Perimeter definitions

MaurizioIEC

Hi Guys,
I would like know which is the difference between the Perimeter bounding pixel and the  Perimeter bounding polygon.
The 1st is based on a Daisy chain perimeter pixel calculation, what about the 2nd?
How the Perimeter bounding polygon is calculated?
It is often different to the Perimeter bounding pixel value.
Thank you in advance for the information you will provide.
ciao
Maurizio

MaurizioIEC

Thanks Craig,
your was the explanation I was looking for.
Ciao
Maurizio

CraigW

The "Perimeter, Bounding Pixels" measurement is basically a count of the boundary pixels under the measurement outline with a correction for diagonal transitions; when a spatial calibration is present on the image, these counts are adjusted to reflect the calibrated size of a pixel.  The "Perimeter, Bounding Polygon" measurement is an actual direct measurement of the sum of the calibrated lengths of the vertices of the bounding polygon.  By default, the bounding vertices of a Count/Size detected boundary are placed on the centers of the bounding pixels of the object being segmented.  However if the Measurement Options->Outlines->Outline Pixels box is checked, then the detected boundary is placed on the outside of bounding pixel tiles, leading to a larger measured "Perimeter, Bounding Polygon" (as well as a larger "Area, Polygon") measurement.

mbatchelor

2017-05-15-111555

Maurizio --

You have probably already seen that there is a "definition" that appears when the mouse is hovered over a MEASUREMENT.

If you have not seen this, the "definitions" for the PERIMETER MEASUREMENTS are shown below.

I hope this information is helpful.

-- Matt

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