Osprey 800a, User Manual

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Osprey 800e Series User Guide
Osprey by Variosystems 23
Gamma correction controls
The Gamma slider and control adjusts the gamma of the incoming video. Gamma refers to the
response curve of video cameras and CRTs. When video is captured through a camera, the response
of the camera is deliberately nonlinear—low lumen values are boosted, and high lumen values are
compressed. This process is done for two reasons.

It increases the effective bandwidth in the low lumen range, where it is needed, at the expense of the
high lumen range, where it is needed less.

It matches the response characteristics of TV sets and monitors.
The calibration specified in video standards matches the requirements of cameras and television
sets in broadcast use, but generally does not match the needs of computer-based applications or
the response curves of computer monitors. Therefore, a correction inverse to the original bias is
often needed, and you may want to adjust the gamma for the characteristics of a particular monitor.
Note: When gamma correction is disabled, either by setting the Gamma to Neutral or by setting the Gamma correction
value to exactly 100, the software-based Gamma filter works in passthrough mode with no effect on the video and
without using processing bandwidth.
When Gamma correction is enabled, the factor applied is as shown in the slider text box and in the graphic. If you are
running preview video while adjusting the filter, you will see the effects of your adjustments as you make the
adjustments.
The Video Proc Amp tab also has the following controls.
Pin Type The drop-down list has three choices. See Capture and preview pins for
information on how this selection works.
Gamma
correction
controls The slider controls are used to set Gamma, Brightness, Contrast, Hue, and
Saturation. (The Hue slider is disabled when PAL is selected.) All slider values
are applied real time. For example, if Preview or real-time capture-to-screen
video is running when you access the Preview tab, you can see adjustments as
you make changes.
Individual
Restore buttons return the respective slider to the settings as set
when the dialog box is opened. An adjustment scale is also included to identify
each slider’s relative position.
Note: If you change the video standard or video input you will not see any changes in the
slider controls until the driver properties dialog is closed and re-opened.
Reset Values Click this button to reset all slide controls simultaneously to the state they were
in when the dialog box was opened.
Neutral Click this button to reset all slide controls simultaneously to the original factory
default settings. These defaults are considered neutral, that is, the controls are
set to positions that pass through the incoming video without modification.
Start Preview Click to view the gamma settings in real time. You can see adjustments as you
make changes.
Stop Preview Stops the preview.
Vector Scope Click this button to view the vector scope.
Luma Scope Click this button to view the luma scope.