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A nondestructive method based on spectroscopic ellipsometry has been developed and demonstrated for the real-time measurement of a single pulp fiber's microfibril angle and phase retardation, with the latter proportional to the cell wall thickness. The method uses an optical arrangement insensitive to the sample's orientation in combination with a proper spectral analysis of the sample's image. The optical arrangement and the measurement principle of the method are described. To test the new method, equipment functioning as a spectroscopic imaging ellipsometer was constructed according to the arrangement, and measurements were carried out in which single pulp fibers and ordinary wave plates were measured. The test measurements and results are described and presented. OCIS codes: 120.2130, 120.6200, 160.4760, 300.6190.

We have realized a novel optoelectronic implementation of an analog fuzzy-inference architecture, using the movement of the center of gravity of a far-field pattern. In the inference process Gaussianlike membership functions and a product-sum-gravity method are used. Antecedent membership functions and the grade evaluations are realized by combining light-emitting-diode (LED) arrays for sequential light emission and position-sensing devices for center-of-gravity detection. Consequent and defuzzification operations are realized by a LED array and a position-sensing device. High-speed fuzzy inference of more than several tens of mega fuzzy logical inference per second is possible with these units. The usefulness of the system is demonstrated by the real-time standing control of an inverted pendulum. Key words: Optoelectronic, fuzzy, control, LED, position-sensing device.