CN118625577A - Automatic focus camera and focusing method - Google Patents

Abstract

The present invention discloses an automatic focusing camera and a focusing method. The front and rear positions of the lens of the automatic focusing camera are fixedly arranged at the front end of the camera housing, an imaging module is movably arranged in the camera housing, the imaging module is provided with an imaging chip, the imaging chip is provided with an imaging sensor adapted to the lens, a reciprocating motion device is drivingly connected to the imaging module, and is configured to drive the imaging module to move along the normal of the lens mirror surface, and a focusing controller is control-connected to the reciprocating motion device, and is configured to control the action of the reciprocating motion device to focus the imaging sensor and the lens to achieve clear imaging. The provided camera and focusing method change the focusing structure and focusing mode, reduce the complexity of the camera lens connection structure and the manufacturing cost, avoid the problem of external factors affecting the lens focus, and improve the focusing speed and accuracy.

Description

Automatic focus camera and focusing method

Technical Field

The present invention relates to the technical fields of machine vision, computer vision and video monitoring, and in particular to an automatic focusing camera and a focusing method.

Background Art

The focusing methods of machine vision systems (imaging systems consisting of cameras and lenses) are mainly divided into zoom methods and variable magnification methods. The zoom method mainly achieves clear imaging by manually or electrically adjusting the focal length of the lens, while the variable magnification method mainly achieves clear imaging by adjusting the distance between the entire lens group and the imaging chip.

In current cameras, the imaging module with the imaging chip is fixed inside the camera. After the imaging module is fixed, the front and rear position of the module relative to the lens interface cannot be adjusted. During the focusing process, the focus is mainly achieved through manual adjustment or by driving the lens forward and backward through a motor. In addition, liquid lens zoom is also used to achieve clear imaging of machine vision systems, but the lens connection structure is complex, the cost is high, and the focus control operation is difficult, so it cannot be promoted and applied.

The above-mentioned camera that focuses by moving the lens back and forth has high requirements on the linear motion connection structure between the camera housing and the lens. It must simultaneously meet the requirements of smoothness and sealing of the active linear motion. The lens connection structure is relatively complex and costly. Moreover, during use, the linear motion mechanism connected to the lens is exposed to the outside and is easily affected by factors such as temperature changes and external dust and debris attached to the surface, resulting in uneven movement and inability to move accurately, reducing the focusing speed and accuracy. In addition, the driving structure connected to the lens is easily limited in the diversity of spatial layout.

Summary of the invention

Based on this, the present invention provides an autofocus camera and a focusing method, which change the focusing structure and focusing method, reduce the complexity of the camera lens connection structure and the manufacturing cost, avoid the problem of external factors affecting the lens focus, and improve the focusing speed and accuracy.

In order to achieve the above-mentioned objectives, in a first aspect, the present invention provides an autofocus camera, comprising a camera housing, a rear end of a lens fixedly arranged at a front end of the camera housing, an imaging module movably arranged in the camera housing, the imaging module being provided with an imaging chip, the imaging chip being provided with an imaging sensor adapted to the lens, a reciprocating motion device drivingly connected to the imaging module and configured to drive the imaging module to move along the normal of the lens mirror surface (or the radial surface of the lens interface), and a focus controller controllingly connected to the reciprocating motion device and configured to control the movement of the reciprocating motion device to focus the imaging sensor and the lens to achieve clear imaging.

Furthermore, the reciprocating motion device includes an electric adjustment mechanism, which is configured to drive the imaging module to move along the normal of the lens mirror surface by electric means. The electric adjustment mechanism includes but is not limited to an electromagnetic servo motor, a piezoelectric drive, a voice coil motor, an ultrasonic motor or a linear motor.

Furthermore, the reciprocating motion device also includes a transmission mechanism arranged between the electric adjustment mechanism and the imaging module, and the transmission mechanism includes but is not limited to a ball screw mechanism, a cam mechanism and/or a crank slider mechanism.

