JP5355252B2 - Imaging apparatus and control method thereof - Google Patents

Description

  The present invention relates to an imaging apparatus such as a video camera, and more particularly to an imaging apparatus capable of focus control by a contrast detection method and a phase difference detection method, and a control method thereof.

  As a focus control (autofocus: AF) system of an imaging apparatus, there is a contrast detection system (also referred to as a TV-AF system) that uses contrast information obtained from high-frequency components of an image generated by imaging. There is also a phase difference detection method that uses a phase difference between two subject images formed by a phase difference detection optical system. Further, there is a hybrid system that combines a contrast detection system and a phase difference detection system.

  In the phase difference detection method, since distance information to the subject can be obtained in principle, focus control can be performed in a short time, but because a phase difference detection optical system different from the photographing optical system is used. However, the accuracy of focus control is slightly low. On the other hand, in the contrast detection method, since distance information to the subject cannot be obtained in principle, focus control takes some time, but highly accurate focus control is possible.

  In the hybrid method, a focus vicinity position can be obtained at high speed by the phase difference detection method, and focus control can be performed to a highly accurate focus state by the contrast detection method, so that high-speed and high-precision focus control is possible. In addition, when the hybrid method is used, there is an advantage that even when photographing at an extremely close distance such as macro photographing that cannot be handled by the phase difference detection method, the contrast detection method can be used.

  Further, Patent Document 1 discloses an imaging apparatus that detects a specific subject such as a human face from an image and performs high-speed and high-precision focus control by a hybrid method using the specific subject as a focusing target.

JP 2005-012307 A

  However, in the imaging device disclosed in Patent Document 1, while the focus control is performed on the specific subject by the phase difference detection method (the focus lens is moved), the contrast detection method for the specific subject is used. Not evaluated. For this reason, when shifting from the focus control using the phase difference detection method to the focus control using the contrast detection method while tracking the specific subject, the contrast information of the specific subject must be acquired again. The time until the focus state is obtained becomes longer.

  The present invention provides an imaging apparatus capable of performing high-precision focus control on a specific subject at a higher speed by a hybrid method, and a control method therefor.

An image pickup apparatus according to one aspect of the present invention detects an image pickup unit that photoelectrically converts a subject image formed by a photographing optical system including a focus lens, and detects a specific subject in an image generated using the output of the image pickup unit. Subject detection means; phase difference detection means for detecting a phase difference between two subject images formed by the phase difference detection optical system; contrast information generation means for generating contrast information in a focus detection region in the image; Control means for performing focus control by moving the focus lens based on the contrast information generated by the contrast information generation means and the phase difference detected by the phase difference detection means, and the control means Continues focus control using the contrast information generated by the contrast information generating means During the focus control that is repeatedly performed, a specific subject is detected by the subject detection unit, and a current position of the focus lens and a focus position based on the phase difference detected by the phase difference detection unit When the difference is determined to be larger than the first value and large blur, the focus lens starts to move based on the phase difference between the two subject images corresponding to the specific subject, and the focus based on the phase difference During the control, the moving speed of the focus lens is decelerated and the contrast information in the focus detection area corresponding to the area where the specific subject is detected is generated while the phase difference is detected based on the phase difference detected by the phase difference detecting means. The phase difference detected by the phase difference detecting means after moving the focus lens to a focal position The contrast information generated during the movement of the focus lens to the in-focus position based on the contrast information generated after the focus lens is moved to the in-focus position based on the phase difference detected by the phase difference detection means The focus control is performed using information .
According to another aspect of the present invention, there is provided a control method for an image pickup apparatus including an image pickup unit that photoelectrically converts a subject image formed by a shooting optical system including a focus lens, the output of the image pickup unit A subject detection step for detecting a specific subject in an image generated using the phase difference detection step, a phase difference detection step for detecting a phase difference between two subject images formed by the phase difference detection optical system, and a focus detection region in the image Focusing by moving the focus lens based on the contrast information generating step for generating contrast information in the image, and the contrast information generated in the contrast information generating step and the phase difference detected in the phase difference detecting step. A control step for performing control, and in the control step, the contrast information During the focus control in which the used focus control is continuously repeated, the specific subject is detected, and the difference between the current position of the focus lens and the focus position based on the phase difference is the first When it is determined that the blur is larger than the value, the focus lens starts to move based on the phase difference between the two subject images corresponding to the specific subject, and the focus is controlled during the focus control based on the phase difference. The focus lens is moved to the in-focus position based on the phase difference while generating the contrast information in the focus detection area corresponding to the area where the specific subject is detected while reducing the moving speed of the lens, and The contrast information generated during the movement of the focus lens to the focus position, and the focus And performing focus control by using said contrast information generated after movement of the focus lens to the location.

