Image capture device and method for controlling image capture device

Abstract

To provide an imaging apparatus in which the position of a focal plane can be adjusted by parallel translating the focal plane while maintaining a subject region when the focal plane is not perpendicular to an optical axis, and a method for controlling an imaging apparatus.SOLUTION: The imaging apparatus includes a sensor driving unit which inclines an imaging sensor with respect to a plane orthogonal to an optical axis of an imaging optical system, a focus lens driving unit which changes a position of a focus lens in the imaging optical system, a range change unit which changes an imaging range, and a control unit which controls the position of the focus lens, the imaging range, and an angle of the imaging sensor so that a first inclined focal plane and a second inclined focal plane after a position of the first inclined focal plane is changed have a predetermined relationship.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an imaging device and a control method for the imaging device, and more particularly to an imaging device having a tilt mechanism for tilting an imaging sensor, and a control method for the imaging device. [Background technology]

[0002] Conventionally, a technique for tilting an image sensor with respect to the optical axis of a lens (sensor tilt) is known.

[0003] When the image sensor is perpendicular to the optical axis (without tilting), the camera can only focus on subjects that are a specific distance away in the direction of the optical axis. In other words, since the focal plane is perpendicular to the optical axis, in the case of a scene with depth, it is not possible to focus on subjects from the foreground to the background.

[0004] On the other hand, by tilting (tilting) the image sensor with respect to the optical axis, the focal plane can be tilted with respect to the optical axis, and the focal plane can be made to be a plane other than a plane perpendicular to the optical axis. In this case, it is possible to focus on subjects at different distances in the optical axis direction. In other words, it is possible to focus on a plane where a distant subject and a close subject exist. Therefore, by tilting the image sensor according to the distribution of subject distances within the angle of view, it is possible to focus on subjects from closer to the subject, as well as subjects further back, compared to when the image sensor is not tilted.

[0005] Such a technique is disclosed, for example, in Patent Document 1. Patent Document 1 discloses a technique for performing sensor tilt shooting by adjusting the tilt of an image sensor so that a plurality of designated regions are in focus. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2016-042194 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the conventional technology disclosed in the above-mentioned Patent Document 1, it is not possible to adjust the position of the focal plane by translating the focal plane aligned with the ground or the like using sensor tilt.

[0008] For example, suppose the tilt angle of the sensor is set so that the focus is on a horizontal surface such as a road or the ground. From that state, it is not possible to change the position of the focus plane while maintaining the tilt of the focus plane so that the focus is on a horizontal surface that is at a specified height from the road or the ground. If sensor tilt is not performed, the position of the focus plane can be moved in parallel in the depth direction simply by moving the focus lens, but if only the focus lens is moved while the sensor is tilted, the tilt of the focus plane changes. If the tilt of the focus plane changes, it may become difficult to obtain the effect of sensor tilt, which is to expand the range in focus in the depth direction by tilting the focus plane in the depth direction.

[0009] Furthermore, even if the focal plane can be moved in parallel to match the ground or the like by tilting the sensor, the range of the subject that can be captured in the depth direction on the focal plane may be narrowed. In other words, tilting the sensor may result in narrowing the depth of the subject that fits within the angle of view, even if you try to focus on a wide range of subjects from the front to the back.

[0010] Therefore, an object of the present invention is to provide an imaging device and a control method for an imaging device that are capable of adjusting the position of the focal plane by translating the focal plane while maintaining the subject area when the focal plane is not perpendicular to the optical axis. [Means for solving the problem]

[0011] In order to achieve the above object, an imaging apparatus according to the present invention includes a sensor driver that tilts an imaging sensor with respect to a plane perpendicular to an optical axis of an imaging optical system, and a focus lens driver that changes a position of a focus lens in the imaging optical system. Imaging method Imaging direction Change Change a first tilt focus plane and a second tilt focus plane after changing the position of the first tilt focus plane; parallel The position of the focus lens and the imaging direction and a control unit that controls the angle of the image sensor. The control unit changes the imaging direction so that a distance in the direction of the second tilt focus plane included in an imaging range of the second tilt focus plane is approximately equal to a distance in the direction of the first tilt focus plane of a range included in the imaging range of the first tilt focus plane. . Effect of the Invention

