JP5264426B2 - Imaging apparatus, control method therefor, and program - Google Patents

Description

  The present invention relates to an imaging apparatus that performs autofocus during moving image recording, a control method thereof, and a program.

  In recent years, a digital camera as an imaging apparatus has been further reduced in thickness in order to improve carrying convenience. In accordance with this, the photographing lens unit that causes the thickness of the digital camera is also required to be thinner.

  In order to reduce the thickness of the photographing lens unit and maintain the driving torque, it is conceivable to use a gear unit for the driving mechanism of the focus lens. As a result, the driving torque is maintained and the photographing lens unit is thinned. However, since the focus lens is operated via the gear unit, the driving sound is increased. There is a need for autofocus control that uses this photographic lens unit so that the focus lens drive sound is not recorded during moving image recording and can be brought into focus.

  Conventionally, a technique has been proposed in which a moving image has a deeper depth of field than a still image and increases a focused area without moving a focus lens (for example, see Patent Document 1).

In addition, focus lens stop candidate positions are determined in advance, and the focus lens moving time and moving frequency during moving image recording are suppressed by determining the scene change and moving the focus lens at the determined position. A technique has been proposed (see, for example, Patent Document 2).
JP 2006-220729 A JP 2006-237994 A

  However, the technique described in Patent Document 1 has a problem that a blurred image is recorded when a predetermined amount or more is defocused. The technique described in Patent Document 2 also has a problem that the driving sound of the focus lens is recorded.

  An object of the present invention is to provide an imaging apparatus capable of performing focusing during moving image recording without recording sound during driving of a focus lens, a control method therefor, and a program.

In order to achieve the above object, an imaging apparatus according to the present invention includes a photographing lens including a focus lens, an imaging unit, a recording unit that records sound, and image data obtained from the imaging unit. A determination unit that determines whether or not to drive the lens; and when the image data obtained from the imaging unit is recorded as a moving image and the determination unit determines to drive the focus lens, Recording means for changing the recording level of the recording means, operation history of the focus lens before recording the image data obtained from the imaging means as a moving image, and image data obtained from the imaging means are recorded as a moving image Calculating means for obtaining a plurality of focus lens movement candidate positions according to the focal depth of the photographing lens at the time, and the determination means If it is determined that driving the Okasurenzu, and having a drive control means for moving the focus lens to one of the plurality of focus lens movement candidates position obtained by said calculating means.
In order to achieve the above object, a method for controlling an imaging apparatus according to the present invention includes a photographing lens including a focus lens, an imaging means, and a recording means for recording sound. In the determination step of determining whether or not to drive the focus lens using the obtained image data, and when the image data obtained from the imaging means is recorded as a moving image, the focus in the determination step A change step of changing the recording level of the recording means when it is determined to drive the lens; an operation history of the focus lens before recording the image data obtained from the imaging means as a moving image; and the imaging means A plurality of focus lenses according to the depth of focus of the photographing lens when recording the image data obtained from A calculation step for obtaining a movement candidate position; and when the determination step determines that the focus lens is to be driven, the focus lens is moved to one of the plurality of focus lens movement candidate positions obtained in the calculation step And a drive control step .
In order to achieve the above object, a program according to the present invention is a program that causes a computer to execute a control method of an imaging apparatus that includes a photographing lens including a focus lens, an imaging unit, and a recording unit that records sound. An apparatus control method includes: a determination step for determining whether to drive the focus lens using image data obtained from the imaging unit; and recording the image data obtained from the imaging unit as a moving image. When the determination step determines that the focus lens is to be driven, a change step of changing the recording level of the recording unit, and the image data obtained from the imaging unit before recording as a moving image Before recording the operation history of the focus lens and the image data obtained from the imaging means as a moving image The calculation step for obtaining a plurality of focus lens movement candidate positions according to the depth of focus of the photographic lens, and the plurality of focus obtained in the calculation step when the determination step determines that the focus lens is to be driven. And a drive control step of moving the focus lens to any one of the lens movement candidate positions .

  According to the imaging apparatus of the present invention, it is possible to perform focusing during moving image recording without recording the sound during driving of the focus lens.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an external view of a digital camera as an imaging apparatus according to an embodiment of the present invention.

  In FIG. 1, a digital camera 100 includes an image display unit 28 that displays images and various information, a mode switching button 60 that switches various modes, a shutter button 61, and an operation unit 70 that receives various operations from the user.

  The digital camera 100 also includes a power switch 72 for switching power on and power off, a connection cable 111 for connecting the digital camera 100 and an external device, and a connector 112 between the connection cable 111 and the digital camera 100.

  The operation unit 70 includes operation members such as various buttons and a touch panel. Specifically, there are an erase button, a menu button, a SET button, four-direction keys (up button, down button, right button, left button) arranged in a cross, a wheel 73, and the like.

  The digital camera 100 also includes a recording medium slot 201 for storing and communicating a recording medium 200 such as a memory card or a hard disk.

  FIG. 2 is a block diagram illustrating a configuration example of the digital camera of FIG.

