Showing papers in "Journal of Japan Society for Fuzzy Theory and Systems in 1996"

An Exposure Control System of Video Cameras Based on Fuzzy Logic Using Color Information

Abstract: Auto exposure (AE) is an important function of video cameras to adjust the image luminance. In this paper, an exposure control system of the AE using color information is discussed. Current AE systems detect special image conditions such as backlighting and excessive frontlighting in which the luminance of a main object deteriorates, and compensate the exposure in order to obtain the appropriate luminance of the main object. The compensation is determined according to the degree of backlighting and excessive frontlighting, regardless of the the background. The exposure control system proposed in this paper uses "hue" and "chroma" of pixels to derive the importance of the background, and determines the amount of compensation required by fuzzy reasoning. Simulations of AE were carried out using both the conventional system and proposed method. Results showed that the proposed system was more efficient for AE than the conventional method.

Precise Speed Control of Ultrasonic Motors by Repetitive Control with Fuzzy Reasoning

Abstract: Ultrasonic motor is a new type motor and it has many useful features. This motor, how­ever, has large speed ripple which arises from inherent natures caused by its driving principle and structure, and it is a significant problem in view of precise speed control. In this paper, we pay attention to periodic­ity of the speed ripple and reduce the speed ripple by repetitive control with variable learning factor based on fuzzy reasoning. The effectiveness of proposed control scheme is demonstrated by experiments.

An Adaptive Rule Extraction with the Fuzzy Self-Organizing Map and a Comparison with Other Methods

Abstract: For automatic rule extraction from a set of input-output data examples, decision tree generating methods such as ID3 and fuzzy ID3 play a major role. These methods, however, are difficult to apply when there is a tendency for the examples to change dynamically. This paper presents a new method for adaptive rule extraction with the fuzzy self-organizing map and the results of simulations in order to present its effectiveness by a comparison with other methods such as RBF (radial basis functions) and GA (genetic algorithms). We obtained the result that our method is superior to other methods for automatic and adaptive rule extraction.