lens 41 to a desired amount by supplying a current in a direction corresponding to the sign of the input signal to a motor (not shown) of the correction mechanism 42 with a value corresponding to the magnitude of the input signal. And move in the direction.

<Image stabilization processing>
Next, camera shake correction processing according to the first embodiment will be described.

  The digital camera 1 has a composite panoramic image shooting mode. In this mode, a single panoramic image is generated by combining a plurality of images taken while swinging the camera body in a certain direction. The photographer sets the digital camera 1 to the composite panoramic image shooting mode and presses the shutter button. Thereafter, when the photographer swings (pans) the digital camera 1, the digital camera 1 starts high-speed continuous shooting, and determines that a preset number of images have been taken or that a predetermined angle has been rotated. If so, the shooting is terminated. The camera shake correction processing according to the present embodiment corrects camera shake (image blur) during panning of the digital camera 1.

  FIG. 5 is a flowchart showing camera shake correction processing in the composite panoramic image shooting mode according to the present embodiment.

  When the digital camera 1 is set to the composite panoramic image shooting mode by the operation unit 21, it first determines whether or not the camera shake correction function is turned on (step S1). The presence or absence of the camera shake correction function can be freely switched by the photographer by operating a camera shake correction switch (not shown) of the operation unit 21. If the camera shake correction function is OFF, the camera shake correction process is terminated.

  When the camera shake correction function is ON, the camera shake detection unit 44 starts operating and detects camera shake of the digital camera 1. The output signal of the shake detection means 44 is input to the equiangular velocity integration target changing circuit 43.

  The equiangular velocity detection circuit 104 of the equiangular velocity integration target changing circuit 43 is a blur information before and after the high pass filter processing, that is, a signal (output signal of the A / D converter 102) via the high pass filter 101 of the output of the gyro sensor 100x. Then, a signal that does not pass through the high-pass filter 101 (output signal of the A / D converter 103) is acquired (step S2).

  Next, the angular velocity differential calculation unit of the equal angular velocity detection circuit 104 differentiates the signal after the high-pass filter processing, that is, the output signal of the A / D converter 102 (step S3). With this differential signal, it is possible to detect a change in angular velocity after removal of the drift component.

  The equal angular velocity state determination calculation unit of the equal angular velocity detection circuit 104 determines whether or not the absolute value of the differential value is continuous for a time T or more and equal to or greater than a threshold B (step S4). Note that the time T and the threshold value B may be stored in advance in the integration target change circuit 43, or when the digital camera 1 is set to the composite panorama image shooting mode, the integration target change circuit 43 acquires from the CPU 15. You may comprise.

  FIG. 6A shows an example of an output signal of the A / D converter 102 with the horizontal axis as time, and FIG. 6B shows a signal obtained by differentiating the signal shown in FIG. Similarly, the horizontal axis represents time.

  The output signal of the A / D converter 102 indicates the angular velocity of the digital camera 1. Therefore, a signal obtained by differentiating this signal indicates the angular acceleration of the digital camera 1. In FIG. 6A, the angular velocity of the digital camera 1 gradually increases from time t0 to time t1. Further, it can be seen that the angular velocity does not change from time t1 to time t2, and the digital camera 1 is in a constant angular velocity motion state.

  The angular velocity differential calculation unit of the equal angular velocity detection circuit 104 differentiates the signal shown in FIG. As shown in FIG. 6B, this differential signal has a predetermined value from time t0 to time t1, and is substantially zero from time t1 to time t2.

  As described above, in step S4 in which it is determined whether the absolute value of the differential value is continuous for the time T or more and is the threshold value B or more, the angular velocity of the digital camera 1 gradually increases from time t0 to time t1 in FIG. The presence / absence of rising timing is determined. Generally, a time of about 100 ms is required from when the photographer starts swinging the camera until the camera reaches a predetermined angular velocity and starts a constant angular velocity motion (corresponding to time t0 to t1). Therefore, in step S4, for example, 50 ms can be used as the time T.

  Note that when the camera is swung in a direction opposite to that shown in FIG. 6 (a direction opposite to the normal direction in the X direction), the positive and negative of these signals are inverted. Accordingly, in step S4, the determination is made using the absolute value of the differential signal, so that the determination can be made even when the swing is made in the reverse direction.

