Shifted Linear Interpolation Filter

Linear interpolation has been adapted in many signal and image processing applications due to its simple implementation and low computational cost. In standard linear interpolation the kernel is the second order B-spline   2 β t . In this work we show that the interpolation error can be remarkably diminished by using the time-shifted B-spline   2 β t Δ as an interpolation kernel. We verify by experimental tests that the optimal shift is 0.25 Δ= . 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.