Crate oar_ocr 

OAR OCR

A Rust OCR library that extracts text from document images using ONNX models. Supports text detection, recognition, document orientation, and rectification.

Features

• Complete OCR pipeline from image to text
• High-level builder APIs for easy pipeline configuration
• Model adapter system for easy model swapping
• Batch processing support
• ONNX Runtime integration for fast inference

Components

• Text Detection: Find text regions in images
• Text Recognition: Convert text regions to readable text
• Layout Detection: Identify document structure elements (text blocks, titles, tables, figures)
• Document Orientation: Detect document rotation (0°, 90°, 180°, 270°)
• Document Rectification: Fix perspective distortion
• Text Line Classification: Detect text line orientation
• Seal Text Detection: Detect text in circular seals
• Formula Recognition: Recognize mathematical formulas

Modules

• core - Core traits, error handling, and batch processing
• domain - Domain types like orientation helpers and prediction models
• models - Model adapters for different OCR tasks
• oarocr - High-level OCR pipeline builders
• processors - Image processing utilities
• utils - Utility functions for images and tensors
• predictors - Task-specific predictor interfaces

Quick Start

OCR Pipeline

use oar_ocr::oarocr::{OAROCRBuilder, OAROCR};
use oar_ocr::utils::load_image;
use std::path::Path;

// Create OCR pipeline with required components
let ocr = OAROCRBuilder::new(
    "models/text_detection.onnx",
    "models/text_recognition.onnx",
    "models/character_dict.txt"
)
.with_document_image_orientation_classification("models/doc_orient.onnx")
.with_text_line_orientation_classification("models/line_orient.onnx")
.image_batch_size(4)
.region_batch_size(32)
.build()?;

// Process images
let image = load_image(Path::new("document.jpg"))?;
let results = ocr.predict(vec![image])?;

for result in results {
    for region in result.text_regions {
        if let Some(text) = region.text {
            println!("Text: {}", text);
        }
    }
}

Document Structure Analysis

use oar_ocr::oarocr::{OARStructureBuilder, OARStructure};
use std::path::Path;

// Create structure analysis pipeline
let structure = OARStructureBuilder::new("models/layout_detection.onnx")
    .with_table_classification("models/table_classification.onnx")
    .with_table_cell_detection("models/table_cell_detection.onnx", "wired")
    .with_table_structure_recognition("models/table_structure.onnx", "wired")
    .table_structure_dict_path("models/table_structure_dict.txt")
    .with_formula_recognition(
        "models/formula_recognition.onnx",
        "models/tokenizer.json",
        "pp_formulanet"
    )
    .build()?;

// Analyze document structure
let result = structure.predict("document.jpg")?;

println!("Layout elements: {}", result.layout_elements.len());
println!("Tables: {}", result.tables.len());
println!("Formulas: {}", result.formulas.len());

Modules

core

domain

models

oarocr

The OCR pipeline module.

predictors

prelude

Prelude module for convenient imports.

processors

utils

Utility functions for the OCR pipeline.

Derive Macros

ConfigValidator

Derive macro for implementing ConfigValidator trait.

TaskPredictorBuilder

Derive macro for implementing TaskPredictorBuilder trait.