Camera intrinsic calibration

A system for determining intrinsic parameters of a plurality of cameras, the system comprising:

• a plurality of cameras;
• a plurality of collimator assemblies, wherein each camera is placed in front of one of the plurality of collimator assemblies, wherein each collimator assembly includes a two-sided diffractive optical element, wherein a grating pattern is formed on each surface of the two-sided diffractive optical element;
• and
• a processor coupled to the plurality of cameras to receive image data from the plurality of cameras, wherein the processor stores executable instructions that, when executed by the processor, cause the processor to:
• for each camera among the plurality of cameras:
• receive an image from the camera, wherein the grating pattern formed on each surface of the two-sided diffractive optical element is selected to reduce a brightness of a central intensity peak on the image to a predetermined amount;
• identify data pairs, each data pair including pixel coordinates of an intensity peak on the image and virtual light source formed by the two-sided diffractive optical element that corresponds to the intensity peak;
• and
• determine intrinsic parameters of the camera using the identified data pairs for the image.