Signal adaptive filtering method for reducing ringing noise and signal adaptive filter
US6226050A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 3, 1998 |
| Grant date | May 1, 2001 |
| Priority date | — |
| Expiry date | Apr 3, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/21
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A gradient is calculated at each pixel of the image data to be filtered using a one-dimensional horizontal gradient operator of 1.times.2 size and a one-dimensional vertical gradient operator of 2.times.1 size, each of the gradient operators having a weighted value (1,-1). The absolute value of the calculated gradient is then compared with a predetermined threshold value to generate a binary value. This gradient calculation and comparison with a threshold is repeated for pixel blocks having a predetermined size to generate a binary edge map with respect to a whole block. A filter window of a predetermined size is then applied to the generated binary edge map to determine whether edges are present in the filter window. If no edges are present in the filter window, then the pixel values of the corresponding filter window pixel are filtered pixel-by-pixel by using a predetermined first set of weighted values to generate a new pixel value. On the other hand, if edges are present in the filter window, then (subject to an exception) the pixel values of the corresponding filter window are filtered pixel-by-pixel by using a predetermined second set of weighted values to generate a new pixe…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.