a method is to implement a scale invariant feature transform algorithm in a shared memory multiprocessing system . the method comprises building differences of gaussian images for an input image , detecting keypoints in the dog images ; assigning orientations to the keypoints and computing keypoints descriptors and performing matrix operations . in the method , building differences of gaussian images for an input image and detecting keypoints in the dog images are executed for all scales of the input image in parallel . and , orientation assignment and keypoints descriptions computation are executed for all octaves of the input image in paralle .