KR101700195B1 - Mobile terminal and method for controlling thereof - Google Patents

Abstract

The present invention relates to a mobile terminal and a control method thereof, and more particularly, to a mobile terminal using a camera that calculates a straight line distance between a subject and a camera in software and provides an auto focus function quickly, .
A mobile terminal according to an embodiment of the present invention includes a camera capable of changing a focal length and an image capturing unit that extracts feature points of an image when the image including the subject is captured through a camera in a photographing mode and arranges the extracted feature points in a predetermined form, A controller for generating an image frame map, calculating a straight line distance between the subject and the camera using the image frame map, and controlling the camera so that the straight line distance and the focal distance coincide with each other.

Description

[0001] MOBILE TERMINAL AND METHOD FOR CONTROLLING THEREOF [0002]

The present invention relates to a mobile terminal and a control method thereof, and more particularly, to a mobile terminal capable of calculating a straight line distance between a subject and a camera in software and matching the focal distance with a camera quickly, and a control method thereof.

The terminal can move And can be divided into a mobile / portable terminal and a stationary terminal depending on whether the mobile terminal is a mobile terminal or a mobile terminal. The mobile terminal can be divided into a handheld terminal and a vehicle mount terminal according to whether the user can directly carry the mobile terminal.

Such a terminal has various functions, for example, in the form of a multimedia device having multiple functions such as photographing and photographing of a moving picture, reproduction of a music or video file, reception of a game and broadcasting, etc. .

In order to support and enhance the functionality of such terminals, it may be considered to improve the structural and / or software parts of the terminal.

Conventionally, a hardware sensor (an ultrasonic sensor, an infrared sensor, or the like) has been used to provide an auto focus function of a camera, so that it can be implemented only at a relatively expensive terminal, and the straight line distance between the subject and the camera, There is a problem that a certain time is delayed in matching the focal distance, and an improvement plan is required.

It is an object of the present invention to provide a function of calculating a straight line distance between a subject and a camera and matching the focal distance with a camera quickly, .

 It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

According to an aspect of the present invention, there is provided a mobile terminal including a camera capable of changing a focal length and a camera, wherein when an image including a subject is captured through a camera in a shooting mode, Dimensional image frame map to generate a two-dimensional image frame map, calculate a straight line distance between the subject and the camera using the image frame map, and control the camera so that the straight line distance and the focal distance of the camera coincide with each other .

According to an aspect of the present invention, there is provided a method for controlling a mobile terminal, the method including: acquiring an image including a subject through a camera in an imaging mode; extracting the feature points of the image; Dimensional image frame map, calculating a straight line distance between the camera and the subject using the image frame map, and matching the calculated straight line distance with the focal distance of the camera.

The mobile terminal according to at least one embodiment of the present invention configured as described above can acquire an image including a subject through a camera in a photographing mode, extract the feature points of the image, arrange the extracted feature points in a predetermined form, An image frame map is generated and the straight line distance between the subject and the camera is calculated using the image frame map so that the straight line distance and the focal distance of the camera can be matched quickly.

When the difference between the straight line distance and the focal distance deviates from a preset threshold distance by changing the position of at least one of the camera and the subject after the straight line distance between the subject and the camera matches the focal distance of the camera, And the focal distance is shifted by a distance deviated from the acquired image again to provide convenience to the user by re-focusing the focus.

The effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description will be.

1 is a block diagram of a mobile terminal according to an embodiment of the present invention.
2 is a front perspective view of a mobile terminal according to an embodiment of the present invention;
3 is a front view of a mobile terminal for explaining an operation state of the mobile terminal according to the present invention;
4 is a flowchart showing an example of providing an auto focus function in a mobile terminal according to an embodiment of the present invention;
5 illustrates an example of generating a two-dimensional image frame by extracting feature points of an image according to an embodiment of the present invention.
Figure 6 is a flow diagram further comprising, in accordance with another embodiment of the present invention, further refocusing when the difference in linear distance and focal distance in Figure 4 deviates from a preset threshold distance.
7A to 7C illustrate a process of recognizing a selected point as a subject when a specific point is selected in a preview image according to another embodiment of the present invention.

Hereinafter, a mobile terminal related to the present invention will be described in detail with reference to the drawings. The suffix "module" and " part "for the components used in the following description are given or mixed in consideration of ease of specification, and do not have their own meaning or role.

