JP6257231B2 - IMAGING DEVICE AND CONTROL METHOD OF IMAGING DEVICE - Google Patents

Description

  The present invention relates to switching control of focus adjusting means in an imaging apparatus provided with a plurality of types of focus adjusting means.

  2. Description of the Related Art Conventionally, an imaging device such as a digital camera that can sequentially convert an optical image formed by a photographing optical system into an image signal using an imaging device or the like to generate, record, and reproduce image data such as a still image or a moving image Is generally put into practical use and widely used. This type of imaging apparatus usually includes an automatic focus adjustment (autofocus; AF) means for automatically performing focus adjustment.

  In recent years, in such a conventional imaging apparatus, a plurality of types of focus adjusting means, for example, a plurality of imaging pixels arranged two-dimensionally over the entire light receiving surface (imaging surface) of the imaging element are used. Imaging using a means for performing contrast detection type automatic focus adjustment (autofocus; AF) control and a plurality of focus detection pixels arranged in a partial area of the plurality of imaging pixels arranged on the imaging surface. Various proposals have been made for an image pickup apparatus provided with means for performing an automatic focus adjustment (autofocus; AF) control of a surface phase difference detection method, and it is gradually being put into practical use.

  For example, an imaging apparatus disclosed in Japanese Patent Laid-Open No. 2013-3501 is an imaging apparatus including an imaging element in which imaging pixels and focus detection pixels are two-dimensionally arranged on an imaging surface, and includes focus detection. A first focus adjustment unit that performs focus adjustment by a phase difference detection method based on an output signal of a pixel for imaging, a second focus adjustment unit that performs focus adjustment by a contrast method based on an output signal of an imaging pixel, and a main subject Recognizing image processing means, and switching between the first focus adjusting means and the second focus adjusting means based on the positional relationship between the main subject and the focus detection area. In this case, for example, when the main subject moves out of the focus detection area during the focus adjustment by the first focus adjustment means, the first focus adjustment means is switched to the second focus adjustment means, and the operation of the first focus adjustment means is performed. Is to stop.

  In addition, the imaging device disclosed in Japanese Patent Application Laid-Open No. 2008-134390 can perform focus detection at higher speed and higher accuracy when performing focus detection using both the phase difference detection method and the contrast detection method. That's it.

JP2013-3501A JP 2008-134390 A

  However, the imaging apparatus disclosed in the above Japanese Patent Application Laid-Open No. 2013-3501 performs switching between the first focus adjustment unit and the second focus adjustment unit based on the positional relationship between the main subject and the focus detection area. However, no other switching conditions are presented. Therefore, for example, when the focus adjusting means is switched based on the positional relationship between the main subject and the focus detection area, since the response is not taken into consideration, switching control that impairs high speed and high accuracy may be performed. There may be some problems.

  In addition, the imaging apparatus disclosed by the above-mentioned Japanese Patent Application Laid-Open No. 2008-134390 aims to increase the speed and accuracy when performing focus detection using both the phase difference detection method and the contrast detection method. However, this is not to select and control either one of the phase difference detection method and the contrast detection method. In addition, since the focus lens is driven at the time of focus detection by the phase difference detection method, there is a problem that time restriction occurs and speeding up of the focus detection operation is also restricted.

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide an image pickup apparatus including a plurality of types of focus adjusting means on a surrounding situation or an image pickup surface when shooting. Automatic switching control that selects an appropriate focus adjustment method according to various conditions and conditions, such as the status of the image of the object being imaged, and switches to the automatic focus adjustment means corresponding to the selected focus adjustment method It is providing the imaging device which can be performed to.

In order to achieve the above object, an imaging device of one embodiment of the present invention includes an imaging optical system including a lens that forms a subject image, and imaging pixels that are two-dimensionally arranged over the entire imaging surface. In addition, an imaging element in which a plurality of focus detection pixels are arranged in at least a part of the arrangement, a first focus adjustment unit that performs focus adjustment based on an output signal from the imaging pixel, and the focus detection A second focus adjustment unit that performs focus adjustment based on an output signal from the pixel; and, depending on a situation, selection of one of the first focus adjustment unit and the second focus adjustment unit is determined. and AF method selection determining means for, based on the determination result by the AF method selection determining means, anda control section and a switching means for switching between said first focusing means and the second focusing means , you to the control unit That the AF mode selection determining means is an area set for performing the automatic focus process at the time of receiving the instruction signal for starting the focusing operation by said second focusing means, and the lens is in-focus position If it is determined that the second focus adjustment unit is selected, the switching unit in the control unit determines that the AF method selection determination unit selects the second focus adjustment unit. , Switching to the second focus adjusting means .

In order to achieve the above object, a method for controlling an image pickup apparatus according to an aspect of the present invention includes a method for determining the information on the contrast value, the elapsed time, and the image pattern in the AF area at the time of final focusing by the in-focus vicinity determining unit. Based on at least one of the information, it is determined whether or not the current lens position is in the vicinity of the in-focus position, and the defocus amount acquired by the second focus adjustment unit by the phase difference reliability prior determination unit and the imaging optical The reliability of the focus adjustment result by the second focus adjustment unit is determined in advance based on at least one or both of the system specification data, and the first focus from the current lens position is determined by the AF time estimation unit. and processing time by adjusting means, respectively obtains current from the lens position and the processing time by the second focusing means, the control unit, the focus proximity determination hand Or above determination result of the phase difference reliability advance determining means, or to select the appropriate AF method in accordance with the processing time acquired by the AF time estimating means, the selection of the AF method, the above-mentioned focus proximity determination means Thus, when it is determined that the current lens position is in the vicinity of the in-focus position, or each determination result in the phase difference reliability prior determination unit has reliability of the focus adjustment result by the second focus adjustment unit. In the three cases, or when the processing time by the second focus adjusting means acquired by the AF time estimating means is a predetermined processing time by the first focus adjusting means. The AF method is selected as the second focus adjustment means when it is determined that any one of the two cases, and the other is the second focus adjustment means. Selecting the focusing means.

  According to the present invention, in an imaging apparatus including a plurality of types of focus adjustment means, according to various conditions and situations such as the surrounding situation when shooting and the situation of the subject image formed on the imaging surface. Thus, it is possible to provide an imaging apparatus that can automatically perform switching control for selecting an appropriate focus adjustment method and switching to an automatic focus adjustment unit corresponding to the selected focus adjustment method.

1 is a block configuration diagram showing a schematic configuration of an imaging apparatus (camera) according to a first embodiment of the present invention. Conceptual diagram schematically showing each operation of contrast AF processing and image plane phase difference AF processing Conceptual diagram showing the operations of the contrast AF process and the image plane phase difference AF process in time series when the AF process is started from the focused state Conceptual diagram showing time-series operations of contrast AF processing and image plane phase difference AF processing when AF processing is started from an out-of-focus state Conceptual diagram showing the operation of AF processing when the switching of the frame rate is not accompanied when the AF instruction signal is generated (when the imaging switching time Tsw = 0). The main flowchart which shows the effect | action of the imaging device (camera) of the 1st Embodiment of this invention. Flowchart of a subroutine of full time AF mode processing (S200) in the main flowchart of FIG. A flowchart of a subroutine of the single AF mode process (S300) in the flowchart of FIG. Flowchart of a subroutine for single AF mode processing in the operation of the imaging apparatus (camera) of the second embodiment of the present invention. The flowchart of the subroutine of the AF method selection determination process (S500) in the flowchart of FIG. FIG. 10 is a flowchart of a subroutine for in-focus vicinity determination processing (S600). Flowchart of subroutine of phase difference reliability pre-determination process (S700) in the flowchart of FIG. FIG. 10 is a flowchart of a subroutine of AF time estimation processing (S800). The flowchart of the subroutine of the image plane phase difference AF process (S506) in the flowchart of FIG.

  The present invention will be described below with reference to the illustrated embodiments. In each embodiment of the present invention described below, an optical image formed by, for example, a photographing optical system is sequentially converted into an image signal by using an imaging element, and image data such as a still image and a moving image is generated and recorded. An image pickup apparatus such as a digital camera (hereinafter simply referred to as a camera) that can be reproduced.

