To perform spacing and persistance estimations, select Acquisition => Spacing and persistance estimations. This opens the InfoBox window in which three independant estimations are displayed (Figure 9 below).
The first one follows Jaboyedoff (personal communication 1991). In this case, a contour window must be drawn on the window, as it is used in the computation scheme. The only difference with Jaboyedoff et al. (1996) resides in the computation of the number of discontinuities per surface unit. In this case : n = n0 + 0.5n1
The second one follows Jaboyedoff et al. (1996). In this case, a contour window must be drawn on the window, as it is used in the computation scheme.
The third estimation is after Pahl (1981). In this case the contour window is not necessary, but a rectangular window must be drawn.
Below these two estimations, the InfoBox also displays the picture of the elements drawn on the acquisition window. The content of the InfoBox can be saved using the Save toolbar button or the File => Save or File => Save as menus.
Figure 9 : InfoBox displaying spacing - persistance information and the corresponding digitized image (reduced)