Cell orientation measurement

Hello,

I have a question concerning the orientation measurement in the module: MeasureObjectSizeShape.

I have pictures with cell nucleis, recognition of objects works fine. The thing that I dont understand is what the orientation measurement really represents. Does it measure the orientation of each object recognized and then average it? Or does it fit an ellipse around all the objects recognized and give the orientation of this single ellipse? Because the definition is not very clear.

Any help would be very precious.

Thank you in advance

Jonathan

Hi Jonathan,

The documentation for MeasureObjectSizeShape says the orientation is “the angle (in degrees ranging from -90 to 90 degrees) between the x-axis and the major axis of the ellipse that has the same second-moments as the region.” What this means, without getting into too much math, is that the ellipse has the same perimeter and area as the region. With these requisite parameters, the angle can then be calculated so it’s closer to your 2nd guess. If you want to see a paper describing the concepts involved, have a look here.

Regards,
-Mark