What is Optical Remote Sensing Imagery?

Circular 10/2015/TT-BTNMT stipulates that Optical remote sensing images are images created by capturing visible light wavelengths (0.4 - 0.76 micrometers) through satellites using optical lenses.

Optical Remote Sensing Images (Illustration)

Additionally, the Circular explains several terms related to the production of high and ultra-high-resolution optical remote sensing images for users as follows:

- Production of remote sensing images is the process of creating 1A remote sensing data, 2A remote sensing data, 3A remote sensing data, and 3B remote sensing data from level 0 remote sensing data.- Ground Resolution is the size of one pixel of an image projected on the ground.- High-resolution remote sensing images are images obtained with a ground resolution less than or equal to 20m.- Ultra-high-resolution remote sensing images are images obtained with a ground resolution less than 1m.- Digital Elevation Model (DEM) is a numerical model representing the continuous variation of surface elevation. DEM is used in image orthorectification to eliminate geometric distortions due to terrain elevation differences.- Image orthorectification is the correction of geometric distortions in the image due to the image-taking process, the influence of terrain elevation differences, and the coordinate system transformation from image space coordinates to Cartesian coordinates.- Image enhancement of remote sensing images is the adjustment of image radiometry to improve the informational capability of the image.- Level 0 remote sensing data is remote sensing data received and processed directly from satellite signals at remote sensing image reception stations without any correction process.- 1A remote sensing images are remote sensing image products corrected for Earth's curvature effects, removing errors from the image receiver and atmospheric noisy signals from level 0 remote sensing data.- 2A remote sensing images are remote sensing image products orthorectified to: the VN-2000 national coordinate reference system, the international UTM flat coordinate system, etc., using physical models and satellite orbital information.- 3A remote sensing images are remote sensing image products orthorectified to the map coordinate system, the VN-2000 national coordinate reference system, the international UTM flat coordinate system, etc., using physical models, ground control points, and the Digital Elevation Model. Spectral processing and image quality enhancement according to the scene are applied to 3A remote sensing images.- 3B remote sensing images are remote sensing images processed at the 3A level, mosaicked, and cut into map fragmentations.

For details, please see Circular 10/2015/TT-BTNMT, effective from May 12, 2015

Le Hai

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