JP5621027B2 - Imaging apparatus and control method thereof - Google Patents

Description

  The present invention relates to an imaging apparatus and a control method thereof, and more particularly to an imaging apparatus that performs automatic focusing control and a control method thereof.

  In automatic focusing (AF) control of a video camera or the like, a TV-AF system that detects a focusing position based on the sharpness (contrast) of a video signal generated using an image sensor is widely used. Specifically, an AF evaluation value indicating the degree of contrast is generated for a video signal obtained by sequentially shooting while moving the focus lens, and the position of the focus lens at which the contrast is maximized is determined based on the AF evaluation value. Search as the in-focus position.

  However, when photographing a person, there is a case where the background is not the person but the background because of the contrast between the person who is the main subject and the contrast of the background.

  In order to solve such a problem, there is known an imaging apparatus that detects a person and sets a focus detection area so that the person is in focus. For example, an imaging device having a face detection function and performing focus detection on a focus detection area including a detected face area (see, for example, Patent Document 1) or detecting a human eye and detecting a focus based on the eye There has been proposed an imaging device (see, for example, Patent Document 2).

JP 2006-227080 A JP 2001-215403 A

  However, in the focus detection using the above-described conventional face detection function, for example, when the person who is the subject suddenly approaches and blurs, the amount of change in the AF evaluation value of the TV-AF method is small, so It takes time to detect the direction of the focus. As a result, focusing takes time, and AF followability sometimes becomes a problem.

  The present invention has been made in view of such a problem of the prior art, and improves the focusing speed in an imaging apparatus that performs TV-AF automatic focusing control using subject information obtained from an image. One of the purposes is to do.

  The above-described object is an imaging device that performs automatic focusing control by driving a focus lens, and based on a detection unit that detects a region of a specific subject from a captured image, and a detection result by the detection unit, Setting means for setting a focus detection area in an area including a specific subject area of the image; and generation means for generating an AF evaluation value based on a predetermined frequency band component included in the focus detection area of the image; And a first determination unit that determines a search direction of the focus lens for searching for a focal point based on the AF evaluation value, and a focus unit based on a change in the size of a specific subject area detected by the detection unit. A second determination unit that determines a search direction of the focus lens for searching for a focal point; and a plurality of positions of the focus lens based on the search direction determined by the first determination unit or the second determination unit. The moved is achieved by an imaging apparatus characterized by comprising a control means for automatic focusing control, a using a plurality of AF evaluation value obtained at a plurality of positions.

  In addition, the above-described object is a method for controlling an imaging apparatus that performs automatic focusing control by driving a focus lens, and includes a detection step for detecting a specific subject area from a captured image, and detection in the detection step. Based on the result, a setting step for setting a focus detection area in an area including a specific subject area of the image, and an AF evaluation value based on a predetermined frequency band component included in the focus detection area of the image A generation step for generating, a first determination step for determining a search direction of a focus lens for searching for a focal point based on the AF evaluation value, and a change in the size of the area of the specific subject detected in the detection step And a second determination step for determining a search direction of the focus lens for searching for a focal point, and a first determination step or a second determination step. And a control step of moving the focus lens to a plurality of positions based on the determined search direction and performing automatic focusing control using a plurality of AF evaluation values obtained at the plurality of positions. This is also achieved by a method for controlling the imaging apparatus.

  With such a configuration, according to the present invention, it is possible to improve the focusing speed in an imaging apparatus that performs TV-AF type automatic focusing control using information on a subject obtained from an image.

1 is a block diagram illustrating a configuration example of a digital video camera 100 as an example of an imaging apparatus according to a first embodiment of the present invention. It is a flowchart which shows the detail of AF control which the control part 114 performs in the 1st Embodiment of this invention. It is a flowchart which shows the detail of the micro drive operation | movement which the control part 114 performs in the 1st Embodiment of this invention. It is a figure which shows the example of the position change of the focus lens 105 during the micro drive operation | movement in the 1st Embodiment of this invention. It is a flowchart which shows the detail of the hill-climbing drive control which the control part 114 performs in the 1st Embodiment of this invention. It is a figure which shows the example of the drive operation | movement of the magnitude | size of AF evaluation value and the focus lens 105 during the hill-climbing drive operation | movement in the 1st Embodiment of this invention.