  Returning to the flowchart of FIG. If it is determined in step S4 that the absolute value of the differential value is not more than the threshold value B for a time T or longer, the process returns to step S2 and the same processing is performed until the absolute value of the differential value is a time value T or more for a continuous time. repeat.

  If it is determined that the absolute value of the differential value is continuous for the time T or longer and is equal to or greater than the threshold B, it is determined that the swing of the digital camera 1 has started, and the process proceeds to step S5 for detecting a constant angular velocity motion state.

  In step S <b> 5, the angular velocity differential calculation unit of the equal angular velocity detection circuit 104 differentiates the signal before the high-pass filter process, that is, the output signal of the A / D converter 103. Then, the equal angular velocity state determination calculation unit determines whether or not the output signal of the A / D converter 103 is equal to or greater than the threshold value and the differential value is near zero (step S5).

  When the output signal of the A / D converter 103 is equal to or greater than the threshold value and the differential value is near zero, the constant angular velocity state determination calculation unit determines that the digital camera 1 is in a constant angular velocity motion state. Based on the determination result, the integration target determination unit of the equal angular velocity detection circuit 104 outputs the signal before the high-pass filter processing, that is, the output signal of the A / D converter 103, to the integration circuit 105. Accordingly, in this case, the correction amount is calculated based on the signal before the high-pass filter processing, and the correction lens 41 is driven based on the calculated correction amount, thereby correcting camera shake (step S6).

  When the digital camera 1 is swung at an equiangular velocity, the signal after the high-pass filter process is zero, and the shake in the swing direction cannot be detected from the signal after the high-pass filter process. In addition, during the constant angular velocity movement, the drift component can be ignored because the angular velocity fluctuation is large. Therefore, swing detection in the swing direction is performed using the signal before the high-pass filter processing.

  On the contrary, when the output signal of the A / D converter 103 is less than the threshold value or when the differential value is not near zero, the constant angular velocity state determination calculation unit determines that the digital camera 1 is not in the constant angular velocity motion state. Based on the determination result, the integration target determination unit of the equiangular velocity detection circuit 104 outputs the signal after the high-pass filter processing, that is, the output signal of the A / D converter 102, to the integration circuit 105. Therefore, in this case, the correction amount is calculated based on the signal after the high-pass filter processing, and the correction lens 41 is driven based on the calculated correction amount, so that camera shake is corrected (step S7).

  As described above, when the digital camera 1 is not swung at an equiangular velocity, the blur detection in the swing direction is performed using the signal after the high-pass filter processing in order to avoid the influence of the drift component as usual.

  In any case, the camera shake correction process in the Y direction may be performed using the signal after the high-pass filter process of the Y direction gyro sensor output as usual.

  As described above, in this embodiment, it is determined whether or not the digital camera 1 is moving at a uniform angular velocity based on the output of the X-direction gyro sensor 100x. If the digital camera 1 is moving at a uniform angular velocity, the high-pass filter processing of the gyro sensor is performed. The blur correction is performed using the previous signal, and when the motion is not at an equal angular velocity, the blur correction is performed using the signal after the high-pass filter processing of the gyro sensor.

  Thereby, even when the digital camera 1 is swung at an equal angular velocity, it is possible to appropriately perform shake correction in the swing direction. Then, by combining a plurality of images shot by performing blur correction in this way, a panoramic image without blur can be acquired.

[Second Embodiment]
Next, a second embodiment will be described. FIG. 7 is a block diagram illustrating an electrical configuration of the digital camera 1 according to the second embodiment. 1 is different from the block diagram shown in FIG. 1 in that a constant angular velocity driving control change circuit 45 is provided instead of the constant angular velocity integration target changing circuit 43.

  FIG. 8 is a block diagram showing the internal configuration of the correction mechanism 42 for correcting camera shake in the X direction, the shake detection means 44, and the constant angular velocity drive control change circuit 45 according to the present embodiment.

  The correction mechanism 42 is configured to be switchable between position control for controlling the position of the correction lens 41 and speed control for controlling the speed of the correction lens 41.

