Remote Sensing News
24.7K views | +2 today
Follow
Remote Sensing News
News about Remote Sensing Technologies...
Your new post is loading...
Your new post is loading...
Scooped by Elpidio I F Filho
Scoop.it!

Remote Sensing | Segmentation of Shadowed Buildings in Dense Urban Areas from Aerial Photographs

Segmentation of buildings in urban areas, especially dense urban areas, by using remotely sensed images is highly desirable. However, segmentation results obtained by using existing algorithms are unsatisfactory because of the unclear boundaries between buildings and the shadows cast by neighboring buildings. In this paper, an algorithm is proposed that successfully segments buildings from aerial photographs, including shadowed buildings in dense urban areas. To handle roofs having rough textures, digital numbers (DNs) are quantized into several quantum values. Quantization using several interval widths is applied during segmentation, and for each quantization, areas with homogeneous values are labeled in an image. Edges determined from the homogeneous areas obtained at each quantization are then merged, and frequently observed edges are extracted. By using a “rectangular index”, regions whose shapes are close to being rectangular are thus selected as buildings. Experimental results show that the proposed algorithm generates more practical segmentation results than an existing algorithm does. Therefore, the main factors in successful segmentation of shadowed roofs are (1) combination of different quantization results, (2) selection of buildings according to the rectangular index, and (3) edge completion by the inclusion of non-edge pixels that have a high probability of being edges. By utilizing these factors, the proposed algorithm optimizes the spatial filtering scale with respect to the size of building roofs in a locality. The proposed algorithm is considered to be useful for conducting building segmentation for various purposes

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

NASA - NASA Sees Fields of Green Spring up in Saudi Arabia

NASA - NASA Sees Fields of Green Spring up in Saudi Arabia | Remote Sensing News | Scoop.it
Saudi Arabia is drilling for a resource possibly more precious than oil by tapping hidden reserves of water in the Syrian Desert.

Over the last 24 years, it has tapped hidden reserves of water to grow wheat and other crops in the Syrian Desert. This time series of data shows images acquired by three different Landsat satellites operated by NASA and the U.S. Geological Survey.

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Spatial resolution: Fine, medium and coarse pixels

Spatial resolution: Fine, medium and coarse pixels | Remote Sensing News | Scoop.it

The spatial scale of remotely sensed data have been categorised into:

1 - Fine < 5m
2 - Medium 5 m - 100 m
3 - Coarse >100 m

 

......

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Remote sensing : Types of corrections

Remote sensing : Types of corrections | Remote Sensing News | Scoop.it

Once an image is acquired several types of corrections can be applied:

 

1 - Radiometric corrections

 1.1 - Atmospheric corrections

     a)Dark pixel correction (relative)
     b) Physics based correction (absolute)
  1.2 Bi-directional reflectance correction
2 - Geometric corrections

 

When do you need to correct?

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Remote sensing : Image acquisition

Remote sensing : Image acquisition | Remote Sensing News | Scoop.it

Before acquiring an image exploratory work needs to be conducted to determine what imagery is suitable for the questions being asked. The web sites of local image providers provide links to sensor specific web sites or to Google Earth tools which help viewing the areas of interest at the required spatial extent. Assessment of these web site can provide information if the required imagery are available on archive or if new imagery needs to be requested......

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Fundamentals of image processing and mapping approaches

Fundamentals of image processing  and mapping approaches | Remote Sensing News | Scoop.it

This section will explain the main image processing steps to map biophysical properties using remote sensing imagery derived from passive sensors. The steps described will focus on: ..........

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Improving the Accuracy of ASTER EO data - Geo: International

Improving the Accuracy of ASTER EO data - Geo: International | Remote Sensing News | Scoop.it
New research, undertaken by Britain\'s Royal Institution of Chartered Surveyors (RICS), in collaboration with the British Antarctic Survey, and unlocking the potential of the ASTER satellite-borne sensor, could help quantify glacial change in a systematic...
more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

West Antarctic Ice Shelves Tearing Apart at the Seams - University of Texas at Austin News

West Antarctic Ice Shelves Tearing Apart at the Seams - University of Texas at Austin News | Remote Sensing News | Scoop.it
University of Texas at Austin NewsWest Antarctic Ice Shelves Tearing Apart at the SeamsUniversity of Texas at Austin NewsReporting in the Journal of Glaciology, the UTIG team found that the extent of ice shelves in the Amundsen Sea Embayment...
more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

T. Ray's Vegetation Remote Sensing FAQ

1) What are the important spectral characteristics of vegetation that I should know about?
A: The cells in plant leaves are very effective scatterers of light because of the high contrast in the index of refraction between the water-rich cell contents and the intercellular air spaces.
Vegetation is very dark in the visible (400-700 nm) because of the high absorption of pigments which occur in leaves (chlorophyll, protochlorophyll, xanthophyll, etc.). There is a slight increase in
reflectivity around 550 nm (visible green) because the pigments are least absorptive there. In the spectral range 700-1300 nm plants are very bright because this is a spectral no-man's land between the
electronic transitions which provide absorption in the visible and molecular vibrations which absorb in longer wavelengths. There is no strong absorption in this spectral range, but the plant scatters strongly as mentioned above................

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Sense and Avoid for Drones Advances : Earth Imaging Journal: Remote Sensing, Satellite Images, Satellite Imagery

Sense and Avoid for Drones Advances : Earth Imaging Journal: Remote Sensing, Satellite Images, Satellite Imagery | Remote Sensing News | Scoop.it

In most countries, civilian air authorities such as the U.S. Federal Aviation Administration don’t permit UAVs to fly in the same airspace as conventional aircraft. A key stumbling block is the so-called sense-and-avoid problem—drones must be able to visually recognize other planes and then act to avoid midair collisions as well as human pilots can. Building computerized systems that can do that has “been the Holy Grail of the unmanned world,” says Rose Mooney, co-chair of RTCA’s Special Committee 203, an industry group working to make drone flights permissible in the United States........

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

The Cost of Free Earth Observation Data | Search for law notes

The Cost of Free Earth Observation Data | Search for law notes | Remote Sensing News | Scoop.it

A few weeks ago Space News ran an article entitled " ESA Data Access Policy Draws Mixed Reviews". The article details how the European Space Agency (ESA) and the European Commission have decided that almost all data from their earth observation satellites will be offered free of charge. The article states in part:

"[i]n a presentation outlining the rationale for the open-access policy [Susan Mecklenburg, mission manager for ESA's Soil Moisture and Ocean Salinity satellite] said the agency is facing increased demand for data as part of a global scientific examination of climate change"

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Regional Archaeology Possible with Hyperspectral Satellite Imagery | Spatial Sustain

Regional Archaeology Possible with Hyperspectral Satellite Imagery | Spatial Sustain | Remote Sensing News | Scoop.it
Researchers at Harvard University have discovered a new means to detect ancient settlements...
more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Detecting and Predicting Tamarisk Biomass in Colorado Using NASA EOS

Detecting and Predicting Tamarisk Biomass in Colorado Using NASA EOS | Remote Sensing News | Scoop.it

Detection of invasive plant species is vital for management practices and protection of sensitive areas that are affected by their influence on variables such as water tables, native plant communities, soil chemistry, and wildlife habitat. Moderate-resolution remotely sensed data has been utilized in mapping the distribution of various invasive plant species. The aim of this project was to complete this task with Landsat 5 time series analysis for Tamarix spp. (tamarisk) and to move forward by developing a methodology for predicting biomass using the Landsat 5 data and the predicted tamarisk distribution map. Occurrence points for tamarisk were represented by point locations derived from the Colorado Tamarisk Coalition coupled with field data collected by co-authors. Collaborative efforts with local organizations included the U.S. Geological Survey, Colorado Tamarisk Coalition, and the National Institute of Invasive Species Science. We used the acquired Landsat 5 scene to act as the study area boundaries encompassing LaJunta and surrounding areas within southeastern Colorado. We explored various tools and sequence methodologies such as Maximum Entropy (Maxent), boosted regression trees, and a new USGS product, the Software for Automated Habitat Modeling. Tamarisk distribution was successfully predicted using an ensemble method including boosted regression trees, generalized linear model, random forest, and multivariate adaptive regression splines. Biomass was predicted using field collected biomass values coupled with the distribution map and an abundance boosted regression tree model.