Furthermore, the imaging sensor includes but is not limited to a linear array imaging sensor or an area array imaging sensor, and the imaging module is provided with a driving circuit and a data interface integrally connected to the imaging chip.

Furthermore, the camera also includes a first distance detection device, which is configured to detect the object distance from the photographed target to the lens, and the focus controller is signal-connected to the first distance detection device and is configured to receive the detected object distance.

Furthermore, the camera also includes a second distance detection device, which is configured to detect the image distance from the imaging chip to the lens. The focus controller is signal-connected to the second distance detection device and is configured to receive the detected image distance.

Furthermore, an angle adjustment bracket and an angle movement device are provided in the camera housing, the angle adjustment bracket is movably installed in the camera housing through a hinge point, and the lens, imaging module and reciprocating motion device are respectively installed on the angle adjustment bracket; the angle movement device is drivingly connected to the angle adjustment bracket, and is configured to drive the angle adjustment bracket to rotate around the hinge point to adjust the angle of the imaging module and the lens relative to the photographed target.

Furthermore, the camera also includes an angle detection device, which is configured to detect the angle of the photographed target relative to the horizontal plane. The focus controller is signal-connected to the angle detection device and is configured to control the movement of the swing motion device according to the detected angle, and drive the angle adjustment bracket to rotate around the lens to adjust the imaging sensor, the lens and the photographed target to be on the same straight line.

In order to achieve the above object, in a second aspect, the present invention provides a focusing method for an auto-focus camera, which is applicable to the camera, and comprises the steps of:

S50. Fixing the camera outside the photographed object;

S60. The first distance detection device detects the object distance U1 from the photographed target to the lens, and the second distance detection device detects the initial distance V0 from the imaging sensor to the lens;

S70. The focus controller calculates the optimal image distance V1 according to the object distance U1 to meet the conditions for clear imaging:

Among them, U1-object distance, that is, the distance from the object to the lens; V1-image distance, that is, the distance from the imaging sensor to the lens; F-focal length of the lens;

S80. The focus controller calculates the distance that the imaging sensor needs to move ΔV=V1-V0;

S90. The focus controller controls the reciprocating motion device, drives the imaging module to move back and forth, and adjusts the distance from the imaging sensor to the lens to V1 to achieve clear imaging.

Furthermore, the camera also includes an angle adjustment bracket, an angle movement device and an angle detection device.

Before focusing, adjust the angle of the imaging sensor and lens relative to the object being photographed. The steps include:

S10. The camera is fixed outside the photographed object, and the lens and the imaging sensor are arranged on the same horizontal line;

S20. The angle detection device detects the horizontal angle K1 of the photographed target relative to the lens;

S30. The focus controller controls the movement of the swing motion device according to the detected horizontal angle, and drives the angle adjustment bracket to rotate around the lens so that the lens, the imaging sensor and the photographed target are on the same straight line.

Compared with the prior art camera technology that uses the lens to move back and forth to achieve focus, the present invention provides an automatic focus camera technology with the following advantages at least:

First, the provided autofocus camera realizes focusing by moving the imaging module in the camera housing, and structurally, there is no need to consider requirements such as smooth forward and backward reciprocating motion and sealing of the lens, thus simplifying the connection structure between the lens and the camera housing and reducing the manufacturing difficulty and cost of the lens connection structure;

Secondly, during the autofocus process, focusing is achieved by moving the imaging module back and forth in the sealed space of the camera housing, which avoids the problems of motion jamming and inaccurate motion caused by the influence of external temperature and attached dust, and is conducive to improving the speed and accuracy of focusing;

Thirdly, compared with the limited space and layout of the driving structure that drives the lens to move back and forth, the imaging module in the camera housing has higher structural flexibility and more diverse spatial layout, and can better meet the control requirements of the focusing movement process.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

FIG1 is a schematic structural diagram of an auto-focus camera according to an embodiment of the present invention;

FIG2 is a schematic structural diagram of an auto-focus camera according to another embodiment of the present invention;

FIG3 is a flowchart of a method for collinear adjustment according to an embodiment of the present invention;

FIG. 4 is a flowchart of a method for front-to-back distance focusing according to an embodiment of the present invention.

