WO2016026229A1

WO2016026229A1 - Focusing control method and apparatus

Info

Publication number: WO2016026229A1
Application number: PCT/CN2014/091443
Authority: WO
Inventors: 张文娜; 李黎国; 成嘉
Original assignee: 中兴通讯股份有限公司
Priority date: 2014-08-18
Filing date: 2014-11-18
Publication date: 2016-02-25
Also published as: CN105357429A

Abstract

Provided are a focusing control method and apparatus. The focusing control method comprises: acquiring a current shooting position of a shooting apparatus; judging whether the current shooting position is stable or not; acquiring a motor initial current corresponding to the current shooting position when it is determined that the current shooting position is stable; and controlling a motor to drive for focusing according to the motor initial current.By adopting the technical scheme provided in the present invention, the problems that a shooting effect is poor and a focusing speed is relatively low due to a fixed motor initial current are solved, thereby effectively improving the shooting effect, and increasing the focusing speed during shooting.

Description

Focus control method and device

Technical field

The present invention relates to the field of image processing, and in particular to a focus control method and apparatus.

Background technique

With the rapid development of camera technology and the demand for high-quality images, camera technology is facing increasing demands, and focus technology has become an important area that cannot be ignored. During image capture, the position between the camera and the subject is relatively variable; in order to keep the preview and camera images clear, the position of the lens needs to be constantly adjusted during the framing process. For focusing.

Focus plays a very important role in the technical fields of camera, photo and scanning. The movement of the lens during focusing is driven by the voice coil motor. By inputting different current values to the voice coil motor, the voice coil motor drives the lens to a different position to achieve the focusing process. Due to the influence of static friction, the motor will be driven only when the electromagnetic force generated by the drive current is greater than the static friction. The current required to overcome this static friction is called the initial motor current.

During the shooting process, the direction of the user's handheld device is constantly changing, and the static friction of the motor in the camera module changes, resulting in different starting currents required by the motor. If during the focusing process, the motor starting current is set to a fixed value: (1) When the fixed current value is greater than the initial current value, the motor is subjected to an excessive driving force, resulting in blurring of the scene at infinity. (2) When the fixed current value is smaller than the initial current value, the motor receives a small driving force, causing it to take a long time out of the nonlinear region and lower the focusing speed.

In view of the problems in the prior art that the initial effect of the motor is fixed, the shooting effect is poor, and the focusing speed is slow, etc., an effective solution has not been proposed yet.

Summary of the invention

A main object of the embodiments of the present invention is to provide a focus control method and apparatus for solving problems such as poor shooting performance and slow focus speed due to fixed initial current of the motor.

In order to achieve the above object, according to an embodiment of the present invention, a focus control method includes: acquiring a current photographing orientation of a photographing device; determining whether the current photographing orientation is stable; determining the current shot When the photographing orientation is stable, a motor initial current corresponding to the current photographing orientation is acquired; and the motor is driven to perform focusing according to the motor initial current.

Preferably, determining whether the current shooting orientation is stable comprises: obtaining a difference between the current shooting orientation and a shooting orientation of the first N shootings, where N is a natural number not less than 1; and an absolute value of the M difference is less than When the first preset threshold is used, it is determined that the current shooting orientation is in a stable state; otherwise, it is determined that the current shooting orientation is in an unstable state, where M≤N.

Preferably, acquiring the initial motor current corresponding to the current photographing orientation comprises: comparing whether the current photographing orientation is consistent with one or more stable historical photographing orientations in the history record; when the judgment result indicates inconsistency, according to The stabilized current shooting orientation determines the initial motor current.

Preferably, when the determination result indicates the coincidence, the motor initial current corresponding to the historical shooting direction is taken as the motor initial current corresponding to the current shooting direction.

Preferably, determining whether the current shooting orientation is consistent with one or more stable historical shooting directions in the historical record comprises: obtaining an absolute value of the difference between the current shooting orientation and the historical shooting orientation; When the absolute value of the difference is less than the second preset threshold, determining that the current shooting direction is consistent with the historical shooting direction; otherwise, determining that the current shooting direction is consistent with the historical shooting direction.

