KR20140007713A - Camera module and method for controlling thereof - Google Patents

Abstract

A camera module and a method for controlling the camera module are provided. The camera module comprises: a lens unit including a focus lens; a lens driving unit which drives the lens unit; an imaging unit which generates an image signal by imaging a light passed through the lens unit; a frequency information detecting unit which detects the frequency information of the image from the image signals generated for each position of the focus lens; a shake detecting unit which generates a shake detection information by sensing the shaking; and a control unit which conducts an auto focusing, which is to find an optimal focal length of the focusing lens, by comparing the frequency information of the image according to the position shift of the focus lens, and deactivates the auto focusing when the shake detection information is received. [Reference numerals] (AA,CC,FF) No; (BB,DD,EE) Yes; (S110) AF start; (S120) Moving lens reference position; (S130) Detecting image frequency information; (S140) Determining optimum focus distance?; (S150) Moving the lens to the optimum position; (S160) AF termination; (S170) Checking shake detection; (S180) Shake is generated?; (S200) Moving the lens

Description

Camera module and its control method {CAMERA MODULE AND METHOD FOR CONTROLLING THEREOF}

The present invention relates to a camera module and a control method thereof.

In recent years, the camera supports Auto Focusing (AF), a function that automatically adjusts the focus. A camera having an auto focusing function determines the optimal focal length by moving the lens at a predetermined distance from the reference position of the lens and repeatedly detecting the high frequency components of the image generated by the image pickup unit. use.

However, a camera that does not detect a shake of the camera itself may obtain an incorrect focus value due to a blur phenomenon of the imaging unit when a shake occurs during auto focusing.

In addition, when the auto focusing is performed continuously, the auto focusing may be performed while the camera shakes. Therefore, the effect of auto focusing is reduced and unnecessary auto focusing is performed to increase power consumption.

Korean Patent Publication No. 10-2008-0098712

In order to solve the above problems of the prior art, the present invention provides a camera module and a control method for stopping auto focusing when the shaking occurs to effectively perform autofocusing, and resumes the auto focusing when the shaking stops.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood from the following description.

In order to achieve the above object, the camera module according to an aspect of the present invention includes a lens unit including a focus lens, a lens driving unit for driving the lens unit, an imaging unit for imaging the light passing through the lens unit to generate an image signal, the focus lens A focus lens by comparing a frequency information detector for detecting image frequency information from image signals generated for each position of the camera, a shake detector for detecting shake to generate shake detection information, and image frequency information detected according to a positional movement of the focus lens And a controller for performing auto focusing to find an optimal focal length and stopping auto focusing when receiving shake detection information.

In order to achieve the above object, a control method of a camera module for performing auto focusing according to another aspect of the present invention includes the steps of moving the focus lens to a reference position to perform auto focusing, generating an image signal and generating an image from the image signal. Detecting the frequency information, checking the high frequency component from the image frequency information to determine the optimum focal length, detecting the shaking to stop the auto focusing, and checking the stopping of the shaking to move the focus lens Resuming performance of focusing.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It is provided to fully inform the owner of the scope of the invention.

The camera module and its control method according to an embodiment of the present invention can stop auto focusing if a shake occurs while performing auto focusing, and resume auto focusing when the shake stops.

In the camera module and its control method according to an embodiment of the present invention, since the image frequency information obtained by performing auto focusing during shaking may be inaccurate, wait until the shaking stops and then resume auto focusing to efficiently perform auto focusing. Can be.

1 is a block diagram illustrating a camera module according to an exemplary embodiment of the present invention.
2 is a diagram illustrating a focus window set in a camera module according to an embodiment of the present invention.
3 is a view illustrating movement of a focus lens of a camera module according to an exemplary embodiment of the present invention.
4 is a view showing a control method of a camera module according to an embodiment of the present invention.

While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and similarities.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram illustrating a camera module according to an exemplary embodiment of the present invention.

1, the camera module 100 according to an embodiment of the present invention includes a lens unit 110, a lens driver 120, an imaging unit 130, a frequency information detector 140, and a shake detection unit 150. ), The storage unit 160 and the control unit 170.

The lens unit 110 collects the light reflecting the subject 50, and causes the image pickup unit 130 to form an image. To this end, the lens unit 110 may be configured as an optical system with a plurality of lenses, and the lenses may form an optical group for each function. Here, the lens unit 110 may include a focus lens 115 to perform focus adjustment.

The focus lens 115 is adjusted in position to adjust the focus on the subject 50. Here, the focus lens 115 can be adjusted in position by the lens driving unit 120.

The image sensing unit 130 senses light passing through the lens unit 110 and generates an image signal for the image of the subject 50. The image capturing unit 130 may include an image capturing unit for photographing an image of the subject 50. The imaging unit may be configured by a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) method. The imaging unit 130 may provide the generated image signal to the frequency information detection unit 140 or the control unit 170.

