CtoW_Calibrator_aruco Class Reference

Wrapper for aruco tag camera-to-workspace extrinsic matrix calibration (M_CL) More...

Public Member Functions
def	__init__ (self, cameraMatrix, markerLength_CL, distCoeffs=np.array([0.0, 0.0, 0.0, 0.0, 0.0]), maxFrames=100, flag_vis_extrinsic=True, flag_print_MCL=True, stabilize_version=True, aruco_dict=aruco.DICT_5X5_250)
	Constructor of the CtoW_Calibrator_aruco class. More...
def	calibrate (self, rgb, depth=None)
	Process a single frame and recover transformation. More...
def	process (self, rgb, depth=None)
	Process function to calibrate extrinsic matrix from rgb and depth frames. More...
def	update (self, M_CL_new, other_infos)
	If using a running calibration, provide latest measurement and update estimate. More...
def	update_intrinsic (self, cameraMatrix)

Public Attributes
	aruco_dict
	cache_M_CL
	cache_occr
	cache_other_infos
	cameraMatrix
	corners_aruco
	detected
	distCoeffs
	flag_print_MCL
	flag_vis_ext
	frame_counter
	img_with_ext
	M_CL
	markerLength_CL
	maxFrames
	other_infos
	stabilize_version
	stable_status

Detailed Description

Wrapper for aruco tag camera-to-workspace extrinsic matrix calibration (M_CL)

The camera intrinsic matrix and distortion coefficients should generally be obtained from the camera_info topic. Currently the wrapper only supports the workspace origin being marked by one single aruco marker. In case the calibration result is unstable, the wrapper updates the M_CL based on the result of each new frame. Currently the updating method simply counts calibration results for consecutive frames and keeps the most frequent one. L2-distance is used to determine the similarity of two matrices.

The image and the camera coordinate systems are defined the same way as in the Realsense documentation.

Constructor & Destructor Documentation

__init__()

def __init__	(		self,
			cameraMatrix,
			markerLength_CL,
			distCoeffs = np.array([0.0, 0.0, 0.0, 0.0, 0.0]),
			maxFrames = 100,
			flag_vis_extrinsic = True,
			flag_print_MCL = True,
			stabilize_version = True,
			aruco_dict = aruco.DICT_5X5_250
	)

Constructor of the CtoW_Calibrator_aruco class.

Parameters

[in]	cameraMatrix	Camera intrinsic matrix
[in]	markerLength_CL	Marker side length in meters
[in]	(optional)distCoeffs	Camera distortion matrix (Default: np.array([0.0, 0.0, 0.0, 0.0, 0.0]))
[in]	(optional)maxFrames	Max frame number after which M_CL updating ceases. If None, then will always update. (Default: 5000)
[in]	(optional)flag_vis_ext	Visualize extrinsic frame on image. (Default: True)
[in]	(optional)flag_print_MCL	Print out M_CL. (Default: True)
[in]	(optional)stabilize_version	Use "stabilized" version. (Default: True) True: only first maxFrames used for calibration.
[in]	(optional)aruco_dict	Aruco dictionary. (Default: aruco.DICT_5X5_250)

Member Function Documentation

calibrate()

def calibrate	(		self,
			rgb,
			depth = None
	)

Process a single frame and recover transformation.

Parameters

[in]	rgb	Color image.
[in]	depth	Depth image [optional]. Not used in this class instance.
[out]	M_CL	The camera to workspace matrix.

process()

def process	(		self,
			rgb,
			depth = None
	)

Process function to calibrate extrinsic matrix from rgb and depth frames.

Parameters

[in]	img	(np.ndarray, (H, W, 3)) Rgb image
[in]	depth	(np.ndarray, (H, W), optional). Depth map. Not used for now. It is a placeholder for future improvement based on depth. Defaults to None
[out]	M_CL	[np.ndarray, (4, 4)] Extrinsic aruco-to-camera transformation matrix.
[out]	corners_aruco	[np.ndarray]. Detected aruco tag corners.
[out]	img_with_ext	[np.ndarray, (H, W, 3)] Color image with aruco tag coordinate. Useful for visualization. With stablize_version, if no aruco detected, will draw status. [binary]. True if aruco detected (non-stablize version) or a result has been stored (stabilize version).

update()

def update	(		self,
			M_CL_new,
			other_infos
	)

If using a running calibration, provide latest measurement and update estimate.

Parameters

[in]	M_CL_new	Latest measurement.
[in]	other_inofs	Additional information.

update_intrinsic()

def update_intrinsic	(		self,
			cameraMatrix
	)

@brief  Simply replace the original one

Member Data Documentation

aruco_dict

aruco_dict

cache_M_CL

cache_M_CL

cache_occr

cache_occr

cache_other_infos

cache_other_infos

cameraMatrix

cameraMatrix

corners_aruco

corners_aruco

detected

detected

distCoeffs

distCoeffs

flag_print_MCL

flag_print_MCL

flag_vis_ext

flag_vis_ext

frame_counter

frame_counter

img_with_ext

img_with_ext

M_CL

M_CL

markerLength_CL

markerLength_CL

maxFrames

maxFrames

other_infos

other_infos

stabilize_version

stabilize_version

stable_status

stable_status

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The documentation for this class was generated from the following file:

• /home/pvela/python/camera/camera/extrinsic/aruco.py