function pow1d,inima
; 
; Calculation of the 1-D power spectrum of an 1-D array 
; Usage: Result = pow1d(array) 
 
   siz=size(inima) 
   if siz(0) ne 1 then goto,wrong 
   n=siz(1) 
   ima=inima 
 
; apodization 
 
   mea=mean(ima) 
   ima=ima-mea 
 
   perc=5.               ; percentage of frame size to be damped 
   np=nint(n*perc/100.) 
   u=fltarr(n)+1. 
   u(0)=0. 
   for i=1,np do u(i)=(1.-cos(!pi*i/np))/2. 
   u(n-np:n-1)=reverse(u(1:np)) 
 
   ima=ima*u          ; apodized frame (mean subtracted) 
 
; Fourier transform 
 
   fo=fft(ima,-1) 
   rfo=float(fo) 
   ifo=imaginary(fo) 
 
; Power spectrum = Re(fo)^2 + Im(fo)^2 
 
   ps=rfo*rfo+ifo*ifo 
   goto,fin 
 
wrong: 
   print,'ERROR: The array must be one-dimensional' 
   ps=0 
 
fin: 
   return,ps 
   end