300
 Threshold
 a Citrus x Leaf Background

 250 ........anx. a. ~~r cLC4 oe e oemouse B omo 0..o

 X D x "xx x 0
a 200 x x oo x
 o x x o o a
 150" xy x a o oo
 I 0~ ~ o a no 00

 10 .ox o oo ox
 o x n o oxxo 0
 05 .% o o fi 0"
 50" o x oo






 3 00 o qp o


 250







 150



T 100
-1


 50


 0 50 100 150 200 250 300

 Hue (gray level)

Figure 4-8. Pixel distribution in 25 calibration images in hue-luminance plane.