First of all, thank you very much for the response.
In regards to answering exactly what I would like to get from the plugin that would represent (surface reghneess).
While reading through the plugin’s explanation on ImageJ page I found that there are two main results, among others, that would probably reflect what roughness is.
1-Dispersion (º): which reports the standered deviation of the indicated directions.
2-Goodness: reports the goodness of the fit; 1 is good, 0 is bad
Since the plugin looks to indicate the amount of structures in a given direction, represented in a result Histogram, where Images with completely isotropic content are expected to give a flat histogram, whereas images in which there is a preferred orientation are expected to give a histogram with a peak at that orientation
Meaning a sample like that I have posted, which has many angles that represent changes in direction. So what I have done to see (what would be considered isotropic) is it a flat line? Or an unangulated (smooth) line. Is the proplem with curveture or angulations.
So I drew a line representing how would the picture posted be if it has no angles just so smooth.
And the results was good it appears that the Dispersion and goodness react to the smoothness of the line regardless of its shape either flat or curved.
With all of that being said, I still do not exactly understand how the plugin gets the oriantation what makes a negative or positive degree. What are the differences between the two main choices the plugin provides
Local gradient orientation. And
Fourier components analysis
I am so sorry for the very long response. And hope it makes sense.