Experiments

A spectrometer "SpectraScan® PR 650" like the one in the figure was used to measure the spectral response of the different screens under a computer stimulus. The stimuls, generated in Matlab, consisted in a set of full-screen solid-color images with RGB parameters ranging from [1,1,1] to [0,0,0], [1,0,0] to [0,0,0], [0,1,0] to [0,0,0], and [0,0,1] to [0,0,0] with steps of 0.05. These stimulus should be a good starting point, supposing a reasonably linear system behaviour of the screens.

The screens tested were:
    IBM® Thinkpad® LCD laptop display
    Dell® Latitude® LCD laptop display
    HP® CRT display
    Sony® Trinitron® CRT display
    Panasonic® Plasma TV

With the obtained spectral power distributions, the students did the following:

• Compare the SPDs of the different intensities.
• Check the interaction of the primaries, comparing the white light with the monochromatic stimulus.
• Check the linearity of the screen primaries by normalizing the different intensities results.

Data processing

In order to obtain more information, the students processed the spectral power density results obtained using the spectrometer.
That way they obtained the XYZ values corresponding to the different intensity stimulus using the vision science principle: