Invention Publication
EP0188193A2 Method and apparatus for processing image data
失效
Verfahren und Vorrichtung zur Bilddatenbearbeitung。
- Patent Title: Method and apparatus for processing image data
- Patent Title (中): Verfahren und Vorrichtung zur Bilddatenbearbeitung。
-
Application No.: EP86100035.4Application Date: 1986-01-02
-
Publication No.: EP0188193A2Publication Date: 1986-07-23
- Inventor: Pennebaker, William Boone , Mitchell, Joan La Verne
- Applicant: International Business Machines Corporation
- Applicant Address: Old Orchard Road Armonk, N.Y. 10504 US
- Assignee: International Business Machines Corporation
- Current Assignee: International Business Machines Corporation
- Current Assignee Address: Old Orchard Road Armonk, N.Y. 10504 US
- Agency: Ahlman, Bertel
- Priority: US692007 19850115
- Main IPC: H04N1/40
- IPC: H04N1/40
Abstract:
A method and apparatus for processing images using gray scale techniques includes means (40) for obtaining a histogram of levels in an image; means (42) for analyzing said histogram to identify one or more ranges of background in said image; means (44, 48, 52) for converting each of said ranges of background to a constant value to achieve flat backgrounds in said image; means for generating a dynamic range expansion table for each image; means for correcting said image data for dynamic range compression due to coring during processing of said image data by reference to said dynamic range expansion table. The process may also include means for encoding (54) said processed image using gray scale encoding techniques, means (46) for filtering all nonbackground pixels in said image, means for generating for said image a shading correction for each pixel in said image; means for correcting each pixel for shading employing said shading correction generated for each pixel, means for determining if said image is a graphics image; means for generating a dynamic range expansion table for each graphics image; means for correcting said image data for dynamic range compression by reference to said dynamic range expansion table, means for creating a second table of values from parameters contained in said encoded image data; and means for translating decoded image pixel values by reference to said second table to correct for quantization noise.
Public/Granted literature
- EP0188193A3 Method and apparatus for processing image data Public/Granted day:1989-04-19
Information query