An information processing system, comprising: a light emitting unit (8, 8a) that is adapted to irradiate pattern light having a specific pattern to a subject to form a texture on the subject; an imaging unit that is adapted to capture the subject on which the texture is formed; a deriving unit that is adapted to derive distance information to the subject based on an image captured by the imaging unit; an analyzing unit that is adapted to analyze whether or not an image abnormality is present in either one of the captured image and an image based on the distance information; a setting unit that is adapted to set information about the subject; and a dimming unit that is adapted to perform dimming control of the pattern light when the analyzing unit analyzes that the image abnormality is present, wherein a calculating unit (53, 61) is adapted to change a size of the reference region in the reference image in accordance with the information about the subject; and the imaging unit includes a first imaging unit that is adapted to capture the subject to generate a reference image, and a second imaging unit that is arranged at a position different from a position where the first imaging unit is arranged, and that is adapted to capture the subject to generate a comparison image, the deriving unit includes the calculating unit (53, 61) that is adapted to calculate a matching degree between a region in the reference image and a region in the comparison image, the deriving unit is adapted to derive as the distance information, a parallax value that identifies a region in the comparison image corresponding to a reference region in the reference image, based on the matching degree calculated by the calculating unit (53, 61), and the information processing system further comprises a generating unit that is adapted to generate a parallax image based on the parallax value, wherein the analyzing unit is adapted to analyze whether or not the image abnormality is present in the captured images and in the parallax image. a light emitting unit (8, 8a) that is adapted to irradiate pattern light having a specific pattern to a subject to form a texture on the subject; an imaging unit that is adapted to capture the subject on which the texture is formed; a deriving unit that is adapted to derive distance information to the subject based on an image captured by the imaging unit; an analyzing unit that is adapted to analyze whether or not an image abnormality is present in either one of the captured image and an image based on the distance information; a setting unit that is adapted to set information about the subject; and a dimming unit that is adapted to perform dimming control of the pattern light when the analyzing unit analyzes that the image abnormality is present, wherein a calculating unit (53, 61) is adapted to change a size of the reference region in the reference image in accordance with the information about the subject; and the imaging unit includes a first imaging unit that is adapted to capture the subject to generate a reference image, and a second imaging unit that is arranged at a position different from a position where the first imaging unit is arranged, and that is adapted to capture the subject to generate a comparison image, the deriving unit includes the calculating unit (53, 61) that is adapted to calculate a matching degree between a region in the reference image and a region in the comparison image, the deriving unit is adapted to derive as the distance information, a parallax value that identifies a region in the comparison image corresponding to a reference region in the reference image, based on the matching degree calculated by the calculating unit (53, 61), and the information processing system further comprises a generating unit that is adapted to generate a parallax image based on the parallax value, wherein the analyzing unit is adapted to analyze whether or not the image abnormality is present in the captured images and in the parallax image.