JP2019219597A - Optical device - Google Patents

Abstract

To enable fast focusing without requiring an image sensor suitable for a lens.SOLUTION: An optical device of the present invention comprises: a lens having defined thereon a plurality of lens regions corresponding to distance to an object to be focused on; and a limiting member configured to allow only the rays passing through one of the plurality of lens regions to reach an image sensor, the limiting member capable of changing the lens region for the rays entering the image sensor to pass through.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical device.

Conventionally, in order to focus on a specific subject in an imaging device, a focus lens in the lens is moved along an optical axis, or an image sensor is moved along an optical axis to change a distance from the lens. I have.
In the imaging apparatus 200 shown in FIG. 24, the focus lens 19 between the subject side lens 14 and the image side lens 15 is moved along the optical axis 21 by the focus lens driving unit 26. This makes it possible to focus on the distant subject 16 to obtain a far-in-focus image shown in FIG. 20, focus on the near subject 18 to obtain a near-focus image shown in FIG. To obtain the intermediate in-focus image shown in FIG.
The imaging device 200 shown in FIG. 25 moves the image sensor 13 along the optical axis 21 by the image sensor moving means 27. Thereby, it is possible to focus on the distant subject 16, focus on the intermediate distance subject 17, and focus on the near subject 18.

Non-Patent Document 1 discloses a technique called “Light Field Photography”. According to the present method, it is not necessary to perform image capturing a plurality of times to obtain in-focus images of a plurality of subjects, and it is not necessary to move a lens or a video sensor.
Patent Literature 1 discloses an imaging device including an imaging lens having an area with a long focusing distance (far focusing area) and an area with a short focusing distance (near focusing area), and an imaging element. . The image sensor of Patent Literature 1 has a plurality of light receiving sensors that pupil-divide a light beam that has passed through either a far focusing area or a near focusing area and selectively receive light.

Japanese Patent No. 5647751

Ren Ng, "Digital Light Field Photography", Doctoral Dissertation, Graduate School of Computer Science, Stanford University, July 2006

  However, in the case of an imaging device that moves the focus lens or the image sensor along the optical axis, it takes a predetermined time to focus the image so that the focus lens or the image sensor having a mass is moved. In the technique of Non-Patent Document 1, it is necessary to perform image processing on image data in order to obtain an image focused on a subject after imaging, and it takes a predetermined time to execute the image processing. Further, in the technique of Patent Document 1, an image sensor corresponding to a photographing lens is required.

  The optical apparatus according to the present invention includes a lens in which a plurality of lens areas are determined according to a distance to a subject to be focused, and only light transmitted through any one of the plurality of lens areas is incident on an imaging sensor, and the imaging is performed. A limiting member capable of changing a lens area of the lens through which light incident on the sensor is transmitted.

  According to the present invention, focusing can be performed at high speed without requiring an imaging sensor corresponding to a lens.

FIG. 3 is a diagram illustrating an example of a configuration and the like of an imaging device. FIG. 3 is a diagram illustrating an example of a multifocal lens viewed from an optical axis direction. FIG. 3 is a diagram illustrating an example of a free-form aperture stop as viewed from the optical axis direction. FIG. 3 is a diagram illustrating an example of a free-form aperture stop as viewed from the optical axis direction. FIG. 3 is a diagram illustrating an example of a free-form aperture stop as viewed from the optical axis direction. FIG. 3 is a diagram illustrating an example of a free-form aperture stop as viewed from the optical axis direction. FIG. 3 is a diagram illustrating an example of a multifocal lens viewed from an optical axis direction. FIG. 3 is a diagram illustrating an example of a free-form aperture stop as viewed from the optical axis direction. FIG. 3 is a diagram illustrating an example of a free-form aperture stop as viewed from the optical axis direction. FIG. 3 is a diagram illustrating an example of a free-form aperture stop as viewed from the optical axis direction. FIG. 3 is a diagram illustrating an example of a configuration and the like of an imaging device. FIG. 3 is a diagram illustrating an example of a configuration and the like of an imaging device. FIG. 3 is a diagram illustrating an example of a configuration and the like of an imaging device. FIG. 3 is a diagram illustrating an example of a configuration and the like of an imaging device. FIG. 3 is a perspective view illustrating an example of a configuration of a first lens holding member. FIG. 3 is a diagram illustrating an example of a free-form aperture stop as viewed from the optical axis direction. FIG. 3 is a diagram illustrating an example of a free-form aperture stop as viewed from the optical axis direction. FIG. 3 is a diagram illustrating an example of a configuration and the like of an imaging device. FIG. 3 is a diagram illustrating an example of a configuration and the like of an imaging device. It is a figure showing an example of a captured image. It is a figure showing an example of a captured image. It is a figure showing an example of a captured image. FIG. 3 is a diagram illustrating an example of a free-form aperture stop as viewed from the optical axis direction. FIG. 3 is a diagram illustrating an example of a configuration and the like of an imaging device. FIG. 3 is a diagram illustrating an example of a configuration and the like of an imaging device.

