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HueKeyer

This node is a chroma keyer. It calculates hue from the incoming red, green, and blue channels, and uses the amount curve to determine the value to output in the alpha channel. In the graph, the x axis represents hue and the y axis the alpha value for that hue. To key out a particular hue, find the hue on the x axis and Ctrl/Cmd+Alt+click to create a point on the curve at that location. Then drag the point up to a value of 1 on the y axis to set that hue to black in the alpha channel.

Inputs and Controls

Connection Type	Connection Name	Function
Input	unnamed	The image sequence to key.

Control (UI)	Knob (Scripting)	Default Value	Function
HueKeyer Tab
channels	channels	rgb	The hue is calculated from these channels.
lut	lut	N/A	Use the amount curve to control the amount of alpha that is output from the hue. With the sat_thrsh curve you can adjust the saturation threshold. Increase this threshold to reject hues with low saturation.
output	output	enabled	Enables the associated output channel to the right. Disabling this checkbox is the same as setting the channel to none.
		rgba.alpha	Render the resulting image into this output channel.
invert	invert	enabled	Inverts the use of the alpha channel so that the result is a matte.