Image segmentation system

• US 5,767,978 A
• Filed: 01/21/1997
• Issued: 06/16/1998
• Est. Priority Date: 01/21/1997
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Fan, Zhigang, Revankar, Shriram V.
• Primary Examiner(s): FRAHM, ERIC S
• Application Number:
  US08/792,950
• Time in Patent Office: 511 Days
• Field of Search: 358/296, 358/298, 358/448, 358/453, 358/456, 358/462, 358/465-467, 358/530, 358/534, 358/538, 382/173, 382/176, 382/180, 382/181, 382/199, 382/224, 382/302-304, 382/308, 382/309, 395/101, 395/109, 395/111, 395/112, 395/117, 395/118
• US Class Current: 358/296
• CPC Class Codes: H04N 1/40 Picture signal circuits H04N1/387 takes precedence
• CPC Class Codes: H04N 1/40062 Discrimination between different image types, e.g. two-tone, continuous tone

Abstract

An adaptable image segmentation system for differentially rendering black and white and/or color images using a plurality of imaging techniques. An image is segmented according to classes of regions that may be rendered according to the same imaging techniques. Image regions may be rendered according to a three class system (such as traditional text, graphic and picture systems), or according to more than three image classes. In addition, only two image classes may be required to render high quality draft or final output images. The image characteristics that may be rendered differently from class to class may include halftoning, colorization and other image attributes.

Claims

1. An image rendering system for processing a stream of data in a document processing system, said stream of data including segmentable imaging data for rendering an output image, said output image capable of being differentially rendered according to a plurality of image classes, said image rendering system comprising:

a segmentor for dividing the imaging data into a plurality of image regions;

a selector for assigning said regions to each image class; and

a processor, responsive to said selector, for differentially rendering the output image according to at least one of the plurality of image classes;

said segmentor including,

a transition intensity detector for determining a set of edges of each segmented region, and

an image intensity detector for determining an image edge intensity of each image region in the set of edges of each region wherein the image edge intensity is used to assign each image region to each image class.

2. The system of claim 1, wherein the image classes include a text class image type, a graphic class image type and a pictorial class image type.

3. The system of claim 1, wherein at least one image class includes at least two image types selected from the group of:

a text image type;

a graphic image type; and

a pictorial image type.

4. The system of claim 1, wherein said transition intensity detector labels each region according to a plurality of predetermined intensity ranges for assignment with to one of the plurality of image classes.

5. The system of claim 4, wherein predetermined intensity ranges include a strong edge pixels, weak edge pixels and very weak edge pixels.

6. The system of claim 1, wherein at least one first image class is determined and wherein at least one second image class is selected by default.

7. The system of claim 6, wherein the at least one second image class selected by default is a graphical type image class.

8. The system of claim 1, wherein each image region includes a selected block size of pixels.

9. The system of claim 8, wherein the block size of pixels is predetermined.

10. The system of claim 8, wherein the block size of pixels is variable.

11. The system of claim 1, wherein a halftoning sheme is assigned to each image class.

12. The system of claim 1, wherein a colorization scheme is assigned to each image class.