1. A method comprising: capturing a signal from a shielded infrared sensor that is substantially blocked from receiving infrared radiation from a scene; capturing a signal from an unshielded infrared sensor configured to receive the infrared radiation from the scene; determining an average thermographic offset reference for the shielded and unshielded infrared sensors based on the captured signal of the shielded infrared sensor; and determining an absolute radiometric value for the scene based on the average thermographic offset reference and the captured signal of the unshielded infrared sensor.