  The digital camera 100 includes a photographing lens (including a focus lens) 103, a shutter 101 having a diaphragm function, and an imaging unit 22 including a CCD, a CMOS element, or the like that converts an optical image into an electric signal.

  The following components of the digital camera 100 will be described together with their operations.

  The A / D converter 23 that converts an analog signal into a digital signal is used when the analog signal output from the imaging unit 22 is converted into a digital signal. The A / D converter 23 is also used when converting an analog signal output from the sound control unit 11 into a digital signal.

  The barrier 102 covers the photographing lens 103 and the imaging unit 22 of the digital camera 100 to prevent the imaging unit 22 from being dirty or damaged.

  The timing generation unit 12 supplies a clock signal and a control signal to the imaging unit 22, the audio control unit 11, the A / D converter 23, and the D / A converter 13, and includes a memory control unit 15 and a system control unit 50. Controlled by

  The image processing unit 24 performs resizing processing such as predetermined pixel interpolation and reduction and color conversion processing on the data from the A / D converter 23 or the data from the memory control unit 15. The image processing unit 24 also performs predetermined calculation processing using the imaged (captured) image data, and the system control unit 50 performs exposure control and distance measurement control based on the obtained calculation result.

  Thereby, AF (autofocus) processing, AE (automatic exposure) processing, and EF (flash pre-flash) processing of the TTL (through-the-photographing lens) method are performed. The AF process is performed using the AF evaluation value. For the AF evaluation value, the image processing unit 24 extracts a high frequency component of the image data input from the A / D converter 23, obtains an absolute value of the high frequency component of the image data, and stores the absolute value data within a predetermined region. This is the data accumulated at.

  The image processing unit 24 further performs predetermined calculation processing using the captured image data, and also performs TTL AWB (auto white balance) processing based on the obtained calculation result.

  Output data from the A / D converter 23 is written into the memory 32 via the image processing unit 24 and the memory control unit 15 or directly via the memory control unit 15. The memory 32 is a memory for storing a file header in the case where audio data recorded by the microphone 10, a captured still image or moving image, and an image file are configured. The memory 32 has a storage capacity sufficient to store a predetermined number of still images, a moving image and sound for a predetermined time.

  The compression / decompression unit 16 compresses / decompresses image data by adaptive discrete cosine transform (ADCT) or the like, reads a captured image stored in the memory 32 using the shutter 101 as a trigger, performs compression / processing, The processed data is written into the memory 32.

  The compression / decompression unit 16 reads a compressed image read from the recording unit 19 or the like into the memory 32 and performs expansion processing, and writes the processed data to the memory 32. The image data written in the memory 32 by the compression / decompression unit 16 is filed in the file unit of the system control unit 50 and recorded on the recording medium 200 via the interface (I / F) 18.

  The memory 32 also serves as an image display memory, and the display image data written in the memory 32 is displayed by the image display unit 28 including an LCD or the like via the D / A converter 13.

  The audio signal output from the microphone 10 is converted into a digital signal by the A / D converter 23 via the audio control unit 11 configured by an amplifier or the like, and then stored in the memory 32 by the memory control unit 15.

  On the other hand, the audio data recorded on the recording medium 200 is read into the memory 32, and then input to the audio control unit 11 via the D / A converter 13, and the signal controlled by the audio control unit 11 is transmitted to the speaker. 39 is pronounced.

  The nonvolatile memory 56 is an electrically erasable / recordable memory, and, for example, an EEPROM or the like is used. The nonvolatile memory 56 stores constants, programs, and the like for operation of the system control unit 50.

  The system control unit 50 controls the entire digital camera 100. The system memory 52 expands constants and variables for operation of the system control unit 50, programs read from the nonvolatile memory 56, and the like.

  The first shutter switch SW1 (62), the second shutter switch SW2 (64), and the operation unit 70 of the shutter button 61 are operation means for inputting various operation instructions to the system control unit 50.

  The mode switching button 60 can switch the operation mode of the system control unit 50 to any one of a still image recording mode, a moving image mode, a reproduction mode, and the like.

  The first shutter switch SW1 (62) is turned on while the shutter button 61 provided in the digital camera 100 is being operated (half-pressed), and instructs to start operations such as AF processing, AE processing, AWB processing, and EF processing.

  The second shutter switch SW2 (64) is turned on when the operation of the shutter button 61 is completed (fully pressed), and a series of imaging processing (imaging processing) from reading a signal from the imaging unit 22 to writing image data into the recording medium 200. Instruct the start of operation.

  Each operation member of the operation unit 70 is appropriately assigned a function for each scene by selecting and operating various function icons displayed on the image display unit 28, and functions as various function buttons.

  Examples of the function buttons include an end button, a return button, an image advance button, a jump button, a narrowing button, and an attribute change button. For example, when a menu button is pressed, a menu screen on which various settings can be made is displayed on the image display unit 28. The user can make various settings intuitively using the menu screen displayed on the image display unit 28, the four-way key, and the SET button.

  The power switch 72 switches between power on and power off.

