An optical detection system for detecting data on the optical mutual coherence function of input field. The system comprising an encoder having similar unit cells, and an array of sensor cells located at a distance downstream of said unit cells with respect to a general direction of propagation of input light. The array defines a plurality of sub-array unit cells, each sub-array corresponding to a unit cell of the encoder, and each sub-array comprising a predetermined number M of sensor elements. The encoder applies predetermined modulation to input light collected by the system, such that each unit cell of said encoder directs a portion of the collected input light incident thereon onto sub-array unit cell corresponding therewith and one or more neighboring sub-array unit cells within a predetermined proximity region. The number M is determined in accordance with a predetermined number of sub-arrays unit cells within the proximity region.