Remote sensing is the science of obtaining information about objects without physical contact. This document provides an overview of remote sensing, including how satellites acquire images using sensors to detect electromagnetic radiation from the Earth's surface. Specific applications of remote sensing discussed include using thermal imaging to assess crop conditions by measuring surface temperature, and using visible and infrared bands to monitor agriculture and land use from above.

1. A SEMINAR REPORT ON REMOTE SENSING

6. The need for Education in Remote Sensing :- Pollution, population growth exceeding the support capability of the land, loss of biodiversity and global climate change are only few of the problems that face today’s and tomorrow’s generations. Remote sensing and related technologies can contribute to our understanding of these problems as well as tot eh implementation of practical solutions

7. Meanwhile countries are becoming increasingly aware that long term economic viability requires a balanced, informed strategy for the exploitation of natural resources forecasting agricultural yields, and developing new energy sources. In order to meet these challenges, we need professional who are familiar with the capabilities and limitations of the geospatial technologies. This includes researchers who can develop new methodologies and applications, as well as technicians and practitioners who can apply proven techniques to specify problems. Thus, it is more important than ever that remote sensing educational programs provide an adequate exposure to modern technologies, as well as solid grounding in remote sensing theory and principles.

9. This can be seen as a peak in the green band in the reflectance spectrum for green grass above. The spectrum also shows that grass reflects even more strongly in the infrared part of the spectrum. While this can't be detected by the human eye, it can be detected by an infrared sensor.Instruments mounted on satellites detect and record the energy that has been reflected. The detectors are sensitive to particular ranges of wavelengths, called 'bands'. The satellite systems are characterised by the bands at which they measure the reflected energy. The Landsat TM satellite, which provides the data used in this project, has bands at the blue, green and red wavelengths in the visible part of the spectrum .

10. Another feature that characterises each satellite system is its footprint or pixel size. This is the smallest area on the ground for which it can record the reflected energy. For every 30m by 30m plot of land, the Landsat TM scanner records a number for each of the seven bands, which is the average intensity of the reflected energy for the features in that plot of land. The satellite detectors measure the intensity of the reflected energy and record it as a number between 0 and 255.

13. When the red, green and blue bands of an image are assigned to the same colours on the computer screen, a true-colour image is formed. These images look like aerial photographs, since they indicate the true colours of objects – green trees and grass and brown soil. When mixtures of the visible and infrared bands are assigned to the red, green and blue colours on the computer, false-colour images are formed. In these images, the different colours on the screen represent different intensities in the wavelength bands that are assigned to each screen colour. As well as deciding which image band to assign to which screen colour, choices can be made about how to relate the range of numbers recorded by the satellite to the 256 levels of each colour on the computer screen.0 The way the range of digital numbers in the image is related to the computer colour levels is called 'image enhancement'.

15. Introduction to Remote Sensing for Agriculture :- Remote sensing is the ability to measure the properties of an object without touching it. Almost all of the applications of remote sensing to date have been based on observing crops in distinct areas of the electromagnetic spectrum. The spectrum is represented in the figure below. Agricultural remote sensing is commonly done in the visible, near-infrared and thermal infrared portions of the spectrum; however, new applications in the microwave area are under development.

16. Regions within the Visible and Infrared Spectrum Visible Infrared 0.40-0.45 um Violet 0.7 - 3.0 um Near-Infrared 0.45-0.50 um Blue 3.0 - 14 um Thermal-Infrared 0.50-0.55 um Green 14.0 - 1000 um Far-Infrared 0.55-0.60 um Yellow 0.60-0.65 um Orange 0.65-0.70 um Red

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