  The power control unit 39 includes a battery detection circuit, a DC-DC converter, a switch circuit that switches a block to be energized, and the like, and detects whether or not a battery is attached, the type of battery, and the remaining battery level. The power supply control unit 39 controls the DC-DC converter based on the detection result and the instruction from the system control circuit 50, and supplies a necessary voltage to each unit including the recording medium 200 for a necessary period.

  The power supply unit 30 includes a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a NiCd battery, a NiMH battery, or a Li battery, an AC adapter, or the like. The connectors 33 and 34 connect the power supply unit 30 and the power supply control unit 39.

  The RTC (Real Time Clock) 40 has a power supply unit therein separately from the power supply control unit 39, and continues the clock operation state even when the power supply unit 30 is turned off. The system control unit 50 performs timer control using the date and time acquired from the RTC 40 at the time of activation.

  The interface 18 connects the digital camera 100 (the system control unit 50 thereof) and the recording medium 200. The connector 35 connects the recording medium 200 and the interface 18. The recording medium attachment / detachment detection unit 98 detects whether or not the recording medium 200 is attached to the connector 35.

  The recording medium 200 includes a recording unit 19 composed of a semiconductor memory, a magnetic disk, and the like, an interface (I / F) 37 with the digital camera 100, and a connector 36 for connecting the recording medium 200 and the digital camera 100. I have.

  The communication unit 110 performs various communication processes such as RS232C, USB, IEEE1394, P1284, SCSI, modem, LAN, and wireless communication.

  A connector (antenna in the case of wireless communication) 112 connects the digital camera 100 to another device via the communication unit 110.

(Shooting process)
FIG. 3 is a flowchart showing a procedure of photographing processing (overall operation) executed by the digital camera of FIG.

  This process is executed under the control of the system control unit 50 in FIG. Each processing step is labeled S.

  When the power switch 72 is operated and the power is turned on, the system control unit 50 initializes flags, control variables, and the like in S301.

  Next, in S302, the system control unit 50 determines the setting position of the mode switching button 60. If the mode switching button 60 is set to the moving image recording mode in S302, the moving image described later with reference to FIG. The process proceeds to the recording mode process (S303).

  If another mode has been set, the process proceeds to S304, and the system control unit 50 executes a process according to the selected mode. If the process is completed, the process proceeds to S305. Examples of other modes include a still image shooting mode for shooting a still image and a playback mode for playing back an image.

  In S305, the system control unit 50 determines the setting position of the power switch 72. If the power switch 72 is set to power on, the system control unit 50 returns to S302. In S305, if the power switch 72 is set to power off, the process proceeds to S306, and the system control unit 50 performs a predetermined end process.

  The termination process includes the following process.

  The display of the image display unit 28 is changed to the end state, the barrier 102 is closed, and the imaging unit 22 is protected. Parameters, setting values, and setting modes including flags and control variables are recorded in the nonvolatile memory 56. Shut off the power to parts that do not require power supply.

  When the end process ends, this flowchart ends.

(Movie recording mode processing)
FIG. 4 is a flowchart showing the procedure of the moving image recording mode process executed in S303 of FIG.

  When the moving image recording mode is started, the system control unit 50 performs through display for displaying the image data from the imaging unit 22 (S400). Subsequently, the system control unit 50 determines whether or not the remaining capacity of the power supply unit 30 including a battery (battery) or the like or the remaining capacity of the recording medium 200 has a problem in the operation of the digital camera 100 (S401). . If there is a problem, the system control unit 50 uses the image display unit 28 to display a predetermined warning by an image or sound (S402), and then returns to S400.

  If there is no problem in the state of the power supply unit 30 and the recording medium 200, the system control unit 50 performs face detection processing for detecting whether or not a human face is present in the through-displayed image signal (S403). . This face detection process (S403) will be described later with reference to FIG.

  In S403, when detecting the human face, the system control unit 50 stores, in the system memory 52, the position coordinates, size (width, height), detected number, reliability coefficient, and the like detected in the image signal as face information. To do. If the human face is not detected, the system control unit 50 sets 0 in areas such as position coordinates, size (width, height), detected number, reliability coefficient, etc. in the system memory 52.

  Subsequently, the system control unit 50 determines whether or not the shutter switch SW1 is pressed (S404), and if not, repeats the face detection process (S403). If the shutter switch SW1 is pressed, the process proceeds to S405.

  In step S405, the system control unit 50 performs distance measurement / photometry processing. At this time, if a face is detected in S403, it is also possible to perform distance measurement within the detected face range. If no face is detected, the distance is measured within a predetermined range. Details of the distance measurement / photometry processing will be described later with reference to FIG.

  FIG. 5 is a diagram illustrating a display screen of the image display unit at the time of face detection.

  Reference numeral 501 is a frame indicating the detected face. It is possible to perform distance measurement within the range of this frame 501.

  FIG. 6 is a diagram illustrating a display screen of the image display unit when no face is detected. FIG. 6 is a diagram showing a display screen of the image display unit before the shutter switch SW1 in FIG. 2 is pressed.

  Reference numeral 601 denotes a frame indicating a range to be measured. Ranging can be performed within this range.

  When the distance measurement / photometry process (S405) is completed, the process proceeds to S406. If the shutter switch SW2 is not pressed (S406) and the shutter switch SW1 is also released (S407), the process returns to S403.

