JP2014155042A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a fluctuation in the angle of view of an acquired image when obtaining a change in the amount of blurring of the background caused by a change in the focal distance.SOLUTION: A segmentation region (CF) based on output of an image pickup element is set in an original image, and an image in the segmentation region is cut out from the original image to acquire an image to be outputted. If an instruction for increasing the amount of blurring is received after an output angle of view is set, a zoom lens is moved toward a telescopic end to contract the depth of field and increase the amount of blurring of the background. At this time, the angle of view of the image to be outputted is maintained at a set output angle of view by increasing the size of the segmentation region relative to the original image. Conversely, if an instruction for reducing the amount of blurring is received, the zoom lens is moved toward a wide end to expand the depth of field to increase the amount of blurring of the background. At this time, the angle of view of the image to be outputted is maintained at a set output angle of view by reducing the size of the segmentation region relative to the original image.

Description

  The present invention relates to an imaging apparatus.

  In some cases, a moderate blur is required for a captured image acquired by the imaging apparatus. Generally, the amount of blur (degree of blur) in the background can be increased by reducing the aperture value (F value). However, particularly in a compact camera, a lens having a large open F value is often used, and there is a tendency that moderate blurring is difficult to occur. Considering this, it is possible to try to obtain a necessary amount of blur using optical zoom. If the focal length changes due to the optical zoom, the depth of field in shooting changes, and as a result, the amount of background blur can be changed.

  In addition, in an imaging apparatus that generates an output image through blurring processing, a technique for adjusting the blurring amount in accordance with the electronic zoom magnification has been proposed (see Patent Document 1 below).

JP 2012-160863 A

  In order to obtain the blur amount desired by the photographer, a blur amount adjustment function is required. The photographer usually adjusts the amount of blur after deciding the shooting composition. However, whenever the amount of blur depends on the change of the focal length (change of the optical zoom magnification), the amount of blur is changed. The shooting angle of view changes, and as a result, the angle of view of the acquired image changes. If the shooting angle of view changes with the change in the focal length for changing the blur amount, the photographer moves to take a picture with a desired composition (away from the shooting target or close to the shooting target). An editing process for cutting out an image having a desired composition from an acquired image after shooting is necessary. Such a need is a great burden on the photographer or editor.

  SUMMARY An advantage of some aspects of the invention is that it provides an imaging apparatus that can suppress fluctuations in the angle of view of an acquired image accompanying zoom lens movement.

  An imaging apparatus according to the present invention includes an optical system including a zoom lens for adjusting a focal length, and an imaging element that generates an image signal of an input image according to light incident through the optical system, An imaging unit that shoots an imaging target, an output image generation unit that generates an image in a clipping region set in the input image as an output image, and a variation in the angle of view of the input image that accompanies movement of the zoom lens On the other hand, a cutout area setting unit that sets the cutout area so as to suppress a change in the angle of view of the output image is provided.

  If the focal length changes due to the movement of the zoom lens, the depth of field changes and the amount of background blur changes. However, it is not preferable for the photographer (user) that the angle of view of the acquired image changes every time the amount of blur is changed. According to the above configuration, even when the angle of view changes in the input image due to the movement of the zoom lens, the clipping region is set so as to cancel the angle of view variation, and an output image in which the angle of view is suppressed is obtained. It is done. That is, it is possible to obtain a change in the amount of blur due to movement of the zoom lens in a state where the change in the angle of view of the acquired image (output image) is suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the imaging device which can suppress the view angle fluctuation | variation of the acquired image accompanying zoom lens movement.

It is a schematic block diagram of a digital camera according to an embodiment of the present invention. It is an internal block diagram of the imaging part of FIG. It is a functional block diagram of a digital camera involved in the background blur mode. It is a figure which shows the relationship between the effective pixel area | region of an image pick-up element, an original image, and a target output image. It is a block diagram of a part related to focus control in a digital camera. It is a figure which shows the relationship between the position of a zoom lens, an imaging | photography field angle, a focal distance, a depth of field, and a blur amount. It is a figure which shows the mode of the transition of an original image and a target output image in response to the change instruction | indication of a blur amount. 6 is an operation flowchart of the digital camera in the background blur mode according to the first embodiment of the present invention. It is a figure which shows the output view angle setting part provided in the digital camera. It is a figure which shows the mode of the transition of the display image in the 1st Example of this invention in the setting step of an output view angle. FIG. 10 is a diagram illustrating a relationship between a focus lens position and an AF evaluation value according to the second embodiment of the present invention. FIG. 10 is a diagram illustrating a relationship between a main subject (photographing target) and a depth of field according to the second embodiment of the present invention. It is a block diagram of the site | part involved in the process of 4th Example of this invention. It is a figure which shows the display content which concerns on 5th Example of this invention. FIG. 20 is a diagram illustrating a state in which a plurality of update positions are set in a movable range of the zoom lens according to the sixth embodiment of the present invention. FIG. 20 is a functional block diagram of a digital camera related to an operation in a background blur mode according to the seventh embodiment of the present invention.