The mobile terminal described in this specification may include a mobile phone, a smart phone, a laptop computer, a digital broadcasting terminal, a PDA (Personal Digital Assistants), a PMP (Portable Multimedia Player), navigation and the like. However, it will be understood by those skilled in the art that the configuration according to the embodiments described herein may be applied to a fixed terminal such as a digital TV, a desktop computer, and the like, unless the configuration is applicable only to a mobile terminal.

1 is a block diagram of a mobile terminal according to an embodiment of the present invention.

The mobile terminal 100 includes a wireless communication unit 110, an audio / video input unit 120, a user input unit 130, a sensing unit 140, an output unit 150, a memory 160, A controller 170, a controller 180, a power supply 190, and the like. The components shown in FIG. 1 are not essential, and a mobile terminal having more or fewer components may be implemented.

Hereinafter, the components will be described in order.

The wireless communication unit 110 may include one or more modules for enabling wireless communication between the mobile terminal 100 and the wireless communication system or between the mobile terminal 100 and the network in which the mobile terminal 100 is located. For example, the wireless communication unit 110 may include a broadcast receiving module 111, a mobile communication module 112, a wireless Internet module 113, a short range communication module 114, and a location information module 115 .

The broadcast receiving module 111 receives broadcast signals and / or broadcast-related information from an external broadcast management server through a broadcast channel.

The broadcast channel may include a satellite channel and a terrestrial channel. The broadcast management server may refer to a server for generating and transmitting broadcast signals and / or broadcast related information, or a server for receiving broadcast signals and / or broadcast related information generated by the broadcast management server and transmitting the generated broadcast signals and / or broadcast related information. The broadcast signal may include a TV broadcast signal, a radio broadcast signal, a data broadcast signal, and a broadcast signal in which a data broadcast signal is combined with a TV broadcast signal or a radio broadcast signal.

The broadcast-related information may refer to a broadcast channel, a broadcast program, or information related to a broadcast service provider. The broadcast-related information may also be provided through a mobile communication network. In this case, it may be received by the mobile communication module 112.

The broadcast-related information may exist in various forms. For example, an EPG (Electronic Program Guide) of DMB (Digital Multimedia Broadcasting) or an ESG (Electronic Service Guide) of Digital Video Broadcast-Handheld (DVB-H).

For example, the broadcast receiving module 111 may be a Digital Multimedia Broadcasting-Terrestrial (DMB-T), a Digital Multimedia Broadcasting-Satellite (DMB-S), a Media Forward Link Only And a Digital Broadcasting System (ISDB-T) (Integrated Services Digital Broadcast-Terrestrial). Of course, the broadcast receiving module 111 may be adapted to other broadcasting systems as well as the digital broadcasting system described above.

The broadcast signal and / or broadcast related information received through the broadcast receiving module 111 may be stored in the memory 160.

The mobile communication module 112 transmits and receives radio signals to at least one of a base station, an external terminal, and a server on a mobile communication network. The wireless signal may include various types of data depending on a voice call signal, a video call signal or a text / multimedia message transmission / reception.

The wireless Internet module 113 is a module for wireless Internet access, and may be built in or externally attached to the mobile terminal 100. WLAN (Wi-Fi), Wibro (Wireless broadband), Wimax (World Interoperability for Microwave Access), HSDPA (High Speed Downlink Packet Access) and the like can be used as wireless Internet technologies.

The short-range communication module 114 refers to a module for short-range communication. Bluetooth, Radio Frequency Identification (RFID), infrared data association (IrDA), Ultra Wideband (UWB), ZigBee, and the like can be used as a short range communication technology.

The position information module 115 is a module for obtaining the position of the mobile terminal, and a representative example thereof is a Global Position System (GPS) module.

Referring to FIG. 1, an A / V (Audio / Video) input unit 120 is for inputting an audio signal or a video signal, and may include a camera 121 and a microphone 122. The camera 121 processes image frames such as still images or moving images obtained by the image sensor in the video communication mode or the photographing mode. The processed image frame can be displayed on the display unit 151. [

The image frame processed by the camera 121 may be stored in the memory 160 or transmitted to the outside through the wireless communication unit 110. [ Two or more cameras 121 may be provided depending on the use environment.

The camera 121 may include a focal length moving unit capable of changing a focal length of the lens, a motor for providing power to the focal length moving unit, and the like, Lt; / RTI >

The microphone 122 receives an external sound signal through a microphone in a communication mode, a recording mode, a voice recognition mode, or the like, and processes it as electrical voice data. The processed voice data can be converted into a form that can be transmitted to the mobile communication base station through the mobile communication module 112 when the voice data is in the call mode, and output. Various noise reduction algorithms may be implemented in the microphone 122 to remove noise generated in receiving an external sound signal.