[0012] According to the present invention, it is possible to provide an imaging device and a control method for an imaging device that are capable of adjusting the position of the focal plane by translating the focal plane while maintaining the subject area when the focal plane is not perpendicular to the optical axis. [Brief description of the drawings]

[0013] [Figure 1] 1 is a configuration diagram of an imaging apparatus according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a diagram illustrating a part of the principle of a first embodiment of the present invention. [Diagram 3] FIG. 1 is a diagram illustrating a part of the principle of a first embodiment of the present invention. [Figure 4] 4 is a flowchart showing a part of a processing flow according to the first embodiment of the present invention. [Diagram 5] FIG. 2 is a diagram illustrating an example of a captured image according to the present invention. [Figure 6] FIG. 11 is a configuration diagram of an imaging apparatus according to a second embodiment of the present invention. [Figure 7] FIG. 11 is a diagram illustrating part of the principle of a second embodiment of the present invention. [Figure 8] FIG. 11 is a configuration diagram of an imaging device according to a third embodiment of the present invention. [Figure 9] FIG. 11 is a diagram illustrating part of the principle of a third embodiment of the present invention. [Figure 10] FIG. 13 is a diagram illustrating part of the principle of a fourth embodiment of the present invention. [Figure 11] FIG. 13 is a diagram illustrating part of the principle of a fourth embodiment of the present invention. [Figure 12] FIG. 2 is a diagram illustrating an example of an operation screen of the imaging device of the present invention. [Figure 13] FIG. 13 is a diagram illustrating part of the principle of a sixth embodiment of the present invention. [Figure 14] FIG. 13 is a diagram illustrating part of the principle of a sixth embodiment of the present invention. [Figure 15] FIG. 13 is a configuration diagram of an imaging device according to a sixth embodiment of the present invention. [Figure 16] FIG. 13 is a diagram illustrating part of the principle of a sixth embodiment of the present invention. [Figure 17] 1A and 1B are diagrams illustrating a part of the principle of an imaging device of a comparative example. [Figure 18] 11A and 11B are diagrams illustrating an example of a captured image of an imaging device of a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. EXAMPLES

[0015] An image pickup apparatus according to a first embodiment of the present invention will now be described with reference to Fig. 1. Fig. 1 is a configuration diagram showing an example of the functional configuration of an image pickup apparatus according to the present invention.

[0016] In this embodiment, the position of the focus lens and the sensor tilt angle are set in advance so that the focus is on a reference plane (reference plane) such as a road or the ground. Then, by instructing the amount of change in the position of the focus plane, the focus plane is translated from the reference plane by an amount equivalent to the amount of change. The amount of change in the position of the focus plane is, for example, the distance from the reference plane.

[0017] The imaging device 1000 includes an optical unit 1001 , a control unit 1002 , and a drive unit 1003 .

[0018] The optical unit 1001 is composed of a lens 101 and an image sensor 102, and captures an image of input light such as reflected light from a subject, converts it into an image signal, and outputs it.

[0019] A lens 101 as an imaging optical system collects input light and forms a subject image on an imaging sensor 102. The lens 101 may be composed of multiple lenses, and in this embodiment, the lens 101 can focus on a subject at a predetermined subject distance by moving the position of a focus lens included in the lens 101.

[0020] The image sensor 102 converts an object image formed on an imaging surface consisting of a plurality of imaging elements arranged two-dimensionally into an electrical signal, thereby generating and outputting an image signal of the object.

[0021] The control unit 1002 serving as a control section includes an imaging direction changing section 103 , a focus position changing section 104 , and a sensor angle changing section 105 .

[0022] The imaging direction changing unit 103 as a range changing unit acquires an instruction to change the position of the focal plane (a focal plane change instruction), and calculates the amount of change in the tilt angle based on the amount of change in the position of the focal plane. The imaging direction changing unit 103 instructs the tilt driving unit 106 to change the orientation of the imaging device 1000 by the calculated amount of change. The imaging direction changing unit 103 also outputs the amount of change in the tilt angle to the focal position changing unit 104. Note that the focal plane change instruction is the amount of change in the position of the focal plane, and is an amount indicating the distance from the reference plane.