[First Embodiment]
First, a schematic configuration of the imaging apparatus (camera) according to the first embodiment of the present invention will be described below. FIG. 1 is a block diagram illustrating a schematic configuration of an imaging apparatus (camera) according to the present embodiment.

  As shown in FIG. 1, the imaging apparatus 1 of the present embodiment is mainly configured by a camera body 10 and a lens barrel 30. The camera 1 is a so-called interchangeable lens camera in which a lens barrel 30 is detachably attached to a camera body 10.

  In this embodiment, an interchangeable lens camera will be described as an example of an imaging apparatus (camera). However, an imaging apparatus (camera) to which the present invention can be applied is not limited to this form. For example, a lens-fixed camera in which the camera body 10 and the lens barrel 30 are integrally formed can be applied in exactly the same manner.

  The camera body 10 includes a signal processing control unit 11, an imaging unit 12, a flash memory 13, a face detection unit 14, a clock unit 15, an operation unit 16, an SDRAM 17, a display device 18, and a display driver 19. The touch panel 20, the touch panel driver 21, the angular velocity sensor 22, the acceleration sensor 23, a recording unit including a recording medium 24 and a memory interface 25, a body side communication unit 26, and the like.

  The signal processing control unit 11 has a function as a control unit that comprehensively controls the entire operation of the camera 1, and serves as a control unit that processes control signals for controlling each component unit including the lens barrel 30. It is a circuit unit that functions as a signal processing unit that receives a series of image signals (image data) acquired by the imaging element 12a and performs predetermined signal processing and the like.

  Inside the signal processing control unit 11, there are various circuit units such as an AF signal calculation unit 11b, an image processing unit 11c, an exposure control unit 11d, a distance measurement calculation unit 11e, an image movement amount detection unit 11f, and an operation control unit 11g. It is equipped.

  Among these, the AF signal calculation unit 11b is a circuit unit that performs signal processing related to focus adjustment processing such as contrast detection processing or phase difference detection processing based on image data output from the image sensor 12a.

  The image processing unit 11c is a processing circuit unit that performs various types of signal processing based on image data acquired by the image sensor 12a.

  The exposure control unit 11d is a circuit unit that performs arithmetic processing for exposure control based on image data output from the image sensor 12a.

  The distance measurement calculation unit 11e is a circuit unit that performs calculation processing for distance measurement processing based on image data output from the image sensor 12a.

  The image movement amount detection unit 11f detects the movement amount in the screen of a subject image (for example, a face image detected by the face detection unit 14 to be described later) specified in the screen based on the image data acquired by the imaging element 12a. This is a detection circuit unit.

  The operation control unit 11g is a control circuit unit that receives the instruction signal input from the operation unit 16 and performs various operation controls corresponding to the received instruction signal.

  The imaging unit 12 includes an imaging element 12a, a pixel addition reading unit 12b, a non-pixel addition reading unit 12c, and the like.

  The imaging element 12a includes an electronic component including a circuit unit that receives a subject image formed by a photographing optical system (such as the optical lens 33) included in the lens barrel 30 and performs photoelectric conversion processing to generate image data. It is. As the imaging device 12a, for example, a CCD image sensor using a circuit element such as a CCD (Charge Coupled Device) or a solid state image sensor such as a MOS image sensor using a MOS (Metal Oxide Semiconductor) or the like. A photoelectric conversion element or the like that is an imaging element is applied. The analog image signal output by the imaging element 12a is output to the signal processing control unit 11 and various signal processing is performed.

  In the imaging device 12a of the present embodiment, a plurality of imaging pixels that output signals for forming an image over the entire imaging surface (light receiving surface) are two-dimensionally arranged, and at least one of the arrangements. This is an image sensor in which a plurality of focus detection pixels that output a signal for performing focus detection are arranged in the unit.

  The pixel addition reading unit 12b is a circuit unit that reads out the output signal of the image sensor 12a by performing pixel addition processing. When the output signal of the image sensor 12a is read out via the pixel addition reading unit 12b, various processes when the camera 1 is in a shooting standby state, for example, a live view image display or an automatic exposure adjustment control process are performed. Or a case of performing a contrast detection type automatic focus adjustment (autofocus; AF) control process.

  The non-pixel addition reading unit 12c is a circuit unit that reads an output signal of the image sensor 12a without performing pixel addition processing. A case where the output signal of the image pickup device 12a is read out via the non-pixel addition reading unit 12c is, for example, a case where an automatic focus adjustment (autofocus; AF) control process using an image pickup surface phase difference detection method is performed.

  The flash memory 13 is a rewritable nonvolatile semiconductor memory that stores various control programs and various information data in advance. As the flash memory 13, for example, an EEPROM (Electrically Erasable Programmable Read-Only Memory) or the like is applied.

  The face detection unit 14 includes a human face or a specific type of animal or plant (eg, dog, cat, bird, flower, etc.) in an image to be displayed on the display device 18 based on image data output from the image sensor 12a. This is a subject image detection circuit unit for detecting whether there is an image corresponding to the subject. The face detection unit 14 may include not only a face image but also a part that performs color detection, pattern detection, and the like in addition to the face image detection. Note that the signal processing control unit 11 has a function of performing control and the like of continuing the focus adjustment by tracking the image pattern when the subject image detected by the face detection unit 14 moves within the shooting screen.

  The clock unit 15 is an internal clock of a computer called a so-called real-time clock (RTC). The clock unit 15 is used, for example, for giving date / time information such as a data file, or for measuring time or controlling time during control processing.

  The operation unit 16 is a variety of operation members such as a normal push button type, a slide type, or a dial type provided on an exterior portion of the camera body 10 of the camera 1. However, it refers to a component for operation including various general operation members such as a shutter release button. The instruction signal output from the operation unit 16 is output to the operation control unit 11g of the signal processing control unit 11, and various corresponding operation controls are executed in the operation control unit 11g.

  An SDRAM (Synchronous Dynamic Random Access Memory) 17 is a volatile semiconductor memory that temporarily records an image signal acquired by the image sensor 12a, various information data, and the like and is used for temporary work purposes.

  The display device 18 is a display device controlled by a display driver 19 that is controlled via the signal processing control unit 11. The display device 18 receives a display image data generated based on image data acquired by the image sensor 12a, for example, and displays a live view image, or is stationary based on image data recorded on the recording medium 24. This is a display unit that displays an image or a moving image and displays a menu display generated by reading various data prepared in advance in the recording medium 24 or the SDRAM 17 or the like.

  As the display device 18, for example, a display panel such as a liquid crystal display (LCD), a plasma display (PDP), an organic electro-luminescence display (OEL), a driving circuit thereof, and the like are provided. Consists of including.

  More specifically, when the operation mode of the camera 1 is set to the playback mode under the control of the display driver 19 via the signal processing control unit 11, the display device 18 displays an image based on image data that has been recorded. It functions as a display device that reproduces and displays (still images, moving images, etc.). On the other hand, when the operation mode of the camera 1 is set to the photographing mode, similarly, under the control of the display driver 19 via the signal processing control unit 11, processed image data is received through the image processing unit 11c and sequentially received. By continuing to display real-time images continuously, it functions as an electronic view finder (EVF) that can observe and confirm the shooting range.

  The display device 18 is, for example, provided on the back side of the camera body 10 and adopts a relatively large display panel (for example, a size of about 3 inches). Various types of forms such as a so-called electronic viewfinder configured by using a small display panel (for example, a size of about 0.5 type) that can be built in the body 10 are applied. Further, a plurality of display panels may be provided, and these may be used by switching appropriately according to the application.

  The display driver 19 is a control circuit unit that drives and controls the display device 18. The display driver 19 receives display image data (image signal) generated and acquired by the image sensor 12 a and generated through a predetermined process, and can be viewed as an image using the display panel of the display device 18. Performs control for display. The display driver 19 may be configured to perform image processing for generating image data for display.