  More specifically, for example, the control means performs first contrast focus control using contrast information of the first image region set regardless of detection of a specific subject in the image as contrast focus control, and specifies in the image. Second contrast focus control using the contrast information of the second image area corresponding to the detection position of the subject is performed. Further, as the phase difference focus control, a first phase difference focus control using a phase difference detected in a first detection region set irrespective of detection of a specific subject in an image in a detection field of view of the phase difference detection means; Then, the second phase difference focus control using the phase difference detected in the second detection region corresponding to the detection position of the specific subject in the image in the detection visual field is performed. The control means performs the second phase difference focus control in response to the detection of the specific subject in the image in the state in which the first contrast focus control is performed, and the second phase difference focus control is completed. Later, second contrast focus control is performed. The control means is characterized in that the acquisition of the contrast information of the second image region is started before the second phase difference focus control is finished.

  In the present invention, high-speed and high-precision focus control can be performed on a specific subject.

1 is a block diagram showing a configuration of a video camera that is Embodiment 1 of the present invention. FIG. 3 is a block diagram illustrating a configuration of a TV-AF evaluation unit in the video camera according to the first embodiment. The figure explaining the principle of TV-AF. The figure explaining the principle of external measurement phase difference AF. The figure explaining the calculation by external measurement phase difference AF. 3 is a time chart showing a flow of AF control in the video camera of Embodiment 1. 9 is a time chart showing the flow of AF control in a video camera that is Embodiment 2 of the present invention. The block diagram which shows the structure of the TV-AF evaluation part in the video camera which is Example 3 of this invention.

Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows the configuration of a video camera as an image pickup apparatus that is Embodiment 1 of the present invention. The video camera includes an imaging lens (imaging optical system) 101, an image sensor 102, an imaging AFE (AFE1) 103, a phase difference lens (phase difference detection optical system) 104, a phase difference sensor 105, and a phase difference AFE ( AFE2) 106. In addition, the video camera includes a TV-AF evaluation value calculation unit (contrast information generation unit) 107, a face detection processing unit (subject detection unit) 108, a phase difference frame setting unit 109, a phase difference calculation unit 110, and a lens. A position control unit (focus control means) 111. Further, the video camera includes an image processing unit 112 and a display / recording unit 113.

  The image sensor 102 is composed of a CCD sensor or a CMOS sensor, and photoelectrically converts a subject image formed by the photographing lens 101. The imaging AFE 103 amplifies the analog signal output from the imaging element 102 and converts it into a digital signal, and generates imaging data (hereinafter referred to as image data or captured image).

  The phase difference lens 104 is provided as an optical system different from the photographing lens 101. The phase difference sensor 105 photoelectrically converts two images (two subject images) of the same subject formed by the phase difference lens 104 by two light receiving elements (line sensors), and two image signals corresponding to the two images. Output. The phase difference AFE 106 amplifies the two image signals (analog signals) output from the phase difference sensor 105 and converts them into digital signals. The phase difference calculation unit 110 calculates a phase difference between the two image signals, that is, a phase difference between the two subject images, and further calculates a distance to the subject based on the phase difference. The phase difference sensor 105 and the phase difference calculation unit 110 constitute phase difference detection means.

  Since the phase difference lens 104 is provided as an optical system that is completely different from the photographing lens 101, the phase difference detection method in this embodiment is also referred to as an external measurement phase difference detection method. However, the present invention can be applied not only to the external measurement phase difference detection method but also to the case where the internal measurement phase difference detection method using the phase difference detection optical system using a part of the photographing lens 101 is used.