The user input unit 130 generates input data for a user to control the operation of the terminal. The user input unit 130 may include a key pad dome switch, a touch pad (static / static), a jog wheel, a jog switch, and the like.

The sensing unit 140 senses the current state of the mobile terminal 100 such as the open / close state of the mobile terminal 100, the position of the mobile terminal 100, the presence or absence of user contact, the orientation of the mobile terminal, And generates a sensing signal for controlling the operation of the mobile terminal 100. For example, when the mobile terminal 100 is in the form of a slide phone, it is possible to sense whether the slide phone is opened or closed. It is also possible to sense whether the power supply unit 190 is powered on, whether the interface unit 170 is connected to an external device, and the like. Meanwhile, the sensing unit 140 may include an infrared sensor, and the infrared sensor may be used to calculate a straight line distance between the subject and the camera in order to supplement the auto focus function.

The output unit 150 is for generating an output relating to visual, auditory or tactile sense and includes a display unit 151, an acoustic output module 152, an alarm unit 153, a haptic module 154, 155, and the like.

The display unit 151 displays (outputs) information processed by the mobile terminal 100. For example, when the mobile terminal is in the call mode, a UI (User Interface) or a GUI (Graphic User Interface) associated with a call is displayed. When the mobile terminal 100 is in the video communication mode or the photographing mode, the photographed and / or received video or UI and GUI are displayed.

The display unit 151 may be a liquid crystal display (LCD), a thin film transistor-liquid crystal display (TFT LCD), an organic light-emitting diode (OLED), a flexible display display, and a 3D display.

Some of these displays may be transparent or light transmissive so that they can be seen through. This can be referred to as a transparent display, and a typical example of the transparent display is TOLED (Transparent OLED) and the like. The rear structure of the display unit 151 may also be of a light transmission type. With this structure, the user can see an object located behind the terminal body through the area occupied by the display unit 151 of the terminal body.

There may be two or more display units 151 according to the embodiment of the mobile terminal 100. For example, in the mobile terminal 100, a plurality of display portions may be spaced apart from one another or may be disposed integrally with each other, or may be disposed on different surfaces.

(Hereinafter, referred to as a 'touch screen') in which a display unit 151 and a sensor for sensing a touch operation (hereinafter, referred to as 'touch sensor') form a mutual layer structure, It can also be used as an input device. The touch sensor may have the form of, for example, a touch film, a touch sheet, a touch pad, or the like.

The touch sensor may be configured to convert a change in a pressure applied to a specific portion of the display unit 151 or a capacitance generated in a specific portion of the display unit 151 into an electrical input signal. The touch sensor can be configured to detect not only the position and area to be touched but also the pressure at the time of touch.

If there is a touch input to the touch sensor, the corresponding signal (s) is sent to the touch controller. The touch controller processes the signal (s) and transmits the corresponding data to the controller 180. Thus, the control unit 180 can know which area of the display unit 151 is touched or the like.

The proximity sensor 141 may be disposed in an inner region of the mobile terminal or in the vicinity of the touch screen, which is enclosed by the touch screen. The proximity sensor refers to a sensor that detects the presence or absence of an object approaching a predetermined detection surface or a nearby object without mechanical contact using the force of an electromagnetic field or infrared rays. The proximity sensor has a longer life span than the contact sensor and its utilization is also high.

Examples of the proximity sensor include a transmission type photoelectric sensor, a direct reflection type photoelectric sensor, a mirror reflection type photoelectric sensor, a high frequency oscillation type proximity sensor, a capacitive proximity sensor, a magnetic proximity sensor, and an infrared proximity sensor. And to detect the proximity of the pointer by the change of the electric field along the proximity of the pointer when the touch screen is electrostatic. In this case, the touch screen (touch sensor) may be classified as a proximity sensor.

Hereinafter, for convenience of explanation, the act of recognizing that the pointer is positioned on the touch screen while the pointer is not in contact with the touch screen is referred to as "proximity touch & The act of actually touching the pointer on the screen is called "contact touch. &Quot; The position where the pointer is proximately touched on the touch screen means a position where the pointer is vertically corresponding to the touch screen when the pointer is touched.

The proximity sensor detects a proximity touch and a proximity touch pattern (e.g., a proximity touch distance, a proximity touch direction, a proximity touch speed, a proximity touch time, a proximity touch position, a proximity touch movement state, and the like). Information corresponding to the detected proximity touch operation and the proximity touch pattern may be output on the touch screen.