The present disclosure may be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

In the figure, 1-camera housing, 2-lens, 3-imaging module, 4-reciprocating motion device, 5-focus controller, 6-first distance detection device, 7-second distance detection device, 8-angle adjustment bracket, 9-angle motion device, 10-angle detection device, 11-hinge point.

DETAILED DESCRIPTION

Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is not intended to be any limitation on the present disclosure and its application or use. The present disclosure can be implemented in many different forms and is not limited to the embodiments herein.

The words "first", "second" and similar terms used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. "Up", "down", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly. In the present disclosure, when a specific device is described as being between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.

Fig. 1 is a schematic diagram of the structure of an autofocus camera according to an embodiment of the present invention. As shown in Fig. 1, the present invention provides an embodiment of an autofocus camera, comprising a camera housing 1, a rear end position of a lens 2 fixedly arranged at the front end of the camera housing 1, an imaging module 3 movably arranged in the camera housing 1, the imaging module 3 is provided with an imaging chip, and the imaging chip is provided with an imaging sensor adapted to the lens 2; a reciprocating motion device 4 is drivingly connected to the imaging module 3 and is configured to drive the imaging module 3 to move along the normal of the mirror surface of the lens 2; a focus controller 5 is control-connected to the reciprocating motion device 4 and is configured to control the action of the reciprocating motion device 4 to focus the imaging sensor and the lens 2 to achieve clear imaging.

Compared with the cameras in the prior art, the autofocus camera provided by the present invention has a limited space and layout for the driving structure for driving the lens to move back and forth, and does not need to consider the requirements of smooth back and forth reciprocating motion and sealing of the lens in structure, thereby simplifying the connection structure between the lens and the camera housing, reducing the manufacturing difficulty and cost of the lens connection structure. During the autofocus process, focusing is achieved by moving the imaging module back and forth in the sealed space of the camera housing, avoiding the problems of motion jamming and inaccurate motion caused by the influence of external temperature and attached dust, which is conducive to improving the focusing speed and accuracy.

The imaging sensor includes but is not limited to a linear array imaging sensor or a planar array imaging sensor, and the imaging module 3 is provided with a driving circuit and a data interface integrally connected to the imaging chip. In a specific implementation, the focus controller is a single chip microcomputer, an artificial intelligence controller, a control chip, etc. In a specific implementation, the imaging sensor includes visible light, infrared, near infrared, ultraviolet sensors, and polarization sensors, etc.

The reciprocating motion device 4 includes an electric adjustment mechanism, which is configured to drive the imaging module 3 to move along the normal of the mirror surface of the lens 2 by electric means. The electric adjustment mechanism includes but is not limited to an electromagnetic servo motor, a piezoelectric driver, a voice coil motor, an ultrasonic motor or a linear motor. The reciprocating motion device 4 also includes a transmission mechanism arranged between the electric adjustment mechanism and the imaging module 3, and the transmission mechanism includes but is not limited to a ball screw mechanism, a cam mechanism and/or a crank slider mechanism. Thus, the provided autofocus camera achieves focusing by moving the imaging module in the camera housing, and the imaging module in the camera housing is driven to have higher flexibility in structural arrangement and more diverse spatial layout, and can better meet the control requirements of the focusing movement process.

Furthermore, in a specific implementation, the reciprocating motion device further includes a manual adjustment mechanism, which is configured to manually adjust the distance between the imaging module and the lens. Specifically, the manual adjustment mechanism can be a rotating wheel or a lever disposed on the camera housing, and the rotating wheel or the lever is connected to the imaging module through a transmission mechanism such as the ball screw mechanism, the cam mechanism and/or the crank slider mechanism. During the focusing process, the rotating wheel or the lever is manually driven to drive the imaging module to move through the transmission mechanism, thereby achieving precise focusing and improving the focusing speed and accuracy.

