Building a Fixed-Length CAPTCHA OCR Model With Multi-Head Classification

This story was originally published on HackerNoon at: https://hackernoon.com/building-a-fixed-length-captcha-ocr-model-with-multi-head-classification. How a multi-head CNN with position embeddings achieved 100% accuracy on fixed-length CAPTCHA OCR without using CRNNs or CTC loss. Check more stories related to futurism at: https://hackernoon.com/c/futurism. You can also check exclusive content about #computer-vision, #captcha-ocr, #crnn, #ctc-loss, #ocr-architecture, #multi-head-classification, #position-embeddings, #deep-learning, and more. This story was written by: @genesys. Learn more about this writer by checking @genesys's about page, and for more stories, please visit hackernoon.com. This article documents the design of a lightweight OCR system built to solve fixed-length numeric CAPTCHAs for authorized internal automation workflows. Instead of using a standard CRNN + CTC architecture, the author built a shared CNN backbone with six independent classification heads and learnable position embeddings, achieving 100% held-out accuracy with roughly 4,000 training samples while improving training stability, inference speed, and debuggability