# [Possible bug] skeptical result of `plot_angular_power_spectrum` method.

[taki-climb]

background

I frequently use this library on my research activity.
During using of above method(and private method _get_angular_power_spectrum), I noticed spectrum amplitude of specific angle around 0, 60 , 118° seems to have significant peak in many surfaces of my own measurement data.
So, I tried to find out whether this behavior occurs general case or not as first step and then I loaded exaple data of this library surfalize.examples and tested whether each surface's result of above method have simillar tendency or not.
The result was below and I still have same question that some specific angle like around 118, 60-degree.

file name	image
test_1.tmd
test_2.opd
test_1.x3p

To be honest, because I'm not familiar with signal processing much, I don't have much confidence whether this result was correct or not. But I'm still struggling to find out this reason/solution.

request

• Identify the issue is related to a library or method.
• If above result is yes(related or this library/method's unique problem), please tell me the solution or cooperate explore the cause of this issue.

source

attachment file verification.ipynb is evidence(?) and simple example of above behavior.

Sorry for my poor English.
Regards.

verification.zip

[fredericjs]

Hi and sorry for the late reply. I'm also not entirely sure this method is flawless. Maybe I should flag it as experimental. In anyway, I'm sorry to say I don't have much time to work on this right now. If you come up with a solution, I'm happy to look at a pull request though.

[taki-climb]

Hi @fredericjs , Thanks for replying this issue post.
I worried about I may have made this project suspended.
I'll continue to try to find out whether this method's behavior is correct or not.
If I fixed this method after I confirmed this method have some problem, I'll send pull request.
I will add updates to this issue as progress is made.

[fredericjs]

Don't worry. I'm simply focusing on finishing my PhD right now and have other things taking up my time, that's why I don't have much time to work on this library at the moment. Doesn't mean I will abandon it :)