  If the shutter switch SW2 is not pressed and the shutter switch SW1 is kept pressed (S407), the process proceeds to S408, and the system control unit 50 determines whether or not to perform a continuous ranging operation.

  When performing the continuous ranging operation, the system control unit 50 executes a continuous ranging process (S409). The continuous ranging process will be described later with reference to FIG. When continuous distance measurement is not performed, the process returns to the determination of whether the shutter switch SW2 has been pressed (S406).

  As a condition for not performing the continuous distance measurement process (S409), in the present embodiment, it is assumed that focus is not achieved by distance measurement when the shutter switch SW1 is pressed.

  If the shutter switch SW2 is pressed, the process proceeds to S410. In S410, when performing a distance measuring operation during moving image shooting, the system control unit 50 calculates a focus lens movement candidate position used in the distance measuring operation during moving image shooting (S411).

  The focus lens movement candidate position is calculated from the focus lens operation history at the time of the continuous ranging process in S409, the focal depth at the current focal length, and the focus lens position at the start of moving image recording.

  7 is a diagram showing an example of focus lens movement candidate positions when the interval is wide in the digital camera of FIG. 2, and FIG. 8 is an example of focus lens movement candidate positions when the interval is narrow in the digital camera of FIG. FIG.

  The focus lens movement candidate position will be described with reference to FIGS.

  In order to improve the followability of the focus on the subject, if the movement of the main subject is determined to be large from the focus lens operation history during the continuous distance measuring process (S409), the interval is set wide to increase the movement of the main subject. If it is determined that is small, the interval is set narrow. When the depth of focus is deep, the interval is set wide, and when the depth of focus is shallow, the interval is set narrow.

  The focus lens movement candidate position is determined by a combination of the movement of the main subject and the depth of focus. At this interval, a focus lens movement candidate position is placed around the current focus lens position.

  P1, P3, and P4 in FIG. 7 and P5, P7, P8, P9, P10, and P11 in FIG. 8 are focus lens movement candidate positions when there are focus lenses at P2 and P6, respectively.

  The maximum amount of this interval is set to an amount that keeps the operation time within a predetermined time when the focus lens is operated at the maximum speed. The predetermined time is based on the minimum time that can be detected by a person (about the minimum time). When the focus lens is operated for this predetermined time, the recording level is lowered.

  By setting the predetermined time to be the minimum time that can be detected by a person, it is possible to perform recording that feels like recording continues. The focus lens movement candidate position obtained by calculation is stored in the system memory 52.

  As a condition for not performing the distance measuring operation during moving image shooting, in the present embodiment, it is assumed that focus is not achieved by distance measurement when the shutter switch SW1 is pressed.

  Next, the system control unit 50 starts moving image shooting (S412). After the moving image shooting process is started, next, the moving image recording is performed until the shutter switch SW2 is pressed and released (S413). The operation of the shutter switch SW1 is not accepted until the moving image recording is finished.

  During the moving image shooting process (S413), the system control unit 50 determines whether or not to perform a distance measuring operation during moving image shooting (S414), and when the system control unit 50 determines to perform the distance measuring operation, Distance processing (ranging processing during moving image shooting) (S415) is performed. The moving image shooting process (S413) will be described later with reference to FIG. 17, and the distance measuring process during shooting (S415) will be described later with reference to FIG.

  Next, the system control unit 50 determines whether or not the photographing is finished (S416). Shooting is terminated when the shutter switch SW2 is pressed or released, or the recording medium 200 runs out of free space or the memory 32 runs out of space.

  When shooting is completed, the system control unit 50 then performs a moving image recording process (S417). The moving image recording process (S417) will be described later with reference to FIG. When the moving image recording process (S417) ends, the system control unit 50 ends a series of shooting operations and returns to the shooting standby state.

(Continuous ranging process)
FIG. 9 is a flowchart showing the procedure of the continuous ranging process executed in S409 of FIG.

  When the continuous ranging process is started, first, the system control unit 50 determines whether the main subject is a face or other (S501). In the present embodiment, the face to be the main subject and the subject to be the main subject are determined as the subjects when the distance measurement / photometry operation is performed by pressing the shutter switch SW1. The main subject can also be set in advance.

  If the main subject is a face, the system control unit 50 performs face detection (S502). Next, the system control unit 50 determines whether or not a face has been detected (S503). If no face is detected, the continuous ranging operation is interrupted (S504), and the continuous ranging operation is terminated. . If a face is detected, the process proceeds to S505.

  If the main subject is not a face, the system control unit 50 performs subject detection processing (S506). This subject detection process (S506) will be described later with reference to FIG.

  In S <b> 506, when the subject is detected, the system control unit 50 stores the position coordinates, size (width, height), reliability coefficient, and the like detected in the image signal as subject information in the system memory 52. When the subject is not detected, the system control unit 50 sets 0 in areas such as position coordinates, size (width, height), and reliability coefficient in the system memory 52.

  In the present embodiment, when the shutter switch SW1 is pressed and a distance measurement operation is performed in a predetermined area and an in-focus state is detected, an object moving within the area is detected and set as the main subject.

