[Gwyddion-users] Surface Roughness measurement from FESEM image?

[Ankush Nandi]

Hello,
I have .tif image of FESEM of a coated carbon fiber and measured the
roughness using the ' ISO calculate roughness parameters' tab in
Gwyddion.Will be this roughness value similar to an AFM image of the same
area of the same coated carbon fiber?

[David Nečas (Yeti)]

Post by Ankush Nandi
I have .tif image of FESEM of a coated carbon fiber and measured the
roughness using the ' ISO calculate roughness parameters' tab in
Gwyddion.Will be this roughness value similar to an AFM image of the same
area of the same coated carbon fiber?

Asking the same twice without bothering to understand the first answer
will not help you progress anywhere.

No, they will not be similar at all.

The first will give you unitless, worthless and essentially arbitrary
numbers. SEM image is a picture, not a height field/height map.
Furthermore, unless (a) the image format is recognised and imported
automatically or (b) you manually set correctly the physical scale in
the import dialogue

http://gwyddion.net/documentation/user-guide-en/specific-data-import.html

even lateral measurements will be wrong.

The second will give you the roughness in physical units, if used
correctly. Generally, you should use 2D statistical characteristics

http://gwyddion.net/documentation/user-guide-en/statistical-analysis.html

if you measure roughness in a 2D area, not 1D.

Yeti