(1st Embodiment)
FIG. 1 is a diagram illustrating an example of a configuration and the like of an imaging device 100 according to the first embodiment. The imaging device 100 includes a subject-side lens 14, a multifocal lens 11a, a free-form aperture stop 12, an image-side lens 15, an image sensor 13, an imaging device control unit 22, and a focus control unit 24. . The imaging device 100 is an example of an optical device.
The image sensor 13 is, for example, a CCD or CMOS image sensor, and outputs a signal corresponding to light incident on the image sensor 13. The image sensor 13 is an example of an image sensor.
The subject side lens 14 is a lens arranged on the subject side.
The image side lens 15 is a lens arranged on the image sensor 13 side.
The imaging apparatus 100 is configured such that the multifocal lens 11a and the free-form aperture stop 12 are removed, and when the imaging apparatus 100 includes the subject-side lens 14, the image-side lens 15, and the image sensor 13, focus is set at infinity. Have been.

The multifocal lens 11a is a lens having uneven power. The power of the lens is a value represented by the reciprocal of the focal length. The multifocal lens 11a is disposed between the subject side lens 14 and the image side lens 15.
The multifocal lens 11a will be described more specifically with reference to FIG. FIG. 2 is a diagram illustrating an example of the multifocal lens 11a viewed from the optical axis 21 direction of the multifocal lens 11a. In the following description, a predetermined direction perpendicular to the optical axis 21 is defined as an X axis as shown in each drawing. In each of the drawings such as FIG. 2, the direction in which the arrow indicating the X axis points is the + X direction (plus X direction), and the opposite direction is the −X direction (minus X direction).
The multifocal lens 11a has the lowest power at the end on the −X direction side (upper end in FIG. 2) and the lower end on the + X direction side (lower end in FIG. 2) when viewed from the optical axis 21 direction. (End) has the highest power. The power of the multifocal lens 11a changes continuously and increases as it proceeds from the end on the −X direction side to the end on the + X direction side. The power of the multifocal lens 11a changes continuously between the position of the first power and the position of the second power which is larger than the first power.

In the multifocal lens 11a, a plurality of lens areas 35 are defined according to the distance to the subject to be focused. FIG. 2 shows three lens regions 35 from a first lens region 35a to a third lens region 35c.
The first lens area 35a is an area including the end on the + X direction side of the multifocal lens 11a. The second lens area 35b is an area including the end on the −X direction side of the multifocal lens 11a. The third lens area 35c is an area between the first lens area 35a and the second lens area 35b. Of the three lens regions 35, the power of the first lens region 35a is the largest, and the power of the second lens region 35b is the smallest.

  Since the power of the multifocal lens 11a is not uniform, the in-focus subject changes according to the lens area 35 of the multifocal lens 11a through which light passes. In the first embodiment, when an image is captured with light transmitted through the first lens area 35a, the closest subject 18 closest to the imaging device 100 among the three subjects illustrated in FIG. 1 is focused. Further, when an image is captured by light transmitted through the second lens area 35b, the far object 16 of the three objects farthest from the imaging device 100 is focused. Further, when an image is captured with light transmitted through the third lens area 35c, the intermediate subject 17 located between the near subject 18 and the far subject 16 is focused.

The free-form aperture stop 12 is arranged on the optical axis 21 of the multifocal lens 11a, closer to the subject than the multifocal lens 11a, and adjacent to the multifocal lens 11a. The free-form aperture stop 12 is arranged on the multifocal lens 11a side with respect to the subject-side lens 14. The free-form aperture stop 12 can change the position, size, shape, and the like of the transmission area 33 and the cut-off area 34 based on the control of the focus control unit 24. The transmission region 33 is a region through which a light beam is transmitted. The blocking region 34 is a region that blocks a light beam without transmitting it. Only the light beam that has passed through the transmission region 33 of the free-form aperture stop 12 enters the multifocal lens 11a. The transmission area 33 is an example of a first area. The blocking area 34 is an example of a second area.
The free-form aperture stop 12 includes a plurality of liquid crystal shutters. More specifically, the free-form aperture stop 12 has a plurality of areas divided into a lattice shape, and a liquid crystal shutter is disposed in each area. The focus control unit 24 controls whether light is transmitted or blocked for each liquid crystal shutter. Through this control, the transmission region 33 of the free-form aperture stop 12 and the position, size, shape, and the like of the transmission region 33 are controlled. The free-form aperture stop 12 advances only the light incident on the transmission area 33 in the direction of the optical axis 21 so that only the light transmitted through any of the plurality of lens areas 35 is incident on the image sensor 13. Since the free-form aperture stop 12 can change the transmission area 33, the lens area 35 of the multifocal lens 11a through which light incident on the image sensor 13 can be changed. The free-form aperture stop 12 is an example of a limiting member.

  The focus control unit 24 corresponds to the transmission area 33 of the free-form aperture stop 12 based on the distance to the subject acquired from the imaging device control unit 22 or the like, with the lens area 35 determined according to the distance to the subject to be focused. Control to make it work. That the transmission region 33 corresponds to the lens region 35 determined according to the distance to the subject to be focused means that only light transmitted through the transmission region 33 enters the lens region 35 determined according to the distance to the subject to be focused. Is satisfied by the transmission region 33. More specifically, when viewed from the direction of the optical axis 21, the transmission region 33 and the lens region 35 determined according to the distance to the subject coincide. The focus control unit 24 includes, for example, a CPU and a storage device that is a storage medium. The CPU of the focus control unit 24 realizes various functions and processes of the focus control unit 24 by executing a program stored in the storage device. The focus control unit 24 may be realized by a dedicated circuit or the like.

