JP6705104B2 - Lens device, imaging device, and moving body - Google Patents

Description

The present invention relates to a lens device, an imaging device, and a moving body.

Patent Document 1 discloses a lens driving device including a motor that drives a zoom lens and a motor that drives a focus lens.
Patent Document 1 Utility Model Registration No. 2598758

When a lens such as a focus lens is driven using a gear mechanism, backlash may occur between the gears.

The lens device according to an aspect of the present invention may include a lens. The lens device may include a cam ring that drives the lens in the direction of the optical axis of the lens. The lens device may include a first electric motor and a second electric motor. The lens device may include a first gear driven by a first electric motor. The lens device may include a second gear driven by a second electric motor. The lens device may include a third gear that meshes with the first gear and the second gear to transmit power to the cam ring. In the lens device, one tooth surface of the first tooth of the first gear is in contact with one tooth surface of the third tooth of the third gear and one tooth of the second tooth of the second gear is included. A control unit that controls the rotation of the first electric motor and the second electric motor may be provided so that the surface maintains the first state in which the surface is in contact with the other tooth surface of the third tooth of the third gear.

The controller controls the first gear to rotate when the third gear rotates in the first direction to transmit power to the cam ring, and the third gear rotates to rotate in the second direction to transmit power to the cam ring. The rotation of the first electric motor and the second electric motor may be controlled so as to maintain the state.

The designed electrical characteristics of the first electric motor and the designed electrical characteristics of the second electric motor may be the same. When the third gear rotates in the first direction and transmits power to the cam ring, the control unit causes the second electric motor to supply more electric power to the first electric motor from the power source, and the third gear moves in the second direction. When rotating and transmitting power to the cam ring, the first state may be maintained by causing the second electric motor to supply more electric power from the power source than the first electric motor.

When stopping the third gear rotating in the first direction, the control unit stops the rotation of the first electric motor after stopping the rotation of the second electric motor, and then the third gear rotating in the second direction. When stopping, the rotation of the second electric motor may be stopped after stopping the rotation of the first electric motor.

The control unit controls the rotation of the first electric motor and the second electric motor so as to maintain the first state when the lens driving condition satisfies a predetermined condition, and the lens driving condition satisfies the predetermined condition. When is not satisfied, the rotations of the first electric motor and the second electric motor may be controlled without maintaining the first state.

The control unit may control the rotation of the first electric motor and the second electric motor so as to maintain the first state when the distance for moving the lens in the optical axis direction is equal to or less than a predetermined threshold value.

The first electric motor and the second electric motor may be DC motors.

The cam ring may have a third gear.

The lens may be a focus lens.

When driving the lens in the manual focus mode, the control unit may control the rotation of the first electric motor and the second electric motor so as to maintain the first state.

An imaging device according to an aspect of the present invention may include the above lens device. The image pickup device may include an image pickup unit that picks up light formed by the lens device.

The moving body according to one aspect of the present invention may be a moving body that includes the above-described imaging device and moves.

According to one aspect of the present invention, backlash between gears that occurs when a lens is driven using a gear mechanism can be suppressed.

Note that the above summary of the invention does not enumerate all necessary features of the present invention. Further, a sub-combination of these feature groups can also be an invention.

It is a figure which shows an example of the functional block of the imaging device which concerns on this embodiment. It is a figure which shows an example of the gear structure of a gear part. It is a figure which shows the enlarged view of the part which a 1st gear and a 3rd gear mesh. It is a figure which shows the enlarged view of the part which a 2nd gear and a 3rd gear mesh. It is a figure which shows an example of the relationship between the evaluation value of contrast and the lens position of a focus lens. 9 is a flowchart showing an example of a procedure of switching the operation mode of the focus lens. It is a figure which shows an example of the curve which shows the relationship between a blur amount and a lens position. It is a figure which shows an example of the procedure which calculates the distance to an object based on the amount of blurs. It is a figure for demonstrating the relationship with the position of an object, the position of a lens, and a focal length. It is a figure which shows an example of the curve which shows the relationship between a blur amount and a lens position. 9 is a flowchart showing an example of a procedure of switching the operation mode of the focus lens. It is a figure showing an example of the appearance of an unmanned aerial vehicle and a remote control.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Moreover, not all combinations of the features described in the embodiments are essential to the solving means of the invention.

The claims, the description, the drawings and the abstract contain the subject matter of copyright protection. The copyright owner has no objection to the reproduction by any person of these documents, as it appears in the Patent Office file or record. However, in all other cases, all copyrights are reserved.

FIG. 1 shows an example of functional blocks of the image pickup apparatus 100 according to the present embodiment. The image pickup apparatus 100 includes a lens device 200 and an image pickup section 102.

