KR20140077666A - Camera module and control method thereof - Google Patents

Abstract

A camera module and a control method thereof are disclosed. The camera module includes: a lens unit which receives an optical signal regarding an imaging area; an imaging unit which converts the received optical signal into an image signal; an operation unit which generates focus value data according to image signals; a control unit which generates a lens control signal according to focus values generated by the operation unit; a lens driving unit which drives the lens unit according to the lens control signal; and a scan setting unit which sets a plurality of check positions of the lens unit using focusing information of the lens unit, receives focus values generated at the check positions of the lens unit, compares the received focus values, and determines an optimal lens position corresponding to the maximum value among the focus values.

Description

[0001] CAMERA MODULE AND CONTROL METHOD THEREOF [0002]

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

In recent years, the mobile communication terminal performs various functions such as photo shooting, video call, and the like in addition to voice transmission function. For this purpose, a camera module mounted on a mobile communication terminal is required to have an auto focus (AF) function.

The camera module of the auto focus function processes the image obtained through the image sensor as an image signal. Then, the camera module calculates the focus value using the edge that passes the processed image signal through the high pass filter, extracts the focus value in each picture unit, and outputs the focus value to the central processing unit . The central processing unit controls the actuator that drives the focus lens by determining the moving direction and the distance of the focus lens based on the calculated focus value. The central processing unit controls the actuator to move the focus lens and focus automatically.

The camera module to which the auto-focus function is applied consumes power by performing an unnecessary scan at the peak value of the focus value at the first scan position, depending on the actuator driving the focus lens for focus search. In addition, the camera module carries out unnecessary scanning, thereby increasing the time required to perform the auto focus operation, resulting in deterioration of performance.

Korea Patent Publication No. 2010-0020685

An object of the present invention is to provide a camera module and a control method thereof for improving the speed and accuracy of autofocusing by setting a plurality of check positions.

A camera module according to an embodiment of the present invention includes a lens unit that receives an optical signal for an imaging region, an imaging unit that converts the received optical signal into a video signal, an operation unit that generates focus value data based on the video signal, A control section for generating a lens control signal in accordance with the generated focus value, a lens driving section for driving the lens section in accordance with the lens control signal, and a plurality of check positions of the lens section using the adjustment amount information of the lens section, And a scan setting unit for comparing the received focus values and determining an optimal lens position corresponding to a maximum value of the focus value.

A method of controlling a camera module according to an exemplary embodiment of the present invention includes setting a plurality of check positions at a scan start position of a lens unit using lens adjustment amount information, moving a lens unit in each of a plurality of check positions, Setting a scan start position and a scan direction so as to find an optimum lens position corresponding to a maximum value of a focus value according to a result of the comparison, And performing autofocusing.

The camera module and its control method according to an embodiment of the present invention sets a plurality of check positions and compares the detected focus values for each position to determine an optimal lens position corresponding to a maximum value of the focus value, The speed of performing the focus can be improved. In addition, the camera module and the control method thereof according to an embodiment of the present invention can set various check positions according to the amount of projection of the lens unit, set the optimal scanning direction according to the position of the lens unit, So that the accuracy of the autofocus can be improved.

1 is a block diagram illustrating a camera module according to an exemplary embodiment of the present invention.
2 is a view illustrating scan positions set by the scan setting unit according to an embodiment of the present invention.
3 is a flowchart illustrating a method of controlling a camera module according to an exemplary embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific 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.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present invention, the term "comprises" or "having ", etc. is intended to specify that there is a feature, number, step, operation, element, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Hereinafter, a camera module and a control method thereof according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG.

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

1, a camera module according to an exemplary embodiment of the present invention includes a lens unit 110, a lens driving unit 120, an imaging unit 130, an operation unit 140, a control unit 150, a scan setting unit 160 And a storage unit 170. [0033]

The lens unit 110 collects the light reflecting the subject 50, and causes the image pickup unit 130 to form an image. For this, the lens unit 110 may be formed of an optical system having a plurality of lenses. In addition, the lens unit 110 may form an optical group for each function of the lenses. The lens portion 110 can move along the optical axis within the movement range to focus on the imaging region. In addition, the lens unit 110 may include a focus lens 115 that performs 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 lens driving unit 120 moves the lens unit 110. In particular, the lens driving unit 120 can move the position of the focus lens unit 110. Here, the lens driving unit 120 may include an actuator 122 and an actuator driver 124.

The actuator 122 is supplied with power and moves the lens unit 110 in the optical axis direction. The actuator driver 124 supplies power to the actuator 122 according to the lens control signal of the controller 150. [

The image sensing unit 130 senses the light passing through the lens unit 110 and generates a video signal on the image of the subject 50. The image pickup unit 130 can convert an optical signal for the subject 50 into an electric signal and output it. Here, the image sensing unit 130 may include an image sensing element for sensing the image of the subject 50. For example, the image sensing unit 130 may include a charge coupled devices (CCD) or a complementary metal oxide semiconductor (CMOS) image sensor. The image pickup unit 130 may provide the generated image signal to the operation unit 140 or the storage unit 170.