With reference to FIGS. 3 to 6, examples of the transmission area 33 and the cutoff area 34 of the free-form aperture stop 12 controlled by the focus control unit 24 will be described. FIGS. 3 to 6 are views each showing an example of the free-form aperture stop 12 as viewed from the optical axis 21 direction.
FIG. 3 shows a state where the entire area of the free-form aperture stop 12 is the transmission area 33 and the cut-off area 34 does not exist.
FIG. 4 shows a state where the first stop area 36 a of the free-form aperture stop 12 is the transmission area 33 and the other is the cut-off area 34. The first stop area 36a is an area on the + X direction side of the free-form aperture stop 12. The transmission region 33 in FIG. 4 corresponds to the first lens region 35a shown in FIG.
FIG. 5 shows a state where the second stop area 36 b of the free-form aperture stop 12 is the transmission area 33 and the other is the cutoff area 34. The second stop area 36b is an area on the −X direction side of the free-form aperture stop 12. The transmission area 33 in FIG. 5 corresponds to the second lens area 35b shown in FIG.
FIG. 6 shows a state in which the third stop area 36 c of the free-form aperture stop 12 is the transmission area 33 and the other is the cut-off area 34. The third stop area 36c is an area at the center of the free-form aperture stop 12 in the X direction. The transmission region 33 in FIG. 6 corresponds to the third lens region 35c shown in FIG.

  The imaging device control unit 22 controls the entire imaging device 100. The imaging device control unit 22 includes, for example, a CPU and a storage device that is a storage medium. The CPU executes the programs stored in the storage device to realize various functions and processes of the imaging device control unit 22. When the imaging device 100 captures an image, the imaging device control unit 22 generates a captured image based on an output signal of the video sensor 13. The imaging device control unit 22 has an image generation unit 23 as a function. The image generation unit 23 generates a captured image based on an output signal of the video sensor 13.

  Next, with reference to FIG. 1, an operation when the image capturing apparatus 100 captures an image will be described. Light emitted from the distant subject 16, the intermediate distance subject 17, and the near subject 18 enters the subject-side lens 14, and then passes through the free-form aperture stop 12, the multifocal lens 11 a, and the image-side lens 15. An image is formed by the sensor 13. At this time, as shown in FIG. 3, when the entire area of the free-form aperture stop 12 is the transmission area 33, an image is formed by light transmitted through all the parts of the multifocal lens 11a having continuous power. Since the image is formed on the sensor 13, all three subjects are blurred images.

  Next, as shown in FIG. 4, under the control of the focus control unit 24, the first stop area 36 a of the free-form aperture stop 12 is the transmission area 33, and the area other than the first stop area 36 a is the cut-off area 34. The imaging in the state described above will be described. In this state, of the light incident on the free-form aperture stop 12, only the light incident on the first stop area 36a passes through the free-form aperture stop 12, and the first lens area 35a of the multifocal lens 11a. Incident on. Then, only the light transmitted through the first lens area 35 a having a large power passes through the image side lens 15 and is imaged by the image sensor 13. As a result, the light emitted from the near subject 18 is focused on the image sensor 13. Therefore, the captured image generated by the image generation unit 23 based on the output signal of the video sensor 13 is an image in which the near subject 18 is focused, as shown in FIG.

  Next, as shown in FIG. 5, under the control of the focus control unit 24, the second stop area 36 b of the free-form aperture stop 12 is the transmission area 33, and the area other than the second stop area 36 b is the blocking area 34. The imaging in the state described above will be described. In this state, of the light incident on the free-form aperture stop 12, only the light incident on the second stop area 36b passes through the free-form aperture stop 12, and the second lens area 35b of the multifocal lens 11a. Incident on. Then, only the light transmitted through the second lens area 35 b having a small power passes through the image side lens 15 and is imaged by the image sensor 13. As a result, the light emitted from the distant subject 16 is brought into focus by the image sensor 13. Therefore, the captured image generated by the image generation unit 23 based on the output signal of the video sensor 13 is an image in which the distant subject 16 is focused, as shown in FIG.

  Next, as shown in FIG. 6, under the control of the focus control unit 24, the third stop area 36c of the free-form aperture stop 12 is the transmission area 33, and the area other than the third stop area 36c is the cutoff area 34. The imaging in the state described above will be described. In this state, of the light that has entered the free-form aperture stop 12, only the light that has entered the third stop area 36c passes through the free-form aperture stop 12, and the third lens area 35c of the multifocal lens 11a. Incident on. Then, only the light transmitted through the third lens region 35c having an intermediate power between the first lens region 35a and the second lens region 35b passes through the image-side lens 15 and is imaged by the image sensor 13. . As a result, the light emitted from the intermediate distance subject 17 is focused on the video sensor 13. Therefore, the captured image generated by the image generating unit 23 based on the output signal of the video sensor 13 is an image focused on the intermediate distance subject 17 as shown in FIG.

  As described above, the imaging apparatus 100 of the first embodiment moves the lens such as the multifocal lens 11a and the image sensor 13 along the optical axis using the free-form aperture stop 12 and the multifocal lens 11a. Without focusing, it is possible to focus on a subject at a desired distance. Further, the imaging apparatus 100 does not need to perform image processing for focusing on a specific subject after imaging. Therefore, the imaging apparatus 100 can focus on the subject at high speed, and can obtain an image focused on the subject at high speed. Also, unlike the technique of Patent Document 1, the imaging device 100 does not need to prepare the image sensor 13 corresponding to the multifocal lens 11a.

Further, the imaging device 100 according to the first embodiment does not move the lens such as the multifocal lens 11a and the image sensor 13 along the optical axis. Therefore, the imaging device 100 does not suffer from abrasion or the like due to the movement of the lens and the image sensor 13, and can ensure durability.
The free-form aperture stop 12 is formed of a liquid crystal shutter. Therefore, the shapes and the like of the transmission area 33 and the cutoff area 34 of the free-form aperture stop 12 can be controlled at high speed.

