#!/bin/bash
INPUT="/full/path/hf2.jpg" # or something like that, according to your grabber
WORKPNG1="/tmp/workpng1.png" # temporary file
WORKPNG2="/tmp/workpng2.png" # temporary file
GRABBER="qrsspig"
GCONFIG="config-40m.txt" # the filename of configuration file if multiple grabbers are running
# ^ this filename can be checked by e.g. "ps -ef | grep qrsspig"

LIMIT="50" # the lowest allowed intensity for continuing the grabber

while true ; do # never stop this test
  if [ -f "$INPUT" ] ; then # if the grab does not exist we will not kill the grabber
	rm $WORKPNG1
	rm $WORKPNG2

	# we need to analyze only the spectral part of the picture:
	convert -crop 500x400+100+150 $INPUT $WORKPNG1 # the dimensions and position of the "data" part
	# now you can check if the selection was OK in workpng1.png
	convert   -resize 50x40\! $WORKPNG1 $WORKPNG2 # decrease the size and some noise
 
	# max blue intensity:
	MAX=$( convert $WORKPNG2 txt: | awk -F "(" '{print $2}' | awk -F ")" '{print $1}'| awk -F "," '{print $3}' | sort -n | tail -1 )
	echo -n "max:$MAX "
	# blue shoud work for most of the grabbers. But you can select RED by "print $1" or GREEN by "print $2"

	if [ "$MAX" -lt "$LIMIT"  ] ; then
		echo "Killing the grabber!"
		for PID in $( ps -ef | grep -v grep | grep "$GRABBER" | grep "$GCONFIG" | awk '{ print $2 }' ) ; do kill $PID ; done
	else
		echo "OK"
	fi
  else
	echo "No grab available..."
  fi
	sleep 20s # 600s ??
done