JP5146107B2 - Image stabilizer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of the inability to correctly determine a start/end of a user's panning or tilting operation and to appropriately correct the movement, at the start/end of the panning or tilting operation, in a hand-shake correcting device. <P>SOLUTION: The hand-shake correcting device includes a panning or swing-back determining means 208 for determining the start of panning with the same sign continuously appearing for a predetermined time in the output from a first A/D-converting means 204 and determining the end of panning at a timing that a difference between the output from the first A/D-converting means 204 and an output from a second A/D-converting means 205 becomes smaller than a predetermined value and a correction signal deciding means 209 for generating a correction signal, based on the outputs from a difference calculating means 207 and the panning or swing-back determining means 208. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a camera shake correction apparatus used in an imaging apparatus such as a video camera.

  In general, an image pickup apparatus such as a video camera or a still camera uses a camera shake correction technique that reduces blur due to “hand shake” and image shake during shooting. As a camera shake correction technique, for example, there is an optical camera shake correction technique in which a correction lens having a vibration gyro mechanism is incorporated in a range and the optical axis is corrected by moving the correction lens in a direction to cancel the shake.

  However, in such camera shake correction technology, due to the configuration of the camera shake detection circuit, when the operation is stopped after moving the camera such as pan / tilt operation largely, the correction lens is set in a direction to cancel the movement caused by the pan / tilt operation. In order to move, an unnatural swinging phenomenon that the photographed image moves in the reverse direction occurs.

As a technique for reducing such a swing-back phenomenon, Patent Document 1 discloses a vibration detection unit that detects vibration, a pan / tilt detection unit that detects pan and tilt from a signal output from the vibration detection unit, And a shake correction device that performs reset control and correction of an integral value in accordance with the detection result of the tilt.
JP 2007-324929 A

  However, in the camera shake correction apparatus of Patent Document 1, although the start / end of the pan / tilt operation can be determined, in order to issue a reset command to the integral correction unit at the start of the pan / tilt operation and to cancel the reset command at the end, There is a problem that unnatural motion correction is performed immediately after the start / end of the pan / tilt operation.

  In order to solve the above-described problem, an image motion correction apparatus according to the present invention includes a motion detection unit that detects motion, and a first amplification that amplifies the output signal of the motion detection unit based on a first filter characteristic that filters a camera shake frequency. Based on the second filter characteristic for filtering the panning frequency of the output signal of the motion detection unit, the first A / D conversion unit for A / D converting the output signal of the first amplification unit A second amplifying unit for amplifying, a second A / D converting unit for A / D converting the output signal of the second amplifying unit, and an average of signals output from the first A / D converting unit An averaging unit, a difference calculating unit that calculates a difference between an output of the first A / D conversion unit and an output of the averaging unit, an output of the first A / D conversion unit, and the second Based on the output of the A / D converter of the When the panning start determination is performed by the panning / shakeback determination unit and the panning / shakeback determination unit, the averaging unit is stopped, and when the panning end determination is performed, the averaging unit is restarted. Based on the output of the difference calculation unit A correction signal determination unit that generates a correction signal, and a correction signal generation unit that generates a motion correction signal based on the correction signal.

  According to the present invention, it is possible to provide an image motion correction apparatus that accurately determines the start / end of a pan / tilt operation and performs appropriate motion correction at the start / end of the pan / tilt operation.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a video camera 101 according to the first embodiment of the present invention. The video camera 101 captures the subject image formed by the optical system 110 with the image sensor 121. The image data generated by the image sensor 121 is subjected to various processes by the image processing unit 140 and stored in the memory card 164. Further, the image data stored in the memory card 164 or the like can be displayed on the liquid crystal monitor 162. Hereinafter, the configuration of the video camera 101 will be described in detail.

  The optical system 110 includes an objective lens 111, a zoom lens 112, a diaphragm 113, an OIS unit 114, and a focus lens 115. The optical system 110 collects light from the subject and forms a subject image.