The image capturing unit 102 includes an image sensor 120, an image capturing control unit 110, a memory 130, and a power supply 140. The lens device 200 includes a plurality of lenses 210, a plurality of lens holding frames 212, a lens control unit 220, a memory 222, a first electric motor 231, a second electric motor 232, a gear unit 240, a cam ring 260, and a detection unit 280.

The image sensor 120 may be composed of CCD or CMOS. The image sensor 120 outputs the image data of the optical image formed via the plurality of lenses 210 to the imaging control unit 110. The imaging control unit 110 may be configured by a microprocessor such as CPU or MPU, a microcontroller such as MCU, or the like. The imaging control unit 110 may control the imaging device 100 according to an operation command of the imaging device 100 via a user's operation unit. The memory 130 may be a computer-readable recording medium and may include at least one of SRAM, DRAM, EPROM, EEPROM, and flash memory such as USB memory. The memory 130 stores programs and the like required by the imaging control unit 110 to control the image sensor 120 and the like. The memory 130 may be provided inside the housing of the imaging device 100. The memory 130 may be provided so as to be removable from the housing of the imaging device 100. The power supply 140 supplies electric power to each of the imaging unit 102 and the lens device 200. The power source 140 may be a battery.

The lens device 200 may be an interchangeable lens that is detachably attached to the imaging unit 102. The lens holding frame 212 holds the lens 210. The pin 214 provided on the lens holding frame 212 is engaged with the cam groove of the cam ring 260. When the cam ring 260 rotates, the pin 214 moves along the cam groove, and the lens 210 moves together with the lens holding frame 212 in the optical axis direction. The plurality of lenses 210 may function as a zoom lens, a varifocal lens, and a focus lens. At least some or all of the plurality of lenses 210 are movably arranged along the optical axis. The image pickup apparatus 100 may include a cam ring for a zoom lens and a cam ring for a focus lens.

The gear unit 240 transmits the power of the first electric motor 231 and the second electric motor 232 to the cam ring 260. The cam ring 260 receives the power transmitted from the first electric motor 231 and the second electric motor 232 via the gear unit 240, and rotates about the optical axis. The first electric motor 231 and the second electric motor 232 may be DC motors. The first electric motor 231 and the second electric motor 232 may be brushed DC motors or brushless DC motors. The designed electrical characteristics of the first electric motor 231 and the designed electrical characteristics of the second electric motor 232 may be the same. The type of the first electric motor 231 and the type of the second electric motor 232 may be the same. That is, the first electric motor 231 and the second electric motor 232 may be of the same type.

The first electric motor 231 and the second electric motor 232 transmit power to the cam ring 260 via the gear portion 240 to rotate the cam ring 260. The detection unit 280 detects the rotation speed of at least one of the first electric motor 231 and the second electric motor 232. The detection unit 280 may include, for example, a photo interrupter.

The lens controller 220 controls the electric power supplied to each of the first electric motor 231 and the second electric motor 232 based on the rotation speed detected by the detector 280. The lens control unit 220 drives the first electric motor 231 and the second electric motor 232 in accordance with the lens control command from the image pickup unit 102 to move the one or more lenses 210 through the gear unit 240 and the cam ring 260 in the optical axis direction. Move along. The lens control command is, for example, a zoom control command and a focus control command. The lens control unit 220 executes at least one of the zoom operation and the focus operation by moving at least one of the lenses 210 along the optical axis.

When operating in the manual focus mode, for example, the lens control unit 220 moves the focus lens along the optical axis according to the operation amount and the operation direction of the operation ring included in the lens device 200 by the user, thereby performing the focus operation. You can do it.

For example, when executing the autofocus operation at the time of shooting a moving image, the lens control unit 220 controls the first electric motor 231 and the second electric motor 232 so as to slightly reciprocally rotate the cam ring 260 in the first direction and the second direction. Control. The lens control unit 220 executes the wobbling operation by slightly reciprocating the focus lens. Here, in the wobbling operation, an evaluation value indicating the degree of image blur such as a contrast value is calculated while slightly vibrating the focus lens along the optical axis, and then a direction to be moved along the optical axis is determined. This is an operation of gradually approaching the focused state. The lens controller 220 is an example of the controller. The lens control unit 220 executes the wobbling operation according to the autofocus command from the imaging unit 102.

The memory 222 stores control values of the plurality of lenses 210. The memory 222 may include at least one of SRAM, DRAM, EPROM, EEPROM, and flash memory such as USB memory.

