dataflow-cv 0.2.1

A data processing library for computer vision datasets

DataFlow-CV

Where Vibe Coding meets CV data. 🌊 Convert & visualize datasets. Built with the flow of Claude Code.

A data processing library for computer vision datasets, focusing on format conversion and visualization between LabelMe, COCO, and YOLO formats. Provides both a CLI and Python API.

Table of Contents

• DataFlow-CV
  • Table of Contents
  • Project Structure
  • Requirements
    • Core Dependencies
  • Quick Start
    • Installation
    • Command Line Usage
    • Python API Usage
    • CLI Reference
      • Global Options
      • Conversion Commands
      • Visualization Commands
      • Configuration Command
      • Getting Help
    • Segmentation Support
    • Running Tests
    • Examples
  • License

Project Structure

dataflow/
├── __init__.py              # Package exports and convenience functions
├── cli.py                   # Command-line interface
├── config.py                # Configuration management
├── convert/                 # Format conversion module
│   ├── __init__.py
│   ├── base.py             # Converter base class
│   ├── coco_to_yolo.py     # COCO to YOLO converter
│   └── yolo_to_coco.py     # YOLO to COCO converter
├── visualize/               # Annotation visualization module
│   ├── __init__.py
│   ├── base.py            # Visualizer base class
│   ├── yolo.py            # YOLO annotation visualizer
│   ├── coco.py            # COCO annotation visualizer
│   └── labelme.py         # LabelMe annotation visualizer
└── label/                   # Label format handlers module
    ├── __init__.py
    ├── yolo.py            # YOLO format handler
    ├── coco.py            # COCO format handler
    └── labelme.py         # LabelMe format handler
tests/
├── __init__.py
├── convert/                # Conversion tests
│   ├── __init__.py
│   ├── test_coco_to_yolo.py
│   └── test_yolo_to_coco.py
├── visualize/              # Visualization tests
│   ├── __init__.py
│   ├── test_yolo.py
│   ├── test_coco.py
│   ├── test_labelme.py
│   └── test_generic.py    # Generic visualizer tests
├── run_tests.py           # Test runner
samples/
├── __init__.py
├── example_usage.py       # Quick usage demonstration
├── cli/                   # CLI usage examples
│   ├── __init__.py
│   ├── convert/
│   │   ├── cli_coco_to_yolo.py
│   │   └── cli_yolo_to_coco.py
│   └── visualize/
│       ├── cli_yolo.py
│       ├── cli_coco.py
│       └── cli_labelme.py
└── api/                   # Python API examples
    ├── __init__.py
    ├── convert/
    │   ├── api_coco_to_yolo.py
    │   └── api_yolo_to_coco.py
    └── visualize/
        ├── api_yolo.py
        ├── api_coco.py
        └── api_labelme.py

Requirements

Core Dependencies

• Python 3.8 or higher
• Linux environment (POSIX compatible, assumes POSIX paths)
• click >= 8.1.0 – CLI framework
• numpy >= 2.0.0 – numerical operations
• opencv-python >= 4.8.0 – image processing (optional, used for some image operations)
• Pillow >= 10.0.0 – image reading (optional, used for reading image dimensions)

Quick Start

Installation

# Regular installation from source
pip install .

# Editable installation (development mode)
# Due to setuptools compatibility, use python setup.py develop (not pip install -e .)
python setup.py develop
# After editable installation, use python -m dataflow.cli instead of the dataflow command

Command Line Usage

Global options: --verbose (-v) for progress output, --overwrite to replace existing files.

# COCO to YOLO conversion (use --segmentation for polygon annotations)
dataflow convert coco2yolo annotations.json output_dir/
dataflow convert coco2yolo annotations.json output_dir/ --segmentation

# YOLO to COCO conversion
dataflow convert yolo2coco images/ labels/ classes.names output.json

# Visualize YOLO annotations (use --save to export images)
dataflow visualize yolo images/ labels/ classes.names
dataflow visualize yolo images/ labels/ classes.names --save output_dir/

# Visualize COCO annotations (use --save to export images)
dataflow visualize coco images/ annotations.json
dataflow visualize coco images/ annotations.json --save output_dir/

# Visualize LabelMe annotations (use --save to export images)
dataflow visualize labelme images/ labels/
dataflow visualize labelme images/ labels/ --save output_dir/

# Show configuration
dataflow config

# Get help
dataflow --help
dataflow convert coco2yolo --help
dataflow visualize yolo --help
dataflow visualize labelme --help

See the CLI Reference below for detailed usage.

Python API Usage

import dataflow

# COCO to YOLO conversion (pass segmentation=True for polygon annotations)
result = dataflow.coco_to_yolo("annotations.json", "output_dir")
result = dataflow.coco_to_yolo("annotations.json", "output_dir", segmentation=True)
print(f"Processed {result['images_processed']} images")

# YOLO to COCO conversion
result = dataflow.yolo_to_coco("images/", "labels/", "classes.names", "output.json")
print(f"Generated {result['annotations_processed']} annotations")

# Visualize YOLO annotations (save_dir is optional)
result = dataflow.visualize_yolo("images/", "labels/", "classes.names")
result = dataflow.visualize_yolo("images/", "labels/", "classes.names", save_dir="output_dir/")
print(f"Visualized {result['images_processed']} images")

# Visualize COCO annotations (save_dir is optional)
result = dataflow.visualize_coco("images/", "annotations.json")
result = dataflow.visualize_coco("images/", "annotations.json", save_dir="output_dir/")
print(f"Visualized {result['images_processed']} images")

# Visualize LabelMe annotations (save_dir is optional)
result = dataflow.visualize_labelme("images/", "labels/")
result = dataflow.visualize_labelme("images/", "labels/", save_dir="output_dir/")
print(f"Visualized {result['images_processed']} images")
print(f"Classes found: {result['classes_found']}")

CLI Reference

The CLI follows a hierarchical structure: dataflow <main‑task> <sub‑task> [arguments]. Global options can be placed before the main task.

