





SPECPR Users' Manual                                                   Page 8-f9.1


_F_9:  _B_a_n_d _R_e_m_o_v_a_l (_R_e_f_l_e_c_t_i_o_n _M_e_t_h_o_d)                     _A_l_i_a_s: _b_a_n_d[_r_e_m]

     This absorption band removal routine takes one half  of  an  absorption
band and reflects it about the band minimum then, divides a given reflection
spectrum by the calculated band.

     The routine will request:

"Type in the file id and file # to be processed, e to include  errors,  fol-
lowed  by l or r for left- or right-side of band to be reflected.  type e or
x to exit."

     The "l" or "r" refers to left- or right-side of the band  minimum  when
the  spectrum  is  stored  in  increasing wavelength from left to right.  It
refers to the side of the band that you want to be reflected  to  the  other
side.

     Next you will be instructed to:

"enter outer limits of band (2 values), estimated half height point on  side
to   be  reflected  followed  by  h,  a,  n  (channel,  wavelength,  inverse
wavelength), and wavelength file id and number. type e or x to exit."

     The two outer limits are on either side of the band minimum.  The first
limit  tells where to stop the reflection process, the second tells where to
stop looking for the band minimum.  The program types "WORKING" and is doing
the following:

o+ correlating the given band limits to  channels  in  the  wavelength  file,
  default is that the limits are given in terms of channels.

o+ searching for the band minimum by looking for a datum that is smaller than
  the  three  values  on  either  side  of it, between the limits of the 1/2
  height and the second outer band limit.

o+ puts values of one side of band into the position  symmetrically  opposite
  to it relative to the band minimum.

o+ divides spectrum by reflected band.

o+ scales the errors by a factor of (the residual / the original spectrum).

o+ calculates title and history.


     _W_A_R_N_I_N_G: This is a primitive means of removing a band.  It was used  in
the 1970's but does not take into account the nonlinear nature of reflection
spectra.  The results for reflectance spectroscopy are not quantitative.

Original author: Lucy Mcfadden