Preferably, acquiring the motor initial current corresponding to the current photographing orientation comprises one of: determining the motor initial current according to a preset correspondence relationship between the photographing orientation and the motor initial current; and a preset function according to the photographing orientation and the motor initial current. The relationship determines the initial motor current.

Preferably, the photographing orientation includes: a placement position and/or an angle of the photographing device at the time of photographing.

According to another embodiment of the present invention, a focus control apparatus includes: a first acquisition module configured to acquire a current photographing orientation of the photographing device; a determination module configured to determine whether the current photographing orientation is stable; The acquiring module is configured to acquire a motor initial current corresponding to the current photographing orientation when determining that the current photographing orientation is stable; and the control module is configured to perform focusing according to the motor initial current control motor driving.

Preferably, the determining module includes: an acquiring unit configured to acquire a difference between the current shooting orientation and a shooting orientation of the first N shots, where N is a natural number not less than 1; and the determining unit is set to be M times When the absolute value of the difference is less than the first preset threshold, it is determined that the current photographing orientation is in a stable state; otherwise, it is determined that the current photographing orientation is in an unstable state, where M≤N.

Preferably, the second obtaining module includes: a comparing unit configured to compare whether the current photographing orientation is consistent with one or more stable historical photographing orientations in the history record; and the determining unit is configured to indicate in the judgment result In case of inconsistency, the initial motor current is determined based on the current shooting orientation after stabilization.

Preferably, the determining unit is configured to set a motor initial current corresponding to the historical shooting direction as a motor initial current corresponding to the current shooting direction when the determination result indication is consistent.

According to the embodiment of the present invention, the technical means for determining the initial motor current corresponding to the current shooting orientation according to the current shooting orientation after the stabilization is adopted, and the problem that the shooting effect is poor due to the fixed initial current of the motor and the focusing speed is slow is solved in the related art. , thus effectively improving the shooting effect and improving the focusing speed at the time of shooting.

DRAWINGS

The drawings described herein are intended to provide a further understanding of the invention, and are intended to be a part of the invention. In the drawing:

1 is a flow chart of a focus control method according to an embodiment of the present invention;

2 is a block diagram showing the structure of a focus control apparatus according to an embodiment of the present invention;

3 is a block diagram showing another structure of a focus control device according to an embodiment of the present invention;

4 is a flow chart of a focus control method in accordance with a preferred embodiment of the present invention.

detailed description

The invention will be described in detail below with reference to the drawings in conjunction with the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict.

1 is a flow chart of a focus control method in accordance with an embodiment of the present invention. As shown in Figure 1, the method includes:

Step S102, acquiring a current photographing orientation of the photographing device;

Step S104, determining whether the current shooting orientation is stable;

Step S106, when it is determined that the current shooting orientation is stable, acquiring a motor initial current corresponding to the current shooting orientation;

In step S108, the motor is driven to perform focusing according to the motor initial current.

Through the above various processing steps, since the initial motor current can be determined according to the stabilized shooting orientation, and thus the motor driving for focusing is controlled, the shooting effect due to the initial value of the motor initial value can be fundamentally avoided, and Problems such as slower focusing speed.

In a preferred embodiment, the determining process in step S104 may be expressed in the following form, but is not limited thereto:

Obtain the difference between the current shooting orientation and the shooting orientation of the previous N shots, and N is a natural number not less than 1;

When the absolute value of the M times difference is less than the first preset threshold, it is determined that the current shooting direction is in a stable state; otherwise, it is determined that the current shooting direction is in an unstable state, where M≤N. The values of N and M may be set by the user or the manufacturer according to actual conditions, but are not limited thereto.

There are a plurality of implementations of the step S106. In a preferred embodiment, the following process may be implemented: comparing whether the current shooting orientation is consistent with one or more stable historical shooting orientations in the historical record; At the time, the initial motor current is determined based on the current shooting orientation after stabilization.

