ArucoMultipleMarkers.py

from imutils.video import VideoStream
import imutils
import time
import cv2
import numpy as np

# ---------------------------------------------------------------------------------------
#       < User Inputs >
cam = 0  # camera to read from (1 for USB-connected)
markerLength = 100  # mm (marker dimensions, square side length)
# ---------------------------------------------------------------------------------------

# load camera calibration data
mtx = np.loadtxt('Cam_Matrix.txt')
dist = np.loadtxt('Dist_Coeff.txt')

# define the names of each possible ArUco tag that OpenCV supports
ARUCO_DICT = {
    "DICT_4X4_50": cv2.aruco.DICT_4X4_50,
    "DICT_4X4_100": cv2.aruco.DICT_4X4_100,
    "DICT_4X4_250": cv2.aruco.DICT_4X4_250,
    "DICT_4X4_1000": cv2.aruco.DICT_4X4_1000,
    "DICT_5X5_50": cv2.aruco.DICT_5X5_50,
    "DICT_5X5_100": cv2.aruco.DICT_5X5_100,
    "DICT_5X5_250": cv2.aruco.DICT_5X5_250,
    "DICT_5X5_1000": cv2.aruco.DICT_5X5_1000,
    "DICT_6X6_50": cv2.aruco.DICT_6X6_50,
    "DICT_6X6_100": cv2.aruco.DICT_6X6_100,
    "DICT_6X6_250": cv2.aruco.DICT_6X6_250,
    "DICT_6X6_1000": cv2.aruco.DICT_6X6_1000,
    "DICT_7X7_50": cv2.aruco.DICT_7X7_50,
    "DICT_7X7_100": cv2.aruco.DICT_7X7_100,
    "DICT_7X7_250": cv2.aruco.DICT_7X7_250,
    "DICT_7X7_1000": cv2.aruco.DICT_7X7_1000,
    "DICT_ARUCO_ORIGINAL": cv2.aruco.DICT_ARUCO_ORIGINAL,
    "DICT_APRILTAG_16h5": cv2.aruco.DICT_APRILTAG_16h5,
    "DICT_APRILTAG_25h9": cv2.aruco.DICT_APRILTAG_25h9,
    "DICT_APRILTAG_36h10": cv2.aruco.DICT_APRILTAG_36h10,
    "DICT_APRILTAG_36h11": cv2.aruco.DICT_APRILTAG_36h11
}

# load the chosen ArUCo dictionary and grab the ArUCo parameters
arucoDict = cv2.aruco.Dictionary_get(ARUCO_DICT["DICT_4X4_100"])
arucoParams = cv2.aruco.DetectorParameters_create()

# initialize the video stream
vs = VideoStream(src=cam).start()
time.sleep(2.0)

# compute new camera matrix for calibration purposes
frame = vs.read()
h, w = frame.shape[:2]
newcameramtx, roi = cv2.getOptimalNewCameraMatrix(mtx, dist, (w, h), 1, (w, h))

# loop over the frames from the video stream
while True:
    # capturing a single frame
    frame = vs.read()
    # undistorted with calibration data
    frame = cv2.undistort(frame, mtx, dist, None, newcameramtx)
    # setting max width to 600 pixels
    frame = imutils.resize(frame, width=600)
    # converting to greyscale
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    # detecting ArUco markers in processed frame
    (corners, ids, rejected) = cv2.aruco.detectMarkers(gray,
                                                       arucoDict, parameters=arucoParams)
    if ids is None:
        ids = []

    # verify that at least one ArUco marker was detected
    if len(ids) > 0:

        # flatten the ArUco IDs list
        ids = ids.flatten()
        # print(list(zip(corners[0], ids)))

        # loop over the detected ArUCo corners
        for (markerCorner, markerID) in zip(corners, ids):
            # capturing rotation and translation vectors for detected marker
            rvec, tvec, objPts = cv2.aruco.estimatePoseSingleMarkers(markerCorner, markerLength,
                                                                     newcameramtx, dist)
            cv2.aruco.drawAxis(frame, newcameramtx, dist, rvec, tvec, 40)

            # extract the marker corners (which are always returned
            # in top-left, top-right, bottom-right, and bottom-left
            # order)
            corners = markerCorner.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]))
            bottomRight = (int(bottomRight[0]), int(bottomRight[1]))
            bottomLeft = (int(bottomLeft[0]), int(bottomLeft[1]))
            topLeft = (int(topLeft[0]), int(topLeft[1]))

            # draw the bounding box of the ArUCo detection
            cv2.line(frame, topLeft, topRight, (0, 0, 255), 2)
            cv2.line(frame, topRight, bottomRight, (0, 0, 255), 2)
            cv2.line(frame, bottomRight, bottomLeft, (0, 0, 255), 2)
            cv2.line(frame, bottomLeft, topLeft, (0, 0, 255), 2)

            # draw the ArUco marker ID on the frame
            ID_str = 'ID: ' + str(markerID)
            cv2.putText(frame, ID_str,
                        (topLeft[0], topLeft[1] - 30),
                        cv2.FONT_HERSHEY_SIMPLEX,
                        0.5, (0, 255, 0), 2)

            # draw the distance to the marker on the frame
            distance = np.sqrt(np.square(tvec[0][0][0]) + np.square(tvec[0][0][1]) + np.square(tvec[0][0][2]))
            distance = int(distance)
            Dis_str = 'Distance: ' + str(distance) + ' mm'
            cv2.putText(frame, Dis_str,
                        (topLeft[0], topLeft[1] - 15),
                        cv2.FONT_HERSHEY_SIMPLEX,
                        0.5, (0, 0, 0), 2)

    # show the output frame
    cv2.imshow("Frame", frame)
    key = cv2.waitKey(1) & 0xFF

    # if the `q` key was pressed, break from the loop
    if key == ord("q"):
        break

# cleanup
cv2.destroyAllWindows()
vs.stop()