[0023] The focal position changing unit 104 calculates the position of the focus lens based on the change amount of the tilt angle and the change amount of the focal plane position acquired from the shooting direction changing unit 103, and instructs the focus driving unit 107 to drive the focus lens to the calculated position. In addition, the focal position changing unit 104 outputs the position of the focus lens to the sensor angle changing unit 105.

[0024] The sensor angle changing unit 105 calculates the elevation angle of the image sensor 102 based on the amount of change in the tilt angle acquired from the shooting direction changing unit 103 and the position of the focus lens acquired from the focus position changing unit 104. The sensor angle changing unit 105 instructs the sensor driving unit 108 to drive the image sensor 102 to achieve the calculated elevation angle.

[0025] The driving unit 1003 is made up of a tilt driving section 106, a focus driving section 107, and a sensor angle changing section .

[0026] The tilt driving unit 106 is a tilt driving mechanism that changes the tilt direction of the imaging device 1000, and changes the shooting direction (tilt direction) of the imaging device based on an instruction from the imaging direction changing unit 103.

[0027] The focus lens driving unit 107 is a focus lens driving mechanism that drives the focus lens included in the lens 101 , and drives the lens 101 based on an instruction from the focus position changing unit 104 .

[0028] The sensor angle change unit 108 is a tilt drive mechanism that changes the tilt angle of the image sensor 102, and drives the image sensor 102 to change the tilt angle of the image sensor 102 based on an instruction from the sensor angle change unit 105. In other words, the sensor angle change unit 108 tilts the image sensor 102 with respect to a plane perpendicular to the optical axis of the lens 102.

[0029] Next, the amount of change in the tilt angle, the position of the focus lens, and the elevation angle will be specifically described with reference to Figures 2 and 3. Figure 2 shows the state where the focal plane is aligned with the reference plane. Figure 3 shows the state where the focal plane has been translated by a distance H from the reference plane.

[0030] Given the subject distance (a), the angle (θ) between the optical axis and the perpendicular to the reference plane, the angle of view (ω), and the focal length (f), the tilt angle (α) when aligning the focal plane with the reference plane and the position of the focus lens (b) can be expressed as follows:

[0031]

number

[0032] Further, the distance (Ln) to the near end and the distance (Lf) to the far end of the range of the focal plane (subject area) included in the angle of view of the imaging device are expressed as follows.

[0033]

number

[0034] Next, a state in which the focal plane is translated by a distance H from the reference plane will be described with reference to FIG.

[0035] The amount of change (φ) in the tilt angle is calculated so that the distance (Ln') to the front end of the range (subject area) of the focal plane included in the angle of view of the imaging device obtained by translating the focal plane by a distance H from the reference plane becomes equal to Ln when the reference plane is focused. Specifically, the imaging direction change unit 103 calculates the amount of change (φ) in the tilt angle according to the amount of change (H) in the position of the focal plane so as to satisfy the following formula.

[0036] When the focal plane is translated a distance H from the reference plane, the subject distance (A') is the angle (θ') between the optical axis and the reference plane, the angle of view (ω) is the focal length (f), and the distance (Ln') to the front end of the focal plane range (subject area) is expressed as follows:

[0037]

number

[0038] Next, the focal position changing unit 104 calculates the position (B') of the focus lens when the focal plane is translated by a distance H as follows.

[0039]

number

[0040] Furthermore, the sensor angle change unit 105 calculates the elevation angle (αp′) when the focal plane is translated by the distance H as follows.

[0041]

number

[0042] In this embodiment, the shooting direction change unit 103, the focal position change unit 104, and the sensor angle change unit 105 calculate each control amount based on the above-mentioned formula, but the method of calculating each control amount is not limited to this. The control amount calculated based on the formula may be stored as table data in advance, and each control amount corresponding to the change amount of the position of the focal plane may be read from the table data. The formula for calculating each control amount is not limited to the above-mentioned one, and may be, for example, a more simplified version of the above-mentioned formula. Each control amount may be calculated without using a formula. For example, a control amount obtained experimentally may be stored as table data. When installing the imaging device in an actual installation location, a preferable control amount may be determined while checking the captured image, and stored in the table data.

