JP6577820B2 - Imaging apparatus, control method therefor, and program - Google Patents

Description

  The present invention relates to an imaging apparatus, a control method thereof, and a program.

  In recent years, an imaging element (image sensor) having a curved imaging surface is known. By curving the imaging surface, it is possible to receive light from an incident subject at an angle close to the imaging surface even at a position where the image height is high.

  In general, when a lens that increases the incident angle of a light ray on an imaging surface is used, a lens for correcting the influence of aberrations such as field curvature and shading may be used in combination. However, since a lens for correcting the influence of aberration can be omitted by curving the imaging surface, a small and high-performance lens can be provided.

  Patent Document 1 discloses a technique for changing the curvature of the imaging surface of an imaging element built in an imaging device based on lens information (for example, optical characteristics such as lens-specific aberration). Since the curvature of the image pickup surface of the image pickup element can be dynamically changed according to the change in the zoom position, it is possible to obtain a good image quality in which the influence of aberration or the like is reduced over the entire zoom position.

JP 2007-208775 A

  By the way, when a lens unit that is supposed to be used in combination with an imaging device that curves the imaging surface is combined with an imaging device having a flat imaging surface, for example, the influence of optical characteristics (for example, aberration) is adequately affected. It cannot be reduced, and the image quality of the surrounding image is lowered. In addition, when the lens unit is combined with an imaging element that curves the imaging surface, if the curvature of the imaging surface is different from the curvature assumed by the lens unit, the influence of aberration or the like cannot be reduced in the same manner. That is, when the variable range of the curvature of the imaging surface does not correspond to the optical characteristics (that is, aberration, etc.) of the lens unit, the image quality may deteriorate due to the influence of the optical characteristics of the lens unit.

  The present invention has been made in view of the above-mentioned problems of the prior art. That is, even when the variable range of the curvature of the imaging surface does not correspond to the optical characteristics of the lens unit, the imaging apparatus capable of reducing image quality degradation due to the influence of the optical characteristics and its control method As well as providing a program.

  In order to solve this problem, for example, an imaging apparatus of the present invention has the following configuration. In other words, the imaging device has an imaging element configured to be able to bend the imaging surface, and a control unit that controls imaging conditions of the imaging optical system. The control unit includes a variable range of curvature when the imaging surface is curved, a predetermined range Based on the curvature for correcting the optical characteristics of the photographing optical system under the photographing conditions, it is controlled whether or not the photographing conditions of the photographing optical system are set to predetermined photographing conditions.

  According to the present invention, even when the variable range of curvature of the imaging surface does not correspond to the optical characteristics of the lens unit, it is possible to reduce image quality degradation due to the influence of the optical characteristics.

1 is a block diagram showing a functional configuration example of a digital camera system according to an embodiment of the present invention. The figure which shows typically the circuit structure of the image pick-up element 200 which concerns on this embodiment. The figure explaining the structure of the imaging part 102 and the curvature control part 103 which concern on this embodiment. The figure which shows the relationship between the focal distance and the curvature of the imaging surface of an image pick-up element based on Embodiment 1. FIG. 6 is a flowchart illustrating a series of operations related to a focal length control process of a zoom lens according to the first embodiment. The figure which shows the relationship between the aperture value and the curvature of the imaging surface of an image pick-up element based on Embodiment 2. FIG.

(Embodiment 1)
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. In the following, an example in which the present invention is applied to an arbitrary digital camera capable of controlling the curvature of the imaging surface will be described as an example of the imaging apparatus. However, the present invention is not limited to a digital camera and can be applied to any electronic device that can control the curvature of the imaging surface. These electronic devices may include, for example, a mobile phone, a game machine, a tablet terminal, a personal computer, a clock-type or glasses-type information terminal, a monitoring device, an in-vehicle device, a medical device, and the like.

(Configuration of digital camera system)
FIG. 1 is a block diagram illustrating a functional configuration example of a digital camera system as an example of the present embodiment. One or more of the functional blocks shown in FIG. 1 may be realized by hardware such as an ASIC or a programmable logic array (PLA), or may be realized by a programmable processor such as a CPU or MPU executing software. May be. Further, it may be realized by a combination of software and hardware. Therefore, in the following description, even when different functional blocks are described as the operation subject, the same hardware can be realized as the subject.

