Patent Publication Number: US-2005122414-A1

Title: Digital camera system and method for maximizing television viewing area

Description:
TECHNICAL FIELD  
      The present invention relates generally to digital cameras and methods.  
     BACKGROUND  
      Digital cameras certainly have come of age when it comes to capturing and instantly reviewing photographs. More and more however, digital cameras are often used as a sharing device for showing pictures stored in the camera with friends and family. Many times this is done using a video output port of the camera and a conventional television.  
      The television signal is generally much larger than that displayed on the television. There are large borders across the top, bottom, left and right of the television that are not displayed. The television signal is on the order of 1700 pixels wide, while only 600 pixels are displayed. Due to calibration issues, the 600 pixels can vary such that the television displays 700 or 500 pixels, for example. Thus, the number of pixels that are displayed varies. The same thing occurs with the top and bottom borders of the television.  
      Conventional solutions simply output a television signal that is “nearly” guaranteed to be larger than the viewing area, and then centers this image within the television video frame. This causes clipping to occur and loss of viewable image area.  
      It would be desirable to maximize the viewing experience when a digital camera is coupled to a television in a manner that maximizes the viewing area of the television.  
     SUMMARY OF THE INVENTION  
      The present invention provides for a digital camera system and method that automatically maximizes television viewing area when a television is used to view images stored in or transferred from a digital camera. In an embodiment of the present invention, a test signal or image comprising a beacon is output from the digital camera and is displayed on a television screen. A user points the camera at the television.  
      Firmware that runs on the digital camera moves the test signal and beacon horizontally and vertically towards respective edges of the television screen until the beacon is lost at each edge, and determines or calculates how much viewing area is available on the television screen. The autocalibration firmware then automatically adjusts the size of images sent from the digital camera to the television to maximize the viewing area on the television while minimizing cropping or clipping of the images. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The various features and advantages of embodiments of the present invention may be more readily understood with reference to the following detailed description taken in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which:  
       FIGS. 1   a  and  1   b  are rear and front views, respectively, of an exemplary digital camera that may be used in a system in accordance with the principles of the present invention;  
       FIG. 2  illustrates an exemplary system in accordance with the principles of the present invention; and  
       FIG. 3  illustrates an exemplary method in accordance with the principles of the present invention. 
    
