negative numbered CLI args cannot be parsed properly

[LBlend]

since - is a reserved character for specifying args, the program cannot parse the threshold CLI arg properly when given a negative number

The way to mitigate this issue is to use the --argname=argvalue syntax, i.e --threshold=-75

There should be an instruction telling you to use this syntax or be implemented a solution that parses it properly when used in this manner --threshold -75