In order to improve the optical performance, the lens 210 may be required to be upsized. For example, when the lens device 200 is a lens device used in a so-called medium format camera or the like, the lens 210 included in the lens device 200 may increase in size. As described above, when the lens 210 becomes large, the lens 210 may become heavy. For example, in order to slightly reciprocally drive a relatively heavy focus lens by wobbling operation, the electric motor needs to generate a relatively large torque.

When the torque required to drive one or a plurality of large lenses 210 is generated by one electric motor, the electric motor may increase in size. As the electric motor becomes larger, the size of the lens barrel that houses the lens 210 also becomes larger. Therefore, according to the lens device 200 of the present embodiment, the cam ring 260 is driven by using the two first electric motors 231 and 232. As a result, the torque that needs to be generated by one electric motor is suppressed, so that it is possible to suppress the size increase of the electric motor.

Further, when the torque is generated by the two electric motors, the total torque becomes larger than when the torque is generated by the one electric motor. When the torque increases, the reduction ratio of the gear portion 240 can be reduced. That is, it is possible to reduce the number of gears forming the gear unit 240 while suppressing an increase in the size of the electric motor. Energy loss can be suppressed by reducing the number of gears. Further, since the number of gears is reduced, the noise of the gear unit 240 can be reduced. Furthermore, the effect of backlash can be reduced by reducing the number of gears.

As described above, the influence of the backlash can be reduced by driving the cam ring 260 by using the two first electric motors 231 and the second electric motors 232. However, some backlash occurs between the gears. Therefore, in this embodiment, the backlash is further reduced.

FIG. 2A is a diagram showing an example of a gear configuration of the gear unit 240. The gear unit 240 includes a first gear 241 connected to the drive shaft 233 of the first electric motor 231. The gear unit 240 includes a second gear 242 connected to the drive shaft 234 of the second electric motor 232. The first gear 241 and the second gear 242 may be spur gears. The gear unit 240 includes a third gear 270 that meshes with the first gear 241 and the second gear 242. The cam ring 260 may have a third gear 270. The third gear 270 may be provided on the outer peripheral surface of the cam ring 260. The configuration of the gear unit 240 illustrated in FIG. 2A is just an example. The third gear 270 that meshes with the first gear 241 and the second gear 242 may be a two-stage gear. The gear unit 240 may further include at least one gear that transmits the power from the third gear 270 of the two-stage gear to the cam ring 260.

The first gear 241 has a plurality of first teeth 243 on the outer peripheral surface. The first tooth 243 has one tooth surface 244 and the other tooth surface 245 opposite to the one tooth surface 244. The second gear 242 has a plurality of second teeth 247 on the outer peripheral surface. The second tooth 247 has one tooth surface 248 and the other tooth surface 249 opposite to the one tooth surface 248. The third gear 270 has a plurality of third teeth 272 on the outer peripheral surface. The third tooth 272 has one tooth surface 275 and the other tooth surface 274 opposite to the one tooth surface 275.

FIG. 2B is an enlarged view of a portion where the first gear 241 and the third gear 270 are engaged with each other. FIG. 2C is an enlarged view of a portion where the second gear 242 and the third gear 270 are engaged with each other.

The lens control unit 220 controls the rotation of the first electric motor 231 and the second electric motor 232 to control the driving of the gear unit 240 configured as described above. In order to reduce the backlash between the gears, the lens control unit 220 uses one tooth surface 244 of the first tooth 243 of the first gear 241 and one tooth surface 244 of the third tooth 272 of the third gear 270. So as to maintain the first state in which one tooth surface 248 of the second tooth 247 of the second gear 242 is in contact with the other tooth surface 274 of the third tooth 272 of the third gear 270. First, the rotations of the first electric motor 231 and the second electric motor 232 are controlled.

When the third gear 270 rotates in the first direction 250 (counterclockwise) to transmit power to the cam ring 260, the lens control unit 220 determines that the third gear 270 is in the second direction on the side opposite to the first direction 250. In each case of rotating in the direction 254 (clockwise) and transmitting power to the cam ring 260, the rotations of the first electric motor 231 and the second electric motor 232 are controlled so as to maintain the first state. When the lens controller 220 rotates the third gear 270 in the first direction 250 to transmit power to the cam ring 260, the lens controller 220 sets the first electric motor 231 and the second electric motor 232 to the third position so as to maintain the first state. Rotate in direction 252 (clockwise). When the lens controller 220 rotates the third gear 270 in the second direction 254 to transmit the power to the cam ring 260, the lens controller 220 sets the first motor 231 and the second motor 232 to the fourth position so as to maintain the first state. Rotate in direction 256 (counterclockwise).

