Image processing
One of the latest software’s of image processing based on the analysis of surface
texture is ENVI1. The software works based on the value of the reflected wavelengths
from various surfaces. The principal component analysis (PCA) is one of the
commands of ENVI. PCA is a statistical method for data reduction. Levels of the PCA
process are:
1. Calculation of the variance and covariance matrix (or correlation) of the image
2. Eigenvector and the eigenvalue matrix extraction.
The software default setting is to calculate the eigenvalue of good pixels for
images by PCA method. As much as the image of the plant section is smoother and
more uniform in color, its eigenvalue is higher. This number is known as PC1
(Alavipanah, 2009).