A method of controlling pixels (134) of at least one spatial light modulator (114) is disclosed. The spatial light modulator (114) has a matrix of pixels (132). Each pixel (134) is individually controllable. The method comprises the following steps: receiving at least one image (331), (342); defining at least one image segment (333) within the image (331),(344); assigning at least one gray scale value to each image segment (333),(348); assigning at least one pixel (134) of the matrix of pixels (132) to each image segment (333),(350); assigning a unique modulation frequency to each gray scale value assigned to the at least one image segment (333),(352); controlling the at least one pixel (134) of the matrix of pixels (132) assigned to the at least one image segment (333) with the unique modulation frequency assigned to the respective image segment (333),(354).