When the third gear 270 rotates in the first direction 250 and transmits power to the cam ring 260, the lens control unit 220 causes the second electric motor 232 to supply more power to the first electric motor 231 from the power supply 140. Thus, the first state may be maintained. Further, when the third gear 270 rotates in the second direction 254 and transmits power to the cam ring 260, the lens controller 220 supplies more power from the power supply 140 to the second motor 232 from the first motor 231. By doing so, the first state may be maintained.

When stopping the third gear 270 rotating in the first direction 250, the lens controller 220 may stop the rotation of the second electric motor 232 and then the rotation of the first electric motor 231. When stopping the third gear 270 rotating in the second direction 254, the lens controller 220 may stop the rotation of the first electric motor 231 and then stop the rotation of the second electric motor 232.

As described above, the lens control unit 220 controls the rotation of the first electric motor 231 and the second electric motor 232 so as to maintain the first state, so that the third gear 270 moves in the first direction 250 and the second direction. Backlash can be prevented from occurring when each of the 254 starts to rotate.

When the third gear 270 rotates in the first direction 250 and transmits power to the cam ring 260, the lens control unit 220 does not supply power to the second electric motor 232, and only supplies power to the first electric motor 231 from the power supply 140. May be supplied to maintain the first state. When the third gear 270 rotates in the second direction 254 and transmits power to the cam ring 260, the lens controller 220 does not supply power to the first electric motor 231 and supplies power to the first electric motor 232 only from the power supply 140. May be supplied to maintain the first state.

When the third gear 270 rotates in the first direction 250 and transmits power to the cam ring 260, the lens control unit 220 determines that one tooth surface 248 of the second tooth 247 is the other tooth surface of the third tooth 272. The second electric motor 232 is supplied with electric power enough to maintain the state of being in contact with the second electric motor 274, and the first electric motor 231 is supplied with electric power so that the third gear 270 can rotate in the first direction 250 at a desired rotation speed. You may. When the third gear 270 rotates in the second direction 254 and transmits power to the cam ring 260, the lens control unit 220 determines that one tooth surface 244 of the first tooth 243 is one tooth surface of the third tooth 272. Power to the first electric motor 231 enough to maintain contact with the second electric motor 231 and electric power to the second electric motor 232 so that the third gear 270 can rotate in the second direction 254 at a desired rotational speed. You may.

When the lens control unit 220 controls the rotations of the first electric motor 231 and the second electric motor 232 while maintaining the first state, the backlash between the gears is reduced, so that the lens position of the lens 210 can be accurately adjusted. .. On the other hand, since only one of the first electric motor 231 and the second electric motor 232 drives the third gear 270, it is possible to drive the third gear 270 more than the case where both the first electric motor 231 and the second electric motor 232 drive the third gear 270. It is difficult to increase the rotation speed of the third gear 270, and it may take time to move the lens 210. Depending on the driving conditions of the lens 210, it may be preferable to shorten the time for moving the lens 210 rather than the accuracy of the lens position of the lens 210.

Therefore, when the driving condition of the lens 210 satisfies a predetermined condition, the lens control unit 220 controls the rotations of the first electric motor 231 and the second electric motor 232 so as to maintain the first state, and the lens 210 of the lens 210 is controlled. When the driving condition does not satisfy the predetermined condition, the rotations of the first electric motor 231 and the second electric motor 232 are controlled without maintaining the first state. When the driving condition of the lens 210 does not satisfy the predetermined condition, the lens control unit 220 uses the power of both the first electric motor 231 and the second electric motor 232 to drive the third gear via the first gear 241 and the second gear 242. The rotation of the first electric motor 231 and the second electric motor 232 may be controlled to rotate the gear 270.

The lens control unit 220 determines a position control mode that prioritizes the accuracy of the lens position of the lens 210 and a power priority that prioritizes the power to move the lens 210 depending on whether or not the driving condition of the lens 210 satisfies a predetermined condition. You may switch between modes. The lens controller 220 may control the rotation of the first electric motor 231 and the second electric motor 232 in the position control mode so as to maintain the first state. In the power priority mode, the lens controller 220 may control the rotation of the first electric motor 231 and the second electric motor 232 without maintaining the first state. In the power priority mode, the lens control unit 220 causes the first motor 231 to rotate the third gear 270 via the first gear 241 and the second gear 242 with the power of both the first motor 231 and the second motor 232. And the rotation of the second electric motor 232 may be controlled. That is, in the power priority mode, the lens controller 220 simultaneously supplies the same electric power to the first electric motor 231 and the second electric motor 232 to control the rotation of the first electric motor 231 and the second electric motor 232. Good.

