History And Development of Remote sensing



History and Development of Remote Sensing

1800: Infra Red portion of Electromagnetic spectrum discovered.

1801: Ultraviolet part of electromagnetic spectrum discovered.

1839: Invention of photography by Daguerre.

1847: Characteristics of infrared radiation discovered.

1858: Photography from balloons by tournachon.

1871: Dry film photography invented.

1873: Maxwell developed the theory of electromagnetism

1885: Colour photography done by colour separation method.

1898: Mathematical analysis of photograph done by Laussedat for mapping.

1909: Photography by airplanes was started

1914-18: Aerial reconnaissance started during world war-I

1920-30: Aerial photography and photogrammetry developed for military reconnaissance and mapping.

1931: Black and white Infra red sensitive film available

1935: First colour film “ KODACHROME” was available

1930-40: Development of RADAR (Radio detective and Ranging) for air traffic control

1942: First colour Infra Red (IR) NTFPs film was available

1939-45: Images in nonviable portion of electromagnetic spectrum (Thermal and Microwave) used during world

War-II. Specialized training in Acquisition and airphoto interpretation was started.

1940-50: Military research and development activities took place.

1950-60: Development of sideways-looking airborne RADAR (SLAR) and Synthetic Aperture RADAR (SAR), Imaging RADAR system.

1956: Colour IR film was first used in agriculture.

1960-70: The word “RS” was used for the first time.

1960: Launch of TIROS-I American weather satellite.

1972: Launch of Earth Resources technology satellite (ETRS) on July 23, 1972 by National Aeronautical and Space administration (NASA) subsequently renamed LANDSAT-I.

1973: Launch of SKYLAB, the first manned American space station.

1970-80: Rapid advances in digital image processing (DIP) due to powerful microprocessor based computers available.

1975: Manual of RS (First Edition) published by American Society of photogrammetry.

1978: Launch of SEASAT-I, an American Oceanographic satellite.

1980: Launch of USSR METEOR satellite.

1980-90: Launch of LANDSAT-4, second generation of LANDSAT series with new sensor.

1986: Launch of French Earth observation satellite (SPOT)

In INDIA:

1979,- H|BHASKARA,

1988: IRS-IA,

1994: IRS-P2

1995: IRS-IC

1999: IRS-ID

IDEAL REMOTE SENSING SYSTEM.

The Figure of the ideal Remote Sensing System is as follows.

1. Uniform energy source. 4. Super Sensor.

1) A Uniform Energy Source:

Electromagnetic energy of all wave lengths ( ) and known uniform radiance is produced by an ideal source.

2) A non interfering Atmosphere:

The energy propagates from the source, without atmospheric modification or loss to a homogeneous object, ideally this would hold irrespective of wave length, time, place and sensing altitude involved.

3) A series of unique energy interactions at the earth’s surface:

The energy of various wavelengths selectively interacts with the object, resulting in a unique return signal of reflected and emitted energy.

4) A Super Sensor:

The returned signal propagates, again without atmospheric modification, to a sensor that responds to energy of all wavelengths of any radiance level. This super sensor would be simple and reliable, and be accurate and economical to operate.

5) A real time data handling system:

In real time, a radiance versus wave length response is recorded, processed into an interpretable format, and recognized as being unique to the particular object type observed in its particular physical, chemical and biological state. That is, the sensor data are accurately processed into resource information.

6) Multiple Data Users:

The information obtained about the particular earth surface feature is made readily available, in useful form, to users.

REAL TIME: It refers to images or data made available for inspection simultaneously with their acquisition.

Real Remote Sensing System

1) The energy Source:

Solar radiation level vary with respect to time and location, and different earth surface materials emit energy to varying degrees of efficiency. Passive Remote sensing system rely on non uniform energy source, while active system have some control over the sources of energy used. In all real remote sensing systems the sources of energy used are generally non uniform with respect to wave lengths and its properties vary with time and location. So, we normally must calibrate for source characteristics on a mission by mission basis or ideal with relative energy units sensed at any given time and location.

2) The atmosphere:

The atmosphere normally compounds (Combine or mis)the problems introduced by energy source variation. To some extent the atmosphere always modifies the strength and spectral distribution of energy received by a sensor. The importance of these effect is a functuion of wave length involved, the sensor used and the application for which the sensing will be used. So, some form of calibration is particularly important in those applications where repetitive observations of the same geographic area are involved.

3) The energy/matter interactions at the earth’s surface:

Remote sensing would be simple is every material reflects and /or emits energy ina unique known way. The spectral response pattern (spectral signature) play a vital role in detecting, identfying and analyzing earth surface materials. Fundamentally different materail types can have great spectral similarity, making differentiation difficult.

Spectral Signature: Spectral characteristics of an object in a scene (e.g., tone, texture), which refers that each object and identifiable manner. Spectral response is preferred: The response of a sensor to a particular wavelength if electromagnetic radiation.

4) The Sensor:

An ideal sensor does not exists. There are many kinds of sensors and no single sensor is sensitive to all wavelengths. All real sensors have fixed limits of spectral sensitivity. The resolution of the sensor also has limit to separate the surface features from surroundings. This limit is known as spatial resolution of a sensor. The development is on its way to male it separable from one another with 1m resolution.

Resolution: Ability to separate or discriminate closely spaced objects on an image or photograph. (Also called spatial resolution)

5) Data Handling:

The capability of current remote sensor and development of super computers and powerful personal computers has made us very easy to handle huge amount of data. The data formats are also very easily transferable from one to another by development of new software’s. Human interventions in data processing and analysis will continued to be the productive application of Remote Sensing.

6) The Multiple data users:

The data produced by Remote sensing procedures is the information for all that uses it. The users must know how to generate, interpret and how best to use it. As new applications continue to be developed and implemented, increasing numbers of users are becoming aware of potential of RS techniques. As a result RS has becoming an essential tool in many programs like resource management, environmental monitoring engineering, exploration etc.

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Radiant

(5) Real Time Data Processing

Homogeneous Object.

(3)Unique energy interaction at earth surface features

Absorbed Energy

Transmitted Energy

(2) Non Interfering Atmosphere

Unique Response for each feature

Reflected Energy

Emitted Energy

(6) Multiple Data Users

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