`yolo-to-json`: Convert YOLO to JSON Format¶

The yolo-to-json command converts YOLO format annotations to a more readable and portable JSON format. This can be useful for data examination, sharing, or as an intermediate format for further processing.

Usage¶

m3-download yolo-to-json INPUT_DIR NAMES_FILE WIDTH HEIGHT OUTPUT_FILE [--round]

Parameters¶

INPUT_DIR: Directory containing YOLO annotation text files
NAMES_FILE: File containing class names, one per line
WIDTH: Image width (for scaling normalized YOLO coordinates)
HEIGHT: Image height (for scaling normalized YOLO coordinates)
OUTPUT_FILE: Path to save the output JSON file
--round: (Optional) Round the scaled coordinates to the nearest whole number

Output Format¶

The JSON output follows this structure:

{
  "/absolute/path/to/annotation1.txt": [
    {
      "concept": "class_name",
      "x": 100,
      "y": 200,
      "width": 50,
      "height": 40
    },
    ...
  ],
  "/absolute/path/to/annotation2.txt": [
    ...
  ]
}

How It Works¶

The command reads all YOLO annotation files (.txt) in the input directory
For each annotation, it converts:
- Class indices to human-readable class names using the provided names file
- Normalized coordinates to absolute pixel coordinates using the provided dimensions
- Center-based coordinates (YOLO) to top-left coordinates (traditional)
All annotations are compiled into a single JSON file

Coordinate Precision

Use the --round flag when you need integer coordinates (e.g., for displaying in pixel-based applications). Omit it when you need to preserve the exact floating-point precision (e.g., for mathematical analysis).

Examples¶

Basic conversion with integer coordinates:

m3-download yolo-to-json yolo_annotations/ yolo.names 1920 1080 localizations.json --round

Preserving floating point precision:

m3-download yolo-to-json yolo_annotations/ yolo.names 1920 1080 localizations.json

yolo-to-json: Convert YOLO to JSON Format¶