Hereinafter, exemplary and preferred embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram illustrating a configuration example of a digital video camera 100 as an example of an imaging apparatus according to the first embodiment of the present invention. The present invention can also be applied to digital still cameras, other arbitrary imaging devices having a face detection function and a moving image shooting function, and devices including such imaging devices.

  In FIG. 1, a digital video camera 100 according to this embodiment includes a zoom lens 120 having an autofocus function as an imaging optical system. The zoom lens 120 includes a first fixed lens 101, a variable magnification lens 102 that moves in the optical axis direction and performs variable magnification, a diaphragm 103, a second fixed lens 104, and a focus compensator lens 105. A focus compensator lens (hereinafter simply referred to as a focus lens) 105 has both a function of correcting the movement of the focal plane due to zooming and a focusing function.

  The image sensor 106 is composed of a photoelectric conversion element such as a CCD sensor or a CMOS sensor. The CDS / AGC circuit 107 performs correlated double sampling on the output of the image sensor 106 and adjusts the gain.

  The camera signal processing circuit 108 performs various types of image processing on the output signal from the CDS / AGC circuit 107 to generate a video signal. The display unit 109 is configured by an LCD or the like, and displays a video signal from the camera signal processing circuit 108. The recording unit 115 records the video signal from the camera signal processing circuit 108 on a recording medium (magnetic tape, optical disk, semiconductor memory, etc.).

  The zoom drive circuit 110 moves the variable power lens 102 according to the control of the control unit 114. The focus lens driving circuit 111 moves the focus lens 105 according to the control of the control unit 114. The zoom drive circuit 110 and the focus lens drive circuit 111 are configured by actuators such as a stepping motor, a DC motor, a vibration motor, and a voice coil motor.

  The AF gate 112 outputs only the signal of the region (focus detection region or AF frame) used for focus detection set by the control unit 114 among the output signals of all the pixels from the CDS / AGC circuit 107 in the subsequent AF signal processing circuit. 113.

  The AF signal processing circuit 113 extracts, for example, a predetermined frequency band component, specifically a high-frequency component, by applying a filter to the pixel signal in the focus detection region supplied from the AF gate 112, and AF Generate an evaluation value.

  The AF evaluation value is output to the control unit 114. The AF evaluation value is a value representing the sharpness (contrast level) of the video generated based on the output signal from the image sensor 106, but the sharpness of the focused video is high, and the blurred video Since the sharpness is low, it can be used as a value representing the focus state of the imaging optical system.

  The control unit 114 is, for example, a microcomputer, and controls the entire unit of the digital video camera 100 by executing a control program stored in advance in a ROM (not shown) to control each unit of the digital video camera 100. The control unit 114 controls the focus lens driving circuit 111 based on the AF evaluation value given from the AF signal processing circuit 113 to perform an AF control (automatic focus control) operation. Further, the zoom drive circuit 110 is controlled according to a zoom instruction from the operation unit 117 described later, and the magnification of the zoom lens 120 is changed.

  The face detection unit 116 applies a face detection process based on a known face detection technique to the image signal output from the CDS / AGC circuit 107, and detects a face area as an example of a person area in the image. As a known face detection technique, a method based on learning using a neural network or the like, template matching is used to search a part having a characteristic shape of eyes, nose, mouth, etc. from an image, and if the degree of similarity is high, it is regarded as a face There are methods. In addition, many other methods have been proposed, such as a method that detects image feature amounts such as skin color and eye shape and uses statistical analysis. In general, a plurality of these methods are combined to improve the accuracy of face detection. Specific examples include a face detection method using wavelet transform and image feature amount described in JP-A-2002-251380.

  The face detection unit 116 outputs information that can specify the position and size of an area (face area) detected as a human face in the image, for example, to the control unit 114 as a face detection result. Based on the face detection result, the control unit 114 instructs the AF gate 112 to set a focus detection area in an area including the face area in the image.

  The operation unit 117 is a group of input devices such as switches, buttons, and dials for the user to input various instructions and settings to the digital video camera 100. The operation unit 117 includes a shooting start / pause button, a zoom switch, a still image shooting button, a direction button, a menu button, an execution button, and the like.

