JP4534250B2 - Movie imaging apparatus and program thereof - Google Patents

Description

  The present invention relates to a moving image capturing apparatus and a program thereof, and more particularly to a moving image capturing apparatus that performs a focusing operation during moving image capturing and a program thereof.

In a conventional moving image pickup apparatus, for example, a digital camera, the subject is focused by performing contrast AF processing continuously during moving image shooting and when a through image of the subject is displayed (moving image pickup). It was.
In contrast AF processing, the focus lens is driven, the contrast component is detected from the imaging signal that is the CCD output at that time, the waveform is interpreted, that is, the focus is on the lens position where the high-frequency component is the largest. This is to adjust the focus by adjusting the lens, and this operation is performed at regular intervals.

In addition, there is a technique in which a subject is focused by pan focus when shooting a moving image or displaying a through image of the subject.
For example, at the time of moving image shooting and through image display, the current zoom position information is recognized, and the pan focus position is determined based on the zoom position information (Patent Document).

Japanese Patent Laid-Open Publication No. 2001-208954 (see paragraphs “0034” to “0052”)

However, in contrast AF processing that is continuously performed during moving image shooting and through-image display, the focus position is searched while driving the focus lens, which increases the operation time, resulting in blurring. It takes a long time to capture an image. In addition, when recording a subject's voice or the like, the period of noise mixed in the recorded voice also becomes long.
Further, according to the invention described in the above-mentioned patent document, since the pan focus position is determined based only on the zoom position, it is not possible to perform the focus according to the shooting environment.

  Therefore, the present invention has been made in view of such conventional problems, and an object of the present invention is to provide a moving image pickup apparatus and a program thereof that can quickly perform a focusing operation according to the shooting environment during moving image pickup. And

In order to achieve the above object, an image pickup apparatus according to the first aspect of the present invention provides:
Optical zoom magnification setting means for setting the optical zoom magnification;
Optical zoom means for moving the zoom lens according to the optical zoom magnification set by the optical zoom magnification setting means;
Zoom lens position acquisition means for acquiring a lens position of the zoom lens;
Imaging means for imaging a subject;
Moving image imaging control means for controlling imaging of a moving image of a subject by the imaging means;
A determination unit that periodically determines a shooting scene based on a subject image when imaging control is performed by the moving image imaging control unit;
Focus control means for focusing on the subject by changing the lens position of the focus lens according to the shooting scene determined by the determination means and the lens position of the zoom lens acquired by the zoom lens position acquisition means; ,
It is provided with.

For example, as described in claim 2, the focus control unit includes:
When the same photographing scene is continuously determined a predetermined number of times by the determining means, the subject is focused by changing the lens position of the focus lens according to the determined shooting scene. Good.

In addition, for example, as described in claim 3, the image processing apparatus includes a determination unit that determines the type of priority focus based on the shooting scene determined by the determination unit.
The focus control means includes
The subject may be focused by changing the lens position of the focus lens according to the type of priority focus determined by the determination means.

For example, as described in claim 4 , the focus control means includes
A pan focus control unit that focuses the subject by changing the lens position of the focus lens according to the focus position of the pan focus corresponding to the shooting scene determined by the determination unit may be included.

Further, for example, as described in claim 5 , the pan focus control means includes:
PF position acquisition means for acquiring a focus position of pan focus based on the shooting scene determined by the determination means,
The subject may be focused by changing the lens position of the focus lens in accordance with the pan focus focus position acquired by the PF position acquisition means.

Further, for example, as described in claim 6 , the first storage unit that stores in advance the focus position of the pan focus corresponding to the shooting scene is provided,
The PF position acquisition means includes
The focus position of pan focus may be acquired from the first storage unit based on the shooting scene determined by the determination unit.

Further, for example, as described in claim 7 , the AF evaluation value of the captured image captured by the moving image capturing control unit is detected while the lens position of the focus lens is changed, and the detected plurality of AFs Contrast AF means for moving the focus lens to the focus lens position based on the evaluation value,
The focus control means includes
In accordance with the shooting scene determined by the determining unit, the lens position of the focus lens that detects the AF evaluation value of the captured image captured by the moving image capturing control unit is changed by the contrast AF unit, and the subject is changed. A first AF control unit that performs focusing may be included.

For example, as described in claim 8 , the first AF control means includes
A focus position acquisition unit that acquires a plurality of focus positions based on the shooting scene determined by the determination unit;
The lens position of the focus lens that detects the AF evaluation value by the contrast AF unit may be limited to a plurality of focus positions acquired by the focus position acquisition unit.

For example, as described in claim 9 , the plurality of focus positions acquired by the focus position acquisition unit may have a constant sampling interval.

In addition, for example, as described in claim 10 , a second storage unit that stores a plurality of focus positions corresponding to the shooting scene in advance is provided.
The focus position acquisition means includes
A plurality of focus positions may be acquired from the second storage unit based on the shooting scene determined by the determination unit.

For example, as described in claim 11 , the first AF control unit includes:
A range acquisition unit for acquiring a lens range of a lens position of a focus lens for detecting an AF evaluation value by the contrast AF unit based on a shooting scene determined by the determination unit;
The lens position of the focus lens that detects the AF evaluation value by the contrast AF unit may be limited to the lens range of the lens position of the focus lens acquired by the range acquisition unit.

For example, as described in claim 12 , the first AF control unit includes:
An interval acquisition unit that acquires a sampling interval of a lens position of a focus lens that detects an AF evaluation value by the contrast AF unit based on a shooting scene determined by the determination unit;
You may make it change the lens position of the focus lens which detects AF evaluation value by the said contrast AF means according to the sampling interval acquired by the said space | interval acquisition means.