In some preferred embodiments, the camera further includes a first distance detection device 6, which is configured to detect the object distance from the photographed target to the lens 2, and the focus controller 5 is connected to the first distance detection device 6 by signal, and is configured to receive the detected object distance. In the specific implementation process, the first distance detection device can be an optical ray distance sensor, and the optical ray can be a laser, infrared ray, etc. The infrared light emitted by the optical ray sensor irradiates the photographed target and is reflected back to detect the distance, thereby realizing the distance measurement from the lens to the detected target, and sending the detected distance value to the focus controller, which uses this value as the object distance as a data basis for further focus adjustment.

Furthermore, the camera also includes a second distance detection device 7, which is configured to detect the image distance from the imaging chip to the lens 2, and the focus controller 5 is connected to the second distance detection device 7 by signal, and is configured to receive the detected image distance. In the specific implementation process, the second distance detection device can be an optical ray distance sensor of the above-mentioned embodiment, or an electronic distance scale, etc., to realize the image distance from the lens to the imaging sensor, which serves as a data basis for further focus adjustment. It should be noted that some servo motors include a second distance detection device 7, and the servo motor can be used to accurately control the movement of the imaging chip.

FIG4 is a flowchart of a method for front-to-back distance focusing according to an embodiment of the present invention. As shown in FIG4 , the present invention accordingly provides a focusing method for an auto-focus camera, which is applicable to the above-mentioned auto-focus camera, and includes the following steps:

S50. Fixing the camera outside the photographed object;

S60. The first distance detection device 6 detects the object distance U1 from the photographed target to the lens 2, and the second distance detection device 7 detects the initial distance V0 from the imaging sensor to the lens 2;

S70. The focus controller 5 calculates the optimal image distance V1 according to the object distance U1 to meet the condition of clear imaging:

Among them, U1-object distance, that is, the distance from the object to the lens 2; V1-image distance, that is, the distance from the imaging sensor to the lens 2; F-focal length of the lens 2;

S80. The focus controller 5 calculates the distance that the imaging sensor needs to move ΔV=V1-V0;

S90. The focus controller 5 controls the reciprocating motion device 4 to drive the imaging module 3 to move back and forth, and adjusts the distance from the imaging sensor to the lens 2 to V1 to achieve clear imaging.

By implementing the above method, focusing can be achieved quickly and automatically. During the focusing process, only the front and rear positions of the imaging module need to be adjusted, and there is no need to adjust the front and rear positions of the lens 2, so that the connection structure of the lens 2 is relatively simple, which correspondingly reduces the manufacturing difficulty and production cost. The imaging module 3 and the reciprocating drive device 4 are both installed inside the camera housing 1, which reduces the influence of factors such as temperature differences and external dust and debris attached to the surface, thereby improving the focusing speed and accuracy.

Based on the above embodiments, the present invention provides an autofocus camera and a focusing method, which change the focusing structure and focusing method, reduce the complexity of the camera lens connection structure and the manufacturing cost, avoid the problem of external factors affecting the lens focus, and improve the focusing speed and accuracy.

The above-mentioned camera that focuses by moving the imaging module back and forth reduces the requirements for the linear motion connection structure between the camera housing and the lens, and there is no need to consider the smoothness and sealing requirements of the linear movement of the lens, so that the lens connection structure is relatively simple, which correspondingly reduces the manufacturing difficulty and production cost. Moreover, during use, the imaging module and the reciprocating drive device are installed inside the camera housing to avoid exposure to the outside, reducing the influence of factors such as temperature changes and external dust and debris attached to the surface. It can achieve smooth and precise movement, improve the focusing speed and accuracy, and easily achieve spatial layout diversity.