In order to improve the focusing speed during shooting, when the determination result indications match, the motor initial current corresponding to the above-described history shooting direction may be used as the motor initial current corresponding to the current shooting direction. In this way, it is avoided to query the initial motor current every time and save the query time of the initial motor current.

In a preferred implementation, whether the current shooting orientation is consistent with one or more stable historical shooting orientations in the history may be determined by:

Obtaining an absolute value of the difference between the current shooting orientation and the historical shooting orientation; determining that the current shooting orientation is consistent with the historical shooting orientation when the absolute value of the difference is less than the second preset threshold; otherwise, determining the current shooting orientation and The above historical shooting directions are the same.

Step S106 can be implemented in various manners, for example, by one of the following methods: (1) determining the initial motor current according to a preset correspondence relationship between the shooting orientation and the initial motor current; (2) determining the initial current according to the shooting orientation and the motor. The preset function relationship determines the initial motor current described above.

Preferably, the above-mentioned photographing orientation may include, but is not limited to, a placement position and/or an angle of the photographing device at the time of photographing.

A preferred implementation of the above method embodiment is as follows:

S1. Turn on the camera and enter the camera preview mode to read the position information of the position sensor such as the gyroscope.

S2, comparing the position information with the previous N times to determine whether the position of the current user's handheld or fixed device has stabilized; if the position of the device is unstable, return to S1 and continue to read the location information; if the current device If the position is stable, proceed to S3.

S201: Record device location information that is read N times before, and calculate an absolute value of a difference between each adjacent two location information;

S202. Set a stability threshold.

S203. Compare the absolute value of the position information difference in S201 with the stable threshold set by S202. If the absolute value of the difference M times is less than or equal to the stability threshold, it is judged that the device position has stabilized, and the device position information is recorded; otherwise, the device position is still changed, and S1 and S2 are repeated.

S3. The position information after the device is stabilized is compared with the position information when the device is stable last time, and it is determined whether the device position information changes. If the device location information is the same as the last device location information, proceed to S6 to directly complete the focus operation according to the previous focus information; if the device location information is different from the previous device location information, proceed to S4.

S301. Record last device stable position information;

S302. Set a jitter threshold.

S303. Compare the last stable information in S301 with the current stable information, and calculate an absolute value of the difference. If the absolute value is less than or equal to the jitter threshold, it is determined that the device location information has not changed, and S6 is performed to directly complete the focus; if the absolute value is greater than the jitter threshold, the device position is determined to be changed, and the updata command and the current location information of the device are sent. .

S4, obtaining a corresponding initial motor current according to the position information of the current device by a table lookup method (a table of relationship between position information and initial motor current) or a function calculation (a functional relationship between position information and initial motor current).

S401. Set a relationship table between the position information and the initial current of the motor, or a function relationship between the position information and the initial current of the motor;

S402. Calculate the initial motor current using the relationship table or the function relationship in S401 according to the current position information in S303.

S5. Transfer the initial motor current information to the motor drive.

S6, the motor drives the feedback information to the focusing algorithm, and obtains a suitable focusing scheme, such as a focus step value and a step_num, and then performs a focusing operation through a focus drive.

In this embodiment, a focus control device is further provided for implementing the above method. As shown in FIG. 2, the device includes:

The first obtaining module 20 is configured to acquire a current photographing orientation of the photographing device;

The determining module 22 is connected to the first obtaining module 20 and configured to determine whether the current shooting orientation is stable;

The second obtaining module 24 is connected to the determining module 22, and configured to acquire a motor initial current corresponding to the current shooting direction when determining that the current shooting orientation is stable;

The control module 26 is coupled to the second acquisition module 24 and is configured to control the motor drive for focusing in accordance with the motor initial current.