  The constant angular velocity detection circuit 104 of the constant angular velocity drive control change circuit 45 includes a correction mechanism drive control change unit (not shown) in addition to the angular velocity differential calculation unit and the constant angular velocity state determination calculation unit. The correction mechanism drive control change unit switches between position control and speed control for the control method of the correction mechanism 42x.

  FIG. 9 is a flowchart showing camera shake correction processing in the composite panoramic image shooting mode according to the present embodiment.

  The processing from step S1 to step S5 is the same as that in the first embodiment. That is, the digital camera 1 determines whether or not the digital camera 1 is in an equiangular velocity motion state by determining whether or not the signal before the high-pass filter processing is equal to or greater than a threshold value and the differential value is near zero. Is determined (step S5).

  When the output signal of the A / D converter 103 is equal to or greater than the threshold and the differential value is near zero, the constant angular velocity state determination calculation unit of the constant angular velocity detection circuit 104 indicates that the digital camera 1 is in the constant angular velocity motion state. Judge that there is. Based on the determination result, the correction mechanism drive control change unit of the equiangular velocity detection circuit 104 converts the signal before the high-pass filter processing, that is, the output signal of the A / D converter 103, without passing through the integration circuit 105. 106. In this way, by using the signal before the high-pass filter processing without being integrated, the speed of the correction mechanism 42x is controlled, and camera shake correction is performed (step S11).

  In this case, the angular velocity signal after gain correction output from the multiplier 107 is input to the servo calculation unit 108. At the same time, a signal obtained by converting the current speed of the correction lens 41 into an angular speed is input from the correction mechanism 42 to the servo calculation unit 108. If the speed signal cannot be obtained directly from the correction mechanism 42, the driving speed of the correction mechanism 42 may be calculated based on the state equation of the correction mechanism 42.

  Here, the state equation of the correction mechanism 42 is an expression that describes the behavior of the current, speed, and position of the correction mechanism 42 with respect to an input voltage to a coil (not shown). As physical parameters that determine the behavior of the correction mechanism 42, It is configured using driven mass, elastic load constant, viscous load constant, thrust constant, coil resistance, coil inductance, and the like.

  Using the state equation composed of these, the position information obtained from the X-direction gyro sensor 100x, which is a known value, the input voltage to a coil (not shown) and physical parameters, and the “speed” of the correction mechanism 42 in an unknown state. Can be estimated.

  The servo calculation unit 108 outputs a signal corresponding to the difference between these signals to the driver 109. The driver 109 supplies the correction lens 41 to a desired speed by supplying a current in a direction corresponding to the sign of the input signal to a motor (not shown) of the correction mechanism 42 with a value corresponding to the magnitude of the input signal. Move in the direction (speed control).

  When the output signal of the A / D converter 103 is less than the threshold value or when the differential value is not near zero, the constant angular velocity state determination calculation unit determines that the digital camera 1 is not in the constant angular velocity motion state. Based on this determination result, the correction mechanism drive control change unit outputs the signal after the high-pass filter processing, that is, the output signal of the A / D converter 102 to the integration circuit 105. As a result of the integration of the angular velocity signal by the integration circuit 105, the integration circuit 105 outputs an angle signal. By using this angle signal, the position of the correction mechanism 42x is controlled, and camera shake correction is performed (step S12).

  As described above, according to the second embodiment, when equal angular velocity motion is detected, camera shake correction is performed by speed control without integrating the shake signal. Can be further reduced. Further, since the signal before the high-pass filter processing is used, it is possible to correct even the low frequency blur.

[Third Embodiment]
Next, a third embodiment will be described.

  There are two types of camera shake: angle blur caused by rotation around a point on the optical axis and parallel blur caused by movement in a direction perpendicular to the optical axis.

  If the angle blur angle of the camera is θ and the focal length is f, the blur amount Δy of the image on the image sensor surface is expressed by the following (Equation 1).

Δy = f · tan θ (Formula 1)
That is, it can be seen that the amount of blurring of an image in angular blurring, that is, the blur correction amount is proportional to the focal length f.

FIG. 10 is a diagram for explaining parallel blurring. In the figure, the subject distance is D and the focal length is f. Here, assuming that the subject moves by Y, the blur amount By of the image on the image sensor surface at this time is
By = f · Y / D (Formula 2)
It can be expressed as. From the above (Equation 2), it can be seen that the image blur amount in parallel blur, that is, the blur correction amount is proportional to the focal length f and inversely proportional to the subject distance D. Therefore, even when the focal length is the same, if the shooting magnification is large (= the subject is close), the amount of parallel blurring becomes large. If the subject distance is infinite, the blur amount is zero.