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Remote sensing to help grape growing

Remote sensing to help grape growing | Remote Sensing News | Scoop.it
The European Space Agency have developed a new service, known as GrapeLook, to help decide when and how much to irrigate vineyards. The technology uses a combination of Earth observation data and f...
more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Satellite Remote Sensing

Satellite Remote Sensing | Remote Sensing News | Scoop.it

Satellite remote sensing involves gathering information about features on the Earth's surface from orbiting satellites. These satellites carry two types of sensor systems known as "active" and "passive". A "passive" system generally consists of an array of small sensors or detectors, which record (as digital numbers), the amount of electro-magnetic radiation reflected and/or emitted from the Earth's surface. A multispectral scanner is an example of a passive system. An "active" system propagates its own electro-magnetic radiation, and measures (as digital numbers), the intensity of the return signal. Synthetic Aperture Radar (SAR) is an example of an active system.
The digital data acquired by the satellites is transmitted to ground stations and can be used to reconstitute an image of the Earth's surface not too dissimilar to an aerial photograph......

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Remote sensing : Masking unwanted areas

Remote sensing : Masking unwanted areas | Remote Sensing News | Scoop.it

When an image is corrected for radiometric and geometric distortions, areas that are not of interest for the mapping purpose can be masked out. Such areas are: water, clouds, shadows.

This can be done by:

Using existing map or GIS files of the feature to be masked
Using band ratios to extract the shaded areas
Using NIR band to extract water as it does not penetrate water
Delineating areas to be extracted

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Remote sensing : When to correct

Remote sensing : When to correct | Remote Sensing News | Scoop.it

The table below indicates the types of corrections that must be applied depending on the desired end use for your image......

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Remote sensing : Pre-processing sequence

Remote sensing : Pre-processing sequence | Remote Sensing News | Scoop.it

Before any information is derived from a satellite image set, a series of steps needs to be conducted:

1 - Image acquisition
2 - Planning image correction
3 - Radiomentric corrections
4 - Geometric corrections
5 - Masking unwanted areas

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

What is remote sensing?

What is remote sensing? | Remote Sensing News | Scoop.it

Remote sensing is any form of measurement where the measurement device is not in direct contact with the target. For example, the temperature of a water body can be measured directly by placing a thermometer in the water, or indirectly using a satellite sensor that measures emitted thermal energy from the water, which can be converted to temperature.

In terrestrial environments remote sensing techniques are usually applied to map: the type of material or feature(s) present on the ground (e.g. sand, grass, trees, forest) and their biophysical properties, including physical structure (height of trees, biomass) and bio-chemical properties (chlorophyll concentration, water content, amount of light absorbed for photosynthesis). A range of remote sensing instruments can be used in terrestrial environments, including passive sensors which rely on reflected sunlight or emitted thermal energy and active systems, such as radar or airborne laser, which generate their own source of illumination.

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Satellites finding: Volcanoes previously thought to be dormant are showing signs of unrest « Kipnews | Knowledge is power

Satellites finding: Volcanoes previously thought to be dormant are showing signs of unrest « Kipnews | Knowledge is power | Remote Sensing News | Scoop.it

The importance of global and frequent data coverage of volcanoes was highlighted in a recent article published in Science. Satellites are finding that volcanoes previously thought to be dormant are showing signs of unrest.

As the 2010 eruption of Eyjafjallajökull in Iceland demonstrated, volcanic eruptions can have consequences over large regions, so the global perspective offered by satellite systems is vital for monitoring volcanoes in remote and inaccessible terrain.......