  Hereinafter, an example of an embodiment of the present invention will be specifically described with reference to the drawings. In each of the drawings to be referred to, the same part is denoted by the same reference numeral, and redundant description regarding the same part is omitted in principle. In this specification, for simplification of description, a symbol or reference that refers to information, signal, physical quantity, state quantity, member, or the like is written to indicate information, signal, physical quantity, state quantity or Names of members and the like may be omitted or abbreviated.

  FIG. 1 is a configuration block diagram of a digital camera (imaging apparatus) 1 according to an embodiment of the present invention. A digital camera (hereinafter may be abbreviated as “camera”) 1 includes respective parts referred to by reference numerals 11 to 15.

  FIG. 2 is an internal configuration diagram of the imaging unit 11. The imaging unit 11 includes an imaging element 33, a driver 34, and an optical system 35. The image sensor 33 is a solid-state image sensor composed of a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) image sensor. The optical system 35 includes a plurality of lenses including a zoom lens 30 for adjusting the focal length f and a focus lens 31 for focusing, and a diaphragm 32 for adjusting the amount of light incident on the image sensor 33. The driver 34 is formed by a motor or the like, and moves the lenses 30 and 31 and changes the opening of the diaphragm 32 based on a drive control signal from the main processing unit 13. Light from the imaging region (light from the subject) is incident on the image sensor 33 via the optical system 35. The image sensor 33 generates and outputs an image signal corresponding to incident light by photoelectric conversion. That is, the imaging unit 11 generates and outputs an image signal of the shooting target by shooting the shooting target using the imaging element 33.

  The operation unit 12 is formed by a mechanical operation member such as a mechanical push button switch or a dial and / or a touch panel that can be provided on the display unit 14, and receives various instructions and operations from the photographer. The main processing unit 13 is formed by a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and follows various instructions and operations input to the operation unit 12 while in the camera 1. Centrally control the operation of each part. The display unit 14 is a display screen composed of a liquid crystal display panel or the like, and displays an arbitrary video under the control of the main processing unit 13. In the present embodiment, the display and the display image mean the display and display image of the display unit 14 unless otherwise specified. The recording medium 15 is a non-volatile recording medium formed by a semiconductor memory, a magnetic disk, or the like, and records arbitrary signals and data under the control of the main processing unit 13.

  The subjects that fall within the shooting area of the imaging unit 11 include a main subject that is a shooting target focused by the photographer and subjects other than the main subject. Subjects other than the main subject are also called non-main subjects. Non-main subjects may include a near subject having a shorter subject distance than the main subject and a far subject having a longer subject distance than the main subject. These are collectively referred to as the background subject or simply the background. Regarding a certain subject, the subject distance refers to the distance between the subject and the camera 1 in real space.

  The camera 1 can acquire an image in which the main subject is in focus and the background is blurred through photographing, and at this time, the background blur can be variously adjusted. Of the operation modes of the camera 1, an operation mode that realizes background blur adjustment is referred to as a background blur mode. Hereinafter, the operation of the camera 1 in the background blur mode will be described unless otherwise specified. FIG. 3 shows a functional block diagram of the camera 1 involved in adjusting the background blur. A view angle control unit 52 including a cutout unit (output image generation unit) 51, an optical zoom control unit 53, and a cutout region setting unit 54 is provided in the main processing unit 13. The instruction receiving unit 55 is provided in the operation unit 12.

  The clipping unit 51 generates a target output image (output image) from the original image (input image) based on the output image signal of the imaging unit 11 (that is, the output image signal of the imaging element 33). FIG. 4 shows the relationship between the effective pixel area of the image sensor 33, the original image, and the target output image. The original image is an image formed in the effective pixel area of the image sensor 33. More specifically, the original image is an image itself that forms an image on the entire effective pixel region of the image sensor 33. However, the original image may be a part of an image formed on the entire effective pixel region of the image sensor 33. The cutout unit 51 cuts out an image in the cutout region set in the original image, and generates the cutout image as a target output image. In FIG. 4, the shaded area corresponds to the cutout area. When the image size of the image in the cutout area is different from the prescribed image size required for the target output image, the cutout unit 51 performs resolution conversion (image size enlargement process or image size reduction process) for matching the image sizes. ) To the image in the cutout region, a target output image having a prescribed image size can be generated. The prescribed image size is, for example, an image size of an image to be recorded on the recording medium 15 (hereinafter referred to as a recording size). The cutout area is often a part of the image area of the original image, but can match the entire image area of the original image. The display unit 14 can display the target output image obtained from the cutout unit 51, and the recording medium 15 can record the image signal of the target output image obtained from the cutout unit 51.

  Since the original image is an image formed in the effective pixel area of the image sensor 33 and the target output image is an image cut out from the original image, each of the original image and the target output image is captured by the imaging unit 11. Have the same depth of field. That is, in an image formed in the effective pixel area of the image sensor 33, when only a subject within a certain subject distance range is in focus and other subjects are blurred, the subject distance range is It represents the depth of field of shooting in the unit 11 and also represents the depth of field of each of the original image and the target output image. Assuming that an arbitrary subject is a point light source, that a certain subject is in focus is that the size (diameter) of the subject image on the image sensor 33 is equal to or less than a predetermined allowable circle of confusion. Means that. Hereinafter, when simply referred to as depth of field, it refers to the depth of field of shooting in the imaging unit 11.

