Patent Publication Number: US-2013242167-A1

Title: Apparatus and method for capturing image in mobile terminal

Description:
PRIORITY 
     This application claims the benefit under 35 U.S.C. §119(a) of a Korean patent application filed in the Korean Intellectual Property Office on Mar. 14, 2012 and assigned Serial No. 10-2012-0025923, the entire disclosure of which is hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus and method for capturing images in a mobile terminal More particularly, the present invention relates to an image capturing apparatus and method capable of capturing images that have undergone Auto Focus (AF), in a mobile terminal. 
     2. Description of the Related Art 
     In mobile terminals, a method for focusing a subject while capturing an image may be classified into Auto Focus (AF) and Fixed Focus (FF). There are several methods for capturing images after performing AF. The most typical method is to perform AF by entering a half shutter and then capturing or photographing a subject by entering a full shutter, using a separate camera hard key or a soft key (e.g., User Interface (UI)) displayed on a camera-mode screen. 
     Another typical method is to apply Continuous Auto Focus (CAF) that continuously performs AF in a preview mode depending on changes in the screen, and captures a subject at the time the user selects an entry or an input by pressing a button short or long. When performing CAF in a preview mode, a mobile terminal with a camera runs preview in a full frame to match with a resolution of the camera, and performs AF in accordance with its AF algorithm, making it possible to maintain the focus by continuously moving the lens no matter what change may occur on the screen. 
     If the user enters his or her intention to capture the current preview screen with a hard key or a soft key of the mobile terminal while CAF is performed in the preview mode, the screen will be immediately captured. However, if a ‘capture’ entry is selected by the user before the AF is not completely performed yet or while the lens is still moving for focusing, due to the rapid screen switching for example, then images that have not undergone AF may be captured, causing a decrease in confidence of best focusing. 
     The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention. 
     SUMMARY OF THE INVENTION 
     Aspects of the present invention are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide an image capturing apparatus and method capable of capturing images that have undergone AF, depending on the user&#39;s entry in a mobile terminal. 
     In accordance with an aspect of the present invention, an apparatus for capturing an image in a mobile terminal is provided. The apparatus includes a camera module, and a controller for determining whether a captured frame has undergone Auto Focus (AF) if a ‘capture’ entry is selected while performing Continuous Auto Focus (CAF) in a preview mode, and for performing AF on the captured frame if the captured frame has not undergone AF. 
     In accordance with another aspect of the present invention, an apparatus for capturing an image in a mobile terminal is provided. The apparatus includes a camera module, and a controller for determining whether a captured frame has undergone AF if a ‘capture’ entry is selected while performing CAF in a preview mode, and for automatically switching to the preview mode where CAF is performed, if the captured frame has not undergone AF. 
     In accordance with another aspect of the present invention, an apparatus for capturing an image in a mobile terminal is provided. The apparatus includes a camera module, and a controller for determining whether a captured frame has undergone AF if a ‘capture’ entry is selected while performing CAF in a preview mode, and for displaying the captured frame before storage thereof, if the captured frame has not undergone AF. 
     In accordance with another aspect of the present invention, an apparatus for capturing an image in a mobile terminal is provided. The apparatus includes a camera module, and a controller for determining whether a previously captured frame has undergone AF in a preview mode where CAF is performed, and for indicating that the previously captured frame has not undergone AF, if the previously captured frame has not undergone AF. 
     In accordance with another aspect of the present invention, a method for capturing an image in a mobile terminal is provided. The method includes determining whether a captured frame has undergone AF, if a ‘capture’ entry is selected while performing CAF in a preview mode; and performing AF on the captured frame if the captured frame has not undergone AF. 
     In accordance with another aspect of the present invention, a method for capturing an image in a mobile terminal is provided. The method includes determining whether a captured frame has undergone AF, if a ‘capture’ entry is selected while performing CAF in a preview mode, and automatically switching to the preview mode where CAF is performed, if the captured frame has not undergone AF. 
     In accordance still another aspect of the present invention, a method for capturing an image in a mobile terminal is provided. The method includes determining whether a captured frame has undergone AF, if a ‘capture’ entry is selected while performing CAF in a preview mode, and displaying the captured frame before storage thereof, if the captured frame has not undergone AF. 
     In accordance with another aspect of the present invention, a method for capturing an image in a mobile terminal is provided. The method includes determining whether a previously captured frame has undergone AF in a preview mode where CAF is performed, and indicating that the previously captured frame has not undergone AF in the preview mode, if the previously captured frame has not undergone AF. 
     Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a block diagram showing a structure of a mobile terminal according to an exemplary embodiment of the present invention; 
         FIG. 2  is a flowchart showing a process of capturing images in a mobile terminal according to a first exemplary embodiment of the present invention; 
         FIG. 3  is a flowchart showing a process of capturing images in a mobile terminal according to a second exemplary embodiment of the present invention; 
         FIG. 4  is a flowchart showing a process of capturing images in a mobile terminal according to a third exemplary embodiment of the present invention; and 
         FIG. 5  is a flowchart showing a process of capturing images in a mobile terminal according to a fourth exemplary embodiment of the present invention. 
     
    
    
     Throughout the drawings, the same drawing reference numerals will be understood to refer to the same elements, features and structures. 
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding, but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness. 
     The terms and words used in the following description and claims are not limited to the bibliographical meanings, but are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention is provided for illustration purposes only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. 
     It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces. 
       FIG. 1  shows a structure of a mobile terminal according to an exemplary embodiment of the present invention. 
     Referring to  FIG. 1 , a Radio Frequency (RF) unit  123  is responsible for radio communication in the mobile terminal The RF unit  123  includes an RF transmitter for up-converting a frequency of transmission signals and amplifying the up-converted transmission signals, and an RF receiver for low-noise-amplifying received signals and down-converting a frequency of the amplified received signals. A data processor  120  includes a transmitter for coding and modulating the transmission signals, and a receiver for demodulating and decoding the received signals. The data processor  120  may include a modulator/demodulator (modem) and a coder/decoder (codec). The codec includes a data codec for processing data signals such as packet data, and an audio codec for processing audio signals such as voice. An audio processor  125  plays received audio signals output from the audio codec in the data processor  120  using a speaker SPK, and transfers transmission audio signals picked up by a microphone MIC to the audio codec in the data processor  120 . 
     A key input unit  127  includes alphanumerical keys for inputting alphanumerical information and function keys for setting various functions. 
     A memory  130  may include a program memory and a data memory. The program memory may store programs for controlling the general operation of the mobile terminal, and programs for performing Auto Focus (AF) on a captured frame, automatically switching to a preview mode where Continuous Auto Focus (CAF) is performed, and/or displaying the captured frame before storage thereof, depending on a change in motion of the frame captured while performing CAF in the preview mode. The data memory temporarily stores the data generated during execution of these programs. The memory  130  stores frames that have continuously undergone AF depending on the change in screen in the preview mode where CAF is performed, according to an embodiment of the present invention. 
     A controller  110  controls the overall operation of the mobile terminal According to an exemplary embodiment of the present invention, when a ‘capture’ entry is selected by a user while performing CAF in the preview mode, the controller  110  measures a change in motion of the captured frame by comparing the captured frame with a previous frame that has undergone AF. If the change in motion of the captured frame is greater than a threshold, the controller  110  determines that the captured frame has not undergone AF, and so performs AF on the captured frame and then stores it. However, if the change in motion of the captured frame is less than or equal to the threshold, the controller  110  determines that the captured frame has undergone AF and stores the captured frame. 
     When a ‘capture’ entry is selected by the user while performing CAF in the preview mode, the controller  110  measures a change in motion of the captured frame by comparing the captured frame with a previous frame that has undergone AF. If the change in motion of the captured frame is greater than a threshold, the controller  110  displays a message indicating that the captured frame is a frame that has not undergone AF, determines that the captured frame has not undergone AF, and automatically switches to the preview mode where CAF is performed, if a ‘store’ entry is not selected by the user within a predetermined time. If the change in motion of the captured frame is less than or equal to the threshold, the controller  110  determines that the captured frame has undergone AF and stores the captured frame. 
     In addition, when a ‘capture’ entry is selected by the user while performing CAF in the preview mode, the controller  110  measures a change in motion of the captured frame by comparing the captured frame with a previous frame that has undergone AF. If the change in motion of the captured frame is greater than a threshold, the controller  110  determines that the captured frame has not undergone AF, displays a message indicating that the captured frame is a frame that has not undergone AF, and displays the captured frame before storage thereof, if a ‘frame view’ entry is selected by the user. If a ‘store’ entry is selected by the user while displaying the captured frame, the controller  110  stores the captured frame that has not undergone AF, and if a ‘preview mode’ entry is selected by the user while displaying the captured frame, the controller  110  automatically switches to the preview mode where CAF is performed. However, if the change in motion of the captured frame is less than or equal to the threshold, the controller  110  determines that the captured frame has undergone AF and stores the captured frame. 
