focal de la camera grace a un tag aruco

get_the_focal.py

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+import cv2 as cv
+import cv2.aruco as aruco
+import numpy as np
+
+# Actual width of the Aruco tag in some unit (like centimeters)
+W = 1.8
+
+# Actual distance from the camera to the object in the same unit as W
+D = 15.0
+
+# Charger une image depuis la caméra (0 pour la caméra par défaut, généralement la webcam)
+cap = cv.VideoCapture(0)
+
+# Définir le dictionnaire ArUco
+aruco_dict = aruco.getPredefinedDictionary(aruco.DICT_4X4_50)
+
+# Créer le détecteur ArUco
+parameters = aruco.DetectorParameters()
+
+detector = aruco.ArucoDetector(aruco_dict, parameters)
+
+while True:
+    # Lire une image depuis la caméra
+    ret, frame = cap.read()
+
+    # Convertir l'image en niveaux de gris
+    gray = cv.cvtColor(frame, cv.COLOR_BGR2GRAY)
+
+    # Détecter les marqueurs ArUco
+    corners, ids, rejectedImgPoints = detector.detectMarkers(gray)
+
+    # Dessiner les résultats
+    if ids is not None:
+        aruco.drawDetectedMarkers(frame, corners, ids)
+
+        for i in range(len(ids)):
+
+            # verify *at least* one ArUco marker was detected
+            if len(corners) > 0:
+                # Flatten the ArUco IDs list
+                ids = ids.flatten()
+
+                # Loop over the detected ArUCo corners
+                for (markerCorners, markerID) in zip(corners, ids):
+                    # Extract the marker corners
+                    corners = markerCorners.reshape((4, 2))
+                    (topLeft, topRight, bottomRight, bottomLeft) = corners
+
+                    # Convert each of the (x, y)-coordinate pairs to integers
+                    topRight = (int(topRight[0]), int(topRight[1]))
+                    topLeft = (int(topLeft[0]), int(topLeft[1]))
+
+                    # Calculate the apparent width in pixels
+                    P = np.sqrt((topRight[0] - topLeft[0]) ** 2 + (topRight[1] - topLeft[1]) ** 2)
+
+                    # Calculate the focal length
+                    F = (P * D) / W
+                    print(f"The focal length of the camera is: {F} pixels")
+
+    # Afficher l'image
+    cv.imshow('Frame', frame)
+
+    # Sortir de la boucle si la touche 'q' est enfoncée
+    if cv.waitKey(1) & 0xFF == ord('q'):
+        break
+
+# Libérer la capture et fermer la fenêtre
+cap.release()
+cv.destroyAllWindows()