1. A method for generating image data in an ultrasound scanning process using a CAC-BF technique, comprising: transmitting a set of shots associated with a set of subarrays or subapertures of an available transducer array or aperture in a predetermined sequence; receiving echoes of the respective shots; coarse beamforming the received echoes to generate a plurality of range lines; and fine beamforming the range lines to produce coherent image data, the fine beamforming including weighting the range lines.