In the power priority mode, the lens control unit 220 causes the one tooth surface 244 of the first tooth 243 of the first gear 241 to come into contact with the one tooth surface 275 of the third tooth 272 of the third gear 270, and the second gear 242. While the other tooth surface 249 of the second tooth 247 of the third gear 270 is in contact with the one tooth surface 275 of the third tooth 272 of the third gear 270, the third gear 270 rotates in the first direction 250. The rotation of the electric motor 231 and the second electric motor 232 may be controlled. The lens control unit 220 contacts the other tooth surface 245 of the first tooth 243 of the first gear 241 with the other tooth surface 274 of the third tooth 272 of the third gear 270, and the second tooth 247 of the second gear 242. The first electric motor 231 and the second electric motor 231 are rotated so that the third gear 270 rotates in the second direction 254 while the one tooth surface 248 is in contact with the other tooth surface 274 of the third tooth 272 of the third gear 270. The rotation of the electric motor 232 may be controlled.

Backlash is also preferably reduced when the lens control unit 220 switches from the power priority mode to the position control mode. Therefore, when stopping the third gear 270 rotating in the first direction 250 even in the power priority mode, the lens control unit 220 stops the rotation of the second electric motor 232 and then stops the rotation of the first electric motor 231. Then, when the third gear 270 rotating in the second direction 254 is stopped, the rotation of the second electric motor 232 may be stopped after the rotation of the first electric motor 231 is stopped. Accordingly, the lens control unit 220, when the third gear 270 is stopped, the positional relationship between the first teeth 243 of the first gear 241 and the third teeth 272 of the third gear 270, and the second gear 242. The positional relationship between the second tooth 247 and the third tooth 272 of the third gear 270 can be returned to the first state.

The lens control unit 220 controls the rotation of the first electric motor 231 and the second electric motor 232 so as to maintain the first state when the distance to move the lens 210 in the optical axis direction is equal to or less than a predetermined threshold value. You may. When the distance for moving the lens 210 in the optical axis direction from the current lens position of the lens 210 to the target lens position is less than or equal to a predetermined threshold value, the lens control unit 220 maintains the first state. The rotations of the first electric motor 231 and the second electric motor 232 may be controlled. When driving the lens 210 in the manual focus mode, the lens controller 220 may control the rotation of the first electric motor 231 and the second electric motor 232 so as to maintain the first state.

The lens controller 220 may perform contrast AF in the autofocus mode. In the contrast AF, the lens control unit 220 derives the evaluation value of the contrast of the image captured by the imaging unit 102 while changing the lens position of the lens 210, and the lens position corresponding to the extreme value of the evaluation value of the contrast. The rotations of the first electric motor 231 and the second electric motor 232 may be controlled so as to move the lens 210 first. For example, as shown in FIG. 3, the lens controller 220 rotates the cam ring 260 in one direction to change the lens position of the lens 210 in the order of the lens position P1, the lens position P2, the lens position P3, and the lens position P4. Then, the extreme value of the evaluation value of the contrast is searched for. When the lens position P5 corresponding to the extreme value of the contrast evaluation value is specified, the lens control unit 220 rotates the cam ring 260 in the other direction to move the lens 210 to the lens position P5. In this case, the lens controller 220 may operate in the power priority mode until it can search for the extreme value of the contrast evaluation value, and after operating for the extreme value of the contrast evaluation value, it may operate in the position control mode. As a result, the lens control unit 220 moves the lens 210 at a high speed to search for the extreme value of the contrast evaluation value in a relatively short time, and sets the lens position of the lens 210 to the lens position corresponding to the extreme value. It can be moved accurately.

FIG. 4 is a flowchart showing an example of a procedure for switching the operation mode of the focus lens.

The lens controller 220 sets the focus operation mode to the power priority mode (S100). The lens controller 220 determines whether to operate in the manual focus mode (S102). When operating in the manual focus mode, the lens control unit 220 switches the operation mode to the position control mode and controls the rotations of the first electric motor 231 and the second electric motor 232 (S112).

On the other hand, when operating in the contrast AF mode, the lens controller 220 determines whether or not a subject is selected from the image (S104). The lens controller 220 may determine that the subject is selected when the user selects a desired area on the screen. When the subject is selected, the lens control unit 220 executes contrast AF (S106). The lens control unit 220 controls the rotation of the first electric motor 231 and the second electric motor 232 in the power priority mode to move the focus lens in one direction until the evaluation value of the contrast of the selected area exceeds the extreme value. .. The lens controller 220 determines whether the extreme value of the contrast evaluation value is exceeded (S108). When the contrast evaluation value exceeds the extreme value, the lens control unit 220 switches to the position control mode and maintains the first state in order to move the focus lens to the lens position corresponding to the extreme value of the contrast evaluation value. Thus, the rotations of the first electric motor 231 and the second electric motor 232 are controlled (S110).