Next, details of the AF control performed by the control unit 114 will be described with reference to the flowchart shown in FIG.
In step S202, the control unit 114 performs a minute driving operation, and determines whether the in-focus direction is in the near or near direction if in-focus or not in-focus. Details of the minute driving operation will be described later with reference to FIG.

  In S203, the control unit 114 branches the process according to the determination result in S202. If it is determined that the subject is in focus by the minute driving operation in S202, the control unit 114 advances the process to S209, and if not, advances the process to S204.

  In S204, the control unit 114 further branches the process depending on whether or not the in-focus direction can be determined in S202. That is, if the direction can be determined, the process proceeds to S205, and if not, the process returns to S202 to continue the minute driving operation.

  In step S205, the control unit 114 controls the focus lens drive circuit 111 to drive the focus lens to climb up at a high speed in a direction in which the AF evaluation value increases. Details of the hill-climbing driving operation will be described later with reference to FIG.

  In S206, the control unit 114 determines whether or not the peak of the AF evaluation value has been exceeded in the hill-climbing driving operation in S205. If it is determined that the peak has been exceeded, the process proceeds to S207; otherwise, the hill-climbing driving operation in S205 is continued.

  In S207, the control unit 114 controls the focus lens driving circuit 111 to return the focus lens 105 to the lens position where the AF evaluation value obtained during the hill-climbing driving operation reaches a peak. In S208, the control unit 114 checks whether or not the focus lens 105 has returned to the position where the AF evaluation value is maximized. If it has returned, the process returns to S202 to continue the minute driving operation again, and if it has not returned, the process returns to S207 to continue the operation of returning the position of the focus lens 105.

Next, the focusing operation from S209 will be described.
In step S209, the control unit 114 holds the AF evaluation value from the AF signal processing circuit 113. In S210, the control unit 114 acquires the latest AF evaluation value from the AF signal processing circuit 113. In S211, the control unit 114 compares the AF evaluation value held in S209 with the AF evaluation value newly acquired in S210, and determines whether or not the variation of the AF evaluation value is large. Specifically, if there is a difference of a predetermined value or more in the AF evaluation value, the control unit 114 determines that the fluctuation is large, returns the process to S202, and restarts the micro driving operation. On the other hand, if it is not determined that the variation in the AF evaluation value is large, the control unit 114 controls the focus lens driving circuit 111 to stop the focus lens 105 and returns the process to S210.

Next, the minute driving operation performed in S202 of FIG. 2 will be described using the flowchart shown in FIG.
In step S302, the control unit 114 acquires the latest face detection result. Then, an AF frame (focus detection area) is determined according to whether or not there is a detected face area, and the AF gate 112 is configured to supply only the pixel signal in the determined AF frame to the AF signal processing circuit 113. Set. Further, the control unit 114 acquires the AF evaluation value generated by the AF signal processing circuit 113 based on the pixel signal inside the AF frame.
The control unit 114 also stores the acquired face detection results and AF evaluation values in a predetermined number of times in an internal memory (not shown) or the like.

  In S303, the control unit 114 determines whether or not the AF evaluation value acquired in S302 is greater than the previously acquired AF evaluation value. If the currently acquired AF evaluation value is less than or equal to the previously acquired AF evaluation value, the control unit 114 controls the focus lens driving circuit 111 in S305 to move the focus lens 105 by a predetermined amount in the direction opposite to the previous time.

  On the other hand, if the AF evaluation value acquired this time is larger than the AF evaluation value acquired last time, the control unit 114 controls the focus lens driving circuit 111 in S304 to move the focus lens 105 further by a predetermined amount in the same direction as the previous time. .

FIG. 4 is a diagram illustrating an example of a change in the position of the focus lens 105 during the minute driving operation.
In FIG. 4, the AF evaluation value AF _A generated by the AF signal processing circuit 113 with respect to the focus detection area of the video signal generated by the CDS / AGC circuit 107 based on the electric charge accumulated in the image sensor 106 in the period _A is the time. It is obtained to the control unit 114 at T _a. Thereafter, the focus lens 105 is moved by a predetermined amount in the direction of the arrow a by the minute driving operation, and the AF evaluation value AF _B for the video signal photographed by the image sensor 106 in the period B is acquired by the control unit 114 at time T _B. Is done.

