Poster 63.4009. Our staff scientists explain how to accurately present colour stimuli on LCD monitors. Find out more on Wednesday.
A comparison of display technologies for accurate reproduction of colour stimuli
63.4009, Wednesday, 20 May 2015, 8:30 am - 12:30 pm, Pavilion
Session: Color Perception: Models, methods, and meaning
Caterina Ripamonti, Mark Hodgetts, Jakob Thomassen; Cambridge Research Systems Ltd
When measuring colour discrimination, it is crucial that a display device is able to reproduce colour accurately. In this study, we characterised the performance of LCD and CRT displays to reproduce a set of chromatic stimuli, and calculated the just noticeable difference between the measured and requested colour using the delta E value (DE) developed in the CIEDE2000 formula. A value of DE bigger than one represents a visible difference between the measured and requested colour. It is a commonly held belief that CRT displays have superior colour reproduction compared to LCDs; we wanted to investigate this empirically and, if true, determine a technique to improve the colour reproduction of LCDs so as to be equivalent to CRT displays. We made a series of systematic measurements which confirmed that the native performance of LCDs was not as good as the native performance of CRT displays: more than 50% of the colours reproduced by LCDs had a DE bigger than one, compared to only 15% of the colours reproduced by CRT displays. There appear to be several factors that can contribute to this inaccuracy, including (i) variations in the transmittance properties of the LCD due to changes in temperature; (ii) chromatic shift that occurs within the LCD primaries across different intensity levels; (iii) the goodness of the opto-electronic transfer function characterisation and its linearisation; (iv) the contribution of the dark light; and (iv) the colour resolution of the LCD. We developed an optimised colorimetric correction which can significantly improve the colour reproduction of a calibrated LCD to a point that its performance becomes superior to the native colour reproduction of a CRT display.