927 
PIXEL VALUE 
Figure 4 Histogram of the gray levels of the video dimage 
of the fluorescence of soybean residue on the dry Codorus 
soil. The horizontal axis is the 8-bit gray scale value (ie., 0- 
255) and the vertical axis is the number of pixels in each 
gray scale bin. Note the break in the vertical axis is far the 
'O' intensity bin; its pixel count exceedes 210,000. 
Figure 5 Image of the classification results for soybean residue 
on the dry Codorus soil. Pixels with values < 1 were classified as 
soil and the remainder were classified as residue. The percent 
residue cover estimated by analaysis of the fluorescence image 
was 23.2% compared to the measured cover of 22.2%.