The operation unit 140 may perform signal processing on the image signal generated by the image pickup unit 130 to generate focus value data.

The control unit 150 may determine whether the subject 50 is appropriately focused using the focus value generated by the operation unit 140 and perform auto focusing. In addition, the controller 150 may provide a lens control signal to the lens driver 120 to perform autofocusing.

The scan setting unit 160 sets a plurality of check positions as a scan start position for performing autofocus using the adjustment amount information of the lens unit 110. [ Here, the scan setting unit 160 may determine the maximum value of the focus value in the first scan step with respect to the position of the subject 50 based on the adjustment amount information of the lens unit 110, Position, a second check position, or a third check position. Each of the first check position, the second check position, and the third check position may be set as the scan start position of the lens unit 110 in the second scan step. The first check position, the second check position, or the third check position may be set so as to find an accurate maximum value according to a change in the focus value.

For reference, the autofocus moves the lens unit 110 along the optical axis in the scan interval from the macro to the infinity with respect to the set imaging area, and scans the focus value for the subject 50 with a predetermined step size to find the optimum focus value Can be performed.

Here, the scan setting unit 160 will be described in detail with reference to FIG.

The scan setting unit 160 may set the first check position at a position corresponding to the over-focus distance and the start position as shown in FIG. Alternatively, the scan setting unit 160 may set the first check position on the basis of the time taken to image one frame in the image configured in units of frames set.

In addition, the scan setting unit 160 may set the second check position at a position spaced apart from the first check position by a preset step size. For example, the scan setting unit 160 may set a subject distance of about 60 cm, which is a position spaced apart from the infinity by a step size of about 2 μm, to the second check position.

Also, the scan setting unit 160 may set the third check position at a position spaced apart from the second check position by a preset step size. For example, the scan setting unit 160 may set a subject distance of about 30 cm, which is a position spaced by a step size of about 4 탆 from the second check position, to the third check position.

The scan setting unit 160 may perform an autofocus scan at the first check position to the third check position and receive the focus value generated for each check position from the operation unit 140. [ In addition, the scan setting unit 160 may determine the optimal lens position by comparing the focus value generated for each check position. Here, the optimum lens position can be set to the object distance at which the maximum value of the focus value occurs.

In the present invention, the focus value at the first check position is defined as the first focus value, the focus value at the second check position is defined as the second focus value, the focus value at the third check position is defined as the third focus value .

For example, when the first focus value, the second focus value, and the third focus value are compared (first focus value> second focus value> third focus value), the scan setting unit 160 sets the maximum value May exist before the first check position. That is, there may be a maximum of the focus value at a distance greater than the theoretical focal length position. At this time, the scan setting unit 160 may set the first check position to the secondary scan start position, set the scan direction to the reverse direction, and then provide the scan setting information to the controller 150. The control unit 150 may perform the secondary scan of the autofocus according to the scan setting information. Here, the scan setting information may include a check position and a scan direction set to the secondary scan start position.

Alternatively, the scan setting unit 160 compares the first focus value, the second focus value, and the third focus value (third focus value> second focus value> first focus value) It can be judged that the object exists within a distance of about 30 cm between the 3 check position and the macro. At this time, the scan setting unit 160 may set the third check position to the secondary scan start position, set the scan direction to the forward direction, and then provide the scan setting information to the controller 150. The control unit 150 may perform the secondary scan of the autofocus according to the scan setting information.

Alternatively, the scan setting unit 160 compares the first focus value, the second focus value, and the third focus value (i.e., the second focus value > the first focus value > the third focus value) 1 < / RTI > between the first check position and the second check position. At this time, the scan setting unit 160 may set the second check position to the secondary scan start position, set the scan direction to the reverse direction, and then provide the scan setting information to the controller 150. The control unit 150 may perform the secondary scan of the autofocus according to the scan setting information.

Alternatively, the scan setting unit 160 compares the first focus value, the second focus value, and the third focus value (i.e., the second focus value > the third focus value > the first focus value) It can be determined that the subject distance is between about 60 cm and about 30 cm between the second check position and the third check position. At this time, the scan setting unit 160 may set the second check position to the secondary scan start position, set the scan direction to the forward direction, and then provide the scan setting information to the controller 150. The control unit 150 may perform the secondary scan of the autofocus according to the scan setting information.

1, the storage unit 170 stores the image signal generated by the image sensing unit 130, a set value required to perform autofocus, a focus value generated by the arithmetic unit 140, or a position of the lens unit 110 Data and the like can be stored.

3 is a flowchart illustrating a method of controlling a camera module according to an exemplary embodiment of the present invention.

