KR101669200B1 - Af calibration apparutus of camera module using dfov, af calibration method thereof and recording medium of the same method - Google Patents

Abstract

According to an embodiment of the present invention, it is possible to optimize the actuator driving code of the camera module using a diagonal field of view (DFOV), thereby eliminating an unnecessary section, that is, a dead zone, It is possible to reduce the waste of the automatic focus adjustment time due to the dead zone.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an automatic focus calibration apparatus, an autofocus calibration method, and a recording medium for a camera module using a DFOV,

The present invention relates to an autofocus calibration apparatus and method. And more particularly, to an autofocus calibration apparatus, an autofocus calibration method, and a recording medium thereof for a camera module using a DFOV.

FIG. 1 is a view schematically showing a structure of a general auto-focus camera module. 1, the conventional camera module 20 includes a focus adjustment lens 24 disposed on the front surface of an image sensor 26 and a focus lens 24 for focusing a subject image by an actuator 22 that receives a drive signal of the actuator drive unit 28, And moves from the position 244 to the near focus position 242 to find the optimum focus position.

However, due to lens deviation during production of the camera module, deviation of the dynamic characteristics of the actuator, deviation of electrical characteristics of the actuator, and assembly deviation of the camera module, automatic focus characteristic deviations occur for each camera module mass-produced. Therefore, the camera modules have different actuator driving codes in the long distance / short distance, and the conventional camera modules have been applied to a range of the long distance / short distance actuator driving code all together without consideration.

2 is a graph showing various states in which a lens position of a general auto-focus camera module changes according to an actuator driving code. In the graph shown in Fig. 2, the axis of abscissas is the actuator drive code, and the axis of ordinate indicates the lens position. As shown in FIG. 2, even if the same actuator driving code is input, it can be seen that the camera modules are driven to different lens positions.

Therefore, there is a need for an automatic focus calibration apparatus and method of a camera module that can correct an actuator drive of different camera modules and determine an optimum actuator drive code for each camera module.

The present invention provides an automatic focus calibration apparatus, an autofocus calibration method, and a recording medium thereof for a camera module using a DFOV that corrects an actuator driving code of a camera module using a DFOV (Diagonal Field Of View) do.

In addition, the present invention provides an automatic focus calibration device of a camera module using a DFOV that can optimize an actuator driving code by calculating a distance and near-field DFOV of a camera module through a DFOV chart and determining an actuator driving code thereof, And a recording medium therefor.

The present invention relates to an automatic focus calibration apparatus for a camera module including an actuator, comprising: a DFOV chart displaying at least one reference mark; A camera module which is located apart from the DFOV chart by a predetermined imaging distance and generates an image by imaging the DFOV chart toward the DFOV chart; A DFOV arithmetic unit for calculating DFOV information including a near-field DFOV and a far-field DFOV based on the imaging distance information corresponding to the imaging distance and the image information of the generated image; And a code determiner for determining a local actuator driving code and a remote actuator driving code corresponding to the near-field DFOV and the remote DFOV, respectively.

The DFOV chart has a rectangular shape, and at least one reference mark may be four reference marks distributed so as to correspond to each outer side of the rectangular shape.

The image information may include diagonal length information of a virtual rectangle shape formed by at least one reference mark and image outline information of the image.

The generated image may have a rectangular shape, and the image outlier information may be diagonal length information corresponding to the diagonal length of the image.

The DFOV information can be calculated by the following equation (1).

[Equation 1]

Where DFOV is the viewing angle corresponding to the diagonal length of the image in the camera module, A is the diagonal length of the image, and B is the imaging distance.

The diagonal length information of the image can be obtained based on the diagonal length information of the virtual rectangle shape and the pixel information of the image.

The diagonal length information of the image can be obtained by the following equation (2).

&Quot; (2) "

Where A is the diagonal length of the image, C is the diagonal length of the imaginary rectangle shape, P1 is the diagonal pixel length of the image, and P2 is the diagonal pixel length of the virtual rectangle shape.

The near field actuator driving code may be an actuator driving code corresponding to the near focus position of the camera module and the far field actuator driving code may be defined as an actuator driving code corresponding to the far focus position of the camera module.

A jig for fixing the camera module; And an image grabber board interconnecting the camera module and the DFOV operation unit and transmitting the image information to the DFOV operation unit.

According to another aspect of the present invention, there is provided an automatic focus calibration method for a camera module including an actuator, wherein the camera module is located at a predetermined distance from the DFOV chart on which at least one reference mark is displayed and is imaged toward the DFOV chart Generating an image (S10); Calculating (S20) the DFOV information including the near-field DFOV and the far-field DFOV based on the imaging distance information corresponding to the imaging distance and the image information of the generated image; And determining (S30) a near-field actuator driving code and a far-field actuator driving code corresponding to the near-field DFOV and the far-field DFOV, respectively, and the code determining section (S30).