  FIG. 10 is a diagram showing a display screen of the image display unit in a state where the shutter switch SW1 in FIG.

  The display of the image display unit 28 when the subject detection process (S506) is performed will be described with reference to FIGS. 6 and 10 described above.

  As described above, reference numeral 601 in FIG. 6 represents a frame of a range (area) to be measured when the shutter switch SW1 is pressed, and reference numeral 602 in FIG. 10 represents a frame of a range detected by subject detection. Yes. The area of the detected subject is the area of the object that is operating as shown in FIG.

  Next, the system control unit 50 determines whether or not a subject has been detected (S507). If no subject has been detected, the continuous ranging operation is interrupted (S508), and the continuous ranging process is terminated. . If a subject is detected, the process proceeds to S505.

  Next, the system control unit 50 determines whether or not the continuous ranging operation is interrupted (S505). If continuous ranging is interrupted, the system control unit 50 determines whether or not to resume the continuous ranging operation (S509).

  The system control unit 50 checks the amount of change in the information of the main subject detected this time with respect to the information of the main subject detected last time. If the amount of change is less than the predetermined amount, the system control unit 50 resumes the continuous ranging operation. If it exceeds the fixed value, the continuous ranging operation is not resumed. Information for examining the amount of change includes position, size, and the like. If the continuous ranging operation is not resumed, the continuous ranging process is terminated.

  Next, the system control unit 50 determines whether a face is detected (S510). If a face is detected, the system control unit 50 sets an AF evaluation value acquisition area in the detected face area (S511). If no face is detected, the system control unit 50 sets an AF evaluation value acquisition area in the area of the detected subject (S512).

  Next, the system control unit 50 acquires the AF evaluation value in the set area at the current focus lens position (S513), and proceeds to S514.

  The system control unit 50 moves the focus lens by a predetermined amount in the near focus direction (S514), and acquires the AF evaluation value at that position (S515). Next, the system control unit 50 moves the focus lens by a predetermined amount in the far-focus direction (S516), and acquires an AF evaluation value at that position (S517).

  The system control unit 50 compares the AF evaluation values acquired at the respective positions, and selects the focus lens position where the AF evaluation value is the maximum value (S518). When the initial position is selected, the system control unit 50 moves the focus lens to the initial position (S519).

  When the position moved in the near focus direction is selected, the system control unit 50 moves the focus lens to the position moved in the near focus direction (S520). When the position moved in the direction of focusing on the far side is selected, the system control unit 50 moves the focus lens to the position moved in the direction of focusing on the far side (S521).

  Next, the system control unit 50 stores the operation history of the focus lens. For example, in the case where information has been stored in which the position where the focus is continuously moved to the near side is selected, it can be determined from the information that the main subject is moving toward the near side.

  Further, it can be determined from the frequency of movement of the focus lens whether the main subject is moving largely or the main subject is moving little. The system control unit 50 stores the operation history (S522), and the continuous ranging process ends.

(Ranging during shooting)
FIG. 11 is a flowchart showing the procedure of the distance measuring process during photographing executed in S415 of FIG.

  When the distance measuring process during photographing is started, first, the system control unit 50 determines whether the main subject is a face or the other (S601). In the present embodiment, the face to be the main subject and the subject to be the main subject are determined as the subjects when the distance measurement / photometry operation is performed by pressing the shutter switch SW1. The main subject can also be set in advance.

  If the main subject is a face, the system control unit 50 performs face detection processing (S602). Next, the system control unit 50 determines whether or not a face has been detected (S603). If no face is detected, the ranging operation during shooting is interrupted (S604), and the ranging process during shooting is performed. finish. If a face is detected, the process proceeds to S605.

  If the main subject is not a face, the system control unit 50 performs subject detection processing (S606). This subject detection process (S606) will be described later with reference to FIG.

  Next, the system control unit 50 determines whether or not a subject has been detected (S607). If no subject has been detected, the ranging operation during shooting is interrupted (S608), and ranging processing during shooting is performed. finish. If a subject is detected, the process proceeds to S605.

  Next, the system control unit 50 determines whether or not the distance measuring operation during shooting is interrupted (S605). If the ranging operation during photographing is interrupted, the system control unit 50 next determines whether or not to resume the ranging operation during photographing (S609).

  The amount of change of the information of the main subject detected this time is checked against the information of the main subject detected last time. If the amount of change is less than the predetermined amount, the ranging operation during shooting is restarted. Do not resume the distance measuring operation during shooting. Information for examining the amount of change includes position, size, and the like. If the ranging operation during photographing is not resumed, the ranging processing during photographing is terminated.

  Next, the system control unit 50 determines whether a face is detected (S610). When a face is detected, the system control unit 50 first compares the information of the face detected this time with the face position detected last time (S611).

  When the position detected last time and the position detected this time are within the predetermined range, the system control unit 50 next compares the face sizes (S612). If the face size has not changed by a predetermined value or more, the ranging process during photographing is terminated.