  The touch panel 20 is an electronic component that is provided as an operation member of a different system from the operation unit 16. The touch panel 20 is disposed on the display panel of the display device 18, and a user (user) performs a touch operation on a predetermined region corresponding to an image being displayed on the display device 18, a region corresponding to various icon displays, or the like. By performing a slide operation or the like, various operation instruction signals are generated. The instruction input signal from the touch panel 20 is sent to the touch panel driver 21, and the operation input is determined.

  The touch panel driver 21 is a signal processing circuit that receives an instruction input signal from the touch panel 20 and determines the instruction content. For example, when an icon display or the like on the display image of the display device 18 is displayed, the user (user) performs a touch operation, a slide operation, or the like on the position on the touch panel 20 corresponding to the currently displayed icon display or the like. And determine their operation. The determination result by the touch panel driver 21 is transmitted to the signal processing control unit 11. Receiving this, the signal processing control unit 11 executes control processing corresponding to the determination result.

  The angular velocity sensor 22 is a sensor element that detects an angular velocity of a posture change (for example, shake) applied to the camera body 10. The acceleration sensor 23 is a sensor element that detects acceleration of posture change (for example, shake) applied to the camera body 10. The signal processing control unit 11 detects the posture of the camera body 10 based on the outputs of the angular velocity sensor 22 and the acceleration sensor 23. The detection result is obtained by, for example, driving a constituent unit including the image sensor 12a to perform predetermined shake correction control or the like, or driving control of an optical lens for shake correction via the lens control unit 31 of the lens barrel 30. It is used for performing etc. In addition to this, the posture detection result of the camera body 10 is also used, for example, to determine whether the camera body 10 is in the vertical position or the horizontal position, and such data is used as metadata of the recorded image data. Added.

  The recording unit is a constituent unit including a recording medium 24, a memory interface 25, and the like. The recording medium 24 is a device that records image data, various information, various programs, and the like. As the recording medium 24, for example, a card-type detachable or camera-embedded semiconductor memory medium or magnetic storage medium is applied. The memory interface 25 is a circuit unit including a signal processing circuit unit that controls input / output of image data, in addition to a control unit that drives and controls the recording medium 24.

  The memory interface 25 receives, for example, image data generated by the image pickup device 12a and subjected to predetermined processing through the image processing unit 11c, and converts it into image data for recording by performing signal compression processing or the like, for example. Processing is performed, or signal processing for restoring image data by reading image data recorded on the recording medium 24 and performing decompression processing or the like is performed. Note that the compression / decompression processing for image data is not limited to the form of processing in the memory interface 25. For example, a similar signal processing circuit unit is provided in the signal processing control unit 11 and is executed thereby. It is good also as a form.

  The body side communication unit 26 is a communication signal processing circuit unit provided for exchanging control signals, information signals, and the like between the camera body 10 and the lens barrel 30. When the lens barrel 30 is attached to the camera body 10, both are configured to be electrically connected via the interface 41.

  Here, the interface 41 is a member such as an electrical contact provided in both the camera body 10 and the lens barrel 30. The body side communication unit 26 is electrically connected to the body side interface 41 inside the camera body 10. A lens control unit 31 described later is electrically connected to the lens-side interface 41.

  Therefore, by connecting the camera body 10 and the lens barrel 30 via the interface 41, the signal processing control unit 11 on the camera body 10 side and the lens control unit 31 on the lens barrel 30 side are electrically connected. The In this state, the two cooperate to control the camera body 10 and the lens barrel 30, respectively.

  Next, the lens barrel 30 is mainly configured by a lens control unit 31, a lens driver 32, an optical lens 33 that is a photographing optical system, a diaphragm device 34, and the like.

  The lens control unit 31 is a control circuit unit that controls the operation of each component unit on the lens barrel 30 side under the control of the signal processing control unit 11 on the camera body 10 side or in cooperation therewith. The lens control unit 31 can be omitted. In that case, what is necessary is just to comprise so that the signal processing control part 11 by the side of the camera body 10 may perform all the control by the side of the lens-barrel 30.

  The optical lens 33 is a photographing optical system that forms an optical image of a subject by transmitting light from an object (subject) to be photographed. Although not shown in detail in the drawings, the optical lens 33 as the photographing optical system includes a plurality of holding frame members that hold the optical lenses and the plurality of holding frame members individually in the optical axis direction. In addition to the drive member that moves forward and backward, the zoom drive mechanism unit for zooming, the focus drive mechanism unit for focusing, and the like are configured units. Although not explicitly shown in this figure, there are sensors that detect the position of each lens and optical system, and this makes it possible to focus anywhere between the closest position and the infinity position or beyond the area. It is possible to determine whether a lens is arranged.

  The aperture device 34 includes an aperture mechanism for adjusting the amount of light beam transmitted through the photographing optical system, a drive source (actuator) for driving the aperture mechanism, a drive mechanism for transmitting the drive force, and the like. It is a structural unit including a drive circuit (driver) to be controlled.

  In addition to the components described above, the camera body 10 and the lens barrel 30 are configured to include other various structural units. Since the configuration is not directly related to the present invention, the detailed description and illustration are omitted because the configuration is the same as that of a conventional general camera.

  For example, illustration and description of a shutter mechanism for opening and closing the optical path of the photographing optical system and adjusting the amount of light beam transmitted through the photographing optical system during photographing operation are omitted, but the camera 1 of the present embodiment. Also has a normal shutter mechanism similar to a conventional camera. In this case, the shutter mechanism may be a focal plane shutter disposed on the camera body 10 side or a lens shutter disposed on the lens barrel 30 side. Further, instead of or in addition to a mechanical shutter mechanism, an element shutter function that functions as a shutter mechanism by electrically controlling the image sensor 12a may be provided. When the shutter mechanism is disposed on the camera body 10 side (including the element shutter), the shutter mechanism is mainly controlled by the control unit on the body side. When the shutter mechanism is disposed on the lens barrel 30 side, the shutter mechanism is controlled via the lens control unit 31 mainly under the control of the body side control unit.

  Among the actions when shooting is performed using the camera 1 of the present embodiment configured as described above, the action mainly related to the automatic focus adjustment (autofocus; AF) control processing (hereinafter simply referred to as AF control processing). This will be described in detail below.

  The camera 1 according to the present embodiment detects the in-focus state based on output signals from a plurality of imaging pixels arranged two-dimensionally over the entire imaging surface (light receiving surface) of the imaging element 12a. Based on output signals from a first focus adjusting unit that performs AF control processing of a contrast detection method for performing focus adjustment and a plurality of focus detection pixels arranged in a partial region of the imaging pixel. And a second focus adjusting unit that performs AF control processing of an imaging surface phase difference detection method that performs detection and performs focus adjustment.

  In any case, the AF control processing method receives the output signal from the image sensor 12a under the control of the signal processing control unit 11, and detects the in-focus position by the AF signal calculation unit 11b, the image processing unit 11c, and the like. The lens driver 32 is driven and controlled via the lens control unit 31 based on the detection result, and the optical lens 33 is moved to a predetermined in-focus position.

  In this case, the contrast detection AF control processing (hereinafter abbreviated as contrast AF processing) is performed based on the output signal (image signal) of the image sensor 12a output via the pixel addition reading unit 12b. Is detected. The contrast AF process is performed when the contrast (brightness / darkness difference) of the subject image formed on the imaging surface of the image sensor 12a is maximized (that is, the subject image formed on the imaging surface is in focus). This is a process for detecting the position of the optical lens 33 on the optical axis. Therefore, during the execution of the contrast AF process, the lens group (focus lens group) related to the focus adjustment operation (the lens holding frame for holding) of the optical lens 33 that is the photographing optical system is in the direction along the optical axis. The lens drive control is always performed.

  On the other hand, an AF control process (hereinafter abbreviated as an image plane phase difference AF process) of the imaging plane phase difference detection method is performed on an output signal (image signal) of the imaging element 12a output via the non-pixel addition reading unit 12c. Based on this, the focus position is detected. In the image plane phase difference AF process, the distance between a pair of images formed on the focus detection pixels of the image sensor 12a is detected, and the direction of the in-focus position is determined based on the currently set lens position. This is a process of determining the amount of shift in the in-focus state (hereinafter referred to as defocus amount) and moving the optical lens 33 to the in-focus position.