In the DFOV information operation step S20 of the DFOV operation unit, the image information may include diagonal length information of a virtual rectangle shape formed by at least one reference mark and image outline information of the image.

The generated image may have a rectangular shape, and the image outlier information may be diagonal length information corresponding to the diagonal length of the image.

The DFOV information can be calculated by the following equation (1).

[Equation 1]

Where DFOV is the viewing angle corresponding to the diagonal length of the image in the camera module, A is the diagonal length of the image, and B is the imaging distance.

The diagonal length information of the image can be obtained based on the diagonal length information of the virtual rectangle shape and the pixel information of the image.

The diagonal length information of the image can be obtained by the following equation (2).

&Quot; (2) "

Where A is the diagonal length of the image, C is the diagonal length of the imaginary rectangle shape, P1 is the diagonal pixel length of the image, and P2 is the diagonal pixel length of the virtual rectangle shape.

In addition, the present invention provides a recording medium on which a computer-readable program capable of executing a method of autofocus calibration of a camera module using DFOV is recorded.

According to an embodiment of the present invention, the actuator driving code of the camera module can be optimized using a diagonal field of view (DFOV).

In addition, by optimizing the actuator driving code, unnecessary sections such as a dead zone can be removed from the camera module, and the automatic focus adjustment time due to the dead zone can be saved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified illustration of the structure of a conventional autofocus camera module,
FIG. 2 is a graph showing various states in which the lens position of a general auto-focus camera module changes according to an actuator driving code,
3 is a graph showing a dead zone where the lens position is not changed according to an actuator driving code of a general auto focus camera module,
FIG. 4 is a schematic view showing a configuration of an embodiment of an automatic focus calibration apparatus for a camera module using DFOV according to the present invention.
FIG. 5 is a diagram illustrating a DFOV chart and a relative position of a generated image outline in an automatic focus calibration apparatus of a camera module using a DFOV according to the present invention,
6 is a graph showing the relationship between DFOV information and focal position calculated according to an embodiment of the automatic focus calibration apparatus of a camera module using DFOV according to the present invention,
FIG. 7 is a graph illustrating a state of determining a remote actuator driving code and a near-field actuator driving code based on the DFOV information calculated according to an embodiment of the automatic focus calibration apparatus of a camera module using the DFOV according to the present invention,
FIG. 8 is a flowchart sequentially illustrating an automatic focus calibration method of a camera module using a DFOV according to an embodiment of the present invention.

Before describing an embodiment of the calibration device of the present invention, a distance dead zone and a near dead zone are defined in the auto focus control of a general camera module.

3 is a graph showing a dead zone in which the lens position is not changed according to an actuator driving code of a general auto focus camera module. In the graph of Fig. 3, the abscissa is the actuator drive code, and the ordinate is the lens position. As shown in FIG. 3, even if the code value of the actuator driving code is lowered, the position of the lens does not change the lens position. In this case, the section to the lens minimum distance position can be defined as the remote dead zone. On the other hand, even if the code value of the actuator driving code is increased, an interval in which the lens position does not change may occur. In this case, the section to the maximum position in the lens close range can be defined as a near dead zone.

<Auto focus of camera module calibration  Devices>

4 is a block diagram schematically showing the configuration of an embodiment of an automatic focus calibration apparatus for a camera module using DFOV according to the present invention. 4, an embodiment of the calibration apparatus according to the present invention includes a DFOV chart 10, a camera module 20, a DFOV calculating unit 30, and a code determining unit 40. As shown in FIG.

The present embodiment grasps the actual driving of the actuator 22 mounted on the camera module 20 through the DFOV calculation so as to determine the near-field actuator driving code and the far-field actuator driving code corresponding to the near-field DFOV and the far- . Thus, the actuator driving code of the camera module 20 can be corrected.

Hereinafter, the configuration of this embodiment will be described in detail with reference to FIG.

The camera module 20, in which calibration is performed according to the present embodiment, includes an actuator 22 for adjusting the displacement of the lens 24 for autofocusing. The actuator 22 may be a Micro-electromechanical Systems (MEMS) actuator or a Voice Coil Motor (VCM) actuator.

At least one reference mark 110 is displayed on the DFOV chart 10 so that a clear image can be obtained by the image sensor 26 of the camera module 20. [ In this embodiment, four reference marks 110 are symmetrically displayed. In the DFOV calculation, a diagonal length of a virtual rectangle formed by these reference marks 110 is used.

In addition, the DFOV chart 10 constitutes a light source 70 on the opposite side of the camera module 20 so as to function as a light source for imaging. As the light source 70, an LED (Light Emitting Diode) can be used.

