Signed-weight projection for robust in-sensor computing neural classifiers under amplitude-dependent noise and stuck-at faults
摘要
In-sensor computing (ISC) monolithically integrates photodetection and neural-network inference on the same focal plane, avoiding analog-to-digital conversion and off-chip data movement. Despite its unrivalled latency and energy benefits, ISC remains limited by the fragility of analog weights. Amplitude-dependent drift, random-telegraph noise, and irreversible stuck-at faults can each trigger abrupt accuracy collapse. We introduce a training-free hardening strategy—signed-weight projection—that clips every weight to a symmetric range, enforcing a zero-mean distribution without changing network topology or requiring retraining. First-order perturbation analysis shows that the resulting balanced weights self-cancel the mean shift produced by multiplicative noise, while the magnitude cap limits the worst-case impact of saturated faults. Hardware measurements on a