CPC G01B 17/02 (2013.01) | 5 Claims |
1. A method for detecting a thickness of a tree canopy based on an ultrasonic echo signal, comprising:
sending, by an ultrasonic sensor, an ultrasonic emission signal toward the tree canopy;
forming the ultrasonic echo signal by the tree canopy reflecting the ultrasonic emission signal; and
acquiring the ultrasonic echo signal, the ultrasonic echo signal being composed of voltage data and corresponding time data thereof,
wherein the voltage data generates an array Vi=[V1, V2, V3, . . . , Vn], the corresponding time data generates an array T=[T1, T2, T3, . . . , Tn], i=1, 2, 3, . . . , n, and a calculation formula of the thickness L of the tree canopy is as follows:
wherein L is the thickness of the tree canopy, in meters, vo is a local ultrasonic propagation rate, in meters/second, Tx is a first effective peak time of the ultrasonic echo signal, in seconds, Ty is a last effective peak time of the ultrasonic echo signal, in seconds, k is a correction coefficient, when a leaf area index (LAI) of the tree canopy meets 1.5≤LAI≤4.0, k=1, when the leaf area index of the tree canopy is
and when the leaf area index of the tree canopy is
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