  If no face is detected, the system control unit 50 compares the subject position detected this time with the subject position detected last time (S613). When the subject position detected last time and the subject position detected this time are within the predetermined range, the system control unit 50 next compares the subject sizes (S614). If the subject size has not changed by a predetermined value or more, the ranging process during photographing is terminated.

  If the detected size has changed by a predetermined value or more, the system control unit 50 next acquires an AF evaluation value at the detected main subject position (S615). It is determined whether or not the acquired AF evaluation value has changed below a predetermined value (S616).

  The predetermined value is calculated based on the AF evaluation value at the time when moving image recording is started. In addition, since the area from which the AF evaluation value is acquired varies depending on the detected main subject size, normalization based on the AF evaluation value acquisition area size is performed on the AF evaluation value.

  If the AF evaluation value has not changed below the predetermined value, the distance measuring process during photographing is terminated. If the AF evaluation value has changed below the predetermined value, the system control unit 50 next determines the moving direction of the main subject (S617).

  This is determined based on the detected size of the face or subject that is the detected main subject. If the size detected this time is smaller than the size detected last time, it is determined that the main subject is moving to the far side, and if it is larger, it is determined that the main subject is moving to the near side.

  For example, when the face frame 501 in FIG. 5 described above becomes larger as the face frame 502 in FIG. 12 due to the approach of the main subject, it is determined that the subject is approaching.

  Further, when the subject frame 602 in FIG. 10 described above becomes smaller as the subject frame 603 in FIG. 13 due to the main subject moving away, it is determined that the subject is moving away.

  The system control unit 50 can determine whether the main subject is approaching or moving away without moving the focus lens and measuring the distance by determining the detection size of the face and the subject.

  When it is determined that the main subject has moved to the near side, the system control unit 50 reads the focus lens movement candidate position stored in the system memory 52 and moves the focus object to a position advanced by one point. Start (S618). For example, if the current focus lens position is P2 in FIG. 7, the movement to P3 is started.

  When it is determined that the main subject has moved to the far side, the system control unit 50 reads the focus lens movement candidate position stored in the system memory 52 and moves the point to the position advanced by one point to the far side. Start (S619). For example, if the current focus lens position is P2 in FIG. 7, the movement to P1 is started.

  Next, the system control unit 50 performs setting to lower the recording level (S620). The amount to be lowered may be set in advance, or may be determined from the driving speed of the focus lens and the ambient noise level.

  Next, the system control unit 50 determines whether or not the movement of the focus lens has ended (S621). If the movement has not ended, the process returns to the movement end determination (S621). When the movement is finished, the system control unit 50 returns the recording level to the normal level (S622), and the ranging process during photographing is finished.

  In this way, when the shutter button SW1 before moving image recording is pressed, the main subject is determined, and while the shutter button SW1 is kept pressed, continuous ranging operation is performed so as to keep focusing on the main subject. I do.

  When video recording is started, the focus lens is driven by intermittently driving the focus lens according to the detection state of the main subject and the state of the AF evaluation value, and the recording state at the time of driving is changed, thereby driving the focus lens. You can shoot movies that are in focus without recording sound.

(Face detection process)
FIG. 14 is a flowchart showing the procedure of the face detection process executed in S403 of FIG.

  The system control unit 50 applies horizontal and vertical bandpass filters to the image signal (S701) (S702, S703), and detects edge components. Thereafter, the system control unit 50 performs pattern matching (S704) of the detected edge components, and extracts a candidate group of eyes, nose, mouth, and ears.

  The system control unit 50 determines an eye pair that satisfies a preset condition (for example, the distance between two eyes, inclination, etc.) from the eye candidate group extracted in S704, Only a pair having a pair is narrowed down as a candidate group (S705).

  The system control unit 50 associates the narrowed-down eye candidate group with the other parts (nose, mouth, ears) that form the corresponding face, and passes the preset non-face filter (S706). , Detect the face. The system control unit 50 outputs face information according to the detection result (S706), and ends the process.

  In this way, it is possible to detect subject information by extracting feature amounts of image data using image data displayed as a through image. In the present embodiment, face information is taken as an example of subject information, but there are various other information such as red-eye determination in such subject information.

(Subject detection process)
FIG. 15 is a flowchart showing the procedure of subject detection processing executed in S506 of FIG.

  The system control unit 50 cuts out and extracts a specific part of the image signal (S801) according to the necessity (S802). The system control unit 50 applies horizontal and vertical bandpass filters to the extracted region (S803, S804) to detect edge components. The system control unit 50 also extracts color information in the same area (S805).

  Thereafter, the system control unit 50 performs pattern matching (S806) from the detected edge component and color information, and extracts a preset subject.

  As a method for setting the subject, it may be stored in advance in the digital camera 100, or when the shutter switch SW1 is pressed and it is determined that the subject is in focus as a result of the distance measurement, the movement in the distance-measured area is determined. The subject information may be extracted and the subject information may be stored.

  In this way, it is possible to detect subject information by extracting feature amounts of image data using image data displayed as a through image.

(Ranging / photometry processing)
FIG. 16 is a flowchart showing the procedure of distance measurement / photometry processing executed in S405 of FIG.