  As described above, it can be seen that, for a subject at a long distance, angle blur becomes a dominant factor of camera shake, but for a subject at a short distance, the influence of parallel blur becomes large.

  FIG. 11 is a diagram illustrating the relationship between the angle blur with respect to the photographing magnification and the blur amount on the imaging surface of the angle blur and the parallel blur. As shown in the figure, under the condition that the photographing magnification is large, the relationship of angle blur <parallel blur is established. Therefore, the correction range of the angle blur is reduced unless parallel blur correction is stopped. Therefore, in this embodiment, the presence / absence of parallel blur correction is controlled.

  FIG. 12 is a block diagram illustrating an electrical configuration of the digital camera 1 according to the third embodiment. 1 is different from the block diagram shown in FIG. 1 in that a parallel shake control changing circuit 46 is provided instead of the equiangular velocity integration target changing circuit 43. The parallel shake control change circuit 46 includes a parallel shake correction control change unit and a correction mechanism drive control unit (not shown).

  In addition to the X-direction gyro sensor 100x and the Y-direction gyro sensor, the shake detection unit 44 includes an X-direction acceleration sensor and a Y-direction acceleration sensor (both not shown), and each performs parallel shake in the X direction and the Y direction. It is configured to be detectable. The parallel blur may be configured to be detected using an angular acceleration sensor.

  The parallel shake control changing circuit 46 controls the correction mechanism 42 so as to move the correction lens 41 in the direction perpendicular to the optical axis in accordance with the output signal of the gyro sensor and the output signal of the acceleration sensor of the shake detection means 44. , Correct angle blur and parallel blur.

  FIG. 13 is a flowchart showing camera shake correction processing in the composite panoramic image shooting mode according to the present embodiment.

  The processing from step S1 to step S5 is the same as before. That is, the digital camera 1 determines whether or not the digital camera 1 is in a constant angular velocity motion state based on the output signal of the gyro sensor 100x (step S5).

  When it is determined that the digital camera 1 is in the constant angular velocity motion state, the parallel shake correction control change unit of the parallel shake control change circuit 46 stops acquiring the parallel shake amount from the X-direction acceleration sensor and calculates the correction amount. To do. Further, the correction mechanism drive control unit drives the correction mechanism 42 by referring only to the amount of angular blur acquired based on the output signal of the X direction gyro sensor 100x (step S21).

  If it is determined that the digital camera 1 is not moving at a constant angular velocity, both angular blur and parallel blur are corrected based on the output signals of the gyro sensor and the acceleration sensor (step S22).

  In any case, both angle blur and parallel blur may be corrected in the Y direction.

  The composite panoramic image shooting mode in which the digital camera 1 is shot while swinging in a certain direction is generally for shooting a landscape or the like, and is considered to be far from the subject. As shown in FIG. 11, parallel blur can be ignored with respect to angular blur when the subject distance is long, and thus the blur correction range in the X direction for angular blur is ensured by stopping correction control for parallel blur. It becomes possible.

[Fourth Embodiment]
Next, a fourth embodiment will be described. In this embodiment, in the combined panoramic image shooting mode, after the shutter button is pressed, the digital camera 1 starts synthesizing the panoramic image after the digital camera 1 enters the equiangular velocity motion state.

  FIG. 14 is a block diagram illustrating an electrical configuration of the digital camera 1 according to the fourth embodiment. 1 differs from the block diagram shown in FIG. 1 in that a blur correction start determination circuit 47 is provided instead of the equiangular velocity integration target change circuit 43. The shake correction start determination circuit 47 is configured to be communicable with the CPU 15 and includes an angular velocity differential calculation unit, a constant angular velocity state determination unit, a shake correction operation start determination unit, and an image synthesis permission signal output unit (not shown). .

  FIG. 15 is a flowchart showing a shooting control process in the composite panoramic image shooting mode according to the present embodiment.

  When the digital camera 1 is set to the composite panoramic image shooting mode by the operation unit 21, it first determines whether or not the camera shake correction function is turned on (step S1).

