The present invention concerns a system for rendering and editing color images. In particular, the present invention relates to a system in which colored regions of a color image are rendered and edited using a binarized version of the image and a hierarchical representation of blocks of color image data within the color image.
Commonly-assigned U.S. applications Ser. No. 07/873,012, now U.S. Pat. No. 5,680,479, entitled xe2x80x9cMethod and Apparatus For Character Recognitionxe2x80x9d, Ser. No. 08/171,720, now U.S. Pat. No. 5,588,072, entitled xe2x80x9cMethod and Apparatus For Selecting Text And/Or Non-Text Blocks In A Stored Documentxe2x80x9d, Ser. No. 08/338,781, entitled xe2x80x9cPage Analysis Systemxe2x80x9d, Ser. No. 08/514,250, now U.S. Pat. No. 5,774,579, entitled xe2x80x9cBlock Selection System In Which Overlapping Blocks Are. Decomposedxe2x80x9d, Ser. No. 08/514,252, now U.S. Pat. No. 5,848,186, entitled xe2x80x9cFeature Extraction Systemxe2x80x9d, Ser. No. 08/664,674, entitled xe2x80x9cSystem For Extracting Attached Textxe2x80x9d, Ser. No. 08/751,677, entitled xe2x80x9cPage Analysis Systemxe2x80x9d, Ser. No. 08/834,856, now U.S. Pat. No. 5,825,944, entitled xe2x80x9cBlock Selection Review and Editing Systemxe2x80x9d, Ser. No. 09/002,684, entitled xe2x80x9cSystem For Analyzing Table Imagesxe2x80x9d, and Ser. No. 09/161,716, entitled xe2x80x9cColor Block Selectionxe2x80x9d, are herein incorporated as if set forth in full.
Conventional color image editing systems can be used to display an image, to select an area of the displayed image and to perform some type of editing or filtering function upon the selected area. Common editing functions include color change, rotate, resize, enhance, or blur. Such functions are adequate for certain purposes, but cannot easily be used to edit foreground and background colors in color images.
In this regard, such functions do not distinguish between various types of image data which may exist within a selected area of a color image. Therefore, in the case of document images, a background color of a selected region of text cannot be easily altered without also altering the color of pixels composing the text. For example, in a case that a user selects a text area of a document image and then chooses a blue color change function, the color of each pixel in the selected area will be changed to blue, thereby obliterating any distinction between the text pixels and the background pixels.
Of course, conventional editing systems could be used to alter background colors of a selected area by individually selecting and changing the color of each background pixel surrounding text pixels in the selected area. This process is, however, extremely time-consuming.
In view of the foregoing, what is needed is a system for editing a color document image in which background and foreground colors of various regions of the document can be individually and easily edited.
The present invention addresses the foregoing problems by providing a system utilizing a binarized version of a color image and a hierarchical representation of blocks of color image data of the color image to render and to edit various colors of the image. By virtue of the foregoing, background and foreground colors of an input color document can be rendered and edited easily and individually.
Therefore, in one aspect, the present invention is a system to render a color image using a binarized image representing the color image and a hierarchical tree structure representing the color image, the hierarchical tree structure including nodes representing respective blocks of image data within the color image, the nodes containing color information for respective blocks. The system includes defining, in a memory, of a color image rendering area corresponding to a block of image data in the color image, obtaining of foreground color information from a node corresponding to the block of image data, detecting of black pixel locations in the binarized image within an area of the binarized image corresponding to the block of image data, and assigning of the foreground color to pixels at locations in the color image rendering area corresponding to the detected black pixel locations.
As a result of the foregoing aspect, foreground colors of selected color image regions can be efficiently rendered. Moreover, the foregoing aspect of the present invention can be used to easily render foreground colors which have been changed by manipulation of the hierarchical tree.
In an additional aspect, the invention includes obtaining of background color information from the node corresponding to the block of image data, and assigning of the background color to pixels at each location in the color image rendering area which does not correspond to the detected black pixel locations. According to this aspect, background colors of a selected region can be easily rendered and edited.
In yet another aspect, the present invention is a system to edit a color image using a binarized image representing the color image and a hierarchical tree structure representing the color image, the hierarchical tree structure including nodes representing respective blocks of image data within the color image, the nodes containing color information for respective blocks. The system includes selecting of a block of image data in the color image, identifying of a node of the hierarchical tree corresponding to the selected block of image data, editing of a foreground color attribute in the identified node, defining, in a memory, of a color image rendering area corresponding to the block of image data in the color image data, obtaining of the edited foreground color attribute from the node corresponding to the block of image data, detecting of black pixel locations in the binarized image within an area of the binarized image corresponding to the block of image data, and assigning of a foreground color represented by the foreground color attribute to pixels at locations in the color image rendering area corresponding to the detected black pixel locations.
This brief summary has been provided so that the nature of the invention may be understood quickly. A more complete understanding of the invention can be obtained by reference to the following detailed description of the preferred embodiments thereof in connection with the attached drawings.