Further, “Light Field Photography” described in Non-Patent Document 1 is a technique that requires a video sensor having a resolution several times as high as the resolution of an image to be obtained, resulting in an increase in cost. On the other hand, the imaging device 100 according to the first embodiment does not require a video sensor having a resolution several times higher than the resolution of an image, and can suppress an increase in cost.
In the imaging device 100 according to the first embodiment, the free-form aperture stop 12 restricts the transmission region 33 and captures an image using light transmitted only through the lens region 35 having the power required by the multifocal lens 11a. be able to. Therefore, unlike the technique of extending the depth of focus, all the objects are not focused.
In addition, it is possible to quickly focus on objects at various distances. Therefore, it is effective for tracking a plurality of subjects.
In addition, the imaging device 100 according to the first embodiment can shoot an image with a small depth of field without increasing the depth of field. Therefore, the distance to the subject of the imaging device 100 can be measured based on the image captured by the imaging device 100, and the captured image of the imaging device 100 can be used to specify the position of the subject.

(Second embodiment)
Next, an imaging device 100 according to a second embodiment will be described. In the following description of the second embodiment, description of matters common to the above-described first embodiment will be omitted, and matters different from the above-described first embodiment will be described.
The imaging device 100 according to the second embodiment uses a multifocal lens 11b different from the multifocal lens 11a of the imaging device 100 according to the first embodiment. The multifocal lens 11b will be described with reference to FIG. FIG. 7 is a diagram illustrating an example of the multifocal lens 11b viewed from the optical axis 21 direction. The power of the multifocal lens 11b is the smallest at the center point representing the optical axis 21 when the multifocal lens 11b is viewed from the direction of the optical axis 21, and the power continuously increases as the distance from the center point representing the optical axis 21 increases. .
FIG. 7 shows three lens regions 35 from a fourth lens region 35d to a sixth lens region 35f. The fourth lens area 35d is a circular area including the center point of the multifocal lens 11b. The fifth lens area 35e is a ring-shaped outer peripheral area including the outer peripheral edge of the multifocal lens 11b. The sixth lens area 35f is a ring-shaped area between the fourth lens area 35d and the fifth lens area 35e. Of the three lens regions 35, the power of the fourth lens region 35d is the smallest, and the power of the fifth lens region 35e is the largest.

Next, with reference to FIGS. 8 to 10, the transmission region 33 and the cutoff region 34 of the free-form aperture stop 12 according to the second embodiment will be described. 8 to 10 are diagrams each showing an example of the free-form aperture stop 12 viewed from the optical axis 21 direction.
FIG. 8 shows a state in which the fourth stop area 36d of the free-form aperture stop 12 is the transmission area 33 and the area other than the fourth stop area 36d is the cutoff area 34. The fourth stop area 36d is a circular area including the center point, and corresponds to the fourth lens area 35d shown in FIG. In this state, of the light incident on the free-form aperture stop 12, only the light incident on the fourth stop area 36d passes through the free-form aperture stop 12, and the fourth power of the multifocal lens 11b having a small power. The light enters the lens area 35 d and is imaged by the image sensor 13. As a result, the light emitted from the distant subject 16 is focused by the video sensor 13, and a captured image in which the distant subject 16 is focused is generated as shown in FIG.

  FIG. 9 shows a state where the fifth stop area 36 e of the free-form aperture stop 12 is the transmission area 33 and the area other than the fifth stop area 36 e is the cut-off area 34. The fifth stop area 36e is an outer peripheral area including the outer peripheral edge of the free-form aperture stop 12, and corresponds to the fifth lens area 35e shown in FIG. In this state, of the light incident on the free-form aperture stop 12, only the light incident on the fifth stop area 36e passes through the free-form aperture stop 12, and the fifth power of the multifocal lens 11b is large. The light enters the lens area 35 e and is imaged by the image sensor 13. As a result, the light emitted from the near subject 18 is focused by the image sensor 13, and a captured image in which the near subject 18 is focused is generated as shown in FIG.

FIG. 10 shows a state where the sixth stop area 36f of the free-form aperture stop 12 is the transmission area 33 and the area other than the sixth stop area 36f is the cut-off area 34. The sixth stop area 36f is a ring-shaped area between the fourth stop area 36d and the fifth stop area 36e, and corresponds to the sixth lens area 35f shown in FIG. In this state, of the light incident on the free-form aperture stop 12, only the light incident on the sixth stop area 36f passes through the free-form aperture stop 12 and has an intermediate power of the multifocal lens 11b. The light enters the sixth lens area 35f and is imaged by the image sensor 13. As a result, the light emitted from the intermediate distance subject 17 is focused by the video sensor 13, and a captured image in which the intermediate distance subject 17 is focused is generated as shown in FIG.
According to the second embodiment, as in the first embodiment, focusing can be performed at high speed without requiring the image sensor 13 corresponding to the multifocal lens 11b.