  The TV-AF evaluation value calculation unit 107 extracts a high-frequency component from the image data from the imaging AFE 103 and performs a predetermined process, thereby generating a TV-AF evaluation value that is contrast information of the image data. The TV-AF evaluation value is a value corresponding to the focus state of the subject image formed on the image sensor 102.

  The face detection processing unit 108 detects the face of a person as a specific subject from image data (captured image) from the imaging AFE 103 using an image processing technique such as pattern matching.

  When the face detection processing unit 108 detects a face, the TV-AF evaluation value calculation unit 107 is a TV-AF frame (focus detection region) that is an image region corresponding to the face detection position in the captured image. Is selected, and a TV-AF evaluation value is calculated (generated) within this TV-AF frame.

  The phase difference frame setting unit 109 detects the phase difference corresponding to the detected position of the face in the image within the detection visual field of the phase difference sensor 105 when the face is detected by the face detection processing unit 108. A phase difference frame that is an area is selected. Then, the phase difference sensor 105 and the phase difference calculation unit 110 detect a phase difference between two images of the specific subject within the phase difference frame.

  The lens position control unit 111 includes focus control of a phase difference detection method using information on the subject distance calculated by the phase difference calculation unit 110, and a TV-AF evaluation value calculated by the TV-AF evaluation value calculation unit 107. And focus control of a contrast detection method using. Specifically, the focus control is control of the position of a focus lens (not shown) included in the photographing lens 101. In the following description, the phase difference detection type focus control is referred to as phase difference AF (phase difference focus control), and the contrast detection type focus control is referred to as TV-AF (contrast focus control).

  The image processing unit 112 performs predetermined image processing on the image data from the imaging AFE 103 to generate an image signal (video signal) suitable for display and recording. The display / recording unit 113 displays the image signal generated by the image processing unit 112 on a monitor (not shown) or records it on a recording medium (not shown).

  Next, TV-AF performed in the present embodiment will be described.

  FIG. 2 shows the configuration of the TV-AF evaluation value calculation unit 107. In the present embodiment, as shown in the lower right of FIG. 2, as the TV-AF frame, the TV-AF frame at the center of the screen, the TV-AF frame on the left side of the screen, and the TV-AF frame on the right side of the screen (hereinafter referred to as the center). Any one of the frame, the left frame, and the right frame). The TV-AF evaluation value calculation unit 107 calculates a TV-AF evaluation value with the selected TV-AF frame, and outputs the calculated TV-AF evaluation value to the lens position control unit 111.

  Image data (also referred to as input video here) input to the TV-AF evaluation value calculation unit 107 passes through the TE band-pass filter 201 and the FE band-pass filter 211 and is converted into absolute values by the ABSs 202 and 212. The The absolute value signals output from the ABSs 202 and 212 are input to the TE line peak hold 203 and the FE line peak hold 213.

  Each line peak hold holds the value (absolute value) of the largest absolute value signal output from the ABS in one horizontal line of the input video. The vertical frame signal generator 231 controls the TE line peak hold 203 and the FE line peak hold 213 in accordance with the change in the vertical coordinate of the input video. As a result, the absolute values held by the TE line peak hold 203 and the FE line peak hold 213 are input to the TE integration calculation unit 204 and the FE integration calculation unit 214, respectively.

  The horizontal frame signal generator 221 corresponds to the absolute value signals output from the ABSs 201 and 202 while checking which of the three TV-AF frames the horizontal coordinate of the input image corresponds to. Input to the line peak hold of the TV-AF frame. When the calculation of the TV-AF evaluation value in one frame of the input video is completed, the TE integration value and the FE integration value are output from the TE integration calculation unit 204 and the FE integration calculation unit 214 for each TV-AF frame.

  The TE integration value and the FE integration value respectively show different values in the in-focus state, the in-focus state, and the large blur state. As shown in FIG. 3, the sum of the TE integration value and the FE integration value changes so as to show a peak in the in-focus state (in-focus position) with respect to the change in the position of the focus lens. The lens position control unit 111 moves (shifts) the focus lens so that the sum of the TE integrated value and the FE integrated value approaches the peak value, thereby obtaining a focused state by the TV-AF.

