Images captured are cropped for getting the leaf blade area as a part for processing. R,G, B planes are separated along with HSV planes and compared with different combinations of functions obtained from these planes. The different functions used for analysis are as shown in table1. The index that has been already proposed Ik[7] is also considered for comparison. Image I is given by
I= f (R,G,B) (1)
Parameters obtained by image processing are used to correlate with the nitrogen values obtained from laboratory. Linear and non linear regression analyses are applied to obtain optimized regression equation. The results are as shown in table 2. The scattered plot of the variables is as shown in figure 1 and regression graph is as shown in the figure 2.