A simple method for optically implementing digital logic gates in parallel has been developed. Parallel logic gates can be achieved by using a lensless shadow-casting system with a light emitting diode array as an incoherent light source. All the sixteen logic functions for two binary variables, which are the fundamental computations of Boolean algebra, can be simply realized in parallel with these gates by changing the switching modes of a LED array. Parallel computation structures of the developed optical digital array processor are demonstrated by implementing pattern logics for two binary images with high space-bandwidth product. Applications of the proposed method to parallel shift operation of the image, differentia-tion, and processing of gray-level image are shown.