Gemini Software Operation
Gemini 720is Imaging Sonar
Document: 0703-SOM-00002, Issue: 7
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© Tritech International Ltd.
5.1.17. Gain Control
The Gain slider at the bottom left hand side of the display is used to change the gain level
being used by the Gemini head, and is expressed as a percentage between 0 (no gain being
applied) and 100 (full gain being applied).
The gain can be changed by either clicking on the dark blue indicator showing the current gain
position in the slider and dragging it left or right, or by using the arrows at the end to change
the gain one step at a time. The arrows are designed for fine control of the gain and operate
one step per click and clicking on the arrows and holding them down will have no effect.
The gain can also be altered using keyboard shortcuts ('z' to decrease gain, 'a' to increase
gain).
5.1.18. Range Control
The Range slider at the bottom left hand side of the display is used to change to the range
of the image being acquired by the Gemini head.
The range can be changed by either clicking on the dark blue indicator showing the current
range position in the slider and dragging it left or right, or by using the arrows at the end to
change the range one step at a time. The arrows are designed for fine control of the range
and operate one step per click and clicking on the arrows and holding them down will have no
effect. The range control has been implemented with a logarithmic scale so that the smaller
values of range can be more precisely selected.
The range can also be altered using keyboard shortcuts ('c' to decrease range, 'd' to increase
range).
5.1.19. Indicators
When the mouse pointer is within the ‘cone’ on the sonar display (that is over the displayed
sonar image), the indicators at the bottom right hand side of the screen will show the position
of the mouse pointer relative to the origin of the display (that is relative to the Gemini Sonar).
The pointer position is expressed as a range / bearing pair, and as a Cartesian co-ordinate
(X, Y).
5.1.20. Sonar Swathe
Around the edge of the sonar cone there are three handles that allow the swathe size (also
known as the aperture size) to be adjusted.
Click and hold the mouse over one of the handles. The clicked handle, and any other handles
that will move when the mouse is dragged, will be highlighted. Square shaped handles adjust
the edges of the swathe size. Diamond shaped handles adjust the centre of the swathe size.