  When the face detection processing unit 108 does not detect a face, the TV-AF evaluation value calculation unit 107 selects a central frame (first image region) from the three TV-AF frames described above, and the central frame The TV-AF evaluation value is calculated. That is, the center frame is a TV-AF frame set regardless of the detection of a specific subject in the image. The TV-AF in this case is referred to as normal TV-AF (first contrast focus control) in the following description.

  On the other hand, when a face is detected by the face detection processing unit 108, the TV-AF evaluation value calculation unit 107 determines the TV-AF frame (center frame, left) including the face based on the detected position of the face. The TV-AF evaluation value is calculated by selecting the TV-AF frame corresponding to the detected face position from the frame and the right frame. The TV-AF in this case is referred to as face priority TV-AF (second contrast focus control) in the following description.

  Next, the phase difference AF performed in the present embodiment will be described.

  FIG. 4 shows the phase difference lens 104 and the phase difference sensor 105 shown in FIG. The phase difference lens 104 includes two lenses A and B arranged so that their optical axes are parallel to each other. The two lenses A and B form two images of the same subject OBJ on the phase difference sensor 105. The two image signals output from the phase difference sensor 105 have a phase difference corresponding to the subject distance D, and when these are superimposed, a signal as shown in FIG. 5 is obtained. In FIG. 5, the horizontal axis indicates the position of the light receiving element (pixel) in the phase difference sensor 105, and the vertical axis indicates the level of the output signal from the phase difference sensor 105.

  The phase difference calculation unit 110 calculates a phase difference d1 or d2 between the two image signals, and calculates a subject distance D by a triangulation method using the phase difference. Based on the subject distance D, the lens position control unit 111 calculates the position (drive amount) of the focus lens from which an in-focus state is obtained, and controls to move (shift) the focus lens to that position.

  When the face detection processing unit 108 does not detect a face, the phase difference frame setting unit 109 detects the phase difference between the two images in the entire detection field of the phase difference sensor 105. The phase difference AF in this case is referred to as normal phase difference AF (first phase difference focus control) in the following description.

  On the other hand, when the face is detected by the face detection processing unit 108, the phase difference frame corresponding to the detected position of the face (including the face) in the detection field of the phase difference sensor 105 is selected and the phase difference and The subject distance is calculated. Here, it is assumed that the center frame, the left frame, and the right frame can be selected as the phase difference frame, similarly to the TV-AF frame shown in FIG. For example, if the phase difference detected in the selected left frame is d1 in FIG. 5, the distance D to the face is calculated based on d1. The phase difference AF in this case is referred to as face priority phase difference AF (second phase difference focus control) in the following description.

  In this embodiment, hybrid AF is performed by combining normal TV-AF, face priority TV-AF, normal phase difference AF, and face priority phase difference AF.

Next, the flow of the hybrid AF in the present embodiment will be described using the time chart of FIG.
(Normal TV-AF: Time T0-T1)
In the time T0 when no face is detected, normal TV-AF is performed. As described above, in normal TV-AF, the TV-AF evaluation value is calculated in the center frame, and the phase difference (subject distance) is detected in the entire detection field.

It is assumed that the face is detected in the left frame by the face detection processing unit 108 at time T1. At this time, the phase difference frame is set to the left frame in accordance with the face detection position. Here, it is assumed that 3 m is detected as the distance to the face. At time T1, the focus lens is not moved (hereinafter also referred to as lens shift), and the TV-AF frame is changed from the center frame to the left frame.
(Face priority phase difference AF: Time T2-T4)
At time T2, the normal TV-AF shifts to face priority phase difference AF for detecting the phase difference in the left frame. At time T2, the face-priority phase difference AF is being performed, but the acquisition of the TV-AF evaluation value calculated in the left frame is also started, and large blur determination of the input video is performed. At this time, the focus lens position is the infinity position (∞), and the distance to the face is 3 m.

  At time T3, the focus lens at the infinity position is shifted at a high speed to a position that is focused to some extent with respect to the distance of 3 m to the face (error about 1 m). While the lens shift is performed at high speed, the TV-AF evaluation value calculated in the left frame cannot be used, but there is no problem because the lens shift is performed based on the subject distance.

