Activity detector

• US 7,386,171 B2
• Filed: 08/27/2007
• Issued: 06/10/2008
• Est. Priority Date: 04/25/2002
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Simard, Patrice Y.
• Primary Examiner(s): Bella; Matthew C.
• Assistant Examiner(s): LIEW, ALEX KOK SOON
• Application Number:
  US11/845,588
• Publication Number:
  US 20070292028A1
• Time in Patent Office: 288 Days
• Field of Search: None
• US Class Current: 382/195
• CPC Class Codes: G06V 30/413 Classification of content, e.g. text, photographs or tables

Abstract

A system and method facilitating activity (e.g., dithering/half toning and/or noise) detection is provided. The invention includes an activity detection system having a connected component analyzer and an activity detector. The invention provides for the quantity of connected component(s) in and/or intersecting a region surrounding a pixel to be determined. The activity detector provides an activity map output based, at least in part, upon the quantity of connected component(s) in and/or intersecting the region. The invention further provides for an optional image processor. In one example, if the quantity exceeds a first threshold, dithering/half toning is detected and appropriate action can be taken. Additionally, if the quantity is less than a second threshold, noise is detected and appropriate action can be taken.

Claims

1. A segmented layered image system, comprising:

a mask separator adapted to assign pixels of a document image into at least one of a foreground and a background, the assignment information stored in a binary mask;

a connected component identifier adapted to identify connected components in or intersecting a region surrounding a pixel;

a connected component analyzer adapted to determine a quantity of connected components in or intersecting the region surrounding the pixel by maintaining an identity of substantially all the quantity of connected components and a relative quantity of each connected component in the region surrounding the pixel;

an activity detector that provides an activity map output based, at least in part, upon the quantity of connected components in or intersecting the region; and

,

an image processor that assigns the pixel to one of the background or the foreground based at least in part upon activity map output;

wherein said activity detector identifies bounding boxes of the connected components, said bounding boxes are enlarged and creates a derivate image of the enlarged bounding boxes; and

wherein the image processor assigns to the foreground based at least in part upon a determination that the quantity of connected components exceeds a first threshold, and assigns the pixel to the background based at least in part upon a determination that the quantity of connected components is less than a second threshold.

2. The segmented layered image system of claim 1, the image processor determines a quantity of pixels in the background of the region and a quantity of pixels in the foreground of the region, the activity detector assigns the pixel to the foreground if the quantity of pixels in the foreground of the region is greater than the quantity of pixels in the background of the region, the activity detector otherwise assigns the pixel to the background.

3. The segmented layered image system of claim 1, the image processor assigns the pixel to the background if the quantity of connected components is less than a third threshold.

4. The segmented layered image system of claim 1, the connected component analyzer and the image processor receives a bi-level image input comprising a plurality of pixels assigned to at least one of the foreground and the background, the image processor provides a bi-level image output, the bi-level image output being based at least in part upon the bi-level image input and assignment of at least one pixel to one of the background or the foreground based at least in part upon the activity map output.

5. The segmented layered image system of claim 1, the activity detector further identifies bounding boxes of the connected components.

6. The segmented layered image system of claim 5, the activity detector further enlarges the bounding boxes.

7. The segmented layered image system of claim 6, the activity detector further creates a derivate image of the enlarged bounding boxes.

8. The segmented layered image system of claim 7, the activity detector provides an output associated with a double integral of the derivate image.

9. The segmented layered image system of claim 6, the activity detector further creates a derivate image of a lower resolution of the enlarged bounding boxes.

10. The segmented layered image system of claim 9, the activity detector provides an output associated with a double integral of the derivate image.

11. The segmented layered image system of claim 1, the activity detector further dilates the activity map output.

12. The segmented layered image system of claim 1, the activity detector further erodes the activity map output.

13. The segmented layered image system of claim 1, the activity detector further smoothes the activity map output.