JP2002072074A - Automatic focusing device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide automatic focusing device and method by which high-speed focusing processing is realized by deciding a lens driving direction at the time of focusing in accordance with photographing circumstances. SOLUTION: This device performs AF search action to obtain an evaluated value in accordance with a contrast component from an image signal obtained from a CCD 52 for every position by moving a focus lens 48 with the half- depressing operation of a shutter button 18. At this time, a focus position and a zoom position at the time of starting AF action are detected. When the present focus position is on a short distance side in a focusing area, a search direction is decided on a direction where the lens goes toward infinity from a close range, and when the present focus position is on a long distance side, it is decided on a direction where it goes toward the close range from the infinity. When the present zoom position is on a wide side, the search direction is decided on the direction where the lens goes toward the infinity from the close range and when the present zoom position is on a telephoto side, it is decided on the direction where it goes toward the close range from the infinity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic focusing apparatus and a method therefor, and more particularly, to detecting a high-frequency component of an image based on an output signal from an image sensor, and using the detection result to perform auto-focusing. The present invention relates to a technique for performing AF) control.

[0002]

2. Description of the Related Art In a video camera which captures an image of a subject and outputs a video signal thereof, the video camera captures an image while moving a focus lens of a photographic optical system which acts on focus adjustment, and extracts a high-frequency component from the output video signal. To calculate an evaluation value for focusing. When the evaluation value increases as a result of the movement of the focus lens, the lens continues to be driven in the same direction, and when the evaluation value decreases with the movement of the lens, it is driven in the opposite direction to search for the peak of the evaluation value. That is, a so-called "hill climbing servo system" is employed.

In a digital still camera,
A “contrast AF method” is employed in which a focus lens is driven from a point close to an object to infinity and the focus lens is driven and focused where the evaluation value is maximized. In order to detect the in-focus state from the result of obtaining the evaluation value, it is determined whether or not the contrast is low based on the maximum value and the minimum value of the imaging signal (Japanese Patent Laid-Open No. 6-125).
No. 493) and a device that detects that the evaluation value has continuously decreased to determine a focus position (peak position) (Japanese Unexamined Patent Application Publication No.
000-152065) has been proposed.

[0004]

However, in the case of the hill-climbing servo system, the near side (NEAR side) at the start of the AF operation.
Or, it is not known in which direction to search in the infinity side (FAR side). Conventionally, the lens is slightly moved back and forth (wobbling) and the search direction is determined based on a change in the evaluation value (Japanese Patent Laid-Open No. JP-A-5-34405, JP-A-6-3
39059). Further, in the case of the contrast AF method, at the start of the AF operation, after driving the focus lens to one of the initial positions of close or infinity, the focus lens is driven in the FAR direction or the NEAR direction to obtain an evaluation value. In order to speed up this AF search, it is preferable to start the search from the one with the highest probability that the subject exists.

[0005] The present invention has been made in view of such circumstances, and an automatic focus adjustment device which can perform high-speed focus adjustment by determining a lens moving direction at the time of focus adjustment according to a shooting situation. The aim is to provide a method.

[0006]

According to the present invention, there is provided an automatic camera for adjusting a focal position of a lens for forming an image of a subject on the image pickup means based on an image signal output from the image pickup means. In a focusing device, the device comprises:
Lens moving means for moving the lens within the focus adjustment area, lens position detecting means for detecting the position of the lens, and extracting a contrast component of the subject from an image signal output from the imaging means; Evaluation value calculation means for calculating an evaluation value corresponding to each of the lens movement positions, and direction determination for determining a lens movement direction during a focus adjustment operation based on a current lens position detected by the lens position detection means. Means for controlling the lens movement for obtaining the evaluation value in accordance with the determination of the direction determining means, and moving the lens to a position where the evaluation value becomes a peak to obtain a focused state. And control means for controlling the means.

According to the present invention, the current position of a lens (hereinafter, referred to as a focus lens) for performing focus adjustment is detected, and the AF operation is performed based on where the current focus lens position is located within the focus adjustment area. The search direction is determined. As a result, it is possible to move to the position (search start position) at which the operation of acquiring the evaluation value is started in a short time, and to achieve a high-speed focus adjustment operation.

In one embodiment of the present invention, the direction determining means sets a switching position for dividing the focus adjustment region into two regions, a short distance region and a long distance region, and sets a current lens position and the switching position. When the current lens position is in the short distance area, the acquisition start position of the evaluation value is set to the closest side, and the lens moving direction when acquiring the evaluation value is changed from the closest to infinity. On the other hand, when the current lens position is in the distant area, the acquisition start position of the evaluation value is set to the infinity side, and the lens movement direction when acquiring the evaluation value is from infinity. It is characterized in that it is determined in the direction toward the closest.

The switching position may be a fixed position such as an intermediate position in the focus adjustment area, or, if a variable focal length lens such as a zoom lens is applied, according to the focal length. The switching position may be shifted.

According to another aspect of the present invention, there is provided an automatic focusing apparatus, comprising: a lens moving means for moving a lens within a focusing area; a zoom means for changing a photographing magnification; and a zoom for detecting a zoom position by the zoom means. A position detection unit, an evaluation value calculation unit that extracts a contrast component of the subject from an image signal output from the imaging unit, and calculates an evaluation value corresponding to the contrast component for each movement position of the lens; Direction determining means for determining a lens moving direction during a focus adjustment operation based on the current zoom position detected by the zoom position detecting means, and controlling lens movement for obtaining the evaluation value in accordance with the determination by the direction determining means And controlling the lens moving means to move the lens to a position where the evaluation value reaches a peak to obtain a focused state. It is characterized by comprising a means.

The zoom means may be an optical zoom means for changing the focal length continuously or stepwise by an optical zoom lens, or may electronically process an image signal obtained via an image pickup means. Electronic zoom means for changing the image magnification of the subject according to the conditions.

According to one aspect of the direction determining means in this aspect, when the current zoom position is on the wide side, the acquisition start position of the evaluation value is set to the closest side, and the lens moving direction moves from the closest to infinity. While the direction is determined, when the current zoom position is on the telephoto side, the acquisition start position of the evaluation value is set to the infinity side, and the lens moving direction is determined to be a direction from infinity to the closest.

[0013] In another aspect, the lens moving direction during the focus adjustment operation is determined based on the current lens position (ie, focus position) obtained from the lens position detecting means and the current zoom position obtained from the zoom position detecting means. preferable. In this case, there is a mode in which a table that defines a lens moving direction corresponding to a combination of a focus position and a zoom position is used.

