Design of portable instrument for measuring leaf area index based on hemispherical photography

Abstract

In pursuit of an efficient and precise method for measuring the Leaf Area Index (LAI), this paper designs and implements a portable LAI measurement instrument based on hemispherical photography, designated as LAI-HP. Constructed upon an embedded platform, this device integrates advanced functionalities of image acquisition, processing, and storage in a single compact unit. Not only does it simplify operational procedures, enabling users to readily master the measurement technique, but it also ensures high accuracy by providing exact analysis of hemispherical canopy images, thereby rapidly and accurately extracting the leaf area index. Comparative experiments reveal a highly significant correlation between the measurement results of LAI-HP and those obtained from the LAI-2200C (R = 0.889, RMSE = 0.441), demonstrating its capability to meet the requirements for LAI measurements in major ecosystems such as farmlands and forests.