Further, for example, as described in claim 13 , a failure determination unit that determines whether or not the focus by the first AF control unit has failed,
The focus control means includes
When the failure determination means determines that the focus by the first AF control means has failed, the pan focus control means may focus on the subject.

Further, for example, as described in claim 14 , a selection unit for selecting one of the focus control by the first pan focus control unit and the focus control by the first AF control is provided.
The focus control means includes
The subject may be focused according to the focus control selected by the selection means.

In order to achieve the above object, a program according to the invention described in claim 15 includes an imaging process for imaging a subject,
A moving image imaging control process for controlling imaging of a moving image of a subject by the imaging process;
Determination processing for periodically determining a shooting scene based on a subject image when imaging control of the moving image is performed;
A focus control process for focusing on the subject by changing the lens position of the focus lens in accordance with the shooting scene determined by the determination process and the lens position of the zoom lens ;
And each of the above processes is executed by a computer.

According to the present invention, even when the photographing scene has changed during moving image shooting, can be quickly perform focus on the object, it is possible to image the suits of clean focus video.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings as an example applied to a digital camera.
[First embodiment]
A. Configuration of Digital Camera FIG. 1 is a block diagram showing a schematic electrical configuration of a digital camera 1 that implements the imaging apparatus of the present invention.
The digital camera 1 includes a photographing lens 2 (focus lens 2a, zoom lens 2b), motor drive circuit 3, aperture 4, vertical driver 5, TG (timing generator) 6, CCD 7, sample hold circuit 8, analog-digital converter 9, Color process circuit 10, DMA controller 11, DRAM interface 12, DRAM 13, VRAM controller 14, VRAM 15, digital video encoder 16, image display unit 17, JPEG circuit 18, DSP / CPU 19, key input unit 20, memory 21, strobe drive unit 22, a flash light emitting unit 23, a card I / F 24, and a bus 26, and a memory card 25 detachably attached to a card slot of the digital camera 1 main body is connected to the card I / F 24. .

  The taking lens 2 includes a focus lens 2a, a zoom lens 2b, and the like that are composed of a plurality of lens groups. A motor driving circuit 3 is connected to the photographing lens 2. The motor drive circuit 3 is a focus motor that drives the focus lens 2a and the zoom lens 2b in the optical axis direction, a zoom motor, and a focus motor that drives the focus motor and zoom motor according to control signals sent from the DSP / CPU 19. It is composed of a motor driver and a zoom motor driver (not shown).

The diaphragm 4 includes a drive circuit (not shown), and the drive circuit operates the diaphragm in accordance with a control signal sent from the DSP / CPU 19.
The aperture is a mechanism that controls the amount of light that enters from the photographic lens 2. Exposure can be determined by this diaphragm and electronic shutter.

The CCD 7 is scan-driven by the vertical driver 5 and the TG 6, photoelectrically converts the intensity of light of each color of the RGB value of the subject imaged at a fixed period, and outputs it to the sample hold circuit 8. Further, the CCD 7 also functions as an electronic shutter when a sweep pulse is applied.
The sample and hold circuit 8 samples the analog signal sent from the CCD 7 at a frequency suitable for the resolution of the CCD 7 (for example, correlated double sampling), and outputs the analog signal to the analog-to-digital converter 9. Note that automatic gain adjustment (AGC) may be performed after sampling.
The analog-digital converter 9 converts the sampled analog signal into a digital signal and outputs the digital signal to the color process circuit 10.

The color process circuit 10 performs color process processing including pixel interpolation processing and γ correction processing, and generates a luminance color difference signal (YUV signal) from RGB data.
The DMA controller 11 transfers data between the color process circuit 10 and the DRAM 13 via the DRAM interface 12 without the DSP / CPU 19.

The DRAM interface 12 serves as a signal interface between the DMA controller 11 and the DRAM 13 and a signal interface between the DRAM 13 and the bus 26.
The DRAM 13 is a kind of rewritable semiconductor, is a buffer memory that temporarily stores image data (YUV signal generated by the color process circuit 10) picked up by the CCD 7, and serves as a working memory for the DSP / CPU 19. Is also used.

The VRAM controller 14 is a part that controls data transfer between the VRAM 15 and the bus 26 and between the VRAM 15 and the digital video encoder 16. In short, this is the part that controls the writing of display image data to the VRAM 15 and the reading of the image data from the VRAM 15k.
The VRAM 15 is a so-called video RAM, and is a memory that temporarily stores image data of through images and reproduced images.
The digital video encoder 16 converts the digital signal image data read from the VRAM 15 into an analog signal and sequentially outputs the analog signal at a timing according to the scanning method of the image display unit 17.

  The image display unit 17 displays an image of analog signal image data sent from the digital video encoder 16. The image display unit 17 functions as display means of the present invention.

The key input unit 20 includes a plurality of operation keys such as a shutter button, a zoom key (Wide key, Tele key), a SET key, and a cursor key, and outputs an operation signal according to a user's key operation to the DSP / CPU 19.
The strobe driving unit 22 drives the strobe light emitting unit 23 to flash in accordance with a control signal from the DSP / CPU 19, and the strobe light emitting unit 23 causes the strobe to flash. The DSP / CPU 19 sends a control signal to the strobe drive unit 22 when it is determined that the photographing scene is dark by the luminance component of the output signal of the CCD 7 or a photometric circuit (not shown).