  When the original image is captured, the position of the focus lens 31 is controlled so that the main subject is in focus (that is, the main subject is positioned within the depth of field). For example, the main processing unit 13 can be provided with the main subject detection unit 61 and the focus control unit 62 shown in FIG. The main subject detection unit 61 uses a known method based on the output signal of the image sensor 33 or based on a main subject setting instruction input to the operation unit 12 by the photographer, from among subjects in the imaging area of the imaging unit 11. Is detected. The focus control unit 62 controls the position of the focus lens 31 based on an output signal of the image sensor 33 or based on a focus lens position designation instruction input by the photographer to the operation unit 12 so that the main subject is in focus.

  The depth of field varies depending on the focal length f and the like, and the focal length f changes in response to a change in the position of the zoom lens 30. On the other hand, if the position of the zoom lens 30 changes, the shooting angle of view of the imaging unit 11, that is, the angle of view of the original image changes. The angle of view of the original image is an amount representing the size of the area in the real space that is reflected in the original image as an angle. The same applies to the target output image (that is, an amount representing the size of the area in the real space that appears in the target output image as an angle is called the angle of view of the target output image). The shallower the depth of field, the greater the background blur on the original and target output images. An index representing the degree of blur in the background is called a background blur amount or simply a blur amount. Assuming that a certain background subject is a point light source, the amount of background blur is proportional to the size of the image formed on the image sensor 33 by the point light source as the background subject.

  FIG. 6 shows the relationship between the position of the zoom lens 30, the shooting field angle of the imaging unit 11 (hereinafter simply referred to as the shooting field angle), the focal length f, the depth of field, and the amount of blur. The movable range of the zoom lens 30 is a range from a predetermined wide end to a predetermined tele end. When the zoom lens 30 is positioned at the wide end, the shooting angle of view is the largest, the focal length f is the shortest, the depth of field is the deepest, and the amount of blur is the smallest. As the zoom lens 30 moves from the wide end toward the tele end, the field angle of view decreases, the focal length f increases, the depth of field decreases, and the amount of blur increases. Therefore, when the zoom lens 30 is located at the telephoto end, the shooting field angle is the smallest, the focal length f is the longest, the depth of field is the shallowest, and the amount of blur is the largest.

The instruction receiving unit 55 in FIG. 3 is formed of a mechanical type or a dial or button on a touch panel, and receives an input of an instruction V _BLUR that is a blur amount adjustment / setting instruction from the photographer. The instruction V _BLUR is an instruction for adjusting the blur amount (that is, an instruction for increasing or decreasing the blur amount) or an instruction for setting the blur amount (that is, an instruction for directly specifying the value of the blur amount). However, since the depth of field and the amount of blur are linked, the instruction V _BLUR is an instruction for adjusting the depth of field (that is, an increase or decrease in the depth of field). Instruction) or an instruction to set the depth of field (that is, an instruction to directly specify the depth of field).

The input content of the instruction V _BLUR is transmitted to the view angle control unit 52. The optical zoom control unit 53 moves the zoom lens 30 toward the light end or the tele end so that the amount of blur according to the instruction V _BLUR is obtained, thereby changing the depth of field (however, the instruction V _BLUR Depending on the situation, this movement may not be necessary). The movement of the zoom lens 30 according to the instruction V _BLUR is accompanied by fluctuations in the shooting angle of view and the original image angle. The cutout area is set and adjusted in conjunction with the movement of the zoom lens 30 so that the change in the angle of view of the target output image is suppressed with respect to the change in the angle To do.

A more specific description will be given with reference to FIG. Consider a case where original images 301, 302, and 303 are acquired from the imaging unit 11 at times t1, t2, and t3, respectively. In addition, after the original image 301 is acquired at time t1, an instruction V _BLUR for increasing the blur amount is input to the instruction receiving unit 55, and the shooting angle of view decreases in response to the input of the instruction V _BLUR. It is assumed that the original image 302 is acquired from the above. Further, it is assumed that an instruction V _BLUR for reducing the amount of blur is input to the instruction receiving unit 55, and the original image 303 is acquired after the shooting angle of view increases in response to the input of the instruction V _BLUR . In each original image shown in FIG. 7, the person OBJ _A represents the main subject, the object OBJ _B represents the background in the cutout area, and the broken line frame CF shows a cutout frame that is the outer frame of the cutout area.

