Patent Document

FIELD OF THE INVENTION 
     The present invention relates generally to improving the image quality during digital zoom in cameras without optical zoom capability. 
     BACKGROUND OF THE INVENTION 
     Optical zooming in camera entails the translational moving of a lens to magnify the image. In less capable cameras such as those typically included in wireless telephones and personal digital assistants (PDAs), the lenses do not move. To provide for a zoom-like function, digital zooming is used in which, for example, a portion of the image is cropped and the remaining image simply enlarged to fill the image screen. As understood herein, while digital zooming simulates the magnification yielded by optical zooming, it reduces image quality compared to optical zooming. 
     SUMMARY OF THE INVENTION 
     A method includes receiving a user selection of digital zooming in a camera and in response automatically generating plural images. The images are digitally zoomed and then superimposed to produce an improved digital zoom image transparently to the user. 
     The superimposition may be undertaken using super-resolution. The camera can be incorporated into a wireless telephone or personal digital assistant (PDA) or other device that does not have optical zoom capability. If desired, prior to zooming the images a portion of each image can be removed to render respective cropped images, and the cropped images are digitally zoomed. 
     In another aspect, an apparatus includes an imager, a processor communicating with the imager to receive signals therefrom, and a computer readable medium accessible to the processor and bearing instructions. The instructions cause the processor, in response to a predetermined user command to generate at least two images automatically and digitally zoom each image to render a respective zoomed image. The instructions also cause the processor to superimpose the zoomed images on each other to render a modified zoomed image. 
     In still another aspect, an apparatus includes an imager, a display, and a processor configured to present on the display a modified digital zoom image including at least two superimposed images. 
     The details of the present invention, both as to its structure and operation, can best be understood in reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a non-limiting device that can incorporate present principles, with some components shown schematically; and 
         FIG. 2  is a flow chart of non-limiting logic in accordance with present principles. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring initially to  FIG. 1 , an apparatus is shown, generally designated  10 , that can include an imager  12  such as a charge coupled device (CCD) and a processor  14  receiving image signals from the imager  12 . The processor  14  can access a computer readable storage medium  16  such as but not limited to removable or non-removable solid state memory, disk memory, etc. The logic of  FIG. 2  may be embodied as computer instructions on the medium  16  that are executable by the processor  14  to present a digitally zoomed image on a display  18  in accordance with principles set forth below. 
     The apparatus  10  may be embodied as a wireless telephone or personal digital assistant (PDA) or other portable device with a portable housing  20  in which, in one embodiment, the display  18  may be hingedly coupled to a base  22 . The base  22  can be bear an input device  24  such as a telephone keypad, and one or more controls  26 , both of which generate input signals to the processor  14  when manipulated. Among the user commands that can be input is a “digital zoom” command. The apparatus  10  may not have optical zoom capability. A wireless telephony receiver  28  may also be incorporated in the apparatus  10 . 
     Now referring to  FIG. 2 , at block  30  a predetermined command from the user such as a digital zoom command is received. The command may be generated by, e.g., manipulating the control  26 . In response, at block  32  plural images from the imager  12  are captured automatically in quick succession, e.g., within a few seconds of receiving the command. This occurs automatically, transparently to the user. 
     In some embodiments a portion of each image is removed from the image to render a cropped image at block  34 . The cropped images are digitally zoomed at block  36  by, e.g., expanding the remaining image pixels to fill the original image area. Then, the zoomed images are combined at block  38  by superimposing them on each other to render a modified zoomed image that has higher resolution than any of the images from which it is derived. In one implementation, the superimposition may be done using super-resolution principles such as those disclosed in, e.g., U.S. Pat. Nos. 6,208,765 and 7,218,751, incorporated herein by reference. The modified zoomed image is presented on the display at block  40 . 
     As understood herein, if super-resolution techniques are used that require relative motion between successive images, this requirement may be satisfied by the inevitable hand movement that occurs when a person holds a camera, which results in a sequence of images in a few seconds each of which is slightly different than the others. If motion calculation is required, motion estimation algorithms may be employed. For example, a simple algorithm might be to estimate motion using groups of pixels in each image that remain substantially unchanged in value except for their relative positions within the images, with motion vectors being derived directly from the motion of the groups of pixels from image to image. The super-imposition techniques may use Bayesian or Kalman filtering techniques in rendering the final, modified zoomed image. 
     The super-resolution processing may be executed in near real-time by the processor  14  as described above, or the images captured at block  32  and cropped at block  34  may be stored in the medium  16  and later downloaded to a personal computer or the like for subsequent steps to be performed off-line to render a final modified high resolution image that can then be printed or displayed on a large display such as a PC screen or TV. 
     While the particular SUPER-RESOLUTION DIGITAL ZOOM is herein shown and described in detail, it is to be understood that the subject matter which is encompassed by the present invention is limited only by the claims.

Technology Category: 5