  Thus, in this embodiment, the acquisition target of the TV-AF evaluation value is changed to the left frame where the face is detected before the start of face priority TV-AF.

When the lens shift to a position where the focus is achieved to some extent during time T3 is completed, the TV-AF evaluation value calculated in the left frame can be used at time T4, so that the lens shift speed is faster than time T3. Decelerated to a slow speed (medium speed).
(Face priority TV-AF: Time T5)
Since acquisition of the TV-AF evaluation value calculated in the left frame has already started at the start of time T5, face-priority TV-AF using the TV-AF evaluation value calculated in the left frame is immediately started. can do. Here, it is assumed that the distance to the face changes from 3 m to 4 m at time T5. In face-priority TV-AF, the focused state on the face is maintained at a lens shift speed slower than time T4 while tracking the moving face.

As described above, in this embodiment, the face corresponding to the detected position of the face from before the face priority phase difference AF ends (during the focus control by the face priority phase difference AF or before the focus control by the face priority TV-AF starts). The TV-AF evaluation value calculated in the frame is acquired. Accordingly, when the face priority phase difference AF is shifted to the face priority TV-AF, it is not necessary to newly acquire the TV-AF evaluation value of the face. Further, when the in-focus position can be acquired from the TV-AF evaluation value, the focus adjustment can be performed based on the acquisition result. Therefore, the face priority TV-AF, that is, the hybrid AF while tracking the face can be performed at a higher speed than when the face TV-AF evaluation value is obtained again after the face priority phase difference AF is completed. it can.
(Face priority TV-AF: Time T6)
At time T6, it is assumed that the face being tracked during face priority TV-AF disappears (cannot be detected) or the face to be tracked (main face) is changed by the user's selection operation or the like. Yes. At this time T6, the face priority TV-AF is held, but the acquisition target of the TV-AF evaluation value is changed to the center frame. The focus lens is also shifted to the infinity position at a low speed.

  Next, the flow of hybrid AF in the video camera that is Embodiment 2 of the present invention will be described with reference to the time chart of FIG. The configuration of the video camera of this embodiment is the same as that of the first embodiment.

In FIG. 7, the normal TV-AF at time T0-T1, the face priority phase difference AF at time T2-T4, and the face priority TV-AF at time T5 are the same as in the first embodiment. Of course, the TV-AF frame (left frame) corresponding to the face detection position from the time T2-T4 before the end of the face priority phase difference AF (during the operation of the face priority phase difference AF or before the start of the face priority TV-AF). The same applies to the point where the acquisition of the TV-AF evaluation value calculated in (1) is started.
(Face priority TV-AF: Time T6)
At time T6, it is assumed that the face tracked during face priority TV-AF disappears or the face to be tracked (main face) is changed by the user's selection operation or the like. At time T6, the process shifts to normal TV-AF, and the TV-AF evaluation value acquisition target is also changed to the center frame. Here, no lens shift is performed.
(Normal phase difference AF: Time T7-T8)
At time T7, the process proceeds to normal phase difference AF. Also, from time T7, acquisition of the TV-AF evaluation value calculated in the center frame is started, and large blurring determination of the input video is performed.

  At time T8 after the large blur determination, the focus lens is shifted to the infinity position at high speed. While the lens shift is performed at high speed, the TV-AF evaluation value calculated in the left frame cannot be used, but there is no problem because the lens shift is performed based on the subject distance.

  As described above, in this embodiment, when a face tracked during face priority TV-AF disappears, the process shifts to normal TV-AF. For this reason, normal hybrid AF can be continued (restarted) more smoothly than in the case of continuing face priority TV-AF as in the first embodiment.

  In this embodiment, when the face tracked during the face priority TV-AF disappears, the normal phase difference AF is performed through the normal TV-AF. Then, during the normal phase difference AF, the acquisition of the TV-AF evaluation value of the center frame is started. Thereby, after normal phase difference AF, normal TV-AF using the TV-AF evaluation value of the center frame can be started quickly.

  Next, a video camera that is Embodiment 3 of the present invention will be described. The configuration of the video camera of the present embodiment is basically the same as that of the first embodiment, but the TV-AF evaluation value calculation unit 107 calculates a TV-AF evaluation value differently.