Referring to FIG. 3, a method of auto-focusing a camera module according to an exemplary embodiment of the present invention includes a step S111 of setting a plurality of check positions, which are scan start positions of a lens unit, (Step S113); comparing the detected focus value for each check position (step S115); calculating an optimum lens position corresponding to the maximum value of the focus value according to the comparison result A step S117 of setting a scan start position and a scan direction to search for a subject, and a step S119 of performing autofocus by moving the lens unit.

Hereinafter, a method of controlling a camera module according to an embodiment of the present invention will be described in detail with reference to a camera module shown in FIG.

In step S111, the scan setting unit 160 of the camera module may set a plurality of check positions as a scan start position for performing autofocus using the adjustment amount information of the lens unit 110. [

In step S113, the control unit 150 of the camera module controls the lens driving unit 120 to move the lens unit from the first check position to the third check position, and the calculation unit 140 can detect a focus value for each check position have.

In step S115, the scan setting unit 160 of the camera module may compare the received first focus value, the second focus value, and the third focus value after receiving the focus value for each check position from the operation unit 140. [

In step S117, the scan setting unit 160 of the camera module sets the scan start position and the scan direction according to the comparison result of the first focus value, the second focus value, and the third focus value.

The scan setting unit 160 may determine that the maximum value of the focus value exists before the first check position when the comparison result (the first focus value> the second focus value> the third focus value). Then, the scan setting unit 160 may set the first check position to the secondary scan start position, set the scan direction to the reverse direction, and provide the scan setting information to the controller 150.

Alternatively, if the comparison result (third focus value> second focus value> first focus value) indicates that the maximum value of the focus value is within a distance of about 30 cm between the third check position and the macro . Then, the scan setting unit 160 may set the third check position to the secondary scan start position, set the scan direction to the forward direction, and provide the scan setting information to the controller 150.

Alternatively, if the comparison result (second focus value> first focus value> third focus value) indicates a maximum focus value between the first check position and the second check position, the scan setting unit 160 sets the scan position It can be judged that it exists in the distance. Then, the scan setting unit 160 may set the second check position to the secondary scan start position, set the scan direction to the reverse direction, and provide the scan setting information to the controller 150.

Alternatively, when the comparison result (second focus value> third focus value> first focus value) is the comparison result, the maximum value of the focus value is about 60 cm between the second check position and the third check position, As shown in FIG. The scan setting unit 160 may set the second check position to the secondary scan start position, set the scan direction to the forward direction, and provide the scan setting information to the controller 150. [

In step S119, the control unit 150 of the camera module receives the scan setting information from the scan setting unit 160 and moves the lens unit 110 according to the scan setting information to perform autofocus.

The camera module and its control method according to an embodiment of the present invention sets a plurality of check positions and compares the detected focus values for each position to determine an optimal lens position corresponding to a maximum value of the focus value, The speed of performing the focus can be improved. In addition, the camera module and the control method thereof according to an embodiment of the present invention can set various check positions according to the amount of projection of the lens unit, set the optimal scanning direction according to the position of the lens unit, So that the accuracy of the autofocus can be improved.

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 scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

Claims (6)

A camera module for performing autofocusing,
A lens unit for receiving an optical signal for the imaging area;
An imaging unit for converting the received optical signal into a video signal;
An operation unit for generating focus value data according to the video signal;
A control unit for generating a lens control signal according to the focus value generated by the operation unit;
A lens driving unit for driving the lens unit according to the lens control signal; And
A plurality of check positions of the lens unit are set using the adjustment amount information of the lens unit, the focus values generated at a plurality of check positions of the lens unit are received, and the received focus values are compared with each other, And a scan setting unit for determining an optimal lens position corresponding to the lens position.
The method according to claim 1,
The scan setting unit
Wherein the controller sets the first check position, the second check position, or the third check position as a scan start position for performing autofocus using the adjustment amount information of the lens unit. 3. The method of claim 2,
The scan setting unit
A focus position, a focus position, a focus position, a focus position, a focus position, a focus position, a focus position, a focus position, Direction of the camera module.
Setting a plurality of check positions at a scan start position of the lens unit using lens conditioning amount information;
Moving a lens unit to each of the plurality of check positions and detecting a focus value for each check position;
Comparing the detected focus value for each check position;
Setting a scan start position and a scan direction to find an optimum lens position corresponding to a maximum value of the focus value according to a comparison result; And
And moving the lens unit to perform autofocusing.
5. The method of claim 4,
The scan setting unit
Wherein the control unit sets the first check position, the second check position, or the third check position as a scan start position for performing autofocus using the illumination amount information of the lens unit.
6. The method of claim 5,
The scan setting unit
A focus position, a focus position, a focus position, a focus position, a focus position, a focus position, a focus position, a focus position, Direction of the camera module.

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