Investigating the Impact of Input Resolution on Object Detection Performance Using EfficientDet for Signature Detection in Document Images
Keywords:
signature detection, object detection, EfficientDet, BiFPN, input resolution, document image analysisAbstract
Automated signature detection is a critical component of intelligent document processing systems, supporting document authentication and fraud detection. This paper presents a controlled empirical investigation of the effect of input resolution on handwritten signature detection using EfficientDet-D0. Three resolutions—512×512, 640×640, and 768×768—were evaluated under identical training conditions on a self-collected corpus of 1,000 annotated document images. Detection performance, measured by mAP@0.5, follows a non-monotonic trend: it improves from 0.9000 at 512×512 to a peak of 0.9261 at 640×640, then declines slightly to 0.9233 at 768×768, even though the 768×768 configuration achieves the lowest validation loss. We attribute this pattern to interacting effects of BiFPN feature granularity, anchor-scale alignment, and optimization complexity, and we discuss the scope and limitations of a single-architecture, single-run study. The results indicate that input resolution is a domain-specific hyperparameter that should be empirically tuned rather than inherited from benchmark conventions.
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