RenZi 认字

Local OCR extraction + LLM text correction. PaddleOCR recognizes text in images, a local Ollama model corrects OCR mistakes, and an optional Flask web UI ties it together. Everything runs offline — no cloud APIs.

What It Does

RenZi takes images containing Chinese/English text and produces clean electronic text:

1. OCR — PaddleOCR (PP-OCRv5) extracts text plus per-region bounding boxes and confidence scores.
2. Visualization — renders an annotated image (green boxes) and a reconstructed text bitmap that preserves the original layout on a white canvas.
3. Correction — sends the raw OCR text to a local Ollama model (gemma3:1b by default) that fixes typos and misrecognized characters while keeping the original language and line structure.

Supported formats: .png, .jpg, .jpeg, .bmp, .tiff, .tif, .webp.

What it does not do: streaming OCR, mobile capture, cloud OCR, translation between languages.

Features

• Single image or whole-directory batch OCR
• PaddleOCR 3.6 + PP-OCRv5 server detection/recognition models
• Optional annotated image and reconstructed text bitmap PNGs
• Local Ollama LLM correction (offline, no API keys)
• Flask web UI with drag-and-drop upload and side-by-side raw/corrected text
• Unified Python API with ToolResult dataclass
• OpenAI function-calling tools schema for agent integration
• CLI with unified flags (-V -v -q --json -o)

Requirements

• Python >= 3.9
• PaddleOCR 3.6.0 + PaddlePaddle 3.0.0 (see install notes below)
• Ollama running locally with a model pulled (e.g. ollama pull gemma3:1b)
• A CJK TrueType font for bitmap rendering (auto-detected on Windows/macOS/Linux)

PaddlePaddle version pin

The known-good combination is PaddlePaddle 3.0.0 + PaddleOCR 3.6.0. Newer PaddlePaddle (3.1+) breaks old model loading via the PIR executor. Install from the Baidu mirror:

pip install paddlepaddle==3.0.0 -i https://mirror.baidu.com/pypi/simple

Installation

pip install -e .

For development dependencies:

pip install -e ".[dev]"

Ollama setup (for correction)

ollama pull gemma3:1b

Quick Start

Recognize one image and print text:

renzi photo.jpg

Batch a directory and write .txt transcripts:

renzi images/ -l ch -o transcripts/

Full pipeline with annotated image + text bitmap + corrected text file:

renzi scan.png --pipeline --bbox annotated.png --bitmap bitmap.png -o fixed.txt

Correct OCR text piped on stdin:

echo "我在吉林省、长春市" | renzi --correct -

Launch the web UI:

python -m renzi.web
# open http://127.0.0.1:8765

CLI Usage

renzi [-V] [-v] [-q] [--json] [-l LANG] [--confidence N] [-o PATH]
     [--bbox PATH] [--bitmap PATH] [--ollama-base URL] [--ollama-model NAME]
     [--timeout S] [--correct] [--pipeline] [PATH]

Flag	Meaning
-V, --version	Print version and exit
-v, --verbose	Show per-item confidence and geometry
-q, --quiet	Suppress non-essential output
--json	Output results as JSON
-l, --lang	OCR language hint (default ch)
--confidence	Minimum OCR confidence (default 0.5)
-o, --output	Output file (single) or directory (batch)
--bbox	Write annotated image PNG to this path
--bitmap	Write reconstructed text bitmap PNG to this path
--ollama-base	Ollama API base URL
--ollama-model	Ollama model name
--timeout	LLM request timeout in seconds
--correct	Correct text from stdin instead of running OCR
--pipeline	Run OCR + render + LLM correction

Python API

from renzi import extract, extract_dir, correct, pipeline, ToolResult

# Single image
result = extract(image_path="photo.jpg", lang="ch")
print(result.success)        # True
print(result.data["text"])   # raw OCR text
for it in result.data["items"]:
    print(it["text"], it["confidence"], it["bbox"])

# Directory batch with text files
result = extract_dir(directory="images/", output="transcripts/")
for filename, info in result.data.items():
    print(filename, info["text"][:50])

# Correct raw OCR text
result = correct(text="我在吉林省、长春市")
print(result.data["text"])      # corrected
print(result.data["used_llm"])  # True/False

# Full pipeline with visualizations
result = pipeline(
    image_path="scan.png",
    bbox_image="annotated.png",
    bitmap_image="bitmap.png",
    output="fixed.txt",
)

Agent Integration

from renzi.tools import TOOLS, dispatch

# Register TOOLS in your OpenAI function-calling client, then:
result = dispatch("renzi_pipeline", {
    "image_path": "scan.png",
    "bbox_image": "annotated.png",
    "bitmap_image": "bitmap.png",
})

Web UI

from renzi.web import run
run(port=8765)

Drag-and-drop upload, three-up image comparison (original / annotated / text bitmap), and side-by-side raw vs corrected text with one-click copy and re-correct.

Model Cache

PaddleOCR downloads models on first run from ModelScope into ~/.paddlex/official_models/. To bundle models offline, place them in a directory and point PADDLEX_HOME (or RENZI_MODEL_DIR) at it:

export RENZI_MODEL_DIR=/path/to/official_models
renzi photo.jpg

Development

pip install -e ".[dev]"
ruff format . && ruff check . && pytest

License

GPL-3.0