1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
|
Camera calibration
==================
Any camera device have to be calibrated to compensate its optical distorsion.
The first step to calibrate a [ArUcoCamera](/argaze/#argaze.ArUcoMarkers.ArUcoCamera) is to create an [ArUcoBoard](/argaze/#argaze.ArUcoMarkers.ArUcoBoard) like in the code below:
``` python
from argaze.ArUcoMarkers import ArUcoMarkersDictionary, ArUcoBoard
# Create ArUco dictionary
aruco_dictionary = ArUcoMarkersDictionary.ArUcoMarkersDictionary('DICT_APRILTAG_16h5')
# Create an ArUco board of 7 columns and 5 rows with 5 cm squares with 3cm ArUco markers inside
aruco_board = ArUcoBoard.ArUcoBoard(7, 5, 5, 3, aruco_dictionary)
# Export ArUco board with 300 dpi resolution
aruco_board.save('./calibration_board.png', 300)
```
Then, the calibration process needs to make many different captures of an [ArUcoBoard](/argaze/#argaze.ArUcoMarkers.ArUcoBoard) through the camera and then, pass them to an [ArUcoDetector](/argaze/#argaze.ArUcoMarkers.ArUcoDetector.ArUcoDetector) instance.
The sample of code below shows how to detect board corners into camera frames, store detected corners then process them to build calibration data and, finally, save it into a JSON file:
``` python
from argaze.ArUcoMarkers import ArUcoMarkersDictionary, ArUcoCamera, ArUcoBoard, ArUcoDetector
# Create ArUco dictionary
aruco_dictionary = ArUcoMarkersDictionary.ArUcoMarkersDictionary('DICT_APRILTAG_16h5')
# Create ArUco camera
aruco_camera = ArUcoCamera.ArUcoCamera(dimensions=(1920, 1080))
# Create ArUco board of 7 columns and 5 rows with 5 cm squares with 3cm aruco markers inside
# Note: This board is the one expected during further board tracking
expected_aruco_board = ArUcoBoard.ArUcoBoard(7, 5, 5, 3, aruco_dictionary)
# Create ArUco detector
aruco_detector = ArUcoDetector.ArUcoDetector(dictionary=aruco_dictionary, marker_size=3)
# Capture frames from a live Full HD video stream (1920x1080)
while video_stream.is_alive():
frame = video_stream.read()
# Detect all board corners in frame
aruco_detector.detect_board(frame, expected_aruco_board, expected_aruco_board.markers_number)
# If board corners are detected
if aruco_detector.board_corners_number > 0:
# Draw board corners to show that board tracking succeeded
aruco_detector.draw_board(frame)
# Append tracked board data for further calibration processing
aruco_camera.store_calibration_data(aruco_detector.board_corners, aruco_detector.board_corners_identifier)
# Start camera calibration processing for Full HD image resolution
print('Calibrating camera...')
aruco_camera.calibrate(expected_aruco_board)
# Print camera calibration data
print('Calibration succeeded!')
print(f'RMS:{aruco_camera.rms}')
print(f'Camera matrix:{aruco_camera.K}')
print(f'Distortion coefficients:{aruco_camera.D}')
# Save camera calibration data
aruco_camera.to_json('calibration.json')
```
Then, the camera calibration data are loaded to compensate optical distorsion during [ArUcoMarkers](/argaze/#argaze.ArUcoMarkers.ArUcoMarker) detection:
``` python
from argaze.ArUcoMarkers import ArUcoCamera
# Load camera calibration data
aruco_camera = ArUcoCamera.ArUcoCamera.from_json('./calibration.json')
```
|
