ASTM E1213 Minimum Resolvable Temperature Difference for Thermal Imaging Systems

Scope:

ASTM E1213 test method covers the characteristics of thermal imaging systems by determining their minimum resolvable temperature difference. It determines their applications and specifications. The method proceeds with the quality check and the testing of the chemical composition of materials.  The results obtained from this method help in quality control, research, and performance evaluation of thermal imaging systems and helps check their effectiveness and resolution capability. 

Procedure:

In ASTM E1213, a differential blackbody is used with a standard four-bar target to establish one blackbody isothermal temperature for the set of bars and another blackbody isothermal temperature for the set of conjugate bars, which are generated by the regions between the bars. The target is imaged onto a thermal imaging system’s monochrome video monitor, which is seen by an observer. The temperature difference between the bars and their conjugates is gradually increased until the observer can differentiate the four bars, starting at zero. The MRTD is the crucial temperature difference. At the crucial temperature difference that determines the MRTD, the geographical distribution of the temperature of each target is detected remotely. 

Video 01: Thermal Imaging vs Infrared Thermometer

Specimen detail:

Specimen size should be as per the requirements. In this ASTM E1213 test, the four periodic bars of aspect ratio (width: height) 1:7 are taken.

Result:

Calculate the spatial frequency, F, of the test charts by using the formula where 

F= spatial frequency,

D = distance from target to the thermal imaging system.

Conclusion:

The ASTM E1213 test method is specifically important for the quality assurance and durability check of thermal imaging systems. Their effectiveness and resolution capability are determined.