Enhanced method for reducing ultrasound speckle noise using wavelet transform
US5619998A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 1996 |
| Grant date | Apr 15, 1997 |
| Priority date | — |
| Expiry date | Mar 11, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S7/52046
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Signal-dependent noise in a coherent imaging system signal, such as in medical ultrasound imaging, is reduced by filtering speckle noise using nonlinear adaptive thresholding of received echo wavelet transform coefficients, thereby enhancing the resultant image by improving the signal-to-noise ratio. The method includes the steps of dividing the imaging system signal into a number of subinterval signals of equal length; transforming each subinterval signal using discrete wavelet transformation to provide wavelet transform coefficients for each of a plurality of wavelet scales having different levels of resolution ranging from a finest wavelet scale to a coarsest wavelet scale: deleting all of the wavelet transform coefficients representing the finest wavelet scale: for each wavelet scale other than the finest wavelet scale, identifying for each subinterval signal which of the wavelet transform coefficients are related to noise and which are related to a true signal through the use of adaptive nonlinear thresholding; selecting those wavelet transform coefficients which are identified as being related to a true signal; and setting to zero those wavelet coefficients which are identifi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.