INTER-REFLECTION DETECTION APPARATUS, INTER-REFLECTION DETECTION METHOD, AND PROGRAM

Provided is an inter-reflection detection apparatus including: an irradiation unit configured to emit light having variable-frequency sinusoidal patterns; an image acquisition unit configured to acquire an image of an object irradiated with the light from the irradiation unit; a phase determination unit configured to determine a phase at each position in the image; and a detection unit configured to detect a region in which inter-reflection occurs. The detection unit is configured to determine a phase difference between a phase acquired from an image generated by irradiation of a low-frequency sinusoidal pattern and a phase acquired from an image generated by irradiation of a high-frequency sinusoidal pattern for a plurality of combinations of low-frequency waves and high-frequency waves, and determine that inter-reflection occurs in a region in which the phase difference for any one of the plurality of combinations is equal or more than a threshold.