A method for determining the validity of a parallax image, including: receiving a parallax image's captured two-dimensional image having at least three target identifiers, where at least two target identifiers are located at different depth planes in the parallax image; identifying at least three target identifiers in the parallax image's captured two-dimensional image and determining spatial relationship between at least three target identifiers in the two-dimensional image of the parallax image; comparing the spatial relationship of at least three target identifiers in the parallax image's captured two-dimensional image against a predetermined spatial relationship of at least three target identifiers that indicates authenticity; and adjudicating the authenticity of the parallax image based on the degree of difference between spatial relationship of at least three target identifiers in the parallax image's captured two-dimensional image and the predetermined spatial relationship of at least three target identifiers.