KR20160087682A - Optical image stabilizer and method of controlling the same - Google Patents

Abstract

An optical image stabilizer according to an embodiment of the present invention includes: a motion sensor sensing vibration of a camera; a motion sensor resolution adjustment part adjusting a resolution of an output signal of the motion sensor; and a controller which moves a lens module on the basis of an output signal of the motion sensor resolution adjustment part and a position of a lens module. The controller can minimize power consumed in the optical image stabilizer in a preview mode, by reducing the resolution of the output signal of the motion sensor by controlling an operation of the motion sensor resolution adjustment part in the preview mode.

Description

TECHNICAL FIELD [0001] The present invention relates to an image stabilizer and a method of controlling the same,

The present invention relates to an image stabilization device and a control method of the image stabilization device.

Portable electronic devices with built-in camera modules incorporate an Optical Image Stabilizer (OIS) to prevent camera shake. The camera shake correction device actively detects camera shake and moves the lens module built in the camera module to stabilize the image physically by preventing the image from shaking due to camera shake.

The camera shake correction device detects the shaking motion through a gyro sensor, an acceleration sensor or a multi-axis sensor as a motion sensor and corrects the shaking by controlling the position of the lens module.

In order to control the position of the lens module, a voice coil motor (VCM) or an actuator such as a piezo actuator is used, and a microcontroller or logic driven at a high frequency is required in order to show quick response, . Due to this control, OIS consumes tens of mA (40mA to 100mA) of power compared to the products without OIS.

The patent documents described in the following prior art documents disclose an image stabilization imaging system that turns off the image stabilization device (OIS) when the focal length is not greater than the threshold value.

US 2012-0113515 A1

An object of the present invention is to provide a camera-shake correction device capable of minimizing power consumption.

SUMMARY OF THE INVENTION An object of the present invention is to provide a control method for a camera shake correction apparatus capable of minimizing power consumption.

According to an aspect of the present invention, there is provided an apparatus for correcting camera shake, including: a motion sensor for detecting a camera shake; A motion sensor resolution adjusting unit for adjusting a resolution of an output signal of the motion sensor; And a controller for moving the lens module based on an output signal of the motion sensor resolution adjusting unit and a position of the lens module, wherein the controller controls an operation of the motion sensor resolution adjusting unit in a preview mode, Thereby reducing the resolution.

In the preview mode, the controller can reduce the operation speed of the shake correction apparatus, extend the operation control period of the shake correction apparatus, or extend the data read period of the motion sensor.

In addition, in the case where the close focusing or zooming function is activated in the preview mode, the controller controls the operation of the motion sensor resolution adjusting unit to reduce the resolution of the output signal of the motion sensor, An operation of extending the operation control period of the shake correction apparatus, and an operation of extending the data reading period of the motion sensor.

According to the embodiment of the present invention, when the close focusing or zooming function is activated in the preview mode or the preview mode, it is possible to reduce the resolution of the motion sensor, reduce the operation speed of the camera shake correction device, By extending the operation control period or extending the data reading period of the motion sensor, the power consumed in the shake correction apparatus in the preview mode is minimized.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to this, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may appropriately define the concept of a term in order to best describe its invention The present invention should be construed in accordance with the spirit and scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing an image stabilization device according to an embodiment of the present invention; Fig.
FIGS. 2A and 2B illustrate exemplary images in a normal mode and a preview mode, respectively. FIG.
3 is a diagram showing an operation control cycle of the shake correction apparatus;
4 is a flowchart showing a control method of an image stabilization apparatus according to an embodiment of the present invention.
5 is a flowchart showing a control method of the shaking motion correcting apparatus according to another embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, specific advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

Prior to that, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may properly define the concept of the term in order to best explain its invention Should be construed in accordance with the principles and the meanings and concepts consistent with the technical idea of the present invention.

It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements have the same numerical numbers as much as possible even if they are displayed on different drawings.

Also, "first", "second", "one side". The terms "other" and the like are used to distinguish one element from another, and the element is not limited by the terms.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention, detailed description of related arts which may unnecessarily obscure the gist of the present invention will be omitted.

