Method for automatically determining document position in a scanner window

Abstract

A method for determining the position of a document placed in the scanning widow of a flatbed scanner is disclosed. The method can correctly determine the precise position of a document from a pre-scanned image, including portions of a pressing cover (background color), illuminator (different color from the background) and the document. By color identification, a preliminary range having a rectangular area covering the document and the illuminator is first determined. Then, the colors of the four corners of the preliminary range are identified. Finally, the precise position of the document is determined by color identification, approaching from the rim of the preliminary range toward the the document.

1 .- 6 . (canceled)  
   
   
       7 . An apparatus, comprising: 
 means for obtaining a pre-scanned image, wherein the pre-scanned image includes a document image portion and a background image portion;    means for determining a preliminary range of the pre-scanned image;    means for distinguishing at least a portion of said document image portion from said background image portion; and    means for determining a position of the document image portion within the range of the pre-scanned image.    
   
   
       8 . The apparatus of  claim 7 , wherein said means for determining said preliminary range further comprises means for locating one side of said pre-scanned image, and means for searching along the one side to identify at least one corner of the pre-scanned image.  
   
   
       9 . The apparatus of  claim 7 , wherein said means for distinguishing comprises means for identifying color differences between said document image portion and said background image portion.  
   
   
       10 . The apparatus of  claim 7 , wherein means for distinguishing comprises means for identifying one or more corners of the document image portion within the pre-scanned image.  
   
   
       11 . The apparatus of  claim 10 , wherein means for identifying one or more corners comprises means for identifying color differences between said document image portion and said background image portion at the one or more corners.  
   
   
       12 . The apparatus of  claim 10 , wherein means for identifying one or more corners further comprises means for identifying a center point of said document image portion.  
   
   
       13 . The apparatus of  claim 7 , wherein the document image portion and a background image portion comprise different colors.  
   
   
       14 . The apparatus of  claim 7 , and further comprising means for distinguishing at least a portion of said document image portion and/or said background image portion from an illuminated portion of the pre-scanned image.  
   
   
       15 . The apparatus of  claim 7 , and further comprising means for determining the positional relationship between said document image portion and said background image portion within the range of the pre-scanned image.  
   
   
       16 . An apparatus, comprising: 
 circuitry to obtain a pre-scanned image of at least a portion of a scanning object including a document portion and a background portion;    circuitry to determine a preliminary range of the pre-scanned image;    circuitry to distinguish at least a portion of the pre-scanned image comprising said portion of the document from at least a portion of the image comprising said portion of the background; and    circuitry to determine a position of the document portion within the preliminary range of the pre-scanned image.    
   
   
       17 . The apparatus of  claim 16 , and further comprising an illuminator adapted to illuminate the scanning object.  
   
   
       18 . The apparatus of  claim 16 , wherein said circuitry to determine a preliminary range further comprises circuitry to locate one side of said pre-scanned image, and searchalong the one side to identify at least one corner of the pre-scanned image.  
   
   
       19 . The apparatus of  claim 16 , further comprising circuitry to identify at least one color difference between said document portion and said background portion.  
   
   
       20 . The apparatus of  claim 16 , further comprising circuitry to identify a center point of said document portion.  
   
   
       21 . The apparatus of  claim 16 , wherein the document portion and a background portion comprise different colors.  
   
   
       22 . The apparatus of  claim 16 , further comprising circuitry to determine a positional relationship between said document portion and said background portion within the preliminary range of the pre-scanned image.  
   
   
       23 . An article comprising a computer readable storage medium having stored thereon instructions that, when executed, result in: 
 obtaining a pre-scanned image, wherein the pre-scanned image includes a document image portion and a background image portion;    determining a preliminary range of the pre-scanned image;    distinguishing at least a portion of said document image portion from said background image portion; and    determining a position of the document image portion within the range of the pre-scanned image.    
   
   
       24 . The article of  claim 23 , wherein the instructions, when executed, further result in determining said preliminary range by locating one side of said pre-scanned image, and searching along the one side to identify at least one corner of the pre-scanned image.  
   
   
       25 . The article of  claim 23 , wherein the instructions, when executed, further result in distinguishing by identifying color differences between said document image portion and said background image portion.  
   
   
       26 . The article of  claim 23 , wherein the instructions, when executed, further result in distinguishing by identifying one or more corners of the document image portion within the pre-scanned image.  
   
   
       27 . The article of  claim 26 , wherein the instructions, when executed, further result in identifying color differences between said document image portion and said background image portion at the one or more corners.  
   
   
       28 . The article of  claim 26 , wherein the instructions, when executed, further result in identifying one or more corners by identifying a center point of said document image portion.  
   
   
       29 . The apparatus of  claim 23 , wherein the document image portion and a background image portion comprise different colors.  
   
   
       30 . The article of  claim 23 , wherein the instructions, when executed, further result in determining the positional relationship between said document image portion and said background image portion within the range of the pre-scanned image.