Noise of LCD display systems

Abstract This paper presents the results of initial physical and psycho-physical evaluations of the noise of high resolution LCDs. Five LCDs were involved, having four different pixel structures. Spatial as well as temporal noise was physically measured with the aid of a high-performance CCD camera. Human contrast sensitivity in the presence of spatial noise was determined psycho-physically using square-wave patterns stimuli as well as square stimuli. The results demonstrate that spatial noise is the dominant noise in all LCDs, while temporal noise is insignificant and plays only a minor part. The magnitude of spatial noise of LCDs is in the range between that of CRTs with a P104 and that of CRTs with a P45. Of particular importance with respect to LCD noise is the contribution of the pixel structure to the Noise Power Spectrum, which shows up as sharp spikes at spatial frequencies beyond the LCDs' Nyquist frequency. Much more work is necessary to understand the impact of spatial noise on the diagnosis of malignant abnormalities like micro-calcifications.