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Comparison of sound fields generated by different coded excitations--experimental results.
A Nowicki1, Z Klimonda, M Lewandowski
1Institute of Fundamental Technological Research, Polish Academy of Sciences, Swietokrzyska 21, 00-049 Warsaw, Poland. anowicki@ippt.gov.pl
Ultrasonics
|November 30, 2005
Summary
This study investigated different ultrasound energizing schemes, finding that coded excitation significantly alters spatial pressure fields and directivity patterns compared to traditional methods. These findings are crucial for optimizing ultrasound imaging systems and transducer design.
Area of Science:
- Ultrasound physics
- Acoustic field analysis
- Biomedical engineering
Background:
- Coded excitation in ultrasound offers potential for improved signal-to-noise ratio (SNR).
- Understanding spatial field distributions is key to optimizing ultrasound imaging.
- Previous research has not fully explored the impact of various coded sequences on spatial ultrasound fields.
Purpose of the Study:
- To measure and compare the spatial distributions of ultrasound fields generated by different energizing schemes.
- To analyze the effects of Barker and Golay codes on ultrasound pressure amplitude, directivity, and focal location.
- To evaluate the differences between compressed and non-compressed ultrasound fields.
Main Methods:
- Utilized five energizing schemes: chirp, two sinusoidal sequences (Barker and Golay codes), and two sine tone bursts.
- Employed a 2 MHz, 50% fractional bandwidth, 15 mm planar transducer for measurements.
- Collected data using a computerized scanning system and a PVDF hydrophone, followed by echo compression.
Main Results:
- Coded excitation (Barker, Golay) resulted in distinct pressure amplitude levels and directivity patterns compared to continuous waves.
- Compressed fields showed directivity patterns resembling brief, wideband pulses, unlike non-compressed fields.
- Maximum pressure amplitude shifted towards the source by 15 mm (Barker) and 25 mm (Golay) after compression.
Conclusions:
- Coded excitation significantly modifies ultrasound spatial field characteristics.
- The findings support the development of novel coded excitation schemes for ultrasound.
- Optimizing transducer design for coded excitation can enhance ultrasound imaging quality.