  The digital camera system of this embodiment includes a digital camera 100 that is a camera body, a lens unit 150, and a recording medium 160. The lens unit 150 and the recording medium 160 are configured to be detachable from the digital camera 100.

  The shutter 101 of the digital camera 100 controls the exposure time for the imaging unit 102 according to the control of the control unit 110. The imaging unit 102 includes an imaging element 200 described later in FIG. The imaging device 200 is configured by, for example, a charge-coupled device (CCD) image sensor, a complementary metal oxide semiconductor (CMOS) image sensor, or the like. The imaging element 200 converts an optical image formed on the imaging surface by the lens group 151 of the lens unit 150 into an electrical signal. The imaging unit 102 includes an A / D conversion processing function, and converts an analog imaging signal imaged by the imaging element 200 into digital image data (hereinafter simply referred to as image data). The imaging device 200 is an imaging device that can bend the imaging surface into, for example, a three-dimensional concave curved surface, as will be described later, and dynamically control the curved shape of the imaging surface (that is, also referred to as the curvature of the imaging surface). It is configured to be possible. The curvature control unit 103 controls the curvature of the imaging surface of the imaging device 200 based on an instruction from the control unit 110. The configuration of the image sensor 200 and the curvature control unit 103 and the operation for controlling the curvature of the imaging surface of the image sensor 200 will be described later.

  The image processing unit 104 performs predetermined development processing and color conversion processing on the image data output from the imaging unit 102 or the image data supplied from the memory control unit 105 and also performs image correction processing such as distortion correction. Geometric conversion processing, pixel interpolation, resizing processing, and the like are performed. Further, the image processing unit 104 performs predetermined calculation processing on the image data, and performs TTL (through the lens) type AWB (auto white balance) processing based on the obtained calculation result. Further, the image processing unit 104 performs predetermined arithmetic processing on the image data and outputs the input information to the control unit 110 in order to generate input information for the control unit 110 to perform exposure control and distance measurement control.

  The memory 106 includes a volatile storage medium, and temporarily stores image data input via the image processing unit 104 or the memory control unit 105. The memory 106 has a sufficient storage capacity for storing a predetermined number of still image data and moving image data and audio data for a predetermined time. The memory 106 can also serve as an image display memory (so-called video memory).

  The D / A converter 107 converts the image display data stored in the memory 106 into an analog signal. The D / A conversion unit 107 outputs an image display signal converted into an analog signal to the display unit 108.

  The display unit 108 includes a display device such as an LCD, for example, and displays the analog signal output from the D / A conversion unit 107 on the screen of the display device. In the present embodiment, the image data output from the imaging unit 102 is sequentially input to the display unit 108 via the memory 106 and the D / A conversion unit 107 and displayed on the screen. In this case, the display unit 108 displays the image data captured by the imaging unit 102 in substantially real time and functions as a so-called electronic viewfinder.

  The recording medium I / F 109 includes an interface with the recording medium 160. The recording medium 160 includes a recording medium including a semiconductor memory such as a memory card and a magnetic disk such as a hard disk, and records a photographed image.

  The control unit 110 includes, for example, a CPU or MPU, and controls the entire digital camera 100 by developing and executing a program stored in the nonvolatile memory 112 in a work area of the system memory 113. Further, the control unit 110 performs exposure control and distance measurement control based on the result of the arithmetic processing by the image processing unit 104 described above. For example, the control unit 110 performs so-called TTL AE (automatic exposure) control and EF (flash automatic dimming) control as exposure control. In addition, as the distance measurement control, the control unit 110 further inputs an AF evaluation value from the AF evaluation value detection unit 111 and performs AF (autofocus) control. The control unit 110 also performs display control by controlling the memory 106, the D / A conversion unit 107, the display unit 108, and the like.

  The AF evaluation value detection unit 111 calculates an AF evaluation value from phase difference detection information detected by a so-called phase difference detection method, contrast information detected from digital image data, and the like, and controls information on the AF evaluation value Output to the unit 110.

  The nonvolatile memory 112 includes a storage medium that can be electrically erased and recorded, such as a flash memory. The system memory 113 includes, for example, a RAM, and expands constants and variables for operation of the control unit 110, a program read from the nonvolatile memory 112, and the like. The system timer 114 is a time measuring unit that measures the time used for various controls and the time of a built-in clock.

