about the calculation of phase spectrum for a set of coordinates

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ZhG
ZhG 2013년 9월 19일
I want to implement an approach for calculating Phase spectrum of a set of coordinates. In the paper, it is described as 3 equations. However, I have no idea about the function variables (x,y) in the equation. I want to implement it via Matlab. Perhaps, it is easier for someone who knows pure signal processing well.
In (1), the 2D signal series (the coordinates) is represented as a 2D dirac delta function. Varialbe, theta_i, is the direction of each coordinate. The fourier transform of (1) is in the form of (2). Then (3) is the phase spectrum. So, maybe it can be implemented via a few lines in Matlab. But I just don't know it. Could anyone here give any help? Thanks.

답변 (1개)

Honglei Chen
Honglei Chen 2013년 9월 20일
This looks to me is essentially
angle(fft2(theta))
where
theta is the function exp(j\theta_i) defined at each (xi,yi) position
Of course, it depends on how xi, yi, u, and v are defined.
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ZhG
ZhG 2013년 9월 21일
Honglei, thanks for reply.
I searched with google and know that angle() is to calculate phase. And I found that this function involves in something about 'unwrapping', introduced in some posts. I don't understand that, but this is not my problem. I am wondering that how I can understand variables (x,y) of eq.(1). Because (xi, yi, theta_i) are given values, i.e. each point in the coordinate system and its direction.
Honglei Chen
Honglei Chen 2013년 9월 23일
I don't really understand what you are asking for, could you provide an example? In general, the coordinate itself doesn't really matter, as long as the system is shift invariant.

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