Then, the control unit 114 compares the AF evaluation values AF _A and AF _B. If AF _A <AF _B , the control unit 114 moves the focus lens 105 by a predetermined amount in the forward direction (the same direction as the previous time, that is, the direction of the arrow a). Let On the other hand, if AF _A > AF _B , the focus lens 105 is moved by a predetermined amount in the reverse direction (the direction opposite to the previous time, ie, the direction of the arrow b).

  Note that the amount of movement of the focus lens 105 in S304 and S305 in the minute driving operation is an amount that cannot be determined when the imaging signal is displayed on the display unit 109 or the like when the focus state is changed by one movement. Is preferred. Specifically, it is preferable to set the movement amount so that the position after movement is within the depth of focus.

  In step S306, the control unit 114 determines whether the AF evaluation value determination result in step S303 or the driving direction of the focus lens 105 has not changed continuously a predetermined number of times, that is, the direction determined as the in-focus direction is the predetermined number of times. Check if they are identical. If the direction determined as the in-focus direction has not changed continuously for a predetermined number of times, the control unit determines in S307 that the direction has been determined, and ends the minute driving operation.

  On the other hand, if the direction determined to be the in-focus direction is not the same for a predetermined number of times, the control unit 114 determines whether or not the position of the focus lens 105 has reciprocated a predetermined number of times within the same range in S308. This determination may be a determination as to whether or not the position of the focus lens 105 is within a predetermined range for a predetermined time. If it is determined that any one of the conditions is satisfied, the control unit 114 determines that the in-focus determination has been made in S309, and ends the minute driving operation. If none of the conditions is satisfied in S308, the control unit 114 determines that neither direction determination nor in-focus determination has been performed, and advances the processing to S311.

If neither direction determination nor focus determination is possible, the control unit 114 refers to an AF evaluation value stored in an internal memory (not shown) or the like in S311 to determine whether the AF evaluation value is continuously small for a predetermined time (predetermined number of times). Specifically, it may be determined whether or not the AF evaluation value is not more than a predetermined threshold value Th _AF continuously for a predetermined number of times. The threshold value Th _AF can be set to an arbitrary value corresponding to the AF evaluation value when the subject is out of focus.

If it is determined in S311 that the AF evaluation value is continuously small for a predetermined time, the control unit S12 determines whether or not a face is continuously detected. Here, it is assumed that it is determined whether a face area is continuously detected from the face detection result acquired in S302 and the most recent face detection result. If it is determined that the face area is not continuously detected, the control unit 114 ends the minute driving operation. On the other hand, if it is determined that the face area is continuously detected, the control unit 114 compares the latest face detection result stored in an internal memory (not shown) with the face detection result acquired in S302 in S313. Then, it is determined whether the size of the face area has changed significantly. Specifically, whether the absolute value of the size difference (number of pixels) or ratio (%) of the face area included in the face detection result is equal to or greater than a predetermined threshold Th _f (number of pixels or%). This may be a determination. When the change in the size of the face area is less than the threshold Th _f , the control unit 114 ends the minute driving operation.

  On the other hand, when it is determined that the size of the face area has changed significantly, the control unit 114 determines whether or not the face area has increased (decreased) in S314. Here, when it is determined that the face area is large, it is considered that the subject (person) is approaching. Therefore, in S315, the control unit 114 determines the hill-climbing driving direction executed in S205 as the closest direction, and ends the minute driving operation. On the other hand, when it is determined that the face area is not large (small), it is considered that the subject (person) is moving away. Therefore, in S316, the control unit 114 determines the hill-climbing driving direction as the infinity direction and ends the minute driving operation.

  As described above, in the minute driving operation, when neither in-focus direction determination nor in-focus determination can be performed, the automatic focus control operation is performed according to the moving direction of the subject estimated from the change in the size of the detected face area. The direction of the in-focus point in (the in-focus search direction) is determined. Therefore, it is possible to suppress the number of repetitions of the minute driving operation and shift to the hill-climbing driving operation, and it is possible to improve the AF responsiveness and the focusing speed.

  Next, the hill-climbing driving operation performed in S205 of FIG. 2 will be described using the flowchart shown in FIG. In FIG. 5, steps that perform the same operations as in FIG. 3 are given the same reference numerals as in FIG. 3, and detailed descriptions thereof are omitted.

