CN211606643U

CN211606643U - Automatic focusing device

Info

Publication number: CN211606643U
Application number: CN202020309648.8U
Authority: CN
Inventors: 刘若鹏; 栾琳; 杨亮; 何威
Original assignee: Kuang Chi Institute of Advanced Technology
Current assignee: SHENZHEN KUANG-CHI SUPER MATERIAL TECHNOLOGY Co.,Ltd.
Priority date: 2020-03-12
Filing date: 2020-03-12
Publication date: 2020-09-29
Anticipated expiration: 2030-03-12

Abstract

The utility model discloses an automatic focusing device, this automatic focusing device includes: the shooting equipment is fixed on the base and used for inquiring a focusing distance measuring table under the current magnification, and controlling a focusing motor to adjust the focusing position of the lens according to the focusing stepping number corresponding to the current object distance so that a shot object forms a clear image on an image focal plane; the distance measurement module is used for measuring the current object distance between the optical center of the lens and the shot object; the distance measuring module is fixed on the rotary table, and the rotary table is fixed on the base and used for adjusting the position of the distance measuring module, so that the main optical axis of the distance measuring module is consistent with the main optical axis of the lens in height in the vertical direction, and the main optical axis of the distance measuring module is parallel to the main optical axis of the lens in the horizontal direction. The automatic focusing device can realize the quick focusing of the lens, reduce the conditions of virtual focus and frequent focusing which often appear in the shot picture, ensure that the picture is in a clear state for a long time and improve the quality of the shot picture.

Description

Automatic focusing device

Technical Field

The utility model relates to a video monitoring technical field, more specifically relates to an automatic focusing device.

Background

Under the high-altitude system high-point monitoring scene of a safe city, a variable-focus long-focus pan-tilt camera is required. The core component of the zoom long-focus pan-tilt camera mainly comprises: the mechanical turntable (also called a tripod head) and the variable-focus long-focus integrated machine core can rotate vertically and horizontally in the axial direction. The variable-focus and long-focus integrated machine core can be used for large-magnification optical zoom and focus, and clear imaging of images within and outside several centimeters is achieved. However, in a large-magnification working scene, since the stroke of the focusing motor becomes large, the focusing speed of the variable-focus and long-focus integrated movement is much slower than that of a small-magnification working scene, which causes that the imaging picture of the variable-focus and long-focus integrated movement is easy to blur most of the time and cannot be clearly focused all the time.

SUMMERY OF THE UTILITY MODEL

The utility model provides an automatic focusing device to the above-mentioned problem that exists among the prior art, the focusing speed who has solved the long burnt integrated core that can zoom is slow, leads to the image most of time fuzzy easily, can not the clear problem of focusing of full period.

According to the utility model discloses an aspect provides an automatic focusing device, include:

the shooting equipment is fixed on the base and used for inquiring a focusing distance measuring table under the magnification of the current lens and controlling a focusing motor to adjust the focusing position of the lens according to the focusing stepping number corresponding to the current object distance so that a shot object forms a clear image on an image focal plane;

the distance measurement module is used for measuring the current object distance between the optical center of the lens and the shot object;

the distance measuring module is fixed on the rotary table, and the rotary table is fixed on the base; the turntable is used for adjusting the position of the distance measuring module, so that the height of a main optical axis of the distance measuring module is consistent with that of a main optical axis of the lens in the vertical direction, and the main optical axis of the distance measuring module is parallel to that of the lens in the horizontal direction.

Optionally, the focusing and ranging table is stored in a memory of the shooting device, and a relationship among a magnification factor, an object distance, and a focusing step number is recorded in the focusing and ranging table.

Optionally, the turntable comprises:

the parallelism calibration assembly is used for adjusting the horizontal position of the ranging module, so that the main optical axis of the ranging module is parallel to the main optical axis of the lens in the horizontal direction;

and the height calibration assembly is used for adjusting the vertical position of the ranging module, so that the height of a main optical axis of the ranging module is consistent with that of a main optical axis of the lens in the vertical direction.