Further, in order to provide an automatic focusing method which achieves the above-mentioned object, the present invention provides a method for adjusting a focal position of a lens for forming an image of a subject on the image pickup means based on an image signal outputted from the image pickup means. In the automatic focusing method for adjusting, the method includes a lens moving step of moving the lens within a focusing area, a lens position detecting step of detecting a position of the lens, and an image signal output from the imaging unit. An evaluation value calculating step of extracting a contrast component of the subject and calculating an evaluation value corresponding to the contrast component for each moving position of the lens; and focusing on a current lens position detected by the lens position detecting means. A direction determining step of determining a lens moving direction during the adjusting operation, and controlling a lens movement for obtaining the evaluation value according to the determination of the direction determining step Controlling the lens moving means such that the lens is moved to a position where the evaluation value reaches a peak to obtain a focused state based on the evaluation value obtained in the evaluation value obtaining control step and the evaluation value obtaining control step. And a controlling step.

According to an automatic focus adjustment method according to another aspect of the present invention, a lens moving step of moving the lens within a focus adjustment area, and a zoom position detection for detecting a zoom position by zoom means for changing a photographing magnification. An evaluation value calculating step of extracting a contrast component of the subject from an image signal output from the imaging unit, and calculating an evaluation value corresponding to the contrast component for each moving position of the lens; A direction determining step of determining a lens moving direction at the time of a focus adjustment operation based on the current zoom position detected by the detecting means, and an evaluation value controlling lens movement for obtaining the evaluation value according to the determination of the direction determining means The lens is moved to a position where the evaluation value reaches a peak based on the evaluation value obtained in the obtaining control step and the evaluation value obtaining control step. It is characterized in that it comprises a controlling process of controlling the lens moving means so as to obtain a state, the.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an automatic focusing apparatus and method according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an external view of a digital camera to which the present invention is applied. A photographing lens 12, a finder window 14, and a strobe light emitting unit 16 are provided on the front of the digital camera 10, and a shutter button 18 and a power switch 20 are provided on the top of the camera. Also,
A card slot 26 for mounting a memory card 24 is provided on the side of the camera opposite to the grip portion 22.

A zoom lens is applied to the taking lens 12, and a CCD image sensor (not shown in FIG. 1 and denoted by reference numeral 52 in FIG. 3) is arranged behind the taking lens 12. The shutter button 18 is configured in a two-stage manner, and in a state of “half-pressing” in which the shutter button 18 is lightly pressed and stopped, the automatic focusing (AF) and the automatic exposure control (AE) operate to lock the AF and AE, and “ Shooting is performed in a state of “full press” from “half press” to further press.

The power switch 20 is also used as a mode change switch, and has an "OFF position" at which the power is turned off,
"Shooting ON position" which is turned on in still image shooting mode,
And the "reproduction ON position" which is turned on in the reproduction mode.
The position can be switched. It should be noted that instead of the power switch (hereinafter, referred to as a power / mode switch) 20 as in this example, a power switch for only power ON / OFF, and a mode switching means such as a mode dial for switching between a still image shooting mode and a reproduction mode. May be provided.

FIG. 2 is an external view of the back side of the digital camera 10. On the back of the digital camera 10, a finder 28, a liquid crystal monitor 30, a zoom switch 32, a multifunctional cross button 34, an AE lock button 36, a menu key 38, an execution key 40, and a cancel key 42 are provided. The liquid crystal monitor 30 is a display means that can be used as an electronic finder for confirming the angle of view during photographing, and can display a preview image of a photographed image, a reproduced image read from the memory card 24, and the like. Selection of menus using the cross button 34 and setting of various items in each menu are also performed using the display screen of the liquid crystal monitor 30.

The zoom switch 32 is composed of a lever switch that can be operated in the up and down direction. The switch is operated to perform a zoom movement in the telephoto (TELE) direction by operating the switch upward and to the wide angle (WIDE) by operating the switch downward. ) Zoom in the direction. The cross button 34 is pressed in one of four directions (up, down, left,
The right button allows the user to input instructions, and is used as an operation button to select various setting items on the menu screen or to change the settings, and to adjust the electronic zoom magnification and to forward / return the playback frame. It is used as an instruction means.

The menu key 38 is used to make a transition from the normal screen of each mode to the menu screen. The execution key 40 is used, for example, when confirming the selected contents or instructing execution (confirmation) of processing. The cancel key 42 is used to cancel (cancel) an item selected from the menu or to return to the previous operation state.

The photographer operates the zoom switch 32 to determine the angle of view while checking the real-time image (through image) displayed on the viewfinder 28 or the liquid crystal monitor 30, and presses the shutter button 18 to perform photographing. .

FIG. 3 is a block diagram showing the internal configuration of the digital camera 10. The taking lens 12 includes a four-group inner-focus zoom lens including a fixed lens 44, a variable power lens 46A, a correction lens 46B, and a focus lens 48.

The zoom lens 46A and the correction lens 46B
The camera moves along the optical axis while the positional relationship between the two is regulated by a cam mechanism (not shown), and changes the focal length. In addition,
For convenience of description, a variable power optical system including a variable power lens 46A and a correction lens 46B will be referred to as a "zoom lens 46".

The light that has passed through the taking lens 12 is
After the light amount is adjusted, the light enters a CCD image sensor (hereinafter, referred to as CCD) 52. Photosensors are arranged in a plane on the light receiving surface of the CCD 52, and the subject image formed on the light receiving surface of the CCD 52 via the photographing lens 12 has a signal charge corresponding to the amount of incident light by each photosensor. Is converted to Note that the CCD 52 controls the charge accumulation time (shutter speed) of each photosensor by the timing of the shutter gate pulse.
It has a so-called electronic shutter function.

The signal charge stored in each photo sensor is
The signals are sequentially read out as voltage signals (image signals) corresponding to the signal charges based on the pulses supplied from the CCD driver 54. The image signal output from the CCD 52 is sent to the analog processing unit 56. The analog processing unit 56 includes a signal processing circuit such as a sampling hold circuit, a color separation circuit, and a gain adjustment circuit. In the analog processing unit 56, correlated double sampling (CDS) processing,
Each of the G and B color signals is subjected to color separation processing, and the signal level of each color signal is adjusted (pre-white balance processing).

The signal output from the analog processing section 56 is converted into a digital signal by the A / D converter 58 and stored in the memory 60. The timing generator (TG) 62 gives a timing signal to the CCD driver 54, the analog processing unit 56, and the A / D converter 58 in accordance with a command from the CPU 64, and the circuits are synchronized by the timing signal. .