  In the hill-climbing driving operation, similarly to the minute driving operation, the control unit 114 first acquires the face detection result and sets the AF frame, and acquires the AF evaluation value according to the setting (S302). Next, the control unit 114 evaluates the previously acquired AF evaluation value and the size of the AF evaluation value acquired this time (S303), and branches the process.

  If the AF evaluation value acquired this time is larger than the AF evaluation value acquired last time, the control unit 114 controls the focus lens driving circuit 111 in S504, and drives the focus lens 105 to climb in the same direction (forward direction) as the previous time. That is, it is moved at a predetermined speed, and the process is terminated.

  On the other hand, if the AF evaluation value acquired this time is equal to or less than the previously acquired AF evaluation value, the control unit 114 determines whether the AF evaluation value has decreased beyond the peak in S505. If it is determined that the AF evaluation value has decreased beyond the peak, the control unit 114 proceeds to S506, and ends the process assuming that the peak has been exceeded.

  If it is not determined in step S505 that the AF evaluation value has decreased beyond the peak, the control unit 114 controls the focus lens driving circuit 111 in step S507 to drive the focus lens 105 in a reverse direction to the previous time, that is, a predetermined amount. Move at a speed and finish the process.

FIG. 6 is a diagram illustrating an example of the AF evaluation value size and the driving operation of the focus lens 105 during the hill-climbing driving operation.
In FIG. 6, when the focus lens 105 is driven in the right direction in the figure from the starting position of hill-climbing driving, it is detected that the AF evaluation value decreases beyond the peak (maximum value) as indicated by an arrow A. The In this case, the hill-climbing driving operation is terminated assuming that the focal point has been passed, the focus lens 105 is returned to the position where the maximum AF evaluation value is obtained (FIGS. 2, S207 and S208), and the micro-driving operation is shifted to ( S202).

  On the other hand, when the focus lens 105 is driven to the left in the figure from the starting position of hill-climbing driving, as indicated by an arrow B, it is detected that the AF evaluation value decreases without exceeding the peak. In this case, it is determined that the moving direction of the focus lens 105 is wrong, and the hill-climbing driving operation is continued in the reverse direction. In hill-climbing driving, the amount of movement of the focus lens 105 per fixed time is larger than that during the minute driving operation described above.

  As described above, the control unit 114 repeats the determination of whether or not to restart (restart from minute driving) → minute driving → hill-climbing driving → minute driving → restart determination, and the focus lens 105 is positioned at the position where the AF evaluation value becomes maximum. An AF control operation is performed to move.

  As described above, according to the present embodiment, it is possible to improve the focusing speed in an imaging apparatus that performs TV-AF type automatic focusing control using information on a subject obtained from an image. Specifically, in an imaging apparatus that detects a specific subject from a captured image, sets an AF frame in the detected subject area, and performs automatic focus control, the in-focus search direction cannot be determined from the AF evaluation value. Changes in the size of the subject area are detected. Then, the AF responsiveness and the focusing speed can be increased by determining the in-focus search direction in the focus detection process in accordance with the movement direction of the object estimated based on the change in the size of the object region. .

In the present embodiment, an example in which a human face area is used as an example of a specific subject area has been described. Even if the AF frame is set for an arbitrary subject area, such as another subject or other part of a person, not only the person's face, the direction of movement of the subject based on the change in the size of the subject area The basic concept of the present invention of estimating the in-focus search direction is applicable.
Further, in this embodiment, in order to facilitate understanding of the invention, when the in-focus search direction cannot be determined from the AF evaluation value, the in-focus search direction is determined based on the change in the size of the subject area. Described as what to do. However, as described above, the basic idea of the present invention of estimating the moving direction of the subject based on the change in the size of the subject region and determining the in-focus search direction is based on the AF evaluation value based on the focus point. It is not essential that the search direction cannot be determined.

  In the present embodiment, no particular reference is made to the lower limit of the AF evaluation value in the process for determining whether or not the AF evaluation value is small continuously for a predetermined time. However, if the AF evaluation value is too low and the reliability of face detection cannot be maintained, a threshold for determining the lower limit of the AF evaluation value may be introduced in S311.

Specifically, in S311, if Th _fd <AF evaluation value ≦ Th _AF is satisfied a predetermined number of times (predetermined time), the process may proceed to S312. Th _fd is an AF evaluation value corresponding to the lowest in-focus state that can maintain the reliability of face detection.

