For fractal image analysis with IDOLON it is necessary to convert a color image to a greyscale or binary image.
The image conversion menu is shown in fig. 5.
Figure 5: Image conversion menu
IDOLON uses a median cut algorithm for the color to greyscale conversion. The popup menu is shown in fig. 6 left, where the Reuse button has to be clicked on to replace the color image with the greyscale image.
Figure 6: Conversion of a color image to a greyscale image and to a binary image
The converted image is shown in fig. 7.
Figure 7: Converted greyscale image
The box counting and 2D variation procedure for binary images (see [4]) both require binary images for the analysis. The conversion of a greyscale to a binary image can be performed in the conversion menu shown in fig. 5. A popup menu is opened to define the threshold of grey values, which should be rendered as black or white. This threshold can be fixed with the mouse. Alternatively the median can be choosen as the threshold.
Fig. 8 shows the histogram for the interactive cutting of the grey values. In the present case the median is taken as the threshold.
Figure 8: Binary cutting of a greyscale image by the median
The Type button is used if another type of the histogram is desired.
The popup menu with the Reuse button, which has to be clicked on, is opened (fig. 6 right).
Fig. 9 shows the binary image.
Figure 9: Binary image