Gemini Software Operation
Gemini 720is Imaging Sonar
Document: 0703-SOM-00002, Issue: 1
41
© Tritech International Ltd.
5.2.4. Filter Settings
The
Filter Selector
on the
User
screen selects one of three filters to be applied to the
image before it is displayed. The Filter Setting section of the Configuration Options screen
allows the settings of these three filters to be changed. The
Filter Settings
panel provide
three different data filters that may be applied to the sonar image before it is displayed. The
filters are only active if enabled in the sonar view (See Section 5.1.11, “Filter Selector”).
The
Averaging
filter applies an average over a number of images received from the sonar.
It has the effect of removing random noise and rapidly moving targets from the image.
The
Persistence
filter retains decreasing amounts of earlier images as well as the current
image. It has the effect of highlighting movement in the images, which appears as a decaying
“snail trail” behind the moving object.
The
Movement
filter highlights the changes between images and filters out static returns.
The Movement control sets how much background (i.e. non-moving data) is removed from
the image. With the Movement control set at maximum, the movement filter removes all of
the background and so the display only shows targets that are moving between images. With
the Movement control set at minimum, the movement filter retains almost all the background
(and becomes almost indistinguishable from the
Persistence
filter).