  The mode switch 115, the first shutter switch 117, the second shutter switch 118, the operation unit 119, and the power switch 120 are user interface operation devices for the user to input various operation instructions to the control unit 110.

  The mode selector switch 115 operates the operation mode of the control unit 110 (the operation mode of the digital camera 100) from a plurality of operation modes such as a live view display mode, a still image shooting mode, a moving image shooting mode, and a playback mode. Used when switching to mode. Examples of the still image shooting mode include an auto shooting mode, a manual mode, and a program AE mode. The control unit 110 switches the operation mode of the digital camera 100 in accordance with the switching of the mode switch 115 and switches to any one of the still image shooting modes. As for the moving image shooting mode, a plurality of types of modes may be included as in the still image shooting mode.

  The shutter button 116 includes a first shutter switch 117 and a second shutter switch 118. The first shutter switch 117 is turned on by a so-called half-press (shooting preparation instruction) operation of the shutter button 116, and generates a first shutter switch signal SW1. The control unit 110 performs operations such as AF (auto focus) control, AE (auto exposure) control, AWB (auto white balance) control, or EF (flash automatic dimming / emission) control according to the first shutter switch signal SW1. Start. The second shutter switch 118 is turned on by a so-called full press (shooting instruction) operation of the shutter button 116, and generates a second shutter switch signal SW2. In response to the second shutter switch signal SW2, the control unit 110 starts control of a series of shooting operations from imaging by the imaging unit 102 to writing of image data to the recording medium 160.

  The operation unit 119 includes operation buttons such as a menu button, up / down / left / right four-way buttons, and a set (SET) button. The operation unit 119 may include a controller wheel that can detect a rotation operation by the user. When a rotation operation is performed by the user, the controller wheel generates an electrical pulse signal according to the operation amount. The control unit 110 controls each unit of the digital camera 100 based on the pulse signal. Further, the control unit 110 can determine the angle at which the controller wheel is rotated, the number of rotations, and the like based on the pulse signal. The controller wheel may be any operation device that can detect a rotation operation. For example, the controller wheel may be a dial that rotates in response to a user's rotation operation to generate a pulse signal. . Further, the controller wheel itself may not be rotated, but may be a device that detects a rotation operation of a user's finger or the like that touches the controller wheel like a so-called touch sensor (so-called touch wheel). The buttons of the operation unit 119 may be various function icons displayed on the display unit 108, and may be various function buttons that are appropriately assigned to each scene and selected by a touch operation or the like. . The function buttons include, for example, a determination button, a return button, an end button, an image advance button, or an attribute change button for setting various camera parameters. For example, when a menu button included in the operation unit 119 is pressed, the control unit 110 causes the display unit 108 to display various settable menu screens. As a result, the user can make various settings intuitively using the menu screen displayed on the display unit 108, and the four-way buttons and the set buttons. The operation unit 119 can also input special effect settings for obtaining special effect images in various shooting scenes, for example.

  Further, the operation unit 119 includes, for example, an operation input for setting an aperture value (F value) and an operation input for setting a zoom position when the lens unit 150 is an electric zoom lens.

  The power supply control unit 121 includes a battery detection circuit, a DC-DC converter, a switch circuit that switches a block to be energized, and the like, and detects whether or not a battery is installed, the type of battery, and the remaining battery level. Further, the power supply control unit 121 controls the DC-DC converter based on the detection result and the instruction of the control unit 110, and supplies necessary voltages to each unit including the recording medium 160 for a necessary period.

  The power supply unit 122 includes a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a NiCd battery, a NiMH battery, or a Li battery, an AC adapter, and the like, and supplies power to each part of the digital camera 100 and the lens unit 150. To do.

  The main body side lens I / F 123 includes an interface for electrically connecting the digital camera 100 and the lens unit 150 and communicating between the digital camera 100 and the lens unit 150.

  The lens unit 150 includes a lens (also referred to as a photographing optical system) that can be attached to and detached from the digital camera 100. The lens unit 150 includes a lens group 151 including a focus, a zoom, a diaphragm mechanism, and the like. The lens unit 150 includes a lens control unit 152 that controls each unit of the lens group 151 and a lens I / F 153 that communicates with the main body side lens I / F 123 of the digital camera 100. Furthermore, the lens unit 150 includes a lens information storage unit 154 that stores lens information described later.

