Abstract:
There is provided a camera module including dual image sensors used for different purposes, which corrects optical defects of images imaged by the dual image sensors individually to suit purposes and processes the imaged images into image signals. The camera module includes: a plurality of image sensors imaging images with different optical properties from one another; a plurality of auxiliary image processors electrically connected to the plurality of image sensors, individually, the auxiliary image processors correcting different optical defects of the images from corresponding ones of the image sensors, respectively; and an image signal processing part selecting at least one of corrected images from the auxiliary image processors to process into an image signal capable of being displayed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority of Korean Patent Application No. 2007-44253 filed on May 7, 2007, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a camera module, and more particularly, to a camera module including dual image sensors used for different purposes from each other, which corrects optical defects of images imaged by the dual image sensors individually to suit purposes and processes the imaged images into image signals. 
         [0004]    2. Description of the Related Art 
         [0005]    Recently, mobile telecommunication service providers have implemented a high speed downlink packet access (HSDPA) nationwide. The HSDPA enables visual communication in which a person can talk visually with the other person using a mobile communication terminal such as a mobile phone and a personal digital assistant (PDA). In general, the mobile communication terminal includes an image sensor for imaging and particularly, an additional image sensor for visual communication to enable the visual communication. Hereinafter, a conventional camera module installed in the mobile communication terminal will be described with reference to  FIG. 1 . 
         [0006]      FIG. 1  is a configuration view illustrating a conventional camera module. 
         [0007]    Referring to  FIG. 1 , the conventional camera module includes a plurality of image sensors  11  and  12  and a plurality of image sensor processors (ISP)  21  and  22 . 
         [0008]    The plurality of image sensors include a first image sensor  11  imaging an image or storing the imaged image for general imaging use and a second image sensor  12  performing the visual communication as described above. 
         [0009]    In the same manner as the plurality of image sensors, the plurality of image sensor processors include a first image processor  21  processing an electrical signal from the first image sensor  11  into an image signal and a second image processor  21  processing an electrical signal from the second image sensor  12  into an image signal. 
         [0010]    As described above, the conventional camera module includes the first and second sensors  11  and  12  used for different purposes and the first and second image processors  21  and  22  processing the electrical signals from the first and second image sensors  11  and  12  into the respective image signals. 
         [0011]    This conventional camera module, when installed on a board inside a mobile telecommunication terminal, occupies a significant area of inner space, thereby increasing bulk of the mobile telecommunication terminal. 
       SUMMARY OF THE INVENTION 
       [0012]    An aspect of the present invention provides a camera module including dual image sensors used for different purposes from each other, which corrects optical defects of images imaged by the dual image sensors individually to suit purposes and processes the imaged images into image signals. 
         [0013]    According to an aspect of the present invention, there is provided a camera module including: a plurality of image sensors imaging images with different optical properties from one another; a plurality of auxiliary image processors electrically connected to the plurality of image sensors, individually, the auxiliary image processors correcting different optical defects of the images from corresponding ones of the image sensors, respectively; and an image signal processing part selecting at least one of corrected images from the auxiliary image processors to process into an image signal capable of being displayed. 
         [0014]    The image signal processing part may include: a selector selecting the corrected image from the auxiliary image processors in response to a control signal; and a main image processor processing the corrected image from the selector into the image signal. 
         [0015]    The camera module may further include a plurality of lenses optically connected to the plurality of image sensors, individually, the plurality of lenses receiving the images with different optical properties from one another. 
         [0016]    The camera module may further include a plurality of color filters optically connected to the plurality of lenses, individually, the color filters filtering the images from the lenses with a preset color to transfer to corresponding ones of the image sensors, respectively. 
         [0017]    The plurality of lenses may include: an imaging lens imaging and storing a corresponding one of the images and a visual communication lens imaging the other corresponding image for communication, the plurality of image sensors may include: an image sensor for imaging optically connected to the imaging lens and an image sensor for visual communication optically connected to the visual communication lens, and the plurality of auxiliary image processors may include: an auxiliary image processor for imaging correcting an optical defect of a corresponding one of the images from the image sensor for imaging and an auxiliary image processor for visual communication correcting an optical defect of the other corresponding image from the image sensor for visual communication. 
         [0018]    The plurality of auxiliary image processors may correct color shade of the images in the optical defects of the images. 
         [0019]    The plurality of auxiliary image processors may correct dead pixels of the images in the optical defects of the images. 
         [0020]    The image sensor for imaging and the auxiliary image processor for imaging may be formed of a first integrated circuit and the image sensor for visual communication, and the auxiliary image processor for visual communication may be formed of a second integrated circuit. 
         [0021]    The camera module may further include: a board having one surface and another surface opposing the one surface, wherein the first integrated circuit is disposed on the one surface of the board and the second integrated circuit is disposed on the another surface of the board, and each of the selector and the main image processor is disposed on one of the one surface and the another surface of the board. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0023]      FIG. 1  is a configuration view illustrating a conventional camera module; 
           [0024]      FIG. 2  is a configuration view illustrating a camera module according to an exemplary embodiment of the invention; and 
           [0025]      FIG. 3  illustrates a camera module according to an exemplary embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0026]    Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 
         [0027]      FIG. 2  is a configuration view illustrating a camera module according to an exemplary embodiment of the invention. 
         [0028]    Referring to  FIG. 2 , the camera module of the present embodiment includes an image sensor part  100 , an auxiliary image processing part  200 , and an image signal processing part  300 . 
         [0029]    The image sensor part  100  includes a plurality of image sensor units  110  and  120 . The image sensor units  110  and  120  include a lens group having a plurality of lenses  111  and  121 , and a plurality of image sensors  113  and  123  corresponding to the plurality of lenses, respectively. 
         [0030]    The plurality of lenses  111  and  121  of the lens group have optical properties different from each other and can image different images. 
         [0031]    The images received from the plurality of lenses are transferred, respectively, to the plurality of image sensors  113  and  123  corresponding to the lenses. The image sensors  113  and  123  have optical properties different form each other. 
         [0032]    A plurality of color filters  112  and  122  are disposed between the lenses and the image sensors to correspond to the lenses and the image sensors, respectively. The plurality of color filters  112  and  122  filter the images transferred from the corresponding lenses to the image sensors, respectively, with a preset color. 
         [0033]    The image sensor part  100  can perform imaging function and visual communication function as well. For the imaging function, the image sensor part  100  images an image or stores the imaged image by virtue of a high speed downlink packet access (HSDPA) implemented by a mobile telecommunication service provider. Also, for the visual communication function, the image sensor part  100  images an image to be used for communication purpose. 
         [0034]    That is, the plurality of lenses may include an imaging lens  111  receiving an image for imaging and a visual communication lens  112  receiving an image for visual communication. 
         [0035]    As described above, the imaging lens  111  and the visual communication lens  112  are different from each other in terms of angle of view and curvature, thereby allowing the received images to be different in color information such as color or color tone. 
         [0036]    Likewise, the plurality of image sensors may include the image sensor for imaging receiving the image from the imaging lens  111  and the image sensor for visual communication  122  receiving the image from the visual communication lens  121 . 
         [0037]    As described above, the image sensor for imaging  113  and the image sensor for visual communication  123  are different from each other in optical properties. For example, the image sensor for imaging  113  may have 2 million pixels and the image sensor for visual communication  123  may be formed of a common intermediate format (CIF) type, a quarter common intermediate format (QCIF) type, and a video graphics array (VGA) having 2,5000 pixels. 
         [0038]    Accordingly, electrical signals Se 1  and Se 2  transferred from the image sensor for imaging  112  and the image sensor for visual communication  122  to the auxiliary image processing part contain information about the imaged image for imaging and information about the imaged image for visual communication, respectively. 
         [0039]    The imaging lens  111  and the visual communication lens  121  may have optical defects in imaging the image. Also, the image sensor for imaging  113  and the image sensor for visual communication  123  may have optical defects. 
         [0040]    That is, the imaging lens  111  and the visual communication lens  121  may mainly undergo color-related defects and the image sensor for imaging  113  and the image sensor for visual communication  123  may entail physically dysfunctional pixels as defects. 
         [0041]    In consequence, each of the image information of the electrical signals Se 1  and Se 2  transferred from the image sensor for imaging  113  and the image sensor for visual communication  123 , respectively may contain color information and pixel information having different optical defects between the two image information. Thus the camera module of the present embodiment inevitably includes auxiliary image processors correcting the optical defects different from each other, respectively. 
         [0042]    The auxiliary image processing part  200  includes a plurality of auxiliary image processors  210  and  220 . Also, the plurality of auxiliary image processors may include an auxiliary image processor for imaging  210  and an auxiliary image processor for visual communication  220 . 
         [0043]    The first electrical signal Se 1  is transferred from the image sensor  113  for imaging to the auxiliary image processor for imaging  210 , and the second electrical signal Se 2  is transferred from the image sensor for visual communication  123  to the auxiliary image processor for visual communication  220 . 
         [0044]    As described above, the first electrical signal Se 1  contains image information about the imaged image for imaging, color information about the imaging lens  111  and pixel information about the image sensor for imaging  113 . Also, the electrical signal Se 2  contains image information about the imaged image for visual communication, color information about the visual communication lens  121  and pixel information about the image sensor for visual communication  123 . 
