1. A distance image acquisition apparatus comprising: a projection unit which projects a first pattern of structured light distributed in a two-dimensional manner with respect to a subject within a distance measurement region in a plurality of wavelength bandwidths; an imaging unit which is provided in parallel with and apart from the projection unit by a baseline length, performs imaging with sensitivities to the plurality of wavelength bandwidths, and generates a plurality of captured images including the first pattern reflected from the subject and corresponding to the plurality of wavelength bandwidths; a determination unit which determines whether or not a second pattern of structured light projected from another distance image acquisition apparatus is included in the captured images; a pattern extraction unit which extracts the first pattern from at least a captured image determined as the second pattern being not included by the determination unit; and a distance image acquisition unit which acquires a distance image indicating a distance of the subject within the distance measurement region based on the first pattern extracted by the pattern extraction unit, wherein the first pattern and the second pattern are dot patterns, and in a case where the number of dots of a dot pattern in the captured image exceeds the number of dots of the first pattern projected from the projection unit, the determination unit determines that the second pattern is included in the captured image.