3—Basic Operation of the Tau 640 and GUI
Tau 640 User’s Manual
3-24
June 2011
TAU-0640-00-10, version 110
Linear Histogram
: Image contrast and brightness (gain and level) optimized
automatically based upon scene statistics using a linear transfer function. Controls for
the
ITT Mean
(sets grey scale midpoint) and
Max Gain
(AGC gain) are adjustable by
entering the value in the
Automatic Parameters
section. The Linear Histogram
algorithm uses scene statistics to set a global gain and offset (contrast and
brightness) for the image. Upon entry into the linear histogram mode, the currently-
stored values are applied (i.e. the power-on defaults or the last saved values).
Note
Linear Parameters:
Used for fine tuning the
Auto Bright
,
Once
Bright
, and
Manual
modes, these settings are contextually active
depending on which
Algorithm
is selected. Each of their settings is
described above.
Once Bright
– Only the
Contrast
control is active.
Auto Bright
– The
Brightness Bias
and
Contrast
controls
are active.
Manual
– The
Brightness
and
Contrast
controls are active.
Automatic Parameters:
Used for fine tuning the
Automatic
and
Linear Histogram
modes, these settings are
contextually active depending on which AGC algorithm is
selected. Each of their settings is described above as they
pertain to the particular
Algorithm
.
Automatic
– The
Plateau Value, ITT Mean,
and
Max
Gain
controls are active.
Manual
– The
ITT Mean
and
Max Gain
controls are
active.
In
Manual mode
and
Once Bright
mode, the brightness setting must be updated as the
camera temperature changes. To avoid this issue, it is recommended to use
Automatic
or
Auto Bright
right modes when possible. Also, AGC mode will only affect the digital data output
if the Digital Video output mode is set to 8-bit data. The 14-bit digital data bypasses the AGC
sections of digital processing.