The JPEG circuit 18 is a part that compresses / decompresses JPEG (joint photographic experts group). The JPEG circuit 18 JPEG-compresses image data (YUV signal) stored in the DRAM 13 according to a control signal from the DSP / CPU 19 or JPEG-expands image data recorded on the memory card 25. Movie data shot by the movie shooting process is JPEG compressed / expanded for each frame (motion-JPEG). An MPEG circuit may be provided to perform moving picture experts group (MPEG) compression / decompression on moving image data.
The memory card 25 records the image data compressed by the JPEG circuit 18 in the form of an image file. This memory card 25 functions as recording means of the present invention.

The DSP / CPU 19 is a one-chip microcomputer that controls each part of the digital camera 1 described above. Further, the DSP / CPU 19 includes a clock circuit, which clocks the date and time and functions as a timer.
The memory 21 is a control program necessary for controlling each part of the DSP / CPU 19, that is, a program necessary for various controls including AE and AF. The DSP / CPU 19 operates according to the program, and the DSP / CPU 19 obtains moving image capturing control means, determination means, determination means, optical zoom magnification setting means, optical zoom means, and zoom lens position acquisition according to the present invention. Means, focus control means, pan focus AF control means, contrast AF means, first AF control means, PF position acquisition means, focus position acquisition means, range acquisition means, interval acquisition means, failure determination means, selection means, recording control Functions as a display control means.

The memory 21 (first storage means) stores a pan focus position table.
FIG. 2 shows the contents of the pan focus position table stored in the memory 21. The pan focus position table shows the focus position of the pan focus corresponding to the type of zoom stage and priority focus (of the focus lens 2a). Each lens position is recorded.
As can be seen from FIG. 2, there are a zoom stage 1, a zoom stage 2,..., A zoom stage 7, which divides the lens position of the zoom lens 2b into seven stages, and the lens position of each zoom lens 2b. This stage is shown.
The zoom stage 1 indicates the lens position when the zoom lens 2b is in a state where the zoom is not performed and the zoom is hardly performed. The zoom stage 7 is the lens position of the zoom lens 2b. The lens position indicates the lens position when zooming is almost performed at maximum.

There are three types of priority focus: foreground priority focus, distant view priority focus with full aperture, and distant view priority focus without full aperture.
The focus position of the pan focus is inevitably determined depending on the type of the zoom stage and the priority focus.
For example, when the far-field priority focus with the aperture wide open and the zoom stage is the zoom stage 3, the focus position becomes the depth of field of 2.2 to ∞m.

  The memory 21 also has a storage area A for storing information indicating the type of priority focus for which determination has been confirmed, and a storage area B for storing information indicating the determined zoom stage.

B. Operation of Digital Camera 1 The main operation of the digital camera 1 in the first embodiment will be described with reference to the flowchart of FIG.
When the power of the digital camera 1 is turned on by the user's operation of the key input unit 20, the DSP / CPU 19 starts imaging of the subject by the CCD 7 at a predetermined frame rate (fixed period of 1/30 seconds). AE processing is executed at a focal length corresponding to the lens position of the zoom lens 2b, and image processing such as white balance processing is performed by the color process circuit 10 (step S1).

The DSP / CPU 19 stores image data captured by the CCD 7 at a predetermined frame rate (fixed period of 1/30 seconds) in the DRAM 13 when processing such as exposure and white balance is performed, and then stores the stored image. Data is stored in the VRAM 15 and a so-called through image display is performed in which the captured image data is sequentially displayed on the image display unit 17 via the digital video encoder 16 (step S2).
Then, the DSP / CPU 19 determines whether or not the user has operated the zoom key of the key input unit 20 (step S3). This determination is made based on whether or not an operation signal corresponding to the operation of the zoom key is sent from the key input unit 20.

  If it is determined in step S3 that the zoom key has been operated, in step S4, the zoom lens 2b is driven according to the user's operation of the zoom key (in accordance with the operation signal sent from the key input unit 20), and the process proceeds to step S5. If it is determined in step S3 that the zoom key is not operated, the process proceeds to step S5. For example, when the user operates the Tele key of the zoom key, the zoom lens 2b is driven toward the subject side according to the optical axis direction, and when the Wide key of the zoom key is operated by the user, the zoom lens 2b is zoomed. The lens 2b is driven toward the photographer according to the optical axis direction.

In step S5, the DSP / CPU 19 performs focus processing, that is, focuses on the subject. This focus processing will be described in detail later.
Next, the DSP / CPU 19 determines whether or not the user gives an instruction to start recording a moving image (step S6). This determination is made based on whether or not an operation signal corresponding to pressing of the shutter button is sent from the key input unit 20.
If it is determined in step S6 that there is no instruction to start recording, the process returns to step S1. If it is determined in step S6 that there is an instruction to start recording, the process proceeds to step S7, and the DSP / CPU 19 performs moving image shooting / recording processing. That is, JPEG compression is applied to the frame data of the moving image data captured by the CCD 7 at a predetermined frame rate (fixed cycle of 1/30 seconds) and stored in the buffer memory, and the compressed frame data is sequentially stored in the memory. Recording on the card 25.

Next, the DSP / CPU 19 performs AE processing, AWB (auto white balance) processing, and the like (step S8).
Next, the DSP / CPU 19 determines whether or not the zoom key has been operated by the user (step S9). When the DSP / CPU 19 determines that the zoom key has been operated, the DSP / CPU 19 performs a zoom lens operation according to the user's zoom key operation. 2b is driven (step S10), and the process proceeds to step S11. If it is determined that the zoom key is not operated, the process proceeds to step S11 as it is.
In step S11, the DSP / CPU 19 performs focus processing. As described above, this focus processing will be described later in detail.

