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Title: ReLU, Sparseness, and the Encoding of Optic Flow in Neural Networks

Journal Article · · Sensors
DOI: https://doi.org/10.3390/s24237453 · OSTI ID:2505116
ORCiD logo [1];  [2]; ORCiD logo [3]
  1. Colby College, Waterville, ME (United States)
  2. Colby College, Waterville, ME (United States); Microsoft Corporation, Redmond, WA (United States)
  3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Accurate self-motion estimation is critical for various navigational tasks in mobile robotics. Optic flow provides a means to estimate self-motion using a camera sensor and is particularly valuable in GPS- and radio-denied environments. The present study investigates the influence of different activation functions—ReLU, leaky ReLU, GELU, and Mish—on the accuracy, robustness, and encoding properties of convolutional neural networks (CNNs) and multi-layer perceptrons (MLPs) trained to estimate self-motion from optic flow. Our results demonstrate that networks with ReLU and leaky ReLU activation functions not only achieved superior accuracy in self-motion estimation from novel optic flow patterns but also exhibited greater robustness under challenging conditions. The advantages offered by ReLU and leaky ReLU may stem from their ability to induce sparser representations than GELU and Mish do. Our work characterizes the encoding of optic flow in neural networks and highlights how the sparseness induced by ReLU may enhance robust and accurate self-motion estimation from optic flow.

Research Organization:
Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA)
Grant/Contract Number:
NA0003525
OSTI ID:
2505116
Report Number(s):
SAND--2025-00767J
Journal Information:
Sensors, Journal Name: Sensors Journal Issue: 23 Vol. 24; ISSN 1424-8220
Publisher:
MDPI AGCopyright Statement
Country of Publication:
United States
Language:
English

References (31)

R‐ADVANCE: Rapid Adaptive Prediction for Vision‐based Autonomous Navigation, Control, and Evasion journal September 2017
Estimating heading from optic flow: Comparing deep learning network and human performance journal October 2022
Array programming with NumPy journal September 2020
SciPy 1.0: fundamental algorithms for scientific computing in Python journal February 2020
Enhancing optical-flow-based control by learning visual appearance cues for flying robots journal January 2021
Estimating curvilinear self-motion from optic flow with a biologically inspired neural system* journal June 2022
The interpretation of a moving retinal image
  • Longuet-Higgins, Hugh Christopher; Prazdny, K.
  • Proceedings of the Royal Society of London. Series B. Biological Sciences, Vol. 208, Issue 1173, p. 385-397 https://doi.org/10.1098/rspb.1980.0057
journal July 1980
A ConvNet for the 2020s conference June 2022
Delving Deep into Rectifiers: Surpassing Human-Level Performance on ImageNet Classification conference December 2015
Visual-lidar odometry and mapping: low-drift, robust, and fast conference May 2015
CNN-based Ego-Motion Estimation for Fast MAV Maneuvers conference May 2021
Learning to Fly by MySelf: A Self-Supervised CNN-Based Approach for Autonomous Navigation conference October 2018
Exploring Representation Learning With CNNs for Frame-to-Frame Ego-Motion Estimation journal January 2016
LS-VO: Learning Dense Optical Subspace for Robust Visual Odometry Estimation journal July 2018
Robust Coding Over Noisy Overcomplete Channels journal February 2007
Sparse Coding and Decorrelation in Primary Visual Cortex During Natural Vision journal February 2000
Neuronal Population Coding of Movement Direction journal September 1986
Decoding Visual Inputs From Multiple Neurons in the Human Temporal Lobe journal October 2007
Honeybees as a Model for the Study of Visually Guided Flight, Navigation, and Biologically Inspired Robotics journal April 2011
A motion pooling model of visually guided navigation explains human behavior in the presence of independently moving objects journal January 2012
Possible role for recurrent interactions between expansion and contraction cells in MSTd during self-motion perception in dynamic environments journal June 2017
Optic-Flow Based Slope Estimation for Autonomous Landing journal December 2013
Competitive Dynamics in MSTd: A Mechanism for Robust Heading Perception Based on Optic Flow journal June 2016
Neural correlates of sparse coding and dimensionality reduction journal June 2019
3D Visual Response Properties of MSTd Emerge from an Efficient, Sparse Population Code journal August 2016
seaborn: statistical data visualization journal April 2021
The Perception of Visual Surfaces journal July 1950
Modeling heading and path perception from optic flow in the case of independently moving objects journal January 2013
Accuracy optimized neural networks do not effectively model optic flow tuning in brain area MSTd journal September 2024
Ego-Motion Estimation Using Recurrent Convolutional Neural Networks through Optical Flow Learning journal January 2021
Human heading judgments in the presence of moving objects journal January 1996