SARSA(λ)-Based Reinforcement Learning Approach to Object Localization via SIFT in a Static Environment
Alexander Gunwhi Kim
MASDS, 2025
ZHU, YUHUA
Object localization in static visual environments remains a fundamental challenge in computer vision, particularly under conditions involving scale variations, lighting changes, and background clutter. Localizing objects using traditional detection methods alone often suffers performance degradation. To address this complexity, the following research implements a hybrid architecture comprised of traditional and modern algorithms, specifically, a reinforcement learning-based framework trained via State-Action-Reward-State-Action (SARSA) with eligibility traces (λ), ResNet-18, and feature-based matching using Scale-Invariant Feature Transform (SIFT) for conditions with background clutter. A static image from the popular children’s puzzle books, Where’s Waldo? was divided into a discrete tile-based environment, allowing the SARSA(λ) agent to navigate and identify specific objects of interest. Leveraging a reward function grounded in movement and deep feature similarity metrics extracted from ResNet-18 features and SIFT keypoints, the agent can learn an efficient policy to successfully localize an object within a tile.This dual-layer approach – combining adaptive exploration with traditional feature robustness – enabled the agent to prioritize regions most likely to contain the target, thereby reducing un-necessary search paths and improving localization reliability. Experimental results demonstrated robust localization performance across both stochastic and deterministic evaluation settings, with convergence to reliable and efficient policies using a single target. The system exhibited improved consistency in complex visual scenes where conventional detectors are prone to failure.These findings highlight the practical value of coupling adaptive learning algorithms with classical computer vision techniques to enhance the efficiency and reliability of object localization in static scenes. This approach provides a foundation for future research on hybrid models that integrate deep learning with engineered features for interpretable and generalizable visual reasoning.
2025

