1. A method of processing an image, the method comprising: preparing, using at least one processor, a three-dimensional (3D) hand model database comprising 3D hand models with lengths of size features; receiving from a camera configured to capture an image of a first hand, a first two-dimensional (2D) hand image obtained by capturing an image of the first hand; converting color information of pixels included in the first 2D hand image into monochrome information; extracting, using the at least one processor, a feature vector from an analysis of the first 2D hand image based on the monochrome information, the feature vector corresponding to a position of the first hand; determining a parameter from the analysis of the first 2D hand image, the parameter corresponding to an estimated size feature of the first hand; and detecting a first 3D hand model corresponding to the first 2D hand image by using the parameter and the feature vector to search the 3D hand model database, wherein the estimated size feature comprises an estimated length of a portion of the first hand, wherein the detecting comprises: detecting the first 3D hand model in the 3D hand model database by comparing the estimated size feature with a size feature of the first 3D hand model; detecting at least one candidate region corresponding to the first hand from the first 2D hand image; performing a first masking on a remaining region obtained by excluding a first candidate region selected from the at least one candidate region from a second 2D hand image; detecting a first 3D hand model candidate based on the second 2D hand image obtained by performing the first masking; and selecting the first 3D hand model based on the first 3D hand model candidate, and wherein the detecting of the at least one candidate region comprises detecting at least one region in which movement is detected from the first 2D hand image.