  The objective lens 111 is a lens arranged closest to the subject. The zoom lens 112 can enlarge or reduce the subject image by moving along the optical axis of the optical system 110. The diaphragm 113 adjusts the amount of light transmitted through the optical system 110 by adjusting the size of the opening according to the setting of the user or automatically. The OIS unit 114 includes a correction lens that can move in a plane perpendicular to the optical axis. The OIS unit 114 reduces the blur of the subject image by driving the correction lens in a direction that cancels the blur of the video camera 101. The focus lens 115 adjusts the focus of the subject image by moving along the optical axis of the optical system 110.

  The drive system 150 drives each optical element in the optical system 110.

  The image sensor 121 captures a subject image formed by the optical system 110 and generates image data. The image sensor 121 is a CCD image sensor or a CMOS image sensor. The timing generator 122 generates a timing signal for driving the image sensor 121. The image sensor 121 performs various operations such as exposure, transfer, and electronic shutter according to the timing signal generated by the timing generator 122. The AD converter 131 converts the image data generated by the image sensor 121 into a digital signal.

  The image processing unit 140 performs various processes on the image data converted by the AD converter 131. The image processing unit 140 performs processing on the image data generated by the image sensor 121, generates image data to be recorded on the memory card 164, and generates image data to be displayed on the liquid crystal monitor 162. . Further, the image processing unit 140 performs processing on the image data stored in the memory card 164 to generate image data to be displayed on the liquid crystal monitor 162 or to store again in the memory card 164. Or image data to be transmitted to an external device via the communication unit 180. The image processing unit 140 can be realized by a DSP or a microcomputer.

  The preprocessing unit 141 performs various image processing such as gamma correction, white balance correction, and flaw correction on the image data converted by the AD converter 131.

  The compression unit 142 compresses image data by performing DCT (Discrete Cosine Transform), Huffman coding, and the like. The compression unit 142 is, for example, MPEG-2 or H.264. The image data is compressed by a compression format conforming to the H.264 standard. However, the present invention relates to MPEG-2 or H.264. The image data is not limited to H.264 format.

  The decompression unit 143 decodes the compressed image data stored in the memory card 164 into an uncompressed state when the liquid crystal monitor 162 reproduces the compressed image data.

  The controller 160 is a control unit that controls the entire video camera 101. The controller 160 can be realized by a semiconductor element or the like. The controller 160 may be configured only by hardware, or may be realized by combining hardware and software. The controller 160 can be realized by a microcomputer.

  The buffer memory 161 functions as a work memory for the image processing unit 140 and the controller 160. The buffer memory 161 can be realized by, for example, a DRAM or a ferroelectric memory.

  A memory card 164 can be attached to and detached from the card slot 163. The card slot 163 can be mechanically and electrically connected to the memory card 164. The memory card 164 includes a flash memory, a ferroelectric memory, and the like, and can store data.

  The controller 160 can store the generated image file in the memory card 164.

  The liquid crystal monitor 162 can display an image indicated by image data generated by the image sensor 121 or an image indicated by image data read from the memory card 164 or the like. The liquid crystal monitor 162 can display various setting information of the video camera 101, shooting time, and the like.

  The communication unit 180 is means for performing communication with an external device. The communication unit 180 can be configured by a USB communication unit, an HDMI communication unit, or the like.

  The operation member 170 is a component that collectively refers to various operation means. The operation member 170 receives a user instruction and transmits the instruction to the controller 160.

  The motion detection unit 190 detects the motion state of the video camera 101. The controller 160 can acquire information regarding the motion state of the video camera 101 detected by the motion detection unit 190. For example, the motion detection unit 190 can be realized by a rotation sensor or an angular velocity sensor.

  The motion correction device 190 generates a motion correction signal in accordance with the motion of the video camera 101. Details of the configuration of the motion correction apparatus 190 are shown in FIG. A part of the blocks shown in FIG. 2 is realized by the controller 160 shown in FIG.

  The motion correction device 190 includes a motion detection unit 201, a first signal amplification circuit 202, a second signal amplification circuit 203, a first A / D conversion unit 204, and a second A / D conversion unit 205. An averaging unit 206, a difference calculation unit 207, a panning / rebound determination unit 208, a correction signal determination unit 209, and a correction signal generation unit 210.

