Remotely Piloted Aircraft (RPA) is presently in continuous development at a rapid pace. Unmanned Aerial Vehicles (UAVs) or more extensively Unmanned Aerial Systems (UAS) are platforms considered under the RPAs paradigm. Simultaneously, the development of sensors and instruments to be installed onboard such platforms is growing exponentially. These two factors together have led to the increasing use of these platforms and sensors for remote sensing applications with new potential. Thus, the overall goal of this paper is to provide a panoramic overview about the current status of remote sensing applications based on unmanned aerial platforms equipped with a set of specific sensors and instruments. First, some examples of typical platforms used in remote sensing are provided. Second, a description of sensors and technologies is explored which are onboard instruments specifically intended to capture data for remote sensing applications. Third, multi-UAVs in collaboration, coordination, and cooperation in remote sensing are considered. Finally, a collection of applications in several areas are proposed, where the combination of unmanned platforms and sensors, together with methods, algorithms, and procedures provide the overview in very different remote sensing applications. This paper presents an overview of different areas, each independent from the others, so that the reader does not need to read the full paper when a specific application is of interest

Overview and Current Status of Remote Sensing Applications Based on Unmanned Aerial Vehicles (UAVs)

Spectral imaging is a technology that integrates conventional imaging and spectroscopy to get both spatial and spectral information from an object. Although this technology was originally developed for remote sensing, it has been extended to the biomedical engineering field as a powerful analytical tool for biological and biomedical research. This review introduces the basics of spectral imaging, imaging methods, current equipment, and recent advances in biomedical applications. The performance and analytical capabilities of spectral imaging systems for biological and biomedical imaging are discussed. In particular, the current achievements and limitations of this technology in biomedical engineering are presented. The benefits and development trends of biomedical spectral imaging are highlighted to provide the reader with an insight into the current technological advances and its potential for biomedical research.

https://www.spiedigitallibrary.org/journals/journal-of-biomedical-optics/volume-18/issue-10/100901/Review-of-spectral-imaging-technology-in-biomedical-engineering--achievements/10.1117/1.JBO.18.10.100901.pdf

Review of spectral imaging technology in biomedical engineering: achievements and challenges

The miniaturization of electronics, computers and sensors has created new opportunities for remote sensing applications. Despite the current restrictions on regulation, the use of unmanned aerial vehicles equipped with small thermal, laser or spectral sensors has emerged as a promising alternative for assisting modeling, mapping and monitoring applications in rangelands, forests and agricultural environments. This review provides an overview of recent research that has reported UAV flight experiments on the remote sensing of vegetated areas. To provide a differential trend to other reviews, this paper is not limited to crops and precision agriculture applications, but also includes forest and rangeland applications. This work follows a top-down categorization strategy and attempts to fill the gap between application requirements and the characteristics of selected tools, payloads and platforms. Furthermore, correlations between common requirements and the most frequently used solutions are highlighted.

https://www.mdpi.com/2072-4292/6/11/11051/pdf

UAV Flight Experiments Applied to the Remote Sensing of Vegetated Areas

Unmanned aerial vehicles have become popular platforms for remote-sensing applications, particularly when spaceborne technology, manned airborne techniques, and in situ methods are not as efficient...

Recent applications of unmanned aerial imagery in natural resource management

Near-infrared (12,500-4,000 cm-1; 800-2,500 nm) spectroscopy is the hallmark for one of the most rapidly advancing analytical techniques over the last few decades. Although it is mainly recognized as an analytical tool, near-infrared spectroscopy has also contributed significantly to physical chemistry, e.g., by delivering invaluable data on the anharmonic nature of molecular vibrations or peculiarities of intermolecular interactions. In all these contexts, a major barrier in the form of an intrinsic complexity of near-infrared spectra has been encountered. A large number of overlapping vibrational contributions influenced by anharmonic effects create complex patterns of spectral dependencies, in many cases hindering our comprehension of near-infrared spectra. Quantum mechanical calculations commonly serve as a major support to infrared and Raman studies; conversely, near-infrared spectroscopy has long been hindered in this regard due to practical limitations. Advances in anharmonic theories in hyphenation with ever-growing computer technology have enabled feasible theoretical near-infrared spectroscopy in recent times. Accordingly, a growing number of quantum mechanical investigations aimed at near-infrared region has been witnessed. The present review article summarizes these most recent accomplishments in the emerging field. Applications of generalized approaches, such as vibrational self-consistent field and vibrational second order perturbation theories as well as their derivatives, and dense grid-based studies of vibrational potential, are overviewed. Basic and applied studies are discussed, with special attention paid to the ones which aim at improving analytical spectroscopy. A remarkable potential arises from the growing applicability of anharmonic computations to solving the problems which arise in both basic and analytical near-infrared spectroscopy. This review highlights an increased value of quantum mechanical calculations to near-infrared spectroscopy in relation to other kinds of vibrational spectroscopy.

