JP2018200481A - Imaging device - Google Patents

Abstract

To save power while maintaining the accuracy of focus adjustment during focus adjustment based on extraction of a main subject area.SOLUTION: An imaging device includes: an imaging unit having a first mode for taking a subject image and generating composition confirmation image data and a second mode for taking a subject image and generating record image data; an area detection unit for calculating a feature quantity of an image indicated by the composition confirmation image data and detecting a specific area on the basis of the feature quantity; and a control unit for executing preparation operation for imaging on the basis of information calculated from the specific area detected by the area detection unit before the imaging unit starts imaging in the second mode.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an imaging apparatus.

  Conventionally, various techniques relating to focus adjustment have been considered. For example, the invention of Patent Document 1 discloses an imaging apparatus that performs focus adjustment using a subject extraction technique. In the invention of Patent Document 1, it is possible to optimally perform automatic focus adjustment on a subject even when the subject moves in the camera direction by deforming the AF distance measurement frame in accordance with the amount of change in the subject shape. Yes.

JP 2009-069748 A

  By the way, various techniques have been considered for continuous AF that continuously adjusts the focus of a moving subject. However, accurate continuity cannot be maintained with respect to changes in the angle of view. There were many cases. Therefore, when the AF evaluation value changes, it is necessary to perform rescanning. Further, since the lens control is based on the above-described AF evaluation value, there are many problems that unnecessary driving is performed and driving is not performed when necessary. Furthermore, continuous AF also has a problem of high power consumption.

  The present invention has been made in view of the above points, and an object thereof is to realize power saving while maintaining the accuracy of focus adjustment when performing focus adjustment based on extraction of a main subject region.

  An imaging apparatus of the present invention includes an imaging unit having a first mode for capturing a subject image and generating composition confirmation image data, and a second mode for capturing the subject image and generating recording image data; A feature amount of an image indicated by the composition confirmation image data is calculated, a region detection unit that detects a specific region based on the feature amount, and the region before the imaging unit captures an image in the second mode. And a control unit that executes an imaging preparation operation based on information calculated from the specific area detected by the detection unit.

  The control unit may calculate distance measurement information from the composition confirmation image data of the specific area detected by the area detection unit.

  The imaging unit captures the subject image incident via an optical system to generate the composition confirmation image data and the recording image data, and the control unit performs the optical system as the preparation operation. Operations including focusing control related to the above may be executed.

  Further, the control unit may execute an operation including a change of a lens position of the optical system as the focusing control.

  In addition, a reception unit that receives a mode switching instruction for switching from the first mode to the second mode is further included, and when the control unit receives the mode switching instruction, the focus is based on the distance measurement information in the second mode. Imaging may be performed by changing the lens position to a position.

  In addition, the image processing apparatus further includes a reception unit that receives a mode switching instruction for switching from the first mode to the second mode, and the control unit includes the lens position at a position near a focus position based on the distance measurement information as the preparation operation. When the mode switching instruction is accepted, the image is captured without changing the lens position in the second mode, or the lens position is changed to the in-focus position in the second mode. May be performed.

  In addition, a reception unit that receives a mode switching instruction for switching from the first mode to the second mode is further provided, and the control unit performs a first focusing control based on the distance measurement information as the first operation and performs a first focusing control. When the lens position is changed to the in-focus position or the first in-focus control based on the distance measurement information is performed to change the lens position to a position near the first in-focus position, and the mode switching instruction is accepted In the vicinity of the current lens position, the second focus control with higher accuracy than the first focus control may be performed to change the lens position to the second focus position.

  In addition, the image processing apparatus further includes a reception unit that receives a mode switching instruction for switching from the first mode to the second mode, and the control unit changes the lens position to a focus position based on the distance measurement information as the preparation operation. When the mode switching instruction is received, imaging may be performed without changing the lens position in the second mode.

In addition, a storage unit that stores the distance measurement information obtained by the control unit,
The control unit continuously calculates the ranging information until receiving the mode switching instruction, and updates the ranging information by storing the calculated ranging information in the storage unit. Also good.

  The distance measurement information includes information indicating whether it is a front pin or a rear pin with respect to the in-focus position, and the distance measurement information is detected from wobbling or axial aberration in contrast AF. The phase difference AF may correspond to phase difference information.

  According to the present invention, when performing focus adjustment based on extraction of a main subject region, it is possible to realize power saving while maintaining the accuracy of focus adjustment.