(Configuration of Image Sensor 200)
Next, a configuration example of the imaging element 200 in the imaging unit 102 in the present embodiment will be described with reference to FIG.

  The imaging device 200 includes a unit pixel 201, a signal line 208, a constant current source 209 that becomes a load of the amplification MOS amplifier 205, a control line 210, an output amplifier 211, a vertical scanning circuit 212, a readout circuit 213, and a horizontal scanning circuit 214.

  Among these, the unit pixel 201 includes a photodiode (PD) 202, a transfer switch 203, a floating diffusion (FD) 204, an amplification MOS amplifier 205 that functions as a source follower, a selection switch 206, and a reset switch 207. In FIG. 2, for simplification of the drawing, the unit pixels 201 are shown only in 4 rows × 4 columns, but actually, a great number of unit pixels 201 are two-dimensionally arranged.

  The PD 202 of the unit pixel 201 converts the received light into electric charges. The transfer switch 203 transfers the charge generated by the photoelectric conversion to the FD 204 according to the transfer pulse φTX. The FD 204 temporarily stores the transferred charge. The FD 204, the amplification MOS amplifier 205, and the constant current source 209 constitute a floating diffusion amplifier. The signal charge of the unit pixel 201 selected by the selection switch 206 according to the selection pulse φSEL is converted into a voltage and output to the readout circuit 213 through the signal line 208. The reset switch 207 operates according to the reset pulse φRES and removes the electric charge accumulated in the FD 204.

  The readout circuit 213 selects a signal to be output based on a drive signal supplied from the horizontal scanning circuit 214 via the control line 210. A signal output from the readout circuit 213 is output to the outside of the image sensor 200 via the output amplifier 211. Further, the vertical scanning circuit 212 selects the transfer switch 203, the selection switch 206, and the reset switch 207.

(Operation principle of curvature control)
Further, the principle of curvature control of the imaging surface in the imaging unit 102 will be described with reference to FIG. FIG. 3 is a cross-sectional view of the imaging unit 102 and the curvature control unit 103 connected to the imaging unit 102.

  The bending portion 302 is configured to be able to change the curvature of the imaging surface of the imaging device 200, and in particular, bends in the direction of the opening 305 so as to form a concave shape. The image sensor 200 is fixed to the pedestal 303 on the flat surface 304 of the pedestal 303.

  Further, the imaging unit 102 is configured to form an opening 305 that is a closed space by the pedestal 303, the imaging element 200 supported by the pedestal 303, and the bottom plate 306. More specifically, the imaging device 200 has an imaging region in which the above-described unit pixels 201 are two-dimensionally arranged in the central portion of the imaging device 200, and has peripheral circuits 209 to 215 in the peripheral portion. Yes. The central portion is curved, for example, in an arc shape on the opening 305 side to form a curved portion 302. The flat part at the periphery of the curved part 302 is fixed to the flat surface 304 of the pedestal 303 via an adhesive layer. The bottom plate 306 is joined to the suction unit 307 included in the curvature control unit 103.

  The suction unit 307 controls the pressure (negative pressure) in the opening 305 by controlling the suction of the gas or liquid filled in the closed opening 305 and controls the curvature of the bending portion 302.

(Overview of zoom lens focal length control process)
The purpose of controlling the curvature of the imaging surface of the imaging device 200 is to use optical characteristics corresponding to the focal length when using the lens unit 150 (that is, various optical aberrations such as distortion and lateral chromatic aberration, so-called peripheral dimming). This is to reduce the influence of the characteristic (peripheral light amount drop). In particular, when using a compact lens unit that does not include a correction lens and reduces the cost, the influence of the optical characteristics according to the focal length of the lens is reduced by controlling the curvature of the imaging surface of the image sensor. There is a need to.

  When the influence of the optical characteristics of the lens unit is reduced by controlling the curvature of the imaging surface, the variable range of the curvature of the imaging surface needs to correspond to the optical characteristics of the lens unit. For example, when the optical characteristics of the lens unit (that is, curvature aberration, etc.) are designed to fit the variable range of the curvature of the imaging surface, the curvature of the imaging surface can be achieved even with a low-cost and compact zoom lens. By the control, an image that is less influenced by optical characteristics can be obtained.

