Halcon Camera Calibration

Halcon Program

* Internal parameters of the camera:
*f: The camera's main moment, the focal length
*k: Radial distortion, that is, radial distortions, generally do not consider tangential distortion
*sx,sy: distance between adjacent pixels in the horizontal and vertical direction of the image sensor
*cx,cy: Vertical projection of the projection center in the imaging plane

* External camera parameters
* translation vector x, y, Z
* Rotation vector x, y, Z

* Perspective correction

Dev_close_window ()
Dev_update_off ()
Dev_set_draw (' margin ')
Read_image (image, ' scratch/scratch_perspective ')
Get_image_size (image, Width, Height)
Dev_open_window (0, 0, Width, Height, ' black ', windowhandle)
Set_display_font (WindowHandle, +, ' mono ', ' true ', ' false ')
Dev_display (Image)
Disp_continue_message (WindowHandle, ' black ', ' true ')

* Calibration Camera

* Calibration Board Description file
Caltabname: = ' CALTAB_30MM.DESCR '

* Initial Internal parameters
* Parameters: Focal length, thickness, width of single cell, height of single cell, graphics center x, image Center Y, graphics width, image height
Startcampar: = [0.012,0,0.0000055,0.0000055, WIDTH/2, HEIGHT/2, Width, Height]

* Create a calibration data model
Create_calib_data (' Calibration_object ', 1, 1, Calibdataid)

* Set Calibration camera parameter model
Set_calib_data_cam_param (calibdataid, 0, ' area_scan_division ', Startcampar)

* Define the calibration board description file in the calibration model
Set_calib_data_calib_object (calibdataid, 0, Caltabname)

***********************************
* Obtain the center coordinates of the mark points in the calibration board description file
* Caltab_points (Caltabname,x, Y, Z)
* Nstartpose: = []
* Nrow: = []
* Ncol: = []
***********************************

Numimages: =
For I: =1 to Numimages by 1
read_image (image, ' scratch/scratch_calib_ ' +i$ ' 02d ')
Dev_display (Image)
* Find Calibration Board area
Find_caltab (Image, Caltab, Caltabname, 3, 5)
Dev_set_color (' green ')
Dev_display (Caltab) br>
* Look for the calibration plate marker point coordinates and estimated external parameters
Find_marks_and_pose (Image, Caltab, Caltabname, startcampar,128, ten, X, 0.9, +, +, Rcoord , Ccoord, Startpose)
Dev_set_color (' red ')
Disp_circle (WindowHandle, Rcoord, Ccoord, Gen_tuple_const (| rcoord|,2.5))
Dev_set_part (0, 0, Height-1, Width-1)

* Store calibration information to the calibration board model
Set_calib_data_observ_points ( Calibdataid, 0, 0, I, Rcoord, Ccoord, ' all ', startpose)

******************************
* Combine all calibrated external and central coordinates
* Nstartpose: = [Nstartpose, Startpose]
* nrow: = [Nrow, Rcoord]
* Ncol: = [Ncol, Ccoord]
************************
ENDfor

******************************
* Calibration of all camera parameters (can not use operator set_calib_data_observ_points)
* Camera_calibration (X, Y, Z, Nrow, Ncol, Startcampar, Nstartpose, ' All ', Cameraparam, Nfinalpose, Errors)
******************************

* Calibration Camera parameters
Calibrate_cameras (Calibdataid, Error)

* Get in-camera parameters
Get_calib_data (Calibdataid, ' camera ', 0, ' params ', camparam)

* Get External camera parameters
Get_calib_data (Calibdataid, ' calib_obj_pose ', [0,1], ' pose ', posecalib)

* Convert Origin coordinates
Set_origin_pose (Startpose, -0.04, -0.03, 0.00075, pose)

* Set the calibrated image a pixel represents the actual distance
Pixeldist: = 0.00013

* Image Image generation
Gen_image_to_world_plane_map (map, Camparam, Pose, width, height, width, height, pixeldist, ' bilinear ')

Imagefiles: = [' scratch/scratch_calib_01 ', ' scratch/scratch_perspective ']
For i:= 1 to 2 by 1
Read_image (image, Imagefiles[i-1])
Dev_set_window (WindowHandle)
Dev_display (Image)


* Apply image to convert image
Map_image (image, map,imagemapped)

ENDfor

Camera_parameters.dat File Contents

#
# INTERNAL CAMERA PARAMETERS
#

# ===== generic parameter Syntax ==========================================
#
# Syntax:pargroup: <pargroupname>;
# <pargroup_description>;
#
# <name>: <shortname>: <default_value>;
# <type>: <lower_bound>: <upper_bound>;
# <description>;
#
# [<type>:: = bool| Xbool|int| Float| double| STRING]
#
# =========================================================================

##############################################################################
#
# Camera:parameter
# > Focus
# > Kappa
# > Sx
# > Sy
# > Cx
# > Cy
# > ImageWidth
# > ImageHeight
#
##############################################################################

ParGroup:Camera:Parameter;
"Internal camera Parameters";

focus:foc:0.0161703501831527;
double:0.0:;
"Focal length of the lens";

kappa:kappa:-639.990421851654;
DOUBLE::;
"Radial distortion coefficient";

sx:sx:7.40108791846177e-006;
double:0.0:;
"Width of a cell on the sensor";

sy:sy:7.4e-006;
double:0.0:;
"Height of a cell on the sensor";

cx:cx:333.895895987285;
DOUBLE::;
"X-coordinate of the Image Center";

cy:cy:244.935973115852;
DOUBLE::;
"Y-coordinate of the Image Center";

imagewidth:imgw:652;
int:1:32768;
"Width of the images";

imageheight:imgh:494;
int:1:32768;
"Height of the images";

#
# HALCON Version 12.0--Tue APR 14 22:41:15 2015
#

Camera_pose.dat File Contents

#
# 3D POSE parameters:rotation and translation
#

# Used representation Type:
F 0

# Rotation angles [deg] or Rodriguez vector:
R 3.11886998639614 358.984666972156 30.2659614074603

# translation vector (x y Z [m]):
T 0.0248668618545196 0.0133955230862179 0.401474091384729

#
# HALCON Version 12.0--Tue APR 14 22:41:15 2015

#

Halcon Camera Calibration