Adaptive persistence processing
US5595179A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 2, 1995 |
| Grant date | Jan 21, 1997 |
| Priority date | — |
| Expiry date | May 2, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H2021/0079
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention provides a method and system for adaptive persistence processing in an ultrasound imaging system. Acoustic signals are temporally filtered using an adaptive persistence filter, having a recursive stage followed by a nonrecursive stage. A set of filtering coefficients for each stage are supplied by a look-up table in a memory, addressed or indexed in response to a plurality of input or output pixel values. The look-up table may therefore embody any selected function of its input variables. The input variables for the look-up table function are a current input pixel value X.sub.n and a previous intermediate pixel value W.sub.n-1, and the function embodied by the look-up table includes a relative first difference function for selecting a filter coefficient. A recursive filtering coefficient .alpha. is held constant over time, while a nonrecursive filtering coefficient .gamma. is adjusted dynamically in response to the current input pixel value X.sub.n and the previous intermediate pixel value W.sub.n-1. The nonrecursive stage filter has a frequency response that attenuates higher frequency components without attenuating a broad range of lower frequency components, relati…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.