    
     DETAILED DESCRIPTION  
      Referring to the drawing figures,  FIGS. 1   a  and  1   b  are rear and front views, respectively, of an exemplary digital camera  10  implemented in accordance with the principles of the present invention. As is shown in  FIGS. 1   a  and  1   b , the exemplary digital camera  10  comprises a handgrip section  20  and a body section  30 . The handgrip section  20  includes a power button  21  or switch  21  having a lock latch  22 , a record button  23 , a strap connection  24 , and a battery compartment  26  for housing batteries  27 . The batteries may be inserted into the battery compartment  26  through an opening adjacent a bottom surface  47  of the digital camera  10 .  
      As is shown in  FIG. 1   a , a rear surface  31  of the body section  30  comprises a liquid crystal display (LCD)  32  or viewfinder  32 , a rear microphone  33 , a joystick pad  34 , a zoom control dial  35 , a plurality of buttons  36  for setting functions of the camera  10  and a video output port  37  for downloading images to a computer, for example. As is shown in  FIG. 1   b , a zoom lens  41  extends from a front surface  42  of the digital camera  10 . A metering element  43  and front microphone  44  are disposed on the front surface  42  of the digital camera  10 . A pop-up flash unit  45  is disposed adjacent a top surface  46  of the digital camera  10 .  
      An image sensor  11  is coupled to processing circuitry  12  (illustrated using dashed lines) that are housed within the body section  30 , for example. An exemplary embodiment of the processing circuitry  12  comprises a microcontroller (μC)  12  or central processing unit (CPU)  12 . The (μC  12  or CPU  12  is coupled to a nonvolatile (NV) storage device  14 , and a high speed (volatile) storage device  15 , such as synchronous dynamic random access memory (SDRAM)  15 , for example.  
      The processing circuitry  12  (microcontroller (μC)  12  or CPU  12 ) in the digital camera  10 , embodies firmware  13  comprising an autocalibration algorithm  13  in accordance with the principles of the present invention. This will be discussed in more detail with reference to  FIGS. 2 and 3 .  
      Referring now to  FIG. 2 , it illustrates an exemplary system  50  in accordance with the principles of the present invention. The exemplary system  50  comprises a digital camera  10 , such as the digital camera  10  discussed with reference to  FIGS. 1   a  and  1   b , for example, that is coupled to a television  51 . The television  51  has a screen  52 . The digital camera  10  is coupled from its video output port  37  by way of a cable  54 , such as a coaxial cable or composite video cable, for example, to the television  51 . A video test signal  53  or image  53  comprising a beacon  56  is stored in the digital camera  10 , such as in the nonvolatile storage device  14 , for example.  
      In accordance with the present invention, the digital camera  10  includes a user interface  55  implemented using the autocalibration firmware  13  (or software algorithm  13 ) that runs on the processing circuitry  12  (microcontroller (μC)  12  or CPU  12 ). The autocalibration firmware  13  is configured to automatically maximize television viewing area on the screen  52  when viewing images stored or transferred from the digital camera  10  to the television  51 .  
      The firmware  13 , by way of the user interface  55 , prompts the user to point the digital camera  10  at the television  51 . This may be accomplished by directing the user to point the digital camera  10  substantially straight at the television to avoid potential problems relating to angular issues. The firmware  13  on the digital camera  10  outputs a test signal  53  by way of the output port  37  to the television  51 , which is displayed on the television screen  52 . The test signal  53  comprises a beacon  56  that is recognizable by the firmware  13 . Once pointed at the television  51 , the lens  41  and image sensor  11  views the test signal  53  and beacon  56  displayed on the television screen  52 . The output of the image sensor  11  is processed by the firmware  13 .  
      The firmware  13  automatically adjusts the video signal output to the television  51  until an optimal image viewing area of the displayed image has been achieved. To achieve this, the firmware  13  performs a process that slides the test signal  53  to the left of the television screen  52 , for example, and determines at which point it loses the beacon  56  in the television signal. The firmware repeats this process for the right side, the top side, and the bottom side of the television screen  52 .  
      Once these operations are completed, the firmware  13  determines or calculates how much viewing area is available on the television screen  52 , which is related to the locations at which the beacon  56  is lost relative to the four sides of the television screen  52 . The firmware  13  then adjusts the sizes of the images that are transferred from the camera  10  and displayed on the television screen  52  to provide for the maximum viewing area while minimizing cropping or clipping of the images. To accomplish this, the resolution of the transferred images are adjusted to match the resolution of the television screen  52 .  
      By way of example, the present invention may be used to adjust the viewing areas of a high definition television (HDTV) having a 16:9 display format or a standard television (NTSC) having a 4:3 display format.  
      Some CRT displays used with personal computers have buttons on the front panel that allow the user to set the size of the screen to occupy the entire visible area, for example. While this technique is used with personal computer displays, it has not heretofore been used as a feature that available with digital cameras  10 . The present invention may be used to implement this feature by providing firmware  13  that displays a menu, or buttons, for example, by way of the user interface  55  that allow the user to selectively adjust the horizontal and vertical size of the displayed image. This technique may also be used to adjust the television for HDTV and NTSC display formats.  
      For the purposes of completeness,  FIG. 3  illustrates an exemplary method  60  in accordance with the principles of the present invention. The exemplary method  60  comprises the following steps.  
      A digital camera  10  is provided 61 that comprises a lens  41 , an image sensor  11 , a display  32 , a video output port  37 , and processing circuitry  12 . A television  51  having a screen  52  is provided 62. The digital camera  10  is coupled  63  to a television  51 , such as by using the output port  37  and a cable  54 , for example. A test signal  53  comprising a beacon  56  is stored  64  in the digital camera  10 .  
      The digital camera  10  is configured  65  with autocalibration firmware  13  that runs on the processing circuitry  12 . When initiated  66 , the autocalibration firmware  13  prompts  67  the user to point the digital camera  10  at the television  51 , displays  68  the test signal  53  on the television  51 , processes  69  the test signal  53  displayed on the television  51  that is imaged the image sensor  11 .  
      The autocalibration firmware  13  moves  70  the test signal  53  and beacon  56  horizontally and vertically towards respective edges of the display screen  52  until the beacon  56  is lost at each edge, and determines  71  or calculates  71  how much viewing area is available on the television screen  52 . The autocalibration firmware  13  then automatically adjusts  72  the size of images sent from the digital camera  10  to the television  51  to maximize the viewing area on the television  51  while minimizing cropping or clipping of the images.  
      The present invention solves the problem of varying television viewing areas. By using the present invention, the digital camera  10  automatically determines where the viewable limits of the television  51  are located and then calculates the correct locations within an analog television signal that maximizes the displayed picture with minimal cropping or clipping. The present invention thus maximizes the viewing experience when using a television  51  to display images stored in a digital camera  10  in a manner that maximizes the usable area of the television  51 .  
      Thus, digital cameras and methods that automatically maximize television viewing area for images and viewed on the television have been disclosed. It is to be understood that the above-described embodiments are merely illustrative of some of the many specific embodiments that represent applications of the principles of the present invention. Clearly, numerous and other arrangements can be readily devised by those skilled in the art without departing from the scope of the invention.