METHODS AND APPARATUS FOR ESTIMATING ORIENTATION IN AN IMAGE

Methods and apparatus for estimating an orientation are disclosed. Methods of estimating an orientation include: dividing a fingerprint image into first partial regions, measuring the gradient of each pixel of the fingerprint image, and estimating a representative orientation of each of the first partial regions; obtaining an improved fingerprint image by filtering the fingerprint image using a double orientation filter, and remeasuring the representative orientation of each of the first partial regions by remeasuring the gradient of each pixel of the improved fingerprint image; and dividing the first partial regions into second partial regions, and estimating the representative orientation of the second partial regions with respect to the curvatures of the first partial regions in response to the remeasured representative orientation of each of the first partial regions and the remeasured gradients of the pixels.