  In the signal processing control unit 11 of the camera 1, control processing (contrast AF processing, image processing) according to the above-described two types of focus adjustment methods is performed according to the surrounding situation and the situation of the subject image formed on the imaging surface. Control to automatically switch (surface phase difference AF processing) is performed. In this case, the signal processing control unit 11 functions as a switching unit that performs switching control of a plurality of focus adjusting units depending on the situation.

  As described above, in the image plane phase difference AF process, the in-focus state is detected using output signals from a plurality of focus detection pixels arranged in a partial area of the imaging plane. In the region where the focus detection pixels do not exist, the in-focus state cannot be detected, and there is a restriction that the region in which the in-focus state can be detected is limited.

  On the other hand, in the contrast AF process, the in-focus state is detected using a plurality of imaging pixels arranged two-dimensionally over the entire imaging surface. Therefore, it is more advantageous than the image plane phase difference AF process in that the in-focus state can be detected in any region within the imaging plane.

  On the other hand, in contrast AF processing, lens driving is always accompanied when detecting the in-focus state, whereas in image plane phase difference AF processing, focusing is performed from an output signal from a focus detection pixel without lens driving. Since the position direction and the defocus amount can be detected, there is an advantage that the focus adjustment operation can be speeded up as compared with the contrast AF process when the optical lens 33 is moved to the in-focus position.

  For example, FIG. 2 is a conceptual diagram schematically showing operations of contrast AF processing and image plane phase difference AF processing. 2A shows the operation of contrast AF, and FIGS. 2B and 2C show the operation of image plane phase difference AF processing. 2B shows an operation pattern when the defocus amount is small in the image plane phase difference AF process, and FIG. 2C shows a large defocus amount in the image plane phase difference AF process. The operation pattern in a certain case is shown.

  In FIG. 2, a focus adjustable range by the optical lens 33 is a range between a close range side end position P and an infinite position ∞. Further, the current lens position is indicated by a symbol P, and a focusing position that is a lens position to be moved is indicated by a symbol F. As shown in the figure, it is assumed that the current lens position P and the in-focus position F do not match.

  When contrast AF processing is performed to detect the in-focus position F in this situation, the optical lens 33 is driven and controlled, and the position where the contrast is maximized is detected while moving the lens 33 along the optical axis. . The example shown in FIG. 2A is an example of the case where it takes the longest time to detect the in-focus position F when performing contrast AF processing. A typical scene is when the subject is dark and has low contrast. For example, the lens is driven from the current lens position P to the closest end position Q. The lens is driven to infinity position ∞ after going to position Q, and the lens is driven toward infinity position ∞. Here, the contrast is clear, and after passing the in-focus position F, a so-called hill-climbing AF operation is performed. Is called.

  Next, when the image plane phase difference AF process is performed to detect the in-focus position F under the same situation and the defocus amount is small, the output signal from the focus detection pixel is Since the direction of the in-focus position and the amount of defocus can be detected based on this, the lens is driven from the current lens position P toward the in-focus position F as shown in FIG. In the image plane phase difference AF, since the degree of deviation of a plurality of images is observed, if the image is clear and the deviation is within the detection range, quick control without any hesitation is possible. As described above, in the imaging plane phase difference AF, it can be determined fairly accurately whether or not rapid processing can be performed.

  In addition, even when image plane phase difference AF processing is performed, if the defocus amount is large, there are cases where there is no contrast or darkness, but this is a problem peculiar to image plane phase difference AF. In some cases, the phase difference is too large to fall within the detectable range of the imaging surface. Even if the contrast is clear, in the case of the image plane phase difference AF that detects and adjusts the degree of deviation of a plurality of images, this may occur because there is a limit to the sensor size for viewing the deviation. At this time, the direction of the in-focus position and the defocus amount cannot be detected depending on the output signal from the focus detection pixel, and thus an operation pattern as shown in FIG. 2C is performed. In other words, in this case, even in the image plane phase difference AF process, the principle of detection failure may be different, and as in the contrast AF process, from the current lens position P toward the closest end position Q. The lens is driven, and the lens is driven toward the infinite position ∞ by turning back at the closest end position Q. At this time, for example, when the optical lens 33 comes to the position indicated by reference numeral P1 in FIG. 2C, the direction of the in-focus position and the defocus amount are detected by the output signal from the focus detection pixel. Then, the lens drive is temporarily stopped at this position, and then the lens drive is performed toward the detected focus position F. The example shown in FIG. 2C is an example in which the defocus amount is large and the direction of the focus position and the defocus amount cannot be detected by the output signal from the focus detection pixel. Specifically, for example, when the subject image to be focused is out of the area where the focus detection pixels are located on the imaging surface, in this case, in this case, the lens position (protruding distance to the nearest or infinity) ) May take longer than contrast AF. There are cases where which AF is advantageous depends on the speed at which the lens is stopped or moved, the time lag for switching the readout of AF pixels and display pixels, and the like. The following explanation touches what time lag occurs in each control state of the camera, the speed difference that occurs in lens driving, etc., but depending on these, the speed applied to AF depends and the contrast is clear, It depends on the relationship between the actual focus position and the current lens position.

  In the situation where the current lens position P and the in-focus position F do not match due to the integration of such conditions, the contrast AF processing is performed faster than the image plane phase difference AF processing. It can be said that the position detection and the lens movement to the in-focus position can be executed.

  In general, it is desired that a focus adjustment operation in an image pickup apparatus (camera) operates at high speed and accurately. On the other hand, the optimum focus adjustment method varies depending on the surrounding conditions when shooting, the situation of the subject image formed on the imaging surface, and the like. As described above, in the image plane phase difference AF, there is a problem that the detection range is limited depending on the contrast, relative and absolute lens position, and when the lens is driven, AF pixel readout and display pixel readout are performed. However, since the speed of moving the lens tends to be slow, the contrast AF can be performed only by reading out the display pixels, so that the lens can be moved quickly. However, this difference is small for heavy lenses (or actuators) that are originally slow. Taking these factors into account, select an advantageous method. The lens position considers the difference from the focusing position, or the distance to the close end and the infinity end.

  For example, when the imaging optical system of the camera is already in focus, that is, when the lens position of the focus lens that is a lens related to focus adjustment in the imaging optical system is already in the in-focus position, the image plane phase difference AF Processing is advantageous, and faster AF control processing can be executed. A specific example in this case will be described with reference to FIG.

  FIG. 3 is a conceptual diagram showing the operations of the contrast AF process and the image plane phase difference AF process in time series when the AF process is started from the focused state. 3A and 3B show the operation of the contrast AF process, and FIGS. 3C and 3D show the operation of the image plane phase difference AF process. 3A and 3C show the vertical synchronization signal VD, and FIGS. 3B and 3D show changes in the exposure amount.

  First, when normal live view image display is performed, the reading frame rate of the pixel data of the image sensor is, for example, 60 fps. It is assumed that during the live view image display operation, an AF instruction signal is generated by a first (1st.) Release operation at the time indicated by reference symbol R in the figure, and the AF operation starts. In this case, first, control processing for switching the reading frame rate to 120 fps is performed in order to perform AF control processing at high speed. Along with this switching process, a blank period B for one frame is generated to adjust the data reading timing. In this blank period B, pixel data for image display is not read. Here, the period from the generation time R of the AF instruction signal to the start of driving at 120 fps including the blank period is referred to as an imaging switching period (Tsw). When the frame rate is switched to the high speed side, the exposure amount decreases (see FIGS. 3B and 3D).

  Thus, after the frame rate is switched, in the contrast AF process, the pixel data reading control and the lens driving control of the predetermined area of the imaging pixels of the imaging device are performed, and the lens position in the in-focus state is obtained. (Focus position) is detected. In the example shown in FIG. 3B, it is assumed that the AF processing is completed in a period of approximately three frames.

  On the other hand, after the frame rate is similarly switched, in the image plane phase difference AF processing, reading control of pixel data of the focus detection pixels of the image sensor is performed without the lens driving control, and the in-focus state. The lens position (in-focus position) is detected. In the example shown in FIG. 3D, the AF process is completed in a period of approximately one frame.

