Setting the Color Scale

This procedure shows how to set the color of the time-frequency representation using the Color Scale. The time-frequency representation is a graph in 3 dimensions, also known as a Colormap. The first dimension of this graph is time, the second dimension is frequency and the third dimension is color.

Note: Color, the third dimension can be set by using the Color scale settings. The Color scale associates each amplitude in decibels of a time-frequency representation with a color scale. The amplitudes higher than or equal to the maximum value in dB are displayed in dark red. The amplitudes below or equal to the minimum value in dB are displayed in dark blue.

To Set the Color Scale:

  1. Open or calculate a time frequency representation.
  2. Click View > Colour scale to display the color scale under the time-frequency representation.
  3. Click View > Colour scale settings to display the Colour scale window.
    Figure 1. The Color scale settings dialog.
  4. To define the maximum value in dB:

    • Check Automatic maximum to match the maximum value of the color scale with the highest amplitude in dB that is contained in the signal or,

    • Enter a value in the Maximum to freely set the maximum value in dB.

  5. Enter a value in Dynamic box to modify the difference between the minimum and the maximum value.
  6. If needed, check Custom scale to highlight specific features by customizing the color scale settings.
    1. Click to display the Colour scale adjustment dialog box.
    2. Specify the value for the Minimum level in dB.
    3. Click to change the color for the minimum values in dB.
    4. Repeat the operation for the intermediate and the maximum value in dB.
      Figure 2. The Custom scale principle

The Color Scale is set.