Abstract:
A method and system to detect and correct shine within a digital image is disclosed. Many images would be more aesthetically pleasing if the shine, or reflectance, from was reduced. In one embodiment of the present invention, shine on the skin of a individual in a digital image is reduced to a more aesthetically pleasing level. In this embodiment, the image is first analyzed to determine the areas of skin. The skin areas are then analyzed to determine the intensity of shine on the skin and create a shine mask. The shine mask is then used to correct the shine by adjusting the shine to a more aesthetically pleasing level.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application No. 60/934,283, entitled Method and System to Detect and Correct Shine, having a priority filing date of Jun. 12, 2008. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention generally relates to digital imaging and more specifically to a method and system to detect and correct shine. 
       BACKGROUND OF THE INVENTION 
       [0003]    The photography market has exploded with the wide adoption of digital imaging in traditional cameras, mobile phones and video cameras. These digital cameras accurately capture the moment, but also capture certain unwanted detail that users would like to correct to a more desirable level. One consistent problem is the light reflecting from an object or person in a photograph, which for purposes of this patent will be referred to as “shine.” An example of shine familiar to most people is the shiny reflection of light from the forehead of someone in the picture. In many cases, the shine makes the image unusable. 
         [0004]    Conventional methods of reducing shine are generally attempted when the image is taken. For example, the photographer will vary the light to reduce shine or apply cosmetic powders to reduce the reflectance of the surface. These methods are typically effective only in staged images where the photographer has plenty of time to position the subjects and lighting in the image. 
         [0005]    Once the image has been taken, shine is typically corrected by manually “touching-up” the image using one of many conventional photo editing software solutions. In short, the operator views the image and manually defines each area that is shiny. Using brushes or fill techniques, the operator then corrects the shiny area. This manual editing technique is time consuming and often leads to blended patches that detract from the quality of the image. 
         [0006]    Conventional solutions for correcting shine in an image are generally expensive, difficult and cannot be applied to most images. Accordingly, a method and system for correcting shine to create a more appealing image is needed. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention provides a method and system to automatically detect and correct shine within an image. The present invention is described in terms of detecting and correcting shine from human skin, but the scope of this invention should not be limited to this embodiment. The teachings of this invention can be applied to other surfaces, including organic materials like trees and plants, to metals, plastics and other inorganic materials that have varying reflective properties. 
         [0008]    In one implementation of the present invention, a method for correcting shine in an image is provided. In this implementation, the image is analyzed to determine the characteristics of human skin. A shine mask that defines the areas of shine is then calculated based on the intensity of white, green, blue and red color spaces on skin. In a particular implementation, the intensity of the shine within each area of the shine mask is also determined. The shine mask is then used to correct the shine within the image. As used herein, “correct” shall mean that the shine is adjusted to a more visually appealing level. The correction can be an adjustment of the image properties (luminance, color, hue, etc.) within all or a portion of the shine mask area. In the preferred embodiment, the intensity of the shine is reduced by adjusting the color space levels within the shine mask. 
         [0009]    At least one embodiment of this invention has the advantage of automatically detecting varying levels of shine and correcting the shine within the image. This results in images that are more visually appealing. Other advantages will be readily apparent to one skilled in the art from the following figures, descriptions, and claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    For a more complete understanding of the invention and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, wherein like reference numerals represent like parts, in which: 
           [0011]      FIGS. 1A-1C  are schematic diagrams of electronic systems in accordance with particular embodiments of the present invention; 
           [0012]      FIG. 2  is a flow chart of a method for correcting shine on skin within an original image in accordance with one embodiment of the invention; and 
           [0013]      FIG. 3  is a flow chart of a method for correcting shine on skin within an original image in accordance with another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0014]    The preferred embodiment of the present invention and its advantages are best understood by referring to  FIGS. 1-3 , wherein like numerals are used for like and corresponding parts in the various drawings. 
