import { Keypoint } from '../core/Keypoint';
/**
 * SubPixel interpolation based on a 3x3 window
 */
export declare function subPixel2D(s_0_0: number, s_0_1: number, s_0_2: number, s_1_0: number, s_1_1: number, s_1_2: number, s_2_0: number, s_2_1: number, s_2_2: number): Keypoint;