Calibration apparatus, projector and calibration method

An apparatus comprising:

• a location-and-attitude estimation unit configured to, based on an image taken of a surface of an object having a location and an attitude, light rays being projected onto the surface, estimate the location and the attitude of the surface;
• a reflection-point estimation unit configured to estimate, based on the estimated location and the estimated attitude, a reflection point at which one of the light rays is reflected by the surface;
• and
• an identification unit configured to identify both a passing point that the one of the light rays passes and a direction in which the one of the light rays passes the passing point, or to identify only the direction, based on a plurality of reflection points that are obtained by the reflection-point estimation unit with respect to a plurality of different locations and/or a plurality of different attitudes of the surface.

A method comprising:

• a location-and-attitude estimation step of estimating, based on an image taken of a surface of an object having a location and an attitude, light rays being projected onto the surface, the location and the attitude of the surface;
• a reflection-point estimation step of estimating, based on the estimated location and the estimated attitude, a reflection point at which one of the light rays is reflected by the surface;
• and
• an identification step of identifying both a passing point that the one of the light rays passes and a direction in which the one of the light rays passes the passing point, or identifying only the direction, based on a plurality of reflection points that are obtained in the reflection-point estimation step with respect to a plurality of different locations and/or a plurality of different attitudes of the surface.