  However, when the variable range of the curvature of the imaging surface does not correspond to a part of the optical characteristics on the lens unit side (for example, aberration occurring at a predetermined focal length), the lens unit is set to the predetermined focal length. In some cases, the image quality deteriorates at the periphery of the image due to the influence of aberration or the like. Therefore, the use of the lens unit can be prohibited in order to prevent the combination of the lens unit and an image sensor that does not support a part of the optical characteristics of the lens unit. For example, depending on the shape of the mount portion, it is possible to prevent the lens unit and the digital camera from being physically mounted in a combination of a lens unit and an image sensor that can cause image quality degradation.

  On the other hand, even if it is a combination of the lens unit and the imaging device, for example, it can be used appropriately except for a predetermined focal length. Therefore, disabling these combinations at all impairs user convenience There is. Therefore, in the present embodiment, by restricting the use of a part of the photographing conditions of the lens unit 150, for example, a part of the focal length that can be used as a zoom lens, the lens unit can be used while the lens unit can be used. Reduce the effects of optical properties.

  Next, with reference to FIG. 4, an example will be described in which the lens unit L1 is combined with the lens unit I1 and the lens unit I2 having different variable ranges of the curvature of the imaging surface to limit the shooting conditions. FIG. 4 shows the relationship between the movable focal length of the lens unit L1 and the curvatures of the imaging device I1 and the imaging device I2 that can reduce the influence of optical characteristics at the focal length. The lens unit L1 and the image sensor I1 are designed to fit in advance. For this reason, the imaging device I1 controls the curvature of the imaging surface to the curvatures (R1 to R8) corresponding to all the focal lengths (FL1 to FL8) of the lens unit L1, and at all the focal lengths of the lens unit L1. The influence of optical characteristics can be reduced.

  On the other hand, in the imaging element I2, the variable range of the curvature of the imaging surface is limited to R3 to R6. For this reason, the influence of the optical characteristics at the corresponding focal lengths FL3 to FL6 can be reduced, but the influence of the optical characteristics at the focal lengths other than FL3 to FL6 cannot be corrected appropriately. Therefore, in the present embodiment, in the combination of the lens unit L1 and the image sensor I2, the movable range of the focal length is limited to the focal lengths FL3 to FL6.

  The lens unit 150 in the present embodiment, for example, optically or electrically reads a rotation amount when a user rotates a lens operation unit (not shown), and electrically changes the focal length according to the rotation amount. It has a power zoom mechanism. In the following description, a process for limiting the movable range of the focal length when the lens unit 150 having the power zoom mechanism is attached will be described.

(A series of operations related to zoom lens focal length control processing)
A series of operations related to the control process of the focal length of the zoom lens will be described with reference to FIG. This series of operations is started when the mode switch 115 is set to the still image shooting mode and the power switch 120 is pressed by the user. This is realized by the control unit 110 expanding and executing the program stored in the nonvolatile memory 112 in the work area of the system memory 113.

  In step S <b> 501, when the power switch 120 is pressed and activated by the user, the control unit 110 determines whether the lens unit 150 is attached. For example, the control unit 110 determines the mounting state based on an electrical connection state with the lens unit 150 and whether or not a response command is received by the lens unit 150. If the control unit 110 determines that the lens unit 150 is attached, the process proceeds to S502. On the other hand, if it is determined that the lens unit 150 is not attached, the process proceeds to S503.

  In S <b> 502, the control unit 110 reads lens information of the lens unit 150. For example, the control unit 110 receives lens information stored in the lens information storage unit 154 via the main body side lens I / F 123 and temporarily stores it in the memory 106. The lens information received from the lens unit 150 is, for example, information indicating the relationship between the focal length that can be taken by the lens unit 150 shown in FIG. 4 and the curvature of the image sensor for correcting the optical characteristics of the lens unit 150. Including.

  In S <b> 503, since it is determined in S <b> 501 that the lens is not attached, the control unit 110 reads default lens information stored in advance in the nonvolatile memory 112 and temporarily stores it in the memory 106.