     When a ‘capture’ entry is selected by the user while performing CAF in the preview mode, the controller  110  measures a change in motion of the captured frame by comparing the captured frame with a previous frame that has undergone AF. If the change in motion of the captured frame is greater than a threshold, the controller  110  displays a message indicating that the captured frame is a frame that has not undergone AF, and then stores the frame that has not undergone AF, determining that the captured frame has not undergone AF. Thereafter, the controller  110  switches to the preview mode where CAF is performed, and displays a message indicating that the previously captured frame has not undergone AF, in the preview mode. In the preview mode where CAF is performed, when displaying the previously captured frame in a thumbnail image, the controller  110  displays the thumbnail image differently depending on whether the frame has undergone AF. 
     A camera module  140  includes a camera sensor for capturing image data and converting a captured optical image signal into an electrical image signal, and a signal processor for converting an analog image signal captured by the camera sensor into digital image data. The camera sensor may be a Charge Coupled Device (CCD) sensor or a Complementary Metal-Oxide Semiconductor (CMOS) sensor, and the signal processor may be realized by a Digital Signal Processor (DSP). The camera sensor and the signal processor may be realized integrally or separately. 
     An image processor  150  performs Image Signal Processing (ISP) to display the image signals output from the camera module  140  on a display  160 . The ISP performs functions such as gamma correction, interpolation, spatial conversion, image effecting, image scaling, Auto White Balance (AWB), Auto Exposure (AE), and AF. The image processor  150  processes the image signals output from the camera module  140  on a frame-by-frame basis, and outputs the frame image data according to the characteristics and size of the display  160 . The image processor  150 , including a video codec, compresses frame image data displayed on the display  160  using a predetermined coding scheme, and restores or decompresses the compressed frame image data into the original frame image data. The video codec may be a Joint Photographic Experts Group (JPEG) codec, a Moving Picture Experts Group 4 (MPEG4) codec, a Wavelet codec, etc. The image processor  150  is assumed to have an On-Screen Display (OSD) feature, and may output OSD data depending on the size of the displayed screen, under control of the controller  110 . 
     On its screen, the display  160  displays image signals output from the image processor  150 , and displays user data output from the controller  110 . The display  160  may be a Liquid Crystal Display (LCD). In this case, the display  160  may include an LCD controller, a graphic memory for storing image data, and an LCD panel. When supporting the touch screen feature, the LCD may serve as an input unit. In this case, keys like those on the key input unit  127  may be displayed on the display  160 . 
     An operation of fine-tuning and capturing images depending on the user&#39;s entry in this mobile terminal is described below with reference to  FIGS. 2 to 5 . 
       FIG. 2  shows a process of capturing images in a mobile terminal according to a first exemplary embodiment of the present invention. The first embodiment of the present invention will be described with reference to  FIGS. 1 and 2  together. 
     Referring to  FIG. 2 , while performing CAF in a preview mode in step  201 , the controller  110  stores a frame that has undergone AF, each time the screen is switched. 
     If a ‘capture’ entry is selected by a user in step  202  while performing CAF in the preview mode, the controller  110  measures a change in motion of the captured frame in step  203 . In step  203 , the controller  110  measures the change in motion of the captured frame by comparing a frame that underwent AF before the selection of the ‘capture’ entry, with the frame for which the ‘capture’ entry was selected. 
     If the change in motion of the captured frame is less than or equal to a threshold in step  204 , the controller  110  determines that the captured frame is a frame that has undergone AF and stores the captured frame in step  205 . 
     If the change in motion of the captured frame is greater than the threshold in step  204 , the controller  110  determines that the captured frame is a frame that has not undergone AF and performs AF on the captured frame in step  206 . In step  207 , the controller  110  stores the frame that has undergone AF in step  206 . 
       FIG. 3  shows a process of capturing images in a mobile terminal according to a second exemplary embodiment of the present invention. The second embodiment of the present invention will be described in detail with reference to  FIGS. 1 and 3  together. 
     Referring to  FIG. 3 , while performing CAF in a preview mode in step  301 , the controller  110  stores a frame that has undergone AF, each time the screen is switched. 
     If a ‘capture’ entry is selected by a user in step  302  while performing CAF in the preview mode, the controller  110  measures a change in motion of the captured frame in step  303 . In step  303 , the controller  110  measures the change in motion of the captured frame by comparing a frame that underwent AF before the selection of the ‘capture’ entry, with the frame for which the ‘capture’ entry was selected. 
