A baseline fitting utility for spectral data. Adds some items to the macros, marquee and trace popup menus. Use the all traces (shift-click) popup menu to fit baselines to many traces at once. To use the utility, make a plot of your raw data, initialise the baseline fit, select areas of the data with a marquee and right click for the option to add those regions to a maskwave. You can fit a line, 3rd or 4th order polynomial, Gaussian, Lorentzian or exponential curve or a smoothed spline to the selected regions and subtract the baseline via macro, trace or marquee menus.

The procedure is similar in operation to the baseline fitting part of the procedure from Wavemetrics Technical Note #020 Peak Measurement and Fitting. Additional features include:

1. Use of the trace and marquee popup menus and the marquee for efficient
   input
2. A menu driven option to fit many traces at once
3. Transparent command line operations to enable automation of fitting
4. Smoothed spline baseline

Usage

The baseline fitting routines require that the spectra to be fit are plotted in the top graph window. Select Baselines -> Initialise Baseline Fit... to choose the raw spectrum from which the baseline is to be removed. Baselines -> Add Region to Fit and Baselines -> Delete Region from Fit add or delete the marquee selected region to the mask wave. Clear All Regions clears the mask wave. Use the Fit submenu to select the fit type. If you choose a spline fit, a control will appear on the graph, allowing you to adjust the smoothness parameter until you're satisfied with the fit. A residual (baseline-subtracted) wave is shown on the plot whenever you fit a baseline, but is overwritten for every fit. Use Baselines -> subtract baseline to make a new baseline-subtracted wave. The baseline is also saved when you create the baseline subtracted wave. Use the all traces (shift-click) popup menu to fit baselines to many traces at once. When fitting many traces the baseline will be automatically subtracted from each plotted spectrum.

For a more freeform baseline fitting method, see my baseline spline fit package.

Releases