The data stored in the memory 60 is transmitted to the bus 6
6 to the signal processing section 68. Signal processing unit 68
Is a digital signal processor (D) including a luminance / color difference signal generation circuit, a gamma correction circuit, a sharpness correction circuit, a contrast correction circuit, a white balance correction circuit, and the like.
SP), and processes an image signal in accordance with a command from the CPU 64.

The image data input to the signal processing unit 68 includes a luminance signal (Y signal) and a color difference signal (Cr, Cb signal).
After being converted to, and subjected to predetermined processing such as gamma correction, the data is stored in the memory 60. When displaying the captured image, the image data is read from the memory 60,
The data is transferred to the display memory 70. The data stored in the display memory 70 is a signal of a predetermined system for display (for example,
After being converted to an NTSC color composite video signal)
The data is output to the liquid crystal monitor (LCD) 30 via the D / A converter 72. Thus, the image content of the image data is displayed on the screen of the liquid crystal monitor 30.

The image data in the memory 60 is periodically rewritten by the image signal output from the CCD 52,
The video signal generated from the image data is transmitted to the liquid crystal monitor 3
By being supplied to 0, an image input via the CCD 52 is displayed on the liquid crystal monitor 30 in real time.
The photographer can check the photographing angle of view using the image (through image) displayed on the liquid crystal monitor 30 or the optical viewfinder 28.

When the photographer operates the zoom switch 32, an instruction signal is input to the CPU 64, and the CPU 64
Controls the zoom drive unit 74 based on the signal from the zoom switch 32 to move the zoom lens 46 in the tele (TELE) direction or the wide (WIDE) direction. Zoom drive 7
Reference numeral 4 includes a motor (not shown), and the zoom lens 46 is driven by the driving force of the motor. The position (zoom position) of the zoom lens 46 is detected by a zoom position sensor 76, and a detection signal from the sensor 76 is input to the CPU 64.

Similarly, the focus drive unit 78 includes a motor (not shown), and the focus lens 48 moves back and forth along the optical axis by the driving force of the motor. The position of the focus lens 48 (focus position) is detected by a focus position sensor 80, and the detection signal of the sensor 80 is C
It is input to PU64.

When the still image shooting mode is set by the power / mode switch 20 and the shutter button 18 is pressed, a shooting start instruction (release ON) signal is issued. The CPU 64 detects a release ON signal and executes an imaging operation for recording. That is, the CPU 64 controls the focus driving unit 7 based on a result of an evaluation value calculation described later.
8 is controlled to move the focus lens 48 to the in-focus position, and the exposure control is performed by controlling the aperture diameter of the diaphragm 50 and the electronic shutter of the CCD 52. Also,
The CPU 64 sends a command to the flash control circuit 82 as necessary to control the light emission of the flash light emitting unit 16.

In this manner, in response to the pressing operation of the shutter button 18, the capture of the image data for recording is started. When the mode for compressing and recording image data is selected, the CPU 64 sends a command to the compression / expansion circuit 84. The compression / expansion circuit 84 compresses the image data taken into the memory 60 according to JPEG or another predetermined format.

The compressed image data is recorded on the memory card 24 via the card interface 86.
Mode for recording uncompressed image data (uncompressed mode)
Is selected, the compression processing by the compression / expansion circuit 84 is omitted, and the image data is recorded on the memory card 24 without being compressed.

In the digital camera 10 of this embodiment, for example, smart media (So
lid-State Floppy Disk Card) is applied. The form of the recording medium is not limited to this, and may be a PC card, a compact flash, a magnetic disk, an optical disk, a magneto-optical disk, a memory stick, or the like, and may be read / written according to an electronic, magnetic, optical, or a combination thereof. Various possible media can be used. Signal processing means and interfaces corresponding to the medium used are applied. A configuration may be adopted in which a plurality of media can be mounted irrespective of different types or the same type of recording media. The means for storing the image file is not limited to a removable medium that can be attached to and detached from the camera body, but may be a recording medium (internal memory) built in the digital camera 10.

When the reproduction mode is set by the power / mode switch 20, an image file is read from the memory card 24. The read image data is expanded by a compression / expansion circuit 84 as necessary, and output to the liquid crystal monitor 30 via the display memory 70.

The CPU 64 is a control section for controlling the circuits of the camera system. The CPU 64 controls the operation of the corresponding circuits based on input signals received from the power / mode switch 20, the shutter button 18, the zoom switch 32, and other operation units, and controls display on the liquid crystal monitor 30, auto focus (AF). Control and automatic exposure (AE) control are performed.

Here, the auto focus control will be described. The image signal converted into a digital signal by the A / D converter 58 is input to the evaluation value calculation unit 88. The evaluation value calculation unit 88 includes a high frequency component extraction circuit 90 and an integration circuit 9
2, the G component data of the input image signal is sampled, and the AF detection target area (reference numeral 94 in FIG. 4) is used.
Hereinafter, it is referred to as a focus area. ), The absolute value of the high-frequency component is extracted, and the absolute value data is integrated in the focus area 94, and a value (corresponding to an evaluation value) obtained by integrating the absolute value data is provided to the CPU 64.

The target area for AF detection does not need to be the entire image area. As shown in FIG. 4, a partial area at the center of the image is set as the focus area 94. During the AF operation, the CPU 64
While moving 8 from infinity to near (or from close to infinity) in the focus adjustment area, the contrast of the center of the image is detected at a plurality of AF detection points (search points), and the evaluation value is calculated. Then, the evaluation value calculated at each point is integrated, the lens position at which the evaluation value becomes the maximum is determined as the in-focus position, and the focus driving unit 78 is moved to move the focus lens 48 to the obtained in-focus position.
Control.

As the focal length of the photographing lens 12 becomes longer and the aperture diameter of the diaphragm 50 becomes larger, the depth of field becomes shallower, and the amount of lens drive from infinity to close distance increases. FIG. 5 shows the relationship between the focal length of the photographing lens 12 and the focus adjustment area 300. FIG. 3 shows an example of the photographing lens 12 in which the focal length can be changed stepwise from 7 mm to 21 mm. As the focal length of the photographing lens 12 increases, the focus adjustment area 300 of the focus lens 48 increases. For example, focal length 7m
In the case of m, the movable range of the focus lens 48 from infinity to the closest distance is 8.17 μm and the focal length is 21 mm
In this case, the focus adjustment area 300 is 735 μm.

The CPU 64 has an AF step width 302 indicating the width of the lens position (search point) for calculating the evaluation value and the number of steps (detection) in accordance with the focus adjustment area 300 which varies according to the focal length of the photographing lens 12. Points).

