High Dynamic Range in Entomological Scheimpflug Lidars

Samuel Jansson,Mikkel Brydegaard,Jeremie Zoueu,Benoit Kouakou,Jens Rydell

doi:10.1109/jstqe.2021.3062088

Samuel Jansson, Mikkel Brydegaard + Show 3 more

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https://doi.org/10.1109/jstqe.2021.3062088

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Abstract

Minimizing insecticide use, preventing vector diseases and facilitating biodiversity assessments are suitable applications of recent advances in photonic insect surveillance and entomological lidar. The tools also comprise a new window into fundamental aspect of the fascinating life and ecology of insects and their predators in situ. At the same time, it is evident that lidars are subject to finite detection range given by the instrument noise and saturation levels, and therefore, intervals of the biomass spectra are sectioned at different ranges. The Scheimpflug lidar allows an interesting trade-off between high sample rate and low pulse energy for retrieving wing beat harmonics and slow sample rates with high pulse energy for detecting small species far away. In this paper, we review and revise calibration, sizing and associated deficiencies, and report count rates to 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> insects/minute up to 2 km range. We investigate if and how high dynamic range can be exploited in entomological lidar and also how fast and slow sample rates could complement each other and capture a wider span of the biomass spectrum. We demonstrate that smaller insect can be detected further away by long exposures and show consistency between the captured biomass size spectra. However, we find unexpected discrepancies between short and long exposures in the range distributions. We found that vertebrates as well as specular insects can saturate signals. Error sources and limitations are elaborated on.

Highlights

AND MOTIVATIONT HE changing climate and the ongoing anthropogenic conversion of the biosphere [1] leads to extinction of pollinating insects as well as invasion of new territories by pestsManuscript received October 15, 2020; revised February 4, 2021 and February 22, 2021; accepted February 22, 2021
We mask by a threshold on the instantaneous lidar signal, Isig, when this exceeds the static signal plus three times the noise amplitude (>SNR = 3); Isig(r,t) > Imedian(r) + 5 IIQR(r)
We evaluated entomological lidar recordings with slow and fast sample rates, to investigate the dynamic and ranging properties

Summary

Introduction

AND MOTIVATIONT HE changing climate and the ongoing anthropogenic conversion of the biosphere [1] leads to extinction of pollinating insects as well as invasion of new territories by pestsManuscript received October 15, 2020; revised February 4, 2021 and February 22, 2021; accepted February 22, 2021. Date of publication February 25, 2021; date of current version April 5, 2021. A rapidly changing world requires swift measures for conservation ecology which in turn set demands for rapid diagnostics tools in situ. When it comes to entomological surveys we find ourselves blinded from the grand overview; what species to catch? Which trap design and lure to use? Where to position traps in the landscape and when to empty and with what frequency? The analysis of trap catches will take months of work by dedicated experts, even in a limited study When it comes to entomological surveys we find ourselves blinded from the grand overview; what species to catch? Which trap design and lure to use? How many? Where to position traps in the landscape and when to empty and with what frequency? The analysis of trap catches will take months of work by dedicated experts, even in a limited study

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