Techniques of fringe interpolation in moiré patterns

The objective of this paper is to report further developments on the application of the displacement-light-intensity law to fractional-fringe-order determination. The structure of moiré-fringe patterns is analyzed when the moiré fringes are recorded together with the lines producing them. A device used to record the information stored in the film is described. The influence of the combined effect of the film and the reading device is discussed. Departures from the ideal behavior of the whole process are analyzed together with the introduced errors. The mechanics of processing continuous moiré-fringe information is outlined together with the means utilized to reduce the influence of errors. Data are provided to show the degree of effectiveness achieved with the described process.