ChromaGazer: Unobtrusive Visual Modulation using Imperceptible Color Vibration for Visual Guidance

TL;DR

ChromaGazer tackles the challenge of unobtrusive visual guidance in VR/AR by leveraging imperceptible color vibration, where color pairs alternating above the critical color fusion frequency around $25$ Hz are perceived as a single color. The authors identify a distinct intermediate perceptual state between fusion and flicker and determine perceptual thresholds using a MacAdam-ellipse–based color-vibration framework, then apply these parameters to guide gaze on natural images with eye-tracking. Through two experiments, they demonstrate that carefully tuned color vibration can steer attention to Regions of Interest while preserving scene naturalness, enabling unobtrusive guidance that reduces cognitive load relative to explicit cues. They also discuss practical applications (advertising, picture books, task assistance) and outline limitations and future work, including hue/brightness effects, saliency modeling, neuroscience, and deployment across display environments. Overall, ChromaGazer provides a principled approach to perceptual tuning for gaze optimization in immersive environments, with implications for more seamless user experiences in VR/AR contexts.

Abstract

Visual guidance (VG) is critical for directing user attention in virtual and augmented reality applications. However, conventional methods using explicit visual annotations can obstruct visibility and increase cognitive load. To address this, we propose an unobtrusive VG technique based on color vibration, a phenomenon in which rapidly alternating colors at frequencies above 25 Hz are perceived as a single intermediate color. We hypothesize that an intermediate perceptual state exists between complete color fusion and perceptual flicker, where colors appear subtly different from a uniform color without conscious perception of flicker. To investigate this, we conducted two experiments. First, we determined the thresholds between complete fusion, the intermediate state, and perceptual flicker by varying the amplitude of color vibration pairs in a user study. Second, we applied these threshold parameters to modulate regions in natural images and evaluated their effectiveness in guiding users' gaze using eye-tracking data. Our results show that color vibration can subtly guide gaze while minimizing cognitive load, providing a novel approach for unobtrusive VG in VR and AR applications.

Figures (9)

• Figure 1: Experimental setup for Sec. \ref{['sec:eval-thresh']}.
• Figure 2: (a) Image pairs to be presented during color vibration adjustment ($r=50$) for each participant. The image pair at $w=0.7$ has a stronger yellow saturation than the image pair at $w=0.5$. (b) Color vibration adjustment. The participant adjusts the weight $w$ so that the color appears perceptually the same as the gray of the left half.
• Figure 3: An example of the color vibration image pairs presented in the experiment of Sec. \ref{['sec:eval-thresh']}. In the central visual field condition, we applied color vibration at a specified $r$ and $d$ to a single circle. In the peripheral visual field condition, we applied color vibration at the specified $r$ and $d$ to one of four circles. Participants were asked to indicate whether they perceived the color vibration.
• Figure 4: Experimental results showing the thresholds $r_{\mathrm{th}}$ for the Awareness condition (participants perceive the color as "different from a solid color") at 50% and 75% probability, and the thresholds for the Discomfort condition (participants perceive an "obvious flicker"), for each display position of the image circle. The image circle sizes are $d = 60~\mathrm{mm}, 80~\mathrm{mm}, 100~\mathrm{mm}$. Note that Boundary represents the boundary between central and peripheral vision, and Blind spot corresponds to the blind spot in human vision.
• Figure 5: Examples of images presented in Sec. \ref{['sec:eval-guidance']}. (a) The unmodulated image, i.e., the original image. (b) Images with color vibration applied to the ROI. (c) The "explicit" VG image with the ROI circled.