What are reds and trans in Image processing I'm trying to understand this code, however I'm unable to deduce the meaning of reds and trans. I would be glad if you can help with it:

import sys
import Image

# pixel constants in hex
trans="\x00\x00\x00\x00"
# reds most to least, the last is trans and used as a noise factor
reds=("\xf1\x34\x00\xff" , "\xfa\x00\x2f\xff",
   "\xf1\x36\x36\xff", "\xfe\x74\x74\xff", "\xfe\xc3\xc3\xff",
   "\xf9\xcb\xcb\xff", "\xf1\xd3\xd3\xff", "\x00\x00\x00\x00")


The complete code is at: https://matsu-project.googlecode.com/svn-history/r28/trunk/streaming-image-processing/src/reduce.py
The numbers appear to be RGBA values: red, green, blue, and alpha (transparency).

reds appear to be mostly red-tinted colors (except the last entry, which is a completely transparent  item).

trans is the transparent "color".