Human facial wrinkles can be effectively utilized for facial analysis. It is not an easy task, however, to extract features of wrinkledness directly from a camera image of a human face. For one thing, it is difficult to construct appropriate mathematical models for wrinkle features. In this work, a fuzzy observer is proposed as a means of providing linguistic descriptions about the image of a human face with wrinkles. In the proposed observer, some well-defined classical image features and numerical information are transformed into fuzzy numbers. A feedforward multilayered artificial neural network (ANN) is employed for parameter adjustment of the fuzzy observer based on the available crisp-input fuzzy-output sample sets. An experiment is performed to demonstrate that the facial wrinkles can be indirectly estimated by the proposed fuzzy observer. (C) 2000 Elsevier Science B.V. All rights reserved.