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India Launches World's First Stereo Imaging Satellite
sgups writes "India will tomorrow inaugurate a new launch pad at its Satish Dhawan space port near Chennai, on the south-east coast, by putting the world's first stereographic mapping satellite into orbit.
The most innovative feature of the 1.6-tonne Cartosat-1 is its pair of cameras, which will give stereo images of the earth's surface that can distinguish features down to 2.5 metres across. They will directly generate three-dimensional maps that have until now been achievable only indirectly, by combining data from a large number of satellite passes over the same place.
"Such a stereographic imaging system does not exist in the civil sector anywhere else," says Mr Nair, chairman of the Bangalore-based Indian Space Research Organisation (Isro). "It will give information about heights that will be very useful in applications such as planning power lines."
Cartosat-1 will join what is already the world's largest cluster of non-military remote sensing satellites. Six Indian spacecraft are already observing the earth with a wide range of instruments."
Weather Radar on birds with ISAR can do this.
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http://www.madsci.org/posts/archives/2004-09/1094
I've exchanged email with NOAA about hurricane photos and have been told that some of them are inface ISAR radar images that have been colored.
The blurb there for the story sounds like a Press Release there from Mr Nair, chairman of the Bangalore-based Indian Space Research Organisation (Isro).
Due to spacecraft (or aircraft) motion, stereo pairs are generated along the flightpath if sequential images overlap. In many systems, each image n generates overlap with both image n+1 and n+2. Given the ability to launch two cameras, why not launch a single camera with more capabilities? Another minor, and common, error is that the Cartosat-1 has a 2.5m pixel on its CCD, which does not transalate into a 2.5m "resolution." CCD resolution corresponds to Ground Sampled Distance (GSD), or the amount of ground sampled on one pixel. Ground resolved distance, (GRD), measures the highest frequency visible in the image and is what we normally think of as "resolution." As a result, for electro optical systems, GRD = 2 x GSD.
Makes sense, though. According to the article, the orbit is at 620km. To obtain 1.0 degrees of stereo separation would require cameras placed 10.8km apart.
Parity: What to do when the weekend comes.
Perhaps I'm not understanding how the submitter is using the term "non-military", and not to wave Uncle Sam's flag too much, but offhand I can think of more than six US RS platforms/sensors:
EOS/Terra/MODIS http://modis.gsfc.nasa.gov/
Landsat ETM+ http://landsat.gsfc.nasa.gov/
Landsat MSS (yes still going)
AVHRR http://daac.gsfc.nasa.gov/data/dataset/AVHRR/
GOES http://www.goes.noaa.gov/
ASTER http://asterweb.jpl.nasa.gov/
Not to mention US based commercial satellites:
IKONOS http://www.spaceimaging.com/
Quickbird URL:http://www.digitalglobe.com/
This isn't the first stereographic satellite that's accessible to the general public; that would be MISR - NASA's Multi-angle Imaging Spectroradiometer, built by JPL, with nine cameras pointed in different directions along its direction of travel in polar orbit, ranging from nadir (straight down) to 70 degrees in either direction. Compared to India's new high-resolution satellite, MISR seems very low resolution - 275 meters per pixel - however, it covers the entire surface of the Earth every few days and all of the data is available for free at this resolution, while India's satellite is "targeting"; it only images a particular area when it is programmed to do so. MISR is used primarily to study clouds and aerosols.
To see some 3-D images taken by MISR or some animations of its 9 cameras' views of different scenes, check out their gallery.
Langolier posted the correct answer with info not available in the FA.
Everyone who posted before this is encouraged to be a little more careful providing answers in the future. (All four that I can see are not only wrong, in the sense they don't contain the correct explanation, but also in the sense that they contain serious technical errors.)
Get cool 3D images of Grand Canyon, Yosemite, Everest, Uluru, etc.
Don't get too excited. The process of extracting 3d depth from a pair of 2d pictures is shockingly more difficult than one would initially expect. Given the 2d positions of the same point in both cameras, it is trvial to find the 3d depth, but in practice the problem of finding the corresponding points is extremely difficult. (It is called the 'correspondence problem' and can justifiably be called the holy grail of the field of Computer Vision.) For those who are truly interested, you can actually see how most of the current state of the art stereo algorithms run on a few (easy) stereo pairs here.
I do not have any arms or legs.
And a nitpick which will hopefully bring this post back on topic - the average literacy you mentioned is wrong. It is 64.8% according to the 2001 census. The number you gave was for 1991. 14 years can make a lot of difference in a country like India, even given its huge population.
The same rocket launch also put into place ham satellite for use in South Asia. There are other satellites available for personal use (AMSAT has several, including (Echo 51) but VUSat is focused on use from India and South Asia.
India doesnt receive much direct aid from the US . Indian poor do receive a large amount of money from US based evangelical groups trying to promote Christianity in India (pretty successfully too Already 2 Indian states have become Christian Majority over the last 50 years )
India keeps losing it best people to the US but now slowly more and more people are staying back and using their brains to run ISRO and DAE (department of Atomic Energy) instead of enriching the shareholders of IBM and Microsoft.
There is great emphasis on tech in India . Engineers are much more respected in society than doctors or lawyers in contrast to the US so a lot of the top brains go to Engineering.
**Life is too short to be serious**
Yes, but there are advantages to doing this via satellite as well. For example, repeat passes allow observation of subtle changes in topography due to things like subsidence from withdrawal of water or petroleum, glacier movement, tectonic and volcanic activity, etc. Basically, think about all of the applications of SAR (synthetic aperture radar, for non-remote sensers) Interferometry. There are also LIDAR satellites such as IceSAT that observe elevations with great precision along transects. There are actually quite a number of satellites up there with the capability of doing things similar to this, but generally not at this spatial resolution (2.5 m). I'm involved with a group proposing a satellite to NASA that would be used to obverve changes in water heights on floodplains and in rivers, allowing observation of ungauged rivers in remote regions as well as helping to get a handle on discharge from rivers (such as the Amazon) which are impossible to gauge along much of their length.