2 is a block diagram illustrating configurations of a lens barrel 10, an imaging device 20, and a storage medium 40. FIG. It is a flowchart which shows operation | movement of CPU26 at the time of automatic detection mode execution. It is a figure explaining AF at the time of automatic detection mode execution. It is another flowchart which shows operation | movement of CPU26 at the time of automatic detection mode execution. It is another flowchart (continuation) which shows operation | movement of CPU26 at the time of automatic detection mode execution. It is a figure explaining a focus shift at the time of automatic detection mode execution.

<First Embodiment>
Hereinafter, a first embodiment will be described in detail with reference to the drawings.

  In the first embodiment, a description will be given by taking as an example an apparatus including a lens barrel 10, an imaging device 20, and a storage medium 40 as shown in FIG.

  The imaging device 20 captures an optical image incident from the lens barrel 10. The obtained image is stored in the storage medium 40 as a still image or a moving image.

  The lens barrel 10 includes a focus adjustment lens (hereinafter referred to as an “AF (Auto Focus) lens”) 11, a lens driving unit 12, an AF encoder 13, and a lens barrel control unit 14. The lens barrel 10 may be detachably connected to the imaging device 20 or may be integrated with the imaging device 20.

  The imaging device 20 includes an imaging unit 21, an image processing device 22, a display unit 23, a buffer memory unit 24, a storage unit 25, a CPU 26, an operation unit 27, and a communication unit 28. The imaging unit 21 includes an imaging element (not shown), and is controlled by the CPU 26 according to set imaging conditions (for example, an aperture value, an exposure value, etc.).

  In the lens barrel 10, the AF lens 11 is driven by the lens driving unit 12, and guides an optical image to a light receiving surface (photoelectric conversion surface) of an imaging element (not shown) in the imaging unit 21 of the imaging device 20. The AF encoder 13 detects the movement of the AF lens 11 and outputs a signal corresponding to the movement amount of the AF lens 11 to the lens barrel control unit 14. Here, the signal corresponding to the movement amount of the AF lens 11 may be, for example, a sine wave signal whose phase changes according to the movement amount of the AF lens 11.

  The lens barrel control unit 14 controls the lens driving unit 12 in accordance with a drive control signal input from the CPU 26 of the imaging device 20. Here, the drive control signal is a control signal for driving the AF lens 11 in the optical axis direction. The lens barrel control unit 14 changes, for example, the number of steps of the pulse voltage output to the lens driving unit 12 according to the drive control signal. Further, the lens barrel control unit 14 outputs the position (focus position) of the AF lens 11 in the lens barrel 10 to the CPU 26 of the imaging device 20 based on a signal corresponding to the movement amount of the AF lens 11. Here, the lens barrel control unit 14 integrates, for example, signals according to the movement amount of the AF lens 11 according to the movement direction of the AF lens 11, thereby moving the AF lens 11 in the lens barrel 10 ( Position) may be calculated. The lens driving unit 12 drives the AF lens 11 according to the control of the lens barrel control unit 14 and moves the AF lens 11 in the optical axis direction within the lens barrel 10.

  In the imaging device 20, the imaging unit 21 may include, for example, an imaging element that converts an optical image formed on the photoelectric conversion surface by the lens barrel 10 (optical system) into a digital signal and outputs the digital signal. good. In addition, for example, the imaging unit 21 includes an imaging device and an A / D conversion unit, and the imaging device converts an optical image formed on the photoelectric conversion surface by the lens barrel 10 (optical system) into an electrical signal and converts it into an A signal. The A / D converter may output to the / D converter, and the A / D converter may digitize the electrical signal converted by the image sensor and output the digital signal. Note that the imaging element is configured by a photoelectric conversion element such as a CMOS (Complementary Metal Oxide Semiconductor), for example. Further, the image sensor may convert an optical image into an electric signal for a partial region of the photoelectric conversion surface (image clipping). Further, the imaging unit 21 outputs a recording image obtained when a shooting instruction from the user is received via the operation unit 27 to the storage medium 40 via the communication unit 28. On the other hand, the imaging unit 21 outputs continuously obtained images to the buffer memory unit 24 and the display unit 23 as through images in a state before receiving a shooting instruction from the user via the operation unit 27.

