Unbiased Gradient Estimation for Event Binning via Functional Backpropagation

Fuente: arXiv
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Autori principali: Chen, Jinze, Zhai, Wei, Han, Han, Ma, Tiankai, Cao, Yang, Li, Bin, Zha, Zheng-Jun
Natura: Preprint
Pubblicazione: 2026
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author Chen, Jinze
Zhai, Wei
Han, Han
Ma, Tiankai
Cao, Yang
Li, Bin
Zha, Zheng-Jun
author_facet Chen, Jinze
Zhai, Wei
Han, Han
Ma, Tiankai
Cao, Yang
Li, Bin
Zha, Zheng-Jun
contents Event-based vision encodes dynamic scenes as asynchronous spatio-temporal spikes called events. To leverage conventional image processing pipelines, events are typically binned into frames. However, binning functions are discontinuous, which truncates gradients at the frame level and forces most event-based algorithms to rely solely on frame-based features. Attempts to directly learn from raw events avoid this restriction but instead suffer from biased gradient estimation due to the discontinuities of the binning operation, ultimately limiting their learning efficiency. To address this challenge, we propose a novel framework for unbiased gradient estimation of arbitrary binning functions by synthesizing weak derivatives during backpropagation while keeping the forward output unchanged. The key idea is to exploit integration by parts: lifting the target functions to functionals yields an integral form of the derivative of the binning function during backpropagation, where the cotangent function naturally arises. By reconstructing this cotangent function from the sampled cotangent vector, we compute weak derivatives that provably match long-range finite differences of both smooth and non-smooth targets. Experimentally, our method improves simple optimization-based egomotion estimation with 3.2\% lower RMS error and 1.57$\times$ faster convergence. On complex downstream tasks, we achieve 9.4\% lower EPE in self-supervised optical flow, and 5.1\% lower RMS error in SLAM, demonstrating broad benefits for event-based visual perception. Source code can be found at https://github.com/chjz1024/EventFBP.
format Preprint
id arxiv_https___arxiv_org_abs_2602_12590
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Unbiased Gradient Estimation for Event Binning via Functional Backpropagation
Chen, Jinze
Zhai, Wei
Han, Han
Ma, Tiankai
Cao, Yang
Li, Bin
Zha, Zheng-Jun
Computer Vision and Pattern Recognition
Event-based vision encodes dynamic scenes as asynchronous spatio-temporal spikes called events. To leverage conventional image processing pipelines, events are typically binned into frames. However, binning functions are discontinuous, which truncates gradients at the frame level and forces most event-based algorithms to rely solely on frame-based features. Attempts to directly learn from raw events avoid this restriction but instead suffer from biased gradient estimation due to the discontinuities of the binning operation, ultimately limiting their learning efficiency. To address this challenge, we propose a novel framework for unbiased gradient estimation of arbitrary binning functions by synthesizing weak derivatives during backpropagation while keeping the forward output unchanged. The key idea is to exploit integration by parts: lifting the target functions to functionals yields an integral form of the derivative of the binning function during backpropagation, where the cotangent function naturally arises. By reconstructing this cotangent function from the sampled cotangent vector, we compute weak derivatives that provably match long-range finite differences of both smooth and non-smooth targets. Experimentally, our method improves simple optimization-based egomotion estimation with 3.2\% lower RMS error and 1.57$\times$ faster convergence. On complex downstream tasks, we achieve 9.4\% lower EPE in self-supervised optical flow, and 5.1\% lower RMS error in SLAM, demonstrating broad benefits for event-based visual perception. Source code can be found at https://github.com/chjz1024/EventFBP.
title Unbiased Gradient Estimation for Event Binning via Functional Backpropagation
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2602.12590