When the angle of view of the original image (shooting angle of view) decreases with the movement of the zoom lens 30, the cutout area setting unit 54 cuts out the ratio of the cutout area that occupies the original image (that is, the cutout with respect to the entire size of the original image). On the contrary, when the angle of view of the original image (shooting angle of view) increases as the zoom lens 30 moves, the ratio of the cut-out area occupying the original image is decreased. Thereby, the setting unit 54 suppresses the change in the angle of view of the target output image with respect to the movement of the zoom lens 30, and preferably makes the angle of view of the target output image unchanged with respect to the movement of the zoom lens 30. In the example of FIG. 7, although the angle of view of the original image decreases between times t1 and t2, and the angle of view of the original image increases between times t2 and t3, the target output image is changed between times t1 and t3. The angle of view is kept constant. When the angle of view of the original image decreases as the focal length f increases, the depth of field decreases and the amount of blur increases, and when the angle of view of the original image increases as the focal length f decreases, As the depth of field increases, the amount of blur decreases (see FIG. 6). In Figure 7, the increased thickness of the contour of the object OBJ _B, represents a state of increased blur.

The photographer can adjust the amount of blur by changing the focal length f via the input of the instruction V _BLUR , and can mix desired blur in the acquired image (target output image). At this time, it is not preferable for the photographer that the angle of view of the acquired image fluctuates every time the amount of blur is changed. The camera 1 according to the present embodiment has a function of suppressing the view angle variation of the target output image with respect to the view angle variation (shooting view angle variation) of the original image accompanying the movement of the zoom lens 30. A desired blur amount adjustment effect by moving the zoom lens can be obtained in a state in which the angle of view variation of the acquired image (target output image) is suppressed.

  More detailed operation examples, configuration examples, application techniques, and the like of the above-described camera 1 will be described in a plurality of embodiments below. As long as there is no contradiction, any one of the following embodiments can be combined with any other embodiment.

<< First Example >>
A first embodiment will be described. With reference to FIG. 8, the operation procedure until one target output image is recorded on the recording medium 15 in the background blur mode will be described. First, in step S11, the camera 1 starts through display processing. The through display process refers to a process of sequentially acquiring original images from the imaging unit 11 at a predetermined frame rate and displaying each target output image based on each original image on the display unit 14 in a moving image format. However, until the output angle of view is set in step S12, sequentially obtained original images are displayed on the display unit 14 in the moving image format. The through display process is continuously executed until the operation of the background blur mode ends.

After starting the through display process, in step S12, an output field angle is set as the field angle of the target output image. Thereafter, when the zoom lens 30 moves, the cutout region setting unit 54 changes the size of the cutout region in conjunction with the movement so that the field angle of the target output image is maintained at the set output field angle. In other words the step S13 following the step S12, whether there is an input of an instruction V _BLUR is confirmed, and when the input instruction V _BLUR the movement of the zoom lens 30 in response to an instruction V _BLUR at step S14 At the same time, the size of the cutout area is changed. When the instruction V _BLUR is input, the process proceeds to step S14. When the instruction V _BLUR is not input, the process directly proceeds to step S15.

  In step S <b> 15, the main processing unit 13 confirms whether or not a predetermined shutter instruction is input to the operation unit 12. If no shutter instruction is input, the process returns to step S13. If a shutter instruction is input, the current target output image is recorded on the recording medium 15 in step S16. In other words, the original image is acquired from the image sensor 33 at the position of the zoom lens 30 and the size of the cut-out area at the time when the shutter instruction is input, and the target output image is generated from the acquired original image. Thus, the image signal of the target output image is recorded on the recording medium 15. When the image signal of the target output image is recorded on the recording medium 15 in response to the shutter instruction, the image signal of the original image may be recorded on the recording medium 15 in association with the image signal of the target output image.

  The setting of the output angle of view in step S12 is executed by an output angle of view setting unit 71 (see FIG. 9) provided in the main processing unit 13. The photographer inputs a predetermined selection instruction to the operation unit 12 so that the blur priority mode that prioritizes the maximization of the blur amount or the image that prioritizes setting the angle of view of the target output image to the desired angle of view. The corner priority mode can be selected as the background blur mode.

  When the blur priority mode is selected as the background blur mode, the output field angle setting unit 71 sets the field angle of the original image obtained when the focal length f is set to the maximum value within the variable range of the focal length f. Set as output angle of view. This makes it possible to maximize the amount of blur. After setting the output angle of view, the required size of the cutout area (ie, electronic zoom magnification) can be determined as one.

In the present embodiment, when the zoom lens 30 is disposed at the telephoto end, the focal length f is maximized (see FIG. 6). Therefore, specifically, for example, when the blur priority mode is selected as the background blur mode, in step S12, the setting unit 71 actually moves the zoom lens 30 to the tele end and arranges the zoom lens 30 at the tele end. The angle of view of the original image obtained in the state is set as the output angle of view. At this time, the original image itself is displayed as the target output image on the display unit 14, and the blur amount of the target output image at this time is the maximum (see FIG. 6). Therefore, the photographer can check the maximum amount of background blur. When it is desired to reduce the background blur, the photographer may input an instruction V _BLUR for requesting a reduction in the amount of blur.