The number of focus steps may be such that the focus adjustment area 300 at each focal length is equally divided by the AF step width 302 or the AF step width 30 on the short distance (closest limit) side.
2 may be set to be shorter than the infinity side, to increase the number of search points on the short distance side, and to increase the focus accuracy.

As shown in FIG. 5, as the focal length of the taking lens 12 becomes longer, the focus adjustment area 300 becomes wider, and it becomes difficult to determine where the subject is in that area. Therefore, in the present embodiment, as shown in FIG.
The initial position and search direction of the AF search are changed according to the relationship between the current focus position and the focus adjustment area 300. That is, as shown in FIG. 9A, when the current position is farther than the intermediate position M of the focus adjustment area 300, first, the focus driving is performed at infinity, and the AF is performed from infinity to the closest distance. The search is executed to obtain evaluation values at each point. In the example of FIG. 7A, the evaluation value gradually increases with the focus movement by the AF search operation in the closest direction (NEAR direction). Eventually, the evaluation value starts to decrease beyond the peak of the evaluation value, and when a predetermined condition is satisfied, A
The F search is interrupted. Then, the focus lens 48 is moved to a focus position (focus position) corresponding to the detected peak position to obtain a focus state.

Conversely, as shown in FIG. 6B, when the current focus position is closer to the intermediate position M than the intermediate position M, first, the focus drive is performed to the closest position, and the focus is moved from the closest limit to infinity. Then, an AF search is performed to obtain an evaluation value at each point. According to FIG. 3B, the direction of infinity (FAR
The evaluation value gradually rises with the focus movement by the search operation toward (direction), and the evaluation value turns to decrease beyond the peak, and when a predetermined condition is satisfied, the AF search is interrupted. Then, the focus lens is moved to a focus position (focus position) corresponding to the detected peak position to obtain a focused state.

As described above, since the AF search direction is automatically selected according to the current focus position, the average time for driving the focus lens 48 to the search start position (initial position) can be reduced. When the shutter button 18 is continuously pressed halfway, the subject distance rarely changes significantly during this time, and the AF search time during repetition becomes faster.

FIG. 7 shows a flowchart of the AF control.
When the AF process is started by half-pressing the shutter button 18, the CPU 64 first sets the focus area 94 (step S110). For example, the shooting screen is divided into 64 blocks of 8 × 8 with the same area, and a plurality of predetermined blocks at the center are set as the focus area 94 to be evaluated.

Next, the state of the "peak presence flag" is cleared, and the peak presence flag = OFF is set as an initial setting (step S112). After that, shooting lens 1
2, the current value of the focal length, ie, the current zoom position (ZO
OMPOS) information is acquired (step S114). After step S114, the process proceeds to step S116, where arithmetic processing for determining an initial position of the AF search is performed. In addition,
The details of the focus lens initial position calculation processing will be described later with reference to FIG.

The focus lens 48 is moved to the initial position according to the result of the focus lens initial position calculation processing in step S116 in FIG. 7 (step S11).
8).

In the following step S 120, an evaluation value at the current focus stage (search point) is calculated, and the obtained evaluation value is input to CPU 64. CPU
Reference numeral 64 stores the evaluation value at the search point in a memory (not shown).

Then, the process proceeds to a step S122, wherein a process for determining whether or not to suspend the AF search operation is performed. The contents of the interruption determination processing will be described later with reference to FIG. Based on the result of the interruption determination process in step S122 of FIG.
The CPU 64 determines whether to continue / stop the AF search operation (step S124). In the case of “continue”, the process proceeds to step S126, and it is determined whether or not the focus lens 48 has reached the position of the last stage of the search point.

If the determination in step S126 is NO, the process proceeds to step S128, in which the focus lens 48 is moved by one search step (AF step width 302) from the current focus stage, and the process returns to step S120. . In this manner, the evaluation value is moved to the next search point, and the evaluation value is calculated from the frame image data having different focus positions. The processing of steps S120 to S128 is repeated for each point in the focus adjustment area 300, and the evaluation value of each point is sequentially acquired.

In step S126, the focus lens 48
Has reached the position of the last stage, or Step S124
If the determination of "interruption" is obtained in step S13,
Move to 0. In step S130, a position (focus position) at which the maximum evaluation value is obtained is obtained from the result of the evaluation value obtained at each point, and the focus lens 48 is moved to the focus position. The focus lens 48 is held at the in-focus position until the half-pressed state of the shutter button 18 is released. At the same time, the operation of the evaluation value calculation unit 88 is stopped, and the photographing / recording is permitted (step S1).
32). Thus, the automatic focus adjustment processing ends.

When the photographing and recording permission state is obtained, the CPU
The operation state of the shutter button 18 is confirmed by 64, and in response to the full depression of the shutter button 18, the subject is imaged at the current zoom position and the focused focus position, and image data that has undergone predetermined signal processing is attached. The information is recorded on the memory card 24 together with the information.

FIG. 8 is a flowchart showing the procedure of the initial position calculation process. Step S114 described in FIG.
After that, the process shifts to the subroutine of FIG. 8 as step S116. In the initial position calculation process, first, information on the current focus position (P) is obtained (step S21).
0). Next, after obtaining information on the closest position (N) and the position at infinity (I) defining the focus adjustment area 300 (step S212), the intermediate position M of the focus search range is calculated by the following equation (1).

[0057]

The calculation is performed according to the following equation: M = (I + N) / 2 (1) (step S214).

Then, it is determined whether the current focus position (P) is on the infinity side or the closest side of the intermediate position M (step S216). If the current position is on the infinity side, the process proceeds to step S218. Step S218
In, the focus initial position that is the start position of the AF search is determined to be “infinity”, and the driving direction of the far lens during the AF search is determined to be the direction from infinity to the closest side.

On the other hand, if it is determined in step S216 that the current position is on the close side, the process proceeds to step S220. In step S220, the focus initial position serving as the start position of the AF search is determined to be “closest”,
The driving direction of the far lens at the time of the AF search is defined as the direction from the closest to infinity. In FIG. 8, step S216
It is determined whether “P <M” is true or false. If the current position matches the intermediate position M, the process proceeds to step S220. However, if the current position matches the intermediate position M, the focus The position may be set on the infinity side.

After the focus initial position and the search direction are determined in step S218 or S220,
This subroutine ends, and the process returns to the flowchart of FIG.

