Mindee: docTR

Surya is an OCR and document layout analysis toolkit developed by Vikram Paruchuri and distributed via Mindee, first released in January 2024 under the GPL-3.0 license. It supports text recognition across more than 90 languages, document layout detection, reading order prediction, table recognition, and equation detection, providing a comprehensive set of tools for extracting structured information from document images.Surya is designed to operate without cloud API dependencies, running fully on local hardware with support for CPU and GPU inference. It is commonly used for digitizing scanned documents, extracting text from PDFs with complex layouts, and building automated document processing pipelines.

TrOCR (Transformer-based Optical Character Recognition) is an end-to-end OCR model released in September 2021 by Microsoft Research. It departs from the traditional two-stage OCR pipeline — which typically combines a CNN-based feature extractor with an RNN-based sequence decoder — by using a pure Transformer architecture composed of a pretrained image Transformer encoder and a pretrained text Transformer decoder, an approach that later became standardized as the VisionEncoderDecoder pattern in Hugging Face Transformers.TrOCR takes a cropped text line image as input and produces a sequence of output tokens, supporting printed, handwritten, and scene text recognition. The model is designed for use downstream of a separate text detection stage — TrOCR recognizes text in pre-cropped regions rather than detecting text locations in a full page. Microsoft released three size variants: TrOCR-small (62M parameters, DeiT-small encoder + MiniLM decoder), TrOCR-base (334M parameters, BEiT-base encoder + RoBERTa-large decoder), and TrOCR-large (558M parameters, BEiT-large encoder + RoBERTa-large decoder). Pretrained and fine-tuned checkpoints are available for printed text (on SROIE), handwritten text (on IAM), and scene text (on the standard scene text benchmarks) under the MIT license, distributed through the Microsoft unilm repository and Hugging Face. At release, TrOCR achieved state-of-the-art results across all three benchmark categories, and the model continues to be used as a baseline for handwritten text recognition.

GLM-OCR is a multimodal OCR model for complex document understanding, built on the GLM-V encoder-decoder architecture by Zhipu AI. The model combines a 0.4B-parameter CogViT visual encoder pre-trained on large-scale image-text data, a lightweight cross-modal connector with efficient token downsampling, and a 0.5B-parameter GLM language decoder, totaling 0.9B parameters. To address the inefficiency of standard autoregressive decoding in deterministic OCR tasks, GLM-OCR introduces a Multi-Token Prediction (MTP) mechanism that predicts multiple tokens per step, significantly improving decoding throughput while keeping memory overhead low through shared parameters. Training proceeds through four stages: visual encoder pretraining with MIM, CLIP, and distillation objectives; vision-language pretraining on document parsing, grounding, and VQA data; supervised fine-tuning on curated OCR datasets covering text, formula, table, and key information extraction; and full-task reinforcement learning to improve accuracy and structural consistency.At the system level, GLM-OCR adopts a two-stage pipeline in which PP-DocLayout-V3 first performs layout analysis, followed by parallel region-level recognition. This design enables robust handling of diverse document layouts including tables, formulas, and multi-column text. The model supports document parsing and targeted recognition tasks, producing structured outputs in Markdown, JSON, and LaTeX formats across more than 100 languages. On the OmniDocBench V1.5 benchmark, GLM-OCR scores 94.62, and achieves 94.0 on OCRBench and 96.5 on UniMERNet for formula recognition.

Google Vision OCR, released as part of the Cloud Vision API’s general availability in February 2016, is a proprietary Google Cloud service for extracting text from images and documents. It supports common formats like JPEG, PNG, GIF, TIFF, and PDF, and provides two main modes: TEXT_DETECTION for short snippets and scene text, and DOCUMENT_TEXT_DETECTION for dense documents, which returns structured layout information with bounding boxes.While not an LLM (so it has no token context window or parameter count), the service performs OCR across printed text and some handwriting. It outputs detected text along with positional metadata, making it useful for digitizing scanned files, receipts, forms, and signs. However, complex layouts like tables often require downstream processing. Accessible via REST and RPC APIs, with client libraries in major languages, Google Vision OCR is widely used for document processing pipelines, archival, and accessibility applications.

Florence-2, introduced by Microsoft Research at CVPR 2024, is an open-source vision-language foundation model designed to unify diverse computer vision tasks within a single sequence-to-sequence framework. Unlike traditional models that specialize in specific tasks, Florence-2 accepts both images and text prompts and outputs text for tasks such as captioning, object detection, segmentation, OCR, and region-based grounding. It comes in two sizes—Florence-2-base (~230M parameters) and Florence-2-large (~770M parameters)—and is trained on FLD-5B, a large dataset of ~126M images with ~5.4B annotations.The model demonstrates strong zero-shot and fine-tuned performance, often rivaling larger vision-language systems while remaining lightweight and efficient. Released under the MIT license, all weights are publicly available, making it accessible for fine-tuning and deployment in applications like VQA, content tagging, accessibility, and research. Florence-2’s compact design, versatility, and openness position it as a practical alternative to larger proprietary multimodal models.