Asked by ZhG
on 19 Sep 2013

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.

Answer by Honglei Chen
on 20 Sep 2013

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.

ZhG
on 21 Sep 2013

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
on 23 Sep 2013

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