  FIG. 8 shows the configuration of the TV-AF evaluation value calculation unit 107 in this embodiment. Here, a TV-AF evaluation value obtained by multiplying a TV-AF evaluation value calculated in three TV-AF frames (a center frame, a left frame, and a right frame) by a weighting coefficient (W_L, W_C, W_R) is used. Use.

  In normal TV-AF, the center-weighted TV-AF evaluation is performed by setting the value of the weighting coefficient W_C for the center frame larger than the weighting coefficients W_L and W_R for the other TV-AF frames. In the face priority TV-AF, the weighting coefficient for the TV-AF frame including the face is set larger than the weighting coefficients for the other TV-AF frames.

Next, the flow of the hybrid AF in the present embodiment will be described using the time chart of FIG. 6 used in the first embodiment.
(Normal TV-AF: Time T0-T1)
In the time T0 when no face is detected, normal TV-AF is performed. As described above, in normal TV-AF, the TV-AF evaluation value is calculated with the largest weight for the center frame. The phase difference (subject distance) is detected over the entire detection field.

It is assumed that the face is detected in the left frame by the face detection processing unit 108 at time T1. At this time, the phase difference frame is set to the left frame in accordance with the face detection position. Here, it is assumed that 3 m is detected as the distance to the face. At time T1, lens shift is not performed, and for the TV-AF evaluation value, the weight of the center frame is reduced and the weight of the left frame is increased.
(Face priority phase difference AF: Time T2-T4)
At time T2, the normal TV-AF shifts to face priority phase difference AF for detecting the phase difference in the left frame. At time T2, the face-priority phase difference AF is being performed, but the acquisition of the TV-AF evaluation value calculated in the left frame is also started, and large blur determination of the input video is performed. At this time, the focus lens position is the infinity position (∞), and the distance to the face is 3 m.

  At time T3, the focus lens at the infinity position is shifted at a high speed to a position that is focused to some extent with respect to the distance of 3 m to the face (error about 1 m). While the lens shift is performed at high speed, the TV-AF evaluation value calculated in the left frame cannot be used, but there is no problem because the lens shift is performed based on the subject distance.

  Thus, in this embodiment, the weight of the left frame in which the face is detected for the TV-AF evaluation value is increased before the start of face priority TV-AF. Then, the focus lens is shifted so that the face is focused on the face by the face priority TV-AF, and after time T4, the process shifts to the face priority TV-AF in which the TV-AF evaluation value in the left frame is weighted. Prepare for.

When the lens shift to a position where the focus is achieved to some extent during time T3 is completed, the TV-AF evaluation value calculated in the left frame can be used at time T4, so that the lens shift speed is faster than time T3. Decelerated to a slow speed (medium speed). Then, the lens shift is performed up to a position where focus is obtained by the phase difference AF with respect to the distance of 3 m to the face.
(Face priority TV-AF: Time T5)
Since the weighted left frame TV-AF evaluation value has already been acquired at the start of time T5, the face-priority TV-AF using the left frame TV-AF evaluation value is immediately started. Can do. Here, it is assumed that the distance to the face changes from 3 m to 4 m at time T5. In face-priority TV-AF, the focused state on the face is maintained at a lens shift speed slower than time T4 while tracking the moving face.

In this embodiment, in the face-priority TV-AF, the TV-AF evaluation value of the TV-AF frame in which no face is detected is also referred to although the weight is lower than that of the TV-AF frame in which the face is detected. For this reason, even when the position of the face frequently fluctuates in the image, the face priority TV-AF can be continued smoothly.
(Face priority TV-AF time T6)
At time T6, it is assumed that the face tracked during face priority TV-AF disappears or the face to be tracked (main face) is changed by the user's selection operation or the like. At this time T6, the face priority TV-AF is maintained, but the weight of the TV-AF evaluation value in the center frame is increased, and the weight of the TV-AF evaluation value in the left frame is decreased. The focus lens is also shifted to the infinity position at a low speed.