The audio output module 152 may output audio data received from the wireless communication unit 110 or stored in the memory 160 in a call signal reception mode, a call mode or a recording mode, a voice recognition mode, a broadcast reception mode, The sound output module 152 also outputs sound signals related to functions (e.g., call signal reception sound, message reception sound, etc.) performed in the mobile terminal 100. [ The audio output module 152 may include a receiver, a speaker, a buzzer, and the like.

The alarm unit 153 outputs a signal for notifying the occurrence of an event of the mobile terminal 100. Examples of events that occur in the mobile terminal include call signal reception, message reception, key signal input, touch input, and the like. The alarm unit 153 may output a signal for notifying the occurrence of an event in a form other than the video signal or the audio signal, for example, vibration. The video signal or the audio signal may be output through the display unit 151 or the audio output module 152 so that they may be classified as a part of the alarm unit 153.

The haptic module 154 generates various tactile effects that the user can feel. A typical example of the haptic effect generated by the haptic module 154 is vibration. The intensity and pattern of the vibration generated by the hit module 154 can be controlled. For example, different vibrations may be synthesized and output or sequentially output.

In addition to the vibration, the haptic module 154 may include a pin arrangement vertically moving with respect to the contact skin surface, a spraying force or a suction force of the air through the injection port or the suction port, a touch on the skin surface, contact with an electrode, And various tactile effects such as an effect of reproducing a cold sensation using an endothermic or exothermic element can be generated.

The haptic module 154 can be implemented not only to transmit the tactile effect through the direct contact but also to allow the user to feel the tactile effect through the muscular sensation of the finger or arm. The haptic module 154 may include two or more haptic modules 154 according to the configuration of the portable terminal 100.

The projector module 155 is a component for performing an image project function using the mobile terminal 100 and is similar to the image displayed on the display unit 151 in accordance with a control signal of the controller 180 Or at least partly display another image on an external screen or wall.

Specifically, the projector module 155 includes a light source (not shown) that generates light (for example, laser light) for outputting an image to the outside, a light source And a lens (not shown) for enlarging and outputting the image at a predetermined focal distance to the outside. Further, the projector module 155 may include a device (not shown) capable of mechanically moving the lens or the entire module to adjust the image projection direction.

The projector module 155 can be divided into a CRT (Cathode Ray Tube) module, an LCD (Liquid Crystal Display) module and a DLP (Digital Light Processing) module according to the type of the display means. In particular, the DLP module may be advantageous for miniaturization of the projector module 151 by enlarging and projecting an image generated by reflecting light generated from a light source on a DMD (Digital Micromirror Device) chip.

Preferably, the projector module 155 may be provided longitudinally on the side, front or back side of the mobile terminal 100. It goes without saying that the projector module 155 may be provided at any position of the mobile terminal 100 as occasion demands.

The memory unit 160 may store a program for processing and controlling the control unit 180 and temporarily store the input / output data (e.g., telephone directory, message, audio, For example. The memory unit 160 may also store the frequency of use of each of the data (for example, each telephone number, each message, and frequency of use for each multimedia). In addition, the memory unit 160 may store data on vibration and sound of various patterns output when the touch is input on the touch screen.

The memory 160 may be a flash memory type, a hard disk type, a multimedia card micro type, a card type memory (for example, SD or XD memory), a RAM (Random Access Memory), SRAM (Static Random Access Memory), ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), PROM A disk, and / or an optical disk. The mobile terminal 100 may operate in association with a web storage that performs a storage function of the memory 160 on the Internet.

The interface unit 170 serves as a path for communication with all external devices connected to the mobile terminal 100. The interface unit 170 receives data from an external device or supplies power to each component in the mobile terminal 100 or transmits data to the external device. For example, a wired / wireless headset port, an external charger port, a wired / wireless data port, a memory card port, a port for connecting a device having an identification module, an audio I / O port, A video input / output (I / O) port, an earphone port, and the like may be included in the interface unit 170.

The identification module is a chip for storing various information for authenticating the use right of the mobile terminal 100 and includes a user identification module (UIM), a subscriber identity module (SIM), a general user authentication module A Universal Subscriber Identity Module (USIM), and the like. Devices with identification modules (hereinafter referred to as "identification devices") can be manufactured in a smart card format. Accordingly, the identification device can be connected to the terminal 100 through the port.

