Does sharpness affect the reproduction of colour images?

A psychophysical experiment was conducted to investigate the relationship between sharpness and preferred colour of images displayed on a CRT monitor screen. Blurred versions of each of four original images were generated by convolution with a low-pass Gaussian filter. Sharpened versions of these images were created through adjustment of the image power spectrum. Each test image was decomposed into a set of spatial frequency bands, defined as octaves of the pixel sampling frequency. The Fourier power spectrum was derived, then amplitudes of selected bands were adjusted to enhance the desired spatial frequencies. The experimental results indicated that: (1) sharpness was perceived to be increased when certain spatial frequency bands were enhanced; (2) weighting the frequency bands using the standard observer's contrast sensitivity function (CSF) gives better results for particular distances; and (3) preferred image colour is strongly related to image sharpness.