         [0015]      FIGS. 1A-1C  illustrate certain electronic systems  10  that utilize a shine correction application  12  running on one or more processors  14  to detect and adjust the shine  16  on the skin  17  within an original image  18  and produce a corrected image  20 . In the preferred embodiment, the shine  16  is reduced without appearing unnatural and losing image detail. The shine correction application  12  may also include other image correction/management functionality, such as resize, color management, format and other such functionality without departing from the scope and spirit of the present invention. 
         [0016]      FIG. 1A  illustrates a computer electronic system  10   a . In this embodiment, the computer electronic system  10   a  includes one or more processors  14   a . A shine correction application  12   a  is loaded into the computer electronic system  10   a  and runs on the processors  14   a . The shine correction application  12   a  operates to receive an original image  18   a  from a source, such as a removable media drive, external imaging system, storage system or other such device (not shown). The shine correction application  12   a  operates to detect the reflective shine  16  on the skin  17  of subjects within the original image  18   a . The shine correction application  12   a  reduces the shine  17  and produces a corrected image  20   a . The corrected image  20   a  can then be exported, displayed or stored. 
         [0017]      FIG. 1B  illustrates a camera electronic system  10   b.  In this embodiment, the camera electronic system  10   b  includes one or more processors  14   b . A shine correction application  12   b  is loaded into the camera electronic system  10   b  and runs on the processors  14   b . In this embodiment, the shine correction application  12   b  is generally optimized to operate on processors  14   b  having comparably low processing power. The shine correction application  12   b  operates to receive an original image  18   b  directly from the camera&#39;s optical sensor (not shown) or storage device (not shown) within the camera electronic system  10   b.  The shine correction application  12   b  operates to detect shine  16  on the skin  17  of one or more subjects within the original image  18   b . The shine correction application  12   b  reduces the shine  16  on the skin  17  and produces a corrected image  20   b . The corrected image  20   b  can then be exported, displayed or stored. 
         [0018]      FIG. 1C  illustrates a scanner electronic system  10   c,  such as a flatbed scanner, copy machine, fax or other such scanning device. In this embodiment, the scanner electronic system  10   c  includes one or more processors  14   c . A shine correction application  12   c  is loaded into the scanner electronic system  10   c  and runs on the processors  14   c . The shine correction application  12   c  operates to receive an original image  18   c  directly from the scanner&#39;s optical sensor (not shown) or storage device (not shown) within the scanner electronic system  10   c.  The shine correction application  12   c  operates to detect the shine  16  on the skin  17  of one or more subjects within within the original image  18   c . The shine correction application  12   c  reduces the shine  16  on the skin  17  and produces a corrected image  20   c . The corrected image  20   c  can then be exported, displayed or stored. 
         [0019]    It will be understood that the electronic systems  10  may comprise any suitable device or system for running the shine correction application  12 . It should also be understood that the electronic systems  10  may include other components and devices without departing from the scope and spirit of the present invention. 
         [0020]      FIG. 2  is a flow chart of a shine correction application  12   d  in accordance with one embodiment of the present invention. In this embodiment, the shine correction application  12   d  comprises the steps of opening the original image ( 18 )  200 , creating a shine mask  202 , creating a powder masks  204 ; applying the masks  206  and outputting the corrected image ( 20 )  208 . 
         [0021]    In step  200 , the original image  18  is received and opened by the shine correction application  12   d . In the preferred embodiment, the original image  18  is a color digital image with a suitable resolution. As illustrated in  FIGS. 1A-1C , the original image  18  may be received from any suitable device, system or storage system. 
         [0022]    In step  201 , a skin mask is created. In one embodiment, the original image  18  is analyzed to determine the areas of the skin  17 . Skin  17  has the spectral qualities of hemoglobin and the method looks for various frequency ranges of red in a form that typically represents human skin  17  to identify which areas of the original image  18  are skin  17 . 
