Radial Average Spectrum

Use the FFT2RSPC GX to calculate the radially averaged power spectrum of an FFT2 Transform image.

Name of Input Transform (grid) File

Select the name of the input transform file.

Script Parameter: FFT2.TRN

Name of Output Spectrum File

Specify the name of the output radially averaged power. spectrum file

Script Parameter: FFT2.SPC

NX= original X dimension

NY= original Y dimension

DX= X element separation

DY= Y element separation

WX= 1/(NX*DX), wavenumber increment in X

WY= 1/(NY*DY), wavenumber increment in Y

QX= 1/(2*DX) , Nyquist in X

QY= 1/(2*DY) , Nyquist in Y

0 +WX +QX

r i r i r i

v NY-1 . . . . . . . . . . -WY

e . . . . . . . . . . -WY*2

c . . . . . . . . . .

t . . . . . . . . . .

o . . . . . . . . . .

r . . . . . . . . . .

. . . . . . . . . . -(QY-WY)

^ . . . . . . . . . . QY

| . . . . . . . . . . QY-WY

. . . . . . . . . .

2 . . . . . . . . . . WY*2

1 . . . . . . . . . . WY

0 . . . . . . . . . . 0

0 1 2 (NX+1) -> element

(The X(-)Y(+) portion will be complex conjugate of the X(+)Y(-) portion)

(The X(-)Y(-) portion will be complex conjugate of the X(+)Y(+) portion)