The conventional infrared sensors suffer from trade off between sensitivity and cost. The bolometer infrared camera is low resolution and slow speed while the quantum photodetectors are bulky and expensive. In this paper, the novel low dimensional materials carbon nanotube based Schottky barrier structure non cryogenic IR detector was proposed to detect IR irradiance. In order to characterize the photodetector, a testing bench using digital microscope and precise linear stage was used to measure detector performance. The experimental results show the photodetector has negative direction response and positive direction response on right and left side respectively and the maximum photocurrent output depends on the IR irradiance gradient. The proposed measurement method will be applicable for 1D/2D nanoscale material based photodetector characterization.