A photosensitive chip, including: at least one set of photosensors substantially aligned in a Y direction; and a layer of non-transmissive material including a plurality of openings. Each opening in the plurality of openings includes a respective center line and overlaps only a portion of a respective photosensor so that only the portion of the respective photosensor is photosensitive. The respective center lines for openings for each set of photosensors are not collinear in the Y direction. In an example embodiment, the plurality of openings includes at least one row of openings substantially aligned in an X direction, orthogonal to the Y direction. In an example embodiment, each opening has an equal width in an X direction, orthogonal to the Y direction.