According to the above procedure, in contrast AF, the lens position of the focus lens can be adjusted accurately while shortening the time until focusing.

In the autofocus mode, the lens control unit 220, based on the blur amount of a plurality of images captured with the positional relationship between the lens and the imaging surface being different, the lens of the focus lens that focuses on a desired region in the image. It may operate in a position specific mode. This mode is called a blur detection auto focus (BDAF) mode.

For example, the blur amount (Cost) of the image can be expressed by the following equation (1) using the Gaussian function. In Expression (1), x indicates a pixel position in the horizontal direction. σ indicates a standard deviation value.

FIG. 5 shows an example of the curve represented by the equation (1). By focusing the focus lens on the lens position corresponding to the minimum point 502 of the curve 500, the object included in the image I can be focused.

FIG. 6 is a flowchart showing an example of the distance calculation procedure in the BDAF mode. First, in the imaging device 100, the first image I ₁ is captured and stored in the memory 130 in a state where the lens and the imaging surface have the first positional relationship. Next, the image pickup surface of the focus lens or the image sensor 120 is moved in the optical axis direction to bring the lens and the image pickup surface into the second positional relationship, and the image pickup apparatus 100 picks up the second image I ₂ . And stores it in the memory 130 (S10). For example, as in so-called mountain climbing AF, the imaging surface of the focus lens or the image sensor 120 is moved in the optical axis direction so as not to exceed the in-focus point. The amount of movement of the imaging surface of the focus lens or the image sensor 120 may be, for example, 10 μm.

Next, the imaging device 100 divides the image I ₁ into a plurality of areas (S12). The feature amount may be calculated for each pixel in the image I2, and the image I ₁ may be divided into a plurality of regions with a pixel group having similar feature amounts as one region. The pixel group in the range set in the AF processing frame of the image I ₁ may be divided into a plurality of regions. Imaging device 100 divides the image I ₂ into a plurality of regions corresponding to a plurality of areas of the image I _1. The imaging apparatus 100 determines, based on the blur amount of each of the plurality of regions of the image I ₁ and the blur amount of each of the plurality of regions of the image I ₂ , an object included in each of the plurality of regions. The distance to is calculated (S14).

The distance calculation procedure will be further described with reference to FIG. 7. The distance from the lens L (principal point) to the subject 510 (object surface) is A, the distance from the lens L (principal point) to the position (image surface) where the subject 510 forms an image on the imaging surface is B, and the focal length is F. And In this case, the relationship between the distance A, the distance B, and the focal length F can be expressed by the following equation (2) from the lens formula.

The focal length F is specified by the lens position. Therefore, if the distance B at which the object 510 forms an image on the imaging surface can be specified, the distance A from the lens L to the object 510 can be specified using equation (2).

As shown in FIG. 7, the distance B is specified by calculating the position where the subject 510 forms an image from the blur size (confusion circles 512 and 514) of the subject 510 projected on the imaging surface, and further A can be specified. That is, the image forming position can be specified in consideration of the fact that the size of the blur (blur amount) is proportional to the image pickup surface and the image forming position.

Here, the distance from the image I ₁ near the imaging surface to the lens L is D ₁ . The distance from the far image I ₂ from the image plane to the lens L and D _2. Each image is blurred. The point spread function at this time is the PSF, and the images at D ₁ and D ₂ are respectively I _d1 and I _d2 . In this case, for example, the image I ₁ can be expressed by the following expression (3) by a convolution operation.

Further, with the Fourier transform function of the image data I _d1 and I _d2 as f, optical transfer functions (Optical Transfer Function) obtained by Fourier transforming the point spread functions PSF ₁ and PSF ₂ of the images I _d1 and I _d2 are OTF ₁ and OTF. _{As 2} , the ratio is calculated as in the following equation (4).

The value C shown in Expression (4) is the amount of change in the blur amount of each of the images I _d1 and I _d2 , that is, the value C corresponds to the difference between the blur amount of the image I _{d1 and} the blur amount of the image I _d2n. ..

In the BDAF mode, the image capturing apparatus 100 specifies an ideal lens position where a desired area in the image is focused on, based on the blur amount of the image captured at at least two lens positions while moving the lens position of the focus lens. To do. At this time, for example, as shown in FIG. 8, when the distance k between the ideal lens position of the focus lens and the current lens position of the focus lens is relatively long, the lens controller 220 sets the position control mode to the first position. When the rotations of the first motor 231 and the second motor 232 are controlled, it may take a relatively long time to move the lens position of the focus lens to the ideal lens position. Therefore, in the BDAF mode, the lens control unit 220 operates in the power priority mode when the distance k between the ideal lens position of the focus lens and the current lens position of the focus lens is larger than a predetermined threshold value. You may. The lens controller 220 may operate in the position control mode when the distance k is less than or equal to a predetermined threshold.

