I have been working on performing camera calibration using ChAruCo boards.
Following the code here (my commented version is shown below), it appears that only every other image is used when performing the camera calibration - due to the decimator.
What could be a reason for this? Other than to save processing power, which seems unnecessary since this step is only performed once.
def read_chessboards(chessboard_images):
# Charuco base pose estimation.
print("POSE ESTIMATION STARTS:")
# Declare lists to store corner locations and IDs
allCorners = []
allIds = []
decimator = 0
# SUB PIXEL CORNER DETECTION CRITERION
criteria = (cv2.TERM_CRITERIA_EPS + cv2.TERM_CRITERIA_MAX_ITER, 100, 0.00001)
# for each of the chessboard images
for im in chessboard_images:
print("=> Processing image {0}".format(im))
frame = cv2.imread(im) # read current image into frame variable
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) # convert to grayscale
corners, ids, rejectedImgPoints = cv2.aruco.detectMarkers(gray, ARUCO_DICT) # detect markers present in image
# if there are any markers detected
if len(corners) > 0:
# SUB PIXEL DETECTION
for corner in corners:
# refine corner locations
# TODO: check if this works
cv2.cornerSubPix(gray, corner,
winSize=(3, 3),
zeroZone=(-1, -1),
criteria=criteria)
# interpolate position of ChArUco board corners.
res2 = cv2.aruco.interpolateCornersCharuco(corners, ids, gray, board)
print(f'Charuco corners at: {res2}')
# if 3+ corners are detected, add to allCorners list for every other image
if res2[1] is not None and res2[2] is not None and len(res2[1]) > 3 and decimator % 1 == 0:
allCorners.append(res2[1])
allIds.append(res2[2])
# why only every other chessboard image?
decimator += 1
imsize = gray.shape
return allCorners, allIds, imsize
