EP0227848B1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Image preprocessing procedure for noise removal
Assignee: International Business Machines Corp
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Filing: 1985-12-17
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Granted: 1991-05-29
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Expires: 2005-12-17
Abstract
No abstract record available.
Inventors
- 👤 Friedrich Michael Dr. Wahl
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 18:40
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/409; H04N1/4097; G; G06; G06T; G06T5/00; G06T5/20
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
213 words
A method of preprocessing an image represented by a raster pattern of black and white picture elements, for removing noise in the form of small black spots, including the procedure of scanning the image to obtain for each one of successive overlapping window areas an inner window (R1) of close neighbourhood picture elements and an outer window (R2) of picture elements surrounding said inner window, each picture element being represented by a binary value, characterized by the steps of: - (A) detecting for each such inner window whether the number (CT) of black picture elements exceeds a given threshold value (TH), and leaving the contents of said inner window unchanged if the number of black picture elements is above the threshold, but if the number of black picture elements in the inner window is not above the threshold, going to step (B); - (B) detecting whether any adjacency exists for black picture elements in the inner window and black picture elements in the outer window, and if an adjacency exists, leaving the contents of the inner window unchanged, but replacing all black picture elements by white picture elements in the inner window if no adjacency relationship exists between black picture elements in the inner window and black picture elements in the outer window.
Claim 2
Dependent Claim
44 words
A method in accordance with claim 1, characterized in that the inner window has a size of n x n picture elements, and the outer window has the form of frame having a dimension of (n + 2) x (n + 2) picture elements.
Claim 3
Dependent Claim
13 words
A method in accordance with claim 2, characterized in that n = 3.
Claim 4
Dependent Claim
49 words
A method in accordance with claim 1, characterized in that for considering a picture element in the outer window to be adjacent to a picture element in the inner window, it must be in direct horizontal, vertical, or diagonal connection with the respective picture element in the inner window.
Claim 5
Dependent Claim
57 words
A method in accordance with claim 1, characterized in that the movements of the window area which correspond to the succession of the said overlapping window areas are made in increments of one picture element, and that the modifications made in the contents of one window are effective for the following windows containing the same picture elements.
References Cited (Backward Citations)
No citation records indexed.
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