In a preferred embodiment, as shown in FIG. 3, the determination module 22 can include the following processing units:

The obtaining unit 220 is configured to acquire a difference between the current shooting orientation and the shooting orientation of the previous N shootings, where N is a natural number not less than 1;

The determining unit 222 is connected to the obtaining unit 220, and is configured to determine that the current shooting direction is in a stable state when the absolute values of the M times difference values are all smaller than the first preset threshold, otherwise, determining that the current shooting direction is in an unstable state Where M ≤ N.

In this embodiment, the second obtaining module 24 includes: a comparing unit 240 configured to compare whether the current shooting orientation is consistent with one or more stable historical shooting directions in the history record; the determining unit 242 is configured to be When the judgment result indicates inconsistency, the motor initial current is determined based on the stabilized current photographing orientation.

The determining unit 242 is configured to set a motor initial current corresponding to the historical shooting direction as a motor initial current corresponding to the current shooting direction when the determination result indication is consistent

It should be noted that each of the above modules may be implemented by software or hardware. For the latter, the following forms may be implemented, but are not limited thereto: each of the above modules is located in the same processor, or each of the above modules is located Different processors.

In order to better understand the above embodiments, the following detailed description will be given in conjunction with the preferred embodiments.

As shown in FIG. 4, this embodiment describes a focus control method for improving camera focus speed and accuracy, including the following steps:

Step S402. Turn on the camera and enter the camera preview mode to read the position information of the position sensor such as the gyroscope.

Step S404. By comparing the read location information with the previous N times, it is determined whether the location of the current user's handheld or fixed device has stabilized.

(1) Recording the position information of the N consecutive readings, and calculating the absolute value of the difference of the position information of each adjacent two times, wherein N can be set according to the demand.

(2) Set the stability threshold. The stability threshold can be set according to the requirements. If the threshold is set too high, the probability of being judged to be stable is lowered, the time for stable judgment is increased, and the focus speed is slowed down. If the threshold is set too small, it is easy to judge that the position is stable, misjudgment is generated, and the judgment is continuously issued. Focus action.

(3) With the position read N times, the absolute value of the difference between each adjacent two values is used, and the absolute value is compared with the set stable threshold. If there is a continuous M-time difference absolute value less than or equal to the stability threshold, it is judged that the device position has been stabilized, and the current device position information is recorded. Otherwise, the device location is still being adjusted and continues to read the current location information of the device. Among them, the value of M can be set according to user needs. If the M setting is too large, it is judged that the probability of the position is stable is small, the waiting time is long, and the focusing speed is slowed down; if the M setting is too small, the small amplitude jitter is easily judged as the positional stability, the number of focusing times is increased, and it is not conducive to Accurate focus.

Step S406. Determine whether the current device location information and the location information when the last device is stable are the same.

(1) Record the position information when the device was stable last time, or record the device stable position information for multiple times as a query.

(2) Set the jitter threshold, which can be set according to user requirements. If the jitter threshold is set too large, the small amplitude position change will not cause the initial current change of the motor, so the effect of improving the focus speed and accuracy is not obvious; if the jitter threshold is set too small, a small amplitude position change needs to pass. The algorithm calculates the latest motor initial current and changes the parameters of the motor focus algorithm, increasing the focus time and slowing down the focus speed.

(3) Compare the last or previous multiple stable information with the current stable information, and calculate the absolute value of the difference. If the absolute value is less than or equal to the jitter threshold, if it is determined that the device location information has not changed, the focus is calculated using the last calculated focus parameter; if the absolute value is greater than the jitter threshold, it is determined that the device location changes, and the update is issued ( Updata) Command and device current location information.

Step S408. Obtain a corresponding motor initial current according to the location information of the current device.

(1) Set a relationship table between the position information and the initial motor current, or a function relationship between the position information and the initial current of the motor. More precisely, it is necessary to set the maximum and minimum effective range of position information, and set the initial motor current corresponding to the position information outside the effective range, to prevent the condition from crossing the boundary, and the algorithm is confusing.

(2) Calculate the initial motor current using the set relationship table or function relationship based on the current position information.

Step S410. Transfer the initial motor current information to the motor drive.

