Abstract:
Disclosed are a manual focusing method and system in a photographing device, wherein the manual focusing method includes checking whether manual focusing mode for manually focusing is selected. If the manual focusing mode is selected, a window is captured which is a predetermined sized partial image taken from a photographed image. The capture image is output and displayed. Since a window captured out of the photographed image is displayed, the user is able to manually focus more accurately by reviewing the higher resolution captured image.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefits under 35 U.S.C. §119(a) from Korean Patent Application No. 2005-57939, filed on Jun. 30, 2005, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates in general to a manual focusing method and system in a photographing device. More specifically, the present invention relates to a manual focusing method and system that improves focusing by capturing a window (partial image) of an image being photographed. 
     2. Description of the Related Art 
     In a photographing device for photographing a subject and storing the photographed image, focusing is an essential part of photographing to obtain a desired image of the subject. This is called focusing. The focusing can be automatically done by a photographing device. However, when the focusing is executed without involvement of the photographer (or user), a desired subject might not be accurately focused in the way the photographer wants. 
     This is why most of photographing devices support the automatic focusing mode as well as the manual focusing mode. In the manual focusing mode, the user executes a focusing operation by pressing manual focus buttons or rotating a manual focus ring mounted on the photographing device. 
     In addition, the photographing device has a display unit through which the user can see the image of a subject currently being photographed. A typically used display unit is a standard definition (SD) LCD monitor or an SD viewfinder. 
     Since the image shown on the display unit is merely for the user&#39;s convenience, the display unit typically does not need to have high resolution. Thus, the display unit usually displays an SD image converted from a high definition image being photographed. 
     However, when focusing on a subject using the manual focusing mode, the user first needs to see an image displayed on the display unit to more accurately focus on a desired subject. Therefore, it is necessary that the image shown on the display unit is sufficiently sharp to a certain extent to permit the user to manually focus properly. 
     Unfortunately, the SD image the display unit provides is distorted from a high resolution image captured by the camera due to some signal dropout during the image conversion process. 
     As a result, the user is not able to verify sharp edges in an image being photographed and therefore, has difficulty focusing accurately. 
       FIG. 1  is a schematic block diagram of a conventional photographing device. 
     As can be seen in  FIG. 1 , the conventional photographing device includes a lens  10 , a charge-coupled device (CCD)  20 , an HD camera processing unit  30 , an HD codec  40 , an HD media interface unit  50 , media  60 , a format converter  70 , and a display unit  80 . 
     The lens  10  forms the image of a subject being photographed on the CCD  20 , and executes a focusing operation by moving back and forth in small amounts between the subject and the CCD  20 . 
     The CCD  20  is a photoelectric conversion device that produces an output voltage proportional to the quantity of incident light. For instance, the CCD  20  outputs a voltage in proportion to the quantity of an incident light transmitted through the lens to the HD camera processing unit  30 . 
     The HD camera processing unit  30  performs signal processing according to an input voltage from the CCD  20 , and generates an HD signal. 
     The HD codec  40  compresses the HD signal generated in the HD camera processing unit  30  to be recordable in the media  60 . Thus, to reproduce the HD signal from the media  60 , the compressed HD signal is restored. 
     The HD media interface unit  50  converts the HD signal compressed by the HD codec  40  into a signal in the media recordable format. In case of reproducing the HD signal from the media, the HD media interface unit  50  performs the inversion. 
     The media  60  records the HD signal that is converted in the HD media interface unit  50 . 
     The format converter  70  receives the HD signal generated in the HD camera processing unit, and converts an HD image to a downsized image with a predetermined size. For instance, if the size of the HD image is 1440*1080i, the image is downsized by the format converter  70  to 720*480i. 
     As a result, the produced image has a lower resolution than the HD image. The format converter  70  outputs the downsized image to the display unit  80 . 