Optionally, the parallelism calibration assembly comprises: a parallelism stepping motor, a worm shaft, a turbine and a parallelism rotary table,

the parallelism stepping motor is fixedly connected with the worm shaft, the turbine is fixedly connected with the parallelism rotary table, the worm shaft and the turbine are mutually matched for transmission,

the parallelism stepping motor controls the worm shaft to rotate, the worm shaft drives the turbine to rotate, and then the turbine drives the parallelism rotary table to rotate in the horizontal direction.

Optionally, the parallelism calibration assembly is self-locking in position when the unwinding helix angle of the worm shaft is less than the friction angle of the worm shaft and the turbine wheel contact.

Optionally, the height calibration assembly comprises: the height control mechanism comprises a wedge plate, a height control motor, a pressing plate and a sliding plate, wherein the bottom surface of the wedge plate comprises a plurality of inclined planes, the height control motor comprises a gear reduction box, the sliding plate comprises a plurality of rollers,

the height control motor is fixedly connected with the base, the sliding plate is fixedly connected with the base through the pressing plate, and an output gear of the gear reduction box is in meshing transmission with a sector gear of the sliding plate.

Optionally, the height control motor drives the output gear to rotate, so as to drive the sliding plate to rotate, and in the process of rotating the sliding plate, the plurality of rollers of the sliding plate move along the plurality of inclined surfaces of the wedge plate, so that the wedge plate moves in the vertical direction, and the ranging module moves in the vertical direction.

Optionally, the height calibration assembly is self-locking in position when the inclination angles of the plurality of inclined surfaces of the cam plate are less than the coefficient of friction between the plurality of rollers and the plurality of inclined surfaces.

Optionally, the turntable further comprises: a connecting plate, a plurality of springs and a plurality of fasteners,

the connecting plate is located between the distance measuring module and the parallelism calibrating assembly, the springs are located between the parallelism calibrating assembly and the wedge plate, and the distance measuring module, the connecting plate, the parallelism calibrating assembly, the springs, the height calibrating assembly and the base are fixedly connected through the fasteners.

Optionally, the photographing apparatus includes: a core of the zoom and tele integrated machine;

the ranging module includes: laser rangefinder module.

According to the utility model discloses the automatic focusing device that the embodiment provided, automatic focusing device includes: shooting equipment, range finding module, revolving stage and base. The distance measuring module is fixed on the rotary table, the shooting equipment and the rotary table are fixed on the base, and the rotary table comprises a parallelism calibrating assembly and a height calibrating assembly which have a position self-locking function. In the use process of the automatic focusing device, the horizontal and vertical positions of the distance measuring module can be adjusted through the parallelism calibration assembly and the height calibration assembly, so that the main optical axis of the distance measuring module is parallel to the main optical axis of the lens in the horizontal direction, and the main optical axis of the distance measuring module is consistent with the main optical axis of the lens in the vertical direction, thereby avoiding that the mechanical error caused by the installation of the automatic focusing device is amplified when the lens works in a long-focus mode, and the main optical axis of the distance measuring module is not parallel to or even intersected with the main optical axis of the lens, and further improving the accuracy of the object distance measured by the distance measuring module.

In addition, under the current magnification, when the current object distance measured by the distance measuring module is acquired, the shooting equipment inquires a focusing distance measuring table, and controls a focusing motor to adjust the focusing position of the lens according to the focusing stepping number corresponding to the current object distance so that the shot object forms a clear image on an image focal plane. When the focusing motor moves, the definition characteristic value of the image does not need to be continuously acquired according to a certain focusing evaluation function, the rapid focusing of the lens can be realized, the conditions of virtual focus and frequent focusing which often appear in a shot picture are reduced, the picture is in a clear state for a long time, and the quality of the shot picture is improved.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings.

Fig. 1 shows a control table of a zoom motor and a focus motor of a photographing apparatus according to an embodiment of the present invention.

Fig. 2 shows a schematic structural diagram of an automatic focusing device according to an embodiment of the present invention.

Fig. 3 shows an exploded view of an automatic focusing apparatus according to an embodiment of the present invention.

Fig. 4 shows a schematic structural diagram of a parallelism calibrating assembly according to an embodiment of the present invention.

Fig. 5 shows a schematic structural diagram of a height calibration assembly according to an embodiment of the present invention.