Instead of the initial position calculation process described with reference to FIG. 8, a mode in which the focus initial position and the search direction are determined according to the current zoom position is also possible. In a camera equipped with a zoom function, when the shooting distance is considered, the subject is often far from the tele side, and is often closer to the wide side. From this viewpoint, by changing the focus search direction according to the focal length, high-speed focus search can be performed.

FIG. 9 shows an example of the focus search direction at each zoom position. According to the figure, the photographing lens 12 can be stopped at 11 zoom positions from the wide end to the tele end, and the focus search direction is defined for each zoom position. When the current zoom position is in the range from the wide-side zoom position “0” to “4”, the focus initial position is set to the nearest (NEAR), and the search operation is performed from the closest (NEAR) to infinity (FAR). Do. When the current zoom position is in the range of “5” to “10” on the telephoto side, the focus initial position is set to infinity (FAR), and the focus is set to a point close to infinity (FAR) (NEA).
Perform search operation toward R).

A table as shown in FIG. 9 is stored in the nonvolatile memory, and the search direction is determined by referring to the table when the AF search starts. That is, the process proceeds to the subroutine of FIG. 10 as step S116 of FIG.
In step S310, it is also possible to determine the focus initial position and the search direction with reference to the table in FIG. 9 based on the information on the current focal length, and return to the flowchart in FIG.

Next, still another mode of the initial position calculation processing will be described.

In FIG. 6 described above, it is determined whether the current focus position is on the infinity side or on the close side with reference to the middle position M of the focus range. A mode in which the position (switching position) is changed according to the zoom position is also possible. For example, as shown in FIG. 11, the switching position M 'is defined as a position of m% of the entire focus adjustment area starting from infinity, and the switching position coefficient m (%) is determined according to the zoom position. Prepared in advance as a table. Then, the switching position M 'is determined by referring to the table from the current zoom position.

As shown in FIG. 9A, when the current position is on the infinity side from the switching position M ', first, the focus is driven to infinity, and the AF search is executed from infinity to the closest. To obtain an evaluation value at each point.

Conversely, as shown in FIG. 11B, when the current focus position is closer to the switching position M ', first, the focus is driven closer, and then from the closest to infinity. An AF search is executed to obtain an evaluation value at each point.

For example, on the zoom wide side, the intermediate position M (m = 50%) of the focus adjustment area is set to the switching position M ', and as the zoom moves to the tele side, the switching position M' is shifted to the closest side. By doing so, the probability that the focus initial position is on the infinity side is increased as the zoom is closer to the telephoto side. Since it is considered that the subject is often at a long distance when photographing on the tele side, it is highly possible that the peak of the evaluation value can be detected early by starting the AF search from the infinity side. The average time of the AF processing can be further reduced in combination with the AF search interruption processing.

FIG. 12 is a flowchart of a calculation process for determining the initial focus position by changing the switching position M '. Instead of the flowchart described with reference to FIG. 8, the initial position calculation processing shown in FIG. 12 can be applied. According to the figure, first, information on the current focus position (P) is obtained (step S410). Next, after acquiring information on the closest position (N) and the infinity position (I) (step S412), the switching position M 'is calculated by the following equation (2).

[0070]

M ′ = (I + N) × m (2) (step S414). Here, m indicates a switching position coefficient (%).

Then, it is determined whether or not the current focus position (P) is closer to infinity or closer to the switching position M '(step S416). If the current position is on the infinity side, the process proceeds to step S418. In step S418, the focus initial position that is the start position of the AF search is determined to be “infinity”, and the lens driving direction during the AF search is determined to be a direction from infinity to the closest side.

On the other hand, if it is determined in step S416 that the current position is on the close side, the process proceeds to step S420. In step S420, the focus initial position that is the start position of the AF search is determined to be “closest”,
The lens driving direction at the time of the AF search is defined as a direction from the closest to infinity. Step S418 or step S42
When the focus initial position and the search direction are determined by 0, this subroutine is terminated and the process returns to the flowchart of FIG.

As a modification of the embodiment described with reference to FIG. 12, a table as shown in FIG. 13 may be used. According to the figure, regardless of the current focus position at the wide end of the zoom, the AF drive always drives to the NEAR side during the AF search, and
It is set to perform a search operation from AR to infinity (FAR). As a result, NE is always maintained near the wide end.
The AF search is started from the AR side.

In the middle area of the zoom, when the current focus position is on the infinity side from the switching position M 'defined by the switching position coefficient (m), the FAR side and the closer position than the switching position M'. , The AF search is started from the NEAR side, and near the telephoto end, the AF search is always started from the FAR side. As described above, by adopting the method of determining the AF search direction in consideration of the current zoom position and focus position comprehensively, finer control becomes possible.

Next, control contents when the AF search operation is interrupted will be described. FIG. 14 shows an example in which the evaluation value is obtained by the AF search. When there is only one main subject in the focus area 94,
As shown in FIG. 14, only one peak of the evaluation value appears. In this case, the lens position (P) at which the peak is detected is set as the focus position, and the focus lens 48 may be moved here. On the other hand, as shown in FIG. 15, when there are a plurality of subjects in the focus area 94, it is not possible to focus on both subjects, and focus is performed on one of the subjects. There is a need.

FIG. 16 shows an example of an evaluation value acquisition result when a plurality of subjects are present in the focus area 94. As shown in the figure, when there are a plurality of subjects in the focus area 94, there are a plurality of peaks in the evaluation value curve. If one mountain is detected and the AF search is terminated, only one mountain can be detected.
Multiple mountains cannot be detected. For example, in FIG. 16, if the AF search operation is started from the infinity side and the AF search operation is ended when a peak on the infinity side is detected,
Another peak on the close side cannot be detected, and the main subject on the close side cannot be focused.

Also, as another method, A
A method of focusing on the first mountain by starting the F search operation is also conceivable. However, in the case of a high-magnification zoom lens, there are many situations where a subject at a long distance is photographed.
In consideration of speeding up the AF process, it can be said that it is preferable to start the search from the infinity side.

Therefore, in the present embodiment, an efficient AF
In order to realize the search operation, the following ideas have been devised. That is, comparing FIG. 14 with FIG. 16, the graph of FIG.
After the peak of the evaluation value is detected by the search operation, if the evaluation value is further obtained by moving the lens in the same direction, when the focus lens 48 is separated from the peak position P by a certain distance d, the evaluation value decreases to near zero level. Figure 1
When a plurality of subjects are present as shown in FIG. 6, after the first peak is detected, the evaluation value does not fall to near the zero level but starts to increase again.