/pdf/breakthrough-potential-in-near-infrared-spectroscopy-spectra-4wpjqxx2w8.pdf

Breakthrough Potential in Near-Infrared Spectroscopy: Spectra Simulation. A Review of Recent Developments

Multi-spectral video endoscopy system for the detection of cancerous tissue

This paper presents an airborne multi-spectral imaging sensor which is able to simultaneously capture three visible and three near infrared channels. The first prototype was integrated in a Schiebel CAMCOPTER® S-100 VTOL (Vertical Take-Off and Landing) UAV (Unmanned Aerial Vehicle) for inflight tests. A low cost version of the initial multi-spectral imaging system was developed to fit into a more compact UAV. The imaging system captures six bands with a minimal spatial resolution of approx. 10cm × 10cm (depending on altitude). Results indicate that the system is able to resist the high vibration level during flight and that the actively stabilized camera gimbal compensates for rapid roll/tilt movements of the UAV. After image registration the acquired images are stitched together for land cover mapping and flight path validation. Moreover the system is able to distinguish between different types of vegetation and soil.

UAV-based measurement of vegetation indices for environmental monitoring

Application of Design of Experiment for Detection of Meat Fraud with a Portable Near-Infrared Spectrometer

Monitoring the soil composition of agricultural land is important for maximizing crop-yields. Carinthian Tech
Research, Schiebel GmbH and Quest Innovations B.V. have developed a multi-spectral imaging system that
is able to simultaneously capture three visible and two near infrared channels. The system was mounted on
a Schiebel CAMCOPTER ® S-100 UAV for data acquisition. Results show that the system is able to classify
different land types and calculate vegetation indices.

UAV-based environmental monitoring using multi-spectral imaging

Video endoscopy allows physicians to visually inspect inner regions of the human body using a camera and only
minimal invasive optical instruments. It has become an every-day routine in clinics all over the world. Recently a
technological shift was done to increase the resolution from PAL/NTSC to HDTV. But, despite a vast literature on invivo
and in-vitro experiments with multi-spectral point and imaging instruments that suggest that a wealth of information
for diagnostic overlays is available in the visible spectrum, the technological evolution from colour to hyper-spectral
video endoscopy is overdue. There were two approaches (NBI, OBI) that tried to increase the contrast for a better
visualisation by using more than three wavelengths. But controversial discussions about the real benefit of a contrast
enhancement alone, motivated a more comprehensive approach using the entire spectrum and pattern recognition
algorithms. Up to now the hyper-spectral equipment was too slow to acquire a multi-spectral image stack at reasonable
video rates rendering video endoscopy applications impossible. Recently, the availability of fast and versatile tunable
filters with switching times below 50 microseconds made an instrumentation for hyper-spectral video endoscopes
feasible. This paper describes a demonstrator for hyper-spectral video endoscopy and the results of clinical
measurements using this demonstrator for measurements after otolaryngoscopic investigations and thorax surgeries. The
application investigated here is the detection of dysplastic tissue, although hyper-spectral video endoscopy is of course
not limited to cancer detection. Other applications are the detection of dysplastic tissue or polyps in the colon or the
gastrointestinal tract.

Raimund Leitner

Papers

Multi-spectral video endoscopy system for the detection of cancerous tissue

UAV-based measurement of vegetation indices for environmental monitoring

Application of Design of Experiment for Detection of Meat Fraud with a Portable Near-Infrared Spectrometer

UAV-based environmental monitoring using multi-spectral imaging

High-sensitivity hyperspectral imager for biomedical video diagnostic applications