1.1 Optical Sensing and its Significance
Optical sensing measures and monitors the physical and chemical properties of objects through the utilization of light (Ferreira et al., 2017). Utilizing this non-destructive and non-invasive method, a vast array of parameters can be assessed, such as soil moisture, nutrient concentrations, chlorophyll levels, and more. Reflectance (the quantity of light reflected from a surface), transmittance (the quantity of light that passes through a material), fluorescence (the discharge of light by a substance subsequent to its excitation by light of an alternative wavelength), and absorption (the quantity of light absorbed by a substance) are among the numerous parameters that optical sensors are capable of discerning.
Precision agriculture relies heavily on optical sensing because, in contrast to pesticides, it furnishes farmers with up-to-date information regarding their fields and crops. It is possible to make informed judgments regarding crop management, including when to irrigate, fertilize, and apply, using this information. The application of optical sensing technology in agriculture is depicted in Figure 1.
Figure 1. A farmer operating a portable optical sensor within a field, alongside a drone that is also outfitted with optical sensors and hovers above the crops
1.2 Role in Modern Precision Agriculture Practices
Optical sensing plays a vital role in contemporary agricultural methods, allowing farmers to gather information regarding crops, soils, and pests. This data may then be utilized to make well-informed choices regarding irrigation, fertilization, pesticide usage, and other agricultural procedures. The choice of light wavelength impacts the specific information that may be acquired, such as using visible light to assess crop growth and development and employing infrared light to measure water content and detect plant stress.
Optical sensors are employed in several agricultural applications, such as tracking crop development, detecting pests and illnesses, evaluating crop vitality, and calculating crop production (Lee et al., 2010). This data can be utilized to create well-informed choices regarding irrigation, fertilization, pesticide usage, and other agricultural methodologies.
Optical sensing is utilized in the advancement of novel agricultural technology, including autonomous tractors and robotic harvesters. These technologies employ optical sensors to sense their environment and make informed judgments on movement and operation. This technology has the potential to enhance agricultural productivity, minimize expenses, and safeguard the ecosystem. Agricultural practitioners are employing unmanned aerial vehicles outfitted with multispectral sensors to oversee the condition of crops, detect areas that are experiencing stress or illness, focus on specific locations for irrigation and pesticide usage, generate maps indicating soil fertility, and administer fertilizer at varying rates (Sishodia et al., 2020). Optical sensors are employed to assess agricultural yields prior to harvest, enabling informed decision-making about marketing and logistics.