When the mobile terminal 100 is connected to an external cradle, the interface unit may be a path through which power from the cradle is supplied to the mobile terminal 100, or various command signals input by the user to the cradle may be transmitted It can be a passage to be transmitted to the terminal. The various command signals or the power source input from the cradle may be operated as a signal for recognizing that the mobile terminal is correctly mounted on the cradle.

The controller 180 typically controls the overall operation of the mobile terminal. For example, voice communication, data communication, video communication, and the like. The control unit 180 may include a multimedia module 181 for multimedia playback. The multimedia module 181 may be implemented in the control unit 180 or may be implemented separately from the control unit 180. [

The controller 180 may perform a pattern recognition process for recognizing handwriting input or drawing input performed on the touch screen as characters and images, respectively.

Also, the controller 180 may control the linear distance between the camera 121 and the subject to match the focal distance of the camera 121.

The power supply unit 190 receives external power and internal power under the control of the controller 180 and supplies power necessary for operation of the respective components.

The various embodiments described herein may be embodied in a recording medium readable by a computer or similar device using, for example, software, hardware, or a combination thereof.

According to a hardware implementation, the embodiments described herein may be implemented as application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays May be implemented using at least one of a processor, controllers, micro-controllers, microprocessors, and other electronic units for performing other functions. In some cases, The embodiments described may be implemented by the control unit 180 itself.

According to a software implementation, embodiments such as the procedures and functions described herein may be implemented with separate software modules. Each of the software modules may perform one or more of the functions and operations described herein. Software code can be implemented in a software application written in a suitable programming language. The software code is stored in the memory 160 and can be executed by the control unit 180. [

FIG. 2 is a perspective view of a mobile terminal or a portable terminal according to the present invention, as viewed from the front.

The disclosed mobile terminal 100 has a bar-shaped terminal body. However, the present invention is not limited thereto, and can be applied to various structures such as a slide type, a folder type, a swing type, and a swivel type in which two or more bodies are relatively movably coupled.

The body includes a case (a casing, a housing, a cover, and the like) which forms an appearance. In this embodiment, the case may be divided into a front case 101 and a rear case 102. [ A variety of electronic components are embedded in the space formed between the front case 101 and the rear case 102. At least one intermediate case may be additionally disposed between the front case 101 and the rear case 102. [

The cases may be formed by injection molding a synthetic resin, or may be formed to have a metal material such as stainless steel (STS) or titanium (Ti) or the like.

The display unit 151, the sound output unit 152, the camera 121, the user input units 130/131 and 132, the microphone 122, the interface 170, and the like may be disposed in the front body 101 have.

The display unit 151 occupies most of the main surface of the front case 101. A sound output unit 151 and a camera 121 are disposed in an area adjacent to one end of both ends of the display unit 151 and a user input unit 131 and a microphone 122 are disposed in an area adjacent to the other end. The user input unit 132 and the interface 170 may be disposed on the side surfaces of the front case 101 and the rear case 102. [

The user input unit 130 is operated to receive a command for controlling the operation of the portable terminal 100 and may include a plurality of operation units 131 and 132. The operation units 131 and 132 may be collectively referred to as a manipulating portion and may be employed in any manner as long as the user operates in a tactile manner.

The contents inputted by the first or second operation unit 131 or 132 may be variously set. For example, the first operation unit 131 receives commands such as start, end, scroll, and the like, and the second operation unit 132 controls the size of the sound output from the sound output unit 152 or the size of the sound output from the display unit 151 To the touch recognition mode of the touch screen.

In addition to the antenna for talking and the like, a broadcast signal receiving antenna 116 may be further disposed on the side of the terminal body. The antenna 116, which forms part of the broadcast receiving module 111 (see FIG. 1), can be installed to be able to be drawn out from the terminal body.

A power supply unit 190 for supplying power to the portable terminal 100 is mounted on the terminal body. The power supply unit 190 may be built in the terminal body or may be detachable from the outside of the terminal body.

The rear case 102 may further include a touch pad 135 for sensing a touch. The touch pad 135 may also be of a light transmission type like the display unit 151. [ In this case, if the display unit 151 is configured to output time information on both sides, the time information can be recognized through the touch pad 135 as well. The information output on both sides may be all controlled by the touch pad 135. [ Alternatively, a display may be additionally mounted on the touch pad 135, and a touch screen may be disposed on the rear case 102 as well.

Hereinafter, a related operation of the display unit 151 and the touch pad 135 will be described with reference to FIG.

3 is a front view of a portable terminal for explaining an operation state of the portable terminal according to the present invention.

