Frequency-Time Image Display

   

The command VIEW/POWER_IMAGE takes in input the rough -T image produced by the command MAKE/POWER_SPECTRUM S and plots it in a 3-dimensional view after (or not) conversion to rms units. It is possible to specify a constant value to be subtracted to the power, to select azimuth and altitude for the viewing angle, to smooth the image (with the same factor in time and frequency), to draw lines in X, Y and XY direction and to select a lin/log scale for the Z-axis. The plot will be directed to the default plot device. The syntax of the command is:

VIEW/POWER_IMAGE ima [wn] [azi] [alt] [smo] [xyf] [logf] [rmsf]

where:

• ima is the input image (in rough format as produced by the
  MAKE/POWER_SPECTRUM S command.
• wn is the value for the white noise to be subtracted. Default is 2.0.
• azi is the azimuth for the viewing angle, according to the MIDAS manual for the command PLOT/PERSPECTIVE. Default value is -45.
• alt is the altitude for the viewing angle, according to the MIDAS manual for the command PLOT/PERSPECTIVE. Default value is 30.
• smo is the smoothing factor. Defaulted to 1 (no smoothing).
• xyf is the flag to indicate which lines should be drawn in the plot. X for lines along the x-axis only, Y for lines along the y-axis only, and XY (default) for lines in both directions.
• logf is the flag for logarithmic transformation of the image. 1 for logarithmic image, 0 (default) for linear image.
• rmsf is the flag for rms transformation:

  RMS

  transformation enabled

  NO

  (default) no transformation