Fast median filter
US5144568A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 1, 1989 |
| Grant date | Sep 1, 1992 |
| Priority date | — |
| Expiry date | Sep 1, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H17/0263
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A fast median filter is disclosed for filtering high frequency noise from signals, such as, signals from a radio altimeter. The filter continuously provides the median of a predetermined number of points of the signal, which are received in an array, by successively comparing each data point in the array with each other data point in the array. A counter is either incremented or decremented depending on the result of each comparison. If the counter reaches a predetermined value at the end of the sequence of comparisons, the median is determined. A pointer keeps track of the oldest data point in the array. After the median is determined, a new data point is received into the array and written over the oldest data point. The median of the array is determined each time the array is updated with a new data point. When the pointer reaches the last position in the array, the pointer is reset to the first position and is subsequently increment in the same manner.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.