[0043] Next, an example of a processing flow of the imaging device according to this embodiment will be described with reference to Fig. 4. Fig. 4 is a flowchart showing a part of the processing flow of the imaging device according to this embodiment.

[0044] In S101, the imaging direction change unit 103 calculates and stores the distance (W1) in the focal plane direction of the range included in the angle of view of the imaging device, of the focal plane before changing the position of the focal plane.

[0045] In S102, the drive unit 1002 determines whether or not there is an instruction to change the focal plane, and if there is an instruction to change the focal plane, the process proceeds to S103.

[0046] In S103, the imaging direction change unit 103 calculates the distance (W2) in the focal plane direction of the range of the focal plane after the position of the focal plane is changed and included in the angle of view of the imaging device.

[0047] In S104, the shooting direction change unit 103 calculates the difference between W1 and W2, and determines whether the difference is equal to or greater than a predetermined value. If the difference is equal to or greater than a predetermined value, the process proceeds to S105, and if not, the process proceeds to S107.

[0048] In S105, the imaging direction change unit 103 calculates the change amount of the tilt angle.

[0049] In S106, W1 stored in the imaging direction changing unit 103 is updated to W2 calculated in S103.

[0050] In S107 , the focal position changing unit 104 calculates the position of the focus lens included in the lens 101 .

[0051] In S108, the sensor angle change unit 105 calculates the sensor angle (tilt amount).

[0052] Thereafter, tilt driver 106 changes the tilt direction of the imaging device based on the calculated change amount (φ) of the tilt angle. Focus driver 107 moves the focus lens to a focus lens position (B'). Sensor driver 108 rotates imaging sensor 102 to achieve a flap angle (αp'). Specifically, control unit 1002 simultaneously moves tilt driver 106, focus driver 107, and sensor driver 108 in accordance with the change amount of the focal plane position from the user. Control unit 1002 may also shift the timing of starting operations so that the change in the tilt direction of imaging device 1000, the change in the focus lens position, and the change in the flap angle are completed simultaneously.

[0053] With the above configuration, the imaging device of this embodiment controls the distance of the focal plane included in the field of view of the imaging device in the focal plane direction by making the position of the focal plane, the tilt angle of the imaging device, and the angle of the sensor have a predetermined relationship according to the change amount of the position of the focal plane. More specifically, the distance of the focal plane included in the field of view of the imaging device in the focal plane direction before changing the position of the focal plane and the distance of the focal plane included in the field of view of the imaging device after changing the position of the focal plane are controlled to be approximately constant.

[0054] This makes it possible for the imaging device of this embodiment to translate the position of the focal plane while keeping the distance (subject area) of the focal plane in the focal plane direction included in the angle of view of the imaging device substantially constant.

[0055] Furthermore, when the position of the focal plane is changed, if the size of the subject area changes by a predetermined amount or more, the tilt driver 106 controls to change the tilt angle. This makes it possible to prevent the angle of view from changing frequently.

[0056] The effects of the present invention will be described below with reference to a comparative example. As shown in Fig. 17, if the imaging direction is kept fixed when the position of the focal plane is moved, the subject area will be narrowed and the position of the subject area will also change. In such a case, as shown in Fig. 18, the distance in the depth direction of the subject that can be imaged for a specific focal plane will be narrowed. In other words, although it is attempted to focus on a wide range of subjects from the front to the back by tilting the sensor, the depth of the subject that fits within the angle of view itself will be narrowed, and there is a risk that the effect of sensor tilting will be lost.

[0057] For example, when the focal plane is the ground as in the left image of Figure 18, it is possible to focus on subjects between 10m and 30m above the road surface. However, when the focal plane is translated to the height of a human face as in the right image of Figure 18, it is only possible to focus on subjects between 10m and 20m away. In other words, by translating the focal plane, the range of subjects that can be focused on (subject area) becomes narrower.

[0058] On the other hand, in the imaging device of the present invention, when the position of the focal plane is moved, the imaging direction is changed in conjunction with the movement, as shown in Fig. 5. Therefore, even if the position of the focal plane is translated to the height of a human face as shown in the right diagram of Fig. 5, it is possible to focus on a subject (a human face) at a distance of 10 m to 30 m, just as when the focal plane is the ground.