  When the camera shake correction function is on, the motion detection means 44 starts operating. The blur correction start determination circuit 47 acquires the signal before and after the high-pass filter processing of the output signal of the X direction gyro sensor 100x from the blur detection unit 44 (step S2).

  Next, the angular velocity differential calculation unit of the blur correction start determination circuit 47 differentiates the signal after the high-pass filter processing (step S3), and the constant angular velocity state determination calculation unit determines that the absolute value of the differential value is continuous for time T or more. It is determined whether or not it is equal to or greater than the threshold value B (step S4).

  If it is determined that the absolute value of the differential value is not more than the threshold value B for a time T or longer, the process returns to step S2, and the same processing is repeated until the absolute value of the differential value is not less than the threshold value B for a time T or more. That is, the same processing is repeated until the digital camera 1 is swung.

  If it is determined that the absolute value of the differential value is continuous for the time T or longer and is equal to or greater than the threshold value B, it is determined that the swing of the digital camera 1 has started, and the process proceeds to step S5.

  In step S <b> 5, the angular velocity differential calculation unit of the shake correction start determination circuit 47 differentiates the signal before the high-pass filter processing of the shake detection unit 44. Then, the equal angular velocity state determination unit determines whether or not the signal before the high-pass filter processing is equal to or greater than the threshold value and the differential value is near zero (step S5).

  If the signal before the high-pass filter processing is less than the threshold value, or if the differential value is not near zero, it is determined that the digital camera 1 is not in a constant angular velocity motion state, and the process returns to step S5. Therefore, the process of step S5 is repeated until the digital camera 1 is in a constant angular velocity motion state.

  If the signal before the high-pass filter processing is equal to or greater than the threshold value and the differential value is near zero, it is determined that the digital camera 1 is in a constant angular velocity motion state. Based on the determination result, the blur correction operation start determination unit starts control of the correction mechanism 42 (step S31). As a result, the control of the correction lens 41 is started, and camera shake can be corrected.

  Further, the image composition permission signal output unit of the blur correction start determination circuit 47 outputs an image composition permission signal to the CPU 15. The CPU 15 having acquired this signal starts driving the imaging system such as the CCD 11 and starts synthesizing a panoramic image (step S32).

  As described above, in this embodiment, since the shake operation of the digital camera 1 by the photographer is stabilized and the blur correction and the image synthesis are started, the synthesis with less deterioration while ensuring the correction range in the swing direction. Images can be acquired.

  In this specification, an example of correcting camera shake when shooting while swinging (panning) at a constant speed in the X direction has been described. However, the present invention captures images while swinging (tilting) at a constant speed in the Y direction. It is also applicable to In this case, the same processing may be performed using signals before and after the high-pass filter processing of the gyro sensor in the Y direction. The same applies when panning with the digital camera 1 held vertically (X and Y directions changed by 90 degrees).

  DESCRIPTION OF SYMBOLS 1 ... Digital camera, 10 ... Shooting lens, 11 ... CCD, 15 ... CPU, 21 ... Operation part, 41 ... Correction lens, 42 ... Correction mechanism, 43 ... Conformal speed time integration object change circuit, 44 ... Blur detection means, 45 ... Driving control change circuit at equal angular speed, 46... Parallel shake control change circuit, 47... Shake correction start determination circuit, 100x... X direction gyro sensor, 101. Angular velocity detection circuit, 105 ... integration circuit, 106 ... phase compensation circuit, 107 ... multiplier, 108 ... servo calculation unit, 109 ... driver, 110 ... correction mechanism

Claims (11)