(Other embodiments)
The above-described embodiment can also be realized in software by a computer of a system or apparatus (or CPU, MPU, etc.).
Therefore, the computer program itself supplied to the computer in order to implement the above-described embodiment by the computer also realizes the present invention. That is, the computer program itself for realizing the functions of the above-described embodiments is also one aspect of the present invention.

  The computer program for realizing the above-described embodiment may be in any form as long as it can be read by a computer. For example, it can be composed of object code, a program executed by an interpreter, script data supplied to the OS, but is not limited thereto.

  A computer program for realizing the above-described embodiment is supplied to a computer via a storage medium or wired / wireless communication. Examples of the storage medium for supplying the program include a magnetic storage medium such as a flexible disk, a hard disk, and a magnetic tape, an optical / magneto-optical storage medium such as an MO, CD, and DVD, and a nonvolatile semiconductor memory.

  As a computer program supply method using wired / wireless communication, there is a method of using a server on a computer network. In this case, a data file (program file) that can be a computer program forming the present invention is stored in the server. The program file may be an executable format or a source code.

Then, the program file is supplied by downloading to a client computer that has accessed the server. In this case, the program file can be divided into a plurality of segment files, and the segment files can be distributed and arranged on different servers.
That is, a server apparatus that provides a client computer with a program file for realizing the above-described embodiment is also one aspect of the present invention.

  In addition, a storage medium in which the computer program for realizing the above-described embodiment is encrypted and distributed is distributed, and key information for decrypting is supplied to a user who satisfies a predetermined condition, and the user's computer Installation may be allowed. The key information can be supplied by being downloaded from a homepage via the Internet, for example.

Further, the computer program for realizing the above-described embodiment may use an OS function already running on the computer.
Further, a part of the computer program for realizing the above-described embodiment may be configured by firmware such as an expansion board attached to the computer, or may be executed by a CPU provided in the expansion board. Good.

Claims (12)