(Third and fourth embodiments)
Next, the imaging device 100 according to the third and fourth embodiments will be described. In the following description of the third and fourth embodiments, description of matters common to the above-described first embodiment will be omitted, and matters different from the above-described first embodiment will be described.
The imaging device 100 according to the third embodiment shown in FIG. 11 is different from the imaging device 100 according to the first embodiment shown in FIG. 1 in that the multifocal lens 11a and the free-form aperture stop 12 include the image-side lens 15 and the 13.
The imaging device 100 according to the fourth embodiment illustrated in FIG. 12 differs from the imaging device 100 according to the first embodiment illustrated in FIG. 1 in that the multifocal lens 11a and the free-form aperture stop 12 are closer to the subject than the subject-side lens 14. Is located on the side.
According to the third and fourth embodiments, as in the first embodiment, focusing can be performed at high speed without the need for the image sensor 13 corresponding to the multifocal lens 11a.

(Fifth embodiment)
Next, an imaging device 100 according to a fifth embodiment will be described. In the description of the fifth embodiment described below, description of matters common to the above-described first embodiment will be omitted, and matters different from the above-described first embodiment will be described.
As shown in FIG. 13, in the imaging device 100 according to the fifth embodiment, the free shape aperture stop 12 of the imaging device 100 according to the first embodiment is replaced with a free shape reflection plate 25.

The free-form reflector 25 reflects light incident on the free-form reflector 25. The optical axis 21 is bent 90 ° by the first reflection area of the free-form reflection plate 25 described below. The optical axis before being bent by the first reflection area of the free-form reflector 25 is called a first optical axis 21a, and the optical axis after being bent by the first reflection area of the free-form reflector 25 is called a second optical axis. Of the optical axis 21b.
The free-form reflector 25 includes a plurality of DMDs (Digital Micromirror Devices, digital micromirror devices). More specifically, the free-form reflecting plate 25 has a plurality of regions divided into a lattice shape, and a DMD is arranged in each region. The focus control unit 24 controls the light reflection direction for each DMD.
The free-form reflector 25 is provided with a first reflection area and a second reflection area. The DMD in the first reflection area reflects the incident light toward the multifocal lens 11a. The DMD in the second reflection area reflects the incident light in a direction other than the multifocal lens 11a. Light reflected by the second reflection area does not enter the image sensor 13. The second reflection area is an area other than the second reflection area of the free-form reflection plate 25. The position, size, shape, and the like of the first reflection area and the second reflection area are controlled by the focus control unit 24. The free-form reflector 25 advances only light incident on the first reflection area in the direction of the optical axis 21. Since the free-form reflector 25 can change the first reflection area, it is possible to change the lens area 35 of the multifocal lens 11a through which light incident on the image sensor 13 passes. It is an example of a limiting member. The first reflection area is an example of a first area. The second reflection area is an example of a second area.

  The focus control unit 24 adjusts the first reflection area of the free-form reflector 25 based on the distance to the subject obtained from the imaging device control unit 22 or the like, based on the distance to the subject to be focused. Is controlled to correspond to. The expression that the first reflection area corresponds to the lens area 35 determined according to the distance to the subject to be focused means that only the light reflected by the first reflection area is determined according to the distance to the subject to be focused. Is satisfied by the first reflection region. More specifically, when viewed from the direction of the second optical axis 21b, the first reflection area coincides with the lens area 35 determined according to the distance to the subject.

When focusing on the near subject 18, the first reflection area is provided in the area of the free-form reflection plate 25 corresponding to the first lens area 35a shown in FIG. When focusing on the distant subject 16, the first reflection area is provided in the area of the free-form reflection plate 25 corresponding to the second lens area 35 b under the control of the focus control unit 24. When focusing on the intermediate distance subject 17, the first reflection area is provided in the area of the free-form reflection plate 25 corresponding to the third lens area 35c under the control of the focus control unit 24. Thus, similarly to the first embodiment, an image in which each subject is focused can be generated.
According to the fifth embodiment, as in the first embodiment, focusing can be performed at high speed without the need for the image sensor 13 corresponding to the multifocal lens 11a.

  In the imaging device 100 according to the fifth embodiment, the multifocal lens 11a is arranged on the image sensor 13 along the optical axis 21 rather than the free-form reflector 25. However, the multifocal lens 11a may be disposed closer to the subject than the free-form reflector 25 along the optical axis 21 and may be adjacent to the free-form reflector 25. In other words, the free-form reflecting plate 25 may be arranged along the optical axis 21 closer to the image sensor 13 than the multifocal lens 11a. Also in this case, the focus control unit 24 adjusts the first reflection area of the free-form reflector 25 according to the distance to the subject to be focused, based on the distance to the subject acquired from the imaging device control unit 22 or the like. Control is performed so as to correspond to the determined lens area 35. In this case, the expression that the first reflection area corresponds to the lens area 35 means that the area of the free-form reflection plate 25 on which light transmitted through the lens area 35 is incident becomes the first reflection area. Then, the focus control unit 24 reflects the light incident on the first reflection area at approximately 90 ° on the first reflection area, and the light incident on the first reflection area along the optical axis 21 along the image sensor 13. The DMD of the first reflection area is controlled so as to be incident on the first reflection area. Further, the focus control unit 24 reflects light incident on the second reflection area in a direction different from that of the image sensor 13 in the second reflection area, and transmits light incident on the second reflection area to the image sensor 13. The DMD of the second reflection area is controlled so as not to enter.

(Sixth embodiment)
Next, an imaging device 100 according to a sixth embodiment will be described. In the following description of the sixth embodiment, description of matters common to the above-described first embodiment will be omitted, and matters different from the above-described first embodiment will be described.
As shown in FIG. 14, the imaging device 100 according to the sixth embodiment is different from the imaging device 100 according to the first embodiment in that the subject side lens 14 of the imaging device 100 is replaced with a first lens holding member 50 and the image side lens 15 Is replaced by a second lens holding member 55.

