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A Deep Learning Approach for American Sign Language Alphabet Recognition

Bahadkar, Siddhant Sanjay (2025) A Deep Learning Approach for American Sign Language Alphabet Recognition. Masters thesis, Dublin, National College of Ireland.

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Abstract

Communicating with individuals who are deaf or have speech impairments remains difficult when sign language cannot be assumed to be widely known. This project proposes a fully automated, real-time American Sign Language (ASL) recognition pipeline, leveraging deep learning and computer vision. Our objective was to identify and benchmark several advanced convolutional neural network (CNN) architectures for distinguishing the full ASL alphabet, and then to embed the most accurate model into a live recognition stream driven by a webcam and MediaPipe hand tracking. This study trained and fine-tuned a suite of pre-trained models like VGG16, ResNet50, InceptionV3, DenseNet201, and MobileNetV2 alongside a custom CNN on a balanced ASL dataset of 27 handshape classes. Each architecture was rigorously quantified with classification metrics and real-time latency. VGG16 emerged as the top performer, achieving an overall validation accuracy of ≈93.2%, with stable inference speeds during live demonstrations. Visual diagnostics and confusion matrices revealed both the discriminative strengths and shortcomings of the various designs. These findings affirm that transfer learning, when coupled with fine-tuned parameter adaptation, yields proficient ASL handshape recognisers. Embedded into a low-latency detection framework, such classifiers have the potential to broaden the reach of assistive technologies for deaf and hard-of-hearing users. Future works will transition to continuous sign tracking, gesture sequences, and multilingual lexicon support.

Item Type: Thesis (Masters)
Supervisors:
Name
Email
Milosavljevic, Vladimir
UNSPECIFIED
Uncontrolled Keywords: American Sign Language (ASL); Alphabet Recognition; Deep Learning; Convolutional Neural Networks (CNNs); Transfer Learning; MediaPipe; Real-Time Testing; VGG16; ResNet50; DenseNet201; InceptionV3; MoobileNetV2; Computer Vision
Subjects: Q Science > QA Mathematics > Electronic computers. Computer science
T Technology > T Technology (General) > Information Technology > Electronic computers. Computer science
Q Science > QH Natural history > QH301 Biology > Methods of research. Technique. Experimental biology > Data processing. Bioinformatics > Artificial intelligence > Computer vision
Q Science > Q Science (General) > Self-organizing systems. Conscious automata > Artificial intelligence > Computer vision
P Language and Literature > P Philology. Linguistics > Semiotics > Language. Linguistic theory > Gesture. Sign language
Divisions: School of Computing > Master of Science in Data Analytics
Depositing User: Ciara O'Brien
Date Deposited: 24 Aug 2026 15:40
Last Modified: 24 Aug 2026 15:40
URI: https://norma.ncirl.ie/id/eprint/9617

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