Alternatively, for example, when the blur priority mode is selected as the background blur mode, in step S12, the setting unit 71 fixes the position of the zoom lens 30 regardless of whether the zoom lens 30 is currently positioned at the tele end. In this state, the angle of view of the original image that will be obtained when the zoom lens 30 is disposed at the telephoto end is set as the output angle of view, and the cutout area is set so that the angle of view of the target output image matches the output angle of view. Is given to the cutout region setting unit 54. In this method, the waiting time and the power consumption are reduced by the amount that the process of actually moving the zoom lens 30 to the telephoto end is not required at the output field angle setting stage. After step S12, the photographer can obtain an increase or decrease in the amount of blur through the input of the instruction V _BLUR as necessary, and the zoom lens 30 is moved in response to the instruction V _BLUR . Depending on the configuration of the optical system 35, the position of the zoom lens 30 when the focal length f is maximized may not coincide with the telephoto end.

  When the angle of view priority mode is selected as the background blur mode, the output angle of view setting unit 71 sets the output angle of view in accordance with a predetermined angle of view setting instruction input from the photographer. The operation unit 12 receives an input of an angle of view setting instruction. When the angle-of-view priority mode is selected as the background blur mode, first, the setting unit 71 displays the original image on which the output angle-of-view setting frame 330 is superimposed on the display unit 14 as shown in the display state 341 of FIG. In this state, input of an angle of view setting instruction to the operation unit 12 is awaited. In the drawings showing the display content of the display unit 14 including FIG. 10, the hatched area represents the housing of the display unit 14. The photographer can freely adjust the size of the output field angle setting frame 330 on the display unit 14 and the original image using the operation unit 12 (see the display state 342). When the size reaches a desired size, a determination instruction is input to the operation unit 12. Then, the setting unit 71 sets the angle of view in the output angle of view setting frame 330 at the time when the determination instruction is input as the output angle of view. After setting the output angle of view, a target output image having the same angle of view as the output angle of view is displayed on the display unit 14 by through display processing (see display state 343).

  In order to generate a target output image having the same angle of view as the output angle of view and display it on the display unit 14, the position adjustment of the zoom lens 30 or the size of the cutout area may be adjusted, or they may be used in combination. You may do it. However, when the angle of view larger than the shooting angle of view when the zoom lens 30 is disposed at the telephoto end is set as the output angle of view, the zoom lens 30 is set so that the angle of view does not become smaller than the output angle of view thereafter. It is necessary to limit the movement range (for example, if the horizontal shooting angle of view is set to 8 ° when the horizontal output angle of view is set to 10 °, a target output image having a horizontal angle of view of 10 ° is generated. Because you can't.) The restriction content of the movement range of the zoom lens 30 is obtained from the output field angle. In the view angle priority mode, it is possible to obtain a target output image having a view angle desired by the photographer. Even in the angle-of-view priority mode, after setting the output angle of view, the required size of the clipping region (ie, electronic zoom magnification) can be determined as one.

<< Second Example >>
A second embodiment will be described. The amount of blur can be increased by adjusting the position of the focus lens 31 so that the main subject (photographing target) exists in the vicinity of the end within the distance range belonging to the depth of field. For example, by disposing the focus lens 31 closer to the focus lens position, the background on the far side of the main subject can be further blurred. In order to realize this, the focus control unit 62 in FIG. 5 may perform the following operation.

  The focus control unit 62 extracts the luminance signal of the image area where the image signal of the main subject exists from the output signal of the image sensor 33, and the amount of a predetermined high-frequency component among the spatial frequency components of the extracted luminance signal is an AF evaluation value The calculation obtained as follows is performed. By performing this calculation every time the focus lens 31 is moved by a predetermined amount, the relationship between the AF evaluation value and the position of the focus lens 31 as shown in FIG. The position of the focus lens 31 that maximizes the AF evaluation value is referred to as a focus lens position. When the position of the focus lens 31 is arranged at the focus lens position, the blur of the image of the main subject on the image sensor 33 is minimized, but even if the position of the focus lens 31 is slightly deviated from the focus lens position, the main subject. The in-focus state is not lost (that is, when the main subject is regarded as a point light source, the diameter of the image of the main subject is maintained below the allowable circle of confusion on the image sensor 33).

  Here, for concrete explanation, when the position of the focus lens 31 is deviated from the focus lens position by ΔL in the closest direction, the main subject is positioned at the far end 361 within the depth of field (FIG. )), And when the position of the focus lens 31 is shifted by ΔL in the direction of infinity from the focus lens position, the main subject is located at the near end 362 within the depth of field (FIG. 12B). )reference). As the focus lens 31 moves in the closest direction, the subject distance of the subject in focus decreases, and as the focus lens 31 moves in the infinity direction, the subject distance of the subject in focus increases. The far end 361 and the near end 362 indicate the maximum value and the minimum value of the distance range belonging to the depth of field, respectively.

  When a predetermined far blur instruction is input to the operation unit 12 or when it is known that the non-main subject is a far side subject, the focus control unit 62 determines the position of the focus lens 31 as the focusing lens. It can be moved from the position in the closest direction by a predetermined amount not more than ΔL. As a result, as shown in FIG. 12A, the main subject is located within the depth of field and located on the infinity side from the center of the depth of field (that is, in a direction away from the camera 1 when viewed from the center). The main subject is located), and the blur amount of the far-side subject can be increased. Conversely, when a predetermined near-side blur instruction is input to the operation unit 12 or when it is known that the non-main subject is the near-side subject, the focus control unit 62 determines the position of the focus lens 31. Can be moved from the in-focus lens position by a predetermined amount not more than ΔL in the infinity direction. Accordingly, as shown in FIG. 12B, the main subject is located within the depth of field and closer to the center of the depth of field (that is, the main subject is closer to the camera 1 as viewed from the center). The subject is located), and the amount of blur of the closest subject can be increased.

