Apparatus and method for performing sub-pixel vector estimations using quadratic approximations
View Patent ↗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.
1. A method to estimate a refined sub-pixel minimum vector position during a frame conversion, the method comprising:
defining a minimum vector position value of a converged vector;
determining a predetermined number of vector correlation samples around the minimum vector position value, the predetermined number of vector correlation samples providing a coarse correlation surface estimation of the minimum vector position value; and
performing 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,
the correlation surface fitting resulting in a refined sub-pixel minimum vector position.
2. The method of claim 1 , wherein the refined sub-pixel minimum vector position has a refined horizontal component.
3. The method of claim 2 , further comprising ascertaining a sub-pixel horizontal refinement of the converged vector from the correlated surface fitting of the predetermined number of vector correlation samples.
4. The method of claim 1 , wherein the refined sub-pixel minimum vector position has a refined vertical component.
5. The method of claim 4 , further comprising ascertaining a sub-pixel vertical refinement of the converged vector from the correlated surface fitting of the predetermined number of vector correlation samples.
6. A apparatus to estimate a refined sub-pixel minimum vector position during a frame conversion, the apparatus comprising:
a computation device, the computation device configured to:
define a minimum vector position value of a converged vector;
determine a predetermined number of vector correlation samples around the minimum vector position value, the predetermined number of vector correlation samples providing a coarse correlation surface estimation of the minimum vector position value; and
perform 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,
the correlation surface fitting resulting in a refined sub-pixel minimum vector position.
7. The apparatus of claim 6 , wherein the refined sub-pixel minimum vector position has a refined horizontal component.
8. The apparatus of claim 7 , wherein the computation device is further configured to ascertain a sub-pixel horizontal refinement of the converged vector from the correlated surface fitting of the predetermined number of vector correlation samples.
9. The apparatus of claim 6 , wherein the refined sub-pixel minimum vector position has a refined vertical component.
10. The apparatus of claim 9 , wherein the computation device is further configured to ascertain a sub-pixel vertical refinement of the converged vector from the correlated surface fitting of the predetermined number of vector correlation samples.