Reducing number of elements of transducer arrays in Fourier image construction method

In this paper, we study quantitatively the relationship between the quality of images constructed with the Fourier method and the element spacing of array transducers. In the study, two linear arrays were used. Effective larger element spacings were obtained by combining signals from adjacent elements. Both computer simulation and experiment were performed. Results show that resolution of constructed images is not affected by the reduction of number of elements, but the contrast of images is decreased dramatically when the element spacing is larger than about 2.365λ, where λ is the wavelength. This suggests that an array of about 2.365λ spacing can be used with the Fourier method. This reduces the total number of elements of a fully sampled 128×128 array (0.5λ spacing) from 16384 to about 732