  The image processing device 22 performs image processing on the image temporarily stored in the buffer memory unit 24 based on the image processing conditions stored in the storage unit 25. The image after image processing is stored in the storage medium 40 via the communication unit 28. Further, the image processing device 22 performs mask extraction processing on the image temporarily stored in the buffer memory unit 24 (details will be described later). The extracted mask information is output to the CPU 26 and stored in the storage unit 25, the storage medium 40, and the like.

  The display unit 23 is, for example, a liquid crystal display, and displays an image generated by the imaging unit 21, an operation screen, and the like. The buffer memory unit 24 temporarily stores the image generated by the imaging unit 21. The storage unit 25 stores imaging conditions, determination conditions referred to by the CPU 26 in various determinations, and the like.

  The CPU 26 acquires necessary information as appropriate from the image processing device 22, the storage unit 25, and the like, and comprehensively controls each unit in the imaging device 20 based on the acquired information. Control by the CPU 26 includes focus adjustment (AF) setting, exposure adjustment (AE) setting, white balance adjustment (AWB) setting, flash emission amount change setting, subject tracking setting, and various shooting mode settings. , Various image processing settings, various display settings, brightness optimization settings linked to zoom magnification, and the like. In addition, the CPU 26 monitors the operation state of the operation unit 27 and outputs image data to the display unit 23.

  The operation unit 27 includes, for example, a power switch, a shutter button, a multi-selector (cross key), or other operation keys. The operation unit 27 receives a user operation input when operated by the user, and outputs a signal corresponding to the operation input to the CPU 26. Output to.

  The communication unit 28 is connected to a removable storage medium 40 such as a card memory, and writes, reads, or deletes information (image data, area information, etc.) to the storage medium 40.

  The storage medium 40 is a storage unit that is detachably connected to the imaging device 20 and stores information (image data, area information, and the like). Note that the storage medium 40 may be integrated with the imaging device 20.

  The imaging device 20 includes an automatic detection mode for automatically detecting a specific area in addition to a normal mode for detecting a specific area (for example, a main subject area or a region of interest) based on focus adjustment information during shooting. The automatic detection mode is a mode in which a specific region is automatically and continuously detected based on a through image for composition confirmation and the like, and each unit is controlled based on information on the detected specific region. This automatic detection mode may be set by a user operation via the operation unit 27, or may be automatically set by the CPU.

  The operation of the CPU 26 when executing the automatic detection mode for detecting the main subject area as the specific area will be described below with reference to the flowchart of FIG.

  In step S <b> 101, the CPU 26 controls the imaging unit 21 to start acquiring a through image. The acquired image information of the through image is temporarily stored in the buffer memory unit 24. This through image is continuously generated at a predetermined time interval. The acquisition of the through image by the CPU 26 is sequentially performed sequentially in time.

  In step S102, the CPU 26 controls the image processing device 22 to perform normal image processing. Normal image processing includes white balance adjustment, interpolation processing, color tone correction processing, gradation conversion processing, and the like. Since the specific method of each process is the same as that of a well-known technique, description is abbreviate | omitted. The image processing device 22 acquires the image data of the target image from the buffer memory unit 24, performs image processing, and then outputs the image data to the buffer memory unit 24 again.

  In step S103, the CPU 26 controls the image processing device 22 to perform mask extraction processing. The mask extraction process is a technique for calculating a feature amount in an image and detecting a main subject region based on the feature amount. For example, the mask extraction is performed by obtaining an evaluation value from the feature amount in the image and obtaining a continuous region having the same evaluation value. Any method of mask extraction may be used. In addition, since a specific method for extracting a mask is the same as that of a known technique, description thereof is omitted.

  In step S104, the CPU 26 determines whether or not the subject area has been extracted by the mask extraction. The CPU 26 determines whether or not the mask extraction by the mask extraction process in step S103 is successful. If the feature amount cannot be calculated or the evaluation value is too low in the mask extraction process in step S103, the CPU 26 It is determined that the extraction has failed and the subject area cannot be extracted, and the normal image processing in step S102 and the mask extraction processing in step S103 are repeated. On the other hand, if the CPU 26 determines that the mask extraction by the mask extraction process in step S103 is successful, the process proceeds to step S105.

  In step S105, the CPU 26 records the result of the mask extraction process in the buffer memory unit 24, the storage unit 25, or the like as mask information. The mask information includes information such as the extraction conditions (color classification, mask classification, etc.) of the mask extraction process in step S103, the position of the mask, and the size and shape of the mask. The CPU 26 may control the display unit 23 to display information on the main subject area extracted by the mask extraction in step S103 on the display unit 23. For example, the CPU 26 can display the main subject area so as to be visible by superimposing it on the through image and displaying a frame or the like in the main subject area. The frame may be in accordance with the shape of the main subject area, or may be a predetermined shape such as a rectangle or a circle. Also, the line thickness, shading, color, etc. may be anything. In any case, by performing such display, the user can easily grasp the result of the mask extraction process performed by the CPU 26.

