Optical remote sensing

Remote sensing can be performed using passive or active techniques. While changes in the spectral distribution of the background radiation (e.g., the sunlight) are analysed using passive techniques, changes in the radiation transmitted by the equipment due to interactions with the measurement volume are studied in active techniques. These concepts can be illustrated by a simple example. 

Remote-sensing systems can be mounted on different platforms depending on the type of measuring task. A sensor mounted on a satellite can have global coverage. Many of the numerous satellites that orbit above the 

In Fig.6.71 different passive and active remote-sensing techniques are illustrated. The selective reflection of solar radiation from the earth s surface, the absorption or the thermal emission of the atmosphere can be studied with passive techniques. Active techniques frequently make use of laser or microwave radiation. The transmission or scattering of such radiation can yield information on the atmosphere or the land and sea surface. 

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Chan K., Ito H., Inaba H., Furuya T., Ten-kilometer long fiber-optic remote sensing of methane gas by near infrared absorption, Appl. Phys. B 1985 38 11. 

Optical Remote Sensing Science and Technology, Walter Egan... 

Chen J.M. Liu J. Leblanc S.G. Lacaze R. and Roujean J.-L. (2003). Multi-angular optical remote sensing for assessing vegetation structure and carbon absorption. Remote Sensing of Environment, 84(4), 516 - 525. 

Jacobsen, A. (2000) Analysing airborne optical remote sensing data from a hyperspectral scanner and implications for environmental mapping and monitoring - results from a study of casi data and Danish semi-natural, dry grasslands. PhD Thesis. National Environmental Research Institute, Denmark, 148 pp. 

The resulting continuum is very broad, since it could be measured from 230 nm in the ultraviolet to 4.5 pm in the mid-infrared. The combined spectrum is shown in Fig. 15.8. The fast decrease of the spectrum up to 2.5 pm (4 orders of magnitude between 800 nm and 2.5 pm) slows down beyond 2.5 pm, with only one order of magnitude drop between 2.5 and 4.5 pm. On the spectrum, the absorption band of water between 1.8 and 2.5 pm is clearly visible, showing the potential of the white-light for optical remote sensing in the atmosphere. 

Siegel, H., Gerth, M., 2008. Optical remote sensing applications in the enclosed Baltic Sea. In Barale, V., Gade, M. (Eds.), Remote Sensing of European Seas, Chapter 7 Springer Netherlands, p. 514. 

This book reviews methods for measuring airborne compounds and includes recent developments from experts in the field. Topics range from optical remote sensing to VOC sampling and analysis to visibility research in national parks. 

Optical remote sensing (ORS) technologies, employing infrared spectral analysis techniques, have been utilized in the development of chemical agent standoff detection technologies. Within the ORS technologies, there are two types of remote sensing systems passive and active (laser). The section below only looks at the passive system, which employs a Fourier Transform Infrared (FTIR) spectrometer. 

In this paper, a fiber optic remote sensing multiplexed oxygen monitoring system is designed based on tunable diode laser absorption spectroscopy technique. It is an intrinsic sensing method to provide long term stability without the need of frequent calibrations. 

R. H. Hunt, in Optical Remote Sensing and Applications to Environmental and Industrial Safety Problems, Apr. 6—8, 1992, Air and Waste Management Association, Pittsburgh, Pa., 1992, p. 446. 

Weikamp C (2005) lidar range-resolved optical remote sensing of the atmosphere. Springer, New YotIc... 

A.F.H. Goertz, J. Wellman, W. Barnes Optical remote sensing of the Earth. Proc. IEEE 73 (June 1985)... 

We will discuss two active remote-sensing techniques for the atmosphere — the long-path absorption technique and the lidar technique. However, we will first consider a passive technique, in which lasers play an important part in the detection scheme. This optical heterodyne technique is even more frequently used for signal recovery in connection with the active optical remote-sensing methods. The field of laser monitoring of the atmosphere is covered in several monographs and articles [10.70-10.76]. 

M.C. Alarcon, H. Ito, H. Inaba All-optical remote sensing of city gas through CH4 gas absorption employing a low-loss optical fibre link and an... 

A number of different fiber-coupled probe designs for measuring Raman spectra are commercially available [73,174-183]. Although their architectures can be quite different, there are some basic functions they all must address, along with optional features only some provide. All fiber probes for Raman spectroscopy aim to capitalize on the same basic benefits, namely all-optical remote sensing and flexible sampling convenience. 

J Barbillat, P Dhamelincourt, M Delhaye, E Da Silva. Raman confocal microprobing, imaging and fibre-optic remote sensing A further step in molecular analysis. J Raman Spectrosc 25 3-11, 1994. NQ Dao, M Jouan. The Raman laser fiber optics (RLFO) method and its applications. Sensors Actuators B Chem 11 147-160, 1993. 

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