FIG. 9 is a flowchart showing an example of a procedure for switching the operation mode of the focus lens.

The lens controller 220 sets the focus operation mode to the power priority mode (S200). The lens controller 220 determines whether to operate in the manual focus mode (S202). When operating in the manual focus mode, the lens control unit 220 switches the operation mode to the position control mode and controls the rotation of the first electric motor 231 and the second electric motor 232 (S212).

On the other hand, when operating in the BDAF mode, the lens control unit 220 determines whether or not a subject has been selected from the image (S204). The lens controller 220 may determine that the subject is selected when the user selects a desired area on the screen. When the subject is selected, the lens control unit 220 executes BDAF processing (S206). The lens control unit 220 controls the rotation of the first electric motor 231 and the second electric motor 232 in the power priority mode, and derives the ideal lens position based on the blur amount of the image.

The lens control unit 220 determines whether the distance between the current lens position of the focus lens and the ideal lens position is equal to or less than a predetermined threshold value (S208). The lens control unit 220 controls the rotation of the first electric motor 231 and the second electric motor 232 in the power priority mode until the distance between the lens position of the focus lens and the ideal lens position becomes equal to or less than a predetermined threshold value. (S210).

According to the procedure described above, in BDAF, the lens position of the focus lens can be adjusted accurately while shortening the time until focusing.

The imaging device 100 as described above may be mounted on a moving body. The imaging device 100 may be mounted on an unmanned aerial vehicle (UAV) as shown in FIG. The UAV 10 may include a UAV body 20, a gimbal 50, a plurality of imaging devices 60, and an imaging device 100. The gimbal 50 and the imaging device 100 are an example of an imaging system. The UAV 10 is an example of a moving body propelled by the propulsion unit. The moving body is a concept including a UAV, a flying body such as another aircraft moving in the air, a vehicle moving on the ground, and a ship moving on the water.

The UAV body 20 includes a plurality of rotary blades. The plurality of rotary blades is an example of the propulsion unit. The UAV main body 20 causes the UAV 10 to fly by controlling the rotation of a plurality of rotor blades. The UAV body 20 flies the UAV 10 by using, for example, four rotary wings. The number of rotor blades is not limited to four. Further, the UAV 10 may be a fixed wing aircraft having no rotary wing.

The image capturing apparatus 100 is a camera for capturing an image of a subject included in a desired image capturing range. The gimbal 50 rotatably supports the imaging device 100. The gimbal 50 is an example of a support mechanism. For example, the gimbal 50 supports the imaging device 100 using an actuator so as to be rotatable on the pitch axis. The gimbal 50 further supports the imaging device 100 by using an actuator so as to be rotatable about each of a roll axis and a yaw axis. The gimbal 50 may change the attitude of the imaging device 100 by rotating the imaging device 100 around at least one of the yaw axis, the pitch axis, and the roll axis.

The plurality of imaging devices 60 are sensing cameras that capture images around the UAV 10 in order to control the flight of the UAV 10. Two imaging devices 60 may be provided on the front surface of the UAV 10, which is the nose. Still another two imaging devices 60 may be provided on the bottom surface of the UAV 10. The two imaging devices 60 on the front side may be paired and may function as a so-called stereo camera. The two imaging devices 60 on the bottom side may also be paired and function as a stereo camera. Three-dimensional spatial data around the UAV 10 may be generated based on the images captured by the plurality of imaging devices 60. The number of imaging devices 60 included in the UAV 10 is not limited to four. The UAV 10 only needs to include at least one imaging device 60. The UAV 10 may include at least one imaging device 60 on each of the nose, tail, side surface, bottom surface, and ceiling surface of the UAV 10. The angle of view that can be set by the imaging device 60 may be wider than the angle of view that can be set by the imaging device 100. The imaging device 60 may have a single focus lens or a fisheye lens.

