  We propose an efficient method for searching for color vibration pairs that
are imperceptible to the human eye based on the MacAdam ellipse, an
experimentally determined color-difference range that is indistinguishable to
the human eye. We created color pairs by selecting eight colors within the sRGB
color space specified by the ellipse, and conducted experiments to confirm the
threshold of the amplitude of color vibration amplitude at which flicker
becomes imperceptible to the human eye. The experimental results indicate a
general guideline for acceptable amplitudes for pair selection.
