Provide are a methods and devices for processing graphics data in a graphics processing unit (GPU). The method of processing graphics data includes receiving, at a processor, a difference of Gaussian (DOG) layer of an image, detecting, from the received DOG layer, a candidate DOG layer of the image as an intermediate layer, detecting at least one extreme point by comparing values of the candidate DOG layer with values of a previous DOG layer and a next DOG layer, and storing the at least one extreme point in a buffer.