  As described above, in each of the embodiments described above, when a specific subject is detected in an image, phase difference focus control is performed on the specific subject, and contrast focus control is performed on the specific subject after the phase difference focus control is completed. I do. As a result, high-speed and high-precision focus control can be performed on a specific subject.

  In addition, the acquisition of the contrast information of the specific subject is started before the phase difference focus control for the specific subject is completed. For this reason, when the phase difference focus control for the specific subject is shifted to the contrast focus control for the specific subject, it is not necessary to acquire the contrast information again. Therefore, contrast focus control for a specific subject, that is, focus control by a hybrid method while tracking the specific subject can be performed at higher speed. Note that the contrast information of the specific subject may be acquired after the phase difference focus control is completed.

  An imaging apparatus capable of performing high-precision focus control on a specific subject at a higher speed by the hybrid method can be realized.

DESCRIPTION OF SYMBOLS 101 Shooting lens 102 Image pick-up element 104 Phase difference detection lens 105 Phase difference sensor 107 TV-AF evaluation value calculating part 108 Face detection process part 109 Phase difference frame setting part 110 Phase difference calculating part 111 Lens position control part

Claims (4)

An imaging means for photoelectrically converting a subject image formed by a photographing optical system including a focus lens ;
A subject detecting means for detecting a specific object in an image generated using the output of the image pickup means,
Phase difference detection means for detecting a phase difference between two subject images formed by the phase difference detection optical system;
Contrast information generating means for generating contrast information in a focus detection region in the image;
Control means for performing focus control by moving the focus lens based on the contrast information generated by the contrast information generation means and the phase difference detected by the phase difference detection means;
The control means is a case where a specific subject is detected by the subject detection means during focus control in which focus control using the contrast information generated by the contrast information generation means is continuously repeated. When the difference between the position of the focus lens and the in-focus position based on the phase difference detected by the phase difference detection unit is determined to be larger than the first value and large blur, the two corresponding to the specific subject The focus lens starts to move based on the phase difference of the subject image, decelerates the moving speed of the focus lens during focus control based on the phase difference , and the focus corresponding to the region where the specific subject is detected detected by the phase difference detecting means while generating the contrast information in the detection area The contrast information generated during the movement of the focus lens to the in-focus position based on the phase difference detected by the phase difference detection unit after the focus lens is moved to the in-focus position based on the phase difference; and An imaging apparatus , wherein focus control is performed using the contrast information generated after the focus lens is moved to a focus position based on a phase difference detected by the phase difference detection means . The control means moves the focus lens to a focus position based on the phase difference detected by the phase difference detection means, and further decelerates the moving speed of the focus lens, and the contrast information generation means performs the contrast The imaging apparatus according to claim 1, wherein information is acquired. The control means corresponds to the contrast information in the focus detection area corresponding to the area where the specific subject is detected and the area where the specific subject is detected when the specific object is detected by the subject detection means. 3. The imaging apparatus according to claim 1, wherein the contrast information in the focus detection area that is not used is weighted and used for focus control. A method for controlling an image pickup apparatus having an image pickup means for photoelectrically converting a subject image formed by a shooting optical system including a focus lens ,
A subject detection step of detecting a specific subject in an image generated using the output of the imaging means ;
A phase difference detection step for detecting a phase difference between two subject images formed by the phase difference detection optical system;
A contrast information generating step for generating contrast information in a focus detection region in the image;
Wherein on the basis of the said detected phase difference by the contrast information generated by the contrast information generating step and the phase difference detection step, by moving the focus lens and a control step of performing focus control,
In the control step, during the focus control in which the focus control using the contrast information is continuously repeated, the specific subject is detected, and the focus is based on the current position of the focus lens and the phase difference. When it is determined that the difference from the focal position is larger than the first value and is largely blurred, the focus lens starts to move based on the phase difference between the two subject images corresponding to the specific subject. During focus control based on the phase difference, the moving speed of the focus lens is decelerated and the contrast information in the focus detection area corresponding to the area where the specific subject is detected is generated to the in-focus position based on the phase difference. Generated during movement of the focus lens to the in-focus position after moving the focus lens The contrast information, and a control method of an imaging device and performs focus control using the said contrast information generated after movement of the focus lens to the focus position.