  In step S <b> 504, the control unit 110 determines whether the focal length range of the lens unit 150 corresponds to the variable range of curvature of the image sensor 200. Specifically, first, the control unit 110 extracts curvature information of the image sensor corresponding to each focal length based on the lens information acquired in S502 or S503. Then, the focal length range (for example, FL1 to FL8) of the lens unit 150 and the curvature range (R1 to R8 or R3 to R6) of the image sensor 200 are compared, and the curvature corresponding to each focal length of the lens unit 150 is obtained. It is determined whether the curvature of the imaging surface corresponds. For example, when the image sensor 200 is the image sensor I1 shown in FIG. 4, the control unit 110 determines that the L1 focal lengths FL1 to FL8 are opposed to each other because the curvature is R1 to R8. On the other hand, for example, when the imaging device 200 is I2, for example, since there is no corresponding curvature in the focal length FL1, the control unit 110 determines that there is a range that does not correspond. If the controller 110 determines that the range of curvature of the imaging element 200 corresponds to the range of the focal length of the lens unit 150, the process proceeds to S506. If the controller 110 determines that there is a range that does not correspond, the process proceeds to S505.

  In step S <b> 505, the control unit 110 limits the zoom movable range to a curvature that can be handled by the image sensor 200. Various methods can be used to limit the zoom movable range. For example, the control unit 110 transmits to the lens control unit 152 information indicating the zoom movable range (for example, information indicating a bit corresponding to a zoomable focal length as 1 and other values as 0), and the lens. The control unit 152 limits the zoom movable range according to the received information. In this case, when the user performs a zoom operation on the lens unit 150, the lens control unit 152 refers to the received information and controls the zoom movable range only to the focal length included in the zoom movable range. Further, when limiting the zoom movable range, the control unit 110 may change the imaging surface to the focal length corresponding to the changed curvature while changing the curvature of the imaging surface to the maximum or minimum curvature of the variable range. . Other methods may be used as long as the zoom movable range of the lens unit 150 can be limited. For example, each time the lens unit 150 detects a user operation related to zoom, the corresponding focal length information (for example, FL1) is transmitted to the control unit 110, and the control unit 110 determines whether to limit the corresponding focal length. You may do it. Further, when the zoom movable range is limited, the control unit 110 may display a warning message indicating that the zoom movable range is outside the zoom movable range on the display unit 108.

  In step S506, the control unit 110 determines whether there is a release. For example, the control unit 110 determines whether there is a release depending on whether the second shutter switch 118 is operated by a user operation or the like. When determining that the release has not been performed, the control unit 110 returns the process to S504. On the other hand, when it is determined that the release has been performed, the control unit 110 advances the processing to S507.

  In step S <b> 507, the control unit 110 controls the shutter 101, the imaging unit 102, and the memory control unit 105 to perform a still image shooting process, and stores, for example, a RAW image in the memory 106. In step S <b> 508, the control unit 110 reads out the RAW image stored in the memory 106 by the memory control unit 105, performs development processing by the image processing unit 104, and stores the obtained YUV image in the memory 106.

  In step S509, the control unit 110 performs compression processing on the stored YUV image by the image processing unit 104, and records the compressed image on the recording medium 160. When the compressed image is recorded on the recording medium 160, the control unit 110 ends the series of processes.

  In the above-described embodiment, the lens information received from the lens unit 150 may include other information. For example, the lens information may include an identifier of the lens unit 150. In this case, for example, the digital camera 100 holds information indicating the relationship between the focal length range (for example, FL1 to FL8) and the curvature for each identifier of the lens unit, and the curvature of the image sensor 200 according to the received identifier ( For example, R3 to R6) may be extracted.

  In the above-described embodiment, the example using the power zoom capable of electrically controlling the movable range of the focal length has been described. However, the present invention can also be applied to a case where the focal length of the lens group 151 is changed by rotating the zoom ring by a user operation. In this case, the operating range of the zoom ring may be physically limited. Further, even when it is difficult to physically limit the operation range of the zoom ring, for example, when the zoom movable range is limited by using image processing together according to the set position of the zoom ring. Similar effects can be obtained. For example, according to the set position of the zoom ring, the central portion of the acquired image is automatically cut out, and pixel interpolation and enlargement are performed to restrict the angle of view so as not to be larger than a predetermined focal length. In this case, a warning message indicating that the zoom is out of the movable range may be displayed on the display unit 108. In this way, as in the case where the zoom movable range is limited, it is possible to suppress deterioration in image quality in the peripheral portion, and even when it is difficult to physically restrict the lens unit 150 side, the zoom movable range can be reduced. Can be limited.

