Abstract: A time-delay and integration camera assembly (A) is mounted to view a rotating or other cyclically moving object (B). A lens (30) focuses light from a field of view (10) onto an array (32) of light sensitive elements having N lines of elements. A tachometer (50) monitors rotation of the rotating object and a timing control (54) causes a light sensitive array control (34) to start stepping lines of data along the lines of light sensitive elements toward a shift register (36) as a leading edge (20) of a region of interest (12) enters the field of view. Each time the region of interest moves 1/Nth of the way across the field of view, the lines of data are stepped another time along the lines of light sensitive elements. Digital video signals are sorted (74) among a plurality of image memories (76.sub.1, 76.sub.2, . . . , 76.sub.M) each image memory corresponding to a corresponding region of interest (12.sub.1, 12.sub.2, . . . , 12.sub.M).