A new approach for the design of optimal pseudoinverse filter for ultrasonic applications is presented. The filter is derived from the spatio-temporal impulse response of the US system at scatterer locations (assumed to be on a uniform grid) in the region of interest (ROI). We provide a derivation for the filter coefficients based linear formulation of the pulse propagation from the scatterers to the transducer. In this paper, we show the frequency response of the derived filter using experimental data and we demonstrate that the new formulation does indeed behave as an inverse filter (i.e., it provides spectral inversion in the passband of the original system). However, for coded-excitation systems, the pseudoinverse can be derived for 2D and 3D imaging. This approach will provide the opportunity for simultaneous acquisition of many image lines upon each transmit. Thus, it can be used to increase the frame rate of ultrasound imaging systems.