Global Options

• --verbose, -v: Enable verbose output (progress information)
• --overwrite: Overwrite existing files

Conversion Commands

COCO to YOLO

dataflow convert coco2yolo COCO_JSON_PATH OUTPUT_DIR [--segmentation]

• COCO_JSON_PATH: Path to COCO JSON annotation file
• OUTPUT_DIR: Directory where labels/ and class.names will be created
• --segmentation, -s: Handle segmentation annotations (polygon format)

YOLO to COCO

dataflow convert yolo2coco IMAGE_DIR YOLO_LABELS_DIR YOLO_CLASS_PATH COCO_JSON_PATH

• IMAGE_DIR: Directory containing image files
• YOLO_LABELS_DIR: Directory containing YOLO label files (.txt)
• YOLO_CLASS_PATH: Path to YOLO class names file (e.g., class.names)
• COCO_JSON_PATH: Path to save COCO JSON file

Visualization Commands

Visualize YOLO annotations

dataflow visualize yolo IMAGE_DIR LABEL_DIR CLASS_PATH [--save SAVE_DIR]

• IMAGE_DIR: Directory containing image files
• LABEL_DIR: Directory containing YOLO label files (.txt)
• CLASS_PATH: Path to class names file (e.g., class.names)
• --save SAVE_DIR: Optional directory to save visualized images

Visualize COCO annotations

dataflow visualize coco IMAGE_DIR ANNOTATION_JSON [--save SAVE_DIR]

• IMAGE_DIR: Directory containing image files
• ANNOTATION_JSON: Path to COCO JSON annotation file
• --save SAVE_DIR: Optional directory to save visualized images

Visualize LabelMe annotations

dataflow visualize labelme IMAGE_DIR LABEL_DIR [--save SAVE_DIR]

• IMAGE_DIR: Directory containing image files
• LABEL_DIR: Directory containing LabelMe JSON files
• --save SAVE_DIR: Optional directory to save visualized images

Configuration Command

dataflow config

Shows the current configuration (file extensions, default values, CLI context).

Getting Help

dataflow --help
dataflow convert --help
dataflow convert coco2yolo --help
dataflow convert yolo2coco --help
dataflow visualize --help
dataflow visualize yolo --help
dataflow visualize coco --help
dataflow visualize labelme --help

Segmentation Support

DataFlow-CV supports both bounding box and polygon segmentation annotations across all formats:

YOLO Segmentation Format

• Detection format: class_id x_center y_center width height (normalized coordinates)
• Segmentation format: class_id x1 y1 x2 y2 ... (polygon vertices, normalized)
• YOLO segmentation files have the same .txt extension as detection files

COCO Segmentation Format

• Polygon coordinates in segmentation field (list of [x1, y1, x2, y2, ...])
• Both single-polygon and multi-polygon annotations are supported

LabelMe Segmentation Format

• Rectangle shapes (shape_type: "rectangle") for bounding box annotations
• Polygon shapes (shape_type: "polygon") for segmentation annotations
• Each JSON file contains shapes array with annotation data

Usage Examples

# Convert COCO to YOLO with segmentation annotations
dataflow convert coco2yolo annotations.json output_dir/ --segmentation

# Visualize YOLO annotations in strict segmentation mode (only polygons)
dataflow visualize yolo images/ labels/ classes.names --segmentation

# Visualize COCO annotations in strict segmentation mode
dataflow visualize coco images/ annotations.json --segmentation

# Visualize LabelMe annotations in strict segmentation mode (only polygons)
dataflow visualize labelme images/ labels/ --segmentation

Python API

# Convert COCO to YOLO with segmentation
result = dataflow.coco_to_yolo("annotations.json", "output_dir", segmentation=True)

# Visualize in strict segmentation mode
result = dataflow.visualize_yolo("images/", "labels/", "classes.names", segmentation=True)
result = dataflow.visualize_labelme("images/", "labels/", segmentation=True)

Notes

• Without the --segmentation flag, both bounding boxes and polygons are processed automatically
• With --segmentation flag, only valid polygon annotations are processed (strict mode)
• YOLO segmentation format requires at least 3 points (6 coordinates)
• COCO segmentation polygons are automatically converted to YOLO normalized coordinates
• LabelMe format supports both rectangle (shape_type: "rectangle") and polygon (shape_type: "polygon") shapes
• In segmentation mode, LabelMe visualizer rejects rectangle shapes and only accepts polygon shapes

Running Tests

# Run all tests
python tests/run_tests.py

# Run specific test
python tests/run_tests.py --test TestCocoToYoloConverter

# With verbose output
python tests/run_tests.py -v

Examples

Check the samples/ directory for detailed usage examples:

• samples/cli/convert/ - CLI conversion examples
• samples/cli/visualize/ - CLI visualization examples
• samples/api/convert/ - Python API conversion examples
• samples/api/visualize/ - Python API visualization examples

License

MIT License © 2026 zjykzj