.help window Jan86 images.tv.iis
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NAME
window -- adjust the contrast and dc offset of the current frame
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USAGE
window
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DESCRIPTION
The lookup table between the display frame values and the values sent
to the display monitor is adjusted interactively to enhance the display.
The mapping is linear with two adjustable parameters; the intercept
and the slope.  The two values are set with the image display cursor
in the two dimensional plane of the display.  The horizontal position
of the cursor sets the intercept or zero point of the transformation.
Moving the cursor to the left lowers the zero point while moving the cursor to
the right increases the zero point.  The vertical position of the cursor
sets the slope of the transformation.  The middle of the display is zero
slope (all frame values map into the same output value) while points above
the middle have negative slope and points below the middle have positive
slope.  Positions near the middle have low contrast while positions near
the top and bottom have very high contrast.  By changing the slope from
positive to negative the image may be displayed as positive or negative.

The interactive loop is exited by pressing any button on the cursor control.
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EXAMPLES
.nf
	cl> window
	Window the display and push any button to exit:
.fi
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BUGS
It may be necessary to execute FRAME before windowing.
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SEE ALSO
cv
.endhelp