  In step S106, the CPU 26 determines whether or not the same mask has been extracted continuously n times (n frames) or more. If the CPU 26 determines that the same mask has been extracted continuously n times or more, the CPU 26 proceeds to step S107 described later. On the other hand, when determining that the same mask has not been extracted n times or more in succession, the CPU 26 returns to step S102 described above, and performs the processing from step S102 onward for the next through image.

  The case where the same mask is extracted is a case where masks of substantially the same color and size are extracted at substantially the same position in a plurality of frames. For this determination, the mask information described in step S105 may be used. In any case, when the amount of change between frames is within a specified range, it can be determined that they are the same. Based on the mask information or the like described in step S105, the tendency of mask extraction performed in the past (extracted mask type, appearance frequency, etc.) is obtained, and the amount of change described above is within the specified range according to this tendency. It may be possible to appropriately change the threshold for determining whether or not. For example, the threshold value may be changed to a larger value for a mask extracted at a high frequency in the past.

  Note that n described above is a predetermined threshold (for example, n = 7), and is appropriately determined based on the frame rate at the time of image capturing by the image capturing unit 21, the zoom magnification in the lens barrel 10, the user operation via the operation unit 27, and the like. It may be changeable. Further, the tendency of mask extraction performed in the past (the type of extracted mask, the appearance frequency, etc.) is obtained based on the mask information described in step S105, and the value of n described above is appropriately set according to this tendency. It may be changeable. For example, for a mask extracted at a high frequency in the past, the value of n may be changed to a smaller value.

  Further, the contents of the determination made in step S106 may be recorded in addition to the mask information described in step S105, and used in subsequent processing relating to frames.

  Moreover, it is good also as a structure which determines whether the mask extraction process is performed stably by methods other than the above-mentioned. For example, the determination may be performed in consideration of whether the same mask has been extracted continuously until the previous time. With this configuration, even if temporary unextraction occurs only this time, if the same mask is extracted in the next frame without invalidating the previous accumulation, the previous stable state is maintained. Can be considered.

  In step S107, the CPU 26 determines whether or not the first AF for the mask extracted by the mask extraction process in step S103 (hereinafter referred to as “extraction mask”) is completed. Details of the first AF will be described later in step S111. When the CPU 26 determines that the first AF has been completed, the CPU 26 proceeds to step S112 described later. On the other hand, when determining that the first AF has not been completed, the CPU 26 proceeds to step S108.

  In step S108, the CPU 26 sets an area corresponding to the extraction mask extracted by the mask extraction process in step S103 as a main subject area. The CPU 26 may control the display unit 23 to display information on the set main subject area on the display unit 23. For example, the main subject area may be displayed so as to be visible by displaying a frame or the like in the set main subject area.

  In step S109, the CPU 26 sets the main subject region set in step S108 as a contrast evaluation target.

  In step S110, the CPU 26 controls the lens driving unit 12 via the lens barrel control unit 14, performs wobbling by moving the AF lens 11 in the optical axis direction, and determines the focus direction. The specific method of wobbling and the process for obtaining the focus direction based on wobbling are performed in the same manner as in the known art. Instead of wobbling, the focus direction may be determined based on the axial aberration of the AF lens 11.

  In step S111, the CPU 26 executes the first AF for the extraction mask extracted by the mask extraction process in step S103. The CPU 26 controls the lens driving unit 12 via the lens barrel control unit 14, and moves the AF lens 11 in the focus direction determined in step S 110 to the contrast evaluation value from the contrast evaluation target set in step S 109. Based on this, the first AF is executed.

  Here, the first AF will be described with reference to FIG. The vertical axis in FIG. 3 indicates the contrast evaluation value, and the horizontal axis indicates the lens position of the AF lens 11. FIG. 3A is a diagram illustrating normal AF. The vertical solid line in the graph indicates the pitch at which AF is performed. FIG. 3B is a diagram for describing the first AF executed in step S111. As shown in FIG. 3B, in the first AF, AF with relatively coarse accuracy is executed at a pitch about ¼ of normal AF. This is to finish AF in as short a time as possible, and with this first AF, a rough peak position can be grasped.

