vtkFlyingEdges2D generates scaled contours

Hi all,
I’m implementing vtkFlyingEdges2D to a CT image to generate a contour of the bone. But the output of vtkFlyingEdges2D has been scaled to a level of 1.2x.

I post the result below.

bounds of contour >> 69.9951 69.9951 79.7139 253.098 0 1238.49
bounds of ct image >> 81.6406 81.6406 0 417.184 0 1061.83

If you know how to solve this problem, please let me know.

If I set the sliceOrientaionToXY, the contour scale is fine.

But the others slice orientation will generate different scale contours like before.

This is probably because the image is unisotropic. I think you’ll need to apply a matrix an somekind of scaling factor.
I’d read about how Slicer does this for threshold segment editor effect if I were you

Hope it helps

Thank you for your suggestion,I’ll try this later.