A blur correction device that corrects a subject image blur of an imaging device that converts a received subject image into an image signal by an imaging unit,
A sensor that outputs a blur signal corresponding to the blur of the imaging device;
A high-pass filter that performs high-pass filter processing on the blur signal output from the sensor, and removes and outputs a drift component superimposed on the blur signal;
Based on the blur signal after the high-pass filter processing, blur correction means for optically correcting subject image blur due to the blur,
Based on the blur signal before the high-pass filter processing, a constant angular velocity motion detecting means for detecting whether or not the imaging device is in a constant angular velocity motion state;
With
The blur correction device corrects subject image blurring in a uniform angular velocity motion direction based on a blur signal before the high-pass filter processing when the imaging device is in a uniform angular velocity motion state. . The sensors output blur signals in the pan direction and tilt direction of the imaging device, respectively.
The blur correction unit optically corrects subject image blur due to the blur in each of the pan direction and the tilt direction,
2. The blur correction apparatus according to claim 1, wherein the constant angular velocity motion detecting unit detects whether the constant angular velocity motion direction is a pan direction or a tilt direction based on a blur signal before the high-pass filter processing.   The blur correction unit is based on a correction mechanism that is driven in a plane perpendicular to the optical axis so as to correct blur of the optical axis generated in the imaging unit, and an integrated value of the blur signal after the high-pass filter processing. Position control means for controlling the position of the correction mechanism, and speed control means for controlling the speed of the correction mechanism based on a blur signal before the high-pass filter processing, and the imaging device is in an equiangular velocity motion state 3. The blur correction apparatus according to claim 1, wherein the subject image blur in the direction of constant angular velocity motion is corrected by the speed control unit. The sensor outputs a shake signal corresponding to angle shake and parallel shake,
The blur correction unit optically corrects subject image blur due to the angular blur and parallel blur, and when the image pickup apparatus is in a constant angular velocity motion state, the subject image blur due to parallel blur is detected in the constant angular velocity motion direction. 4. The blur correction device according to claim 1, wherein the correction is stopped.   The constant angular velocity motion detecting means detects whether the imaging device is in a constant angular velocity motion state when a blur signal before the high-pass filter processing is equal to or greater than a predetermined value and a differential value thereof is substantially zero. The blur correction apparatus according to claim 1, wherein:   When the absolute value of the differential value of the blur signal after the high-pass filter processing is equal to or greater than a threshold value for a predetermined time or longer, the equal angular velocity motion detection means is based on the blur signal before the high-pass filter processing based on the blur signal before the high-pass filter processing. 6. The blur correction device according to claim 1, wherein it detects whether or not is in an equiangular velocity motion state. In an imaging device that performs continuous shooting by swinging the device body in a certain direction,
Imaging means for converting a received subject image into an image signal;
A sensor that outputs a blur signal corresponding to the blur of the imaging device;
A high-pass filter that performs high-pass filter processing on the blur signal output from the sensor, and removes and outputs a superimposed drift component;
Based on the blur signal after the high-pass filter processing, blur correction means for optically correcting subject image blur due to the blur,
Based on the blur signal before the high-pass filter processing, a constant angular velocity motion detecting means for detecting whether or not the imaging device is in a constant angular velocity motion state;
With
The blur correction unit corrects subject image blur in the direction of constant angular velocity motion based on a blur signal before the high-pass filter processing when a constant angular velocity motion state of the imaging device is detected. . The imaging device has a composite panoramic image shooting mode,
The image pickup apparatus according to claim 7, further comprising an image composition unit configured to compose the continuously photographed images to generate a panorama image when the composite panorama image photographing mode is set.   9. The imaging apparatus according to claim 8, wherein the image synthesizing unit starts image synthesis when it is detected that the imaging apparatus is in a constant angular velocity motion state.   10. The blur correction unit starts correction of subject image blur in the direction of constant angular velocity motion when it is detected that the imaging device is in a constant angular velocity motion state. Imaging device. A blur correction method for correcting a subject image blur of an imaging device that converts a received subject image into an image signal by an imaging means,
A blur signal acquisition step of acquiring from the sensor a blur signal corresponding to the blur of the imaging device;
A high-pass filter processing step of removing and outputting a drift component superimposed on the acquired blur signal;
A blur correction step of optically correcting subject image blur due to the blur by driving a correction mechanism driven in a plane perpendicular to the optical axis of the imaging unit based on the blur signal after the high-pass filter processing step. When,
Based on a shake signal before the high-pass filter processing step, a constant angular velocity motion detection step for detecting whether or not the imaging device is in a constant angular velocity motion state;
With
In the blur correction step, when the imaging apparatus is in a constant angular velocity motion state, subject image blur in the constant angular velocity motion direction is corrected by driving the correction mechanism based on a blur signal before the high-pass filter processing step. A blur correction method characterized by the above.

Images