An imaging device that performs automatic focusing control by driving a focus lens,
Detecting means for detecting a region of a specific subject from the captured image;
Setting means for setting a focus detection area in an area including an area of a specific subject in the image based on a detection result by the detection means;
Generating means for generating an AF evaluation value based on a predetermined frequency band component included in the focus detection region of the image;
First determining means for determining a search direction of the focus lens for searching for a focal point based on the AF evaluation value;
Second determining means for determining a search direction of the focus lens for searching for a focal point based on a change in the size of the area of the specific subject detected by the detecting means;
The focus lens is moved to a plurality of positions based on the search direction determined by the first determination means or the second determination means, and automatically using the plurality of AF evaluation values obtained at the plurality of positions. Control means for performing focusing control ,
The control means moves the focus lens to a plurality of positions based on the search direction determined by the second determination means when the AF evaluation value is smaller than a predetermined value, and obtains the plurality of positions at the plurality of positions. Performing the automatic focusing control using the plurality of AF evaluation values obtained,
The control means moves the focus lens to a plurality of positions based on the search direction determined by the first determination means when the AF evaluation value is equal to or greater than the predetermined value, and obtains the plurality of positions at the plurality of positions. An image pickup apparatus that performs the automatic focusing control using the plurality of AF evaluation values obtained .   The control means moves the focus lens to a plurality of positions based on the search direction determined by the second determination means when the change in size of the subject is a predetermined value or more, and the plurality of positions The imaging apparatus according to claim 1, wherein the automatic focusing control is performed using the plurality of AF evaluation values obtained in step 1. The imaging apparatus according to claim 1 or 2, wherein the search direction determination characterized in that it is performed by fine driving operation for determining the driving direction of the focus lens. The imaging apparatus according to any one of claims 1 to 3 determine the search direction, characterized in that it is performed during moving image shooting. The detection means, the specific as a region of the subject, the imaging apparatus according to any one of claims 1 to 4, characterized in that to detect a face area of a person. A control method of an imaging apparatus that performs automatic focusing control by driving a focus lens,
A detection step of detecting a region of a specific subject from the captured image;
A setting step of setting a focus detection region in a region including a region of a specific subject in the image based on a detection result in the detection step;
Generating an AF evaluation value based on a predetermined frequency band component included in the focus detection region of the image;
A first determination step of determining a search direction of the focus lens for searching for a focal point based on the AF evaluation value;
A second determination step of determining a search direction of the focus lens for searching for a focal point based on a change in the size of the area of the specific subject detected in the detection step;
The focus lens is moved to a plurality of positions based on the search direction determined in the first determination step or the second determination step, and the plurality of AF evaluation values obtained at the plurality of positions are used. A control step for performing the automatic focusing control ,
The control step moves the focus lens to a plurality of positions based on the search direction determined by the second determination step when the AF evaluation value is smaller than a predetermined value, and obtains the plurality of positions at the plurality of positions. Performing the automatic focusing control using the plurality of AF evaluation values obtained,
In the control step, when the AF evaluation value is equal to or greater than the predetermined value, the focus lens is moved to a plurality of positions based on the search direction determined in the first determination step, and obtained at the plurality of positions. A control method for an imaging apparatus, wherein the automatic focusing control is performed using the plurality of AF evaluation values obtained . In the computer of the imaging device that drives the focus lens and performs automatic focusing control,
A detection step of detecting a region of a specific subject from the captured image;
A setting step of setting a focus detection region in a region including a region of a specific subject in the image based on a detection result in the detection step;
Generating an AF evaluation value based on a predetermined frequency band component included in the focus detection region of the image;
A first determination step of determining a search direction of the focus lens for searching for a focal point based on the AF evaluation value;
A second determination step of determining a search direction of the focus lens for searching for a focal point based on a change in the size of the area of the specific subject detected in the detection step;
The focus lens is moved to a plurality of positions based on the search direction determined in the first determination step or the second determination step, and the plurality of AF evaluation values obtained at the plurality of positions are used. A control step for performing the automatic focusing control ,
The control step moves the focus lens to a plurality of positions based on the search direction determined by the second determination step when the AF evaluation value is smaller than a predetermined value, and obtains the plurality of positions at the plurality of positions. Performing the automatic focusing control using the plurality of AF evaluation values obtained,
In the control step, when the AF evaluation value is equal to or greater than the predetermined value, the focus lens is moved to a plurality of positions based on the search direction determined in the first determination step, and obtained at the plurality of positions. A program for executing a control method of an imaging apparatus that performs the automatic focusing control using a plurality of the AF evaluation values . In the computer of the imaging device that drives the focus lens and performs automatic focusing control,
A detection step of detecting a region of a specific subject from the captured image;
A setting step of setting a focus detection region in a region including a region of a specific subject in the image based on a detection result in the detection step;
Generating an AF evaluation value based on a predetermined frequency band component included in the focus detection region of the image;
A first determination step of determining a search direction of the focus lens for searching for a focal point based on the AF evaluation value;
A second determination step of determining a search direction of the focus lens for searching for a focal point based on a change in the size of the area of the specific subject detected in the detection step;
The focus lens is moved to a plurality of positions based on the search direction determined in the first determination step or the second determination step, and the plurality of AF evaluation values obtained at the plurality of positions are used. A control step for performing the automatic focusing control ,
The control step moves the focus lens to a plurality of positions based on the search direction determined by the second determination step when the AF evaluation value is smaller than a predetermined value, and obtains the plurality of positions at the plurality of positions. Performing the automatic focusing control using the plurality of AF evaluation values obtained,
In the control step, when the AF evaluation value is equal to or greater than the predetermined value, the focus lens is moved to a plurality of positions based on the search direction determined in the first determination step, and obtained at the plurality of positions. A computer-readable recording medium having recorded thereon a program for executing a control method of an imaging apparatus that performs the automatic focusing control using the plurality of AF evaluation values . The determination operation based on a change in the size of the area of the specific subject by the second determination unit is performed after the determination operation based on the AF evaluation value by the first determination unit. Item 6. The imaging device according to any one of Items 1 to 5 . The determination operation based on a change in the size of the specific subject area in the second determination step is performed after the determination operation based on the AF evaluation value in the first determination step. Item 7. A method for controlling an imaging apparatus according to Item 6 . The determination operation based on a change in the size of the specific subject area in the second determination step is performed after the determination operation based on the AF evaluation value in the first determination step. Item 8. The program according to item 7 . The determination operation based on a change in the size of the specific subject area in the second determination step is performed after the determination operation based on the AF evaluation value in the first determination step. Item 9. A computer-readable recording medium according to Item 8 .

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