Focusing on this fact, if the evaluation value at a position separated by a certain distance d from the lens position where the peak of the evaluation value is detected is equal to or less than a predetermined threshold T, it is determined that the subject does not exist beyond that. And finish the AF search,
The focus lens 48 is driven to the first detected peak position.

On the other hand, if the evaluation value at a position separated by a certain distance d from the lens position at which the peak of the evaluation value is detected is a value larger than the predetermined threshold T, another subject may exist ahead of it. Then, the AF search operation in the same direction is continued. Note that the distance d from the peak position P is
It is preferable to set about 10 to 20 times the allowable circle of confusion. If a plurality of peaks are detected by the AF search operation, the closest peak position is determined as the focus position.

By the way, when the subject is dark or the like, noise of the image pickup signal occurs, and as shown in FIG. 17, a situation may occur where the evaluation value does not fall below the threshold value T even with only one peak. However, as can be seen from a comparison between FIG. 17 and FIG. 16, when there is another subject on the closest side (FIG. 16), the evaluation value tends to increase from a position somewhat closer to the nearest side. On the other hand, if the evaluation value does not decrease due to noise or the like (FIG. 17), the evaluation value does not change to an increasing tendency even if the evaluation value is a fixed distance w or more before the closest distance.

Therefore, it is possible to determine whether another subject exists on the close side by determining whether or not the evaluation value is in the increasing direction beyond the certain distance w from the closest. If there is no evaluation value in the increasing direction at a distance more than a certain distance w from the closest distance, it is determined that no subject exists on the close side and A
The F search operation is completed, and focus driving is performed to the lens position where the peak is detected. Note that the fixed distance w is preferably set to be about 5 to 10 times the permissible circle of confusion. FIG.
In the AF search operation in the FAR direction, similarly, if the evaluation value does not tend to increase at a position one point distance w from infinity, it can be determined that the subject exists on infinity.

FIG. 18 is a flowchart of the interruption determination processing. The process proceeds to the subroutine in FIG. 18 as step S122 after step S120 described in FIG. When the interruption determination process is started, first, it is determined whether or not a peak at which the evaluation value changes from increasing to decreasing is detected (step S510). This determination is made based on the state of a “peak presence flag” described later.

If no peak is detected in step S510 (NO determination), the process advances to step S512 to determine whether the evaluation value has decreased. Step S
If a negative determination is obtained in 512, continuation of the evaluation value acquisition process is determined (step S518), and this subroutine is terminated and the process returns to the flowchart of FIG.

If it is detected in step S512 that the evaluation value has decreased, the flow branches to step S514. In step S514, it is determined whether or not the evaluation value before the decrease has been increasing. If a YES determination is obtained in step S514, the "peak presence flag" is set to O.
When it is set to N, the data of the variable P indicating the focus position (peak position) where the peak is detected is updated (step S516). After step S516 or when the determination of NO is obtained in step S514, the process proceeds to step S518 to determine continuation of the evaluation value acquisition process.

When the "peak presence flag" is set to ON, a YES determination is made in step S510. In this case, the process proceeds to step S520, and it is determined whether the search direction is the NEAR direction. When the search direction is the NEAR direction (when YES is determined), it is determined whether or not the current focus position (search point) is closer than a predetermined distance (d) from the peak position P to the nearest side ( Step S522). If the current position is within a predetermined distance d from the peak position P (NO determination), step S52 is performed.
Then, it is determined whether the number of remaining detection points in the search direction is smaller than a predetermined value (w). The predetermined value w is a value corresponding to the distance w described in FIG.

If the number of remaining detection points is equal to or larger than the predetermined value w (NO in step S528), continuation of the evaluation value acquisition process is determined (step S532), and the process returns to the flowchart of FIG. Meanwhile, step S
If a YES determination is obtained in 528, the process advances to step S530 to determine whether the evaluation value has increased.

If an increase in the evaluation value is detected in step S530 (when YES is determined), the flow advances to step S532 to determine continuation of the evaluation value acquisition process (step S53).
2) If the evaluation value has not increased in step S530 (NO determination), the process shifts to step S536 to determine interruption of the evaluation value acquisition process, and returns to the main routine of FIG.

If the current focus position is closer than the predetermined distance d from the peak position P in step S522 (when YES is determined), step S524 is performed.
Branch to In step S524, it is determined whether or not the evaluation value at the current focus position is smaller than a predetermined threshold T.

If the evaluation value is equal to or larger than the threshold value T in step S524 (NO determination), the process proceeds to step S528 in consideration of the possibility that the subject exists closer to the current position.
On the other hand, when the evaluation value is smaller than the threshold value T in step S524 (when YES is determined), it is determined that no subject exists closer to the current position, and interruption of the evaluation value acquisition process is determined ( Step S536).

If the determination in step S520 is NO, that is, if the search direction is the FAR direction, step S520
Proceed to 526. In step S526, it is determined whether the evaluation value has continuously decreased a predetermined number of times. A reference value serving as a criterion for determining the number of continuous reductions is appropriately set in consideration of the depth of field and the like.

If a NO determination is obtained in step S526, the flow advances to step S528, and a determination of interruption or continuation is made in steps S528 to S536 described above. On the other hand, if a YES determination is obtained in step S526, the process advances to step S538 to determine interruption of the evaluation value acquisition process, and the process returns to the flowchart in FIG.

By following the interruption determination processing shown in FIG.
In both the NEAR direction and the FAR direction,
The peak of the evaluation value corresponding to the subject can be detected accurately and at high speed, and the speed of the AF processing can be increased.

Next, a description will be given of a control example capable of achieving a higher speed of the AF processing. As the focal length of the taking lens 12 increases, the focus feed amount (number of pulses) in the focus adjustment area 300 (from infinity to close distance) increases, and AF
The longer time is as described in FIG. Therefore, first, a "rough search" for obtaining an evaluation value is performed in an AF search step in which the focus feed amount is increased, and when an approximate in-focus position is detected by the rough search, a search step in which the focus feed amount is further reduced in an area near the focus position is performed. It is preferable to perform a “detailed search” for acquiring an evaluation value.

FIG. 19 is a conceptual diagram of the rough search and the detailed search. In the figure, it is assumed that the focus feed amount from infinity to close distance is 240 pulses, the number of focus feed pulses during rough search is 20 pulses, and the number of focus feed pulses during detailed search is 2 pulses.

As shown in the figure, first, rough search is started from infinity in the NEAR direction. In the rough search, a search point is changed every 20 pulses, an evaluation value is calculated at each point, and the interruption determination processing as described with reference to FIG. 18 is performed.

