Open image file leaves.png, which is present in the Digimizer\Sample Images subfolder in the My Documents folder.
Select Contrast autofix in the Image menu. This will automatically maximize the contrast in the image.
The image contains a ruler which we will use to calibrate our measurements.
Select the Zoom in tool.
Drag a rectangle over the ruler so it is enlarged.
Select the Unit tool.
Click on the small vertical line above the value 0 and next click on the line above the value 10.
A dialog box is displayed in which we enter the real length of the unit line: 10 cm.
Click the Zoom to fit tool.
Select Binarization in the Binary menu. The following dialog box is displayed:
The dialog box displays a histogram of gray levels. A red line indicates the default threshold value.
Click Preview. All gray levels below the threshold value will become red (indicating an object), those above white (indicating background).
Click OK to accept the threshold value.
Select Analyze Objects in the Binary menu. Complete the dialog box as follows (a minimum area of 3 cm2 is required for an object to be identified as a leaf):
The leaves are now outlined.
The characteristics of the 6 leaves are displayed in the measurements list, and the mean area and perimeter are displayed in the statistics window:
Select Hide Binary layer in the Binary menu so you can judge how well the areas fit the leaves.
