IMAGE PROCESSING—CONTINUOUS TO DISCRETE. Volume 1. GEOMETRIC, TRANSFORM AND STATISTICAL METHODS, by Edward R. Dougherty and Charles R. Giardina. Prentice-Hall, Englewood Cliffs, N.J., 1987. XI+ 452 pp. MATRIX STRUCTURED IMAGE PROCESSING, by Edward R. Dougherty and Charles R. Giardina. Prentice-Hall, N.J, 1987. X + 258 pp.