Brussels Photonics (B-PHOT) and Flanders Make, Department of Applied Physics and Photonics, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
Robotech, Via Mazzini 82, 19038 Sarzana, SP, Italy.
Sensors (Basel). 2023 Feb 23;23(5):2470. doi: 10.3390/s23052470.
Sustainably using resources, while reducing the use of chemicals, is of major importance in agriculture, including turfgrass monitoring. Today, crop monitoring often uses camera-based drone sensing, offering an accurate evaluation but typically requiring a technical operator. To enable autonomous and continuous monitoring, we propose a novel five-channel multispectral camera design suitable for integrating it inside lighting fixtures and enabling the sensing of a multitude of vegetation indices by covering visible, near-infrared and thermal wavelength bands. To limit the number of cameras, and in contrast to the drone-sensing systems that show a small field of view, a novel wide-field-of-view imaging design is proposed, featuring a field of view exceeding 164°. This paper presents the development of the five-channel wide-field-of-view imaging design, starting from the optimization of the design parameters and moving toward a demonstrator setup and optical characterization. All imaging channels show an excellent image quality, indicated by an MTF exceeding 0.5 at a spatial frequency of 72 lp/mm for the visible and near-infrared imaging designs and 27 lp/mm for the thermal channel. Consequently, we believe our novel five-channel imaging design paves the way toward autonomous crop monitoring while optimizing resource usage.
可持续利用资源，同时减少化学品的使用，在农业中非常重要，包括草坪监测。如今，作物监测通常使用基于摄像头的无人机感应，提供准确的评估，但通常需要技术操作人员。为了实现自主和连续监测，我们提出了一种新颖的五通道多光谱相机设计，适合集成到照明灯具中，并通过覆盖可见、近红外和热波长带，实现多种植被指数的感应。为了限制摄像机的数量，并且与显示小视场的无人机感应系统相反，提出了一种新颖的宽视场成像设计，其视场超过 164°。本文介绍了五通道宽视场成像设计的开发，从设计参数的优化开始，逐步发展到演示设置和光学特性的研究。所有成像通道都显示出出色的图像质量，可见光和近红外成像设计的调制传递函数（MTF）超过 0.5，在空间频率为 72 lp/mm 时，而热通道的 MTF 超过 0.5，在空间频率为 27 lp/mm 时。因此，我们相信我们的新型五通道成像设计为优化资源利用的自主作物监测铺平了道路。