  The CPU 26 sets the intermediate point between two points (P1 and P2 in FIG. 3B) that can be estimated to be close to the peak as a temporary peak Pt, and controls the lens driving unit 12 via the lens barrel control unit 14 to temporarily set the AF lens 11. Move to the peak Pt to finish the first AF.

  The first AF described above is an example, and the first AF may be executed in consideration of information such as the degree of change in contrast evaluation value, the position of the extraction mask, and the size of the extraction mask.

  In step S112, the CPU 26 determines whether or not a shooting instruction has been issued. If the CPU 26 determines that a shooting instruction has been given, the process proceeds to step S113. On the other hand, if it is determined that the shooting instruction is not issued even after a predetermined time has elapsed, the CPU 26 returns to step S102 described above, and performs the processing from step S102 onward for the next through image. The photographing instruction is performed by a user operation via the shutter button of the operation unit 27. This user operation may be a so-called half shutter or all shutter. The shutter button of the operation unit 27 has, for example, a two-stage switch. When the shutter button is pressed (half-pressed) to the first stage, it is a half-shutter. When the shutter button is pressed (full-pressed) to the second stage, the shutter button is all. It is a shutter. In the present embodiment, an instruction to switch from a mode for generating through image data for composition confirmation to a mode for generating image data for recording is performed by a half shutter operation or full shutter operation by a user.

  In step S113, the CPU 26 executes AE and AWB based on the information on the main subject area set in step S108.

  In step S114, the CPU 26 moves the lens position of the AF lens 11 to the near side of the focus range. The CPU 26 sets the focus range between two points (P1 and P2 in FIG. 3B) that can be estimated to be close to the peak in the first AF executed in step S111, and controls the lens driving unit 12 via the lens barrel control unit 14. Then, the AF lens 11 is moved to the near side of the focus range (P1 in FIG. 3B). Instead of moving the AF lens 11 to the near side of the focus range, the AF lens 11 may be moved to the far side of the focus range (P2 in FIG. 3B).

  In step S115, the CPU 26 executes the second AF. FIG. 3C is a diagram for describing the second AF executed in step S115. As shown in FIG. 3C, in the second AF, the AF is executed with the same degree of pitch as the normal AF, that is, with higher accuracy than the first AF in the focus range described in step S114. This is because the rough peak position is grasped by the first AF executed in step S111, so that the accurate AF is finally executed by executing AF with appropriate accuracy only in the vicinity of the second AF. This is because it can be done.

  If the AF lens 11 is moved to the near side of the focus range in step S114, the second AF is executed from P1 to P2, and the AF lens 11 is moved to the far side of the focus range. If so, the second AF is executed from P2 to P1.

  The CPU 26 determines the peak by the second AF within the focus range, controls the lens driving unit 12 via the lens barrel control unit 14, moves the AF lens 11 to the peak, and ends the second AF.

  In step S116, the CPU 26 controls each unit to perform shooting. At this time, the CPU 26 determines various image processing conditions and the like in the image processing device 22 based on the main subject region set in step S108.

  In step S117, the CPU 26 records an image generated by imaging on the storage medium 40 via the communication unit 28, and ends the series of processes.

  As described above, according to the first embodiment, the first mode in which the subject image is captured and the composition confirmation image data is generated, and the second mode in which the subject image is captured and the recording image data is generated. And an area detection unit that calculates a feature amount of an image indicated by the composition confirmation image data and detects a specific region based on the feature amount. Then, before the imaging unit performs imaging in the second mode, an imaging preparation operation is executed based on information calculated from the specific area detected by the area detection unit. Therefore, with the above-described configuration, a certain amount of preparation operation can be performed during composition confirmation before imaging is performed in the second mode for generating image data for recording. In addition to contributing to shortening the shooting time lag, it is possible to achieve power saving while maintaining the accuracy of focus adjustment when performing focus adjustment based on the extraction of specific areas such as the main subject area and the attention area. it can.

  Conventionally, when AF is performed after an instruction to perform imaging in the second mode for generating image data for recording, the imaging time lag is usually increased. This is conspicuous in contrast AF. However, according to the first embodiment, while the user before the imaging instruction in the second mode performs framing or the like, the distance measurement information is acquired, the focus control is performed, and the like in the second mode. The shooting time lag can be shortened by using the distance measurement information described above even after the imaging instruction. In addition, according to the first embodiment, since lens driving after an imaging instruction in the second mode can be minimized, stability can be improved and AF accuracy and power saving can be compatible. is there.