Various types of time information can be displayed on the display unit 151. [ These pieces of information can be displayed in the form of letters, numbers, symbols, graphics, or icons.

At least one of the letters, numbers, symbols, graphics, or icons may be displayed in a predetermined arrangement for inputting such information, thereby being implemented as a keypad. Such a keypad may be referred to as a so-called " virtual keypad ".

3 illustrates inputting of a touch applied to the virtual keypad through the front surface of the terminal body.

The display unit 151 may operate as an entire area or may be divided into a plurality of areas and operated. In the latter case, the plurality of areas can be configured to operate in association with each other.

For example, an output window 151a and an input window 151b are displayed on the upper and lower portions of the display unit 151, respectively. The output window 151a and the input window 151b are areas allocated for outputting or inputting information, respectively. In the input window 151b, a virtual keypad 151c is displayed in which a number for inputting a telephone number or the like is displayed. When the virtual keypad 151c is touched, numbers and the like corresponding to the touched virtual keypad are displayed on the output window 151a. When the first operation unit 131 is operated, call connection to the telephone number displayed on the output window 151a is attempted.

The display unit 151 or the touch pad 135 may be configured to receive a touch input by scrolling, as well as the input method described in the above embodiments. The user can move a cursor or a pointer located on an object displayed on the display unit 151, for example, an icon or the like, by scrolling the display unit 151 or the touch pad 135. [ Further, when the finger is moved on the display portion 151 or the touch pad 135, the path along which the finger moves may be visually displayed on the display portion 151. [ This will be useful for editing the image displayed on the display unit 151. [

One function of the terminal may be executed in response to a case where the display unit 151 (touch screen) and the touch pad 135 are touched together within a predetermined time range. In the case of being touched together, there may be a case where the user clamps the terminal body using the thumb and index finger. The one function may be activation or deactivation of the display unit 151 or the touch pad 135, for example.

For convenience of explanation, it is assumed that the mobile terminal referred to below includes at least one of the components shown in FIG.

Also, an arrow or finger-shaped graphic for pointing a specific object or selecting a menu on the display unit 151 is called a pointer or a cursor.

However, in the case of a pointer, it often means a finger or a stylus pen for a touch operation or the like.

Therefore, in this specification, a graphic displayed on the display unit 151 is referred to as a cursor and a physical means for performing a touch, a proximity touch, and a gesture such as a finger or a stylus pen is referred to as a pointer It is called.

1st Example

According to an embodiment of the present invention, the mobile terminal 100 may calculate the straight line distance between the camera 121 and the subject by software so that the straight line distance and the focal distance of the camera coincide with each other

The auto-focus function refers to the function of the camera 121 to automatically match the straight line distance between the subject to be photographed and the camera 121 and the focal distance of the camera 121.

In general, when providing the auto-focus function, the camera 121 measures the intensity of infrared rays reflected from the object using an infrared sensor or measures the time of infrared rays reflected from the object to calculate a straight line distance to the object , A hardware method of matching the straight line distance with the focal distance of the camera 121 is used.

Recently, it has become possible to perform a high degree of computation according to the dramatic performance improvement of the processor of the mobile terminal 100, that is, the control unit 180. The straight line distance to the subject is calculated by a software method rather than a hardware method, A matching method is possible. Hereinafter, a method of providing a software auto focus function according to an embodiment of the present invention will be described in detail with reference to FIG.

4 is a flowchart illustrating an example of providing an auto focus function in the mobile terminal 100 according to an embodiment of the present invention.

4, an image including the subject can be obtained through the camera 121 when the photographing mode is entered (S410).

The acquired image can be displayed through the display unit 151 as a preview image.

The controller 180 may extract the feature points of the acquired image to generate a two-dimensional image frame (S420).

In order to generate an image frame, the control unit can create a map having coordinate axes of two dimensions (for example, X axis, Y axis, etc.).

The map can be divided into a plurality of unit areas by being divided into a plurality of two-dimensional coordinates.

The map may be all or part of a preview image displayed through the display unit 151, and a plurality of unit areas constituting the map may be changed according to the range of the map.

The feature points of the image obtained based on the map can be extracted and generated as a two-dimensional image frame.

The minutiae points of the image may be the points where the subject included in the acquired image meets the two-dimensional coordinates of the plurality of unit areas.

When feature points for a plurality of subjects are extracted and displayed on a map, a step of generating a two-dimensional image frame is completed.

The image frame generating step S420 will be described in more detail with reference to FIG.

FIG. 5 illustrates an example of a step of generating a two-dimensional image frame.