The camera module 20 is configured to generate an image by positioning the DFOV chart 10 at a predetermined distance from the DFOV chart 10 and imaging the DFOV chart 10 toward the DFOV chart 10. The separated imaging distance is used to obtain DFOV information in advance.

The DFOV calculating unit 30 calculates the DFOV information including the near-field DFOV information and the far-field DFOV information based on the imaging distance information corresponding to the imaging distance and the image information of the generated image.

The image information received from the camera module 20 by the auto focus scan by the drive of the actuator 22 of the camera module 20 can capture an image of the outside of the DFOV chart 10 in addition to the DFOV chart 10, ) Only the image inside the outer frame can be captured. In each case, the reference mark 110 sets the imaging distance to be included in the image.

The code determining unit 40 determines the near field actuator driving code and the far field actuator driving code corresponding to the near field DFOV and the far field DFOV based on the DFOV information received from the DFOV calculating unit 30. [ Here, the near-field actuator drive code is an actuator drive code corresponding to the near focus position of the camera module 20, and the far-field actuator drive code means an actuator drive code corresponding to the far focal position of the camera module 20. [

The DFOV arithmetic unit 30 and the code determining unit 40 may be constituted by a computer including a memory and a CPU (Central Processing Unit) necessary for the arithmetic operation.

FIG. 5 is a view showing the DFOV chart and the relative positions of the generated image outline in the automatic focus calibration apparatus of the camera module using the DFOV according to the present invention. The acquisition of DFOV information in this embodiment will be described in detail with reference to FIG.

5, the image information includes diagonal length information of a virtual rectangle shape formed by at least one reference mark 110 and image outline information of the image, and the image generated by the imaging is rectangular . The image outlier information may be diagonal length information corresponding to the diagonal length of the image.

In this case, the DFOV information can be calculated by the following equation (1).

Where DFOV is the viewing angle corresponding to the diagonal length of the image in the camera module 20, A is the diagonal length of the image, and B is the imaging distance.

Here, the diagonal length information of the image is information based on the diagonal length information of the virtual rectangle shape and the pixel information of the image. That is, in the case of the image information, the pixel information of the image generated by the imaging and can be relatively calculated through the pixel information.

That is, the diagonal length information of the image can be obtained by the following equation (2).

Where A is the diagonal length of the image, C is the diagonal length of the imaginary rectangle shape, P1 is the diagonal pixel length of the image, and P2 is the diagonal pixel length of the virtual rectangle shape.

FIG. 6 is a graph showing the relationship between DFOV information and focus position calculated according to an embodiment of the automatic focus calibration apparatus of a camera module using the DFOV according to the present invention. The distance actuator driving code and the near field actuator driving code are determined based on the DFOV information calculated according to an embodiment of the present invention.

As shown in FIGS. 6 and 7, it can be seen that the DFOV information and the distance focal position and the near focus position according to the position of the lens are in a linear relationship. Therefore, when the lens position is at the remote DFOV and the near-field DFOV, the code determination unit 40 can linearly determine the remote actuator drive code and the near-field actuator drive code so as to correspond thereto.

In addition, the present embodiment may further include a jig 50 for fixing the camera module 20 so that the imaging direction is not changed. The DFOV calculating unit 30 may further include an image grabber board 60 for interconnecting the camera module 20 and the DFOV calculating unit 30 to transmit image information to the DFOV calculating unit 30. [ Here, the image grabber board 60 may use a PCI interface or a USB interface.

<Auto focus of camera module calibration  Method>

FIG. 8 is a flowchart sequentially illustrating an automatic focus calibration method of a camera module using a DFOV according to an embodiment of the present invention. An automatic focus calibration method of a camera module according to the present invention will be described with reference to FIG. First, the camera module 20 is positioned at a predetermined distance from the DFOV chart 10 on which at least one reference mark 110 is displayed and is imaged toward the DFOV chart 10 to generate an image (S10).

Next, the DFOV computing unit 30 computes DFOV information including the near-field DFOV information and the far-field DFOV information based on the imaging distance information corresponding to the imaging distance and the image information of the generated image (S20).

Next, an embodiment of the automatic focus calibration method of the camera module 20 using the DFOV by determining the near-field actuator drive code and the far-field actuator drive code corresponding to the near-field DFOV and the far-field DFOV, respectively (S30) . Of course, the determined local actuator driving code and the remote actuator driving code are stored in a non-volatile memory (not shown) built in the camera module 20, thereby optimizing the driving of the camera module 20.

In the DFOV information operation step S20 of the DFOV operation unit 30, the generated image and image information, the calculation of the DFOV information, and the method of acquiring the diagonal length information of the image are as described above in the calibration apparatus.

