Subpixel accuracy in motion estimation for video coding

The aim is analysis of estimation accuracy for use in hybrid DCT coding schemes. The traditional block-matching algorithm has been generalized in order to take into account displacements of subpixel accuracy: 1, 1/2 and 1/4 pixel accuracies and different interpolation functions have been tested. The prediction error energy has been used to evaluate the performance of the estimation process. The problem has also been approached from the rate distortion theory point of view and the total performance tested considering also the increase in overheads for transmission of the motion vectors. An attempt to overcome the computational complexity of subpixel accuracies has been made. Results have been obtained by simulating a hybrid coder for constant quality coding