A map having two-dimensional coordinate axes in FIG. 5 is a part of a preview image to be displayed, and is divided into a unit area of 10 X 10.

The subjects included in the obtained image are both located in the two-dimensional image frame by the eraser 511 and the highlight pen 512. [

A point where the eraser 511 and the highlight pen 512 meet with the unit area can be minutiae points, and a plurality of minutiae points are displayed on a map to be represented by a two-dimensional image frame. A straight line distance between the camera and the subject can be calculated based on the minutiae points, and details thereof will be described later.

4, when the two-dimensional image frame is generated, the controller 180 may calculate the straight line distance between the subject and the camera 121 using the image frame (S430).

A method of calculating the straight line distance between the subject and the camera 121 will be described in more detail.

Each unit area in the plurality of unit areas constituting the image frame has a predetermined unit distance.

The number of unit areas existing up to the unit area including the feature points of the subject is calculated based on the lowermost end of the preview image displayed through the display unit 151. When the number of unit areas is multiplied by a predetermined unit distance, And the straight line distance between the camera and the camera can be calculated.

The unit distance can be changed according to the position of the subject, and it is possible to calculate the straight line distance between the camera 121 and the subject by analyzing the feature points expressed in the two-dimensional image frame map.

Various algorithms can be applied in relation to the method of calculating the straight line distance between the subject and the camera. However, since parallel tracking and mapping technology can be typically applied, a parallel tracking and mapping ) Technology will be described in detail.

The mapping records the structure of the space that is viewed through the camera 121 and analyzes the images obtained through the camera 121 to detect feature points that are essential for image processing, And the description thereof is omitted. However, for the sake of simplicity of the description, redundant description will be omitted.

Tracking is a process of tracking the current position of the camera 121 and representing augmented graphic, thereby calculating a reference point of the current position in order to calculate an accurate straight line distance from the subject.

In general, the tracking and mapping processes are sequentially performed. In contrast, the mapping does not change greatly every frame, whereas the tracking process continuously detects the position of the camera 121 and updates the map (Degree of Freedom) is required. Therefore, there is a problem in that it is costly and requires an intermittent map.

Parallel Tracking And Mapping technology is designed to create a dense map with low-quality feature points to solve the above problems.

 The tracking is performed at every frame without updating, and only the frames from which the minutiae are extracted are selected as the key frames, and the mapping process that does not change greatly every frame and the tracking process that must be performed quickly and quickly are simultaneously processed.

Thereby, the linear distance between the camera 121 and the subject can be calculated quickly, and the price of the mobile terminal 100 can be lowered.

Referring back to FIG. 4, when the straight line distance between the subject and the camera 121 is calculated, the controller 180 can adjust the focal distance of the camera 121 and the straight line distance through the auto focus module provided in the camera (S440).

Then, the photographing can be performed in a state in which the camera is focused (S450). The shooting is generally performed by a method of operating the shutter button. Here, the shutter button may be a hardware key button, or may be a virtual key button when a touch screen is provided.

The user input unit 130 corresponding to the shutter function is operated to take a photograph, and the photographed image can be stored in the memory 160 (S460).

Second Example

According to another embodiment of the present invention, when the camera is not in focus due to the movement of the subject or the camera after focusing, it is possible to provide a function of moving the focal distance by an offset distance and refocusing the camera.

In general, when the position of the camera 121 and / or the subject is changed to deviate from a previously focused focus, a process of adjusting the changed focal distance must be newly performed.

The focal length of the camera 121 may vary depending on the characteristics of the lens constituting the camera, and there is a critical distance that the camera can see as being focused (i.e., the subject is clearly visible).

For example, when the straight line distance between the camera 121 and the subject is 1M, if the lens that is considered to be in focus from -20Cm to +20Cm is applied to the camera 121, the critical distance will be 20Cm.

In this case, when the user manually operates the above process, the user may be inconvenienced and a time delay may occur. Therefore, a process of automatically adjusting the focus of the camera is required. Will be specifically described below.

6 is a flowchart further comprising a step of newly adjusting a focus when a difference between a straight line distance and a focal length is out of a predetermined threshold distance in FIG.

S610 through S640 are similar to steps S410 through S440 of FIG. 4, and steps S660 and S670 are similar to steps S450 and S460 of FIG. 4, respectively, so that redundant description is omitted for clarity of description do.

When the straight line distance between the subject and the camera 121 is equal to the focal length of the camera in step S640 and the difference between the straight line distance and the focal length is out of the threshold distance set in the controller 180, And the focal distance is shifted by an offset distance so that the camera 121 can be refocused (S650).

