[Octave-bug-tracker] [bug #52933] [octave-forge] (image) regionprops Perimeter returns Matlab incompatible results

[Hartmut]

Follow-up Comment #9, bug #52933 (project octave):

Oh, I thought your code was already ment to be Matlab compatible. What a
pity.

But if they are really calculating the perimeter now as some funny linear
combination of the three numbers "even", "odd" and "corners" it should be easy
to figure out what coefficients they use.

If you have access to a recent enough Matlab, then please do the following
calculations:


format long
M = [1 0 0 2 0 3;
     1 0 2 0 0 3;
     0 0 0 0 0 3;
     0 0 0 0 3 3]
props = regionprops(M, 'perimeter');
props.Perimeter


The Even, Odd and Corners of those three regions should be (please double
check):
* (E, O, C) = (2 0 2) in region 1,
*           = (0 2 2) in region 2, and
*           = (6 1 4) in region 3

Since the above three vectors are linearly independent (I think so) you should
then be able to calculate the three unknown coefficients (currently taken as
+0.980, +1.406, -0.091) from those results.

Let me know if this doesn't work out.

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