How to do efficient overlay with IDL ?

["Jean Luc MAILLART" <jeanluc.maillart(at)wanadoo.fr>]

Hello

I have a camera connected with some DLL functions writen in C++ that are
called by IDL main program.
The acquired images are processed and displayed with overlays results by IDL
program.
Today i use TV ou TVSCL for display, then i use some PLOT procedure with
specific reserved values in the color table to draw the overlays
informations. after each frame acquisition.
This kind of method is not very efficient under 256 colours, and is
dramaticaly slow under full colors display, and limit the ability to deal
with real-time processing (50 or 60 frames/sec).

Is somebody knows :

1) Why IDL is dramaticaly slower in full colors (3 to 4 time more than in
256 colors !) ?

2) Others more efficient methods to deal with overlays informations on IDL ?

Thank's for your help.

Jean Luc Maillart
France
jeanluc.maillart@wanadoo.fr