Closing by Reconstruction Example


This morphological operator does the reconstruction of an image from another marker image. The operator applies a serie of conditional erosions on the marker image (second input) using the original image as the conditional image (first input). As the conditional erosion operator is necessary, a third input, a structuring element is mandatory.

On binary images it is very useful to extract features using markers. In the example bellow the goal is to extract only the digits 1 and 4 from the image shown in figure 1. Note that they both have a | in common so it is very easy to make markers to them (using some erosions for instance). Figure 2 shows the markers. The final result is shown in figure 3.

   1 1 1
   1 1 1  Structuring element used
   1 1 1

fig. 1 - Original Image

fig. 2 - Marker Image

fig. 3 - Final Result

In the image bellow we show a 1D signal (blue) that was subtracted by a constant resulting the plot yellow (the marker image). The reconstruction is the discrete red plot.

   0 0 0
   1 1 1  Structuring element used
   0 0 0

fig. 4 - Combined signals



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