  Although the method using the AF evaluation value has been described, the focus control unit 62 detects the subject distance of the main subject by a known method based on the output signal of the image sensor 33 or by using a distance measuring sensor (not shown). Deriving the far end 361 and the near end 362 of the depth of field based on the positions of the lenses 30 and 31, the opening of the diaphragm 32, and the characteristics of the optical system 35, and using these detection results and derivation results, The position of the focus lens 31 may be controlled so that the subject is located on the infinity side or the near side from the center of the depth of field.

<< Third Example >>
A third embodiment will be described. The output signal of the image sensor 33 is referred to as RAW data. The main processing unit 13 performs predetermined signal processing on the RAW data to generate a YUV signal, and further performs predetermined compression processing on the YUV signal to generate a compressed image signal. Then, the compressed image signal of the target output image can be recorded on the recording medium 15. The signal processing includes YUV conversion for converting RAW data into YUV signals, and further includes demosaicing processing, noise reduction processing, and the like. In the background blur mode, clipping is scheduled, and image signals outside the clipping region are not necessary for recording. Therefore, it is better to perform the cut-out process on the upstream side as much as possible to reduce the load of the post-process after the cut-out process. That is, the cutout unit 51 may perform cutout processing at the stage of RAW data (a target output image represented by RAW data may be generated from an original image represented by RAW data). Thereafter, the main processing unit 13 may perform the signal processing on the RAW data of the target output image, and further perform compression processing as necessary.

<< 4th Example >>
A fourth embodiment will be described. The super-resolution processing unit 81 and the main subject / background region setting unit 82 shown in FIG. 13 can be provided in the main processing unit 13 shown in FIG. The super-resolution processing unit 81 executes super-resolution processing for improving the resolution of the target output image based on the output signal of the image sensor 33 including the image signal of the target output image. For example, in super-resolution processing, the resolution of one or more target output images included in the plurality of target output images may be improved using image signals of the plurality of target output images acquired at a plurality of times. it can. When the predetermined recording size on the recording medium 15 is larger than the image size of the original image or the target output image, an enlargement process of the image size is necessary. In such a case, the super-resolution process is particularly useful. . By using the super-resolution processing, it is possible to suppress the degradation of resolution accompanying the enlargement of the image size. However, if high-resolution super-resolution processing is performed on the background image portion, background blur may be reduced more than necessary.

  Therefore, when performing the super-resolution processing on the target output image, the super-resolution processing unit 81 may make the super-resolution processing strength for the background region weaker than the super-resolution processing strength for the main subject region. As a result, the background blur is avoided from being reduced more than necessary while increasing the resolution of the main subject.

  The setting unit 82 in FIG. 13 includes the main subject detection unit 61 in FIG. 5, and detects a main subject from subjects in the imaging region of the imaging unit 11. Further, the setting unit 82 uses the contour extraction, region division, and the like based on the image signal of the original image or the target output image, and an image in which the image signal of the main subject exists in the entire image region of the target output image. An area (hereinafter referred to as a main subject area) and an image area (hereinafter referred to as a background area) where a background image signal exists are set. In other words, the entire image area of the target output image is classified into a main subject area and a background area. The super-resolution processing unit 81 uses the setting content of the setting unit 82 to weaken the super-resolution processing intensity for the background region than the super-resolution processing strength for the main subject region.

  If the intensity of the super-resolution process for the background area is weaker than the intensity of the super-resolution process for the main subject area, apply the super-resolution process only to the main subject area and do not apply the super-resolution process to the background area. Is also included. When conditions other than the super-resolution processing intensity are constant, the maximum spatial frequency that can be expressed in the attention area is improved if the super-resolution processing intensity for the attention area is increased. The intensity of the super-resolution process can be changed by changing the parameters that define the content of the super-resolution process, and a method known as a super-resolution process method and a method of changing the intensity of the super-resolution process (for example, The method described in JP2011-91618A or JP2010-278898A) can be used.

<< 5th Example >>
A fifth embodiment will be described. As described with reference to FIG. 8, after the output angle of view is set, the target output image having the output angle of view is displayed in the through display process. Difficult to grasp (shooting angle of view). In consideration of this, in the through display process, not only the target output image but also an original image having a shooting angle of view may be displayed. A display control unit (not shown) for controlling the display content on the display unit 14 is included in the main processing unit 13. When the display control unit displays an arbitrary image including the target output image or the original image, the display control unit appropriately performs resolution conversion in accordance with the display size of the image.

