Sony DVS-7300 User Manual page 290

Enhanced Chroma Keying (Single Mode)
Adjusting the chroma key shadow
This function provides a more realistic treatment when the shadow of an
object in the field of view falls on the blue background. Since parts of the
blue background darker than a specified intensity are treated as shadows,
there is no effect on cutting out of the foreground.
Use the following procedure.
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2
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Chapter 5 Chroma Keying
In the ADJUST menu, press F9 (SHADOW), turning it on.
This turns the chroma key shadow function on.
Adjust the parameters.
Knob Parameter
1 Luminance
2 Gain
3 Density
4 Softness
Setting
Set luminance (0.00 to 100.00)
Set the shadow key gain (0.00 to 100.00)
Set shadow density (0.00 to 100.00)
Set the degree of shadow blurring (0.00 to 100.00)