  The motion detection unit 201 includes a gyro sensor or the like, and detects a physical motion of the apparatus.

  The first signal amplification circuit 202 filters and amplifies the camera shake frequency from the motion detected by the motion detection unit 201. In general, when a person holds the apparatus by hand, hand shake occurs with respect to the apparatus held at a constant frequency. The hand shake frequency is a frequency due to the generated hand shake.

  The second signal amplification circuit 203 filters and amplifies the panning frequency from the motion detected by the motion detection unit 201. The panning frequency is a frequency at the time of panning operation, and is a frequency of approximately 0.3 Hz to 0.6 Hz.

  A first analog / digital conversion unit (hereinafter referred to as an A / D conversion unit) 204 and a second A / D conversion unit 205 are analog components of the first signal amplification circuit 202 and the second signal amplification circuit 203. Digitize the signal.

  The averaging unit 206 obtains a moving average of the motion signals digitized by the first A / D conversion unit 204. The averaging unit 206 is realized by the controller 150 or a dedicated circuit.

  The difference calculation unit 207 calculates a difference and a sign between the motion signal digitized by the first A / D conversion unit 204 and the signal averaged by the averaging unit 206. The difference calculation unit 207 is realized by the controller 150.

  The panning / shakeback determination unit 208 determines the start of panning when the same code continues for a predetermined time with respect to the calculation result of the difference calculation unit 207, and determines the output value of the A / D conversion unit 204 and the A / D conversion unit 205. When the difference between the output values becomes equal to or less than a predetermined value, the end of panning is determined. The panning / shakeback determination unit 208 is realized by the controller 150.

  When the panning / return determining unit 208 determines the start of panning, the correction signal determining unit 209 stops the averaging unit 206, decreases the output value of the difference calculating unit 207, and the panning / return determining unit 208. When determining the end of panning, the averaging unit 206 is restarted, the output value of the difference calculation unit 207 is returned to the normal processing, and a signal for correcting motion is determined. The correction signal determination unit 209 is realized by the controller 150.

  The correction signal generation unit 210 generates a signal for correcting the actual movement of the imaging apparatus based on the output signal of the correction signal determination unit 209. The correction signal generator 210 is realized by the controller 150. The correction signal output from the correction signal generator 210 is input to the drive system 130 and drives the OIS unit 124 to perform motion correction.

  The operation of the motion correction apparatus 190 configured as described above will be described with reference to the flowchart of FIG.

  The motion detection unit 201 detects a physical shake of the apparatus and outputs the detected shake as a signal. The first signal amplification circuit 202 amplifies the output signal. The first A / D converter 204 converts the signal from the first signal amplifier circuit 202 into a digital signal (step 301).

  The second signal amplification circuit 203 amplifies the signal from the motion detection unit 201. The second A / D converter 205 converts the signal from the second signal amplifier circuit 203 into a digital signal (step 302).

  When the determination result (steps 309 to 313 described later) of the panning / return determining unit 208 is “panning” (Yes in step 303), the controller 150 stops the averaging process (step 305). ).

  When the determination result of the panning / shakeback determination unit 208 is “shakeback” (Yes in step 304), the averaging process is restarted (step 306).

  When the determination result of the panning / shakeback determination unit 208 is “normal (no panning or shakeback)” (No in step 304), normal averaging processing is performed (step 307).

  Steps 303 to 307 are processes of the averaging unit 206.

  The difference calculation unit 207 obtains the sign and difference at that time from the output value of the first A / D conversion unit 204 obtained in step 301 and the output value of the averaging unit 206.

  Steps 309 to 313 are processing of the panning / rebound determination unit 208.

  The panning / shakeback determining unit 208 determines “panning” when the codes calculated in step 308 are the same for a predetermined time (Yes in step 309) (step 310). The value of the predetermined time is held in a non-volatile memory (not shown) of the video camera 101.

