Program OVN_bg
! Image of a Gaussian noise A.Bijaoui 15/07/02
! Modified 03/11/09

    Character(Len=80) String,Mouch,Ifs
	Character(Len=60) Comment
    Character(Len=100) Option(50)
    Integer Lu,Nc,Nl,Np,Bp,Status,Ns,Is,Ip,Nseed
    Integer Ikeys,Nkeys,Err
    Real Xd,Yd,Dx,Dy,Ran,X,Y,Pi2,Sigma
	Real, dimension(:), Allocatable :: V

    Call Getline(Nkeys,Option)

	Pi2=8.*Atan(1.)
    Lu=1
	Ifs='bg1.fit'
    Sigma=1.
    Mouch='mouch.lis'
    Nc=1024
    Nl=1024
	Nseed=2002
    Dx=1.
    Dy=1.
    Xd=0.
    Yd=0.
    Bp=-32

    If(Nkeys.eq.0) then
      Write(*,*) 'Syntax : -o Image_noise -c Number_Columns -l Number_Lines'
      Write(*,*) '         -n Seed  -s Noise_sd -m logfile'
      Write(*,*) 'Image of a Gaussian noise'
      Write(*,*) '-o Image_Noise : Image of the Gaussian noise (bg1.fit)'
	  Write(*,*) '-c Number_Columns: number of columns / line (1024)'
	  Write(*,*) '-l Number_Lines: number of lines / line (1024)'
	  Write(*,*) '-n Seed: Seed for the radomizer (2002)'
	  Write(*,*) '-s Noise_sd: standard deviation of the noise (1.)'
      Write(*,*) '-m logfile : name of the log file (mouch.lis)'
	  Stop
    Endif

    Do Ikeys=1,Nkeys,2
      if(Option(Ikeys).eq.'-i')  Ifs    =Option(Ikeys+1) 
      if(Option(Ikeys).eq.'-c')  Read(Option(Ikeys+1),*) Nc 
      if(Option(Ikeys).eq.'-l')  Read(Option(Ikeys+1),*) Nl 
      if(Option(Ikeys).eq.'-n')  Read(Option(Ikeys+1),*) Seed 
      if(Option(Ikeys).eq.'-s')  Read(Option(Ikeys+1),*) Sigma 
      if(Option(Ikeys).eq.'-m')  Mouch  =Option(Ikeys+1)
    Enddo

    Call Debut('OVN_bg',Mouch)

    Call WC('Image of a white Gaussian noise')

    Call WI('Number of Columns',Nc,1)
    Call WI('Number of Lines  ',Nl,1)
	Call WI('Seed             ',Nseed,1)
	Call WR('Sigma            ',Sigma,1)
    Np=Nc*Nl
    Allocate(V(Np),stat=err) ; If(err/=0) Stop "Allocation problem"

    Do Ip=1,Np
	  X=sqrt(-2.*Alog(Ran(Nseed)))*cos(Pi2*Ran(Nseed))
	  V(Ip)=Sigma*X
    Enddo

    CALL WC('Resulting Image  : '//Ifs)
	Comment='Gaussian noise'
    Call CFits(Ifs,Lu,Comment,Nc,Nl,Dx,Dy,Xd,Yd,BP)
    Call FtpprE(Lu,0,1,Np,V,Status)
    Call FTClos(Lu,Status)

    CALL LAFIN('OVN_bg')
    END Program OVN_bg