  Further, according to the first embodiment, a rough AF (first AF) is performed based on image data for composition confirmation, thereby continuously focusing on an object to be photographed (a specific area such as a main subject or an attention area). Will fit. This eliminates the need for a conventional focus confirmation operation using a half shutter. In addition, a conventional so-called continuous AF effect can be realized with power saving. Further, the conventional switching process between continuous AF and single AF is not required.

  In addition, according to the first embodiment, by continuously performing rough AF (first AF) based on image data for composition confirmation, the object to be photographed (main subject) is gradually focused. become. For this reason, the angle of view also changes gradually, and the uncomfortable feeling given to the user can be suppressed.

Second Embodiment
Hereinafter, the second embodiment will be described in detail with reference to the drawings. The second embodiment is a modification of the first embodiment. Therefore, only the parts different from the first embodiment will be described, and the description of the same parts as the first embodiment will be omitted.

  In the second embodiment, a description will be given by taking as an example an apparatus including the lens barrel 10, the imaging device 20, and the storage medium 40 shown in FIG. 1 of the first embodiment.

  In the second embodiment, a configuration will be described in which after the imaging instruction in the second mode for generating recording image data, processing for confirming the focus state and correcting as necessary is performed.

  Hereinafter, the operation of the CPU 26 when the automatic detection mode is executed will be described with reference to the flowcharts of FIGS. 4 and 5.

  In step S201 to step S206, the CPU 26 performs the same processing as in step S101 to step S106 of the first embodiment.

  In step S207, the CPU 26 determines whether or not AF for the mask extracted by the mask extraction processing in step S203 (hereinafter referred to as “extraction mask”) is completed. The details of this AF will be described later in steps S208 to S210. If the CPU 26 determines that the AF has already been completed, the CPU 26 proceeds to step S211 described later. On the other hand, when determining that the AF has not been completed, the CPU 26 proceeds to step S208. The case where it is determined that the AF has not been completed is a case where a new extraction mask is extracted by the mask extraction processing in step S203. That is, when a new extraction mask is extracted, AF from step S208 to step S210 is executed, and when a new extraction mask is not extracted (the same extraction mask is extracted), AF from step S208 to step S210 is not executed. become.

  In step S208, the CPU 26 sets an area corresponding to the extraction mask extracted by the mask extraction process in step S203 as a main subject area. The CPU 26 may control the display unit 23 to display information on the set main subject area on the display unit 23. For example, the main subject area may be displayed so as to be visible by displaying a frame or the like in the set main subject area.

  In step S209, the CPU 26 sets the main subject area set in step S208 as a contrast evaluation target.

  In step S210, the CPU 26 executes AF on the extraction mask extracted by the mask extraction process in step S203. This AF is so-called normal AF (see FIG. 3A), and the CPU 26 controls the lens driving unit 12 via the lens barrel control unit 14 to move the AF lens 11 and contrast evaluation set in step S209. AF is executed based on the contrast evaluation value from the object.

  The CPU 26 determines the peak by AF, controls the lens driving unit 12 via the lens barrel control unit 14, moves the AF lens 11 to the peak, and ends the AF.

  In step S211, the CPU 26 records and updates mask information and focus information. The mask information is the same as that described in step S105 of the first embodiment. The focus information includes information regarding AF described in step S210.

  If it is determined in step S207 that AF has already been completed, it is considered that the same extraction mask has been extracted, and the CPU 26 informs the buffer memory unit 24, the storage unit 25, and the like as mask information and focus information. Record. On the other hand, if it is determined in step S207 that the AF has not been completed, it is considered that a new extraction mask has been extracted, and the CPU 26 notifies the buffer memory unit 24 and the storage unit of that fact and the new mask information and focus information. Record at 25 mag.

  In step S212, the CPU 26 determines whether or not the focus state is good. Whether or not the focus state is good can be determined with respect to the degree of change in mask information and focus information, front and rear focus information (front pin, rear pin, etc.), and the like. If the CPU 26 determines that the focus state is good, the CPU 26 proceeds to step S213. On the other hand, when determining that the focus state is not good, the CPU 26 proceeds to step S216 described later.