  The display unit 14 may simultaneously display the target output image and the original image in the through display process. For example, in the through display process, as shown in FIG. 14A, the display unit 14 displays the target output image using the entire screen and displays the original image superimposed on the target output image on the display unit 14. Good (the original image may be displayed in superimposition). In the example of FIG. 14A, a frame 401 is set in the target output image displayed on the display unit 14, the original image is displayed in the frame 401, and a frame 402 corresponding to the cutout area is also displayed in the frame 401. Has been. Instead of superimposing and displaying the original image, the target output image and the original image may be displayed side by side.

  The display unit 14 may display the target output image and the original image in a time division manner in the through display process. That is, for example, the display unit 14 may alternately display the target output image and the original image as shown in FIG. Switching of the display image is executed periodically with time or according to a switching instruction that can be input to the operation unit 12. When displaying the original image, it is preferable to display a frame 412 corresponding to the cutout region.

  The display unit 14 may further display the current focal length f in the through display process.

<< Sixth Example >>
A sixth embodiment will be described. Since the zoom lens 30 moves substantially seamlessly within the movable range, and the depth of field does not change much when the position of the zoom lens 30 changes slightly, the photographer cannot easily see the change in the amount of blur. . When the photographer instructs to increase or decrease the amount of blur, it is preferable for the photographer to confirm that the amount of blur actually increases or decreases in response to the instruction.

  Considering this, as shown in FIG. 15, it is preferable to set the first to m-th update positions that are points for updating the display image within the movable range of the zoom lens 30. An update position setting unit 91 for performing the setting is provided in the main processing unit 13 of FIG. The setting unit 91 may be a memory that simply holds each update position. The first update position coincides with the wide end, and the m-th update position coincides with the tele end. For any integer i, the i-th update position and the (i + 1) th update position are adjacent to each other, and the (i + 1) th update position is closer to the tele end than the i-th update position. Although it is possible to set m = 2, m is preferably an integer of 3 or more. Simply, the second to (m−1) th update positions may be set at the boundary positions of adjacent ranges when the movable range is equally divided into (m−1) ranges.

  During the through display process, the display unit 14 outputs the first target output when the zoom lens 30 is positioned at the i-th update position in the process of moving the zoom lens 30 toward the telephoto end. After the image is displayed, the display image is maintained as the first target output image until the zoom lens 30 reaches the (i + 1) th update position, and when the zoom lens 30 reaches the (i + 1) update position. The display image is updated to the second target output image. This makes it easier for the photographer to check the change in the amount of blur. The first and second target output images are target output images based on original images taken when the zoom lens 30 is positioned at the i-th and (i + 1) -th update positions, respectively. The same update process is performed in the process in which the zoom lens 30 is moving toward the wide end.

  The skilled photographer often recognizes how much the blur is changed by changing the F value. Therefore, the setting unit 91 may set each update position based on the F value. As a specific example, it is considered that the focal length f when the zoom lens 30 is positioned at the wide end is 35 mm in terms of 35 mm film, and the F value of the optical system 35 is fixed to 3.5. . In this case, the amount of blur is proportional to the lens effective aperture D of the optical system 35 and is “D = f / (F value)” (that is, the effective aperture D is obtained by dividing the focal length f by the F value). ). At this time, in order to obtain a blur amount corresponding to a state where the F value is 2.8, the zoom is performed to a position where the focus processing f is set to about 44 mm from “f / 3.5 = 35 / 2.8”. It can be seen that the lens 30 may be disposed. Therefore, the position of the zoom lens 30 at which the focus process f is about 44 mm is determined as the second update position. Then, in the process in which the zoom lens 30 moves from the first update position to the second update position, it is possible to confirm the change in the display image as if the F value changed from 3.5 to 2.8. Makes it easy to understand changes in the amount of blur. At this time, the F value (3.5 or 2.8) corresponding to the display image may be displayed on the display unit 14.

<< Seventh Embodiment >>
A seventh embodiment will be described. FIG. 16 is a functional block diagram of the camera 1 according to the seventh embodiment involved in the operation of the background blur mode. The function of each part referred to by reference numerals 111 to 115 is realized by the main processing unit 13.

The output angle-of-view acquisition unit 111 acquires an output angle of view desired by the photographer according to the instruction content input to the operation unit 12 and outputs output angle-of-view information. The blur amount information acquisition unit 112 acquires blur amount information indicating a blur amount according to the instruction V _BLUR . The angle of view control unit 113 includes setting units 116 and 117. The optical zoom control value setting unit 116 generates an optical zoom control value that designates a target value of the optical zoom magnification (that is, a target position of the zoom lens 30) based on the output field angle information and the blur amount information. The electronic zoom control value setting unit 117 generates an electronic zoom control value that designates the position and size of the cutout area based on the output field angle information, the blur amount information, and the optical zoom control value.

  The depth-of-field control unit 114 is a part that controls the depth of field through the adjustment of the opening of the diaphragm 32 or the position of the focus lens 31. The depth of field and the opening of the diaphragm 32 are controlled according to the blur amount information. A depth-of-field control value that specifies the position of the focus lens 31 is generated. The imaging processing unit 115 performs an exposure process for the image sensor 33 according to the optical zoom control value, the electronic zoom control value, and the depth of field control value, and generates a target output image through the clipping process.

