Grid Filter References
Crane, R. (1997) A Simplified Approach to Image Processing: Classical and Modern Techniques in C, Prentice Hall PTR, Upper Saddle River, NJ, 317 pp. ISBN: 0-13-226416-1. ISBN: 9780132264162
Pitas, I. (2000)Digital Image Processing Algorithms and Applications, John Wiley and Sons, New York, 419 pp. ISBN: 0-471-37739-2. ISBN: 9780471377391
Wiggin, Ender (2001) Elementary Digital Filtering, www.gamedev.net/reference/articles/article1068.asp, (09/20/2001).