FIG2 is a schematic diagram of the structure of an autofocus camera according to another embodiment of the present invention. As shown in FIG2, in some preferred embodiments, an angle adjustment bracket 8 and an angle motion device 9 are provided in the camera housing 1, the angle adjustment bracket 8 is movably installed in the camera housing 1 through a hinge point 11, and the lens 2, the imaging module 3 and the reciprocating motion device 4 are respectively installed on the angle adjustment bracket 8; the angle motion device 9 is connected to the angle adjustment bracket 8 by driving, and is configured to drive the angle adjustment bracket 8 to rotate around the hinge point 11 to adjust the angle of the imaging module 3 and the lens 2 relative to the photographed object. Further, the camera also includes an angle detection device 10, and the angle detection device 10 is configured to detect the angle of the photographed object relative to the horizontal plane. The focus controller 5 is connected to the angle detection device 10 by signal, and is configured to control the movement of the swing motion device according to the detected angle, and drive the angle adjustment bracket 8 to rotate around the lens 2 to adjust the imaging sensor, the lens 2 and the photographed object to the same straight line. The above structure realizes the collinear arrangement of the imaging sensor, the lens to the photographed object, and improves the clarity of the imaging.

FIG3 is a flowchart of a method for collinear adjustment according to an embodiment of the present invention. As shown in FIG3 , based on the above structure, the present invention provides a focusing method for an autofocus camera, wherein the camera further includes an angle adjustment bracket 8, an angle motion device 9 and an angle detection device 10, and is characterized in that:

Before focusing, the angles of the imaging sensor and the lens 2 relative to the object being photographed are adjusted, and the steps include:

S10. The camera is fixed outside the photographed object, and the lens 2 and the imaging sensor are arranged on the same horizontal line;

S20. The angle detection device 10 detects the horizontal angle K1 of the photographed target relative to the lens 2;

S30. The focus controller 5 controls the movement of the swing motion device according to the detected horizontal angle, and drives the angle adjustment bracket 8 to rotate circumferentially around the lens 2 so that the lens 2, the imaging sensor and the photographed object are on the same straight line.

Through the above method, by setting an angle adjustment bracket 8 in the camera housing, the lens 2, imaging module 3 and reciprocating motion device 4 are respectively installed on the angle adjustment bracket 8; the angle detection device detects the horizontal angle of the lens 2, the focus controller 5 receives the above horizontal angle value, and sends a control instruction to the swing motion device, the swing motion device drives the angle adjustment bracket 8 to move, so as to achieve the angle adjustment of the angle adjustment bracket 8 around the hinge point 11 at the lens until the imaging sensor, the lens 2 and the photographed target are located in the same straight line. At this time, the photographed target can map the image to the center of the lens, and further map it to the center of the imaging sensor, which is conducive to clear imaging.

The provided autofocus camera and focusing method are applicable to various types of cameras currently available, including but not limited to near-infrared cameras, far-infrared cameras, visible light cameras, ultraviolet cameras, polarization cameras or color cameras, and have broad application prospects.

So far, various embodiments of the present disclosure have been described in detail. Although some specific embodiments of the present disclosure have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims (10)