When a peak is detected in the rough search and, for example, the interruption of the evaluation value acquisition processing is determined at the position of 100 pulses, the focus is moved to the initial position (Pds) of the detailed search, from which the detailed search is performed in the FAR direction. Be started. In the detailed search, the search point is changed every two pulses, the evaluation value is calculated at each point, and after the peak is detected, if the evaluation value continuously decreases a predetermined number of times, it is determined that the evaluation value acquisition processing is to be interrupted, and the peak position ( The focus lens 48 is driven to the (focus position).

FIG. 20 is a flowchart of the AF control combining the rough search and the detailed search. In the figure, steps S610 to S10 including a rough search portion
Step S628 is the same process as steps S110 to S128 of the flowchart described with reference to FIG. 7, and a description thereof will be omitted. The interruption determination (1) processing in step S622 in FIG. 20 is performed by applying the flowchart of the interruption determination processing described in FIG.

If the determination of "interruption" is obtained in step S624 of FIG. 20, or if the final position of the focus stage has been reached in step S626, the process proceeds to step S640. In step S640, an operation is performed to determine the range of the detailed search based on the result of the rough search. Then, a process of driving the focus lens 48 to the detailed search start position (the detailed search initial position) is performed according to the obtained detailed search range (step S642).

Next, after setting an initial value "0" in the register n of the CPU 64 (step S644), the process proceeds to step S646. In step S646, the evaluation value at the current focus position (search point) is calculated, and the obtained evaluation value is input to the CPU 64. CPU
Reference numeral 64 stores the evaluation value at the search point in a memory (not shown).

Then, the flow advances to step S648 to determine whether or not to suspend the AF search. The content of the “interruption determination (2) process” will be described later with reference to FIG. C
The PU 64 performs the interruption determination (2) processing (Step S648)
It is determined whether the AF search is interrupted or continued based on the result (step S650). "Continue" in step S650
When it is determined that the search point has been reached, the process proceeds to step S652, and it is determined whether the search position has reached the final position.

If a NO determination is obtained in step S625, the flow advances to step S654 to move the focus lens 48 by one step (two pulses) of the AF search step from the current focus position.
Return to 46. In this manner, the evaluation value is moved to the next search point, and the evaluation value is calculated from the frame image data having different focus positions. The processing of steps S646 to S654 is repeated for each point in the detailed search range, and the evaluation value of each search point is obtained.

In step S652, the focus lens 48
Has reached the final position of the search point, or when the determination of “interruption” has been obtained in step S650, the process proceeds to step S660. In step S660, a position at which the evaluation value is maximum is obtained from the result of the evaluation value obtained at each point, and the focus lens 48 is moved to that position (focus position). In this way, the photographing recording is permitted (step S662), and the automatic focus adjustment processing ends.

FIG. 21 shows a flowchart of the interruption determination (2) processing shown in step S648 of FIG. In the interruption determination (2) process, first, the register C
Table value “C” corresponding to the current focal length [ZOOMPOS]
_TABLE ”is set (step S710). This is a process of setting an interruption determination value C as a criterion for determining to suspend the AF search when the evaluation value calculated at each focus stage (search point) continuously decreases. .

The interruption determination value C is set to the same numerical value as the number of focus steps (“4” in the example of FIG. 5) on the short focus side (wide side) or a value close thereto, so that the interruption processing is not substantially performed. Is set to In addition, the interruption determination value C becomes larger as approaching the long focal length side (tele side),
It is set to an integer value of about 50% to 30% of the number of focus steps.

Next, the flow advances to step S712 to determine whether or not the obtained evaluation value has decreased. If the evaluation value has not decreased (NO determination), the continuation of the AF search is determined (step S722), the process exits this subroutine, and returns to the flowchart of FIG.

When it is determined in step S712 that the evaluation value has decreased (when the determination is YES), 1 is added to the value of register n (step S714), and in step S716, the value of register n is reduced. It is determined whether the value of the register C is exceeded. If the value of the register n is equal to or less than the value of the register C (NO determination), the process proceeds to step S722 to determine continuation of the AF search.
It returns to the flowchart of FIG. Thus, the AF search is continued until the evaluation value continuously decreases C times.

If a YES determination is obtained in step S716, that is, if it is detected that the evaluation value has decreased continuously C times, the flow advances to step S718. Step S
At 718, it is determined whether or not the difference between the maximum value (AFmax) and the minimum value (AFmin) of the evaluation values calculated by the detailed search is larger than a predetermined value K. If the difference between the evaluation values is larger than the predetermined value K (when YES is determined), it indicates that there is a predetermined contrast, and thus the interruption of the AF search is determined (step S720). If the difference between the evaluation values is equal to or smaller than the predetermined value K (when NO is determined), the process proceeds to step S722, and continuation of the AF search is determined.

When "interruption" or "continuation" is determined in step S720 or S722, the present subroutine ends, and the flow shifts to step S650 in the flowchart in FIG. Subsequent processing contents are as described in FIG.

In the above embodiment, an example in which the photographing magnification is changed by the optical zoom has been described. However, the present invention is also applicable to a camera that performs a zoom operation by an electronic zoom function instead of or in combination with the optical zoom. Can be applied.

[0111]

As described above, according to the present invention, the lens moving direction at the time of focus adjustment is determined from the relationship between the current position of the lens for performing focus adjustment and the focus adjustment range. It is possible to move to the position where the operation is started (search start position) in a short time, so that the focus adjustment operation can be speeded up.

Further, according to the present invention, since the lens moving direction at the time of focus adjustment is determined according to the current zoom position, the operation of acquiring the evaluation value is started from the one with the highest probability of the existence of the subject. As a result, the focus adjustment operation can be speeded up.

[Brief description of the drawings]

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

FIG. 2 is a rear view of the digital camera shown in FIG. 1;

FIG. 3 is a block diagram showing an internal configuration of the digital camera of the present embodiment.

FIG. 4 is a diagram showing an example of a focus area set at the center of the screen;

FIG. 5 is a diagram showing a change in an AF search step width according to a zoom position and a focus position.

FIG. 6 is a conceptual diagram showing a control example of changing an AF search start position and a search direction according to a focus position at the start of AF.

FIG. 7 is a flowchart showing a control procedure of automatic focus adjustment of the present example

FIG. 8 is a flowchart showing the content of a focus lens initial position calculation process shown in FIG. 7;

FIG. 9 is a chart showing an example of a table for designating an AF search direction according to a zoom position;

10 is a flowchart of an initial position calculation process using the table of FIG.

FIG. 11 is a conceptual diagram showing another example of control for changing an AF search start position and a search direction according to a focus position at the start of AF.

