read_cam

Herror ::read_cam_par ( const HTuple &CamParFile, HTuple *CamParam )

Read the internal camera parameters from text file.

::read_cam_par is used to read the internal camera parameters CamParam from a text file with name CamParFile.

The format of the text file is a (Halcon-independent) generic parameter description. Thus, arbitrary sets of parameters can be grouped together in a hierarchical way. The description of a single parameter within a parameter group consists of the following 3 lines:

   Name : Shortname : Actual value ;
    Type : Lower bound (optional) : Upper bound (optional) ;
    Description (optional) ;

The Halcon operator ::write_cam_par expects in the file CamParFile the parameter group Camera:Parameter. This parameter group consists of the 8 parameters Focus, Sx, Sy, Cx, Cy, Kappa , ImageWidth and ImageHeight. Comments are marked by a '\#' at the beginning of a line. A suitable file can look like the following:

  # INTERNAL CAMERA PARAMETERS

  ParGroup: Camera: Parameter;
      "Internal CCD-camera parameters";

  Focus:foc:      0.00806039;
      DOUBLE:0.0:;
      "Focal length of the lens [meter]";

  Sx:sx:  1.0629e-05;
      DOUBLE:0.0:;
      "Width of a cell on the CCD-chip [meter]";

  Sy:sy:  1.1e-05;
      DOUBLE:0.0:;
      "Height of a cell on the CCD-chip [meter]";

  Cx:cx:  378.236;
      DOUBLE:0.0:;
      "X-coordinate of the image center [pixel]";

  Cy:cy:  297.587;
      DOUBLE:0.0:;
      "Y-coordinate of the image center [pixel]";

  Kappa:kappa:    -2253.5;
      DOUBLE::;
      "Radial distortion coefficient [1/(meter*meter)]";

  ImageWidth:imgw:    768;
      INT:0:2048;
      "Width of the used calibration images [pixel]";

  ImageHeight:imgh:   576;
      INT:0:2048;
      "Height of the used calibration images [pixel]";

The underlying camera model is a \textbf{pinhole or telecentric camera with radial distortions}. A detailed description of these camera models can be found with description of ::write_cam_par.

Parameters

`CamParFile` (input_control)	string `->` HTuple.char *
File name of internal camera parameters.
Default value: 'campar.dat'
List of values: 'campar.dat', 'campar.initial', 'campar.final'

`CamParam` (output_control)	number-array `->` HTuple.double * / long *
Internal camera parameters.
Number of elements: 8

Example

HTuple CamParam;
// get internal camera parameters:
::read_cam_par("campar.dat",&CamParam);

Result

::read_cam_par returns H_MSG_TRUE if all parameter values are correct and the file has been read successfully. If necessary an exception handling is raised.

Possible Successors

::find_marks_and_pose, ::sim_caltab, ::create_caltab, ::disp_caltab, ::camera_calibration

Module

Camera calibration