Measurements of static noise in display images

The appearance of noise on a display is an important usability issue. Sources of noise include electrical interference, display driver artifacts, resampling artifacts, transmission artifacts, compression artifacts, and any intrinsic noise artifacts produced within a display device. Issues for the severity of the noise problem include total magnitude of noise, noise spatial frequencies, proximity of the noise spatial frequencies to the spatial frequencies of the desired information content and the human-eye response to that information content, uniformity of the distribution of noise, and appearance of any visible or regular patterns in the noise. Whatever the source, an accurate method to measure noise may be required to properly assess the influence of the noise. We investigate the intricacies of using a digital camera to accurately measure noise in a static image on a flat panel display (FPD). The electro-optical transfer function of the FPD is measured. A known noise pattern is displayed and measured using the digital camera whereby the predicted noise is compared to the measured noise. Complications and limitations in the metrology will be discussed.