REMOVE-LINEAR-BASELINE

Fit and remove a linear baseline from the current spectrum. The routine fits a linear gradient between the average levels in two ``baseline regions'', which may be defined either interactively (if INTERACTIVE mode is set and the plot device is a terminal) or manually otherwise (as in the example below).

This is the only baseline fitting command that actually goes ahead and removes the baseline from the spectrum. If you want to retain the baseline for other purposes you can PUSH the stack before removing the slope, and then subtract the residuals from the original spectrum. Alternatively you can use FIT-POLYNOMIAL-BASELINE or FIT-COMPOSITE-BASELINE.

Note: Only 2 baseline pairs are used for this command. These are not the same point-pairs that are used for FIT-POLY-BASELINE etc.and FIND-SPECTRUM-STATISTICS etc..

Relevant flags:

RLB_INTS(4)

I4

Channels (start,end) defining two regions to be used for baseline removal.

Examples:

    >> remove-linear-baseline <CR>
    Type intervals, one at a time, CTRL(Z) to finish
    Current units are km/s  

    # -20 -10 <CR>
    # 10 20 <CR>
    ..