[0059] An example of a use case envisioned by the present invention will be described below.

[0060] For example, a use case of a surveillance camera to which the present invention is applied is one in which the position of the focal plane is automatically changed depending on the surveillance purpose. For example, assume that a passageway through which people pass is being photographed as shown in FIG. 5. If the surveillance purpose is to photograph people, such as searching for suspicious people, the focal plane is moved to the height of the person's face as shown in the right diagram of FIG. 5. On the other hand, if the surveillance purpose is to photograph objects on the road, such as searching for suspicious objects or lost property, the focal plane is moved to the road (ground) as shown in the left diagram of FIG. 5. By implementing in this way, a captured image suitable for each surveillance purpose can be obtained.

[0061] Alternatively, an example of a use case of an industrial camera to which the present invention is applied is image inspection (visual inspection) of items manufactured in a factory or the like. For example, consider a case where products are stacked vertically for storage in order to save space in a factory, and the products are photographed with a camera and inspected using image analysis or other means to prevent the inclusion of defective products. As shown in FIG. 3, the imaging device of the present invention can take images while vertically moving the height of the focal plane. Therefore, a high-quality photographed image focused according to the position and height of the stacked products can be obtained, and the accuracy of image analysis can be improved. In addition, since the products can be installed by stacking them vertically, multiple products can be inspected without moving them. EXAMPLES

[0062] Next, an imaging device according to a second embodiment of the present invention will be described with reference to Fig. 6. In the first embodiment, the imaging range is changed by changing the direction of the imaging device 1000 using the imaging direction change unit 103, but in the second embodiment, the focal length is changed by changing the position of the zoom lens using the angle of view change unit 203. Note that the same functional units as those in the first embodiment are given the same reference numerals, and their description will be omitted. Fig. 6 is a configuration diagram showing an example of the functional configuration of the imaging device according to this embodiment.

[0063] The lens 201 includes a focus lens and a zoom lens. By moving the position of the focus lens, it is possible to focus on a subject at a predetermined subject distance. Also, by moving the position of the zoom lens, it is possible to change the focal length and the angle of view.

[0064] The angle-of-view changing unit 203, which serves as a range changing unit, receives an instruction to change the position of the focal plane (instruction to change the focal plane), calculates the angle of view based on the amount of change in the position of the focal plane, and instructs the zoom lens driving unit 206 to drive the zoom lens to obtain the calculated angle of view. The angle-of-view changing unit 203 also outputs the angle of view to the focal position changing unit 104.

[0065] The zoom lens driving unit 206 is a zoom mechanism that changes the angle of view of the image capturing device 1000, and changes the focal length by moving the position of the zoom lens based on an instruction from the angle of view changing unit 203.

[0066] The angle of view (ωz) after the focal plane has moved is determined as follows. As shown in FIG. 7, when the reference plane is in focus and the angle of view is (ω), the near end (Ln) and the far end (Lf) of the subject area are defined as the near end (Lnz) and the far end (Lfz) of the subject area after the focal plane is moved by H and the angle of view is changed to (ωz). In addition, the focal length after the angle of view is changed to (ωz) is defined as (fz). The angle of view (ωz) after the focal plane has moved is determined so as to satisfy the following formula.

[0067]

number

[0068] By satisfying the above formula, as shown in FIG. 7, the size of the subject area after the focal plane is moved can be controlled to be equal to or larger than the size of the subject area before the focal plane is moved. EXAMPLES

[0069] Next, an imaging device according to a third embodiment of the present invention will be described with reference to Fig. 8. In this embodiment, as a means for changing the position of the focal plane, a mechanism (tilt mechanism) serving as a direction change unit for changing the orientation of the imaging device is controlled to change the tilt angle. Also, as a means for changing the imaging range of the imaging device, the focal length is changed by changing the position of the zoom lens. Fig. 8 is a configuration diagram showing an example of the functional configuration of the imaging device according to this embodiment. Note that the same reference numerals are used for the same functional units as in embodiment 1 or embodiment 2, and their description will be omitted.

[0070] The focal position changing unit 304 calculates the change amount (Ψ) of the orientation of the imaging device based on the change amount of the focal plane position, and instructs the tilt driving unit 307 to drive the imaging direction by the calculated change amount. The focal position changing unit 304 also outputs the change amount (Ψ) of the imaging device to the sensor angle changing unit 105.

