Traditional image interpolation methods separate an image into many sub-blocks. In this case

the quality of the recovered image becomes poor

particularly in the boundary of the blocks and the image borders. To eliminate this side effect

we present a new algorithm based on the 2D all-phase digital signal processing method. First

an algorithm for 2D all-phase windowed processing is designed to achieve three kinds of interpolation kernel based on DFT

DCT

and DWT. The three kernels

which are built directly from the 2D transmission property

can process the frequency distribution along the row and column as well as along the diagonal slope directions. Both and the base window should be confined for phase linearity. The proposed algorithm effectively eliminates the blocking effects and solves the uncontrollable contents in the diagonal slope directions using a traditional technique. In addition

the proposed algorithm improves the PSNR of the recovered images by at least 3 dB. Comparison experiments on the proposed algorithm and six traditional methods show that the proposed algorithm is physically explicit and applicable.