pywayne-cv-tools

name	pywayne-cv-tools
description	OpenCV YAML file read/write utilities. Use when working with pywayne.cv.tools module to read OpenCV FileStorage YAML files with support for nested structures, numpy arrays, basic types, and lists. Handles cv2.FileNode parsing including Map, Seq, and matrix nodes.

Pywayne CV YAML I/O

This module provides utilities for reading and writing OpenCV cv2.FileStorage YAML files.

Quick Start

from pywayne.cv.tools import read_cv_yaml, write_cv_yaml
import numpy as np

# Write to YAML file
data = {
    "camera_name": "test_camera",
    "image_width": 1920,
    "image_height": 1080,
    "calibration_matrix": np.eye(3)
}
write_cv_yaml('config.yaml', data)

# Read from YAML file
data = read_cv_yaml('config.yaml')
print(data)

Supported Data Types

Type	Handling
int, float, str	Written directly
np.ndarray	Written using fs.write()
list	Written using FileNode_SEQ
dict	Written using FileNode_MAP
None	Skipped

Reading Files

from pywayne.cv.tools import read_cv_yaml

# Read YAML file (returns dict or None on error)
data = read_cv_yaml('camera_config.yaml')
if data:
    print(data['camera_name'])
    print(data['image_width'])

Notes:

• Handles nested structures recursively
• Returns None if file cannot be opened
• Uses wayne_print for error messages (red/yellow colors)
• Supports both FileNode_MAP and FileNode_SEQ for dictionaries and lists
• Matrix nodes read using .mat() method

Writing Files

from pywayne.cv.tools import write_cv_yaml

# Write data to YAML file
data = {
    "matrix": np.eye(3),
    "vector": [1, 2, 3]
}
success = write_cv_yaml('config.yaml', data)

if success:
    print("Write successful")

Notes:

• Returns True on success, False on error
• Handles lists with empty key convention for OpenCV
• Supports unnamed sequences using empty key string
• Skips None values during write

Requirements

• cv2 (OpenCV) - For FileStorage operations
• numpy - For numpy array handling
• pywayne.tools - For wayne_print logging

API Reference

Function	Description
read_cv_yaml(path)	Read OpenCV YAML file, returns dict or None
write_cv_yaml(path, data)	Write dict to OpenCV YAML file, returns bool

File Structure Handling

The module handles OpenCV's cv2.FileNode types:

Node Type	Handling
Map	Uses .keys() method (requires callable)
Seq	Uses element iteration with recursive parsing
Matrix	Uses .mat() method
Int/Float/String	Uses .real(), .int(), .string() methods