Detailed Description

The invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by like reference numerals. For purposes of clarity, the various features in the drawings are not necessarily to scale. In addition, certain well known components may not be shown.

Numerous specific details of the invention are set forth in the following description in order to provide a more thorough understanding of the invention. However, as will be understood by those skilled in the art, the present invention may be practiced without these specific details.

A lens is a very important component in an image capturing apparatus such as a camera, an Internet Protocol Camera (IPC), and the like. Lenses of current image capturing apparatuses often include a plurality of lenses (concave and convex lenses), that is, imaging is performed by combining a plurality of lenses. In general, a plurality of lenses in a lens for adjusting a focal length are combined into a whole, which is called a zoom group, and the zoom group corresponds to a zoom motor, and the zoom motor adjusts a position of the zoom group, and thus, a magnification. The lenses which play a role in adjusting the image are combined into a whole, called a focus group, and the focus group also corresponds to a focusing motor, and the position of the focus group is adjusted through the focusing motor, so that the focusing position is adjusted.

A zoom motor is an indispensable component in an image photographing apparatus (particularly, a variable-focus image photographing apparatus). A plurality of lenses for changing a focal length in a lens barrel of an image pickup apparatus constitute a lens group called a zoom group, and a position of the lens group is moved by a zoom motor.

The focus motor is also an indispensable component in an image capturing apparatus (particularly a variable focus image capturing apparatus). In a lens barrel of an image pickup apparatus, a plurality of lenses for changing a distance therebetween form a lens group called a focus group, and a position of the lens group is moved by a focus motor.

Shooting equipment, the embodiment of the utility model relates to a shooting equipment is including long burnt all-in-one core of can zooming. The variable-focus all-in-one machine core, such as a 55x variable-focus all-in-one machine core, a 60x variable-focus all-in-one machine core and a 70x variable-focus all-in-one machine core, can be used for large-magnification optical zoom and focusing, and can realize clear imaging of images within and beyond several centimeters.

Fig. 1 shows a control table of a zoom motor and a focus motor of a photographing apparatus according to an embodiment of the present invention. In particular to a control table of a zoom motor and a focusing motor of a 55x zoom and tele integrated machine core. The lens of the 55x zooming and tele all-in-one machine core has the functions of 1x-55x optical zooming, focusing, aperture control and optical filter switching.

It can be seen from the control table shown in fig. 1 that when the lens is at optical magnification 1x and the object distance is changed from 10m to 2m, the difference between the number of steps (focus step number) of the focus motor is 767-; when the lens magnification is at optical magnification 2x (Zoom is 2x), and the object distance is changed from 10m to 2m, the difference of the step number (focus step number) of the focusing motor is 1054 and 1046 is 8 (steps), that is to say, when the lens magnification is at optical magnification 2x (Zoom is 2x), the focusing motor only takes 8 steps at most when the stroke is completed, and a focusing position where a certain point is the best definition of the image can be obtained in the 8 steps; when the lens magnification is 3x (Zoom is 3x), and the object distance is changed from 10m to 2m, the step number (focus step number) of the focusing motor is different 1219-.

When the lens magnification is at the optical magnification 46x (Zoom is 46x), and the object distance is changed from 10m to 2m, the difference between the step number of the focusing motor (focus step number) and 2035 and 1079 is obtained, that is, when the lens magnification is at the optical magnification 46x (Zoom is 46x), the focusing motor will take 1079 steps at most to complete the stroke, and a focusing position where a certain point is the best definition of the image will be obtained in 1079 steps; when the lens magnification is 47x (Zoom is 47x), and the object distance is changed from 10m to 2m, the step number (focus step number) of the focusing motor differs by 2035-; when the lens magnification is 48.8x (Zoom is 48.8x), and the object distance is changed from 10m to 2m, the difference between the number of steps of the focus motor (focus step number) is 2035 and 918 (1117), that is, when the lens magnification is 48.8x (Zoom is 48.8x), the maximum 1117 steps are required for the focus motor to complete the stroke, and a focus position where a certain point is the best definition of the image is obtained in the 1117 steps.

