JP7266204B2 - Imaging device - Google Patents

Description

The present disclosure relates to an imaging device having a tilt imaging function.
It relates to an imaging device.

Japanese Patent Application Laid-Open No. 2002-200001 discloses an image pickup apparatus having a tilt photographing function using the Scheimpflug principle.

JP 2017-173802 A

According to an image pickup device having a tilt shooting function using the Scheimpflug principle, for example, by tilting a lens, a game such as volleyball, soccer, track and field, or the like can be imaged from an obliquely upper position such as a stand seat in a stadium. In this case, an in-focus image can be captured from the near side to the far side of the floor surface (reference plane) of the stadium.

However, when the floor is focused on, the upper part of the player playing on the floor may not fit within the depth of field and the upper part may be blurred. In this case, by narrowing down the aperture of the optical system to deepen the depth of field, it is possible to generally focus on the upper side as well, but if the shutter speed cannot be changed, the ISO sensitivity should be adjusted by the amount of aperture. need to be increased, which increases the noise on the captured image.

The present disclosure provides an imaging device capable of obtaining an image in which a subject on a reference plane is in focus while suppressing an increase in ISO sensitivity.

An imaging device according to a first aspect of the present disclosure includes an imaging device that captures a subject image formed on an imaging surface and generates image data, and an optical system that includes a focus lens and forms a subject image on the imaging surface. a focus lens driving unit that drives the focus lens in the direction of the optical axis; an imaging element tilting unit that rotates and tilts the imaging surface of the imaging element about an axis that is not parallel to the optical axis; a focus lens driving unit and the imaging element tilting unit; and a control unit that controls the unit. The control unit (a) causes the focus lens driving unit to move the focus lens so that the subject is focused on a first predetermined position on the reference plane, and then (b) the height from the reference plane on the optical axis. Based on the positional relationship between the second predetermined position at the predetermined height and the first predetermined position, the focus lens driving unit is caused to move the focus lens so as to move the focus position from the first predetermined position to the second predetermined position. and (c) tilting the image pickup surface of the image pickup device by the image pickup device tilting unit so that the focus plane becomes a plane parallel to the reference plane and at a predetermined height.

An imaging device according to a second aspect of the present disclosure includes an imaging device that captures a subject image formed on an imaging surface and generates image data, and an optical system that includes a focus lens and forms an image of the subject on the imaging surface. , a focus lens driving unit that drives the focus lens in the optical axis direction, an optical system tilting unit that rotates and tilts the principal point plane of the optical system about an axis that is not parallel to the optical axis, a focus lens driving unit and the optical system a control unit that controls the tilting unit. The control unit (a) causes the focus lens driving unit to move the focus lens so that the subject is focused on a first predetermined position on the reference plane, and then (b) the height from the reference plane on the optical axis. Based on the positional relationship between the second predetermined position at the predetermined height and the first predetermined position, the focus lens driving unit is caused to move the focus lens so as to move the focus position from the first predetermined position to the second predetermined position. and (c) tilting the principal point plane of the optical system by the optical system tilting unit so that the focus plane becomes a plane parallel to the reference plane and at a predetermined height.

According to the imaging apparatus of the present disclosure, it is possible to obtain an image in which the subject on the reference plane is in focus while suppressing an increase in ISO sensitivity.

1 is a diagram showing the configuration of a digital camera according to Embodiment 1; FIG. The figure which showed an example of a structure of an image pick-up element tilting part. A diagram showing an example of the tilt shooting setting screen Flowchart explaining the flow of tilt shooting operation A diagram explaining a method of calculating the tilt angle φ0 of the imaging plane. Diagram explaining focusing within the depth of field A diagram explaining a method of calculating the optical axis direction distance t2. A diagram explaining a method of calculating a tilt angle φ1′ of an imaging plane. A diagram explaining how to calculate the aperture value F that achieves the depth of field set on the tilt shooting setting screen. FIG. 2 shows a configuration of a digital camera according to Embodiment 2; The figure which showed an example of a structure of an optical system tilting part. Flowchart explaining the flow of tilt shooting operation Diagram explaining how to calculate the tilt angle φ0 of the principal point plane A diagram explaining a method of calculating the optical axis direction distance t2. Diagram explaining how to calculate the tilt angle φ1 of the principal point plane A diagram explaining how to calculate the aperture value F that achieves the depth of field set on the tilt shooting setting screen. Diagram explaining the problem of the present disclosure Diagram explaining the problem of the present disclosure Diagram explaining the problem of the present disclosure

Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of well-known matters and redundant descriptions of substantially the same configurations may be omitted. This is to avoid unnecessary verbosity in the following description and to facilitate understanding by those skilled in the art. It is noted that the inventor(s) provide the accompanying drawings and the following description in order for those skilled in the art to fully understand the present disclosure, which are intended to limit the claimed subject matter. not something to do.

(Disclosure process)
17 to 19 are diagrams explaining the problem of the present disclosure. For example, when a game such as volleyball is to be imaged from an obliquely upper position such as a stand seat around a volleyball court (sports field), a general imaging device, for example, has a predetermined position on the floor as shown in FIG. When the position P1 (for example, the center line) is focused, the plane of focus is inclined with respect to the floor. As a result, the portion protruding from the range of depth of field in front of and behind the focus plane is out of focus and blurred. In such a case, by narrowing down the aperture greatly to increase the depth of field, it is possible to focus almost from the front to the back of the floor surface of the stadium. However, if the aperture is narrowed down, depending on the shooting conditions, it may be necessary to increase the ISO sensitivity (gain), resulting in an increase in image noise.