  As described above, in the present embodiment, when the variable range of the curvature of the imaging surface does not correspond to a part of optical characteristics on the lens unit side (for example, aberration occurring at a predetermined focal length), this is handled. The setting of shooting conditions that cause no optical characteristics was restricted. That is, when the curvature for correcting the optical characteristics of the lens unit at a predetermined focal length is not included in the variable range of the curvature of the imaging surface, the setting of the predetermined focal length is limited, and the lens unit optical The influence of the characteristic was reduced. By doing so, even if the variable range of the curvature of the imaging surface does not correspond to the optical characteristics of the lens unit, it is possible to reduce image quality degradation due to the influence of the optical characteristics. .

(Embodiment 2)
Next, Embodiment 2 will be described. In the first embodiment, when the image sensor cannot be controlled to a predetermined curvature, the setting of the zoom range corresponding to the predetermined curvature is limited. The second embodiment is different from the first embodiment in that the setting of the aperture value corresponding to the predetermined curvature is limited when the imaging element cannot be controlled to the predetermined curvature. In the following description, the configuration of the camera system according to the present embodiment will be described as being the same as that of the first embodiment. About the same structure, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted and it demonstrates focusing on a different point.

  First, for simplicity of explanation, a case where a single focus lens designed in accordance with a predetermined curvature is combined with the digital camera 100 having the image sensor 200 as a lens unit 150 will be described as an example. As described above, when the correspondence between the optical characteristics of the lens unit 150 and the curvature of the imaging surface of the imaging device 200 is not achieved, for example, curvature of field and peripheral light reduction occur at a position where the image height is high. In such a case, in this embodiment, by controlling the diaphragm in the lens unit 150 and restricting the diaphragm value to a large value (the direction in which the diaphragm is squeezed), the effects of field curvature and peripheral light reduction are reduced.

  In FIG. 6, an imaging device I3 whose curvature of the imaging surface is R1 and an imaging device I4 whose curvature of the imaging surface is R2 are used in combination with a lens unit 150 designed in accordance with the curvature of the imaging device I3. This shows the restriction on the aperture value when doing this.

  In the imaging device I3 (that is, when the curvature is set to R1), the aperture value can be set in the entire range of aperture values (F2.0 to F16.0). On the other hand, in the imaging device I4 (that is, when the curvature is set to R2), the aperture value is limited to be set within the range of the aperture value with a small aberration (F4.0 or more). That is, even when using an imaging device set to a curvature different from the curvature assumed by the lens unit 150, by limiting the aperture value that can be set, the influence of aberrations and the like when the lens unit 150 is used. Can be reduced.

  In the example of FIG. 6, the case where two imaging elements having different curvatures are used has been described. However, the above-described restriction of the aperture value is also effective when an imaging element capable of controlling the curvature of the imaging surface is used. When the imaging element 200 is controlled to the above-described curvature R1 or R2, the setting of the aperture value corresponding to the curvature can be limited. In this case, the control unit 110 receives lens information from the lens unit 150 as in the focal length control process of the zoom lens according to the first embodiment. The lens information may be information indicating a relationship between, for example, an aperture value that can be taken by the lens unit 150 and the curvature of the image sensor for correcting the optical characteristics of the lens unit 150. Then, when the image sensor 200 is set to a predetermined curvature, the control unit 110 determines a selectable aperture value based on the lens information and limits the aperture value.

  It should be noted that the above-described restriction of the aperture value is different depending on whether the aperture value is subjected to automatic exposure processing in which the aperture value is determined by a program diagram, or when exposure control is performed by a user operation as in the manual exposure mode, for example. May be. For example, the control unit 110 sets the above-described aperture value when performing automatic exposure control, while selecting the aperture value in the manual exposure mode, the aperture value requested by the user can be selected without limitation. It may be. Further, when limiting the aperture value, for example, a warning message may be displayed on the display unit 108. By doing so, the user can use a special effect that intentionally blurs or darkens the periphery.