Next, the DSP / CPU 19 determines whether to end the recording (step S12). This determination is made when the user gives an instruction to end recording, that is, when an operation signal corresponding to pressing of the shutter button is sent from the key input unit 20, or when the memory card 25 runs out of free space. That is, when the recording capacity becomes full, it is determined that the recording is finished.
If it is determined in step S12 that the recording is not to be ended, the process returns to step S7. If it is determined in step S11 that the recording is to be ended, one Motion-JPEG format moving image file is generated from a plurality of already recorded frame data and stored in the memory. Record on card 25

B-1. Focus Processing Next, focus processing of the digital camera 1 in the first embodiment will be described with reference to the flowcharts of FIGS. 4 and 5.
When the processing proceeds to step S5 and step S11 in FIG. 3, the processing proceeds to step S21 in FIG. 4, and the DSP / CPU 19 determines whether or not one second has elapsed since the priority focus determination processing based on the shooting scene described later is performed. Do. At this time, if the shooting scene determination process has not been performed yet, it is determined that one second has elapsed since the shooting scene determination process was performed.

If it is determined in step S21 that one second has elapsed since the priority focus determination process based on the shooting scene, the DSP / CPU 19 performs the priority focus determination process based on the shooting scene (step S22).
The priority focus determination process based on the shooting scene will be briefly described. The current shooting scene is determined, that is, whether it is ultra-high illumination or ultra-low illumination, whether flicker is detected, whether outdoor or indoor. Then, a determination is made as to whether the aperture is open or not, and based on the determined shooting scene, the type of priority focus (near view priority focus, distant focus priority when the aperture is open, and distant focus priority when the aperture is not open) is determined. .

Specifically, when the process proceeds to step S22 in FIG. 4, the process proceeds to step S41 in FIG. 5, and the DSP / CPU 19 determines whether the illuminance is very high or very low based on the image captured by the CCD 7 immediately before. Make a decision. If it is determined that the illuminance is ultra-high illuminance or ultra-low illuminance, the process proceeds to step S45. The determination of the ultra-high illuminance or the ultra-low illuminance is made based on the amount of charge converted from the light incident on the CCD 7.
If it is determined in step S41 that the illuminance is neither ultra-high illuminance nor ultra-low illuminance, the DSP / CPU 19 determines whether or not flicker has been detected from the captured image captured by the CCD 7 immediately before (step S42). If it is determined that flicker is detected, the process proceeds to step S44. If it is determined that flicker is not detected, the process proceeds to step S43.

In step S42, it is determined that no flicker is detected, and when the process proceeds to step S43, the DSP / CPU 19 determines whether the shooting location is outdoor or indoor. This determination is made based on the AWB process (steps S1 and S8) performed immediately before. More specifically, the color temperature of the light source obtained by the automatic white balance process in the color process circuit 10 immediately before is determined by the sun. If it is determined that the color temperature of the light is outdoor, it is determined that it is outdoors.
If it is determined in step S43 that it is indoor, the process proceeds to step S44. If it is determined in step S43 that it is outdoor, the process proceeds to step S45.

If it is determined in step S42 that flicker has been detected, or if it is determined in step S43 to be indoor, the DSP / CPU 19 determines that the focus is in the foreground (step S44).
On the other hand, if it is determined in step S41 that it is ultra-high illuminance or ultra-low illuminance, if it is determined in step S43 that it is outdoors, the process proceeds to step S45, and it is determined whether or not the aperture is open. This determination is made based on the aperture value determined by the AE process (steps S1 and S8) performed immediately before.
If it is determined in step S45 that the aperture is wide open, the DSP / CPU 19 determines that the far-field priority focus is wide open (step S46). If it is determined that the aperture is not wide open, it is determined that the distant view priority focus is not wide open (step S47). ).
When priority focus determination processing is performed, the process proceeds to step S23 in FIG.

  When proceeding to step S23 in FIG. 4, the DSP / CPU 19 determines whether or not the same priority focus type has been determined three times in succession. That is, it is determined whether or not the determined priority focus type is the third consecutive time. For example, when the foreground priority focus is determined by the priority focus determination process based on the shooting scene, the foreground priority focus is determined in the next determination process, and the foreground priority focus is also determined in the next determination process. It is determined that the same priority focus type has been determined three times in succession.

  Even if the same priority focus type is determined three times in succession, if the same priority focus type is stored in the storage area A, the same priority focus is determined three times in succession. It is not determined that the type of is determined. If the type of priority focus is not stored in the storage area A, it is determined that the same priority focus has been determined three times in succession even if the same priority focus has not been determined three times in succession.

  If it is determined in step S23 that the same priority focus type has not been determined three times in succession, the process proceeds directly to step S25. If it is determined in step S23 that the same priority focus type has been determined three times in succession, The DSP / CPU 19 determines the determined priority focus type and stores information indicating the determined priority focus type in the storage area A of the memory 21 (step S24), that is, the storage area A The information stored in is updated, and the process proceeds to step S25. At this time, if information indicating the type of priority focus is already stored in the storage area A, overwriting is performed.

In step S25, the DSP / CPU 19 determines the zoom stage. In this determination, the zoom stage is determined from the current lens position of the zoom lens 2b. When the lens position of the zoom lens 2b is the lens position when the zoom is almost not performed, it is determined as the zoom stage 1, and the lens position of the zoom lens 2b is fully zoomed. If the lens position is in the closed state, the zoom stage 7 is determined.
Next, the DSP / CPU 19 determines whether or not the determined zoom stage is the same as the zoom stage based on the information stored in the storage area B (step S26). When information indicating the zoom stage is not stored in the storage area B, it is determined that the determined zoom stage is not the same as the zoom stage based on the information stored in the storage area B.

