Reject dim spectra if the average brightness is less than 5% of the median brightness of all the fibers

[kaashmonee]

Some fibers are much weaker/darker than others and these fibers don't contain useful information so they should be ignored. If the average spectrum brightness is less than 5% of the median spectrum brightness across the entire CCD, then it should be rejected.

• Determine why those dim spectra result in in accurate overlap detection.
• Remove the spectra with inaccurate boundary detection.