  In step S213, the CPU 26 determines whether or not a shooting instruction has been issued. If the CPU 26 determines that a shooting instruction has been given, the process proceeds to step S214. On the other hand, if it is determined that the shooting instruction is not issued even after a predetermined time has elapsed, the CPU 26 returns to step S202 described above, and performs the processing from step S202 onward for the next through image. The photographing instruction is performed by a user operation via the shutter button of the operation unit 27. This user operation may be a so-called half shutter or all shutter.

  In step S214, the CPU 26 executes AE and AWB based on the information on the main subject area set in step S208.

  In step S215, the CPU 26 determines whether or not a predetermined time has elapsed since the completion of AF performed in step S210. If the CPU 26 determines that a predetermined time has elapsed since the completion of AF, the CPU 26 proceeds to step S216. On the other hand, when determining that the predetermined time has not elapsed since the completion of AF, the CPU 26 proceeds to step S223 described later. The case where it is determined that a predetermined time has elapsed since the completion of AF is a case where it can be estimated that the main subject may have changed. In this case, the processing from step S216 to step S222 is executed in order to check the focus state and perform correction as necessary. On the other hand, the case where it is determined that a predetermined time has not elapsed since the completion of AF is a case where it can be considered that the main subject has not changed. In this case, the process proceeds to step S223 and photographing is performed.

  In step S216, the CPU 26 reads the final focus information from the buffer memory unit 24, the storage unit 25, and the like.

  In step S217, the CPU 26 determines whether or not the focused state is maintained. Whether or not the focus state is maintained depends on the comparison result between the state immediately after the AF performed in step S210 and the state of the final focus information read in step S216, the degree of change of the mask information and the focus information, and before and after. The focus information (front pin, rear pin, etc.) can be determined. When the CPU 26 determines that the focus state is maintained, the CPU 26 proceeds to step S223 described later. On the other hand, when determining that the focus state is not maintained, the CPU 26 proceeds to S218.

  In step S218, the CPU 26 calculates a focus shift. FIG. 6 is a diagram for explaining a focus shift. As shown in FIG. 6, the CPU 26 obtains the mask edge based on the mask information (E1 to E6 in FIG. 6), and can calculate the focus shift based on the change in the edge evaluation value. When the change in the edge evaluation value is greatly deteriorated, the focus shift is large, and when the change in the edge evaluation value is small, the focus shift is small or there is no focus shift.

  In step S219, the CPU 26 determines whether it is a front pin or a rear pin according to the focus shift calculated in step S218.

  In step S220, the CPU 26 sets the latest main subject area as a contrast evaluation target.

  In step S221, the CPU 26 controls the lens driving unit 12 via the lens barrel control unit 14 based on the determination result in step S219, and calculates the AF lens 11 in the front pin direction or the rear pin direction in step S218. It moves according to the out of focus.

  In step S222, the CPU 26 controls the lens driving unit 12 via the lens barrel control unit 14 to move the AF lens 11 and perform AF based on the contrast evaluation value from the contrast evaluation target set in step S220. Run. Note that AF may be executed with a limited focus range at this time. The focus range may be limited according to the focus shift calculated in step S218.

  In step S223, the CPU 26 performs shooting by controlling each unit. At this time, the CPU 26 determines various image processing conditions and the like in the image processing device 22 based on the main subject region set in step S208.

  In step S224, the CPU 26 records an image generated by imaging on the storage medium 40 via the communication unit 28, and ends the series of processes.

  As described above, according to the second embodiment, when a user instruction regarding execution of imaging in the second mode for generating recording image data is received, confirmation of the focus state and correction as necessary are performed. Therefore, even when the main subject changes, it is possible to achieve power saving while maintaining the accuracy of focus adjustment.

  According to the second embodiment, as a preparatory operation, the lens position is changed to a focus position based on distance measurement information. Therefore, by executing normal AF before a user instruction regarding execution of imaging in the second mode for generating recording image data, it is possible to further reduce the shooting time lag and ensure a photo opportunity.

  In the second embodiment, an example is shown in which the elapsed time from the completion of AF is confirmed after the shooting instruction (step S215 in FIG. 5). However, the same confirmation may be performed before the shooting instruction. For example, a process for confirming the elapsed time from the completion of AF is performed between step S212 and step S213 in FIG. 4, and when a predetermined time has elapsed, the process from step S216 to step S219 or the process from step S216 to step S222 is executed. It is good also as composition to do.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

  A part or all of the processes described in the above-described embodiments may be appropriately combined and executed.

