From 0b678204dbc733d199ddde1fc5dcaeb76c5af8a3 Mon Sep 17 00:00:00 2001
From: Théo de la Hogue
Date: Tue, 29 Nov 2022 12:13:00 +0100
Subject: Separating calibration data from ArUcoCamera class.

---
 src/argaze/ArUcoMarkers/ArUcoCamera.py | 83 +++++++++++++---------------------
 1 file changed, 32 insertions(+), 51 deletions(-)

diff --git a/src/argaze/ArUcoMarkers/ArUcoCamera.py b/src/argaze/ArUcoMarkers/ArUcoCamera.py
index 06438ac..dd254d2 100644
--- a/src/argaze/ArUcoMarkers/ArUcoCamera.py
+++ b/src/argaze/ArUcoMarkers/ArUcoCamera.py
@@ -1,5 +1,7 @@
 #!/usr/bin/env python
 
+from dataclasses import dataclass, field
+
 import json
 import numpy
 import cv2.aruco as aruco
@@ -10,73 +12,52 @@ K0 = numpy.array([[1., 0., 0.], [0., 1., 0.], [0., 0., 0.]])
 D0 = numpy.array([0.0, 0.0, 0.0, 0.0, 0.0])
 """Define default camera distorsion coefficients vector."""
 
-class ArUcoCamera():
-    """Handle optical calibration data with:
-        - camera intrinsic parameters matrix as K (focal lengths and principal point),
-        - camera distorsion coefficients vector as D."""
-
-    def __init__(self):
-        """Define optical parameters."""
+@dataclass(frozen=True)
+class CalibrationData():
+    """Define optical camera calibration data."""
 
-        self.__rms = 0
+    rms: float = field(default=0)
+    """Root Mean Square error of calibration."""
 
-        self.__dimensions = [0, 0] 
+    dimensions: numpy.ndarray = field(default=numpy.array([0, 0]))
+    """Frame dimensions in pixels from which the calibration have been done."""
 
-        self.__K = K0
-        self.__D = D0
+    K: numpy.array = field(default=K0)
+    """Intrinsic parameters matrix (focal lengths and principal point)."""
 
-        # define calibration data
-        self.__corners_set_number = 0
-        self.__corners_set = []
-        self.__corners_set_ids = []
+    D: numpy.array = field(default=D0)
+    """Distorsion coefficients vector."""
 
-    def __del__(self):
-        pass
+    def __init__(self, **kwargs):
+        
+        self.__dict__.update(kwargs)
 
-    def load_calibration_file(self, camera_calibration_filepath):
+    @classmethod
+    def from_json(self, json_filepath):
         """Load optical parameters from .json file."""
 
-        with open(camera_calibration_filepath) as calibration_file:
+        with open(json_filepath) as calibration_file:
 
-            calibration_data = json.load(calibration_file)
+            return CalibrationData(**json.load(calibration_file))
 
-            self.__rms = calibration_data['rms']
-            self.__dimensions = calibration_data['dimensions']
-            self.__K = numpy.array(calibration_data['camera matrix'])
-            self.__D = numpy.array(calibration_data['distortion coefficients'])
-
-    def save_calibration_file(self, camera_calibration_filepath):
+    def to_json(self, json_filepath):
         """Save optical parameters into .json file."""
 
-        calibration_data = {'rms': self.__rms, 'dimensions': self.__dimensions, 'camera matrix': self.__K.tolist(), 'distortion coefficients': self.__D.tolist()}
-
-        with open(camera_calibration_filepath, 'w', encoding='utf-8') as calibration_file:
+        with open(json_filepath, 'w', encoding='utf-8') as calibration_file:
 
-            json.dump(calibration_data, calibration_file, ensure_ascii=False, indent=4)
+            json.dump(self, calibration_file, ensure_ascii=False, indent=4)
 
-    @property
-    def rms(self) -> float:
-        """Get Root Mean Square (rms) error."""
+class ArUcoCamera(CalibrationData):
+    """Handle camera calibration process."""
 
-        return self.__rms
-
-    @property
-    def dimensions(self) -> list:
-        """Get camera frame dimensions in pixels from which the calibration have been done."""
+    def __init__(self, **kwargs):
+        
+        super().__init__(**kwargs)
 
-        return self.__dimensions
-
-    @property
-    def K(self) -> numpy.array:
-        """Get camera intrinsic parameters matrix."""
-
-        return self.__K
-
-    @property
-    def D(self) -> numpy.array:
-        """Get camera distorsion coefficients vector."""
-
-        return self.__D
+        # Calibration data
+        self.__corners_set_number = 0
+        self.__corners_set = []
+        self.__corners_set_ids = []
 
     def calibrate(self, board, frame_width, frame_height):
         """Retrieve camera K and D from stored calibration data."""
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