multispec remote sensing tutorial manual

In spite of the large number of successful works that have been applied to agroforestry and related areas using low-cost passive imagery sensors-such as visible (RGB) and near infrared (NIR)-many applications require higher spectral fidelity that only multispectral and hyperspectral sensors can offer. Moreover, research works focusing the symbiosis between UAV-hyperspectral for agriculture and forestry applications are reviewed, just before the paper’s conclusions.

With the goal of simplifying hyperspectral data processing-by isolating the common user from the processes’ mathematical complexity-several available toolboxes that allow a direct access to level-one hyperspectral data are presented. Pre-flight operations and post-flight pre-processing are pointed out as necessary to ensure the usefulness of hyperspectral data for further processing towards the retrieval of conclusive information. Then, hyperspectral acquisition devices are addressed, including sensor types, acquisition modes and UAV-compatible sensors that can be used for both research and commercial purposes. Firstly, the advantages of hyperspectral data over RGB imagery and multispectral data are highlighted. Considering the aforementioned topics and the goal of providing a global view focused on hyperspectral-based remote sensing supported by UAV platforms, a survey including hyperspectral sensors, inherent data processing and applications focusing both on agriculture and forestry-wherein the combination of UAV and hyperspectral sensors plays a center role-is presented in this paper. Further steps regarding hyperspectral data processing must be performed towards the retrieval of relevant information, which provides the true benefits for assertive interventions in agricultural crops and forested areas.

The hyperspectral sensors’ ability for measuring hundreds of bands raises complexity when considering the sheer quantity of acquired data, whose usefulness depends on both calibration and corrective tasks occurring in pre- and post-flight stages. Meanwhile, hyperspectral technology developments have been consistently resulting in smaller and lighter sensors that can currently be integrated in UAS for either scientific or commercial purposes. More recently, UAS have emerged as a very popular and cost-effective remote sensing technology, composed of aerial platforms capable of carrying small-sized and lightweight sensors. This kind of high-resolution spectroscopy was firstly used in satellites and later in manned aircraft, which are significantly expensive platforms and extremely restrictive due to availability limitations and/or complex logistics. However, it lacks the spectral range and precision to profile materials and organisms that only hyperspectral sensors can provide. Traditional imagery-provided, for example, by RGB and/or NIR sensors-has proven to be useful in many agroforestry applications.

Multispec remote sensing tutorial manual