If an image pickup apparatus such as that disclosed in Patent Document 1 is used, according to the Scheimpflug principle, as shown in FIG. By tilting the plane containing the "lens principal point"), it is possible to focus from the front to the back of the stadium floor (an example of the reference plane) without stopping the diaphragm. It should be noted that focusing can be similarly achieved by tilting the imaging surface (sensor surface) of the imaging element.

However, when the floor is focused on, as shown in FIG. 18, only the upper (front) part of the depth of field can be used. ) may not fit within the depth of field and the top may be blurred. In this case, by narrowing down the aperture of the optical system to deepen the depth of field, it is possible to bring the upper part into focus, but if the shutter speed cannot be changed, raise the ISO sensitivity by the amount of the aperture. is necessary and increases noise on the captured image.

As a result of intensive studies by the inventors of the present application on the above problem, as shown in FIG. can also be effectively used, and it has been found that the above problems can be solved.

However, in order to achieve this, a new problem arises as to how to set the focal plane at a height above the floor where no object exists. This disclosure also solves this problem.

(Embodiment 1)
Embodiments of an imaging device according to the present disclosure will be described below with reference to the drawings.

1-1. Configuration FIG. 1 is a block diagram showing the configuration of a digital camera 100 according to the first embodiment.

The digital camera 100 includes an optical system 110, an image sensor 130, a liquid crystal monitor 220, a controller 180, a card slot 190, and the like.

Optical system 110 includes zoom lens 111 , focus lens 112 , and diaphragm 113 .

The zoom lens 111 is a lens for changing the magnification of the subject image formed on the imaging device 130 by the optical system 110 . The zoom lens 111 is composed of one or more lenses. The zoom lens driving unit 121 includes a user-operable zoom ring or the like, transmits the user's operation to the zoom lens 111 , and moves the zoom lens 111 along the optical axis direction of the optical system 110 .

The focus lens 112 is a lens for changing the focus state of the subject image formed on the imaging device 130 by the optical system 110 . The focus lens 112 is composed of one or more lenses.

The focus lens driver 122 includes a motor, and moves the focus lens 112 along the optical axis of the optical system 110 under the control of the controller 180 . The focus lens driving unit 122 can be implemented with a DC motor, stepping motor, servo motor, ultrasonic motor, or the like.

The diaphragm 113 is an element that adjusts the amount of light incident on the imaging element 130 . The diaphragm 113 has, for example, a plurality of diaphragm blades, and adjusts the amount of light incident on the imaging element 130 by adjusting the size of the opening formed by the diaphragm blades.

A diaphragm driver 123 drives the diaphragm 113 . Aperture driving unit 123 can be realized by a DC motor, a stepping motor, a servo motor, an ultrasonic motor, or the like.

The imaging device 130 captures a subject image incident through the optical system 110 and generates image data. The generated image data is digitized by an AD converter (Analog-to-Digital Converter (ADC)) 140 . The imaging device 130 operates at timing controlled by a timing generator (Timing Generator (TG)) 150 . The operation of the imaging device 130 includes a still image imaging operation, a through image imaging operation, and the like. The through image is mainly a moving image, and is displayed on the liquid crystal monitor 220 so that the user can decide the composition for capturing a still image.

The imaging element 130 is a CMOS (Complementary Metal Oxide Semiconductor) image sensor, a CCD (Charge Coupled Device) image sensor, or the like.

The liquid crystal monitor 220 displays an image indicated by display image data image-processed by the controller 180 . The liquid crystal monitor 220 has a touch sensor function. Various settings for the digital camera 100 can be made by the user performing a touch operation on the operation screen displayed on the liquid crystal monitor 220 .

The controller 180 controls the overall operation of the digital camera 100 by controlling components such as the imaging element 130 in response to instructions from the release button 210 . Controller 180 sends a vertical synchronization signal to timing generator 150 . In parallel with this, the controller 180 generates an exposure synchronization signal. Controller 180 uses built-in memory 230 (including DRAM (Dynamic Random Access Memory)) as a work memory during control operations or image processing operations. The controller 180 performs predetermined image processing on the image data digitized by the AD converter 140 . The predetermined image processing is, for example, gamma correction processing, white balance correction processing, scratch correction processing, YC conversion processing, electronic zoom processing, or JPEG (Joint Photographic Experts Group) compression processing.

The controller 180 may be configured by a hardwired electronic circuit, or may be configured by a microcomputer using a program. For example, the controller 180 can be configured with a CPU (Central Processing Unit), FPGA (Field-Programmable Gate Array), ASIC (Application Specific Integrated Circuit), or DSP (Digital Signal Processor).

A memory card 200 can be inserted into the card slot 190 . Card slot 190 controls memory card 200 based on control from controller 180 . The digital camera 100 can store image data in the memory card 200 and read image data from the memory card 200 .

Digital camera 100 of the present embodiment further includes image sensor tilting section 160 and tilt angle sensor 170 .

FIG. 2 is a diagram showing an example of the configuration of the imaging device tilting section 160. As shown in FIG. Note that FIG. 2 shows a lens 110A in which a plurality of lenses such as the zoom lens 111 and the focus lens 112 included in the optical system 110 are integrated into one.