  As described above, when the AF process is started from the in-focus state, the image plane phase difference AF process produces the AF process result faster than the contrast AF process by the time indicated by reference numeral T1 in FIG. Can be obtained.

  On the other hand, for example, when the photographing optical system of the camera is in an out-of-focus state, that is, when the lens position of the focus lens that is a lens related to focus adjustment in the photographing optical system is out of the in-focus position. The contrast AF process is more advantageous than the image plane phase difference AF process. A specific example in this case will be described with reference to FIG.

  FIG. 4 is a conceptual diagram showing the operations of the contrast AF process and the image plane phase difference AF process in time series when the AF process is started from the out-of-focus state. 4A and 4B show the operation of the contrast AF process, and FIGS. 4C and 4D show the operation of the image plane phase difference AF process. 4A and 4C show the vertical synchronization signal VD, and FIGS. 4B and 4D show changes in the exposure amount.

  Similar to the example shown in FIG. 3 described above, a control process is performed in which the reading frame rate when normal live view image display is performed is set to 60 fps, for example, and the reading frame rate is switched to 120 fps when the AF operation starts. Shall be. The imaging switching time (Tsw) is also generated along with this switching process.

  When the contrast AF processing is performed after the frame rate is switched from 60 fps to 120 fps on the high speed side, the lens position (in-focus position) in the in-focus state is detected in this example as well as in the above example. It is assumed that a period of approximately 3 frames is required until the operation is performed.

  On the other hand, when the image plane phase difference AF processing is performed after the frame rate is switched in the same manner, first, the lens that is in focus is controlled by reading the pixel data of the focus detection pixels of the image sensor. After the position (in-focus position) is detected, lens drive control toward that position is performed. In the example shown in FIG. 3D, the detection process is completed in a period of approximately one frame, but subsequent lens drive control is added.

  As described above, when the AF process is started from the out-of-focus state, the contrast AF process is faster than the image plane phase difference AF process by the time indicated by the symbol T2 in FIG. 4B. Can be obtained.

  When performing normal live view image display, if the surrounding environment is sufficiently bright, the image sensor may always be driven at a high speed (for example, a reading frame rate of 120 fps). In this case, the frame rate switching control at the time when the AF instruction signal is generated becomes unnecessary, and therefore the imaging switching time Tsw = 0, which contributes to shortening of the AF processing time. FIG. 5 shows an example of such a case.

  The operation of the camera 1 that is the imaging apparatus of the present embodiment configured as described above will be described below. FIG. 6 is a main flowchart showing the operation of the imaging apparatus (camera) of this embodiment. FIG. 7 is a flowchart of the subroutine of the full-time AF mode process (S200) in the main flowchart of FIG. FIG. 8 is a flowchart of a subroutine of the single AF mode process (S300) in the main flowchart of FIG.

  First, when the power switch of the camera 1 is turned on by a user (user), the camera 1 is activated and becomes usable. Here, by the power-on operation, the signal processing control unit 11 of the camera 1 performs a series of activation processes including a predetermined initialization process, but the activation process itself is not directly related to the gist of the present invention. Since it is a part, detailed description thereof is omitted.

  When the camera 1 is activated, first, in step S101 in FIG. 6, the signal processing control unit 11 checks whether or not the currently set operation mode is a shooting mode in which a shooting operation can be performed. If it is confirmed that the shooting mode is set, the process proceeds to step S102. If it is confirmed that an operation mode other than the shooting mode is set, processing corresponding to the other operation mode is executed. Here, the other operation modes are, for example, a reproduction mode and a communication mode. Since the processing in these operation modes is not directly related to the gist of the present invention, detailed description thereof is omitted.

  In step S <b> 102, the signal processing control unit 11 controls the exposure control unit 11 d to execute an automatic exposure adjustment (AE) control process based on image data output from the imaging unit 12. The automatic exposure adjustment (AE) control process itself executed here is the same control process as that performed in an image pickup apparatus (camera) of a conventional general form, and detailed description thereof is omitted. Thereafter, the process proceeds to step S103.

  In step S <b> 103, the signal processing control unit 11 starts imaging processing such as image signal acquisition processing in order to drive and control the imaging unit 12 to generate image data. The imaging process itself performed here is the same as the conventional general process. Thereafter, the process proceeds to step S104.

  In step S104, the signal processing control unit 11 controls the image processing unit 11c to execute predetermined image processing based on the image data acquired in the processing in step S104. This image processing itself is the same as conventional general processing. Thereafter, the process proceeds to step S104. Thereafter, the process proceeds to step S105.

  In step S105, the signal processing control unit 11 controls the display device 18 via the display driver 19 to display a live view image based on the display image data processed in the process of step S105. Execute display processing. Thereafter, the process proceeds to step S106.

  In step S106, the signal processing control unit 11 controls the face detection unit 14 and the like to execute a general moving object determination process. Thereafter, the process proceeds to step S107.

  In step S107, the signal processing control unit 11 checks whether or not the currently set shooting mode is the moving image shooting mode. If it is confirmed that the moving image shooting mode is set, the process proceeds to step S108. If it is confirmed that the moving image shooting mode is not set, that is, the still image shooting mode is set, the process proceeds to step S109.

  In step S108, the signal processing control unit 11 performs a predetermined moving image recording process. This moving image recording process is also assumed to be the same as that performed in a conventional general imaging device (camera), and detailed description thereof is omitted. Thereafter, the process proceeds to step S109.

  In step S109, the signal processing control unit 11 checks whether or not the currently set automatic focus adjustment control process (AF control process) is in the full-time AF mode. Here, the full-time AF mode is an operation mode in which the AF control process is continuously executed without waiting for an operation instruction from the user (user) when the camera 1 is activated and is in a shooting standby state. is there. As a form of AF control processing that can be set in the camera 1, in addition to the full-time AF mode, for example, AF control processing is performed at the timing when a user (user) operates an operation member such as a shutter release button or an AF button. There is a first (1st.) Release AF mode for starting the operation.

  If it is confirmed in step S109 that the current AF control processing mode is the full-time AF mode, the process proceeds to step S200 (refer to the subroutine of FIG. 7 for details). If it is confirmed that the setting is other than the full-time AF mode, the process proceeds to step S110.

  In the present embodiment, the first release AF mode is used as a setting other than the full-time AF mode. Here, other forms of AF control processing are also conceivable, but in the present embodiment, description thereof is omitted.

  There are a plurality of operation modes in the first release AF mode. Specifically, for example, a single AF mode and a continuous AF mode are used. Here, in the single AF mode, in response to one fast release operation (for example, half-pressing operation of the shutter-release button or pressing operation of the AF button) by the user (user), the AF control processing is executed only once. A mode in which the AF control processing result is maintained in a fixed state while the first release operation is maintained is a so-called AF lock state. In the continuous AF mode, an AF control process is started in response to one fast release operation by the user (user), and, for example, a posture change occurs while the first release operation is maintained. This is a form in which AF control processing is repeatedly executed whenever a change occurs in the state of the subject image on the imaging surface.

  As described above, when it is confirmed in the process of step S109 that the full-time AF mode is set and the process proceeds to step S200, the signal processing control unit 11 performs the full-time AF mode in step S200. Execute the process. Details of the full-time AF mode processing are shown in the subroutine of FIG.

  In step S201 of FIG. 7, the signal processing control unit 11 checks whether or not an area (region) for performing the image plane phase difference AF processing is set. Here, in the image plane phase difference AF possible area setting process, a user (user) is selected from among a plurality of image plane phase difference AF possible areas arranged in the imaging plane, that is, a plurality of areas where focus detection pixels are arranged. ) Is set by selecting a desired area by performing an operation, or by automatically selecting and controlling a region corresponding to an optical image formed on the imaging surface, a high contrast region, or the like. Area. In this case, if it is confirmed that an area (area) is set that enables the image plane phase difference AF process, the process proceeds to step S202. If the same setting is not confirmed, the process proceeds to step S203.

  In step S202, the signal processing control unit 11 acquires an exposure value on the imaging surface via the exposure control unit 11d, and whether or not the acquired exposure value is EV5 or more, that is, whether or not the environment is sufficiently bright. Confirm that. If it is confirmed that the EV is 5 or more, the process proceeds to step S204. If it is less than EV5, the process proceeds to step S203.