         [0023]    In step  202 , a shine mask is created. In one embodiment, the areas defined by the skin mask are analyzed to determine the areas of the skin  17  that show shine  16 , or reflection, from such items as camera flash, normal room lighting, sunlight and other light sources that may produce a shine or glare on the skin. For example, skin that is sweaty or oily will exhibit more of a shine effect than skin that is dry and cosmetically altered. In the preferred embodiment, a map of the skin  17  is created. A map of the shine  16  on the skin  17  is created by correlating intense areas of ‘red’, ‘green’, and ‘blue’ shine on the skin. 
         [0024]    In step  204 , a powder mask is created. In one embodiment, the powder mask is created by blurring of the color channels to reduce reflection. This produces an effect similar to applying cosmetic powder to the skin  17  to reduce shine  16 . 
         [0025]    In step  206 , the masks from steps  202  and  204  are applied to the original image  18  to produce the corrected image  20 . In the preferred embodiment, the shine mask defines the areas of the powder mask to be applied to the original image  18 . 
         [0026]    In step  208 , the corrected image  20  is output to a location selected by the user, such as a display, storage device or other system. 
         [0027]      FIG. 3  is a flow chart of a shine correction application  12   e  in accordance with another embodiment of the present invention. In this embodiment, the shine correction application  12   e  utilizes downsizing to improve processing efficiency. 
         [0028]    In step  300 , the original image  18  is opened by the shine correction application  12   e . In step  302 , a shine mask is created. In one embodiment, shine  16  is detected using frequency information in the ‘red’, ‘green’, and ‘blue’ color channels of the original image  18 , but is not limited to RGB color space. The frequency information is analyzed to search for correlated intense areas of ‘red’, ‘green’, and ‘blue’ shine  16  on the skin  17 . The detected areas become a mask for the next processing steps. In step  304 , the shine mask is downsized for processing efficiency. 
         [0029]    In step  306 , the shine areas are analyzed to determine the areas of skin  17 . Skin  17  has the spectral qualities of hemoglobin and the method looks for various frequency ranges of red in a form that typically represents human skin  17  to identify which areas of the shine mask are located on skin  17 . In step  308 , a deep red mask is created. In one embodiment, the skin mask and deep red mask utilize of a combination of median filters, Gaussian filters, and gamma correction to create the masks. 
         [0030]    In step  310 , in parallel with creating the shine mask in step  302 , the original image  18  is downsized. In step  312 , a preliminary restore mask is created using the downsized image from step  310  and the deep red mask from step  308 . In step  314 , a restore mask is calculated from the preliminary restore mask and the skin only mask calculated in step  306  using inversion, mixing, and blurring. 
         [0031]    In step  316 , a preliminary powder mask and preliminary reflection mask are calculated from the downsized original image of step  310 . These masks are calculated using inversion, mixing, and blurring. In step  318 , the preliminary powder and reflection masks are used in conjunction with the ‘restore mask’ calculated in step  314  to create the ‘powder mask’ and ‘reflection mask’. 
         [0032]    In step  320 , the reflection mask calculated in step  318  is upsized. In step  322 , the masks are applied. Specifically, the upsized reflection mask is used in conjunction with the original ‘no-shine’ image to create an RGB image in which the ‘red’ contains the final output. In addition, the green and blue channels are used in conjunction with the ‘powder mask’ image to create the final ‘green’ and ‘blue’ channels without shine. These combined channels constitute the corrected image  20 . In step  324 , the corrected image  20  is output to any suitable display, device, storage or network as stipulated by the user. 
         [0033]    Throughout the description and claims of this specification the word “comprise” and variation of that word, such as “comprises” and “comprising”, are not intended to exclude other additives, components, integers or steps. While the invention has been particularly shown and described in the foregoing detailed description, it will be understood by those skilled in the art that various other changes in form and detail may be made without departing from the spirit and scope of the invention as set forth in the appended claims.