Select these parameters to compute the perimeter of objects and its horizontal, vertical, and diagonal components. In blob measurements the perimeter is calculated by counting the number of boundary pixels: Three types of boundary pixels are identified: those forming the horizontal boundaries, those forming the vertical boundaries, and the corner pixels. The number of pixels in each category is used to calculate PerimX, PerimY and PerimXY accordingly:
The following formulas are utilized in perimeter calculations:
Where:
is the number of pixels forming the horizontal boundary of the object
is the number of pixels forming the vertical boundary of the object
is the number of corner pixels forming the diagonal boundary of the object
is the horizontal spatial resolution in units per pixel (1 if image is not calibrated)
is the vertical spatial resolution in units per pixel (1 if image is not calibrated)
If objects contain holes, the internal boundaries contribute to the perimeter of the objects. In the filed measurements these parameters measures the total perimeter of objects in each phase.
In contour measurements the accumulated length of the contour segments is used to calculate Perim, and their horizontal and vertical projections are used to determine PerimX and PerimY respectively.