Discrimination; Smartfind - Minelab E-Trac Instruction Manual

Discrimination

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Discrimination is the detector's ability to
eliminate signals from undesired targets and
accept signals from desired targets. E-Trac's
advanced signal processing rates detected
objects according to their conductivity and
ferrous characteristics. This enables you to
accept some types of targets and reject
others; the combination of these accepted
and rejected targets form a Smartfind
Discrimination Pattern.
Therefore, each coordinate of the Smartfind
Discrimination Pattern (visible in the Pattern,
Edit and QuickMask Screens) can be turned
white (clear) to accept, or black to reject,
certain targets. White areas of the Smartfind
Discrimination Pattern indicate particular
target coordinates that are accepted, black
areas indicate coordinates that are rejected.
The Pattern shown above is E-Trac's Factory
Preset Coins Mode Discrimination Pattern,
which represents the typical characteristics
of nonferrous coins; a composite of hundreds
of coins from around the world. It accepts
signals from nonferrous targets and rejects
signals from most ferrous targets.
When an accepted target is detected (e.g.
matching the conductive and ferrous
characteristics of coins), the Target Crosshair
will appear in the white area and a target
response will be heard.
When a rejected target is detected (e.g.
not matching the conductive and ferrous
characteristics of coins), the Threshold will
blank and the Target Crosshair will remain in
the position of the last accepted target.
E-Trac offers a range of Smartfind
Discrimination Patterns (p. 42) which may be
used on their own or in combination.

Smartfind™

Smartfind is Minelab's unique two
dimensional scale of discrimination. Smartfind
graphically represents both the FE-CO target
properties on the same display.
The horizontal axis rates the target on its size/
conductivity (CO), ranging 1–50 from left to
right. The vertical axis rates the extent of the
target's ferrous characteristics (FE), ranging
1–35 from top to bottom.
A FE value of 1 represents low ferrous
characteristics and a value of 35 represents
high ferrous characteristics. Similarly, a CO
value of 1 represents low conductivity and 50
represents high conductivity.
Conductivity
1 50
As the coil passes over a target, the detector
digitally processes the target signals and
displays a Target Crosshair in the Smartfind
Window at the end of detection. The position
of the Target Crosshair is relative to the
target's conductive and ferrous properties.
Ferrous targets (e.g. nails) contain a large
amount of iron, or some other less common
magnetic material. Because they are
magnetic, ferrous targets generally display
the Target Crosshair at the bottom of the
Smartfind Window.
Nonferrous targets (e.g. pure gold, silver,
copper and bronze) contain little or no
magnetic material. Because they are not
magnetic, nonferrous targets will generally
display the crosshair at the top of the
Smartfind Window.
Note: Even nonferrous targets will generate FE
values higher than 1.
High conductive targets (e.g. large silver
coins, copper items) will cause the Target
Crosshair to appear toward the right of the
Smartfind Window.
Low conductive targets (e.g. small alloy coins,
foil, 9ct and fine jewellery) will cause the
Target Crosshair to appear toward the left of
the Smartfind Window.
The object size will have some effect upon
the conductivity rating for targets. Generally,
the larger the target, the higher the
corresponding conductivity rating.
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