  The first lens holding member 50 holds a wide-angle subject side lens 51 and a telephoto subject side lens 52. The wide-angle object side lens 51 has a wider angle of view than the telephoto object side lens 52. Here, the first lens holding member 50 will be further described with reference to FIG. FIG. 15 is a perspective view showing an example of the configuration of the first lens holding member 50. The wide-angle subject-side lens 51 and the telephoto subject-side lens 52 are respectively mounted on holes provided in the first lens holding member 50. The first lens holding member 50 is provided with a rotation shaft 53. The rotation shaft 53 is provided in parallel with the optical axis 21 as shown in FIG. The rotation of the first lens holding member 50 can be stopped by a mechanism (not shown). The first lens holding member 50 arranges the wide-angle subject-side lens 51 or the telephoto subject-side lens 52 on the light path passing through the optical axis 21 under the control of the imaging device control unit 22 and the like. More specifically, the first lens holding member 50 is fixed such that the center of the wide-angle object side lens 51 or the telephoto object side lens 52 is positioned on the optical axis 21 under the control of the imaging device control unit 22 or the like. .

The second lens holding member 55 holds a wide-angle image side lens 56 and a telephoto image side lens 57. The wide-angle image side lens 56 has a wider angle of view than the telephoto image side lens 57. The configuration of the second lens holding member 55 is the same as that of the first lens holding member 50. The second lens holding member 55 rotates around the rotation axis 58 under the control of the imaging device control unit 22 or the like, so that the wide-angle image side lens 56 or the telephoto image side lens 57 Place. More specifically, the second lens holding member 55 is fixed such that the center of the wide-angle image-side lens 56 or the telephoto image-side lens 57 is positioned on the optical axis 21 under the control of the imaging device control unit 22 and the like. .
The imaging device 100 according to the sixth embodiment includes the first lens holding member 50 and the second lens holding member 55, so that one imaging device can perform imaging at two angles of view, telephoto and wide-angle. It becomes.

In the imaging device 100 according to the sixth embodiment, the focus control unit 24 determines the free-form aperture based on the distance to the subject acquired from the imaging device control unit 22 and the like and the characteristics of the lens arranged on the optical axis 21. The transmission area 33 of the aperture 12 is controlled.
Next, with reference to FIG. 16, the state of the free-form aperture stop 12 when focusing on the intermediate distance subject 17 when the wide-angle subject side lens 51 and the wide-angle image side lens 56 are arranged on the optical axis 21. explain. FIG. 16 is a diagram illustrating an example of the free-form aperture stop 12 viewed from the optical axis 21 direction. When the wide-angle object-side lens 51 and the wide-angle image-side lens 56 are arranged on the optical axis 21, and when focusing on the intermediate distance object 17, the focus control unit 24 controls the seventh stop area 36 g of the free-form aperture stop 12. The free-form aperture stop 12 is controlled so that is a transmission area 33. Then, the free-form aperture stop 12 is controlled so that the area other than the seventh stop area 36 g becomes the cut-off area 34. The lens area 35 of the multifocal lens 11a corresponding to the seventh aperture area 36g has power for focusing on the intermediate distance subject 17 when the wide-angle subject side lens 51 and the wide-angle image side lens 56 are used. Area.

  Next, referring to FIG. 17, the state of the free-form aperture stop 12 when focusing on the intermediate distance subject 17 when the telephoto subject side lens 52 and the telephoto image side lens 57 are arranged on the optical axis 21. explain. FIG. 17 is a diagram illustrating an example of the free-form aperture stop 12 viewed from the optical axis 21 direction. When focusing on the intermediate distance subject 17 when the telephoto subject side lens 52 and the telephoto image side lens 57 are arranged on the optical axis 21, the focus control unit 24 controls the eighth stop area 36 h of the free-form aperture stop 12. The free-form aperture stop 12 is controlled so that is a transmission area 33. Then, the free-form aperture stop 12 is controlled so that the area other than the eighth stop area 36h becomes the cutoff area 34. The lens area 35 of the multifocal lens 11a corresponding to the eighth aperture area 36h has power for focusing on the intermediate distance subject 17 when the telephoto subject side lens 52 and the telephoto image side lens 57 are used. Area.

  As described above, the focus control unit 24 of the sixth embodiment controls the free-form aperture stop 12 according to the characteristics of the lens used. Therefore, in the imaging apparatus 100 according to the sixth embodiment, even when a plurality of lenses having different characteristics are used, it is possible to focus on the subject at high speed, and furthermore, to focus on the image focused on the subject. You can get fast. Further, similarly to the first embodiment, there is no need to prepare the image sensor 13 corresponding to the multifocal lens 11a.

