Projector and projection system

A projector comprising:

• a light source apparatus configured to output light;
• a polarization separator configured to separate the light output from the light source apparatus into first polarized light and second polarized light polarized in a direction different from a direction in which the first polarized light is polarized;
• a first light modulating element configured to modulate the first polarized light separated by the polarization separator;
• a second light modulating element configured to modulate the second polarized light separated by the polarization separator,
• a light combiner configured to combine first modulated light output from the first light modulating element and entering the light combiner with second modulated light output from the second light modulating element and entering the light combiner incident in a direction different from a direction in which the first modulated light enters the light combiner to generate image light;
• and
• a projection optical apparatus configured to project the image light output from the light combiner,
• wherein the first modulated light is light polarized in the same direction as the second polarized light containing a first marker pattern configured with a predetermined bright and dark pattern,
• the second modulated light is light polarized in the same direction as the first polarized light containing a second marker pattern configured with a reversed bright and dark pattern that is a reversed version of the first marker pattern in terms of bright portions and dark portions, and
• the light combiner is configured to combine the first modulated light and the second modulated light with each other in a way that the first marker pattern and the second marker pattern cancel out each other in the image light.