Paintbrush Drawing

This is a freehand drawing technique where the midpoints within a dark band of the interferogram are approximately located and joined the by a smooth curve. It relies exclusively on eye judgment. The paintbrush utility of the window-95 operating system has been employed in this study. The image containing the fringe curves and the original image are subtracted to get the fringe skeleton. Figure 4.24. shows the thinned images corresponding to the interferograms shown in Figure 4.20. Owing to the manual user-interactive approach, the 90 degree projection has an extra fringe over the image generated by the automatic thinning method (Figure 4.20). The superposition of the original interferograms and the fringe skeleton is shown in Figure 4.25. The paintbrush approach has the disadvantage of not locating the minimum intensity location, but does not require code development and hence is reasonably fast.