  In step S203, the signal processing control unit 11 performs a predetermined contrast AF process. The contrast AF process itself is the same as the conventional general process, and detailed description thereof is omitted. Thereafter, the process proceeds to step S205.

  On the other hand, in step S204, the signal processing control unit 11 executes predetermined image plane phase difference AF processing. This image plane phase difference AF process itself is the same as the conventional general process, and detailed description thereof is omitted. In this image plane phase difference AF process, information about the defocus amount described later is acquired. Thereafter, the process proceeds to step S205.

  In step S205, the signal processing control unit 11 checks whether or not the image in the imaging surface is in focus. If it is confirmed that the in-focus state is obtained, the process proceeds to step S206. If it is confirmed that the in-focus state is not obtained, the series of processes is terminated, the process returns to the original process sequence of FIG. 6 (return), and the process proceeds to step S110 of FIG.

  On the other hand, in step S206, the signal processing control unit 11 performs a process of recording the image pattern of the focus area (focus area) as information data. This information data is temporarily stored in, for example, the SDRAM 17 or a temporary memory unit (not shown) provided in the signal processing control unit 11 in order to store temporary information data.

  In step S207, the signal processing control unit 11 executes a process of acquiring a contrast value in the in-focus area (area). Thereafter, the process proceeds to step S208.

  In step S208, the signal processing control unit 11 refers to the clock unit 15 and acquires time information data at the time of focusing. These various information data acquired are temporarily stored in, for example, the SDRAM 17 or the temporary memory unit (not shown) of the signal processing control unit 11. Thereafter, the series of processes is terminated, the process returns to the original process sequence of FIG. 6 (return), and the process proceeds to step S110 of FIG.

  Returning to FIG. 6, in step S <b> 110, the signal processing control unit 11 changes the attitude of the camera 1, that is, in the direction in which the optical axis of the optical lens 33 faces, based on outputs from the angular velocity sensor 22, the acceleration sensor 23, and the like. Check if the posture has changed. If a change in posture is confirmed, the process proceeds to step S111. If no posture change is confirmed, the process proceeds to step S112.

  In step S111, the signal processing control unit 11 records posture change information based on the outputs from the angular velocity sensor 22, the acceleration sensor 23, and the like acquired in the processing in step S110, for example, the SDRAM 17 or the signal processing control unit 11 described above. Is temporarily stored in a temporary memory unit (not shown). Thereafter, the process proceeds to step S112.

  In step S112, the signal processing control unit 11 checks whether or not an AF instruction signal due to a first release operation or the like has occurred among instruction signals from the operation unit 16 via the operation control unit 11g. If the AF instruction signal is confirmed, the process proceeds to step S113. If the AF instruction signal is not confirmed, the process proceeds to step S114.

  In step S113, the signal processing control unit 11 confirms whether or not the currently set operation mode in the first release AF mode is the single AF mode. If it is confirmed that the single AF mode is set, the process proceeds to step S300 (refer to the subroutine of FIG. 8 for details). If it is set to other than the single AF mode, the process proceeds to step S114. Here, other AF operation modes are also conceivable, but in the present embodiment, their description is omitted.

  As described above, when the single AF mode is confirmed in the process of step S113 and the process proceeds to step S300, in step S300, the signal processing control unit 11 executes the single AF mode process. Details of the single AF mode processing are shown in the subroutine of FIG. Note that the subroutine of the single AF mode process is substantially the same as the subroutine of the full-time AF mode process of FIG. Therefore, the flow of the action is based on FIG. 7 and will be briefly described below.

  Step S301 in FIG. 8 is substantially the same as the process in step S201 in FIG. That is, in step S301, the signal processing control unit 11 checks whether or not an image plane phase difference AF processable area (area) is set. If the setting of the image plane phase difference AF processable area is confirmed, the process proceeds to step S302. If the same setting is not confirmed, the process proceeds to step S303.

  In step S <b> 302, the signal processing control unit 11 confirms whether or not the elapsed time since the last focusing is within a predetermined time. Here, the time of final focusing refers to the time when the AF control process that has been executed in one of steps S203 and S204 in FIG. 7 or one of steps S303 and S304 in FIG. is there.

  If it is confirmed in the process of step S302 that the elapsed time from the final focusing time is within a predetermined time, the process proceeds to step S304. On the other hand, if the elapsed time from the final focusing time exceeds the predetermined time, the process proceeds to step S303.

  Step S303 is the same as the process of step S203 of FIG. That is, in step S303, the signal processing control unit 11 executes a predetermined contrast AF process. Thereafter, the process proceeds to step S305.

  On the other hand, step S304 is the same as the process of step S204 of FIG. That is, in step S304, the signal processing control unit 11 executes predetermined image plane phase difference AF processing. Thereafter, the process proceeds to step S305.

  Henceforth, each process of step S305-step S308 is the same as each process of step S205-step S308 of FIG. As in the sequence of FIG. 7, the acquired various information data is temporarily stored in, for example, the SDRAM 17 or a temporary memory unit (not shown) of the signal processing control unit 11. Thereafter, the series of processes is terminated, the process returns to the original process sequence of FIG. 6 (return), and the process proceeds to step S114 of FIG.

  Returning to FIG. 6, in step S114, the signal processing control unit 11 determines whether or not a shooting instruction signal is generated by a second (2nd.) Release operation or the like among the instruction signals from the operation unit 16 via the operation control unit 11g. Confirm that. If the shooting instruction signal is confirmed here, the process proceeds to step S115. If the shooting instruction signal is not confirmed, the process returns to step S101.

  In step S115, the signal processing control unit 11 executes a predetermined still image capturing process. This still image capturing process is the same as the conventional general process, and detailed description thereof is omitted. Thereafter, the processing returns to step S101, and the subsequent processing is repeated.

As described above, according to the first embodiment, when the AF instruction signal is generated by the first (1st.) Release operation or the like, the focus is adjusted by the previous focus adjustment operation. If it is estimated that the in-focus state is maintained, an image plane phase difference AF process capable of executing the AF control process at high speed without lens driving is selected and automatically executed. I have to. On the other hand, when the AF instruction signal is generated, if it is in the out-of-focus state, a contrast AF control process capable of reliably detecting the focus state while driving the lens is executed. In other words, according to the present embodiment, based on the history of the focus adjustment operation, control is performed to switch between contrast AF processing that always involves lens driving and image plane phase difference AF processing that does not always accompany. Accordingly, it is possible to automatically select and switch an appropriate focus adjusting unit according to the situation, and it is possible to always perform a photographing operation by high-speed AF control processing.
[Second Embodiment]

  The second embodiment of the present invention is basically substantially the same as the first embodiment described above, and only a part of the processing sequence is different. That is, in this embodiment, the subroutine (see FIG. 9) in the single AF mode is slightly different. Therefore, in the second embodiment described below, the description of the same configuration and operation as those in the first embodiment is omitted. The same processing steps as those in the first embodiment described above are denoted by the same processing numbers and description thereof is omitted, and only different processing steps will be described below.

  The main flowchart of this embodiment is substantially the same as FIG. 6 described in the first embodiment. In the main flowchart of FIG. 6, after confirming the first release operation, when the setting of the single AF mode is confirmed in the process of step S113, the single AF mode process (step S300 of FIG. 6; FIG. 8 for details) is executed. The

  FIG. 9 shows a subroutine of single AF mode processing in the present embodiment. This is a process corresponding to step S300 (detailed diagram 8) of FIG. 6 in the first embodiment.

  In the single AF mode process (the process in step S300A) of the present embodiment, as shown in FIG. 9, first, in step S301, the setting of the image plane phase difference AF processable area (area) is confirmed. When the setting of the image plane phase difference AF processable area is confirmed, the process proceeds to an AF method selection determination process (details will be described later, a subroutine of FIG. 10) in step S500. If the same setting is not confirmed, the process proceeds to step S303.