If it is determined in step S26 that the same zoom stage as the zoom stage based on the information stored in the storage area B is determined, the process proceeds to step S28, and if it is determined that the same zoom stage is not determined, the DSP / CPU 19 Information indicating the determined zoom stage is stored in the storage area B of the memory 21 (step S27), that is, the information stored in the storage area B is updated, and the process proceeds to step S28. At this time, if information indicating the zoom stage is already stored in the storage area B, overwriting is performed.
In step S28, the DSP / CPU 19 determines whether or not the storage update of the information indicating the priority focus in step S24, the storage update of the information indicating the zoom stage in step S27, or the storage update of both pieces of information is performed. Judging.

If it is determined in step S28 that the information indicating the priority focus and the zoom stage has been stored and updated, the DSP / CPU 19 stores the type of priority focus based on the information stored in the storage area A and the storage area B. The focus position of the pan focus corresponding to the zoom stage based on the information being acquired is acquired from the pan focus position table of the memory 21 (step S29).
For example, when the priority focus based on the information stored in the storage area A is the distant view priority focus with the aperture wide open, and the zoom stage based on the information stored in the storage area B is the zoom stage 5, the information is acquired. As the focus position of the pan focus, a focus position is acquired such that the depth of field is 3.5 to ∞m.

Then, the DSP / CPU 19 moves the focus lens 2a to the acquired focus position (step S30), and proceeds to step S6 or step S12 in FIG.
On the other hand, if it is determined in step S21 that one second has not elapsed since the priority focus determination process based on the shooting scene has been performed, it is determined in step S28 that information indicating priority focus and zoom stage has not been updated. In such a case, the focus process is terminated without performing the focus process, and the process proceeds to step S6 or step S12 in FIG.

C. As described above, in the first embodiment, during moving image shooting (during moving image shooting and through-image display), priority focus determination processing based on the shooting scene and zoom stage determination are performed every second. Process, and the focus position of the pan focus according to the determined priority focus type and zoom stage is acquired, so that the AF process can be performed quickly and an appropriate focus according to the shooting situation can be obtained. It is possible to capture a moving image with a beautiful focus.
In addition, since the type of priority focus is determined and the focus position of different pan focus is acquired according to the determined priority focus, it is possible to perform focusing according to the shooting situation.
In addition, since the focus position of different pan focus is acquired according to the determined zoom stage, the focus suitable for the current zoom lens position can be performed, and the subject can be focused quickly and accurately.

[Second Embodiment]
Next, a second embodiment will be described.
In the focus processing in the first embodiment, a shooting scene is determined, and a PF operation is performed based on the determined shooting scene. In the second embodiment, a shooting scene is used. And the contrast AF process is performed at the focus position based on the determined shooting scene.

D. Configuration of Digital Camera 1 In the second embodiment, the imaging apparatus of the present invention is realized by using the digital camera 1 having the same configuration as that shown in FIG. A table called a position table is stored. This memory 21 functions as the second storage means of the present invention.
FIG. 6 shows a state of the scan representative position table, and the focus position (sampling point) serving as the scan representative position corresponding to the type of the zoom stage and the priority focus is recorded in the scan representative position table. .
Similarly to the pan focus position table, there are zoom stages from zoom stage 1 to zoom stage 7, and there are three types of priority focus: foreground priority focus, distant view priority focus with full aperture, and distant view priority focus with full aperture not open.

The focus position (AF search point) as the scan representative position is inevitably determined from the table of FIG. 6 depending on the zoom stage and the type of priority focus.
For example, in the case of distant view priority focus with the aperture wide open and the zoom stage is the zoom stage 3, the focus position serving as the scan representative position is a focus with a depth of field of 1.2 m to 2.2 m. The position, the focus position where the depth of field is 1.6 m to 4.6 m, and the focus position where the depth of field is 2.5 m to ∞m are three points. In this example, the focus position serving as the scan representative position is three points. However, as long as there are a plurality of focus positions, two or four points may be used.

  Of the three points serving as the representative scan positions corresponding to the type of priority focus and the zoom stage, the distance between the focus position located in the middle and the focus positions located at both ends thereof is the same. In other words, assuming that the three focus positions serving as the scan representative positions are the focus position 1, the focus position 2, and the focus position 3, and the focus position 2 is located between the focus position 1 and the focus position 3, the focus position 1 The distance between the focus position 2 and the distance between the focus position 2 and the focus position 3 (sampling interval) is the same.

  For example, the three focus positions described above include a focus position where the depth of field is 1.2 m to 2.2 m, and a focus position where the depth of field is 1.6 m to 4.6 m. When the focus position is 2.5 m to ∞ m, the focus position is 1.2 m to 2.2 m and the depth of field is 1. Distance distance from the focus position such that the depth of field is 1.6 m to 4.6 m, focus position where the depth of field is 1.6 m to 4.6 m, and depth of field is 2.5 m to ∞ m. The distance distance from the focus position is the same.

  In addition, this sampling interval may be different depending on the type of zoom stage and priority focus. Further, the search range determined by the focus position serving as the scan representative position may be different depending on the zoom stage and the type of priority focus.

E. Operation of Digital Camera 1 The following describes the focus processing operation of the digital camera 1 according to the second embodiment with reference to the flowcharts of FIGS. The main operation of the digital camera 1 is the same as that in the first embodiment, and the operations from step S51 to step S58 in FIG. 7 are the same as the operations described in the first embodiment, so that the operation is simplified. Explained.

When the process proceeds to step S5 and step S11 in FIG. 3, the process proceeds to step S51 in FIG.
If it is determined in step S51 that one second has elapsed since the priority focus determination process based on the shooting scene, the DSP / CPU 19 performs the priority focus determination process based on the shooting scene (step S52).