The imaging element tilting unit 160 rotates and tilts the imaging surface (sensor surface) of the imaging element 130 around the x-axis (an axis perpendicular to the optical axis and on the imaging surface (an example of an axis not parallel to the optical axis)). Let In the example of FIG. 2, the image pickup device tilting unit 160 includes a movable plate 163 to which the image pickup device 130 is fixed, and a fixed frame 161 that is arranged in front of and behind the movable plate 163 and fixed to a housing member of the digital camera 100 or the like. , 162 . Coils 168 and 169 are fixed to the movable plate 163 , and magnets 164 , 165 , 166 and 167 are fixed to the fixed frames 161 and 162 at positions facing the coils 168 and 169 . Although not shown in FIG. 2, the tilt angle sensor 170 described above is attached to the movable plate 163 . By controlling the current applied to the coils 168, 169, the attractive force and the repulsive force between the coils 168, 169 and the magnets 164, 165, 166, 167 are changed to move the movable plate 163 around the x-axis. It can be rotated and tilted with respect to fixed frames 161 and 162 . As a result, the imaging surface of the imaging element 130 can be rotated and tilted around the x-axis. Note that the imaging device tilting unit 160 may be configured in any way as long as it is possible to rotate and tilt the imaging surface of the imaging device 130 about an axis that is not parallel to the optical axis. For example, the imaging element tilting unit 160 may use a stepping motor, a voice coil motor, or other actuators. When a stepping motor is used as the actuator, open control becomes possible, and along with this, the tilt angle sensor 170 can be made unnecessary.

The tilt angle sensor 170 is a sensor for detecting the tilt angle of the imaging surface of the imaging device 130 . The tilt angle sensor 170 can be implemented by, for example, a magnet and a Hall element.

The controller 180 uses the touch sensor function of the LCD monitor 220 to set the camera height, camera depression angle, focal plane height, and depth of field information set by the user, and based on the signal from the tilt angle sensor 170. to control the image sensor tilting unit 160 .

1-2. Operation The digital camera 100 of the present embodiment has a tilt photographing function of tilting the imaging surface of the imaging device 130 to capture an image. The tilt photographing function will be described below. Here, for ease of understanding, as a specific example, a case in which the digital camera 100 is installed above the stands of a stadium for volleyball, soccer, or the like and photographed is described.

FIG. 3 is a diagram showing an example of a tilt shooting setting screen.

Before using the tilt shooting function, the user uses the touch sensor function of the liquid crystal monitor 220 to display the tilt shooting setting screen (GUI) of FIG. The tilt shooting setting screen displays input windows for camera height, camera depression angle, focus plane height, and depth of field, and an execution button. The user inputs the camera height, camera depression angle, focus plane height, and depth of field, and touches the execution button. Note that the height of the focal plane and the depth of field are set to values desired by the user. When the execution button is touched, the controller 180 stores the input information (tilt shooting setting information) in the built-in memory 230 . Here, the camera height is the height from the stadium floor (an example of a reference plane) to the principal point of the optical system 110 (hereinafter referred to as "lens principal point"). In Embodiment 2, which will be described later, the camera height is the height from the floor surface of the stadium to the center of the imaging surface of the imaging device 130 . The camera depression angle is the angle between the optical axis of the optical system 110 and the horizontal direction when the optical system 110 of the camera is aimed at a first predetermined position (such as the center line) of the stadium. The focus plane height is the height from the floor of the stadium to the focus plane. The depth of field is the depth of field in the direction (vertical direction) perpendicular to the floor surface of the stadium.

FIG. 4 is a flow chart explaining the flow of the tilt photographing operation.

When the tilt shooting function is activated, the controller 180 reads the tilt shooting setting information set on the tilt shooting setting screen of FIG. 3 from the built-in memory 230 (S11).

The controller 180 calculates a tilt angle φ0 of the imaging plane for making the plane of focus perpendicular to the floor and including the first predetermined position P1 (S12).

FIG. 5 is a diagram explaining a method of calculating the tilt angle φ0 of the imaging plane. According to the Scheimpflug principle, in order to make the focal plane a plane perpendicular to the floor surface and containing the first predetermined position P1, on the vertical focal plane, an extension line of the imaging plane and an extension line of the principal point plane are They should intersect at one point. In this embodiment, by tilting the imaging plane from the state indicated by the dashed line parallel to the principal point plane to the state indicated by the solid line, the extension line of the imaging plane is aligned with the intersection of the extension line of the principal point plane and the focus plane. let them cross The tilt angle φ0 of the imaging plane at this time is equal to the included angle (φ0) around the intersection of the extension line of the imaging plane and the extension line of the principal point plane.

The tilt angle φ0 can be calculated by Equation (1).

ここで、ｆは光学系１１０の焦点距離、θはデジタルカメラ１００の俯角（カメラ俯角）、Ｈｃは床面から光学系１１０のレンズ主点までの距離（カメラ高さ）である。ｆの値は、内蔵メモリ２３０に予め格納されている。θとしては、チルト撮影設定画面で設定されたカメラ俯角が用いられる。Ｈｃとしては、チルト撮影設定画面で設定されたカメラ高さが用いられる。

Here, f is the focal length of the optical system 110, θ is the depression angle of the digital camera 100 (camera depression angle), and Hc is the distance from the floor to the lens principal point of the optical system 110 (camera height). The value of f is prestored in the built-in memory 230 . As θ, the camera depression angle set on the tilt shooting setting screen is used. As Hc, the camera height set on the tilt shooting setting screen is used.

The controller 180 tilts the imaging element 130 by the imaging element tilting section 160 so that the tilt angle of the imaging plane becomes φ0 (S13). This makes the plane of focus perpendicular to the floor.

Here, in AF control based on contrast detection, the position where the contrast value is maximized is the focus position (focus position), but within the depth of field, the detected contrast value is the same or almost the same value. As a result, as illustrated in FIG. 6, even if the first predetermined position P1 (for example, the center line) on the floor is not completely in focus (out of focus), The controller may determine that Therefore, in the present embodiment, the image pickup device 130 is tilted by the image pickup device tilting unit 160 so that the tilt angle of the image pickup surface becomes φ0, and the focal plane is made perpendicular to the floor surface. Shallow depth of field for directions. This improves the accuracy of focusing on the first predetermined position P1 on the floor.

The controller 180 causes the focus lens driving section 122 to move the focus lens 112 so that the contrast value of the image output from the image sensor 130 is maximized (S14). That is, the controller 180 performs autofocus control for focusing on the first predetermined position P1.

In moving the focus lens 112 in step S14, if the diaphragm 113 is not in the open state, the focus lens 112 may be moved after driving the diaphragm 113 so as to open the diaphragm. After moving the focus lens 112, the aperture is returned to the original aperture value (aperture value to be used at the time of photographing) from full aperture. By opening the diaphragm 113 when performing autofocus control in this manner, the depth of field becomes shallower, and the accuracy of focusing on the first predetermined position P1 on the floor can be further improved. can. It should be noted that changing the aperture value closer to full aperture than the original aperture value also makes the depth of field shallower, and it is possible to further improve the focusing accuracy. Here, when changing the aperture value to the open aperture side makes the image too bright, the shutter speed should be increased and/or the ISO sensitivity should be lowered.

The controller 180 moves the focus position from the first predetermined position P1 to the second predetermined position P2 having a height H (focus plane height) from the floor on the optical axis. to the lens principal point (hereinafter referred to as "optical axis direction distance") t2 is calculated (S15).

FIG. 7 is a diagram explaining a method of calculating the optical axis direction distance t2. FIG. 7(a) shows the image before the focus position is moved, and FIG. 7(b) shows the image after the focus position is moved.

The optical axis direction distance t2 can be calculated by Equation 2.

ここで、ｆは光学系１１０の焦点距離、θはデジタルカメラ１００の俯角（カメラ俯角）、ｔ１は、ステップＳ１４のオートフォーカス制御でフォーカスレンズ１１２が移動した後(コントローラが合焦していると判断したとき)の撮像面中心からレンズ主点までの光軸方向距離、Ｈはピント面の床面からの距離（ピント面高さ）である。ｆの値は、内蔵メモリ２３０に予め格納されている。θとしては、チルト撮影設定画面で設定されたカメラ俯角が用いられる。Ｈとしては、チルト撮影設定画面で設定されたピント面高さが用いられる。

Here, f is the focal length of the optical system 110, θ is the depression angle of the digital camera 100 (camera depression angle), and t1 is after the focus lens 112 has been moved by the autofocus control in step S14 (when the controller is in focus). is the distance in the optical axis direction from the center of the imaging plane to the lens principal point, and H is the distance of the focus plane from the floor surface (focus plane height). The value of f is prestored in the built-in memory 230 . As θ, the camera depression angle set on the tilt shooting setting screen is used. As H, the focus plane height set on the tilt shooting setting screen is used.

Note that the optical axis direction distance t1 used in Equation 2 can be obtained by the following method. Specifically, the digital camera 100 detects the position of the focus lens 112 in the optical axis direction based on a sensor, a focus motor control amount, or the like. The built-in memory 230 stores information on the optical axis direction distance from the imaging plane center to the lens principal point in association with the optical axis direction position. These can be stored, for example, in a table. The controller 180 detects the optical axis direction position of the focus lens 112 when focused on the first predetermined position P1, and based on the detected optical axis direction position, the optical axis direction from the imaging surface center to the lens principal point. The distance is read from internal memory 230 . Then, the controller 180 uses the read optical axis direction distance as the optical axis direction distance t1 in Equation (2).

The controller 180 causes the focus lens driver 122 to move the focus lens 112 so that the distance in the optical axis direction from the center of the imaging plane to the lens principal point is t2 (S16). For example, the optical axis direction position corresponding to the optical axis direction distance t2 is obtained with reference to the table, and the focus lens 112 is moved to the obtained position. As a result, the focus position is moved from the first predetermined position P1 to the second predetermined position P2 based on the positional relationship between the second predetermined position P2 and the first predetermined position P1.

The controller 180 calculates the tilt angle φ1 of the imaging plane for making the plane of focus parallel to the floor and at the height H (height of the plane of focus) (S17).

FIG. 8 is a diagram explaining a method of calculating the tilt angle φ1 of the imaging plane. According to the Scheimpflug principle, in order to make the focal plane parallel to the floor and at a height H (height of the focal plane), on the focal plane at this height H (height of the focal plane) , the extension line of the imaging plane and the extension line of the principal point plane should intersect at one point. In this embodiment, by tilting the imaging plane from the state indicated by the dashed line parallel to the principal point plane to the state indicated by the solid line, the extension line of the imaging plane is aligned with the intersection of the extension line of the principal point plane and the focus plane. let them cross The tilt angle φ1 of the imaging plane at this time is equal to the included angle (φ1) around the intersection of the extension line of the imaging plane and the extension line of the principal point plane.

The tilt angle φ1 can be calculated by Equation (3).

ここで、ｆは光学系１１０の焦点距離、θはデジタルカメラ１００の俯角（カメラ俯角）、Ｈｃは床面から光学系１１０のレンズ主点までの距離（カメラ高さ）、Ｈはピント面の床面からの距離（ピント面高さ）である。ｆの値は、内蔵メモリ２３０に予め格納されている。θとしては、チルト撮影設定画面で設定されたカメラ俯角が用いられる。Ｈｃとしては、チルト撮影設定画面で設定されたカメラ高さが用いられる。Ｈとしては、チルト撮影設定画面で設定されたピント面高さが用いられる。

Here, f is the focal length of the optical system 110, θ is the depression angle of the digital camera 100 (camera depression angle), Hc is the distance from the floor to the lens principal point of the optical system 110 (camera height), and H is the focal plane. This is the distance from the floor (focus plane height). The value of f is prestored in the built-in memory 230 . As θ, the camera depression angle set on the tilt shooting setting screen is used. As Hc, the camera height set on the tilt shooting setting screen is used. As H, the focus plane height set on the tilt shooting setting screen is used.

The controller 180 tilts the imaging element 130 by the imaging element tilting section 160 so that the tilt angle of the imaging surface becomes φ1 (S18). As a result, as shown in FIG. 8, the plane of focus becomes parallel to the floor. Also, the upper edge and the lower edge of the range of depth of field are parallel to the focus plane and the floor (a state that can be regarded as parallel). Strictly speaking, the depth of field on the front side (upper side) and the depth of field on the back side (lower side) of the focus plane are different. Even if the center of the depth of field in the depth direction is regarded as the focal plane, no major problems arise. Therefore, here, the center of the range of depth of field in the depth direction is used as the focus plane.

Here, when the focal plane is raised to the position of the focal plane height H as described above, in order to realize the depth of field set on the tilt shooting setting screen, the aperture value F of the aperture 113 is set to full aperture. may need to be set to a value greater than A method of calculating the aperture value F for realizing the depth of field set on the tilt shooting setting screen will be described below. The timing for driving the aperture 113 so as to obtain the calculated aperture value F is, for example, after execution of step S18.

FIG. 9 is a diagram illustrating a method of calculating the aperture value F that achieves the depth of field (D2) set on the tilt photography setting screen.

The aperture value F can be calculated by Equation (4).

ここで、ｆは光学系１１０の焦点距離、δは最小錯乱円径（撮像素子に依存する固定値）、θはデジタルカメラ１００の俯角（カメラ俯角）、Ｆは絞り１１３の絞り値、Ｈｃは床面から光学系１１０のレンズ主点までの距離（カメラ高さ）、Ｈはピント面の床面からの距離（ピント面高さ）である。ｆの値は、内蔵メモリ２３０に予め格納されている。θとしては、チルト撮影設定画面で設定されたカメラ俯角が用いられる。Ｈｃとしては、チルト撮影設定画面で設定されたカメラ高さが用いられる。Ｈとしては、チルト撮影設定画面で設定されたピント面高さが用いられる。

Here, f is the focal length of the optical system 110, δ is the minimum circle of confusion diameter (a fixed value that depends on the imaging device), θ is the depression angle of the digital camera 100 (camera depression angle), F is the aperture value of the diaphragm 113, and Hc is The distance (camera height) from the floor to the lens principal point of the optical system 110, and H is the distance of the focus plane from the floor (focus plane height). The value of f is prestored in the built-in memory 230 . As θ, the camera depression angle set on the tilt shooting setting screen is used. As Hc, the camera height set on the tilt shooting setting screen is used. As H, the focus plane height set on the tilt shooting setting screen is used.

1-3. Effects, etc. As described above, the digital camera 100 of the present embodiment includes the image sensor 130 that captures the subject image formed on the imaging surface to generate image data, and the focus lens 112. an optical system 110 that forms an image, a focus lens driving unit 122 that drives the focus lens 112 in the optical axis direction, and an image pickup device tilting device that rotates and tilts the image pickup surface of the image pickup device 130 around an axis that is not parallel to the optical axis. and a controller 180 (controller) that controls the focus lens driving section 122 and the imaging element tilting section 160 . The controller 180 (a) causes the focus lens driving section 122 to move the focus lens 112 so as to focus on the first predetermined position P1 on the floor surface (an example of the reference plane) of the subject, and then (b) the optical axis. The focus position is moved from the first predetermined position P1 to the second predetermined position P2 based on the positional relationship between the second predetermined position P2 and the first predetermined position P1 where the height from the floor surface is a predetermined height above. , the focus lens 112 is moved by the focus lens drive unit 122, and then (c) the image sensor tilt unit 160 is moved so that the focus plane becomes a plane parallel to the floor surface and at a predetermined height. The imaging surface of the imaging device 130 is tilted.

According to the digital camera 100 of this embodiment having such a configuration, it is possible to perform tilt photographing effectively using both the front side portion and the rear side portion of the depth of field. Therefore, it is possible to obtain an image in which the subject on the floor is in focus while suppressing an increase in the ISO sensitivity.

In the present embodiment, before executing (a), the controller 180 causes the image pickup element tilting section 160 to take an image so that the focus plane is a plane that is perpendicular to the floor surface and includes the first predetermined position P1. The imaging plane of element 130 is tilted.

As a result, the depth of field in the direction parallel to the floor surface around the first predetermined position P1 becomes shallow. Therefore, in (a), when the focus lens driver 122 moves the focus lens 112 to focus on the first predetermined position P1, the accuracy of focusing on the first predetermined position P1 can be improved.

This embodiment further includes a liquid crystal monitor 220 (an example of an operation unit) that receives an input of a focus plane height (predetermined height).

As a result, the user can appropriately set a desired height as the height of the focus plane according to the height of the subject and the like.

This embodiment further includes a liquid crystal monitor 220 (an example of a second operation unit) that receives input of a desired depth of field.

This allows the user to appropriately set the desired depth of field according to the height of the subject and the like.

(Embodiment 2)
In the first embodiment, the imaging plane of the imaging element 130 is tilted during tilt photography, but in the second embodiment, the principal point plane of the optical system 110 is tilted.

2-1. Configuration FIG. 10 is a diagram showing the configuration of a digital camera according to the second embodiment.

A digital camera 100A of the present embodiment includes an optical system tilting section 300 and a tilt angle sensor 350 instead of the imaging element tilting section 160 of the digital camera 100 of the first embodiment. Differences from the first embodiment will be mainly described below.

The optical system tilting section 300 tilts the entire optical system 110 .

FIG. 11 is a diagram showing an example of the configuration of the optical system tilting section 300. As shown in FIG. Note that FIG. 11 shows a lens 110A in which a plurality of lenses such as the zoom lens 111 and the focus lens 112 included in the optical system 110 are integrated into one.

The optical system tilting unit 300 rotates and tilts the principal point plane of the optical system 110 around the x-axis (an axis perpendicular to the optical axis and on the imaging surface (an example of an axis not parallel to the optical axis)). In the example of FIG. 11, the optical system tilting unit 300 includes a housing frame 310 housing a lens barrel 110B that holds the optical system 110, and an actuator 320 interposed between the housing frame 310 and the lens barrel 110B. . The accommodation frame 310 includes a holding shaft 311 that holds the lens barrel 110B rotatably around the x-axis. The actuator 320 has a piston 321 that moves up and down by an electromagnetic solenoid or the like, and the tip of the piston 321 is connected to one end of the lens barrel 110B in the optical axis direction. According to such a configuration, by vertically moving the piston 321 of the actuator 320, the lens barrel 110B can be rotated and tilted around the x-axis. As a result, the principal plane of the optical system 110 can be rotated and tilted around the x-axis. The optical system tilting unit 300 may be configured in any way as long as it can rotate and tilt the principal point plane of the optical system 110 around an axis that is not parallel to the optical axis. For example, the optical system tilting unit 300 may be configured by a stepping motor, a voice coil motor, or other actuators. When a stepping motor is used as the actuator, open control becomes possible, and along with this, the tilt angle sensor 350 can be made unnecessary.

The tilt angle sensor 350 is a sensor for detecting the tilt angle of the principal point plane of the optical system 110 . The tilt angle sensor 350 can be implemented by, for example, magnets and Hall elements.

2-2. Operation FIG. 12 is a flowchart for explaining the flow of the tilt photographing operation. In order to facilitate understanding of the operation flow, the same steps as those in the first embodiment will also be described as appropriate. The same steps as in Embodiment 1 are given the same reference numerals, and different steps are given different reference numerals.

When the tilt shooting function is activated, the controller 180 reads the tilt shooting setting information set on the tilt shooting setting screen of FIG. 3 from the built-in memory 230 (S11).

The controller 180 calculates a tilt angle φ0 of the principal point plane for making the focus plane a plane perpendicular to the floor surface and including the first predetermined position P1 (S12A).

FIG. 13 is a diagram explaining a method of calculating the tilt angle φ0 of the principal point plane. According to the Scheimpflug principle, in order to make the focal plane a plane perpendicular to the floor surface and containing the first predetermined position P1, on the vertical focal plane, an extension line of the imaging plane and an extension line of the principal point plane are They should intersect at one point. In this embodiment, by tilting the principal point plane from the state indicated by the dashed line parallel to the imaging plane to the state indicated by the solid line, the extension line of the principal point plane is aligned with the intersection of the extension line of the imaging plane and the focus plane. let them cross The tilt angle φ0 of the principal point plane at this time is equal to the included angle (φ0) around the intersection of the extension line of the imaging plane and the extension line of the principal point plane.

The tilt angle φ0 can be calculated by Equation 1 described above.

In this embodiment, Hc is the distance (camera height) from the floor to the center of the imaging surface of the imaging device 130 .

The controller 180 drives the lens by the optical system tilting section 300 so that the tilt angle of the principal point plane becomes φ0 (S13A).

The controller 180 causes the focus lens driving section 122 to move the focus lens 112 so that the contrast value of the image output from the image sensor 130 is maximized (S14). That is, the controller 180 performs autofocus control for focusing on the first predetermined position P1.

The controller 180 moves the focus position from the first predetermined position P1 to the second predetermined position P2 having a height H (focus plane height) from the floor on the optical axis. to the lens principal point is calculated (S15).

FIG. 14 is a diagram explaining a method of calculating the optical axis direction distance t2. FIG. 14(a) shows the state before moving the focus position, and FIG. 14(b) shows the state after moving the focus position.

The optical axis direction distance t2 can be calculated by Equation 2 described above.

The controller 180 causes the focus lens driver 122 to move the focus lens 112 so that the distance in the optical axis direction from the center of the imaging plane to the lens principal point is t2 (S16). As a result, the focus position is moved from the first predetermined position P1 to the second predetermined position P2 based on the positional relationship between the second predetermined position P2 and the first predetermined position P1.

The controller 180 calculates the tilt angle φ1 of the principal point plane for making the focus plane a plane parallel to the floor surface and at the height H (focus plane height) (S17A).

FIG. 15 is a diagram explaining a method of calculating the tilt angle φ1 of the principal point plane. According to the Scheimpflug principle, in order to make the focal plane parallel to the floor and at a height H (height of the focal plane), on the focal plane at this height H (height of the focal plane) , the extension line of the imaging plane and the extension line of the principal point plane should intersect at one point. In this embodiment, by tilting the principal point plane from the state indicated by the dashed line parallel to the imaging plane to the state indicated by the solid line, the extension line of the principal point plane is aligned with the intersection of the extension line of the imaging plane and the focus plane. let them cross The tilt angle φ1 of the principal point plane at this time is equal to the included angle (φ1) around the intersection of the extension line of the imaging plane and the extension line of the principal point plane.

