1. A method of processing an image of a three dimensional (“3D”) object having patterns projected thereupon by a beam shaping element, the beam shaping element is capable of shaping different intensity distributions along a finite number of axial planes, where the axial planes are positioned at varied axial ranges, and where the intensity distributions along the axial planes act as constraints in the design of the beam shaping element, the method comprising: obtaining intensity values of a segment of the image; obtaining a first reference lookup table for a first plane from among the finite number of axial planes, and a second reference lookup table for a second plane from among the finite number of axial planes, the first and the second reference lookup tables including reference intensity values at the respective axial plane, the first and second planes are axially adjacent; correlating the intensity values from the segment of the image with respective reference intensity values from the first lookup table to provide a first set of correlation values, and correlating the intensity values from the segment of the image with respective reference intensity values from the second lookup table to provide a second set of correlation values; and interpolating an inter-planner range of the segment of the image between the range to each of the first and the second planes based on the first and the second correlation values.