Processing and Formatting Effects > Flame FX > Edge Detect >
General Settings

Colour Type box
  Select the colour space that you want to use to isolate the edge.

Result Output box
  Select Result to output the composite of the input image, input matte, and the matte generated by the edge detection. Or, select Edge Only to output only the result of compositing the input image with the matte generated by the edge detection.
Matte Output button
  Select Input to output the input matte or Edge Matte to output the matte generated by the edge detection.