Shifted linear interpolation filter

Linear interpolation has been adapted in many signal and image processing applications due to its simple implementa-tion and low computational cost. In standard linear interpolation the kernel is the second order B-spline β₂(t). In this work we show that the interpolation error can be remarkably diminished by using the time-shifted B-spline β₂(t)-Δas an interpolation kernel. We verify by experimental tests that the optimal shift is Δ=0.25. In VLSI and microprocessor circuits the shifted linear interpolation (SLI) algorithm can be effectively implemented by the z-transform filter. The interpolation error of the SLI filter is comparable to the more elaborate higher order cubic convolution interpolation.