  After the process of step S500 (FIG. 10), returning to FIG. 9 and proceeding to the process of step S302A, in this step S302A, the signal processing control unit 11 indicates that the selection determination result in the process of step S500 is “image plane position”. It is confirmed whether or not it is “phase difference AF”. If the determination result is “image plane phase difference AF”, the process proceeds to the image plane phase difference AF process in step S304. If the determination result is not “image plane phase difference AF”, the process proceeds to contrast AF processing in step S303.

  The subsequent steps S303 to S308 are the same as the steps S303 to S308 in FIG. As in the sequence of FIG. 8, the acquired various types of information data are temporarily stored in, for example, the SDRAM 17 or a temporary memory unit (not shown) of the signal processing control unit 11. Thereafter, the series of processes is terminated and the process returns to the original process sequence (return).

  Here, the details of the AF method selection determination process, which is a process for selecting the AF control process according to the situation and determining the AF method to be employed, will be described below with reference to FIGS. Explained.

  As described above, when the AF method selection determination process is executed under the control of the signal processing control unit 11, first, in step S600 of FIG. 10, the signal processing control unit 11 determines that the current lens position is the in-focus position. In-focus vicinity determination processing is performed to determine whether or not the object is in the vicinity. Details of the in-focus vicinity determination process are shown in the subroutine of FIG. Here, the focus vicinity determination is determination of whether or not the current lens position is in the vicinity of the focus position. In other words, being in focus is equivalent to a case where the defocus amount is “small”. In other words, if the focus is not in focus, that is, not in the vicinity of focus, the defocus amount is “large”. Corresponds to the case.

  The in-focus vicinity determination process is a process executed under the control of the signal processing control unit 11. Therefore, in this case, the signal processing control unit 11 functions as an in-focus vicinity determination unit.

  In step S601 in FIG. 11, the signal processing control unit 11 checks whether or not the current contrast value has changed from the contrast value at the time of final focusing (the value acquired in step S307 in FIG. 9). If no change is confirmed, the process proceeds to step S606. If a change is confirmed, the process proceeds to step S602.

  In step S602, the signal processing control unit 11 checks whether or not the elapsed time from the time of the final focusing is within a predetermined time. This confirmation is performed based on the time of focusing obtained and recorded in step S308 of FIG. 9 and the elapsed time obtained with reference to the clock unit 15. Here, when it is confirmed that the elapsed time from the final focusing time is within a predetermined time, the process proceeds to step S606. On the other hand, if the elapsed time from the final focusing time exceeds the predetermined time, the process proceeds to step S603.

  In step S603, the signal processing control unit 11 matches the image pattern in the current in-focus area with the in-focus area image pattern (the image pattern recorded in step S306 in FIG. 9) at the time of the final in-focus. Check if it exists. If the image pattern match is confirmed, the process proceeds to step S606. If the image pattern mismatch is confirmed, the process proceeds to step S604.

  In step S604, the signal processing control unit 11 confirms the posture change of the camera 1 based on the outputs from the angular velocity sensor 22, the acceleration sensor 23, etc., and the posture change information recorded in the process of step S111 in FIG. Compare and check for any changes in posture. If a change in posture is confirmed, the process proceeds to step S605. If no posture change is confirmed, the process proceeds to step S606.

  In step S605, the signal processing control unit 11 determines that the current lens position is not in the vicinity of the in-focus position (is in the out-of-focus position), and ends the series of processes (return).

  In step S606, the signal processing control unit 11 determines that the current lens position is in the vicinity of the in-focus position, and ends a series of processing (return).

  Returning to FIG. 10, in step S <b> 501, the signal processing control unit 11 checks whether or not the result of the processing in step S <b> 600 described above is close to the in-focus state. If it is near the in-focus state, the process proceeds to step S506.

  On the other hand, if it is not near focus (near out-of-focus) in the process of step S501 described above, the process proceeds to step S502.

  In step S502, the signal processing control unit 11 checks whether or not the main subject image to be photographed on the imaging surface is a moving object. This confirmation is performed based on an image recognition technique using the image processing unit 11c or the like, or a detection result by the image movement amount detection unit 11f or the like. If it is confirmed that the subject image is a moving object, the process proceeds to step S506. If the subject image is not a moving object, the process proceeds to step S700.

  In step S <b> 700, the signal processing control unit 11 performs a phase difference reliability prior determination process for determining in advance the reliability of the phase difference AF process. Details of this phase difference reliability prior determination processing are shown in the subroutine of FIG.

  The phase difference reliability prior determination process is a process executed under the control of the signal processing control unit 11. Therefore, in this case, the signal processing control unit 11 functions as a phase difference reliability prior determination unit.

  In step S701 in FIG. 12, the signal processing control unit 11 confirms whether or not there is a defocus amount of the current subject image on the imaging surface. Here, when there is a defocus amount, it is a case where it is not in focus. In this case, the process proceeds to step S702. If there is no defocus amount, that is, if it is in focus, the process proceeds to step S703.

  In step S702, the signal processing control unit 11 confirms the specifications of the lens barrel 30 currently mounted. That is, it is confirmed whether or not the lens barrel 30 is a wide-angle lens having an aperture value smaller than F4 and a focal length of 20 mm or less. This confirmation is due to the following reason. In general, in the specification of the lens barrel 30 constituting the photographing optical system, the depth of field tends to be deeper as the open aperture value is smaller and the focal length is shorter. It is well known that the above in-focus range, that is, the in-focus range is widened. In this case, the range in the in-focus range (the range in which the in-focus state is achieved) can be represented by an allowable range of the amount of deviation in the optical axis direction of the lens position with respect to the focus position. Therefore, in the present embodiment, in the specification of the lens barrel 30, a sufficiently deep depth of field is obtained if the wide-angle lens has an aperture value smaller than F4 and a focal length of 20 mm or less. Therefore, the reliability of the focus adjustment process can be obtained.

  If it is determined in step S702 that the lens barrel 30 meets the same condition (smaller than the open aperture F4 and equal to or less than 20 mm in focal length), the process proceeds to step S703. If the condition is not met, the process proceeds to step S704.

  In step S703, the signal processing control unit 11 determines in advance that a reliable focus adjustment result is obtained when the AF control processing by the image plane phase difference AF processing is performed in the current situation (reliability A determination of presence), a series of processing ends (return).

  In step S704, the signal processing control unit 11 determines in advance that a reliable focus adjustment result cannot be obtained when the AF control processing by the image plane phase difference AF processing is performed in the current situation (reliable). A series of processing ends (return).

  Returning to FIG. 10, in step S <b> 503, the signal processing control unit 11 checks whether or not the processing result in step S <b> 700 described above is a reliable prior determination. Here, if the determination is reliable, the process proceeds to step S506. If the prior determination is not reliable, the process proceeds to step S800.

  In step S800, the signal processing control unit 11 executes AF time estimation processing. In this AF time estimation processing, the processing time (Tp) required when the image plane phase difference AF processing is performed and the processing time (Ti) required when the contrast AF processing is performed are calculated (estimated) in advance. It is processing. The details are shown in the subroutine of FIG.

  The AF time estimation process is a process executed under the control of the signal processing control unit 11. Therefore, in this case, the signal processing control unit 11 functions as an AF time estimating unit.

  In step S801 in FIG. 13, the signal processing control unit 11 checks whether or not there is a frame rate switching time.

  When executing the AF control process from a state where normal live view image display is being performed, for example, in order to speed up the AF control process by speeding up the reading of image data from the image sensor 12a, the image sensor 12a The frame rate may be switched in the high speed direction, for example, from 60 fps to 120 fps. When this frame rate is switched, a blank period for one frame is required to adjust the data reading timing. The time required for this period is referred to as frame rate switching time.

  If the frame rate switching time exists, the process proceeds to step S803, where the frame rate switching time is set to Tsw. Thereafter, the process proceeds to step S804.

  On the other hand, if the frame rate switching time does not exist, the process proceeds to step S802, and the frame rate switching time Tsw = 0 is set in step S802. Thereafter, the process proceeds to step S804.

  In step S804, the signal processing control unit 11 acquires the contrast AF processing time (Tli) from the current lens position.

  Next, in step S805, the signal processing control unit 11 acquires Ti = Tsw + Tli as a result of estimating the contrast AF processing time.

