The basic method of infrared detection is divided into two types: passive and active. Passive infrared detection equipment in the application more; active infrared detection can be divided into single and double-sided method, in infrared detection method of heating method measured target is divided into steady and unsteady heating heating.Infrared detection instrument installation and delivery modes: fixed, portable, vehicle mounted and airborne type (helicopter loading) etc..
(1) the passive infrared detection means the measured target don’t hot up when check of infrared detection, using only measured target temperature to draw infrared detection on process of heat exchange between the measured target and environment。passive infrared detection used in the operation of device,components and scientific experiment。It no additional heat source，the basic all adoption with this way。
(2) active infrared detection of active infrared detection is the infrared detection before measured object active heating, heating source from the measured target. Way of make heat divided into a steady and non steady。infrared detection according to the different situation can be carried out in the heating process,also can be in stop heating for a certain period of time after continue their detection.

Method:
(1) one side detection:
sameMeasured Target make heating and infrared detection On same side.
(2) double-side method:
relative to the single single-sided method(the above method), double method is put on the heating measured target and infrared detection respectively in the target the positive and the negative two aspects.
(3) heating method:
1) steady state heating: steady heating mode will be measured target is heated to its internal temperature.the temperature will be reaches the homogeneous steady state, then it is placed in a lower (or higher) infrared detection of the constant temperature environment to check. This approach used for quality testing of materials, such as the analyte internal cracks, holes or debonding defects, then the measured object and environment of heat exchange in heat flow will be affected by the defects of obstacles, the corresponding outer surface can produce the change of temperature, compared with no surface defects will appear difference.
2) unsteady heating: heating of the measured target, do not need to make the internal temperature reaches the uniform or stable state.
3) as the heat into the measured object being tested evenly, heat flow into the inner speed should be decided by its internal conditions, if the internal defects, will become a baffle heat resistance, after a certain time will generate heat accumulation, will produce heat. Heat flux varies depending on the position of the defect caused by defects, direction, geometric dimensions and material thermal physical properties.