     The display unit  80  is formed of an SD LCD monitor  83  and/or an SD viewfinder  85 , and displays the downsized image provided from the format converter  70 . Then, the user views the downsized version of a photographed image on the display unit  80 . By viewing the displayed image, the user can see the current focusing state or perform focusing if necessary. 
     However, as mentioned above, there is a problem in performing the focusing operation through the manual focusing mode, in that the user cannot focus as accurately as possible because of the lower resolution of the downsized image shown on the display unit. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of exemplary embodiments of the present invention to provide a manual focusing method and system in a photographing device capable of displaying a sharp image on a display unit during the focusing operation through a window capture of an image being photographed. 
     To achieve the above objects and advantages, there is provided a manual focusing method in a photographing device. The method comprises checking whether manual focusing mode for manually focusing is selected. If the manual focusing mode is selected, the device captures a window which is a predetermined sized partial image taken from a photographed image, and outputs the captured image. The captured image is displayed to assist the user in the manual focus operation. 
     Preferably, the manual focusing mode selection is executed by the operation of a manual focus button or manual focus ring mounted on the photographing device. 
     The method further includes generating and outputting a downsized version of the photographed image if the manual focusing mode is not selected. 
     In an exemplary embodiment, the location of the capture image on the photographed image can be arbitrarily set. 
     In an exemplary embodiment, the displaying step is performed on a viewfinder or LCD monitor. 
     The method further includes generating and outputting a downsized version, not a captured window, of the photographed image if a predetermined amount of time has lapsed after the manual focusing mode is set. 
     The method further includes capturing a window of the photographed image and outputting the capture image if the manual focusing mode is selected again. 
     Another aspect of the present invention provides a manual focusing system in a photographing device, which includes a control unit for checking whether manual focusing mode for manually focusing is selected. A window capture unit captures a window which is a predetermined sized partial image taken from a photographed image if the manual focusing mode is selected. The captured image is outputted and displayed on a display unit. 
     Preferably, the manual focusing mode selection is executed by the operation of a manual focus button or manual focus ring mounted on the photographing device. 
     The system further preferably includes a format converter for generating and outputting a downsized version of the photographed image if the manual focusing mode is not selected. 
     In an exemplary embodiment, the location of the capture image on the photographed image can be arbitrarily set. 
     In an exemplary embodiment, the display unit is formed of a viewfinder or LCD monitor. 
     The system further preferably includes a format converter for generating and outputting a downsized version, not a captured window, of the photographed image if a predetermined amount of time has lapsed after the manual focusing mode is set. 
     In an exemplary embodiment, if the manual focusing mode is selected again, the window capture unit captures a window of the photographed image and outputs the captured image. 
     Still another aspect of the present invention provides a photographing device for photographing an image of a subject, focusing, and storing a desired image of the subject. The device includes a control unit for checking whether manual focusing mode for manually focusing is selected. A window capture unit captures a window which is a predetermined sized partial image taken from a photographed image if the manual focusing mode is selected, and outputs the captured image. A display unit displays the output captured image. 
     Preferably, the manual focusing mode selection is executed by the operation of a manual focus button or manual focus ring mounted on the photographing device. 
     The device of claim further preferably includes a format converter for generating and outputting a downsized version of the photographed image if the manual focusing mode is not selected. 
     In an exemplary embodiment, the location of the capture image on the photographed image can be arbitrarily set. 
     In an exemplary embodiment, the display unit is formed of a viewfinder or LCD monitor. 
     The device further preferably includes a format converter for generating and outputting a downsized version, not a captured window, of the photographed image if a predetermined amount of time has lapsed after the manual focusing mode is set. 
     In an exemplary embodiment, if the manual focusing mode is selected again, the window capture unit captures a window of the photographed image and outputs the captured image. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above aspects and features of exemplary embodiments of the present invention will be more apparent from the following description in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a schematic block diagram of a conventional photographing device; 
         FIG. 2  is a schematic block diagram of a photographing device to which a manual focusing method according to an exemplary embodiment of the present invention is applied; and 
         FIG. 3  is a drawing comparing an image generated by a window capture unit of an exemplary embodiment of the present invention with an image generated by a format converter. 