The frequency information detector 140 detects frequency information of an image signal. Here, the frequency information detector 140 may include a filter for detecting a frequency component of an image signal. For example, the frequency information detector 140 may include a band pass filter implemented using a low pass filter or a high pass filter. The frequency information detector 140 detects a frequency component of the image signal and converts the complexity of the image into a numerical value.

The shake detection unit 150 detects shake of the camera module 100. In addition, the shake detection unit 150 detects a shake to generate shake detection information. The shake detection unit 150 may include an angular velocity sensor such as a gyro sensor. The angular velocity sensor may detect the shaking of the camera module 100 by measuring the angular velocity corresponding to the angular displacement per unit time.

In addition, the shake detection unit 150 generates shake stop information when there is no shake. The shake detection unit 150 may generate shake stop information when there is no change in the angular velocity.

The shake detection unit 150 may provide shake detection information or shake stop information to the controller 170.

The storage unit 160 stores the detected image frequency information corresponding to the focal length of the lens unit 110.

The control unit 170 controls the lens driving unit 120 to perform autofocusing. Here, the controller 170 may control the lens driver 120 to move the focus lens 115 to adjust the focal distance.

The control unit 170 controls the lens driving unit 120 to move the focus lens 115 from the minimum focal distance to the maximum focal distance. For example, the controller 170 may control the lens driver 120 by setting an initial lens movement direction such that the focus lens 115 moves from a distance to a near distance.

In addition, the controller 170 may receive image frequency information corresponding to each focal length from the frequency information detector 140. The controller 170 may determine, as the optimal focal length, the point where the high frequency component is the largest from the received image frequency information.

In addition, the controller 170 receives the shake detection information from the shake detection unit 150. In particular, the controller 170 may stop auto focusing when the shake detection information is received. The controller 170 may stop the movement of the focal length of the focus lens 115 by controlling the lens driver 120.

In addition, the controller 170 may determine the change of focus after receiving the shake detection information. Herein, the controller 170 controls the angle of view of the lens unit 110, the ratio of the af window 320 in the image 310 as captured in FIG. 2, and the shake detection unit 150. The change of focus can be determined by calculating the measured rotation angle. For example, the controller 170 may compare the focus window 320 set for auto focusing before and after occurrence of movement, and determine that the focus of the lens unit 110 is changed when the overlapping area of the focus window 320 is small. .

In addition, the controller 170 may resume auto focusing when the shaking stop information is received. In this case, the controller 170 may control the lens driver 120 to resume the focal length movement of the focus lens 115.

In detail, when a shake is detected in the process of moving the focus lens 115 in the initial lens movement direction, and the controller 170 stops auto focusing, the controller 170 checks the high frequency component included in the image frequency information to optimize You can resume autofocusing to find the focal length. Herein, the controller 170 resumes auto focusing with reference to FIG. 3.

3 is a view illustrating movement of a focus lens of a camera module according to an exemplary embodiment of the present invention.

The controller 170 may stop auto focusing after detecting shaking, and then resume auto focusing to find an optimum focal length from the current position of the focus lens 115 when the focus change is small.

For example, the controller 170 moves the focus lens 115 from the current position of the focus lens 115 to the first critical position in the distant direction if the high frequency components detected along the initial lens movement direction are increasing and decreasing. Auto focusing can be resumed to find the optimum focal length. Alternatively, if the detected high frequency components continue to increase along the initial lens movement direction, the controller 170 moves the focus lens 115 from the current position of the focus lens 115 to the second critical position in the near direction to provide an optimal focus. Auto focusing to find the distance can be resumed. Alternatively, if the detected high frequency components continue to decrease along the initial lens movement direction, the controller 170 moves the focus lens 115 from the current position of the focus lens 115 to the first critical position in the distant direction, thereby optimizing the optimal focus. Auto focusing to find the distance can be resumed.

In addition, the controller 170 may stop auto focusing after the shaking is detected, and then resume auto focusing to find the optimum focal length from the initial position of the focus lens 115 when the focus change is large. Here, the initial position of the focus lens 115 may be set within a minimum focal length and a maximum focal length in order to quickly and efficiently perform auto focusing.

The camera module according to an embodiment of the present invention may stop auto focusing if the shaking occurs while performing auto focusing, and resume auto focusing when the shaking stops. Since the camera module according to an embodiment of the present invention may have incorrect image frequency information obtained by performing auto focusing during shaking, the camera module may wait until the shaking stops and resume auto focusing to efficiently perform auto focusing.

4 is a view showing a control method of a camera module according to an embodiment of the present invention.

Referring to FIG. 4, in the method of controlling a camera module according to an embodiment of the present disclosure, starting auto focusing to find an optimal focal length for a subject (S110) and moving a focus lens to a reference position (S120). ), Generating an image signal for the subject and detecting image frequency information from the image signal (S130), determining an optimum focal length by checking a high frequency component from the image frequency information (S140), and checking shaking detection. In operation S170, it may be determined whether the shaking is continued (S180), and resuming auto focusing (S190).

Here, the control method of the camera module according to an embodiment of the present invention will be described in detail with reference to the camera module shown in FIG. 1.