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

2A and 2B are diagrams illustrating exemplary images in a normal mode and a preview mode, respectively. The image in the normal mode shown in FIG. 2A is composed of 4608 × 3456 pixels in the case of a camera having an image sensor of 16M pixels (16 million pixels), the image in the preview mode is 640 × 480 (VGA), 1280 × 720 HD: High Definition), and 1920 × 1080 (FHD: Full High Definition) pixels.

As shown in FIGS. 2A and 2B, in a preview mode in a normal photographing mode, not in a moving image mode, an image is acquired at a resolution lower than that of the image sensor. The camera's preview mode displays images at a much lower resolution than normal photography, and the resolution of pixels that can be distinguished by the distance between the display and the user (typically 30 cm) on a 5.5-inch or smaller display, such as a mobile device, , High-precision control of one pixel or less is not necessary.

Since this mode occupies most of the shooting, in an embodiment of the present invention, when the close focusing or zooming function is activated in the preview mode or the preview mode, the resolution of the output signal of the motion sensor is reduced, The power consumed by the shake correction apparatus is minimized by reducing the operation speed of the apparatus, extending the operation control period of the shake correction apparatus, or extending the data reading period of the motion sensor.

Explanation PID Gyro sensor Preview mode Camera view confirmation mode with small display mounted Oppression ratio general Sensitivity and marginal general Video recording mode Still image (picture) shooting mode Suppression Ratio Highest Optimal control performance Centering mode When moving an actuator such as autofocus, Suppression ratio fixing Center (fixed) Fixed mode Mode for fixing the lens to a specific position desired Suppression ratio fixing Fixed (custom) Zoom mode Sensitivity and correction angle range by zoom and pen / tilt reference parameter change mode Suppression Ratio Highest Change Optimal and Limit Scope

Table 1 shows the PID and gyro sensor settings for each camera mode.

Referring to Table 1, it can be seen that five or more operation modes can be generated in the shake correction apparatus according to the correction performance or method. Some modes may not be used other than testing. In the preview mode, the suppression ratio of the PID is set to be normal and the sensitivity and the limit of the gyro sensor are set to be normal. However, as described above, since the resolution of the image displayed on the display in the preview mode is low, It is not necessary to operate the operation with high precision and high speed, and even if the sensitivity of the gyro sensor is greatly reduced, the user can not recognize the image quality change of the image displayed on the display in the preview mode.

1 is a view showing an image stabilization apparatus according to an embodiment of the present invention.

1 is a block diagram of a camera shake correction apparatus 100 according to an embodiment of the present invention. The camera shake correction unit 100 includes a gyro sensor 102 as a motion sensor for detecting camera shake, (Not shown) detected by the gyro sensor 102 output from the gyro resolution adjusting unit 104 and the position of the lens module 116 output from the hall sensor 118 A voice coil motor (VCM) 122 which is an actuator for moving the lens module 116 based on the control signal outputted from the controller 122, a controller 122 for outputting a control signal for moving the lens module 116 based on the control signal outputted from the controller 122, : Voice Coil Motor).

The gyro sensor 102 detects movement of the camera (not shown) and senses the shaking of the camera to output the angular velocity. The angular velocity output from the gyro sensor 102 and output through the gyro resolution adjustment unit 104 is obtained by removing the DC offset inherent in the gyro by the offset adjustment unit 106 and multiplying the angular velocity by the gyro integrator 108 to obtain an angle Is calculated. The gain adjustment unit 110 adjusts the gain of the signal output from the gyro integrator 108. [ When the obtained angle is multiplied by the lens-specific focal length, the moving distance of the lens is calculated.

The PID controller 112 controls the amount of current flowing through the VCM 114 so that the lens module 116 can be moved based on the output of the gain adjuster 110 and the output of the hall sensor 118.

The VCM 114 is an actuator for moving the lens module 116. The lens module 116 or the image sensor (not shown) is mounted on the VCM 114 using a principle that a force is generated when a current flows through a coil in a magnetic field formed by a magnet .

The hall sensor 118 is an element whose voltage varies with the intensity of the magnetic field. When the magnetic field is applied to the conductor through which the current flows, the Hall sensor 118 generates a voltage in a direction perpendicular to the current and the magnetic field. The Hall sensor 118 is proportional to the intensity of the magnetic field due to the movement of the lens module 116 Thereby generating a voltage.