1. An auto-focus camera, comprising: Camera housing (1); A lens (2), the rear end of which is fixedly arranged at the front end of the camera housing (1); An imaging module (3) movably arranged in the camera housing (1), the imaging module (3) being provided with an imaging chip, the imaging chip being provided with an imaging sensor adapted to the lens (2); A reciprocating motion device (4) is drivingly connected to the imaging module (3) and is configured to drive the imaging module (3) to move along the normal line of the mirror surface of the lens (2); and A focus controller (5) is connected to the reciprocating motion device (4) and is configured to control the movement of the reciprocating motion device (4) to focus the imaging sensor and the lens (2) to achieve clear imaging. 2. The autofocus camera according to claim 1 is characterized in that the reciprocating motion device (4) includes an electric adjustment mechanism, which is configured to drive the imaging module (3) to move along the normal of the mirror surface of the lens (2) by electric means, and the electric adjustment mechanism includes but is not limited to an electromagnetic servo motor, a piezoelectric drive, a voice coil motor, an ultrasonic motor or a linear motor. 3. The autofocus camera according to claim 2 is characterized in that the reciprocating motion device (4) also includes a transmission mechanism arranged between the electric adjustment mechanism and the imaging module (3), and the transmission mechanism includes but is not limited to a servo motor, a piezoelectric drive, a voice coil motor, an ultrasonic motor or a linear motor. 4. The autofocus camera according to claim 1 is characterized in that the imaging sensor includes but is not limited to a linear array imaging sensor or an area array imaging sensor, and the imaging module (3) is provided with a driving circuit and a data interface integrally connected to the imaging chip. 5. The autofocus camera according to claim 1, 2, 3 or 4, characterized in that the camera further comprises a first distance detection device (6), the first distance detection device (6) being configured to detect the object distance from the photographed target to the lens (2), and the focus controller (5) being connected to the first distance detection device (6) by signal, and being configured to receive the detected object distance. 6. The autofocus camera according to claim 5, characterized in that the camera further comprises a second distance detection device (7), the second distance detection device (7) being configured to detect the image distance from the imaging chip to the lens (2), and the focus controller (5) being connected to the second distance detection device (7) by signal, and being configured to receive the detected image distance. 7. The autofocus camera according to claim 1 is characterized in that an angle adjustment bracket (8) and an angle motion device (9) are provided in the camera housing (1); the angle adjustment bracket (8) is movably installed in the camera housing (1) through a hinge point (11); the lens (2), the imaging module (3) and the reciprocating motion device (4) are respectively installed on the angle adjustment bracket (8); the angle motion device (9) is drivingly connected to the angle adjustment bracket (8) and is configured to drive the angle adjustment bracket (8) to rotate around the hinge point to adjust the angle of the imaging module (3) and the lens (2) relative to the photographed object. 8. The autofocus camera according to claim 7 is characterized in that the camera further comprises an angle detection device (10), the angle detection device (10) is configured to detect the angle of the photographed target relative to the horizontal plane, the focus controller (5) is connected to the angle detection device (10) by signal, and is configured to control the movement of the swing motion device according to the detected angle, and drive the angle adjustment bracket (8) to rotate around the lens (2) to adjust the imaging sensor, the lens (2) and the photographed target to be on the same straight line. 9. A focusing method for an auto-focus camera, applicable to the camera according to claims 1 to 8, characterized in that it comprises the steps of: S50. Fixing the camera outside the photographed object; S60. The first distance detection device (6) detects the object distance U1 from the photographed target to the lens (2), and the second distance detection device (7) detects the initial distance V0 from the imaging sensor to the lens (2); S70. The focus controller (5) calculates the optimal image distance V1 according to the object distance U1 to meet the condition of clear imaging: Wherein, U1 is the object distance, i.e., the distance from the object to the lens (2); V1 is the image distance, i.e., the distance from the imaging sensor to the lens (2); F is the focal length of the lens (2); S80. The focus controller (5) calculates the distance the imaging sensor needs to move ΔV=V1-V0 S90. The focus controller (5) controls the reciprocating motion device (4), drives the imaging module (3) to move back and forth, and adjusts the distance from the imaging sensor to the lens (2) to V1, so as to achieve clear imaging. 10. The focusing method of an auto-focus camera according to claim 9, wherein the camera further comprises an angle adjustment bracket (8), an angle movement device (9) and an angle detection device (10), characterized in that: Before focusing, adjusting the angle of the imaging sensor and the lens (2) relative to the object being photographed includes: S10. The camera is fixed outside the photographed object, and the lens (2) and the imaging sensor are arranged on the same horizontal line; S20. The angle detection device (10) detects the horizontal angle K1 of the photographed object relative to the lens (2); S30. The focus controller (5) controls the movement of the swinging motion device according to the detected horizontal angle, and drives the angle adjustment bracket (8) to rotate circumferentially around the lens (2) so that the lens (2), the imaging sensor and the photographed target are on the same straight line.