A method for extracting the characteristic of small targets was presented in the ground based sky from long wave infrared images.

This article describes the optical design of a wide-angle lens suitable for long-wave infrared (LWIR) earth sensor whose operating wavelength range is 10 to 16 microns, and full angle of view is up to 135 degrees, having an uncooled staring focal plane array.

The choice of type, the determination of basic parameters, and the design and manufacture of long-wave infrared (LWIR) objectives with both a wide field angle of view and a small F-number are introduced in detail.

Using the method of wavelet edge detection in the field of radiation temperature measure,two displacement formulae of inflexion wavelength justice are derived out through the relation of radiation energy,temperature and wavelenght and a new theory of the infrared wavelength thermometry is put forward.