  The system control unit 50 reads out the charge signal from the imaging unit 22, and sequentially reads the captured image data into the image processing unit 24 via the A / D converter 23 (S901). Then, using the sequentially read image data, the image processing unit 24 performs predetermined calculations used for TTL AE processing, EF processing, and AF processing.

  In each process here, a specific portion of the total number of captured pixels is extracted by cutting out a necessary portion according to necessity and used for calculation. This makes it possible to perform optimum calculations for different modes such as the center-weighted mode, the average mode, and the evaluation mode in each of the TTL method AE, EF, AWB, and AF processes.

  Using the calculation result in the image processing unit 24, the system control unit 50 performs AE control (S903) until it is determined that the exposure (AE) is appropriate (S902).

  If it is determined that the exposure is appropriate (S902), the system control unit 50 stores the measurement data and / or setting parameters in the internal memory or the system memory 52.

  Using the calculation result in the image processing unit 24 and the measurement data obtained by the AE control, the system control unit 50 uses the image processing unit 24 until it is determined that the white balance (AWB) is appropriate (S904). Color processing parameters are adjusted to perform AWB control (S905).

  If it is determined that the white balance is appropriate (S904), the system control unit 50 stores the measurement data and / or setting parameters in the internal memory or the system memory 52.

  The system control unit 50 uses the measurement data obtained by the AE control and the AWB control to perform AF control until ranging (AF) is determined to be in focus (S906).

  If it is determined that the distance measurement is in focus (S906), the system control unit 50 stores the measurement data and / or setting parameters in the internal memory or the system memory 52, and ends the distance measurement / photometry process.

(Movie shooting process)
FIG. 17 is a flowchart showing the procedure of the moving image shooting process executed in S413 of FIG.

  The system control unit 50 sequentially stores the image data captured by the imaging unit 22 in the memory 32 at a predetermined frame rate (S1001). At the same time, the system control unit 50 stores the voice recorded from the microphone 10 in the memory 32 through the voice control unit 11 and the A / D converter 23 (S1001). In this embodiment, digital data in the PCM format is assumed.

  Subsequently, the system control unit 50 performs image processing such as image size conversion for recording the image data stored in the memory 32 in a file by the image processing unit 24 (S1002). Then, the compression / decompression unit 16 performs compression processing (S1003) and stores it in the memory 32 (S1004).

  18 is a diagram showing a configuration example of a moving image file (moving image data) recorded on the recording medium in FIG.

  At the beginning of the data, a fixed-length header area (18-1) consisting of data such as a video frame rate and an audio sampling rate, and a fixed-length audio data area (18) for storing audio data for 1 second immediately thereafter. -2).

  The sound data is obtained by sampling the sound input to the microphone 10 into digital data through the sound control unit 11 and the A / D converter 23, and is stored in the memory 32. Immediately thereafter, frame data (18-3, 18-4, 18-5, 18-6) recorded at a predetermined frame rate is sequentially stored in the memory 32, and data is sequentially generated in units of one second.

  When the data for one second is accumulated, the system control unit 50 records the moving image data accumulated in the memory 32 in parallel with the moving image and audio recording processing on the recording medium 200 (S1004).

  The system control unit 50 repeats these processes until a moving image stop request is detected. The moving image shooting process is continued until the second shutter switch SW2 (64) is redetected, the recording medium 200 has no free space, or the memory 32 has no free space.

(Movie recording process)
FIG. 19 is a flowchart showing the procedure of the moving image recording process executed in S417 of FIG.

  A moving image file recorded in the moving image recording mode is given an extension AVI, and a thumbnail file for recording management information is given an extension THM.

  When the moving image recording process is stopped under the above conditions, the system control unit 50 writes the remaining moving image data in the memory 32, and then stores the index information (18-) in FIG. 18) is recorded (S1101).

  Next, after generating header information such as the total number of frames (S1102), the system control unit 50 describes the total data size in the directory entry and records the information on the recording medium 200 (S1103). This ends the recording of the moving image file.

  Subsequently, the system control unit 50 generates a thumbnail file having the same number as the moving image file name from the moving image file management information, and ends the moving image recording (S1104).

  The object of the present invention can also be achieved by executing the following processing. That is, a storage medium storing software program codes for realizing the functions of the above-described embodiments is supplied to a system or apparatus, and a computer (or CPU, MPU, etc.) of the system or apparatus is stored in the storage medium. This is a process of reading the program code.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code and the storage medium storing the program code constitute the present invention.

  Moreover, the following can be used as a storage medium for supplying the program code. For example, floppy (registered trademark) disk, hard disk, magneto-optical disk, CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD + RW, magnetic tape, nonvolatile memory card, ROM or the like. Alternatively, the program code may be downloaded via a network.

  Further, the present invention includes a case where the function of the above-described embodiment is realized by executing the program code read by the computer. In addition, an OS (operating system) running on the computer performs part or all of the actual processing based on the instruction of the program code, and the functions of the above-described embodiments are realized by the processing. Cases are also included.

  Furthermore, the present invention includes a case where the functions of the above-described embodiment are realized by the following processing. That is, the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Thereafter, based on the instruction of the program code, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing.

