Vis sammendrag
Eye-tracking data are expensive to collect, requiring specialized hardware and controlled laboratory conditions, and difficult to share due to privacy regulations, which together limit the quantity and diversity of gaze data available for research. We address this with two complementary denoising diffusion probabilistic models (DDPMs) for unconditional generation of continuous eye-gaze dynamics from the same visual-search eye-tracking dataset. Both use an identical FiLM-conditioned one-dimensional U-Net with self-attention (19.35\,M parameters) trained on data from visual searches performed by 28 participants, with sliding-window samples 8\,s in length. The first model generates raw two-dimensional gaze-position sequences directly, and the second generates the corresponding two-component velocity sequences; the two formulations use representation-specific preprocessing, training configurations, data partitions, and evaluation protocols. Each model is evaluated across three independent training seeds over its own fixed train/validation split; seed-aggregated metrics are reported as mean\,$\pm$\,SD while single-reference-run analyses are identified separately. The position-space model achieves a mean Jensen-Shannon (JS) divergence of $0.016\pm0.004$ over nine kinematic features, with the highest feature-wise mean below $0.030$, fixation duration within 2\% of real data, and a Fr\'echet Gaze Distance more than an order of magnitude below statistical and Markovian baselines. Under a Train-on-Synthetic-Test-on-Real protocol, synthetic-only training achieves $R^2=0.66\pm0.02$, corresponding to 82.7\% of the real-data $R^2$ point estimate. The velocity-space model achieves a mean JS divergence of $0.0065$ across velocity-component, speed, log-speed, and turning angle distributions, with a maximum of $0.015\pm0.005$. Reconstructed path length is less accurately reproduced ($0.21\pm0.02$ versus $0.03\pm0.01$ in position space), although the validation protocols differ. Taken together, the two representations indicate that unconditional diffusion reliably captures the local kinematic structure of human gaze motion, velocity-component marginals, scalar speed, and short-range temporal and directional statistics, while integrated, long-range structure such as saccade counts and cumulative path geometry remains the principal target for future stimulus- or participant-conditioned models.