Reconfigurable Color Doppler DSP Engine for High-Frequency Ultrasonic Imaging Systems

Abstract

A single-chip reconfigurable Color Doppler DSP engine is presented. It acts as the computation kernel of the highfrequency ultrasonic imaging system under development.The flexibility of the proposed DSP engine enables users to acquire sufficient information as needed, while the specificity of the hardware compared to general-purpose processors reduces cost and power consumption. This chip is implemented by TSMC 0.18 [tm I1P6M CMOS technology.The die size is 2.94*2.94 mm2, and the power consumption is 184 mW when frame rate = 50, frame size = 512*256, and packet size = 8. Fig. 1. Color Doppler blood flow image [6].Index Terms-Color Doppler, DSP, Ultrasound quite expensive. To meet the large computational and data bandwidth needs in Color Doppler imaging, dedicated 1. INTRODUCTION hardware design is required to reduce area and power consumption while provide valuable information in real time. Ultrasound imaging is a well-established imaging modality To the best of our knowledge, there is no high-frequency that provides diagnostic information in the form of cross-(>20MHz) Color Doppler ultrasonic system ever published. sectional images of soft tissue. It has the advantages of cost-The proposed DSP engine is the computation kernel of our effectiveness, non-invasiveness, rapid imaging and developing high-frequency Color Doppler imaging system, portability. However, for many clinical applications which is significant to clinical and research fields. involving subtle tissue structure, the resolution of conventional ultrasound imaging systems that operates 2. PROPOSEDVLSIARCHITECTURE between 2 and 10 MHz is inadequate [1]-[2]. Moreover, small animal models have been used extensively in In high-ffrequency ultrasonie imaging systems, in which the genomics research, drug development, and developmental ultrasound frequency is generally greater than 20 MHz, the biology, which also demand near-microscopic resolution major design problem is eaused by strong attenuation of [3]-[4]. Therefore, recent developments have taken the tissues, whieh limits the maximum depth of penetration and advantage of the fact that resolution increases linearly with the achievable signal to noise ratio (SNR). Moreover, the frequency. That is to say, improved spatial resolution is the high sampling rate and smaranse size further reduee need that drives the development of higher frequency the SNRperformance.nsummary,noiseisthemajorenemy ultrasonic imaging systems. Doppler ultrasound, which weneed to conquer. measures blood flow using Doppler effect, is a non-invasiveThe block diagram of proposed VLSI architecture is technique for velocity measurements of blood flow [5].shownin Fig. 2. In this diagram, only flow parameter Color Doppler imaging ( Fig. 1 [6]) is a well-established estimation is for deriving the required flow parameters. The Doppler ultrasound mode and very valuable for visualizing other blocks are either for suppressing noises or improving in real time the distribution of blood flow in a specific image quality In the following sections...