Apparatus and method for performing sub-pixel vector estimations using quadratic approximations

To achieve the foregoing, and in accordance with the purpose of the present invention, an apparatus and method for generating refined sub-pixel vectors for motion estimation from vector correlation values and converged vector correlation values using quadratic approximations respectively is disclosed. The apparatus and method includes defining a minimum vector position value of a converged vector and then determining a predetermined number of vector correlation samples around the minimum vector position value. The predetermined number of vector correlation samples provide a coarse correlation surface estimation of the minimum vector position value. A correlation surface fitting of the predetermined number of vector correlation samples using a quadratic approximation of the coarse correlation surface estimation of the minimum value is then performed. The correlation surface fitting resulting in a refined sub-pixel minimum vector position with horizontal and vertical components.