The critical distance according to the lens may be determined in advance and set in advance in the controller 180.

Whether or not the difference between the straight line distance and the focal distance between the camera 121 and the subject is out of the critical distance can be judged by applying the above-described parallel tracking and mapping technique.

The determination may be made through an infrared sensor. When the difference between the straight line distance between the camera 121 and the subject and the focal distance deviates from the critical distance, the infrared sensor may notify the control unit 180 of the content.

The controller 180 uses the parallel tracking and mapping technique or detects the sensing signal to acquire an image including the subject through the camera and moves the focal distance by an offset distance to newly acquire the image of the camera You will be able to focus on the initiative.

Third Example

Meanwhile, according to another embodiment of the present invention, when the preview image is displayed on the display unit 151, the user can change the object (or area) to be focused by selecting an arbitrary point.

In general, when an image including objects is acquired through the camera 121, the center of the acquired image is used as a reference, or a predetermined area is divided in advance, and a focus is set on the basis of a subject included in the area It is tailored.

However, when the user views the preview image on the display unit 151 and wants to change a subject to be focused or select a specific point, a method of changing the focused focus is required. The process of selecting and focusing is described in detail with reference to Figs. 7A to 7C.

7A to 7C are views for explaining a process of recognizing a specific point selected as a subject when a specific point is selected in the preview image.

Hereinafter, it is assumed that the display unit 151 is a touch screen, and a default focus setting of the camera is applied so as to focus on a subject positioned in the center.

7A, three different subjects 710, 720, and 730 are displayed on the display unit 151 as a preview image input through the camera 121. FIG. More specifically, according to the default setting, the subject 720 located in the center of the preview image is focused, and the focused subject 720 on the display unit is displayed clearly but the remaining subjects 710 and 730 It is displayed blurred.

At this time, the user can touch the desired subject 710 with a finger as shown in FIG. 7B to focus on another object (here, 710).

7C, the focus of the camera can be adjusted to the subject 710 of the selected specific point, the selected subject 710 is displayed clearly on the display portion, and the remaining other subjects 720 and 730 are blurred Lt; / RTI >

Accordingly, the user can focus the camera on the arbitrarily selected subject 710 and take a picture.

In FIG. 7, a touch using a finger is used as a method for changing an object to be focused. However, the present invention is not limited thereto. For example, the object to be focused can be changed in various ways. For example, a cursor that can be controlled by operation through the user input unit 130 may be used in addition to a pointer such as a finger or a stylus pen.

Further, according to an embodiment of the present invention, the above-described method can be implemented as a code that can be read by a processor on a medium on which the program is recorded. Examples of the medium that can be read by the processor include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, etc., and may be implemented in the form of a carrier wave (e.g., transmission over the Internet) .

The mobile terminal described above can be applied to not only the configuration and method of the embodiments described above but also all or some of the embodiments may be selectively combined so that various modifications may be made to the embodiments It is possible.

Claims (5)

A camera whose focal length can be changed; And
When an image including a subject is obtained through the camera in the photographing mode, extracting the feature points of the image, arranging the extracted feature points in a predetermined form to generate a two-dimensional image frame map, And a control unit for calculating the straight line distance between the subject and the camera and controlling the camera so that the straight line distance and the focal distance coincide with each other,
The control unit
Wherein the calculation of the straight line distance is performed through a parallel tracking and mapping technique. The method according to claim 1,
When the difference between the straight line distance and the focal distance deviates from a predetermined threshold distance in accordance with a change in position of at least one of the camera and the subject after the straight line distance and the focal distance match,
Wherein,
Calculating a straight line distance between the subject and the camera from the re-acquired image, calculating a straight line distance between the subject and the camera using the camera, And a control unit for controlling the mobile terminal. delete The method according to claim 1,
A display unit for displaying at least a part of the image input through the camera as a preview image; And
Further comprising a user input unit for receiving a command of a user,
Wherein,
Wherein when the preview image is displayed on the display unit, a specific point is selected as an input through the user input unit, the selected point is recognized as the subject. Acquiring an image including a subject through a camera in a shooting mode;
Extracting feature points of the image and creating a two-dimensional image frame map in which the extracted feature points are arranged in a predetermined form;
Calculating a straight line distance between the camera and the subject using the image frame map; calculating a straight line distance between the camera and the subject through a parallel tracking and mapping technique; And
And matching the calculated straight line distance with the focal distance of the camera.

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