Contours
DS9 can create and display contours as an overlay on an
image. The Display Contours menu
is used to display contours. To create, copy, paste, and
configure
contours, use the Contour Parameters menu.
Contour Parameters
When creating a new contour, a dialog box appears, in which the user
selects the number of contour levels, smoothness, and the distribution
of the contours.
Contour Levels
Specifies the number of contour levels to be generated. A typical
number is between 1 and 10. Note: large numbers of contours can take a
long time to generate.
Contour Smoothness
Specifies how smooth the contours are. A smoothness level of 1 will
evaluate the contour at each image pixel. A level of 2 will evaluate
the contour at every other pixel. The larger the number, the quicker
the contour will be generated, and the less detail will be available.
Contour Scale
Specifies the distribution of the contour levels. A linear distribution
will have equal spacing between contours, Log and Ln will be
weighted at one end. There are two ways to indicate the contour scale,
Use Frame
Scale (automatic) and manual
Use Frame Scale
Use the color scale that the image is currently being displayed in.
Therefor there is a one-to-one match between the image color scale
distribution and the contour levels. Manual
Manually indicate upper and lower levels and a distribution for the
contour levels. The contours generated will not be matched to the image
color scale distribution.
Contour Method
There are two methods that are available to calculate the contour
lines. The first, BLOCK, blocks down the image, by the smoothness
factor, before contours are calculated. As a result, the larger the
smoothness, the faster the result.
The second method, SMOOTH, smoothes the image before calculating
contours. As a result, the larger the smoothness, the slower the
result.