Design of quadratic filters for contrast-assisted ultrasonic imaging

Pornchai Phukpattaranont, Tojsaporn Nilmanee, Chusak Limsakul, Emad S. Ebbini

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


We present a novel design of a quadratic filter (QF) in order to improve the quality of contrast-assisted ultrasound images for medical diagnosis. The design of QFs for capturing the second order nonlinearities is performed in frequency domain. The two-dimensional (2D) frequency response of the optimum quadratic filter is composed of two 2D Gaussian functions with different spreads in their major and minor axes. The centers of the Gaussian functions are positioned at frequency pairs where the contrast-to-tissue (CTR) ratio is maximal along the main diagonal of 2D frequency plane. Subsequently, the bandwidth of filter is independently determined to optimize spatial resolution. Therefore, the new design approach offers two degrees of freedom in maximizing the CTR and spatial resolution simultaneously. This avoids the inherent tradeoff between contrast and spatial resolution when linear filters are used (e.g. in second harmonic imaging). We demonstrate the performance of the new approach with echo data from a flow phantom.

Original languageEnglish (US)
Title of host publication2007 IEEE Ultrasonics Symposium Proceedings, IUS
Number of pages4
StatePublished - 2007
Event2007 IEEE Ultrasonics Symposium, IUS - New York, NY, United States
Duration: Oct 28 2007Oct 31 2007

Publication series

NameProceedings - IEEE Ultrasonics Symposium
ISSN (Print)1051-0117


Other2007 IEEE Ultrasonics Symposium, IUS
Country/TerritoryUnited States
CityNew York, NY


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