     
    
    
     Throughout the drawings, like reference numbers will be understood to refer to like elements, features and structures. 
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Exemplary embodiments of the present invention will now be described in detail with reference to the annexed drawings. In the following description, detailed descriptions of known functions and configurations incorporated herein have been omitted for conciseness and clarity. 
       FIG. 2  is a schematic block diagram of a photographing device to which a manual focusing method according to an exemplary embodiment of the present invention is applied. 
     Referring to  FIG. 2 , the photographing device includes a lens  110 , a CCD  120 , an HD camera processing unit  130 , an HD codec  140 , an HD media interface unit  150 , media  160 , a format converter  170 , a display unit  180 , a window capture unit  190 , and a switching unit  195 . 
     The lens  110  forms the image of a subject being photographed on the CCD  120 , and executes a focusing operation by moving back and forth between the subject and the CCD  120 . 
     The CCD  120  is a photoelectric conversion device that produces an output voltage proportional to the quantity of incident light. For instance, the CCD  120  outputs a voltage in proportion to the quantity of an incident light transmitted through the lens to the HD camera processing unit  130 . 
     The HD camera processing unit  130  performs signal processing according to an input voltage from the CCD  120 , and generates an HD signal. 
     The HD codec  140  compresses the HD signal generated in the HD camera processing unit  130  to be recordable in the media  160 . Thus, for reproducing the HD signal from the media  160 , the compressed HD signal is restored. 
     The HD media interface unit  150  converts the HD signal compressed by the HD codec  140  into a signal in the media recordable format. In the case of reproducing the HD signal from the media, the HD media interface unit  150  performs the inversion. 
     The media  160  records the HD signal that is converted in the HD media interface unit  150 . 
     The format converter  170  receives the HD signal generated in the HD camera processing unit, and converts an HD image to a downsized image with a predetermined size. As an example, if the size of the HD image is 1440*1080i, the image is downsized by the format converter  170  to 720*480i. 
     As a result, the produced image has a lower resolution than the HD image. The format converter  170  outputs the downsized image to the display unit  180 . 
     The display unit  180  is formed of an SD LCD monitor  183  and/or an SD viewfinder  185 , and displays the downsized image provided from the format converter  170 . Then, the user checks the downsized version of a photographed image on the display unit  180 . By checking the displayed image, the user can see the current focusing state or performs focusing if necessary. 
     The window capture unit  190  receives a manual focusing mode select signal from a control unit (not shown) in case the user presses a manual focus button or operates a manual focus ring mounted on the photographing device. 
     Upon receiving a signal from the control unit (not shown), the window capture unit  190  captures a window of the HD image corresponding to the HD signal from the camera processing unit  130 , and outputs it to the display unit  180 . 
     Here, the window is a predetermined sized partial image taken from the photographed image. The location of the window may be preset in the product manufacturing stage depending on the operating environment of the photographing device, or may be arbitrarily set by the user. 
     The switching unit  195  performs a switching operation, in response to the manual focusing mode select signal from the control unit (not shown), for the window capture unit  190  to be able to capture a window of the HD image corresponding to the HD signal from the HD camera processing unit  130  and output it to the display unit  180 . 
       FIG. 3  is a drawing comparing an image generated by the window capture unit of an exemplary embodiment of the present invention with an image generated by the format converter. 
     The basic principle behind the manual focusing method in the photographing device according to an exemplary embodiment of the present invention will now be explained with reference to  FIGS. 2 and 3 . First, the user turns on the photographing device and starts photographing a desired subject. 
     Photographing of a subject is typically accompanied with focusing. If the user did not select the manual focusing mode, the CCD  120  outputs to the HD camera processing unit  130  a voltage proportional to the quantity of an incident light transmitted through the lens  110 . 