(Seventh and eighth embodiments)
Next, imaging devices 100 according to the seventh and eighth embodiments will be described. In the following description of the seventh and eighth embodiments, description of matters common to the above-described first embodiment will be omitted, and matters different from the above-described first embodiment will be described.
In the imaging apparatus 100 according to the seventh embodiment shown in FIG. 18, the subject side lens 14 has a zoom lens 41, and the subject side lens 14 has a zoom mechanism. The zoom lens 41 is moved along the optical axis 21 by the zoom lens moving means 42 to change the angle of view from the telephoto end to the wide angle end. The zoom lens moving unit 42 moves the zoom lens 41 based on the control of the imaging device control unit 22. In the imaging device 100 according to the seventh embodiment, the focus control unit 24 determines the transmission area 33 of the free-form aperture stop 12 based on the distance to the subject acquired from the imaging device control unit 22 and the state of the zoom lens 41. Control.
Also in the seventh embodiment, as in the sixth embodiment, the transmission area 33 of the free-form aperture stop 12 can be changed with the movement of the zoom lens 41 to focus on any subject. . The focus control unit 24 may store a plurality of patterns representing the position, size, shape, and the like of the transmission region 33 according to the angle of view of the zoom lens 41 and the like. The position, size, shape, and the like of the transmission region 33 may be calculated and obtained. Accordingly, the focus control unit 24 can instantaneously change the focus from the distant subject 16 to the near subject 18 during the zooming of the zoom lens 41, for example.

  In the imaging apparatus 100 according to the eighth embodiment shown in FIG. 19, the image side lens 15 has the zoom lens 43, and the image side lens 15 has a zoom mechanism. The zoom lens 43 is moved along the optical axis 21 by the zoom lens moving means 44 to change the angle of view from the telephoto end to the wide angle end. The zoom lens moving unit 44 moves the zoom lens 43 based on the control of the imaging device control unit 22. In the imaging device 100 according to the eighth embodiment, the focus control unit 24 determines the transmission area 33 of the free-form aperture stop 12 based on the distance to the subject acquired from the imaging device control unit 22 and the state of the zoom lens 43. Control. Also in this case, the focus control unit 24 can instantaneously change the focus from the distant subject 16 to the near subject 18 during the zooming of the zoom lens 43, as in the seventh embodiment.

(Ninth embodiment)
Next, an imaging device 100 according to a ninth embodiment will be described. In the description of the ninth embodiment described below, description of matters common to the above-described first embodiment will be omitted, and matters different from the above-described first embodiment will be described.
The imaging device 100 according to the ninth embodiment can capture a wide dynamic range (hereinafter, referred to as WDR) image. The WDR image is an image in which a dynamic range is artificially enlarged by combining a plurality of images.

  When the illuminance of a distant subject is high, for example, when taking an image from the indoor through a window during daytime when imaging with the imaging apparatus 100, as shown in FIG. Is provided in the second aperture region 36b. In this case, since the illuminance of the distant subject is high, the distant subject may be overexposed in the captured image. Therefore, the focus control unit 24 of the ninth embodiment controls the free-form aperture stop 12 so that the transmission area 33 is smaller when the illuminance of the subject is high than when the illuminance of the subject is low.

In the imaging device 100 according to the ninth embodiment, the focus control unit 24 controls the transmission area 33 of the free-form aperture stop 12 based on the distance to the subject and the illuminance of the subject obtained from the imaging device control unit 22 and the like. I do.
Here, the free-form aperture stop 12 in the case where the illuminance of the distant subject 16 is the first illuminance and the second illuminance higher than the first illuminance will be described with reference to FIGS. FIG. 23 is a diagram illustrating an example of the free-form aperture stop 12 viewed from the optical axis 21 direction.
When the distant subject 16 has the first illuminance, the focus control unit 24 controls the focus control unit 24 so that the transmission area 33 is provided in the second aperture area 36b as shown in FIG.
When the distant subject 16 has the second illuminance, the focus control unit 24 controls the focus control unit 24 so that the transmission area 33 is provided in the ninth aperture area 36i as shown in FIG. The ninth aperture area 36i is an area included in the second aperture area 36b shown in FIG. 5, and has a smaller area than the second aperture area 36b.
As described above, in the imaging device 100 according to the ninth embodiment, the size of the transmission region 33 changes according to the illuminance of the distant subject 16. Therefore, overexposure of the distant subject 16 is prevented, and the distant subject 16 can be clearly seen in the captured image.

Next, an operation of the imaging apparatus 100 in a case where there is a first subject with low illuminance and a second subject with high illuminance at the same distance as the distant subject 16 will be described.
In this case, first, as shown in FIG. 5, the focus control unit 24 controls the free-form aperture stop 12 so that the transmission area 33 is provided in the second stop area 36b. Then, the imaging device control unit 22 controls imaging. Thereby, the first subject is focused, and an image in which the first subject is clearly seen is captured to obtain a first captured image. Further, as shown in FIG. 23, the focus control unit 24 controls the free-form aperture stop 12 so that the transmission area 33 is provided in the ninth stop area 36i. This reduces the amount of light transmitted through the free-form aperture stop 12 as compared with the case where the transmission region 33 is provided in the second stop region 36b. Then, the imaging device control unit 22 controls imaging. As a result, a second captured image in which the second subject is focused and the second subject is clearly seen without overexposure is obtained. Then, similarly to the conventional WDR processing, the imaging device control unit 22 synthesizes the first captured image and the second captured image, so that the first subject and the second subject are clearly captured. A WDR image can be generated.

  Here, an example in which there are two subjects at the same distance as the distant subject 16 has been described, but the number of subjects is not limited to two. Also, when there is a subject having different illuminances at other distances, not at the same distance as the distant subject 16, or when there are a plurality of subjects having different illuminances at different distances, a WDR image can be generated similarly. More specifically, the focus control unit 24 controls the imaging device control unit 22 while controlling the position, size, shape, and the like of the transmission area 33 of the free-form aperture stop 12 according to the distance and illuminance of the subject. Is performed, and the imaging device control unit 22 combines the captured images. As a result, a WDR image in which the subject is clearly captured can be generated.