     If the change in motion of the captured frame is less than or equal to a threshold in step  304 , the controller  110  determines that the captured frame is a frame that has undergone AF and stores the captured frame in step  305 . 
     If the change in motion of the captured frame is greater than the threshold in step  304 , the controller  110  determines that the captured frame is a frame that has not undergone AF and displays in step  306  a message indicating that the captured frame is a frame that has not undergone AF. If a ‘store’ entry is not selected by the user within a predetermined time in step  307  while displaying the message, the controller  110  automatically switches to the preview mode of step  301  where CAF is performed. If the ‘store’ entry is selected by the user within the predetermined time in step  307  while displaying the message, the controller  110  stores in step  308  the captured frame that has not undergone AF. 
       FIG. 4  shows a process of capturing images in a mobile terminal according to a third exemplary embodiment of the present invention. The third embodiment of the present invention will be described with reference to  FIGS. 1 and 4  together. 
     Referring to  FIG. 4 , while performing CAF in a preview mode in step  401 , the controller  110  stores a frame that has undergone AF, each time the screen is switched. 
     If a ‘capture’ entry is selected by a user in step  402  while performing CAF in the preview mode, the controller  110  measures a change in motion of the captured frame in step  403 . In step  403 , the controller  110  measures the change in motion of the captured frame by comparing a frame that underwent AF before the selection of the ‘capture’ entry, with the frame for which the ‘capture’ entry was selected. 
     If the change in motion of the captured frame is less than or equal to a threshold in step  404 , the controller  110  determines that the captured frame is a frame that has undergone AF and stores the captured frame in step  405 . 
     If the change in motion of the captured frame is greater than the threshold in step  404 , the controller  110  determines that the captured frame is a frame that has not undergone AF and displays in step  406  a message indicating that the captured frame is a frame that has not undergone AF. If a ‘frame view’ entry is selected by the user in step  407  while displaying the message, the controller  110  displays in step  408  the captured frame that has not undergone AF. If a ‘preview mode’ entry or a ‘cancel’ entry is selected by the user in step  409  while displaying the captured frame, the controller  110  automatically switches to the preview mode of step  401  where the CAF is performed. 
     If a ‘store’ entry is selected by the user in step  410  while displaying the message in step  406  or while displaying in step  408  the captured frame that has not undergone AF, the controller  110  stores the captured frame that has not undergone AF, in step  411 . 
       FIG. 5  shows a process of capturing images in a mobile terminal according to a fourth exemplary embodiment of the present invention. The fourth embodiment of the present invention will be described with reference to  FIGS. 1 and 5  together. 
     Referring to  FIG. 5 , while performing CAF in a preview mode in step  501 , the controller  110  stores a frame that has undergone AF, each time the screen is switched. 
     If a ‘capture’ entry is selected by a user in step  502  while performing CAF in the preview mode, the controller  110  measures a change in motion of the captured frame in step  503 . In step  503 , the controller  110  measures the change in motion of the captured frame by comparing a frame that underwent AF before the selection of the ‘capture’ entry, with the frame for which the ‘capture’ entry was selected. 
     If the change in motion of the captured frame is less than or equal to a threshold in step  504 , the controller  110  determines that the captured frame is a frame that has undergone AF and stores the captured frame in step  505 . 
     If the change in motion of the captured frame is greater than the threshold in step  504 , the controller  110  determines that the captured frame is a frame that has not undergone AF and displays in step  506  a message indicating that the captured frame is a frame that has not undergone AF. 
     While displaying the message or after displaying the message for a predetermined time, the controller  110  stores in step  507  the captured frame that has not undergone AF. 
     After storing the captured frame that has not undergone AF, the controller  110  performs CAF in the preview mode in step  508 . In step  508 , the controller  110  displays in a specific area of the display  160  a message indicating that the frame, which was previously captured and stored, has not undergone AF in the preview mode where CAF is performed. 
     For example, in the preview mode, since the previously captured and stored frame may be displayed in a thumbnail image in a specific area of the display  160 , the controller  110  may display the frame having undergone AF and the frame not having undergone AF separately when displaying the frames in the thumbnail image. The controller  110  may indicate that the previously captured and stored frame is a frame that has not undergone AF, by displaying the edge line of its thumbnail image with a different color. 
     As is apparent form the foregoing description, the proposed apparatus and method for capturing and fine-tuning images in a mobile terminal may capture images that have undergone AF, in any circumstances in the preview mode where CAF is performed. 
     While the invention has been shown and described with reference to certain exemplary embodiments thereof, 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 invention as defined by the appended claims and their equivalents.