The remote control device 300 communicates with the UAV 10 to remotely control the UAV 10. The remote control device 300 may communicate with the UAV 10 wirelessly. The remote control device 300 transmits instruction information indicating various commands regarding movement of the UAV 10, such as ascending, descending, accelerating, decelerating, moving forward, moving backward, and rotating, to the UAV 10. The instruction information includes, for example, instruction information for increasing the altitude of the UAV 10. The instruction information may indicate the altitude at which the UAV 10 should be located. The UAV 10 moves so as to be located at the altitude indicated by the instruction information received from the remote control device 300. The instruction information may include a lift command for lifting the UAV 10. The UAV 10 rises while receiving the rise command. Even if the UAV 10 receives the ascent command, the UAV 10 may limit the ascent if the altitude of the UAV 10 reaches the upper limit altitude.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is apparent to those skilled in the art that various changes or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

The order of execution of each process such as operations, procedures, steps, and stages in the devices, systems, programs, and methods shown in the claims, the specification, and the drawings is "preceding" and "prior to prior". It should be noted that the output of the previous process can be realized in any order unless it is used in the subsequent process. The operation flow in the claims, the specification, and the drawings is described by using “first,” “next,” and the like for convenience, but it is essential that the operations are performed in this order. Not a thing.

10 UAV
20 UAV main body 50 Gimbal 60 Imaging device 100 Imaging device 102 Imaging unit 110 Imaging control unit 120 Image sensor 130 Memory 140 Power supply 200 Lens device 210 Lens 212 Lens holding frame 214 Pin 220 Lens control unit 222 Memory 231 First electric motor 232 Second electric motor 233, 234 Drive shaft 240 Gear portion 241 First gear 242 Second gear 260 Cam ring 270 Third gear 280 Detection unit 300 Remote operation device

Claims (12)

With a focus lens,
A cam ring that drives the focus lens in the direction of the optical axis of the focus lens;
A first DC motor and a second DC motor;
A first gear driven by the first DC motor;
A second gear driven by the second DC motor;
A third gear that meshes with the first gear and the second gear to transmit power to the cam ring;
When the driving condition of the focus lens satisfies a predetermined condition, one tooth surface of the first tooth of the first gear contacts one tooth surface of the third tooth of the third gear, Also, the first DC motor and the first DC motor and the first DC motor and the first DC motor so as to maintain a first state in which one tooth surface of the second tooth of the second gear is in contact with the other tooth surface of the third tooth of the third gear. A control unit that controls the rotation of the second DC motor ,
The control unit is
When the drive condition of the focus lens does not satisfy the predetermined condition, the rotation of the first DC motor and the second DC motor is controlled without maintaining the first state,
When the focus lens is driven in the manual focus mode, it is determined that the drive condition of the focus lens satisfies the predetermined condition and the first DC motor and the second DC motor are maintained so as to maintain the first state. A lens device that controls the rotation of a motor . The controller controls the case where the third gear rotates in the first direction to transmit power to the cam ring, and the third gear rotates in the second direction to transmit power to the cam ring. The lens device according to claim 1, wherein rotation of each of the first DC motor and the second DC motor is controlled so as to maintain the first state. The designed electrical characteristics of the first DC motor and the designed electrical characteristics of the second DC motor are the same,
When the third gear rotates in the first direction and transmits power to the cam ring, the controller causes the second DC motor to supply more power to the first DC motor from a power source, When the gear rotates in the second direction and transmits the power to the cam ring, the first DC motor causes the second DC motor to supply more electric power from the power source to maintain the first state, The lens device according to claim 1. When stopping the third gear rotating in the first direction, the control unit stops the rotation of the first DC motor after stopping the rotation of the second DC motor and rotates the second gear in the second direction. The lens device according to any one of claims 1 to 3, wherein when stopping the third gear that is present, the rotation of the first DC motor is stopped and then the rotation of the second DC motor is stopped. When the drive condition of the focus lens does not satisfy the predetermined condition, the controller supplies the same electric power to the first DC motor and the second DC motor at the same time without maintaining the first state. it is, to control the rotation of the first 1DC motor and said second 2DC motor, the lens device according to any one of claims 1 4. The control unit controls the rotation of the first DC motor and the second DC motor so as to maintain the first state when the distance for moving the focus lens in the optical axis direction is equal to or less than a predetermined threshold value. The lens device according to any one of claims 1 to 5 . The control unit determines whether or not the distance is equal to or less than the predetermined distance based on a blur amount of an image captured at at least two lens positions while moving the lens position of the focus lens. The lens device according to claim 6 , wherein The control unit, while moving the lens position of the focus lens, determines whether the drive condition of the focus lens satisfies the predetermined condition based on the evaluation value of the image captured at at least two lens positions. It determines, lens device according to any one of claims 1-6. Wherein, when searching the extremum of the evaluation value of the contrast of the image derived in contrast AF, determines that satisfies the driving condition of said focus lens is said predetermined according to claim 8 Lens device. The cam ring has a third gear, a lens device according to any one of claims 1-9. A lens device according to any one of claims 1 10,
An image pickup device, comprising: an image pickup unit that picks up light formed by the lens device. A moving body comprising the image pickup device according to claim 11 .

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