Modified algorithm for two-dimensional convolutions by polynomial transforms

Recently two new methods for computing two-dimensional convolutions by using fast polynomial transforms have been published, by Pei and Wu (1981) and Martens (1982). Analysis shows, however, that it is impossible to obtain the expected higher efficiency with the new methods as compared to the FPT-FFT-CRT algorithm presented by Truong et al. (1981). A modified method is proposed in the letter, with which a gain in efficiency of 2¿5% can be achieved.