The tilt angle φ1 can be calculated by Equation 3 described above.

In this embodiment, Hc is the distance (camera height) from the floor to the center of the imaging surface of the imaging element 130 .

The controller 180 causes the optical system tilting section 300 to tilt the optical system 110 so that the tilt angle of the principal point plane becomes φ1 (S18A). As a result, as shown in FIG. 15, the plane of focus becomes parallel to the floor. Also, the upper edge and the lower edge of the range of depth of field are parallel to the focus plane and the floor (a state that can be regarded as parallel).

Here, when the focal plane is raised to the position of the focal plane height H as described above, in order to realize the depth of field set on the tilt shooting setting screen, the aperture value F of the aperture 113 is set to full aperture. may need to be set to a value greater than A method of calculating the aperture value F for realizing the depth of field set on the tilt shooting setting screen will be described below. The timing for driving the aperture 113 so as to obtain the calculated aperture value F is, for example, after execution of step S18.

FIG. 16 is a diagram illustrating a method of calculating the aperture value F that achieves the depth of field (D2) set on the tilt photography setting screen.

The aperture value F can be calculated by Equation 4 described above.

Here, Hc is the distance (camera height) from the floor to the center of the imaging surface of the imaging device 130 .

2-3. Effects, etc. As described above, the digital camera 100A of the present embodiment includes the image sensor 130 that captures the subject image formed on the imaging surface to generate image data, and the focus lens 112. an optical system 110 that forms an image, a focus lens driving unit 122 that drives the focus lens 112 in the optical axis direction, and an optical system that rotates and tilts the principal point plane of the optical system 110 about an axis that is not parallel to the optical axis. A tilting section 300 and a controller 180 that controls the focus lens driving section 122 and the optical system tilting section 300 are provided. The controller 180 (a) causes the focus lens driving section 122 to move the focus lens 112 so as to focus on the first predetermined position P1 on the floor surface (an example of the reference plane) of the subject, and then (b) the optical axis. The focus position is moved from the first predetermined position P1 to the second predetermined position P2 based on the positional relationship between the second predetermined position P2 and the first predetermined position P1 where the height from the floor surface is a predetermined height above. , the focus lens drive unit 122 moves the focus lens 112, and then (c) the optical system tilt unit 300 is moved so that the focus plane becomes a plane parallel to the floor surface and at a predetermined height. The principal plane of the optical system 110 is tilted.

According to the digital camera 100 of this embodiment having such a configuration, it is possible to perform tilt photographing effectively using both the front side portion and the rear side portion of the depth of field. Therefore, it is possible to obtain an image in which the subject on the floor is in focus while suppressing an increase in the ISO sensitivity.

In the present embodiment, before executing (a), the controller 180 causes the optical system tilting unit 300 to move the optical system so that the focus plane is a plane that is perpendicular to the floor surface and includes the first predetermined position P1. The principal plane of system 110 is tilted.

As a result, the depth of field in the direction parallel to the floor surface centered on the first predetermined position P1 becomes the shallowest. Therefore, in (a), when the focus lens driver 122 moves the focus lens 112 to focus on the first predetermined position P1, the accuracy of focusing on the first predetermined position P1 can be improved.

(Other embodiments)
As described above, Embodiment 1 has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which modifications, replacements, additions, omissions, etc. are made as appropriate. Also, it is possible to combine the constituent elements described in the first embodiment to form a new embodiment. Therefore, other embodiments will be exemplified below.

(1) In Embodiment 1, the configuration for tilting the imaging element 130 was described, and in Embodiment 2, the configuration for tilting the optical system 110 was described. However, both the imaging element 130 and the optical system 110 may be tilted.

(2) In the above embodiment, the tilt shooting setting screen allows the user to input the camera height, camera depression angle, focus plane height, and depth of field using the touch sensor function of the liquid crystal monitor 220. bottom. However, the imaging device may be provided with a camera height sensor for detecting the camera height from the ground, and the controller may automatically set the camera height based on the detected camera height. Alternatively, the imaging apparatus may be provided with a camera depression angle sensor for detecting the camera depression angle, and the controller may automatically set the camera depression angle based on the detected camera depression angle. In addition, when the bottom edge of the depth of field is aligned with the floor surface, the controller calculates the height of the focus plane based on the set depth of field, and automatically adjusts the height of the focus plane obtained by calculation. You can set it with

(3) In the above embodiment, contrast AF is used as an autofocus method, but phase difference AF or image plane phase difference AF may be used.

(4) In the above embodiment, a lens-integrated camera has been described, but the present disclosure can also be applied to a lens-interchangeable camera. In the case of an interchangeable-lens camera, information on the focal length of the optical system can be acquired by the camera body communicating with the interchangeable lens.

(5) In the above embodiment, the case where the reference plane is the floor surface of the stadium has been described. However, the reference plane may be any plane other than a horizontal plane such as the floor. In this case, the height from the reference plane is the distance in the direction perpendicular to the reference plane.

(6) In the above embodiments, a digital camera was described as an example of an imaging device, but the imaging device is not limited to this. The concept of the present disclosure can be applied to various imaging devices capable of capturing moving images, such as digital video cameras, smart phones, and wearable cameras.

