A method for real-time computation of point-by-point apodization coefficients used for beam-forming includes storing apodization coefficients of receiving focus points in memory, and computing at least one of an included angle between a vector from a transducer element to a receiving point and a normal vector of the transducer element, and a trigonometric function value of the included angle. The method also includes addressing the memory storing the apodization coefficients according to the quantized included angle or trigonometric function value, and reading the apodization coefficients. In one embodiment, the method may include computing in advance apodization coefficients of a receiving focus point as the starting point for the subsequent interpolation operation and another receiving focus point as the ending point, and deriving, for each receiving channel, apodization coefficients of the points situated between these two receiving focus points through an interpolation operation.
