Comments on "A three-module strategy for edge detection" [with reply]

Comments are made on the above named work by V. Lacroix (see ibid., vol.10, no.6, p.803-10, 1988). The commenters contend that the proposed orthogonal bases are the same as the edge subspace bases in the approach of W. Frei and C.C. Chen (IEEE Trans. Comput., vol.C-26, no.10, p.988-98, 1977) and that the ratio for detecting edges is the same as that proposed by Frei and Chen for special cases. In his reply, Lacroix explains the relationship between his method and that of Frei and Chen.<>