  The panning / shakeback determination unit 208 determines that the difference between the output value of step 201 and the output value of step 202 is equal to or smaller than a predetermined value when it is determined as “panning” in step 311 (in the case of Yes in step 311). When it becomes (Yes in Step 312), it is determined as “shake back” (Step 313). The predetermined value is held in a nonvolatile memory (not shown) of the video camera 101.

  FIG. 4 shows output signals from the first A / D conversion unit 204 and the second A / D conversion unit 205 when the panning / shakeback determination unit 208 determines “panning” and “shakeback”.

  At the time of 401 in FIG. 4, the output of the difference calculation unit 207 is determined to be “panning” because the same code continues for a predetermined time.

  At the time of 402 in FIG. 4, the difference between the output of the first A / D conversion unit 204 and the output of the second A / D conversion unit 205 is equal to or less than a predetermined value, thereby “shake back”. Is determined.

  In this way, by using the output signals of the first A / D conversion unit 204 and the second A / D conversion unit 204 to determine “panning” and “shake back”, “panning” can be accurately performed. Start and end can be determined.

  The correction signal determination unit 209 generates a signal for correcting the actual movement of the imaging device from the output value of step 308 calculated through steps 301 to 313 (step 314). That is, when the start of panning is determined, the averaging unit 206 is stopped (step 305), the output value of the difference calculating unit 207 is decreased, and when the end of panning is determined, the averaging unit 206 is restarted. (Step S306), the output value of the difference calculation unit 207 is returned to the normal process, and a signal for correcting the motion is determined.

  The correction signal generation unit 210 generates a signal for correcting the actual movement of the imaging device based on the output signal of step 214. The correction signal output from the correction signal generator 210 is input to the drive system 130, drives the OIS unit 124, and performs motion correction (step 315).

  In this way, the correction signal determination unit 209 controls the stop / restart of the averaging unit 206 and determines the motion correction signal based on the output value of the difference calculation unit 207. Therefore, at the start of panning, the correction effect is weakened. At the end of panning, normal correction can be performed, and appropriate motion correction can be performed at the start / end of panning.

  Although the “pan” operation has been described in the present embodiment, the same applies to the “tilt” operation.

  The present invention is an image motion correction device that can quickly determine the start / end of a pan / tilt operation and can perform appropriate motion correction at the start / end of the pan / tilt operation. It can be applied to imaging apparatuses such as video cameras and still cameras that need to be performed, and is useful.

The figure which shows the structure of the video camera to which the motion correction apparatus in one embodiment of this invention is applied. The block diagram which shows the structure of the image motion correction apparatus in one embodiment of this invention The flowchart which shows the process of the image motion correction apparatus in one embodiment of this invention. Diagram for explaining panning / shakeback determination

Explanation of symbols

190 motion compensation device 201 motion detection unit 202 first signal amplification circuit 203 second signal amplification circuit 204 first A / D conversion unit 205 second A / D conversion unit 206 averaging unit 207 difference calculation unit 208 panning -Swing-back determination unit 209 Correction signal determination unit 210 Correction signal generation unit

Claims (2)

A motion detector that outputs a signal indicating the detected motion of the device;
A first signal amplification circuit that filters a signal in a first frequency band from the signal output by the motion detection unit and outputs the first signal after the filter;
A second frequency band signal having a lowest frequency higher than the lowest frequency of the first frequency band is filtered from the signal output by the motion detection unit, and a second signal after filtering is output. Two signal amplifier circuits;
A panning detection unit for detecting that the own device has started a panning operation;
After calculating the difference between the first signal and the second signal and detecting that the panning operation is started by the panning detection unit, the time point when the calculated difference first becomes less than a predetermined value. comprising Minato to-size tough as the beginning of the return swing, a,
Camera shake correction device. An averaging unit for averaging the signals output by the first signal amplifier circuit in a time-series manner;
A correction signal determining unit that generates a correction signal based on the signal averaged by the averaging unit and the signal output by the signal amplification circuit;
The averaging unit resumes series in new averaging time from the time it was considered to be the beginning of the return swing by the previous SL-size tough,
The camera shake correction device according to claim 1.

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