Spectral Calibration Format

The calibration parameters of the spectral calibration tool are stored on disk files (using the default file extension '.ilsc') according to the following format:

The calibration file is an ASCII text file and contains a header line followed by four data parts. The header line is a unique string which identifies the file as an Epina ImageLab calibration file. The data parts are indicated by specific keywords which begin with a backslash character:

  • \Vers: the version number of the format
  • \Data: the full file specification of the data file which has been used to create the calibration data
  • \NGrps: the number of the spectral groups
  • \CaldD: for each spectral group the keyline \CaldD contains the group number, the number of pivot points and the order of the calibration polynomial. This line is followed by the specified number of pivot points, each specifying the layer index and the wavelength.

Following is an example containing the calibration data of two spectral groups. The first calibrated by a parabolic function using 8 pivot points, the second group is calibrated linearly with four pivot points:

     \Vers 1
     \Data D:\imagelab_data\Ausmale\Ausmale1_coffee_pos.ilab
     \NGrps 1
     \CalD 1 8 2
     1048   155.598
     1056   156.614
     1158   170.865
     1341   196.223
     1450   211.446
     1632   236.748
     2075   298.262
     2191   314.380
     \CalD 2 4 1
     106   126.614
     118   138.865
     140   160.446
     275   295.262