  In each of the embodiments described above, a single specific region (for example, a main subject region or a region of interest) may be detected or a plurality of specific regions may be detected in the detection by the mask extraction process. When a plurality of specific areas are detected, it is preferable to devise display contents when displaying information on the specific areas on the display unit 23. For example, it is preferable to make the distinction possible by changing the color of the display frame, changing the thickness of the line, changing the density of the line, changing the type of line (solid line / dotted line), and the like.

  In each of the above-described embodiments, the AF has been described as an example of the preparation operation. However, the present invention can be applied to any processing such as shooting conditions and image processing on an image after shooting. For example, it can be applied to AE, AWB, scene analysis, image processing, and the like.

  In each of the above embodiments, an example in which a series of processing is performed based on a through image for composition confirmation has been described, but the present invention is not limited to this example. For example, the present invention can be similarly applied to a case where a live view image for composition confirmation generated in a single-lens reflex camera or the like is targeted.

  In each of the above embodiments, the contrast AF has been described as an example, but the present invention can be similarly applied to the phase difference AF. For example, phase difference information can be used instead of the lens position and front / rear focus information (front pin, rear pin, etc.).

  In each of the above embodiments, an example in which a series of processing is performed for all frames has been described. However, the present invention is not limited to this example. For example, a plurality of images generated intermittently in time may be targeted. Specifically, a plurality of images subjected to frame thinning as appropriate may be targeted. By performing such processing, the processing load can be reduced.

DESCRIPTION OF SYMBOLS 20 ... Imaging device, 21 ... Imaging part, 22 ... Image processing apparatus, 23 ... Display part, 26 ... CPU

Claims (10)

An imaging unit having a first mode for capturing a subject image and generating composition confirmation image data; and a second mode for capturing the subject image and generating recording image data;
A region detecting unit that calculates a feature amount of an image indicated by the composition confirmation image data and detects a specific region based on the feature amount;
A control unit that performs an imaging preparation operation based on information calculated from the specific area detected by the area detection unit before the imaging unit performs imaging in the second mode. An imaging device. The imaging device according to claim 1,
The control unit calculates distance measurement information from the composition confirmation image data of the specific area detected by the area detection unit. The imaging device according to claim 2,
The imaging unit captures the subject image incident via an optical system and generates the composition confirmation image data and the recording image data.
The control unit executes an operation including focusing control related to the optical system as the preparation operation. The imaging device according to claim 3.
The control unit performs an operation including a change of a lens position of the optical system as the focus control. The imaging apparatus according to claim 4,
A reception unit that receives a mode switching instruction for switching from the first mode to the second mode;
When receiving the mode switching instruction, the control unit changes the lens position to an in-focus position based on the distance measurement information in the second mode and performs imaging. The imaging apparatus according to claim 4,
A reception unit that receives a mode switching instruction for switching from the first mode to the second mode;
When the control unit changes the lens position to a position near the in-focus position based on the distance measurement information and receives the mode switching instruction as the preparation operation, the control unit does not change the lens position in the second mode. An image pickup apparatus that picks up an image or changes the lens position to the in-focus position in the second mode. The imaging apparatus according to claim 4,
A reception unit that receives a mode switching instruction for switching from the first mode to the second mode;
As the preparatory operation, the control unit performs first focusing control based on the ranging information and changes the lens position to the first focusing position, or performs first focusing control based on the ranging information. When the lens position is changed to a position in the vicinity of the first focus position and the mode switching instruction is received, a second accuracy higher than that in the first focus control is obtained in the vicinity of the current lens position.
An imaging apparatus, wherein focusing control is performed to change the lens position to a second focusing position. The imaging apparatus according to claim 4,
A reception unit that receives a mode switching instruction for switching from the first mode to the second mode;
As the preparatory operation, the control unit changes the lens position to a focus position based on the distance measurement information, and receives the mode switching instruction, performs imaging without changing the lens position in the second mode. An imaging device characterized in that it performs. In the imaging device according to any one of claims 5 to 8,
A storage unit for storing the ranging information obtained by the control unit;
The control unit continuously calculates the ranging information until receiving the mode switching instruction, and updates the ranging information by storing the calculated ranging information in the storage unit. An imaging apparatus characterized by the above. The imaging device according to claim 2,
The distance measurement information includes information indicating whether it is a front pin or a rear pin with respect to the in-focus position, and the distance measurement information is detected from wobbling or axial aberration in contrast AF, In the phase difference AF, this corresponds to phase difference information.

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