The automatic focus calibration method of the camera module 20 using the above-described DFOV may be implemented by a computer-readable program that can execute the automatic focus calibration, and may be implemented through a recording medium on which the automatic focus calibration is performed.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. In addition, the scope of the present invention is indicated by the following claims rather than the above detailed description. Also, all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

10: DFOV chart
20: Camera module
22: Actuator
24: Lens
26: Image sensor
28:
30: DFOV computing unit
40: code determination unit
50:
60: Grabber board
70: Light source
110: Reference mark
120: Outside the DFOV chart
130: Outer image
140: virtual rectangle outline
242: Close focus position of lens
244: Far focus position of lens

Claims (16)

An automatic focus calibration apparatus for a camera module including an actuator,
A DFOV chart displaying at least one fiducial mark;
A camera module positioned at a predetermined imaging distance from the DFOV chart and generating an image by imaging the DFOV chart toward the DFOV chart;
A DFOV computing unit for computing DFOV information including a near-field DFOV and a far-field DFOV based on the imaging distance information corresponding to the imaging distance and the image information of the generated image; And
And a code determiner for determining a near-field actuator drive code and a far-field actuator drive code corresponding to the near-field DFOV and the far-field DFOV, respectively.
The method according to claim 1,
The DFOV chart has a rectangular shape,
Wherein the at least one reference mark is DFOV, which is four reference marks distributed so as to correspond to the respective outer sides of the rectangular shape.
The method according to claim 1,
Wherein the image information includes diagonal length information of a virtual rectangle shape formed by the at least one reference mark and information of an outermost image of the image.
The method of claim 3,
The generated image has a rectangular shape,
Wherein the image outlier information is DFOV, which is diagonal length information corresponding to a diagonal length of the image.
5. The method of claim 4,
Wherein the DFOV information is calculated by the following equation (1): DFOV =
[Equation 1]

Wherein DFOV is a viewing angle corresponding to a diagonal length of the image in the camera module, A is a diagonal length of the image, and B is an imaging distance.
5. The method of claim 4,
Wherein the diagonal length information of the image is obtained based on the diagonal length information of the virtual rectangle shape and the pixel information of the image.
The method according to claim 6,
Wherein the diagonal length information of the image is obtained by the following equation (2): DFOV =
&Quot; (2) &quot;

Where A is the diagonal length of the image, C is the diagonal length of the imaginary rectangle, P1 is the diagonal pixel length of the image, and P2 is the diagonal pixel length of the imaginary rectangle.
The method according to claim 1,
Wherein the near field actuator driving code is an actuator driving code corresponding to a near focus position of the camera module,
Wherein the remote actuator driving code is DFOV, which is an actuator driving code corresponding to a far focal position of the camera module.
The method according to claim 1,
A jig for fixing the camera module; And
And an image grabber board for interconnecting the camera module and the DFOV calculating unit to transmit the image information to the DFOV calculating unit.
A method for automatic focus calibration of a camera module including an actuator,
A step (S10) of generating an image by positioning the camera module at a predetermined distance from the DFOV chart on which at least one reference mark is displayed, and imaging the DFOV chart toward the DFOV chart;
(S20) of calculating DFOV information including a near-field DFOV and a far-field DFOV based on the image pickup distance information corresponding to the image pickup distance and the image information of the generated image; And
And determining (S30) a near-field actuator drive code and a far-field actuator drive code corresponding to the near-field DFOV and the far-field DFOV, respectively, by the code determination unit.
11. The method of claim 10,
In the DFOV information calculation step (S20) of the DFOV calculation unit,
Wherein the image information includes diagonal length information of a virtual rectangle shape formed by the at least one reference mark and information on the outermost image of the image.
12. The method of claim 11,
The generated image has a rectangular shape,
Wherein the image outlier information is DFOV, which is diagonal length information corresponding to a diagonal length of the image.
13. The method of claim 12,
Wherein the DFOV information is calculated by the following equation (1): DFOV =
[Equation 1]

Wherein DFOV is a viewing angle corresponding to a diagonal length of the image in the camera module, A is a diagonal length of the image, and B is an imaging distance.
13. The method of claim 12,
Wherein the diagonal length information of the image is obtained based on the diagonal length information of the virtual rectangle shape and the pixel information of the image.
15. The method of claim 14,
Wherein the diagonal length information of the image is obtained by the following equation (2): DFOV =
&Quot; (2) &quot;

Where A is the diagonal length of the image, C is the diagonal length of the imaginary rectangle, P1 is the diagonal pixel length of the image, and P2 is the diagonal pixel length of the imaginary rectangle.
A recording medium on which a computer-readable program capable of executing an automatic focus calibration method of a camera module using a DFOV according to any one of claims 10 to 15 is recorded.

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