! A.Bijaoui 2007 November 17th
! Pixel values transform into log
! Modified 03/11/09

    Implicit None

    Real Sigma,Fond
    Character(Len=80) Imagein,Imagelog,Mouch,String
    Character(Len=60) Comment
    Character(Len=100) paramoption(50)
    Integer Status,BP,Nc,Nl,Np,Ip,err,i,nkeys
    Real, allocatable :: T(:)
    Integer Nodef
    Real Xd,Yd,Dx,Dy
      

    Imagelog="dummy"
    ImageIn="dummy"
    mouch='mouch.lis'
	Sigma=1.
    Fond=0.
    call getline(nkeys,paramoption)

    if (nkeys.eq.0) then
      Write(*,*) 'Syntax : -i Image -b Background -s Sigma -o Image_log -l logfile'
      Write(*,*) 'Logarithm conversion taking into account background and deviation'
      Write(*,*) '-i Input Image (required)'
      Write(*,*) '-b Background: bacckground to be subtracted (0.)'
      Write(*,*) '-s Sigma : standard noise deviation (1.)'
      Write(*,*) '-o Image_log : name of the converted image (required)'
      Write(*,*) '-l logfile : name of the log file (def. mouch.lis)'
      Stop
     endif
       
     do i=1,Nkeys,2
       if(paramoption(i).eq.'-i') Imagein    =paramoption(i+1) 
       if(paramoption(i).eq.'-b') Read(paramoption(i+1),*) Fond
       if(paramoption(i).eq.'-s') Read(paramoption(i+1),*) Sigma
       if(paramoption(i).eq.'-o') Imagelog   =paramoption(i+1)
       if(paramoption(i).eq.'-l') Mouch      =paramoption(i+1)
    enddo
    
    If(Imagein.eq."dummy")    Stop "No name for input image"
    If(Imagelog.eq."dummy")   Stop "No name for resulting image"
      
    Call Debut('OVN_tlog',Mouch)

    Call WC('Logarithm conversion taking into account background and deviation')

    Call WC('Input Image '//Imagein)

   	Call OFits(21,ImageIn,Bp,String,Nc,Nl,Dx,Dy,Xd,Yd)
    If(BP.ne.-32) Stop 'This program processes only real data'
	Np=Nc*Nl
    Allocate(T(Np),stat=err) ; If(err/=0) Stop "Allocation problem"
	Status=0
    Call FTGPVE(21,0,1,Np,0,T,Nodef,Status)
    Call FtClos(21,Status)

    Call WR('Background     ',Fond,1)
    Call WR('Noise sigma    ',Sigma,1)

    T=T-Fond

	Do Ip=1,Np
	  If(T(Ip) >= 0.) Then
        T(Ip)=Alog10(1.+T(Ip)/Sigma)
	  Else
        T(Ip)=-Alog10(1.-T(Ip)/Sigma)
	  Endif
	Enddo

	Call WC('Resulting Image: '//Imagelog)
	Comment='Image converted into log values'
    Call CFits(Imagelog,21,Comment,Nc,Nl,Dx,Dy,Xd,Yd,BP)
    Call FtpprE(21,0,1,Np,T,Status)
    Call FTClos(21,Status)

    Call Lafin('OVN_tlog')
	End