PerceptibleImageChannel 1803 Magick++/lib/Image.cpp   PerceptibleImageChannel( image(), channel_, epsilon_ );
PerceptibleImageChannel 1707 magick/threshold.c   status=PerceptibleImageChannel(image,DefaultChannels,epsilon);
PerceptibleImageChannel   51 magick/threshold.h   PerceptibleImageChannel(Image *,const ChannelType,const double),
PerceptibleImageChannel 2276 wand/mogrify.c             (void) PerceptibleImageChannel(*image,channel,StringToDouble(