Gm Global Technolgoy Operations, Inc.

Ford Global Technolgoies, LLC

Gary C Barber

Arup Kumar Gangopadhyay

Jie Gu

Simon Chin-Yu Tung

Han Zhao

A contour measurement system determines three dimensional surface information of an object using a projection moir&eacute; technique to obtain a single fringe pattern that is analyzed using a phase-shift image processing method. A grating is projected onto the object and the reflected fringe pattern is recorded by a camera and stored digitally as an array of pixels. An estimated fringe spacing is then determined for each pixel. Using the estimated fringe spacings, four phase-shifted fringe patterns are generated by correlation integration and then used in a phase calculation to obtain wrapped phase information for the object. This phase information is then unwrapped and normalized, producing a set of data points representative of the unwrapped phase information. Noise suppression using pattern reconstruction and smoothing can be utilized at this point to improve the signal to noise ratio. Thereafter, updated estimated spacings are determined for each data point using a curve fitting function such as a localized least squares fit. The system then performs one or more additional iterations of the correlation integration, phase calculation, unwrapping, noise suppression, and fringe spacing update steps, each time using the newest updated estimated spacing in the correlation integration. After the final iteration, the unwrapped phase information is demodulated and used to calculate the three dimensional coordinates of points on the object surface. A fractional pixel analysis technique is also disclosed for use in the correlation integration and updated estimated spacing calculations.

Image processing method using phase-shifted fringe patterns and curve fitting

A method of reducing cutting tool wear in a lubricated metal cutting operation has been developed. An electrical cutting cell is provided having an anodic conductive cutting tool and a cathodic conductive work-piece connected to a DC current supply; the lubricant contains platable wear reducing agents. The lubricant is located to bathe the contacting interface between the cutting tool and work-piece to constitute an electrolyte. Next, the electrical current flow through the contacting interface is controlled to be in the range of 25-500 milli-amps. Lastly, the cutting tool is moved into and along cutting contact with the work-piece while current flows there-between to electro-chemically deposit the wear reducing agents on at least the contacting interface to reduce cutting tool wear and improve ease of mass removal.

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Novi, MI, United States of America

Gary C Barber