  In each of the above explanations, it is assumed that the aperture of the diaphragm 32 is fixed (for example, assuming that the diaphragm 32 is fully opened), and the amount of blur and the field by adjusting the focal length f. Although the depth adjusting operation has been described, the opening degree of the diaphragm 32 can also be changed according to the blur amount information, thereby widening the range of adjustment of the blur amount. In addition, typically, the center of the cutout region matches the center of the original image, but the match is not essential. For example, the photographer can adjust the center position of the setting frame 330 during the adjustment of the setting frame 330 shown in FIG. 10, thereby making the center of the cutout region different from the center of the original image. be able to. When the center of the cut-out area does not coincide with the center of the original image, the position of the main subject on the target output image does not change before and after the change of the focal length f. The center position of the cutout region at is adjusted.

  The output field angle acquisition unit 111 functions as the output field angle setting unit 71 of FIG. The blur amount information acquisition unit 112 includes or is connected to the instruction receiving unit 55 (see FIG. 3). The view angle control unit 113 and the imaging processing unit 115 are formed by the imaging unit 11, the cutout unit 51, and the view angle control unit 52 of FIG. 3. Of the functions of the depth-of-field control unit 114, the function responsible for adjusting the position of the focus lens 31 includes the function of the focus control unit 62 of the second embodiment.

<< Deformation, etc. >>
The embodiment of the present invention can be appropriately modified in various ways within the scope of the technical idea shown in the claims. The above embodiment is merely an example of the embodiment of the present invention, and the meaning of the term of the present invention or each constituent element is not limited to that described in the above embodiment. The specific numerical values shown in the above description are merely examples, and as a matter of course, they can be changed to various numerical values.

  The target device that is the camera 1 or the main processing unit 13 can be configured by hardware such as an integrated circuit or a combination of hardware and software. Arbitrary specific functions that are all or part of the functions realized in the target device are described as a program, the program is stored in a flash memory that can be mounted on the target device, and the program is executed by the program execution device. The specific function may be realized by executing on a microcomputer (for example, a microcomputer that can be mounted on the target device). The program can be stored and fixed on an arbitrary recording medium. The recording medium for storing and fixing the program may be mounted or connected to a device (such as a server device) different from the target device.

DESCRIPTION OF SYMBOLS 1 Digital camera 11 Imaging part 12 Operation part 13 Main process part 14 Display part 15 Recording medium 51 Cutting part 52 Angle-of-view control part 53 Optical zoom control part 54 Cutting area setting part 55 Instruction reception part

Claims (8)

An optical system that includes a zoom lens for adjusting the focal length, and an imaging unit that captures an image of an imaging target, including an imaging element that generates an image signal of an input image corresponding to light incident through the optical system When,
An output image generation unit that generates an image in a cutout region set in the input image as an output image;
A clip region setting unit configured to set the clip region so that the angle of view variation of the output image is suppressed with respect to the angle of view variation of the input image due to the movement of the zoom lens. Imaging device. An instruction receiving unit that receives an input of a predetermined instruction;
An optical zoom control unit that changes a depth of field in shooting by the imaging unit by moving the zoom lens in response to an input of the predetermined instruction;
A display unit for displaying the output image,
The cutout region setting unit adjusts the size of the cutout region in conjunction with the movement of the zoom lens so that the angle of view variation of the output image is suppressed with respect to the movement of the zoom lens. The imaging apparatus according to claim 1. The cutout area setting unit increases the ratio of the cutout area that occupies the input image when the angle of view of the input image decreases with the movement of the zoom lens, and the movement of the zoom lens moves the The imaging apparatus according to claim 1, wherein the ratio is decreased when the angle of view of the input image is decreased. An output angle setting unit for setting an angle of view of the output image;
The output angle-of-view setting unit sets the angle of view of the input image obtained when the focal length is maximized, or sets the angle of view of the output image according to the input angle-of-view setting instruction. 4. The imaging apparatus according to claim 1, wherein an angle of view is set. The optical system further includes a focus lens for focusing,
The imaging apparatus further includes a focus control unit that controls the position of the focus lens,
The focus control unit is configured to control the focus lens so that the subject to be photographed is within the depth of field in photographing by the imaging unit and is located on the infinity side or the near side from the center of the depth of field. The image pickup apparatus according to claim 1, wherein the position is controlled. A super-resolution processor that performs super-resolution processing to improve the resolution of the output image;
An area setting unit that sets a first area in which the image signal to be captured exists in the entire image area of the output image and a second area other than the first area;
6. The super-resolution processing unit makes the intensity of the super-resolution processing for the second region weaker than the strength of the super-resolution processing for the first region. The imaging device described in 1. The imaging apparatus according to claim 1, further comprising a display unit that displays the input image and the output image simultaneously, or displays the input image and the output image in a time-sharing manner. A display unit for displaying the output image;
An update position setting unit that sets a plurality of update positions within a movable range of the zoom lens; and
The imaging apparatus according to claim 1, wherein the display unit updates a display image when the position of the zoom lens reaches each update position in the process of moving the zoom lens.

Images