[0071] The tilt driving unit 307 is a tilt driving mechanism that changes the orientation of the imaging device, and changes the position of the focal plane by changing the orientation of the imaging device based on an instruction from the focal position changing unit 304.

[0072] With the above configuration, when the orientation of the imaging device is changed to change the position of the focal plane, the angle of view is changed by moving the zoom lens included in lens 201 according to the amount of change in the orientation of the imaging device, as shown in Fig. 9. This makes it possible to control the size of the subject area after the focal plane is moved so that it is equal to or larger than the size of the subject area before the focal plane is moved, as shown in Fig. 9. EXAMPLES

[0073] Next, an imaging device according to a fourth embodiment of the present invention will be described with reference to Fig. 10 and Fig. 11. In this embodiment, the functional configuration is the same as in the first to third embodiments.

[0074] First, at least a part of the focal plane included in the angle of view is set as the subject area. Then, when the focal position changing unit 104 or the focal position changing unit 304 changes the position of the focal plane, the position of the focal plane is limited to a predetermined range so that the range corresponding to the subject area of ​​the focal plane after the focal plane change falls within the angle of view.

[0075] When changing the position of the focal plane, the focal position changing unit 104 limits the amount of movement of the focus lens so that the range corresponding to the subject area of ​​the focal plane after the focal plane change falls within the angle of view. Specifically, as shown in FIG. 10, the focus lens position (b) is limited so as not to be larger than BM. This limits the amount of movement of the focal plane from the reference plane to less than the "upper height limit" in FIG. 10. Note that BM in such a case can be calculated under the condition that the above Lf when the amount of movement of the focal plane is H is greater than or equal to the distance (Df) to the far end of the subject area.

[0076]

number

[0077] Furthermore, when changing the position of the focal plane, the focal position changing unit 304 limits the change amount of the orientation (tilt angle) of the imaging unit so that the range corresponding to the subject area of ​​the focal plane before changing the focal plane falls within the angle of view. Specifically, as shown in Fig. 11, the change amount (φ) of the orientation of the imaging unit is limited so as not to be larger than φM. This limits the movement amount of the focal plane from the reference plane to less than the "upper height limit" in Fig. 11. Note that φM in such a case can be calculated under the condition that Ln, when the movement amount of the focal plane is H, is less than the distance (Dn) to the near end of the subject area.

[0078]

number

[0079] By implementing the above, it is possible to change the position of the focal plane within a range in which the subject area falls within the angle of view. In other words, it is possible to prevent the subject area from going outside the angle of view when changing the position of the focal plane. EXAMPLES

[0080] Next, with reference to FIG. 12, an imaging device according to a fifth embodiment of the present invention will be described.

[0081] FIG. 12 is a diagram showing an example of an operation screen of the imaging device of the present invention. As shown in FIG. 12, the operation screen of the imaging device of the present invention is provided with a viewer for a captured image and a focus adjustment function. The focus adjustment function as an instruction unit can adjust the position of the focus plane by pressing a button on the screen. The buttons for the focus adjustment function include two buttons, Far / Near, which are operated when the focus plane and the optical axis are perpendicular (no tilt), and two buttons, High / Low, which are operated when the focus plane and the optical axis are not perpendicular (with tilt). The Far / Near buttons translate the focus plane in directions that are directly opposite each other. The High / Low buttons translate the focus plane in directions that are directly opposite each other. The method of translating the focus plane when operating the High / Low buttons (with tilt) is as in the above-mentioned embodiment.

[0082] With the four buttons as described above prepared, in this embodiment, control is performed so that only one of the Far / Near button or the High / Low button is enabled (operable). That is, when the focal plane and the optical axis are perpendicular (no tilt), the Far / Near button is enabled and the High / Low button is disabled (inoperable). On the other hand, when the focal plane and the optical axis are not perpendicular (tilt), the Far / Near button is disabled and the High / Low button is enabled.

[0083] The Far / Near button changes the position of the focus lens, and if only the focus lens is moved while the sensor is tilted, the inclination of the focal plane may change, which may result in a change in the depth of field. Therefore, in this embodiment, when the focal plane and the optical axis are not perpendicular (when tilted), the Far / Near button is disabled and the High / Low button is enabled.

