EP0502622A1
Expired / Lapsed
EP
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Image processing method
Assignee: Nortel Networks Ltd
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Filing: 1992-02-14
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Granted: —
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Expires: 2012-02-14
Abstract
Abstract A method of digitally processing images, in the form of a two dimensional data element array, in which the image is compressed by dividing the array into blocks (2) and performing transformation thereon. In order to smooth discontinuities at the boundaries (1, 13, 3, 14) between the blocks (2) resulting from the compression, filtering is performed by sequentially scanning elements at the boundaries with a one dimensional operator matrix (6, Fig, 1). The matrix applies suitable weights to those elements and adjacent ones to effect smoothing.
Inventors
- 👤 Anthony Harold Downing
- 👤 John Whitaker
- 👤 Robert George Hadingham
- 👤 Jeremy Bentley D'assis Fonseca
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 18:18
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/50; H04N19/503; H04N19/51; H04N19/527; H04N19/85; H04N19/86
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
107 words
A method of digitally processing an image in the form of a two-dimensional data array having elements arranged in rows and columns, wherein the image is compressed by dividing the array into blocks (2) and performing transformation on the blocks, and wherein the image is filtered by convolution with an operator matrix (6) substantially smaller than the array, characterised in that the filtering is used to smooth discontinuities, at boundaries (1, 13, 3, 14) between said blocks, resulting from said compression, and comprises sequentially scanning elements of the data array at the data array block boundaries (1, 13, 3, 14) with a one dimensional operator matrix (6).
Claim 2
Dependent Claim
38 words
A method as claimed in claim 1 characterised in that the one dimensional operator matrix (6) is first scanned over the block boundaries extending in one direction and then over the block boundaries extending in the orthogonal direction.
Claim 3
Dependent Claim
50 words
A method as claimed in claim 1 characterised in that the operator matrix is applied first to smooth an array element value on one side (7) of said boundary (1) and then applied to smooth the adjacent array element value on the opposite side (9) of the said boundary (1).
Claim 4
Independent Claim
24 words
A method as claimed in any one of claims 1 to 3 characterised in that the operator matrix (6) is comprised of three elements.
Claim 5
Dependent Claim
66 words
A method as claimed in claim 4 wherein the operator matrix (6) serves to apply respective weights to an array element (7) on one side of a said boundary (1), the array element (8) adjacent thereto in the same block (2) and the array element (9) adjacent thereto in the neighbouring block (2), which array elements are disposed in a line orthogonal to the said boundary.
Claim 6
Dependent Claim
16 words
A video-telephone employing an image processing method as claimed in any one of the preceding claims.
References Cited (Backward Citations)
US4754492A
Cited
US4941043A
Cited
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