Patent ID: 7920247

Claim:
A distance measurement system, comprising: a projection apparatus which projects measurement beams at least at first and second projection angles towards a detection area; an image pick-up apparatus which picks up an image of a first reflected light and an image of a second reflected light from the detection area and outputs image signals, the first reflected light corresponding to the measurement beam projected at the first projection angle, and the second reflected light corresponding to the measurement beam projected at the second projection angle; a distance calculation unit which, based on the image signals, calculates a first distance to a first measurement point from a first incidence angle of the first reflected light onto the image pick-up apparatus, the first projection angle and an inter-apparatus distance between the projection apparatus and the image pick-up apparatus, and calculates a second distance to a second measurement point from a second incidence angle of the second reflected light onto the image pick-up apparatus, the second projection angle and the inter-apparatus distance; a judgment unit which judges that specular reflection is caused when the first incidence angle of the first reflected light is equal to the second incidence angle of the second reflected light; and an operation unit which, when it is judged by the judgment unit that the specular reflection is caused, calculates a distance to a detection object causing the specular reflection based on a longest distance among the first distance to the first measurement point and the second distance to the second measurement point and the first and second projection angles when the first and second incidence angles are judged to be equal to each other.