[0084] This makes it possible to prevent the inclination of the focal plane from being unintentionally changed when tilting the sensor, and to always move the position of the focal plane in parallel according to the state of the sensor tilt. EXAMPLES

[0085] Next, a use case of the imaging device according to the sixth embodiment of the present invention will be described with reference to FIGS.

[0086] The upper part of Fig. 13 shows use cases of the first to fifth embodiments. As already explained, by performing sensor tilt, even when a close subject and a distant subject exist within the imaging range, a captured image in which both the close subject and the distant subject are in focus can be obtained. As an example, in the case of no tilt, only the subject 20 is in focus, but in the case of tilt, the subjects 10, 20, and 30 are in focus. In such a case, the subject is photographed from a relatively far distance.

[0087] On the other hand, the lower part of FIG. 13 shows a use case of the sixth embodiment. This case is a case where an object is photographed from a close distance, for example, a case where a product manufactured in a factory is photographed with a camera to perform an appearance inspection. As an example, a case is shown where objects 11, 21, and 31 are photographed individually while changing the orientation of the imaging device when photographing at a close distance. When photographing at a close distance, only a narrow range can be photographed and only one object can be photographed at a time, so the orientation of the imaging device is changed. Also, when photographing at a close distance, the depth of field becomes shallow. Therefore, when there is no tilt, even if there is only one object to be photographed, some parts of the object are in focus and some parts are not, but when there is tilt, an example is shown where the entire object being photographed is in focus.

[0088] FIG. 14 also shows a use case of the sixth embodiment. This case is also a case where a subject is photographed from a close distance, for example, a case where manufactured products, luggage, etc. are stacked and the top item is photographed. The horizontal position of the subject is constant, and the height of the subject to be photographed (height of the focal plane) is changed by changing the orientation of the imaging device. Since close-distance photography is performed, the depth of field is shallow without tilt, and some parts of the subject are in focus and some are not, as in the example shown in the lower part of FIG. 13.

[0089] An imaging device according to a sixth embodiment of the present invention will be described with reference to Fig. 15. In the first embodiment, the imaging direction changing unit 103 acquires an instruction to change the position of the focal plane (instruction to change the focal plane), and calculates the amount of change in the tilt angle based on the amount of change in the position of the focal plane. On the other hand, in the sixth embodiment, the focal plane changing unit 409 acquires an instruction to change the tilt angle (instruction to change the imaging direction), and calculates the amount of change in the position of the focal plane based on the amount of change in the tilt angle. Note that the same reference numerals are used for the same functional units as in the first embodiment, and the description thereof will be omitted. Fig. 15 is a configuration diagram showing an example of the functional configuration of the imaging device according to this embodiment.

[0090] The control unit 1002 as a control section is made up of an image capturing direction changing section 103 , a focal position changing section 104 , a sensor angle changing section 105 , and a focal plane changing section 409 .

[0091] The imaging direction change unit 103 acquires an instruction to change the tilt angle (imaging direction change instruction), and instructs the tilt drive unit 106 to change the orientation of the imaging device 1000 by the change amount of the tilt angle. Note that the imaging direction change instruction is the change amount of the tilt angle of the imaging device, and is an amount indicating the angle between the reference plane and the optical axis direction of the imaging device.

[0092] The focal position changing unit 104 calculates the position of the focus lens based on the amount of change in the position of the focal plane acquired from the focal plane changing unit 409, and instructs the focus driving unit 107 to drive the focus lens to the calculated position.

[0093] The sensor angle change unit 105 calculates the elevation angle of the imaging sensor 102 based on the amount of change in the position of the focal plane acquired from the focal plane change unit 409. The sensor angle change unit 105 instructs the sensor drive unit 108 to drive the imaging sensor 102 to achieve the calculated elevation angle.

[0094] The focal plane changing unit 409 receives an instruction to change the tilt angle (imaging direction change instruction) and calculates the amount of change in the position of the focal plane based on the amount of change in the tilt angle. The focal plane changing unit 409 also outputs the calculated amount of change in the position of the focal plane to the focal position changing unit 104 and the sensor angle changing unit 105.