The shake correction apparatus 100 shown in Fig. 1 may be incorporated in a camera (not shown) or may be incorporated in a portable device such as a smart phone equipped with a camera module (not shown).

The operation state of the camera module in the portable device equipped with the camera module can be transmitted from the host 120 to the shake correction apparatus 100. [ The host 120 may be an application processor (AP) in a smart phone that controls the operation of the shake correction apparatus 100 when the shake correction apparatus 100 is mounted on the smart phone.

When the camera or the camera module enters the preview mode, the host 120 transmits the control signal CS1 to the PID controller 112 to notify the PID controller 112 that the camera or the camera module has entered the review mode .

The PID controller 112 reduces the resolution of the gyro signal outputted from the gyro sensor 102 by applying the control signal CS2 to the gyro resolution adjusting unit 104 when the camera or the camera module enters the preview mode.

When the resolution of the gyro signal outputted from the gyro sensor 102 is reduced from, for example, 16 bits to 12 bits, the processing precision in the subsequent blocks for processing the gyro signal is lowered and the shake correction performance, , The power consumed by the shake correction apparatus 100 is reduced.

When the suppression ratio is lowered, the camera shake correction performance deteriorates and the camera shake correction can not be performed with high-precision control. However, since the resolution of the image displayed on the display (not shown) is low in the preview mode, Can not recognize.

In the preview mode, the controller 122 can reduce the power consumed by the shake correction apparatus 100 by reducing the operation speed of the shake correction apparatus 100 or extending the operation control period of the shake correction apparatus.

The controller 122 is operated by a clock having a predetermined frequency, for example, a frequency of 24 kHz. By lowering the frequency of the clock to a low frequency, for example, 12 KHz, the operation speed of the shake correction apparatus 100 is reduced The suppression ratio of the shake correcting apparatus 100 is lowered, and the power consumed in the shake correcting apparatus 100 can be reduced.

3 shows an operation control cycle of the shake correction apparatus.

3, the operation control period T of the shake correction apparatus includes a period for converting an output signal of the Hall sensor 118 into digital data, a gyro data operation period, a PID data operation period, a VCM control period, And an Idle period.

3, the operation speed of the shake correcting apparatus 100 is reduced and the shake correction performance of the shake correcting apparatus is lowered. However, when the operation control cycle T of the shake correcting apparatus 100 is extended longer, Can be reduced.

In the preview mode, the controller 122 applies a control signal CS3 to the gyro sensor 102 to extend the period of reading data from the gyro sensor 102, that is, the data reading period, The power consumed by the shake correction apparatus 100 can be reduced.

The power consumed by the shake correction apparatus 100 varies depending on the position of the lens module 116. The lens module 116 is located at the center in the horizontal direction and downward in the vertical direction, It is possible to minimize the power consumed in the portable terminal 100.

Accordingly, the controller 122 positions the lens module 116 in the center in the horizontal direction and downward in the vertical direction in order to minimize the power consumed in the shake correction apparatus 100. [

As described above, in the preview mode, the user can not recognize that the quality of the displayed image deteriorates even if the shake correction performance is lowered. Therefore, in the preview mode, the controller 122 decreases the operation frequency of the shake correction apparatus 100 The operation of extending the operation control period of the shake correction apparatus 100 and the operation of reducing the sensing sensitivity of the gyro sensor 102 are performed in the shake correction apparatus 100, Can be reduced.

In addition, when the camera module enters the preview mode, the controller 122 may cause the camera shake correcting apparatus 100 to perform operations to reduce the power consumed by the shake correction apparatus 100. More specifically, Only when the proximity focusing function or the zoom function is not activated in the state of entering the mode, the operation of reducing the power consumed by the shake correction apparatus 100 may be performed.

When the proximity focusing function or the zoom function is activated in the camera module, the image displayed on the display is enlarged and displayed. Therefore, when the suppression ratio of the shake correction apparatus 100 is lowered and the performance is degraded, It is possible to detect that the quality of the image is degraded.

Therefore, when the camera module enters the preview mode, only when the proximity focusing function or the zoom function is not activated, the camera 100 performs at least one of the operations for reducing power consumed by the shake correction apparatus 100 You may.

4 is a flowchart showing a control method of the shaking motion correcting apparatus according to an embodiment of the present invention.