         [0045]    Here, the auxiliary image processor for imaging  210  corrects optical defects resulting from the imaging lens  111  and the image sensor for imaging  113  out of the information contained in the first electrical signal Se 1 . That is, the auxiliary image processor for imaging  210  corrects color shade contained in the color information of the imaging lens  111  and corrects dead pixels contained in the pixel information of the image sensor for imaging  113 . 
         [0046]    In the similar manner, the auxiliary image processor for visual communication  220  corrects color information of the visual communication lens  121  and pixel information of the image sensor for visual communication  123  out of the information contained in the second electrical signal. That is, the auxiliary image processor for imaging  210  corrects color shade contained in the color information of the visual communication lens  121  and corrects dead pixels contained in the pixel information of the image sensor for visual communication  123 . 
         [0047]    The auxiliary image processor for imaging  210  transfers a first image signal Si 1  containing corrected color information, and corrected pixel information and image information of the image for imaging to an image signal processing part  300 . Likewise, the auxiliary image processor for visual communication  210  transfers corrected color information, and corrected pixel information and image information of the image for visual communication to the image signal processing part  300 . 
         [0048]    The image signal processing part  300  receives the first and second image signals Si 1  and Si 2  from the auxiliary image processor for imaging  210  and the auxiliary image processor for visual communication  220 , respectively and processes the image signals into signals capable of being displayed. That is, the image signal processing part  300  processes the corrected color information, and corrected pixel information and image information into signals. In this case, the image signal processing part  300  performs various functions such as color interpolation, color correction, gamma conversion, auto exposure, auto focus and auto white balance. Specifically, the image signal processing part  300  produces original color for the imaged images using surrounding color through color interpolation function, corrects color difference of the imaged images through the color correction function, converts non-linear characteristics of the color of the imaged images into linear characteristics through the gamma conversion function, adjusts light amount of the imaged images through the auto exposure function, adjusts a focal point of the imaged images through the auto focus function and corrects difference in color temperature of the imaged images through the auto white balance function. 
         [0049]    The image signal processing part  300  selects one of the first image signal Si 1  and the second image signal Si 2  transferred from the auxiliary image processor for imaging  210  and the auxiliary image processor for visual communication  220 , respectively and processes the corrected color information, and corrected pixel information and image information contained in the selected image signal. 
         [0050]    Accordingly, the image signal processing part  300  may include a selector  310  selecting one of the first and second image signals Si 1  and Si 2  from the auxiliary image processing part  200  in response to a control signal Sc. Also, the image signal processing part  300  may include a main signal processor  320  receiving the image signal from the selector  310  and performing the aforesaid signal-processing function of the image signal processing part  300 . The control signal Sc can be transferred to the selector  310  by selecting the imaging function or the visual communication function through a key pad of a mobile telecommunication terminal where the camera module of the present embodiment is installed. 
         [0051]      FIG. 3  illustrates a camera module according to an exemplary embodiment of the invention. 
         [0052]    Referring to  FIG. 3 , the camera module of the present embodiment can be installed inside a mobile telecommunication terminal. The mobile telecommunication terminal having the camera module of the present embodiment installed thereon is illustrated in a lower part of  FIG. 3 . An image sensor for visual communication may be disposed in an upper part of a front of the mobile telecommunication terminal where a liquid crystal display (LCD) window is formed in order to allow a person to image his/her face to transmit to the other person. The image sensor for imaging may be located in an upper part of a rear side of the mobile telecommunication terminal. 
         [0053]    The mobile telecommunication terminal where the camera module of the present embodiment is installed is illustrated in an upper part of  FIG. 3  by an expanded perspective view. Referring to the drawing shown in the upper part of  FIG. 3 , the camera module of the present embodiment may be formed on a board B. The board B has one surface and another surface opposing the one surface. An image sensor for imaging unit  110  and an auxiliary image processor for imaging  210  may be disposed on the one surface and an image sensor for visual communication unit  120  and an auxiliary image processor for visual communication  220  may be disposed on the another surface. 
         [0054]    The image sensor for imaging unit  110  and the auxiliary image processor for imaging  210  may be formed of one chip integrated circuit (IC). Likewise, the image sensor for visual communication unit  120  and the auxiliary image processor for visual communication  210  may be formed of another chip IC. In addition, each of a selector  310  and an image processor  320  may be disposed on one of the one surface and the another surface of the board B. 
         [0055]    As set forth above, according to exemplary embodiments of the invention, a camera module includes an auxiliary image processor processing respective color information and pixel information of a plurality of lenses having optical properties different form one another, individually and a plurality of image sensors having pixel properties different from one another. This leads to reduction in size of a module. Moreover, in a case where the lenses and the image sensors are changed in characteristics, only replacement of the auxiliary image processor allows the camera module to perform its own function, thereby ensuring the camera module to be produced and repaired easily. 
         [0056]    While the present invention has been shown and described in connection with the exemplary embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.