Comparison of different image reconstruction algorithms for synthetic transmit aperture imaging using sparse receiving array

Hadamard encoded Synthetic transmit aperture (H-STA) ultrasound imaging was proposed to provide RF signals with high signal-to-noise ratio (SNR). In this paper, the Hadamard encoded transmission was applied to designing a low-cost ultrasound imaging system by reducing the number of receiving channels and eliminating the delay circuit for transmission. However, reducing the receiving channels compromised the image qualities. To improve the image qualities, we proposed a reconstruction method: synthetic aperture sub-array compounding (SASC). We compared the performance of three image reconstruction methods: regular synthetic aperture (SA) reconstruction, synthetic aperture compounding (SAC) and SASC. SASC presents a good balance between SA and SAC in terms of contrast-noise-ratio and contrast ratio of the hypo-echoic inclusion.