In step S110, the controller of the camera module starts auto focusing to find an optimal focal length for the subject.

In step S120, the control unit of the camera module controls the lens driving unit to move the focus lens of the lens unit to the reference position. The reference position may be a position of a focus lens that is preset in order to find an optimal focal length. For example, when auto focusing is resumed after the shaking is eliminated, the reference position may be the current position or the initial position of the focus lens.

In operation S130, the image capturing unit of the camera module captures light passing through the focus lens to generate an image signal. In operation S130, the frequency information detection unit of the camera module detects the image frequency information from the generated image signal.

In operation S140, the controller determines whether the optimal focal length is based on the detected image frequency information. Here, the controller may check whether the high frequency component included in the detected image frequency information is the largest in order to determine whether it is an optimal focal length. To this end, the controller may retrieve the high frequency components of the image frequency information previously stored in the storage unit according to the positional movement of the focus lens and compare them with the high frequency components included in the detected image frequency information. The controller may determine an optimal position of the focus lens for focusing on the subject as a result of the comparison.

If the controller finds the optimum focal length in step S140, the control moves to step S150. Alternatively, if the controller does not find an optimal focal length in step S140, the control moves to step S170.

In step S150, the controller controls the lens driver to move the focus lens to an optimal position.

Next, in step S160, since the control unit has found the optimum focal length, auto focusing is terminated.

In step S170, the control unit of the camera module does not find the optimum focal length, so it checks the detection of the shake before moving the focus lens. Here, the controller may receive the shake detection information or the shake stop information from the shake detection unit composed of the angular velocity sensor. The controller stops auto focusing when receiving the shake detection information.

In operation S180, the controller of the camera module determines whether shaking is continued. The controller checks the information received from the shake detection unit and determines whether the shake is continued. When the shaking detection information is received, the controller determines that the shaking is continued and stops auto focusing.

Or, if the shaking stop information is received, the controller determines that the shaking has stopped and moves to step S190 to resume auto focusing.

In step S190, the controller of the camera module resumes auto focusing. Here, the controller may control the lens driver to find the optimum focal length when there is no shaking. The controller controls the lens driver to move the focus lens in the set lens moving direction.

Alternatively, when the shaking stops, the controller checks the focus change and moves the focus lens to the reference position. The controller may determine the focus change by calculating a ratio of the angle of view of the lens unit and the focus window and the rotation angle measured by the shake detection unit. If the focus change is small and the focus change is small, the controller may resume auto focusing by moving the focus lens from the current position of the focus lens to the set lens moving direction. In addition, when the focus change is large, the controller may resume auto focusing by moving the focus lens from the initial position of the focus lens in the set lens moving direction.

The controller may repeat the above process until auto focusing is resumed to find an optimum focal length.

The control method of the camera module according to an embodiment of the present invention can improve auto focusing by stopping auto focusing when shaking occurs while performing auto focusing, and resuming auto focusing when shaking is stopped. In addition, the control method of the camera module according to an embodiment of the present invention can increase the accuracy of determining the occurrence and stop of shaking when performing auto focusing continuously.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention.

Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments.

The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims (9)

A camera module for performing autofocusing,
A lens unit including a focus lens;
A lens driving unit for driving the lens unit;
An imaging unit for imaging the light passing through the lens unit to generate an image signal;
A frequency information detector for detecting image frequency information from an image signal generated for each position of the focus lens;
A shake detection unit for detecting shake to generate shake detection information; And
And a controller configured to compare the image frequency information detected according to the positional movement of the focus lens to perform auto focusing to find an optimal focal length of the focus lens, and to stop the auto focusing when receiving the shake detection information. Camera module.
The method according to claim 1,
The shake detection unit is a camera module, characterized in that for generating no shaking stop information when there is no shaking.
The method of claim 2,
And the control unit receives the shake stop information and resumes performing the auto focusing.
The method of claim 3,
And the control unit resumes performing the auto focusing at the current position or the initial position of the focus lens.
The method according to claim 1,
The controller may be configured to set a partial region as a window in the image signal, and determine a change in focus by comparing an area where the windows overlap with each other before and after receiving the shake detection information.
The method according to claim 1,
The shake detection unit camera module, characterized in that it comprises an angular velocity sensor.
In the control method of the camera module to perform auto focusing,
Moving a focus lens to a reference position for performing the auto focusing;
Generating an image signal and detecting image frequency information from the image signal;
Determining an optimum focal length by identifying a high frequency component from the image frequency information;
Detecting shaking to stop performing the auto focusing; And
Checking the stoppage of the shaking to move the focus lens to resume performing auto focusing.
The method of claim 7, wherein
In the step of detecting the shaking to stop the auto focusing,
The control method of the camera module, characterized in that for detecting the shake using the angular velocity measured by the angular velocity sensor.
The method of claim 7, wherein
In the step of resuming performing the auto focusing,
And a reference position of the focus lens is set according to a change in focus generated before and after the auto focusing stops.

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