12 is a flowchart of an initial position calculation process for implementing the control example shown in FIG.

FIG. 13 is a table showing an example of a table for specifying an AF search direction according to a zoom position and a focus position.

FIG. 14 is a graph showing an example of an evaluation value that changes as the focus lens moves.

FIG. 15 is a diagram showing a state in which a plurality of subjects are present in a focus area.

FIG. 16 is a graph showing an example of an evaluation value that changes with movement of a focus lens when a plurality of subjects exist.

FIG. 17 is a graph illustrating a phenomenon in which the evaluation value does not decrease due to the influence of noise or the like.

FIG. 18 is a flowchart showing the contents of an interruption determination process shown in FIG. 7;

FIG. 19 is a conceptual diagram of an automatic focus adjustment operation combining a rough search and a detailed search.

FIG. 20 is a flowchart illustrating a control procedure of automatic focus adjustment combining a rough search and a detailed search.

FIG. 21 is a flowchart showing the contents of interruption determination (2) processing shown in FIG. 20;

[Explanation of symbols]

10 digital camera, 12 photographing lens, 46 zoom lens (zoom means), 48 focus lens, 5
2: CCD (imaging means), 64: CPU (control means, direction determining means), 76: zoom position sensor (zoom position detecting means), 78: focus drive section (lens moving means), 80: focus position sensor (lens) Position detecting means), 88 ... Evaluation value calculation unit (Evaluation value calculation means)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/232 G02B 7/11 D // H04N 101: 00 G03B 3/00 A F-term (Reference) 2F112 AB07 BA01 CA02 CA12 FA03 FA21 FA45 2H011 BA33 CA19 CA24 2H044 DA01 DA02 DA04 DC02 DE06 2H051 BA44 BA47 CE14 DA22 EA09 FA48 5C022 AA13 AB28 AB66 AC54 AC69 AC78

Claims (7)

[Claims] 1. An automatic focusing device for adjusting a focal position of a lens that forms an image of a subject on the imaging device based on an image signal output from the imaging device, the device comprising: Lens moving means for moving within the lens; lens position detecting means for detecting the position of the lens; extracting a contrast component of the subject from an image signal output from the imaging means; and evaluating an evaluation value according to the contrast component. Evaluation value calculation means for calculating each movement position of the lens; direction determination means for determining a lens movement direction during a focus adjustment operation based on a current lens position detected by the lens position detection means; Controlling the movement of the lens to obtain the evaluation value according to the determination of the means, and moving the lens to a position where the evaluation value reaches a peak. It was an automatic focusing device, wherein a control means for controlling the lens moving means so as to obtain an in-focus state, further comprising: a. 2. The apparatus according to claim 1, wherein the direction determining unit sets a switching position for dividing the focus adjustment region into two regions, a short distance region and a long distance region, and determines a positional relationship between a current lens position and the switching position. In comparison, when the current lens position is in the short distance area, the acquisition start position of the evaluation value is set to the closest side,
While determining the lens movement direction when obtaining the evaluation value to the direction from the closest to infinity, when the current lens position is in the long distance area, the acquisition start position of the evaluation value is set to infinity. 2. The automatic focusing apparatus according to claim 1, wherein the lens moving direction at the time of acquiring the evaluation value is determined to be a direction from infinity to close distance. 3. An automatic focus adjustment device for adjusting a focal position of a lens for forming an image of a subject on the imaging means based on an image signal output from the imaging means, the apparatus comprising: Lens moving means for moving within the camera; zoom means for changing a photographing magnification; zoom position detecting means for detecting a zoom position by the zoom means; and extracting a contrast component of the subject from an image signal output from the imaging means. Evaluation value calculation means for calculating an evaluation value corresponding to the contrast component for each movement position of the lens; and a lens movement direction during a focus adjustment operation based on a current zoom position detected by the zoom position detection means. A direction determining unit for determining the direction, and controlling the lens movement for acquiring the evaluation value according to the determination by the direction determining unit. Control means for controlling the lens moving means so as to obtain a focused state by moving the lens to a position where the evaluation value reaches a peak. 4. The automatic focus adjustment device according to claim 3, wherein the direction determining means sets the acquisition start position of the evaluation value to the closest side when the current zoom position is on the wide side, and sets the evaluation value to While the lens moving direction at the time of acquisition is determined to be a direction from the closest to infinity, when the current zoom position is on the tele side, the acquisition start position of the evaluation value is set to the infinity side, and the evaluation value is acquired. An automatic focus adjustment device, wherein the moving direction of the lens is determined in a direction from infinity to the closest. 5. The automatic focusing apparatus according to claim 3, wherein said apparatus has lens position detecting means for detecting a position of said lens, and said direction determining means is obtained from said lens position detecting means. An automatic focus adjusting device, wherein the lens moving direction is determined based on a lens position and a zoom position obtained from the zoom position detecting means. 6. An automatic focus adjustment method for adjusting a focal position of a lens for forming an image of a subject on the image pickup means based on an image signal output from an image pickup means, the method comprising: A lens moving step of moving the lens within; a lens position detecting step of detecting a position of the lens; extracting a contrast component of the subject from an image signal output from the imaging unit; and evaluating an evaluation value according to the contrast component. An evaluation value calculating step of calculating for each moving position of the lens; a direction determining step of determining a lens moving direction during a focus adjustment operation based on a current lens position detected by the lens position detecting means; An evaluation value acquisition control step of controlling a lens movement for acquiring the evaluation value in accordance with a process decision; and an evaluation value obtained in the evaluation value acquisition control step Controlling the lens moving means so as to obtain a focused state by moving the lens to a position at which the evaluation value reaches a peak based on the control method. 7. An automatic focus adjustment method for adjusting a focal position of a lens that forms an image of a subject on the imaging unit based on an image signal output from an imaging unit, the method comprising: A lens moving step of moving within the camera; a zoom position detecting step of detecting a zoom position by a zoom unit that changes a photographing magnification; and extracting a contrast component of the subject from an image signal output from the imaging unit. An evaluation value calculating step of calculating an evaluation value corresponding to each of the moving positions of the lens; and determining a direction of determining a lens moving direction during a focus adjustment operation based on a current zoom position detected by the zoom position detecting means. An evaluation value obtaining control step of controlling a lens movement for obtaining the evaluation value according to the determination of the direction determining means; A control step of controlling the lens moving means to move the lens to a position where the evaluation value reaches a peak based on the evaluation value obtained in the value acquisition control step so as to obtain a focused state. Automatic focusing method.