Fuzzy data processing method and data smoothing filter

• US 5,398,303 A
• Filed: 02/28/1992
• Issued: 03/14/1995
• Est. Priority Date: 02/28/1992
• Status: Expired due to Fees

• Current Assignee: Yamatake-Honeywell Company Limited
• Original Assignee: Yamatake-Honeywell Company Limited
• Inventors: Tanaka, Masato
• Primary Examiner(s): Downs, Robert W.
• Application Number:
  US07/843,751
• Time in Patent Office: 1,110 Days
• Field of Search: 395/10, 395/3, 395/51, 395/61, 395/900
• US Class Current: 706/45
• CPC Class Codes: G05B 23/0221 Preprocessing measurements, e.g. data collection rate adjustment; Standardization of measurements; Time series or signal analysis, e.g. frequency analysis or wavelets; Trustworthiness of measurements; Indexes therefor; Measurements using easily measured parameters to estimate parameters difficult to measure; Virtual sensor creation; De-noising; Sensor fusion; Unconventional preprocessing inherently present in specific fault detection methods like PCA-based methods
• CPC Class Codes: Y10S 706/90 Fuzzy logic

Abstract

A unique data processing method and a fuzzy smoothing filter are disclosed which employ a three-dimensional elliptic membership function based on the fuzzy logic to remove noises from data including a sequence of measured points for evaluating the linearity of the measured points. The evaluation is carried out by superimposing the center of an ellipse represented by an elliptic membership function on a substantial central portion of inputted data, evaluating a factor representing the linearity of the inputted data by summing the degrees of membership derived at respective inputted data, calculating the ratio of the factor to a factor representing an ideal linearity of the inputted data, rotating the ellipse by a predetermined angular distance to derive the ratio at that position, repeating the rotating step until the peak is found, and determining the ratio when the peak is found as the linearity of the inputted data. The fuzzy smoothing filter is comprised of a data input for inputting data to be smoothed, a multi-dimensional membership function generator for calculating a degree of membership for the inputted data, a calculator for deriving an angle of the data and calculating the linearity of the data, smoothing processors coupled to receive the angle and the linearity of the data from the calculator for executing a smoothing operation in a plurality of modes, a selector for selecting one mode from among the plurality of smoothing modes, and a store for holding smoothing filter parameters supplied to the calculator and the selector.

Claims

1. A fuzzy smoothing filter for smoothing data including a sequence of measured points plotted in an orthogonal coordinate system comprising:

a data input means for inputting data to be smoothed including a plurality of data points;

a multi-dimensional membership function generating means for calculating a degree of membership for said inputted data;

a calculation means for deriving an angle of said data and calculating the linearity of said data;

smoothing means coupled to receive the angle and the linearity of said data from said calculation means for executing a smoothing operation in a plurality of modes;

a selector means for selecting one mode from among the plurality of smoothing modes; and

a storage means for holding smoothing filter parameters supplied to said calculation means and said selector means.