Perceptual Non-Uniformity (PNU) Index

Computing & Wireless : Computing Methods

Available for licensing


  • Alan Bovik, Ph.D. , Electrical and Computer Engineering
  • Todd Goodall , Electrical and Computer Engineering

Background/unmet need

Thermal imagers require a perceptual method of measuring non-uniformity on the fly. An accurate measurement of non-uniformity will allow thermal imagers to accurately self-calibrate. The Perceptual Non-Uniformity (PNU) Index significantly improves on accuracy and precision in detecting the magnitude of non-uniformity present in an infrared image compared to the current state of the art. The PNU Index not only provides this accurate measurement, but is also robust to additive white noise.

Invention Description

The perceptual non-uniformity (PNU) index allows measurement of additive non-uniformity noise produced in infrared images or videos as a result of manufacturing differences across the sensors in thermal imagers. The purpose of this invention is to provide real-time feedback to the thermal imager about the level of non-uniformity noise present in the image or video to allow scene-based calibration.


  • Fast
  • Requires little training
  • High measurement accuracy


  • Written in Python
  • Can be used for quality control
  • Real-time applications

Market potential/applications

The method was developed as part of infrared image/video quality assessment research, and as such, can have many quality-based applications. IR manufacturers can use this invention for quality control.

Development Stage

Lab/bench prototype

IP Status

  • 1 U.S. patent application filed