Sabtu, 12 April 2008

Sensor Spotlight: ALOS Prism

While there is a lot of interest in "high resolution satellite/airborne data" out there in the blogosphere, I haven't seen much discussion on the merits of individual sensors. Hence, I thought it would be interesting to focus a post now and then on individual satellite and airborne sensors.

One satellite sensor that has been getting a lot of attention lately is ALOS PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping). ALOS was launched on January 24th, 2006 from the Tanegashima Space Center in Japan. While the focus of this post is on the PRISM sensor, the satellite also hosts two other on-board sensors: the AVNIR-2 and PALSAR sensors.

The unique aspect of the PRISM sensor is that it has it is a pushbroom sensor, with three optical systems for capturing forward, nadir, and backward imagery. At nadir the spatial resolution is 2.5 meters. The complete specs are here. For stereo photogrammetry applications, the key factoid about PRISM is that it collects stereo imagery, so it is possible to extract 3D terrain and feature information.

RESTEC, the Remote Sensing Technology Center of Japan, also has a wealth of information on ALOS and ALOS PRISM. In addition to all the background information, it also has some useful sample data. Here is a sample PRISM image. RESTEC has also developed an ALOS Viewer application that can be used to open images from the various ALOS sensors and perform basic operations like measuring distance and, in the case of stereo PRISM data, manually measuring building height.

Lastly, one thing to note is the the ALOS PRISM rigorous sensor model is supported in LPS 9.2. If this is a data type you need, please look into getting your hands on the new version!

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