(7) In the first embodiment described above, the imaging element tilting unit 160 moves the imaging surface (sensor surface) of the imaging element 130 along the x-axis (an axis perpendicular to the optical axis and on the imaging surface (an axis that is not parallel to the optical axis). One example is to rotate and tilt around )). However, in the present disclosure, the axis of rotation need not be perpendicular to the optical axis, and may be in a direction that intersects the optical axis. That is, the axis of rotation should not be parallel to the optical axis.

(8) In the second embodiment described above, the optical system tilting unit 300 moves the principal point plane of the optical system 110 along the x-axis (the axis perpendicular to the optical axis and on the imaging surface (an example of an axis that is not parallel to the optical axis)). rotate around and tilt. However, in the present disclosure, the axis of rotation need not be perpendicular to the optical axis, and may be in a direction that intersects the optical axis. That is, the axis of rotation should not be parallel to the optical axis.

(9) In the first embodiment described above, an example in which the processes of steps S12 and S13 are performed has been described, but the processes of steps S12 and S13 are not essential in the present disclosure. Further, in steps S12 and S13, the imaging plane may be tilted so that the angle of the focal plane becomes closer to perpendicular to the floor than when the imaging plane is not tilted (the focal plane may be tilted relative to the floor). may not be vertical). Even in this case, the effect of narrowing the depth of field in the direction parallel to the floor surface can be obtained.

(10) In the second embodiment described above, an example in which the processes of steps S12A and S13A are performed has been described, but the processes of steps S12A and S13A are not essential in the present disclosure. Further, in steps S12A and S13A, the principal point plane may be tilted so that the angle of the focus plane becomes closer to being perpendicular to the floor than when the principal plane is not tilted (when the focus plane is the floor surface). (It does not have to be perpendicular to the Even in this case, the effect of narrowing the depth of field in the direction parallel to the floor surface can be obtained.

As described above, the embodiment has been described as an example of the technique of the present disclosure. To that end, the accompanying drawings and detailed description have been provided. Therefore, among the components described in the attached drawings and detailed description, there are not only components essential for solving the problem, but also components not essential for solving the problem in order to illustrate the above technology. can also be included. Therefore, it should not be immediately recognized that those non-essential components are essential just because they are described in the attached drawings and detailed description. In addition, the above-described embodiments are intended to illustrate the technology of the present disclosure, and various modifications, replacements, additions, omissions, etc. can be made within the scope of the claims or equivalents thereof.

INDUSTRIAL APPLICABILITY The present disclosure can be widely used in imaging devices that capture still images and moving images.

100, 100A Digital camera 110 Optical system 110A Lens 110B Lens barrel 111 Zoom lens 112 Focus lens 113 Aperture 121 Zoom lens driver 122 Focus lens driver 123 Aperture driver 130 Image sensor
140 ADCs
150 TG
160 image sensor tilting parts 161, 162 fixed frame 163 movable plates 164, 165, 166, 167 magnets 168, 169 coil 170 tilt angle sensor 180 controller 190 card slot 200 memory card 210 release button 220 liquid crystal monitor 230 built-in memory 300 optical system tilting Part 310 Housing frame 311 Holding shaft 320 Actuator 321 Piston 350 Tilt angle sensor

Claims (4)

an imaging device that captures a subject image formed on an imaging surface and generates image data;
an optical system that includes a focus lens and forms the subject image on the imaging surface;
a focus lens driving unit that moves the focus lens in an optical axis direction;
an imaging element tilting unit that rotates and tilts the imaging surface of the imaging element about an axis that is not parallel to the optical axis;
a control unit that controls the focus lens driving unit and the imaging element tilting unit,
The control unit
(a) causing the focus lens driving unit to move the focus lens so as to focus on a first predetermined position on the reference plane of the object;
(b) shifting the focus position from the first predetermined position to the second predetermined position based on the positional relationship between the first predetermined position and a second predetermined position where the height from the reference plane on the optical axis is a predetermined height; causing the focus lens driver to move the focus lens to a position; and
(c) tilting the imaging surface of the imaging element by the imaging element tilting unit so that the focus plane becomes a plane parallel to the reference plane and at the predetermined height ;
Before executing (a) above,
tilting the imaging surface of the imaging device by the imaging device tilting unit so that the focus plane is a plane that is perpendicular to the reference plane and includes the first predetermined position;
Imaging device. an imaging device that captures a subject image formed on an imaging surface and generates image data;
an optical system that includes a focus lens and forms the subject image on the imaging surface;
a focus lens driving unit that moves the focus lens in an optical axis direction;
an optical system tilting unit that rotates and tilts the principal point surface of the optical system about an axis that is not parallel to the optical axis;
a control unit that controls the focus lens driving unit and the optical system tilting unit,
The control unit
(a) causing the focus lens driving unit to move the focus lens so as to focus on a first predetermined position on the reference plane of the object;
(b) shifting the focus position from the first predetermined position to the second predetermined position based on the positional relationship between the first predetermined position and a second predetermined position where the height from the reference plane on the optical axis is a predetermined height; causing the focus lens driver to move the focus lens to a position; and
(c) causing the optical system tilting unit to tilt the principal point plane of the optical system so that the focus plane becomes a plane parallel to the reference plane and at the predetermined height ;
Before executing (a) above,
causing the optical system tilting unit to tilt the principal point plane of the optical system so that the focus plane is a plane that is perpendicular to the reference plane and includes the first predetermined position;
Imaging device. Further comprising an operation unit that receives an input of the predetermined height,
The imaging device according to claim 1 or 2 . Further comprising a second operation unit that receives input of a desired depth of field,
The imaging device according to any one of claims 1 to 3 .

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