Measurement Of Chlorophyll Content And Distribution In Cucumber Leaves Using Hyper-spectral Imaging Technique

Chlorophyll is one of basic components of plant. It is sensitive Indicator of plant environmental stress and growth. When nutrition deficiency or other Interference happened on plant, the concentration and distribution of chlorophyll were changed. As an important matter containing nitrogen in plant, the chlorophyll also indicates the nitrogen absorption and utilization. In stead of the time-consuming, costly chemical analysis method, to develop a new approach to rapidly, accurately and non-destructive detect the concentration and distribution of chlorophyll is meaningful.By taking cucumber leaf as the research object, hyper-spectral imaging was used to detect concentration and distribution of chlorophyll in cucumber leaf in the study. The main research results were as fallows:1 Red edge parameters and vegetation index were extracted and studied, there was some relationship between the parameters and the concentration of chlorophyll, but it was not significant. The result showed that the information reflected from these parameters was not complete. Those parameters had to be corrected in special condition and could not used to determine the concentration of chlorophyll directly.2 10 principal components factors (PCs) and 8 independent component factors (ICs) were calculated by PCA (Principal Component Analysis) and ICA (Independent Component Analysis). Multiple linear regression was applied to build the quantitative model with the PCs and ICs. The correlation coefficient (R) was, respectively,0.827 and 0.831. Stepwise regression was applied to compare the effect of ICA and PCA. The result shows that R is up to 0.766 when only using one IC. ICA was better in detecting the concentration of chlorophyll, and had advantages in separating the signal of chlorophyll in hyper-spectral image.3 Based on the model, distribution map of chlorophyll in cucumber leaf was plotted. The result showed calculating distribution map of chlorophyll in cucumber leaf was feasible, and laid a foundation for the further study.4 Software for hyper-spectral image processing based on redevelopment of ENVI was designed. In accordance with requirement of agricultural products inspection, the system possessed the following functions:batch calibration, region of interest extraction, feature extraction, independent component image calculates and data output. The Software could provide convenience for data process of hyper-spectral image.In this paper, detection of concentration and distribution of chlorophyll in cucumber leaf and ICA approaching on the hyper-spectral image were studied. The result provided sufficient theoretical basis for chlorophyll detection and hyper-spectral image processing. It was meaningful for promoting the automation and intelligent in nutrition, plant insect pests and growth vigor diagnosis of plant.