     Then, the HD camera processing unit  130  performs signal processing according to the input voltage from the CCD  120  and generates an HD signal. This HD signal is transmitted to the format converter  170 . 
     The format converter converts an image corresponding to the input HD signal into a downsized image  260  of a predetermined size, and outputs the image  160  to the display unit  180 . 
     The SD LCD monitor  183  or the SD viewfinder  185  on the display unit  180  displays the downsized image  260  provided from the format converter  170 . Compared with the HD image, the downsized image  260  has lower resolution. 
     The following will now describe an exemplary embodiment of a manual focusing method in the photographing device, given that the user selected the manual focusing mode. 
     That is, when the user selected the manual focusing mode by pressing the manual focus button or operating the manual focus ring mounted on the photographing device, the control unit (not shown) inputs a manual focusing mode select signal to the window capture unit  190 . 
     The control unit (not shown) controls the operations of the window capture unit  190  and switching unit  195 , so that the image  230  generated in the window capture unit  190  can be outputted to the display unit  180 . 
     The window capture unit  190  captures an arbitrary window on the HD image  200  corresponding to the HD signal from the HD camera processing unit  130  to generate a captured image  230 . Here, the window is a predetermined sized partial image of the HD image  200 . Therefore, the captured image  230  corresponds to a predetermined sized partial image  230  of the HD image corresponding to the HD signal from the HD camera processing unit  130 . 
     For instance, if the size of the HD image  200  corresponding to the HD signal is “1440*1080i”, the size of the image generated in the window capture unit  190  can be “720*480i”. 
     Here, the size of the image generated in the window capture unit may be preset in the product manufacturing stage depending on the operating environment of the photographing device, or may be arbitrarily set by the user. 
     Although the image  230  generated in the window capture  190  might have the same size, “720*480i”, as the downsized image  260  generated in the format converter  260 , the image  230  is a captured image taken directly from the HD image  200  corresponding to the HD signal, meaning that it exhibits the same resolution as the HD image  200  when displayed on the display unit  180 . 
     Thus, the user is able to see a photographed image with high resolution on the display unit  180 , and therefore more accurate manual focusing becomes possible. 
     Meanwhile, if a predetermined amount of time has lapsed since the user selected the manual focusing mode, the control unit (not shown) recognizes that no more manual focusing operation is needed, so it stops the operation of the window capture  190 . Again, the predetermined time may be preset in the product manufacturing stage depending on the operating environment of the photographing device, or may be arbitrarily set by the user. 
     That is, if the manual focus button or the manual focus ring is not operated for the predetermined amount time after the user selected the manual focusing mode by pressing the manual focus button or rotating the manual focus ring mounted on the photographing device, the control unit (not shown) recognizes that no more manual focusing is needed. 
     In such case, the control unit (not shown) stops the operation of the window capture unit  190 , and controls the operations of the window capture unit  190  and switching unit  195 , so that the image  230  generated in the window capture unit  190  stops being outputted to the display unit  180 . 
     As such, the format converter  170  converts the HD image  200  corresponding to the HD signal from the HD camera processing unit  130  into the downsized image  260  in predetermined size, and outputs the downsized image  160  to the display unit  180 . Then, the SD LCD monitor  183  or the SD viewfinder  185  on the display unit  180  displays the downsized image  260  from the format converter  170 . 
     However, if the user operates the manual focus button or the manual focus ring later again and reselects the manual focusing mode, the control unit (not shown) resumes the operation of the window capture unit  190  and controls the operations of the window capture unit  190  and switching unit  195 , so that the image  230  generated in the window capture unit  190  can be outputted to the display unit  180 . 
     This time, however, the display unit  180  displays the captured image  230  generated in the window capture unit  190 . 
     As explained so far, according to an exemplary embodiment of the present invention, the display unit of the photographing device displays a window image captured within the photographed image. This makes it possible for the user to manually focus with increased accuracy by checking the captured image with high resolution and high sharpness. 
     While the invention has been shown and described with reference to certain 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.