Spectral characteristics of the phantom array visibility

This study investigates the influence of spectral distribution on the visibility of the phantom array effect. Using light-emitting diode (LED) modules combining nine different narrowband wavelengths, we evaluated the visibility of the phantom array for various spectral distributions. An integrating sphere was used to provide spatially uniform luminance for each light source during the experiment. We found that visibility increased as peak wavelengths approached the red-orange spectrum (624 nm) and decreased towards the blue spectrum. Statistical analysis revealed higher threshold frequencies for amber and red-orange LEDs than for violet, royal blue and blue LEDs, suggesting that the response time of L and S cones may play a key role in the phantom array effect. These findings imply that the spectral distribution of the light source must be considered in the visibility model of the phantom array effect. Future research should explore individual differences in visual sensitivity to develop accurate phantom array visibility models.