  In addition, the imaging device 100 having the multifocal lens 11a illustrated in FIG. 2 has been described. However, in the imaging device 100, the multifocal lens 11a illustrated in FIG. 2 may be replaced with the multifocal lens 11b illustrated in FIG. Even in this case, the focus control unit 24 performs imaging while controlling the position, size, shape, and the like of the transmission area 33 of the free-form aperture stop 12 according to the distance and illuminance of the subject. Then, the imaging device control unit 22 combines the captured images to generate a WDR image in which the subject is clearly captured.

Conventionally, a WDR image is obtained by combining images continuously photographed at a plurality of different shutter speeds. However, conventionally, since it takes time to move the focus, it has been difficult to acquire a WDR image by focusing on a plurality of subjects at different distances. On the other hand, according to the imaging device 100 of the ninth embodiment, it is possible to acquire WDR images focused on a plurality of subjects at different distances.
According to the ninth embodiment, as in the first embodiment, focusing can be performed at high speed without the need for the image sensor 13 corresponding to the multifocal lens 11a.

(Modification)
The imaging device 100 of each of the above embodiments may be a monitoring camera. Since the imaging device 100 can focus on objects at various distances at high speed, it can be effectively used as a surveillance camera.
Further, the imaging device control unit 22 may have the function of the focus control unit 24. In each of the above embodiments, the multifocal lens 11b shown in FIG. 7 may be used instead of the multifocal lens 11a. In the imaging device 100 having the free-form aperture stop 12 of each of the above embodiments, the free-form aperture stop 12 may be replaced with the free-form reflector 25 as described in the fifth embodiment.

  In the imaging apparatus 100 according to the embodiment having the above-described multifocal lens 11a or 11b, the free-form aperture stop 12 is disposed closer to the subject than the multifocal lens 11a or 11b. However, the free-form aperture stop 12 may be disposed closer to the image sensor 13 than the multifocal lens 11a or 11b, and may be adjacent to the multifocal lens 11a or 11b. Also in this case, the focus control unit 24 sets the transmission area 33 of the free-form aperture stop 12 based on the distance to the subject obtained from the imaging device control unit 22 or the like to a lens determined according to the distance to the subject to be focused. Control is performed so as to correspond to the area 35. In this case, that the transmission area 33 corresponds to the lens area 35 means that the area of the free-form aperture stop 12 where the light transmitted through the lens area 35 determined according to the distance to the subject to be focused enters the transmission area 33. That is.

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

  As described above, the present invention has been described with the embodiment. However, the above embodiment is merely an example of the embodiment in carrying out the present invention, and the technical scope of the present invention is interpreted in a limited manner. It must not be. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features. Further, the above embodiments and modifications may be arbitrarily combined.

  As described above, according to the above-described embodiment, focusing can be performed at high speed without requiring an imaging sensor corresponding to a lens.

REFERENCE SIGNS LIST 100 imaging device 11a multifocal lens 11b multifocal lens 12 free-form aperture stop 13 image sensor 14 subject-side lens 15 image-side lens 22 imaging device controller 24 focus controller

Claims (13)

A lens in which a plurality of lens areas are determined according to a distance to a subject to be focused;
Limiting member capable of changing only the light transmitted through any of the plurality of lens areas to the image sensor, and changing the lens area of the lens through which the light incident on the image sensor is transmitted,
An optical device having:   The restriction member is disposed on the optical axis of the lens, has a first region that can be changed, and a second region other than the first region, and restricts only light incident on the first region. The optical device according to claim 1, wherein only light transmitted through any of the plurality of lens regions is incident on the image sensor by advancing in a direction of an optical axis of the lens.   The optical device according to claim 2, wherein the restricting member has a plurality of liquid crystal shutters, and the liquid crystal shutter in the first area transmits light, and the liquid crystal shutter in the second area blocks light.   The optical device according to claim 2, wherein the restricting member is disposed closer to a subject than the lens, and light transmitted through the first region is incident on the lens.   The restricting member reflects the light incident on the first area in the direction of the lens, folds the optical axis of the lens, and directs the light incident on the second area in a direction different from the direction of the lens. The optical device according to claim 2, which reflects light.   The restriction member has a plurality of digital micromirror devices, the first area of digital micromirror devices reflects light in the direction of the lens, and the second area of digital micromirror devices of the lens. 6. The optical device according to claim 5, wherein the light is reflected in a direction different from the direction.   The optical device according to claim 2, further comprising a control unit configured to control a position and a size of the first area based on a distance to a subject to be focused.   The optical device according to claim 7, wherein the control unit controls a position and a size of the first area based on a distance to a subject to be focused and illuminance of the subject.   9. The optical device according to claim 7, wherein the control unit controls the first area to be smaller when the illuminance of the subject is the second illuminance higher than the first illuminance than when the illuminance of the subject is the first illuminance. 10. apparatus.   The control unit controls a position and a size of the first area based on a distance to a subject to be focused and characteristics of a lens disposed on an optical axis of the lens. 10. The optical device according to any one of claims 9 to 10. A lens holding member that holds a plurality of other lenses at positions different from the lens,
The optical device according to claim 1, wherein the lens holding member arranges any one of the plurality of other lenses on an optical axis of the lens.   The optical device according to any one of claims 1 to 11, wherein the power of the lens continuously changes between a position of a first power and a position of a second power larger than the first power. The image sensor;
Generating means for generating an image based on an output signal of the image sensor,
The optical device according to claim 1, further comprising: