I don't know much about motion detection, but your code calls for some remarks:
- color(#ABCDEF) is a redundant call. You can use #ABCDEF directly.
- There is a syntax for easy array initialization, removing the need to write all the indexes...
Instead of color[] c = new color[36]; then initializing each slot in setup(), try:
color[] c =
{  
  #f4b264,
  #bee5e4,
  #fe022b,
  #082f56,
  #f8f3d6,
  #fceea7,
  #ff7101,
  #f1d7ca,
  #ffafc3,
  #abe6e2,
  #e2e8ce,
  #ffcb00,
  #aae354,
  #ddb0b7,
  #d2e6b5,
  #77a3be,
  #005c9d,
  #bb3325,
  #fdd4e2,
  #0dbbde,
  #643324,
  #99e1d3,
  #ff92a9,
  #a7bbba,
  #d0e099,
  #00b14b,
  #0376b9,
  #fedf2d,
  #fbd362,
  #fe5900,
  #4fb900,
  #fdd4e2,
  #ddb0b7,
  #a9998a,
  #77a3be,
  #bdb0b7,
};
Same size, but easier to type (here I just used a regular expression in my editor to isolate the relevant parts) and to read. And faster, even if it is unimportant here.

Thanks PhiLho that is a lot easier and more efficient, wish I knew this before I wrote all the indexes .