Processing of color image data using directional information has received increased attention lately due to the introduction of the vector directional filters. These rank-ordered type filters utilize the direction of color vectors to enhance, restore and segment color images. First, the different vector directional filters already in use are presented, focusing on their similarities and differences and, second, new adaptive vector directional filters are introduced. Fuzzy as well as nearest neighbor structures are utilized to determine the weights in the proposed adaptive filters. Simulation studies involving color images are used to assess the performance of the different vector directional filters and to compare them win other commonly used nonlinear filters. The simulation studies reported indicate that the new adaptive filters are computationally attractive and have excellent performance. © 1997 Society of Photo-Optical Instrumentation Engineers.
Plataniotis, K. N., Androutsos, D., & Venetsanopoulos, A. N. (1997). Color image filters: The vector directional approach. Optical Engineering, 36(9), 2375-2383.