Abstract：Abstract：With the thermal infrared(TIR) imaging technology，the non-contact transient process of marble rock normally impacted by a steel projectile was detected. Based on the information extraction of thermal infrared characteristics(i. e.，radiant characteristics and geometric features) from the target thermography (that just reflects part of IR radiation on the impact region，the relationships between impact-related parameters and IR-related quantities are regressively analyzed. Finally，in an additional trial，some impact-related parameters are back analyzed，such as the projectile¢s impacting velocity and kinetic energy. It was discovered that：(1) there exists a critical velocity for rock target thermography to be regular and centrally symmetrical. Within the critical velocity，the velocity of the projectile is linearly correlated to the perimeter and is quadratically correlated to the increment of TIR temperature of the target thermography；while the kinetic energy of the projectile is linearly correlated to both the area and the increment of the TIR radiant flux within the target thermography；and (2) for the quantitative back analysis to the impact-related parameters，both geometric features and radiant characteristics can be applied. It was suggested that the perimeter and the increment of the TIR radiant flux of the target thermography can be taken as the most efficient indices with the relative error of back analysis being less than 5%，while the area and the increment of TIR temperature can be taken as other auxiliary indices with error less than 15%. The results are of general meaning to the impact of other rock and solid materials；and it might extend the application of infrared remote sensing technology from static geosciences domain to dynamic mechanical domain.