Next, the DSP / CPU 19 determines whether or not the same priority focus type has been determined three times consecutively by the priority focus determination process based on the shooting scene (step S53).
If it is determined in step S53 that the same priority focus type has not been determined three times in succession, the process proceeds directly to step S55. If it is determined in step S53 that the same priority focus type has been determined three times in succession, The DSP / CPU 19 determines the type of priority focus determined and stores information indicating the type of priority focus determined in the determination in the storage area A of the memory 21, that is, updates the storage ( The process proceeds to step S54) and step S55.

In step S55, the DSP / CPU 19 determines the zoom stage, and determines whether or not the determined zoom stage is the same as the zoom stage based on the information stored in the storage area B (step S55). S56).
If it is determined in step S56 that the same zoom stage as the zoom stage based on the information stored in the storage area B has been determined, the process proceeds directly to step S58, and if it is determined that the same zoom stage has not been determined, the DSP / CPU 19 The information indicating the determined zoom stage is stored in the storage area B of the memory 21, that is, the storage is updated (step S57), and the process proceeds to step S58.

In step S58, the DSP / CPU 19 determines whether or not the information indicating the priority focus is updated in step S54, the information indicating the zoom stage is updated or the both information is updated in step S57. to decide.
The operations so far (steps S51 to S58) are exactly the same as the operations of the focus processing of the first embodiment, that is, the operations from step S21 to step S28 of FIG. In the embodiment, the following operation is different from the operation in the first embodiment.

  If it is determined in step S58 that the priority focus and zoom stage storage has been updated, the DSP / CPU 19 stores the priority focus type based on the information stored in the storage area A and the storage area B. The three focus positions serving as the scan representative positions corresponding to the zoom stage based on the stored information are acquired from the scan representative position table stored in the memory 21 (step S59).

  When the three focus positions serving as the scan representative positions are acquired, contrast AF processing is started based on the acquired three focus positions (step S60). Here, the contrast AF processing means that the focus lens is driven one by one, the AF evaluation value is detected from the imaging signal that is the CCD output at that time, and the lens is positioned at the lens position where the AF evaluation value peaks. It is to adjust the focus. The AF evaluation value is calculated based on the high frequency component included in the image signal captured by the CCD 7.

Hereinafter, contrast AF processing based on the obtained three focus positions will be described.
FIG. 9 shows the relationship between the position transition of the focus lens 2a that is search-driven by the contrast AF process based on the obtained three focus positions and the AF evaluation value at that time.

  First, the focus lens 2a is moved to a focus position closest to the lens position of the current focus lens 2a among the obtained three focus positions. Here, as shown in FIG. 9, the acquired focus position is the focus position 51, the focus position 52, and the focus position 53, and the current lens position of the focus lens 2a is the lens position 41. Therefore, the lens position 41 The focus lens 2a is moved to the focus position 51 closest to. Then, imaging processing by the CCD 7 is executed at the lens position of the focus lens 2a, and the AF evaluation value at that time is detected. Then, the focus lens 2a is moved to the focus position 52 closest to the lens position of the current focus lens 2a, the imaging process by the CCD 7 is executed at the lens position of the focus lens 2a, and the AF evaluation value at that time is detected. . Then, the focus lens 2a is moved to the final focus position 53, the imaging process by the CCD 7 is executed at the lens position of the focus lens 2a, and the AF evaluation value at that time is detected. That is, AF evaluation values are detected only for the three focus positions acquired as the scan representative positions.

  Further, the amount of movement (one division) of the focus lens 2a in the contrast AF process based on the acquired three focus positions is the distance between the focus position 52 and the focus position 51 in FIG. , The distance between the focus position 53 and the focus position 52. Note that the distance between the focus position 52 and the focus position 51 is equal to the distance between the focus position 53 and the focus position 52.

The amount of movement (one division) of the focus lens 2a is determined based on the three focus positions that are the acquired scan representative positions, but may vary depending on the zoom stage and the type of priority focus. It may be. That is, it is recorded in advance in the scan representative position table so that the sampling interval of the focus lens 2a for detecting the AF evaluation value varies depending on the zoom stage and the focus type.
Further, the lens range (search range) of the lens position of the focus lens 2a for detecting the AF evaluation value in the contrast AF processing based on the acquired three focus positions is also based on the acquired three focus positions serving as the scan representative positions. However, it may be different depending on the zoom stage and the type of priority focus. That is, the search range is recorded in advance in the scan representative position table so that the search range varies depending on the zoom stage and the focus type.

As described above, in the contrast AF process based on the obtained three focus positions, the number of search points is smaller (the search range becomes narrower) than in the conventional continuous contrast AF process, so that the search is quickly performed. AF processing can be performed. Also, AF processing can be performed quickly by setting the sampling interval wider than the sampling interval in the conventional contrast AF processing.
Then, the focus lens 2a is moved to a focus position where the AF evaluation value has a peak among the detected AF evaluation values at the three focus positions. Referring to FIG. 9, the focus position at which the AF evaluation value reaches a peak is the focus position 52, so that the subject can be focused by moving the focus lens 2 a to the focus position 52.

  Returning to the flowchart of FIG. 8, when the contrast AF process based on the three focus positions that are the acquired scan representative positions is started in step S60, the DSP / CPU 19 determines whether or not the contrast AF process currently being performed has failed. Is determined (step S61). As an example in which the AF process fails, there is a case where the lens position of the focus lens 2a at which the AF evaluation value reaches a peak (the peak of the mountain shape) is not detected.

