An image processing device comprising: a pattern irradiation unit configured to irradiate an infrared pattern onto a surface of a target object; and an infrared image capturing unit configured to capture an infrared image, wherein the pattern irradiation unit is configured to perform irradiation at a predetermined timing corresponding to an infrared image capturing unit's image capturing timing, and the infrared image capturing unit is configured to obtain a pattern-projected infrared image in which the pattern irradiated by the pattern irradiation unit is projected on the target object, and a pattern-free infrared image in which the pattern is not projected on the target object, wherein the infrared image capturing unit includes two or more infrared image capturing units and the image processing device further comprises: a depth calculation unit configured to perform block matching requiring reduced amount of computation on the basis of pattern-projected infrared images captured from a plurality of viewpoints by the two or more infrared image capturing units, to calculate low-resolution depth information of the target object; and a high-resolution depth calculation unit configured to calculate high-resolution depth information of the target object on the basis of the low-resolution depth information calculated by the depth calculation unit and contour information of the target object extracted from the pattern-free infrared image. a pattern irradiation unit configured to irradiate an infrared pattern onto a surface of a target object; and an infrared image capturing unit configured to capture an infrared image, wherein the pattern irradiation unit is configured to perform irradiation at a predetermined timing corresponding to an infrared image capturing unit's image capturing timing, and the infrared image capturing unit is configured to obtain a pattern-projected infrared image in which the pattern irradiated by the pattern irradiation unit is projected on the target object, and a pattern-free infrared image in which the pattern is not projected on the target object, wherein the infrared image capturing unit includes two or more infrared image capturing units and the image processing device further comprises: a depth calculation unit configured to perform block matching requiring reduced amount of computation on the basis of pattern-projected infrared images captured from a plurality of viewpoints by the two or more infrared image capturing units, to calculate low-resolution depth information of the target object; and a high-resolution depth calculation unit configured to calculate high-resolution depth information of the target object on the basis of the low-resolution depth information calculated by the depth calculation unit and contour information of the target object extracted from the pattern-free infrared image. a depth calculation unit configured to perform block matching requiring reduced amount of computation on the basis of pattern-projected infrared images captured from a plurality of viewpoints by the two or more infrared image capturing units, to calculate low-resolution depth information of the target object; and a high-resolution depth calculation unit configured to calculate high-resolution depth information of the target object on the basis of the low-resolution depth information calculated by the depth calculation unit and contour information of the target object extracted from the pattern-free infrared image.