Ultrasound imaging using vector quantization of RF channel data

Because the signals received by adjacent elements of an ultrasound transducer array is often highly correlated, these signals can be grouped into multi-dimensional vectors and vector quantization (VQ) can be applied to improve the quantization efficiency over conventional scalar quantization (SQ). In this research, both simulation data and experimental data are used to test this hypothesis. The signal-to-quantization noise ratio (SQNR), B-mode image quality, accuracy in phase aberration correction and accuracy in blood velocity estimation are assessed. Results show that there is about a 10dB quantization noise reduction by VQ compared to conventional SQ, particularly when bit length is short. The image degradation in B-mode is minimal. Nevertheless, velocity estimation accuracy is affected by corruption of the phase data, thus restricting the bit length reduction by only a factor of two.