It can be concluded that when the lens is in optical long focus, the focusing motor needs to step more than 1000 steps to find the best focus position of the image than when the lens is in short focus. When the focusing motor moves, the sharpness characteristic value of the image is continuously obtained according to a certain focusing evaluation function (for example, the sharpness characteristic value of the image is obtained according to a certain focusing evaluation function in an image processing module of the shooting device), the focusing motor is controlled according to the sharpness characteristic value, the corresponding focus group is moved through the focusing motor, then the sharpness characteristic value of the image is obtained again at a new position until the sharpness characteristic value meets a certain predetermined condition, and therefore automatic focusing is achieved. In this auto-focusing process, it takes about 1ms for the focus motor to go every step and reacquire the sharpness feature value of the image. When the lens works in a long focus, the number of steps needed by the focusing motor is more than 1000 steps than when the lens works in a short focus, which means that the focusing time is prolonged by more than 1s, and the speed of image focusing is seriously influenced.

The automatic focusing apparatus shown in fig. 2 includes: the photographing apparatus 1000, the ranging module 2000, the turntable 3000, and the base 4000.

A photographing apparatus 1000 comprising: the focusing and ranging system comprises a lens, a focusing motor, a zooming motor and a memory, wherein a focusing and ranging table is stored in the memory, and the relationship among the magnification factor, the object distance and the focusing stepping number is recorded in the focusing and ranging table. The shooting device 1000 is fixed on the base 4000 and used for inquiring a focusing distance measuring table under the current magnification, and controlling a focusing motor to adjust the focusing position of the lens according to the focusing stepping number corresponding to the current object distance so that a shot object forms a clear image on an image focal plane.

The distance measuring module 2000 is, for example, a laser distance measuring module, and is configured to measure a current object distance between an optical center of the lens and the subject.

The turntable 3000 includes: parallelism calibration subassembly 3100 and height calibration subassembly 3200, ranging module 2000 is fixed on revolving stage 3000, and revolving stage 3000 is fixed in on base 4000 for utilize parallelism calibration subassembly 3100 and height calibration subassembly 3200 to adjust ranging module 2000's position, make the primary optical axis of ranging module 3000 highly unanimous with the primary optical axis of camera lens in the vertical direction, the primary optical axis of ranging module 3000 is parallel with the primary optical axis of camera lens in the horizontal direction. The base 4000 of the automatic focusing device can be fixed on a rotating cradle head under a high-altitude high-point monitoring scene, and the rotating cradle head drives the automatic focusing device to rotate so as to realize high-point monitoring.

Fig. 3 shows an exploded view of an automatic focusing apparatus according to an embodiment of the present invention. Fig. 4 shows a schematic structural diagram of a parallelism calibrating assembly according to an embodiment of the present invention. Fig. 5 shows a schematic structural diagram of a height calibration assembly according to an embodiment of the present invention.

The automatic focusing apparatus shown in fig. 3 includes: the photographing apparatus 1000, the ranging module 2000, the turntable 3000, and the base 4000. Wherein, revolving stage 3000 includes: a parallelism alignment assembly 3100, a height alignment assembly 3200, a connecting plate 3300, a plurality of springs 3400, and a plurality of fasteners. As shown in fig. 4, the parallelism calibration assembly 3100 includes: a parallelism stepper motor 3110, a worm shaft 3120, a turbine (not shown), and a parallelism turntable 3130. As shown in fig. 3 and 5, the height calibration assembly 3200 includes: a cam plate 3220, a height control motor 3210, a pressure plate 3230, and a slide plate 3240. The bottom surface of the cam plate 3220 includes a plurality of ramps, the height control motor 3210 includes a gear box, and the slide plate 3240 includes a plurality of rollers. The connection plate 3300 is located between the ranging module 2000 and the parallelism calibration assembly 3100, the plurality of springs 3400 is located between the parallelism calibration assembly 3100 and the wedge plate 3220, and the ranging module 2000, the connection plate 3300, the parallelism calibration assembly 3100, the plurality of springs 3400, the height calibration assembly 3200, and the base 4000 are fixedly connected by a plurality of fasteners.