[0095] With the above configuration, as shown in FIG. 16, when the camera height (H) is known and the subject position (L) or the subject height (h) is a known fixed value, the position of the focal plane can be changed according to the change amount of the tilt angle (θ) of the imaging device. That is, since the subject distance (a) can be calculated from L and θ or h and θ, the position and the tilt angle of the focus lens can be calculated. That is, when the subject position is a known fixed value, the height of the focal plane can be changed to the height of the subject according to the change amount of the tilt angle of the imaging device. Also, when the subject height is a known fixed value, the position of the focal plane can be changed to the subject position according to the change amount of the tilt angle of the imaging device.

[0096] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0097] 1001 Optical unit 1002 Control unit 101 Lens 102 Image sensor 103 Imaging direction change unit 104 Focus position change section 105 Sensor angle change unit

Claims

1. a sensor driver that tilts the image sensor with respect to a plane perpendicular to the optical axis of the image pickup optical system; a focus lens driving unit for changing a position of a focus lens in the imaging optical system; A change unit that changes the imaging direction of the imaging means; a control unit that controls a position of the focus lens, the imaging direction, and an angle of the imaging sensor so that a first tilt focus plane and a second tilt focus plane obtained after changing the position of the first tilt focus plane are parallel to each other; The control unit changes the imaging direction so that a distance of the second tilt focus plane included in the imaging range in the direction of the second tilt focus plane is approximately equal to a distance of a range of the first tilt focus plane included in the imaging range in the direction of the first tilt focus plane.

2. 2. The imaging device according to claim 1, wherein the control unit controls a position of the focus lens, the imaging direction, and an angle of the imaging sensor based on a distance between the first and second tilt focus planes.

3. The imaging device according to claim 2 , wherein the control unit calculates an amount of change in the imaging direction based on a distance between the first and second tilt focus planes.

4. 4. The imaging device according to claim 3, wherein the control unit calculates a position of the focus lens based on a distance between the first and second tilt focus planes and the calculated change amount of the imaging direction.

5. 5. The imaging device according to claim 4, wherein the control unit calculates an angle of the imaging sensor based on a distance between the first tilt focus plane and the second tilt focus plane, the calculated change amount of the imaging direction, and the calculated position of the focus lens.

6. The imaging device according to any one of claims 1 to 5, characterized in that the control unit calculates a difference between a distance in the first tilt focus plane direction of the first tilt focus plane included in the imaging range and a distance in the second tilt focus plane direction of a range of the second tilt focus plane included in the imaging range before changing the focus plane from the first tilt focus plane to the second tilt focus plane, and changes the imaging direction when the difference is equal to or greater than a predetermined value.

7. 7. The imaging device according to claim 1, further comprising an instruction unit that instructs a change in the position of the first tilt focus plane.

8. the instruction unit includes a first instruction unit that instructs an amount of change in a position of the focal plane when the focal plane is perpendicular to an optical axis of the imaging optical system, and a second instruction unit that instructs an amount of change in a position of the focal plane when the focal plane is not perpendicular to the optical axis of the imaging optical system, The imaging device according to claim 7, characterized in that, when the focal plane is perpendicular to the optical axis of the imaging optical system, the control unit enables operation of the first indicating unit and restricts operation of the second indicating unit, and when the focal plane is not perpendicular to the optical axis of the imaging optical system, the control unit restricts operation of the first indicating unit and enables operation of the second indicating unit.

9. A control method for an imaging device including a sensor driver that tilts an imaging sensor with respect to a plane perpendicular to an optical axis of an imaging optical system, a focus lens driver that changes a position of a focus lens in the imaging optical system, and a changer that changes an imaging direction of an imaging means, comprising: a control step of controlling a position of the focus lens, the imaging direction, and an angle of the imaging sensor so that a first tilt focus plane and a second tilt focus plane obtained after changing the position of the first tilt focus plane are parallel to each other; A control method for an imaging device, characterized in that, in the control step, the imaging direction is changed so that a distance in the direction of the second tilt focus plane included in the imaging range of the second tilt focus plane is approximately equal to a distance in the direction of the first tilt focus plane of a range included in the imaging range of the first tilt focus plane.

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