Development of portable plant components measurement instrument based on near-infrared spectroscopy

In the paper a portable multi-function instrument was developed, which can quantitatively measure the content of plant components in accordance with different components of plant leaves have a different absorption on different NIR spectra. The instrument is mainly composed of an independent leaves clamp and a multi-function host. Based on the method of Dual-wavelength the integral type leaves clamp was designed in the paper, which was composed of dual-LED, spectra filter, lens, photoelectric receiving device and so on. The design simplified the optical structure, enhanced the stability of apparatus, and further improved the signal-to-noise ratio and precision. The host mainly contained four parts, including micro-control system, driving circuit of light source, photoelectric conversion and signal conditioning circuit and LCD display circuit. In addition, in the structure of host an open data interface was reserved for very easily connect to the leaves clamp, which achieved real-time, quick and nondestructive measurement of different plant components (chlorophyll and moisture of plant leaves were basically studied in this paper. The characteristic wavelengths 680nm and 940nm was used to measure chlorophyll, 880nm and 974nm was used to measure moisture). In the calibration experiment the instrument have a excellent results of the prediction. The correlation coeffieient between the prediction value and the true value of moisture content and chlorophyll content repectively is 0.86 and 0.92. The standard error of prediction repectively is 0.016 and 0.020.