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

NASA Sees Fields of Green Spring up in Saudi Arabia - Space Daily

NASA Sees Fields of Green Spring up in Saudi Arabia - Space Daily | Remote Sensing News | Scoop.it
UPI.comNASA Sees Fields of Green Spring up in Saudi ArabiaSpace DailyThis time series of data shows images acquired by three different Landsat satellites operated by NASA and the US Geological Survey.
more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Satellites Map Fine Aerosol Pollution Over China : Image of the Day

Satellites Map Fine Aerosol Pollution Over China : Image of the Day | Remote Sensing News | Scoop.it

Many types of aerosol particles circulate in the atmosphere, but one of the most damaging to human health is known as PM2.5, a technical term for microscopic bits of matter less than 2.5 microns in diameter (one thirtieth the width of a human hair). These small pollutants, which come mostly from burning fossil fuels and biomass, can lodge deep in the lungs, where they exacerbate a variety of respiratory and cardiovascular diseases.

 

Satellites offer a perspective on PM2.5 that is particularly useful when ground instruments are unavailable or offer limited information. With that in mind, researchers at Columbia University’s Earth Institute and Batelle Memorial Institute have developed maps based on satellite data that depict annual PM2.5 exposure in all of China’s provinces.

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

ScienceDirect.com - Procedia Engineering - Remote Sensing Techniques for Salt Affected Soil Mapping: Application to the Oran Region of Algeria

Satellite remote sensing of land affected by salinity, is a useful tool for decision support system through digital image processing for materials delineation (crystallography, detection of rocks, mineralogy, etc.). Today, with the advent of technology integration, merger, with optical data radar (InSAR and Signal Processing) actively contributed to the modelling of radar backscattering coefficient for the quantitative and qualitative salinity (modelled coefficients for models in relation to soil moisture, surface roughness). Thus, our approach has been to exploit the multi-spectral optical data from the LANDSAT ETM + (Enhanced Thematic Mapper) to map surface states, including indices of salinity and sodicity as: (BI: Brightness Index), NDSI: Normalized Difference Salinity Index, SI: Salinity Index, ASI: Aster Salinity Index (Agriculture), Index of Salinity (using GIS Geographic Information System and remote sensing), and finally the SSSI “Soil Salinity and Sodicity Index”. These indicators of salinity were tested for the Oran region in accordance with the spectral sensor ALI (Advanced Land Imager) satellite EO-1 (NASA from 2002 to 2006). Remote sensing helps identify salts are highly reflective and improved mapping of saline soil surface. Reports of More frequently used is the combined near infrared and visible (4 / 1 ETM), or bands in the infrared (7 / 4 or 7 / 5 ETM). Consequently, the spectral curves of the satellite ALI EO-1 show a match for saline soils and two test plots were chosen (Aquifer of Es-Sénia) to study corresponding with the measured data in-situ (electrical conductivity and pH) for the classification of saline soils [2]

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Araújo - Núcleo de Astronáutica: Satélites vão encorpar carteira da Embraer

Araújo - Núcleo de Astronáutica: Satélites vão encorpar carteira da Embraer | Remote Sensing News | Scoop.it

A entrada da Embraer no segmento espacial, com o projeto do Satélite Geoestacionário Brasileiro (SGB), poderá representar valor adicional superior a R$ 700 milhões em sua carteira de pedidos, que em 2012 está estimada em cerca de US$ 3,4 bilhões.

Desse valor, segundo o presidente da empresa, Luiz Carlos Aguiar, US$ 2 bilhões estão relacionados ao desenvolvimento do cargueiro militar KC-390 e outros US$ 1,1 bilhão aos programas de modernização de aeronaves da Força Aérea Brasileira (FAB) e da Marinha. O restante se divide entre as vendas do Super Tucano, das aeronaves de vigilância aérea e serviços.

O primeiro satélite SGB, que será adquirido no exterior, pelo prazo relativamente curto definido pelo governo para se ter o equipamento, estará voltado para comunicação governamental e internet em banda larga. O projeto já foi incluído no PPA de 2012-2015, com uma previsão de investimentos da ordem de R$ 716 milhões......

more...
No comment yet.
Scooped by Elpidio I F Filho
Scoop.it!

Landsat captures a global perspective on Earth's changes

Landsat captures a global perspective on Earth's changes.
more...
No comment yet.