A complex discrete wavelet transform for processing quadrature Doppler ultrasound signals

Unlike the conventional discrete wavelet transform discrete complex wavelet transform is a shift invariant transform with limited redundancy. Quadrature Doppler ultrasound signals are dual channel signals obtained from the systems employing quadrature demodulation. Prior to processing Doppler signals by using discrete Wavelet transform, directional flow signals must be obtained and then two separate transform applied, increasing the computational complexity. In order to decrease computational complexity, a complex discrete wavelet transform algorithm is proposed. A comparison between the new transform and the conventional technique is presented. The results show that the proposed method gives the same output as the conventional technique and the computational complexity for processing quadrature signals using discrete complex wavelet transform is greatly reduced.