Crystal Vision
Using Safire 3
If
Multiply Foreground
is selected, the FG signal is keyed before adding to the
keyed BG. Normally this is left de-selected but can be used if it otherwise proves
impossible to create a realistic effect. In this mode,
Suppress Foreground
’ can
still be selected to suppress any colour tinting on foreground objects.
Selecting ‘Suppress Foreground’ and de-selecting ‘Multiply Foreground’
helps retain fine foreground detail and generally gives the most realistic
results with a well-lit backdrop.
Safire 3 is capable of producing a very realistic composite chroma key image, but
to get the best results, attention must be paid to the lighting and quality of the
coloured backdrop, the lighting of the foreground objects and colour and
reflectivity of foreground objects. If all of the above have been considered, then
the Auto Setup feature of Safire 3 will give excellent results.
Auto Setup
For most well lit scenes,
Auto Setup
provides an acceptable chroma keyed
result. Not all of Safire 3’s controls are adjusted automatically so some
knowledge of the other controls is essential. Each control is explained in detail in
the ‘Controls’ section but the following brief explanation with pictorial examples
will help aid understanding.
Auto Setup works by using up to 12 samples from the backdrop area and up to
four samples of the foreground to automatically adjust most of Safire 3’s settings
to achieve the best result by taking into account variations in illumination and
saturation. Auto Setup allows the number and position of samples to be adjusted
and it also offers the option of freezing the FG input video to make positioning the
samples easier.
In the above example, the 12 grab samples can be seen distributed around the
model. With perfect lighting, only one sample might be necessary. In this example
no foreground samples were used and the
Auto Lighting
and
Auto Re-Spill
options were selected. Auto Lighting compensates for variations in lighting
intensity across the backdrop, and Auto Re-Spill replaces any backdrop colour
that may be reflected onto foreground objects with another more realistic colour
derived from the BG signal.
Safire 3 User Manual R1.3
52
24 March 2017