If it is determined in step S61 that the contrast AF process has not failed, the DSP / CPU 19 determines whether or not the contrast AF process has been completed (successful) (step S62). If it is determined that the contrast AF process has not been completed, step S61 is performed. Return to.
If it is determined that the contrast AF processing has not been failed (branch to N in step S61) but has been completed (success) (branch to Y in step S62), that is, AF within the obtained three focus positions. When the focus lens 2a is moved to the focus position where the evaluation value reaches a peak, the process proceeds to step S6 or step S12 in FIG.

  On the other hand, if it is determined that the contrast AF process has failed before it is determined that the contrast AF process is completed (branch to Y in step S61), the process proceeds to step S63, and the DSP / CPU 19 stores it in the storage area A. The focus position of the pan focus is acquired from the pan focus position table of the memory 21 from the zoom stage based on the type of the priority focus based on the information and the information stored in the storage area B (step S63).

Next, the DSP / CPU 19 moves the focus lens 2a to the acquired focus position (step S64), and proceeds to step S6 or step S12 in FIG.
If it is determined in step S51 that one second has not elapsed since the priority focus determination process based on the shooting scene has been performed, it is determined in step S58 that the priority focus and zoom stage storage update has not been performed. In this case, the process proceeds to step S6 or step S12 in FIG.

F. As described above, in the second embodiment, during moving image capturing (during moving image capturing or through-image display), priority focus determination processing based on a captured scene and zoom stage determination are performed every second. Processing is performed, the focus position that is the scan representative position corresponding to the determined priority focus type and zoom stage is acquired, the AF evaluation value of the acquired focus position is detected, and contrast AF processing is performed. A subject can be focused quickly and accurately, and a moving image with a beautiful focus can be captured.

In addition, since the type of priority focus is determined and different scan representative positions are acquired according to the determined type of priority focus, it is possible to focus according to the shooting situation, and to focus on the subject quickly and accurately. can do.
Further, since different scan representative positions are acquired according to the lens position of the current zoom lens 2b, it is possible to perform focusing suitable for the current zoom lens position, and it is possible to focus on the subject quickly and accurately.

The present invention can be modified as follows.
(1) In the scan representative position table, a plurality of focus positions are recorded as scan representative positions corresponding to the lens position of the zoom lens 2b and the determined priority focus, but only one point is recorded. Each focus position may be recorded. That is, as shown in the pan focus position table shown in FIG. 3, the lens position of the zoom lens 2b and the scan representative position corresponding to the determined priority focus are each determined as one point. In this case, the focus lens may be driven to a focus position where the AF evaluation value is highest by driving the focus lens in a narrow range based on the focus position acquired as the scan representative position.

  (2) The scan representative position table records the focus positions that are the three search points, but instead of this, a search range table indicating the search range is provided. In contrast, the contrast AF process may be performed. In this search range table, a search range corresponding to the lens position of the zoom lens 2b and the type of priority focus is recorded in advance. As a method for specifying the search range, it is possible to specify the search range by recording the focus positions at both ends of the search range.

  (3) Instead of the scan representative position table, a sampling interval table showing the sampling interval may be provided. In this sampling interval table, a sampling interval corresponding to the lens position of the zoom lens 2b and the type of priority focus is recorded in advance. In this case, the search range is the same as the search range in the normal contrast AF process, but the sampling interval is larger than the sampling interval in the normal contrast AF process.

  (4) In place of the scan representative position table, the above-described search range table and sampling interval table are provided, and the search range and sampling interval are set according to the current lens position of the zoom lens 2b and the type of priority focus. It may be changed.

  (5) Although a scan representative position table and a pan focus position table are provided in advance, the focus position that becomes the scan representative position and the focus position of the pan focus are obtained by calculation without providing these tables. You may do it.

(6) In the scan representative position table, the three focus positions corresponding to the priority focus type and the lens position of the zoom lens are stored, but the three focus positions corresponding only to the priority focus type are stored. The position may be stored. In other words, the current shooting scene may be determined, and the three focus positions serving as the scan representative positions may be acquired according to the priority focus type based on the determined shooting scene.
Similarly, the pan focus position table may store focus positions corresponding only to the priority focus types.

(7) In both the first embodiment and the second embodiment, the focus process at the time of through image display (step S5 in FIG. 3) and the focus process at the time of moving image shooting (step S11 in FIG. 3). ) Is the same focus process, but the focus process at the time of through image display is the focus process (focus process by pan focus) in the first embodiment, and the focus process at the time of moving image shooting is the above-mentioned focus process. Focus processing (focus processing using contrast AF processing) in the second embodiment may be performed.
Further, the focus processing at the time of displaying a through image and the focus processing at the time of moving image shooting may be reversed.

(8) Further, the focus process at the time of displaying the through image and the focus process at the time of moving image shooting by the user are performed by the focus process in the first embodiment or the focus process in the second embodiment. It may be possible to select whether to perform.
(9) Further, the digital camera 1 in the above embodiment is not limited to the above embodiment, but is a mobile phone with a camera, a PDA with a camera, a personal computer with a camera, an IC recorder with a camera, or a digital video camera. In short, any device that can capture a moving image of a subject may be used.

1 is a block diagram of a digital camera according to an embodiment of the present invention. It is a figure which shows the content of the pan focus position table stored in the memory. 3 is a flowchart showing a main operation of the digital camera 1. 3 is a flowchart illustrating an operation of focus processing in the first embodiment. It is a flowchart which shows the operation | movement of the priority focus determination process based on an imaging | photography scene. FIG. 6 is a diagram showing the contents of a scan representative position table stored in a memory 21. It is a flowchart which shows the operation | movement of the focus process in 2nd Embodiment. It is a flowchart which shows the operation | movement of the focus process in 2nd Embodiment. The relationship between the position transition of the focus lens 2a that is search-driven by the contrast AF process by the focus process in the second embodiment and the AF evaluation value at that time is shown.

