5.3 Graphics Plane Mask

The mask function allows the user to create a graphics mask of specified intensity values for the single band displayed image. The user is allowed to create up to four individual masks. Each mask may have its own unique color which is selected from the eight predefined colors in the mask color box.
Mask Color:
The color box shows the user the eight predefined colors available for the graphics masks. The user selects a color by pressing the left mouse button on the desired color. The selected color will be outlined in gold to indicate that it has been selected.

Values:
This text field allows the user to enter the range of image values and/or the specific image values for which the mask is to be created. Range values should be separated by a dash (-) and individual image values should be separated by either a space or a comma (,). The following conditions cause an error message to be displayed:

  1. The first character in the input specification is not numeric.
  2. Any alphabetic characters appear in the specification.
  3. Any punctuation marks other than a dash (-) or a comma (,) are used.
  4. Two consecutive punctuation marks appear in the specification.
  5. Both ends of a range are not specified (i.e. "10 - " or "- 100").
  6. A value less than 0 or greater than 255 is specified.

Rotator Icon:
The rotator icon allows the user to select the current graphics mask to be generated or cleared. Clicking the left mouse button on the icon increments the current graphics mask number by one. The graphics mask number continues to be incremented until the maximum graphics mask number is reached (four), at which point the current graphics mask number returns to one.

Apply:
Generate and display the graphics mask based on the image values specified by the user. Validation of the range and bin specification is done at this time. If an error is detected in the specification, the mask is not generated.

Clear:
Erase the current graphics mask. Since clearing the graphics mask involves regenerating the image, there will be a delay before the image is redisplayed after the clear button is selected.

Dismiss:
Close the graphics mask panel.

Note: Initializing the graphics planes from the Initialize panel does not clear graphics masks. Use the clear button on the graphics plane mask panel to erase any graphics masks no longer needed.