And the parallelism calibration assembly 3100 is used for adjusting the horizontal position of the ranging module 2000, so that the main optical axis of the ranging module 2000 is parallel to the main optical axis of the lens in the horizontal direction. The parallelism stepping motor 3110 is fixedly connected with the worm shaft 3120, the turbine is fixedly connected with the parallelism rotary table 3130, and the worm shaft 3120 and the turbine are matched with each other for transmission. The parallelism stepper motor 3110 controls the worm shaft 3120 to rotate, the worm shaft 3120 drives the turbine to rotate, and the turbine drives the parallelism turntable 3130 to rotate in the horizontal direction. Parallelism alignment assembly 3100 is self-locking in position when the unwinding pitch angle of worm shaft 3120 is less than the friction angle of the worm shaft 3120 and the turbine wheel contact.

The height calibration assembly 3200 is configured to adjust a vertical position of the distance measuring module 2000, so that a main optical axis of the distance measuring module 2000 is in height correspondence with a main optical axis of the lens in a vertical direction. The height control motor 3210 is fixedly connected with the base 4000, the sliding plate 3240 is fixedly connected with the base 4000 through a pressing plate 3230, and an output gear of the gear reduction box is in meshing transmission with a sector gear of the sliding plate 3240. The height control motor 3210 drives the output gear to rotate, and then drives the sliding plate 3240 to rotate, and in the process of rotating the sliding plate 3240, since the sliding plate 3240 is fixed on the base 4000, a plurality of rollers of the sliding plate 3240 move along a plurality of inclined surfaces of the cam plate 3220, so that the cam plate moves in the vertical direction, and then the distance measuring module 2000 moves in the vertical direction. Height calibration assembly 3200 is positionally self-locking when the slope angle of the plurality of sloped surfaces of cam plate 3220 is less than the coefficient of friction between the plurality of rollers and the plurality of sloped surfaces.

In some optional embodiments of the utility model, can be based on the utility model discloses the automatic focusing device in the embodiment measures range, has seen in the display image of the shooting equipment of automatic focusing device to be the focus clear state, then can be through reading the focus range finding table of storage in the memory, the object distance of the object of being shot in the picture is found back to the focus motor step number two information by current magnification and camera lens.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

In accordance with the embodiments of the present invention as set forth above, these embodiments are not exhaustive and do not limit the invention to the precise embodiments described. The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any person skilled in the art can make various changes, modifications, etc. without departing from the scope of the present invention. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and its various embodiments with various modifications as are suited to the particular use contemplated.

Claims

1. An auto-focusing apparatus, comprising:

2. The autofocus apparatus of claim 1, wherein the focusing and ranging table is stored in a memory of the photographing device, and a relationship among a magnification, an object distance, and a focusing step number is recorded in the focusing and ranging table.

3. The autofocus device of claim 2, wherein the turntable comprises:

4. The autofocus device of claim 3, wherein the parallelism calibration assembly comprises: a parallelism stepping motor, a worm shaft, a turbine and a parallelism rotary table,

5. The autofocus device of claim 4, wherein the parallelism alignment assembly is self-locking in position when the unwinding helix angle of the worm shaft is less than the friction angle of the worm shaft and the worm gear contact.

6. The autofocus device of claim 3, wherein the height calibration assembly comprises: the height control mechanism comprises a wedge plate, a height control motor, a pressing plate and a sliding plate, wherein the bottom surface of the wedge plate comprises a plurality of inclined planes, the height control motor comprises a gear reduction box, the sliding plate comprises a plurality of rollers,

7. The auto-focusing apparatus of claim 6, wherein the height control motor rotates the output gear to rotate the sliding plate, and the plurality of rollers of the sliding plate move along the plurality of inclined surfaces of the cam plate during the rotation of the sliding plate, so that the cam plate moves in a vertical direction, and the distance measuring module moves in a vertical direction.

8. The autofocus device of claim 7, wherein the height calibration assembly is self-locking in position when an inclination of the plurality of inclined surfaces of the cam plate is less than a coefficient of friction between the plurality of rollers and the plurality of inclined surfaces.

9. The autofocus device of claim 8, wherein the turntable further comprises: a connecting plate, a plurality of springs and a plurality of fasteners,

10. The autofocus apparatus of claim 5 or 9, wherein the photographing device comprises: a core of the zoom and tele integrated machine;

the ranging module includes: laser rangefinder module.