1 is an external view of a digital camera as an imaging apparatus according to an embodiment of the present invention. It is a block diagram which shows the structural example of the digital camera of FIG. 3 is a flowchart showing a procedure of photographing processing (overall operation) executed by the digital camera of FIG. 2. It is a flowchart which shows the procedure of the moving image recording mode process performed by S303 of FIG. It is a flowchart which shows the procedure of the moving image recording mode process performed by S303 of FIG. It is a figure which shows the display screen of the image display part at the time of face detection. It is a figure which shows the display screen of the image display part at the time of face non-detection. FIG. 3 is a diagram illustrating an example of focus lens movement candidate positions when the interval is wide in the digital camera of FIG. 2. FIG. 3 is a diagram illustrating an example of focus lens movement candidate positions when the interval is narrow in the digital camera of FIG. 2. It is a flowchart which shows the procedure of the continuous ranging process performed by S409 of FIG. It is a flowchart which shows the procedure of the continuous ranging process performed by S409 of FIG. It is a figure which shows the display screen of the image display part at the time of object detection. FIG. 5 is a flowchart illustrating a procedure of a distance measuring process during photographing executed in S415 of FIG. FIG. 5 is a flowchart illustrating a procedure of a distance measuring process during photographing executed in S415 of FIG. It is a figure which shows the display screen of the image display part at the time of the ranging operation during imaging | photography while detecting a face. It is a figure which shows the display screen of the image display part at the time of the ranging operation which detects a to-be-photographed object and is imaged. 5 is a flowchart illustrating a procedure of face detection processing executed in S403 of FIG. 10 is a flowchart illustrating a procedure of subject detection processing executed in S506 of FIG. 5 is a flowchart illustrating a procedure of distance measurement / photometry processing executed in S405 of FIG. 4. 4 is a flowchart showing the procedure of the moving image shooting process executed in S413 of FIG. It is a figure which shows the structural example of the moving image file (moving image data) recorded on the recording medium in FIG. It is a flowchart which shows the procedure of the moving image recording process performed by S417 of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Digital camera 10 Microphone 11 Audio | voice control part 12 Timing generation part 15 Memory control part 16 Compression / decompression part 22 Imaging part 24 Image processing part 28 Image display part 32 Memory 50 System control part 103 Shooting lens

Claims (5)

A photographic lens including a focus lens;
Imaging means;
Recording means for recording audio;
Determination means for determining whether or not to drive the focus lens using image data obtained from the imaging means;
A change unit that changes a recording level of the recording unit when the determination unit determines to drive the focus lens when the image data obtained from the imaging unit is recorded as a moving image;
According to the operation history of the focus lens before recording the image data obtained from the imaging unit as a moving image, and the focal depth of the photographing lens when recording the image data obtained from the imaging unit as a moving image, A calculation means for obtaining a plurality of focus lens movement candidate positions;
A drive control means for moving the focus lens to one of the plurality of focus lens movement candidate positions obtained by the calculation means when it is determined by the determination means to drive the focus lens;
An imaging device comprising:   The determination means, as a condition for determining to drive the focus lens, that the change in the position of the main subject in the image data is larger than a predetermined range, and that the change in the size of the main subject in the image data is larger than a predetermined value. The imaging apparatus according to claim 1, further comprising at least one of an AF evaluation value of the main subject in the image data being equal to or less than a predetermined value. The plurality of spacing of the focus lens movement candidate position, the imaging apparatus according to claim 1 or claim 2 movement of the focus lens is characterized in that it is a distance that falls within a predetermined time. In a control method of an image pickup apparatus having a photographing lens including a focus lens, an image pickup means, and a sound recording means for recording sound,
A determination step of determining whether or not to drive the focus lens using image data obtained from the imaging means;
A change step of changing the recording level of the recording means when it is determined that the focus lens is driven in the determination step when recording the image data obtained from the imaging means as a moving image;
According to the operation history of the focus lens before recording the image data obtained from the imaging unit as a moving image, and the focal depth of the photographing lens when recording the image data obtained from the imaging unit as a moving image, A calculation step for obtaining a plurality of focus lens movement candidate positions;
A drive control step of moving the focus lens to one of the plurality of focus lens movement candidate positions obtained in the calculation step when it is determined that the focus lens is driven in the determination step;
An image pickup apparatus control method comprising: In a program for causing a computer to execute a control method of an imaging apparatus having a photographing lens including a focus lens, an imaging means, and a recording means for recording sound,
The control method of the imaging device is:
A determination step of determining whether or not to drive the focus lens using image data obtained from the imaging means;
A change step of changing the recording level of the recording means when it is determined that the focus lens is driven in the determination step when recording the image data obtained from the imaging means as a moving image;
According to the operation history of the focus lens before recording the image data obtained from the imaging unit as a moving image, and the focal depth of the photographing lens when recording the image data obtained from the imaging unit as a moving image, A calculation step for obtaining a plurality of focus lens movement candidate positions;
A drive control step of moving the focus lens to one of the plurality of focus lens movement candidate positions obtained in the calculation step when it is determined that the focus lens is driven in the determination step;
A program comprising:

Images