Remote sensing image data

Image data are images obtained by imaging systems on satellites or airplanes, mostly remote sensing image data. Each pixel of image data has a value, which means that the sensor detects the electromagnetic radiation intensity of the target on the ground area corresponding to the pixel, also called brightness value and gray value. Supermap

Supported image data formats are: *. img，*。 tif，*。 tiff，*。 bmp，*。 jpg，*。 png，*。 gif，*。 Primitive, * Sid, wait.

Computer records data in binary, so its quantization level is divided in binary, that is, 2n. If each pixel is recorded with n bits, its gray value can range from 0 to 2n- 1, for example, 8-bit data takes 28=256 gray levels (its value is 0 ~ 255); If you specify 1 bit to record each pixel, then its gray value is only 0 and 1, which is the so-called binary image. If a color system is used to record an image, according to the principle of colorimetry, any color can be composed of red (R), green (G) and blue (B) in a proper proportion. If 8-bit RGB color coordinate system is used to record pixels, 224= 16772 16 different RGB combinations can be recorded. Wherein, if the brightness values of RGB are 0, 0 and 0 respectively, black pixels are generated; If RGB is 255, 255, 255, white pixels will be produced, and if the brightness values of RGB are equal, gray scale effect will be produced.

Imaging mode of remote sensing image

The imaging methods of remote sensing image data mainly include aerial photography, aerial scanning and microwave radar;

Aerial photography: photographic imaging is a technology to obtain images of objects through imaging equipment. Traditional photographic imaging relies on optical lens and photosensitive film placed on the focal plane to record the image of the object. Digital photography records the image of an object with digital signals by placing photosensitive elements on the focal plane and by optical/electrical conversion. Detection bands include: near ultraviolet band, visible band and infrared band.

Aerial scanning: scanning imaging is to sample the target object point by point and line by line with the help of detection elements and scanning mirrors, and obtain the electromagnetic radiation characteristic information of the target object to form an image of a certain band. The detection bands include ultraviolet, infrared, visible light and microwave bands.

Microwave radar: The working wavelength of microwave imaging radar is in 1mm- 1m microwave band. Because microwave radar is an active sensor, it has its own energy, and Weibo has the ability to penetrate clouds, which is all-weather and all-weather. In urban remote sensing, this imaging method is of great significance for identifying microwave-sensitive targets. At the same time, microwave has a certain penetration ability to ice, snow, forest and soil, and it is also of special significance to ocean remote sensing. The detection band includes microwave band and infrared band.

Remote sensing space platform

Space remote sensing image satellites are divided into three series: land satellites, ocean satellites and meteorological satellites. Details of each type are as follows:

Landsat series: The purpose of this satellite is to detect land resources. This satellite is characterized by multi-band scanning, and the ground resolution is 5-30m. At present, the main land resources satellites are Landsat, SPOT, IRS, CBERS, JERS, IKONOS and QuickBird.

Ocean Satellite Series: The world ocean satellites include ocean color satellites, ocean terrain satellites and ocean environment satellites. At present, the main marine satellites are: Canadian radar satellite, European ERS satellite and American Seasat satellite.

Meteorological satellite series: Meteorological satellites are widely used in national economy and military fields, and can continuously, rapidly and widely detect global atmospheric changes. The orbits of meteorological satellites are divided into low orbit and high orbit, which are repeated in short periods and have strong real-time performance. At present, the main meteorological satellites are NOAA satellite in the United States, GMS meteorological satellite in Japan and FY meteorological satellite in China.