In step S400, the controller 122 determines, based on the control signal CS1 from the host 120, whether or not the camera module enters the preview mode.

The controller 122 applies the control signal CS2 to the gyro resolution adjusting unit 104 to decrease the resolution of the output signal of the gyro sensor 102 and to output the image signal Thereby reducing the power consumed in the correction apparatus 100. [

In step S404, the controller 122 decreases the frequency of the clock applied to the shake correction apparatus 100 of the shake correction apparatus 100 to reduce the operation speed of the shake correction apparatus 100, By reducing the power consumed by the shake correcting apparatus 100. In this case,

In step S406, the controller 122 applies the control signal CS3 to the gyro sensor 102 to extend the data reading period of the gyro sensor 102 so that the power consumed by the shake correction apparatus 100 is reduced .

5 is a flowchart showing a control method of the shaking motion correcting apparatus according to another embodiment of the present invention.

In step S500, the controller 122 determines, based on the control signal CS1 from the host 120, whether or not the camera module enters the preview mode.

When the camera module enters the preview mode, the controller 122 determines based on the control signal CS1 from the host 120 whether the close focusing or zooming function of the camera module is activated.

The controller 122 applies the control signal CS2 to the gyro resolution adjusting section 104 to determine the resolution of the output signal of the gyro sensor 102 as So that the power consumed by the shake correction apparatus 100 is reduced.

In step S506, the controller 122 decreases the frequency of the clock applied to the shake correction apparatus 100 of the shake correction apparatus 100 to reduce the operation speed of the shake correction apparatus 100, By reducing the power consumed by the shake correcting apparatus 100. In this case,

The controller 122 applies the control signal CS3 to the gyro sensor 102 to extend the data reading period of the gyro sensor 102 for a longer time in step S508 so that the power consumed in the shake correction apparatus 100 .

According to the camera shake correction device and the camera shake correction device control method according to an embodiment of the present invention, when the close focusing or zooming function is not activated in the preview mode or the preview mode, the resolution of the output signal of the motion sensor is reduced By performing at least one selected from the group consisting of a step of reducing the operation speed of the shake correction apparatus, a step of extending the operation control period of the shake correction apparatus, and a step of extending the data reading period of the motion sensor, Can be minimized.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is clear that the present invention can be modified or improved.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

100: Anti-shake device 102: Gyro sensor
104: Gyro resolution adjustment unit 106: Offset adjustment unit
108: Gyro integrator 110: Gain adjuster
112: PID controller 114: VCM
116: Lens module 118: Hall sensor
120: Host 122: Controller

Claims (10)

A motion sensor for detecting camera shake;
A motion sensor resolution adjusting unit for adjusting a resolution of an output signal of the motion sensor; And
And a controller for moving the lens module based on an output signal of the motion sensor resolution adjusting unit and a position of the lens module,
Wherein the controller controls an operation of the motion sensor resolution adjusting unit in a preview mode to reduce a resolution of an output signal of the motion sensor. The method according to claim 1,
In the preview mode, the controller reduces the operation speed of the shake correction apparatus. The method according to claim 1,
In the preview mode, the controller extends the operation control period of the shake correction apparatus. The method according to claim 1,
In the preview mode, the controller extends the data reading period of the motion sensor. The method according to claim 1,
When the close focusing or zooming function is not activated in the preview mode, the controller controls the operation of the motion sensor resolution adjusting unit to reduce the resolution of the output signal of the motion sensor, An operation of extending the operation control period of the shake correction apparatus, and an operation of extending the data reading period of the motion sensor. (A) determining whether the controller is in a preview mode; And
(B) In the preview mode, the controller reduces the resolution of the output signal of the motion sensor. The method of claim 6,
And after the step (B), the controller reduces the operation speed of the shake correction apparatus. The method of claim 6,
And after the step (B), the controller extends the operation control period of the shake correction apparatus. The method of claim 6,
And after the step (B), the controller extends the data reading period of the motion sensor. The method of claim 6,
Wherein the controller controls the operation of the motion sensor resolution adjusting unit to reduce the resolution of the output signal of the motion sensor when the close focusing or zooming function is not activated after the step (B) The method comprising the steps of: reducing an operation speed; extending an operation control period of the shake correction apparatus; and extending a data reading period of the motion sensor.

Images