1. A method for eyelid shape estimation, comprising: under control of a hardware processor: generating an eye-box over an eye in an eye image, wherein the eye-box is rectangular in shape with an upper edge and a lower edge, wherein the upper edge overlays a portion of an upper eyelid of the eye, and wherein the lower edge overlays a portion of a lower eyelid of the eye; generate a plurality of radial lines extending from approximately the center of the eye-box to the upper edge or the lower edge, determining candidate points on the plurality of radial lines using an edge detector; determining a parabolic fit curve from a subset of the candidate points, wherein the parabolic fit curve is an estimation of an eyelid shape of the eye in the eye image; determining a score of the parabolic fit curve is above a threshold score; and determining that the parabolic fit curve is a preferred estimation of the eyelid shape of the eye in the eye image.