1. An apparatus for extracting an edge in an image, comprising: a noise removal unit to remove noise in an input image; a gradient calculator to calculate a gradient of a noise-removed image; a gradient magnitude calculator to calculate magnitude of the gradient; a first stage edge detector to detect, as first stage edges, edges that satisfy a first condition in the noise-removed image using the gradient and the magnitude; and a final edge extractor to extract, as final edges, edges that satisfy a second condition among the first stage edges based on an edge related threshold.