  Subsequently, in step S806, the signal processing control unit 11 acquires the image plane phase difference AF processing time (Tlp) from the current lens position.

  Next, in step S807, the signal processing control unit 11 acquires Tp = Tsw + Tlp as an estimation result of the image plane phase difference AF processing time. Thereafter, the series of processes is terminated (return).

  Returning to FIG. 10, in step S504, the signal processing control unit 11 calculates the estimated time between the contrast AF processing time (Ti) and the image plane phase difference AF processing time (Tp) acquired in the processing in step S800 described above. Make a comparison. Here, it is confirmed whether or not image plane phase difference AF processing time (Tp) <contrast AF processing time (Ti). If so, the process proceeds to step S506. Otherwise, the process proceeds to step S505.

  In step S505, the signal processing control unit 11 performs a predetermined contrast AF process. Thereafter, the series of processes is terminated (return).

  On the other hand, in step S506, the signal processing control unit 11 executes image plane phase difference AF processing. Details of this image plane phase difference AF processing are shown in the subroutine of FIG.

  In step S5061 in FIG. 14, the signal processing control unit 11 checks whether the defocus amount can be calculated. If it is confirmed that the defocus amount can be calculated, the process proceeds to step S5062. If the defocus amount cannot be calculated, the process proceeds to step S5063.

  In step S5062, the signal processing control unit 11 executes lens drive control toward the in-focus position. Thereafter, the series of processes is terminated (return).

In step S5063, the signal processing control unit 11 executes lens drive control toward the closest end or the infinity end in the focus adjustable range. Thereafter, the series of processes is terminated (return).
As described above, also in the second embodiment, the same effects as those in the first embodiment can be obtained. In addition to this, in this embodiment, an AF method selection determination process (FIG. 12) including a process for determining the reliability of the image plane phase difference AF process in advance (FIG. 12), an AF time estimation process (FIG. 13), and the like. 10), the optimum AF method can be automatically selected and executed according to the situation. Therefore, it is possible to obtain an imaging apparatus that can always perform high-speed AF processing and perform comfortable shooting.

  Each processing sequence described in each of the above-described embodiments can allow a procedure to be changed as long as it does not contradict its nature. Therefore, for each of the above-described processing sequences, for example, the order of the processing steps is changed each time the processing order is changed, the processing steps are executed simultaneously, or a series of processing sequences are executed. It may be.

  That is, regarding the operation flow in the claims, the specification, and the drawings, even if it is described using “first,” “next,” etc. for convenience, it is essential to carry out in this order. It doesn't mean. In addition, it goes without saying that the steps constituting these operation flows can be omitted as appropriate for portions that do not affect the essence of the invention.

  Of the technologies described here, many of the controls and functions mainly described in the flowcharts can be set by a program, and the above-described controls and functions can be realized by a computer reading and executing the program. it can. As a computer program product, the program may be recorded or stored in whole or in part on a portable medium such as a non-volatile memory such as a flexible disk or a CD-ROM, or a storage medium such as a hard disk or a volatile memory. It can be distributed or provided at the time of product shipment or via a portable medium or communication line. The user can easily realize the photographing apparatus of the present embodiment by downloading the program via a communication network and installing the program in a computer or installing the program from a recording medium into the computer.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and applications can of course be implemented without departing from the spirit of the invention. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if several constituent requirements are deleted from all the constituent requirements shown in the above-described embodiment, if the problem to be solved by the invention can be solved and the effect of the invention can be obtained, this constituent requirement is deleted. The configured structure can be extracted as an invention.

1 …… Camera,
DESCRIPTION OF SYMBOLS 10 ... Camera body, 11 ... Signal processing control part, 11b ... AF signal calculation part, 11c ... Image processing part, 11d ... Exposure control part, 11e ... Distance calculation operation part, 11f ... Image movement amount Detection unit, 11g ... Operation control unit, 12 ... Imaging unit, 12a ... Imaging element, 12b ... Pixel addition readout unit, 12c ... Non-pixel addition readout unit, 13 ... Flash memory, 14 ... Face detection 15, clock unit 16, operation unit 18, display device, 19 display driver, 20 touch panel, 21 touch panel driver, 22 angular velocity sensor, 23 acceleration sensor, 24 ...... Recording medium, 25 ... Memory interface, 26 ... Body side communication unit,
30 ... Lens barrel, 31 ... Lens control unit, 32 ... Lens driver, 33 ... Optical lens, 34 ... Aperture device, 41 ... Interface,

Claims (6)

An imaging optical system including a lens for forming a subject image;
An imaging device in which imaging pixels are arranged two-dimensionally over the entire imaging surface, and a plurality of focus detection pixels are arranged in at least a part of the arrangement;
First focus adjusting means for performing focus adjustment based on an output signal from the imaging pixel;
Second focus adjusting means for performing focus adjustment based on an output signal from the focus detection pixel;
According to the situation, based on the determination result by the AF method selection determination unit that determines the selection of any one of the first focus adjustment unit and the second focus adjustment unit, and the determination result by the AF method selection determination unit. and switching means for switching between said first focusing means and the second focusing means, and a control unit having a,
Comprising
The AF method selection determination means in the control unit has an area setting for performing autofocus processing by the second focus adjustment means when receiving an instruction signal for starting a focus adjustment operation , and the lens is If it is in the in-focus position, it is determined to select the second focus adjusting means ,
The switching device in the control unit switches to the second focus adjustment unit when the AF method selection determination unit determines to select the second focus adjustment unit . The first focus adjustment means performs focus adjustment by an automatic focus adjustment control process of a contrast detection method,
The image pickup apparatus according to claim 1, wherein the second focus adjustment unit performs focus adjustment by an automatic focus adjustment control process of an imaging surface phase difference detection method. The AF method selection determining means in the control unit determines whether the current lens position is a focus position based on at least one of the information of the contrast value in the final focus state, the elapsed time, and the image pattern of the AF area. the focus proximity determination means for determining whether the vicinity of, further comprising, according to claim 1, characterized in that selecting an appropriate AF method in accordance with the determination result of the above Kigoase proximity determination means Imaging device. The AF method selection determination means in the control unit is configured to adjust the second focus adjustment based on information on at least one or both of a defocus amount acquired by the second focus adjustment means and specification data of the imaging optical system. a phase difference reliability advance determination means for determining in advance the reliability of the focusing result by means, further comprising, selecting an appropriate AF method in accordance with the determination result of the above SL retardation reliable advance judging means The imaging apparatus according to claim 1, wherein the imaging apparatus is characterized. The AF method selection determination unit in the control unit acquires the processing time by the first focus adjustment unit from the current lens position and the processing time by the second focus adjustment unit from the current lens position, respectively. the AF time estimation means further comprises, by comparing the processing times obtained by the above Symbol AF time estimating means, the imaging apparatus according to claim 1, characterized in that to select the appropriate AF method. Whether the current lens position is in the vicinity of the in-focus position based on at least one of the contrast value, the elapsed time, and the AF area image pattern information at the time of the final in-focus state by the in-focus vicinity determination unit Determine whether
The focus adjustment result by the second focus adjustment unit based on at least one or both of the defocus amount acquired by the second focus adjustment unit and the specification data of the imaging optical system by the phase difference reliability prior determination unit The reliability of the
The AF time estimating means, and processing time by the first focusing means from the current lens position, respectively obtains the processing time by the second focusing means from the current lens position,
The control unit selects an appropriate AF method in accordance with the processing time acquired by the determination result, or the AF time estimating means of the focus proximity determination means or the retardation reliable advance determining means,
The AF method is selected as follows:
When it is determined by the in-focus vicinity determining means that the current lens position is in the vicinity of the in-focus position, or according to each determination result in the phase difference reliability prior determination means, the focus adjustment by the second focus adjusting means When it is determined that the result is reliable, or when the processing time by the second focus adjustment unit acquired by the AF time estimation unit is a predetermined processing time by the first focus adjustment unit In one case, when it is determined that any one of the above three cases, the AF method is selected as the second focus adjustment unit, and otherwise, the first focus adjustment unit is selected. A control method for an image pickup apparatus.

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