Step S412. The motor drive feeds back the initial motor current information to the focusing algorithm, and obtains a suitable focusing scheme by using an appropriate algorithm, such as a focus step value and a step_num, and then performs a focusing operation by focusing driving.

In another embodiment, software is also provided for performing the technical solutions described in the above embodiments and preferred embodiments.

In another embodiment, a storage medium is further provided, wherein the software includes the above-mentioned software, including but not limited to: an optical disk, a floppy disk, a hard disk, an erasable memory, and the like.

It will be apparent to those skilled in the art that the various modules or steps of the present invention described above can be implemented by a general-purpose computing device that can be centralized on a single computing device or distributed across a network of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps thereof are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software.

The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Industrial applicability

Claims

A focus control method comprising:

Obtaining the current shooting orientation of the camera;

Determining whether the current shooting orientation is stable;

Obtaining a motor initial current corresponding to the current photographing orientation when determining that the current photographing orientation is stable;

Focusing is performed in accordance with the motor initial current control motor drive.
The method of claim 1, wherein determining whether the current shooting orientation is stable comprises:

Obtaining a difference between the current shooting orientation and a shooting orientation of the first N shots, where N is a natural number not less than 1;

When the absolute values of the M times difference are less than the first preset threshold, it is determined that the current shooting direction is in a stable state; otherwise, the current shooting direction is determined to be in an unstable state, where M≤N.
The method of claim 1, wherein acquiring a motor initial current corresponding to the current photographing orientation comprises:

Comparing whether the current shooting orientation is consistent with one or more stable historical shooting orientations in the history record;

When the judgment result indicates inconsistency, the motor initial current is determined according to the stabilized current photographing orientation.
The method according to claim 3, wherein, when the determination result indicates coincidence, a motor initial current corresponding to the history-capturing orientation is taken as a motor initial current corresponding to the current photographing orientation.
The method of claim 3, wherein determining whether the current shooting orientation is consistent with one or more stabilized historical shooting orientations in the history comprises:

Obtaining an absolute value of a difference between the current shooting orientation and the historical shooting orientation;

When the absolute value of the difference is less than the second preset threshold, determining that the current shooting orientation is consistent with the historical shooting orientation; otherwise, determining that the current shooting orientation is consistent with the historical shooting orientation.
The method according to any one of claims 1 to 5, wherein acquiring a motor initial current corresponding to the current photographing orientation comprises one of the following:

Determining the initial motor current according to a preset correspondence relationship between the shooting orientation and the initial current of the motor;

The motor initial current is determined based on a preset functional relationship between the photographing orientation and the initial motor current.
The method according to any one of claims 1 to 5, wherein the photographing orientation comprises:

The placement position and/or angle of the photographing device at the time of photographing.
A focus control device comprising:

a first acquiring module configured to acquire a current photographing orientation of the photographing device;

a determining module, configured to determine whether the current shooting orientation is stable;

a second acquiring module, configured to acquire a motor initial current corresponding to the current shooting orientation when determining that the current shooting orientation is stable;

The control module is configured to control the motor drive to perform focusing according to the motor initial current.
The device of claim 8, wherein the determining module comprises:

The acquiring unit is configured to obtain a difference between the current shooting orientation and the shooting orientation of the previous N shootings, where N is a natural number not less than 1;

The determining unit is configured to determine that the current shooting direction is in a stable state when the absolute value of the M times difference is less than the first preset threshold, otherwise, determining that the current shooting direction is in an unstable state, wherein M≤ N.
The device according to claim 8, wherein the second obtaining module comprises:

a comparison unit configured to compare whether the current shooting orientation is consistent with one or more stable historical shooting orientations in the history record;

The determining unit is configured to determine the initial motor current according to the stabilized current shooting direction when the determination result indicates inconsistency.
The apparatus according to claim 10, wherein said determining unit is configured to set a motor initial current corresponding to said history-capturing orientation as a motor initial corresponding to said current photographing orientation when said judgment result indication coincides Current.