Explanation of symbols

1 Digital Camera 2 Shooting Lens 3 Motor Drive Circuit 4 Aperture 5 Vertical Driver 6 TG
7 CCD
8 Sample and Hold Circuit 9 Analog to Digital Converter 10 Color Process Circuit 11 DMA Controller 12 DRAM Interface 13 DRAM
14 VRAM controller 15 VRAM
16 Digital Video Encoder 17 Image Display Unit 18 JPEG Circuit 19 DSP / CPU
20 Key input unit 21 Memory 22 Strobe drive unit 23 Strobe light emitting unit 24 Card I / F
25 memory card 26 bus

Claims (15)

Optical zoom magnification setting means for setting the optical zoom magnification;
Optical zoom means for moving the zoom lens according to the optical zoom magnification set by the optical zoom magnification setting means;
Zoom lens position acquisition means for acquiring a lens position of the zoom lens;
Imaging means for imaging a subject;
Moving image imaging control means for controlling imaging of a moving image of a subject by the imaging means;
A determination unit that periodically determines a shooting scene based on a subject image when imaging control is performed by the moving image imaging control unit;
Focus control means for focusing on the subject by changing the lens position of the focus lens according to the shooting scene determined by the determination means and the lens position of the zoom lens acquired by the zoom lens position acquisition means; ,
A moving image pickup apparatus comprising: The focus control means includes
When the same shooting scene is continuously determined a predetermined number of times by the determination means, the subject is focused by changing the lens position of the focus lens according to the determined shooting scene. The moving image capturing apparatus according to claim 1. Determination means for determining the type of priority focus based on the shooting scene determined by the determination means;
The focus control means includes
3. The moving image pickup apparatus according to claim 1, wherein the subject is focused by changing the lens position of the focus lens in accordance with the type of priority focus determined by the determination unit. The focus control means includes
And a pan-focus control unit configured to focus on a subject by changing a lens position of a focus lens in accordance with a pan-focus position corresponding to a shooting scene determined by the determination unit. Item 4. The moving image imaging device according to any one of Items 1 to 3 . The pan focus control means includes
PF position acquisition means for acquiring a focus position of pan focus based on the shooting scene determined by the determination means,
5. The moving image pickup apparatus according to claim 4, wherein the subject is focused by changing the lens position of the focus lens in accordance with the focus position of the pan focus acquired by the PF position acquisition means. First storage means for storing in advance the focus position of the pan focus corresponding to the shooting scene;
The PF position acquisition means includes
6. The moving image capturing apparatus according to claim 5 , wherein a focus position of pan focus is acquired from the first storage unit based on a shooting scene determined by the determination unit. While changing the lens position of the focus lens, the AF evaluation value of the captured image captured by the moving image capturing control unit is detected, and the focus lens is moved to the focus lens position based on the detected plurality of AF evaluation values. Contrast AF means,
The focus control means includes
In accordance with the shooting scene determined by the determining unit, the lens position of the focus lens that detects the AF evaluation value of the captured image captured by the moving image capturing control unit is changed by the contrast AF unit, and the subject is changed. video imaging apparatus according to any one of claims 1 to 6, characterized in that it comprises a first AF control means for performing focus. The first AF control means includes
A focus position acquisition unit that acquires a plurality of focus positions based on the shooting scene determined by the determination unit;
8. The moving image pickup apparatus according to claim 7 , wherein a lens position of a focus lens that detects an AF evaluation value by the contrast AF unit is limited to a plurality of focus positions acquired by the focus position acquisition unit. 9. The moving image pickup apparatus according to claim 8, wherein the plurality of focus positions acquired by the focus position acquisition unit have a constant sampling interval. A second storage means for storing in advance a plurality of focus positions corresponding to the shooting scene;
The focus position acquisition means includes
The moving image imaging apparatus according to claim 8 or 9 , wherein a plurality of focus positions are acquired from the second storage unit based on a shooting scene determined by the determination unit. The first AF control means includes
A range acquisition unit for acquiring a lens range of a lens position of a focus lens for detecting an AF evaluation value by the contrast AF unit based on a shooting scene determined by the determination unit;
8. The moving image pickup according to claim 7 , wherein a lens position of a focus lens for detecting an AF evaluation value by the contrast AF means is limited to a lens range of the lens position of the focus lens acquired by the range acquisition means. apparatus. The first AF control means includes
An interval acquisition unit that acquires a sampling interval of a lens position of a focus lens that detects an AF evaluation value by the contrast AF unit based on a shooting scene determined by the determination unit;
8. The moving image pickup apparatus according to claim 7 , wherein a lens position of a focus lens that detects an AF evaluation value by the contrast AF unit is changed according to a sampling interval acquired by the interval acquisition unit. A failure determination means for determining whether or not the focus by the first AF control means has failed;
The focus control means includes
If it is determined that the focus by the first AF control unit by the failure determining means fails, one of claims 7 to 12, characterized in that performing the focus on the object by the pan-focus control means The moving image imaging device described in 1. A selection means for selecting one of focus control by the first pan focus control means and focus control by the first AF control;
The focus control means includes
Video imaging apparatus according to any one of claims 7 to 13, characterized by performing the focus on the object in accordance with the focus control which is selected by the selection unit. Imaging processing for imaging a subject;
A moving image imaging control process for controlling imaging of a moving image of a subject by the imaging process;
Determination processing for periodically determining a shooting scene based on a subject image when imaging control of the moving image is performed;
A focus control process for focusing on the subject by changing the lens position of the focus lens in accordance with the shooting scene determined by the determination process and the lens position of the zoom lens ;
A program characterized by causing a computer to execute the processes described above.

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