  Furthermore, in the above-described embodiment, the example in which the range for setting the focal length of the zoom lens and the range for setting the aperture value are individually limited has been described. However, these processes may be performed in combination. In this case, for example, when limiting the range for setting the aperture value, reduce the limit of the range for setting the focal length, while for limiting the range for setting the focal length, limit the range for setting the aperture value. Should be relaxed. Furthermore, it is not limited to the range in which the focal length and aperture value of the zoom lens are set, but by limiting the range of distance that can be photographed and the range of position fluctuations in the optical image stabilization function, The image quality may be improved.

  As described above, when the curvature for correcting the optical characteristics of the lens unit at the predetermined aperture value is not included in the variable range of the curvature of the imaging surface, the setting of the predetermined aperture value is limited, The influence of the optical characteristics of the lens unit was reduced. By doing so, even if the variable range of the curvature of the imaging surface does not correspond to the optical characteristics of the lens unit, it is possible to reduce image quality degradation due to the influence of the optical characteristics. .

(Other embodiments)
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

DESCRIPTION OF SYMBOLS 102 ... Imaging part, 103 ... Curvature control part, 110 ... Control part, 108 ... Display part, 151 ... Lens group, 200 ... Imaging element

Claims (12)

An imaging device configured to be able to bend the imaging surface;
Control means for controlling the photographing conditions of the photographing optical system,
The control means is based on a variable range of curvature when the imaging surface is curved and a curvature for correcting optical characteristics of the imaging optical system under a predetermined imaging condition. Control whether to set the predetermined shooting conditions,
An imaging device comprising: The control means includes
When the first curvature for correcting the optical characteristic of the photographing optical system under the first photographing condition is included in the variable range of the curvature of the imaging surface, the photographing condition of the photographing optical system is the first photographing condition. Control the shooting conditions of the shooting optical system to be shooting conditions,
When the first curvature is not included in the variable range of curvature of the imaging surface, the imaging condition of the imaging optical system is controlled so that the imaging condition of the imaging optical system does not become the first imaging condition.
The imaging apparatus according to claim 1. The photographing condition of the photographing optical system is a focal length in a zoomable photographing optical system,
The imaging apparatus according to claim 1 or 2, wherein The photographing condition of the photographing optical system is an aperture value in the photographing optical system.
The imaging apparatus according to claim 1 or 2, wherein Exposure control means for controlling an aperture value in the photographing optical system by automatic exposure control and exposure control by user operation;
The control means controls shooting conditions of the shooting optical system when the automatic exposure control is performed.
The imaging apparatus according to claim 4. The optical characteristics of the photographing optical system include optical aberrations including peripheral aberrations, distortions, field curvatures, or lateral chromatic aberrations.
The imaging apparatus according to any one of claims 1 to 5, wherein The control means acquires information indicating a curvature for correcting optical characteristics of the photographing optical system with respect to photographing conditions from the photographing optical system configured to be detachable, and a variable range of the curvature of the imaging surface Compare with
The image pickup apparatus according to claim 1, wherein the image pickup apparatus is an image pickup apparatus. When the control means controls the photographing conditions of the photographing optical system, the control means further comprises display means for displaying a message for the user.
The imaging apparatus according to claim 1, wherein Curvature control means for changing the curvature of the imaging surface of the image sensor;
The image pickup apparatus according to claim 1, wherein the image pickup apparatus is an image pickup apparatus. When the control unit does not set the predetermined imaging condition, the curvature control unit causes the curvature control unit to change the curvature of the imaging surface to the maximum or minimum of the variable range of the curvature of the imaging surface, and the imaging of the imaging optical system. Control the conditions to the shooting conditions corresponding to the changed curvature,
The imaging apparatus according to claim 9. A method for controlling an imaging apparatus having an imaging element configured to be able to bend an imaging surface,
The control means has a control step of controlling the photographing conditions of the photographing optical system,
In the control step, based on the variable range of curvature when the imaging surface is curved and the curvature for correcting the optical characteristics of the imaging optical system under predetermined imaging conditions, the imaging conditions of the imaging optical system Control whether to set the predetermined shooting conditions,
And a method of controlling the imaging apparatus.   The program for making a computer perform the process of the control method of the imaging device of Claim 11.

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