Characteristics of minimax FIR filters for video interpolation/decimation

Examines the distinctive features of 2D diamond-shaped filters, a class of filters quite important for video interpolation/decimation. The geometrical interpretation of linear programming is proposed as an easy tool for understanding the characteristics of M-D FIR filters minimax optimal and the effects of the constraints most common in video application. The relationships between minimax error, filter orders and bandwidth of diamond-shaped FIR filters are investigated, extending results typical of 1D minimax filter design. The effect of constraining one of the filter orders to a pre-assigned value (provision quite useful if the filter order under consideration determines the number of frame-stores) is studied extensively. In light of the reported characteristics of the diamond-shaped FIR filters their multistage implementation becomes extremely attractive. The advantages and the potential of multi-stage implementation of diamond-shaped filters are discussed