i.ortho.camera(1grass)

NAME
i.ortho.camera - Select and modify the imagery group camera reference file.

KEYWORDS
imagery, orthorectify

SYNOPSIS
i.ortho.camera
i.ortho.camera --help
i.ortho.camera [group=name] camera=name [name=string] [id=string] [clf=float] [pp=east,north] [fid=east,north[,east,north,...]] [--help] [--verbose] [--quiet] [--ui]

  Flags:

--help
    Print usage summary

--verbose
    Verbose module output

--quiet
    Quiet module output

--ui
    Force launching GUI dialog

  Parameters:

group=name
    Name of imagery group for ortho-rectification

camera=name [required]
    Name of camera reference file
    Name of input file

name=string
    Camera name

id=string
    Camera id

clf=float
    Calibrated focal length

pp=east,north
    Principal point coordinates
    Coordinates

fid=east,north[,east,north,...]
    Fiducial coordinates
    Coordinates

DESCRIPTION
i.ortho.camera creates or modifies entries in a camera reference file. For ortho-photo rectification, a camera reference file is required for computation of scanned image to photo-coordinate transformation parameters. There are two coordinate systems: The image coordinate system (in pixels) and the photo coordinate system (in milli-meters). The inner orientation establishes a relation between the pixels and the image coordinates with help of fiducial marks.

The first prompt in the program will ask you for the name of the camera reference file to be created or modified. You may create a new camera reference file by entering a new name, or modify an existing camera reference file by entering the name of an existing camera file.

After entering the camera file name, following menu is displayed:

Please provide the following information

    CAMERA NAME:               camera name______
    CAMERA IDENTIFICATION:     identification___
    CALIBRATED FOCAL LENGTH mm.:_________________
    POINT OF SYMMETRY (X)   mm.:_________________
    POINT OF SYMMETRY (Y)   mm.:_________________
    MAXIMUM NUMBER OF FIDUCIALS:_________________
   AFTER COMPLETING ALL ANSWERS, HIT <ESC> TO CONTINUE
               (OR <Ctrl-C> TO CANCEL)

The camera name and identification describe the camera reference file. The calibrated focal length and the point of symmetry are used in computing the photo-to-target transformation parameters. These values should be entered from the camera calibration report (usually available from the photograph supplier).

This example is the camera Zeiss LMK9 265-002A belonging to the Hellenic Military Geographical Survey (HMGS) and calibrated in December 1985

The photo coordinate system origin is the so-called calibrated principal point (PP, Principal Point of Symmetry) which is in the center of the image. The origin of the axes is at the intersection of the radii traced from the fiducial marks. In the ideal case of no deviations in the camera (see camera calibration certificate) the center is the origin and the values are 0 for both X and Y of Point of Symmetry. But usually the principal point does not fall on the intersection of the radii at the center of the picture. This eccentricity is usually of the order of a few micrometers.

You are then asked to enter the X and Y photo coordinates of each fiducial as follows. These fiducials (or reseau) marks are index marks imaged on film which serve as reference photo coordinate system. The maximum number of fiducials will determine the number of fiducial or reseau coordinate pairs to be entered below. The origin is the center of the image (or the point of symmetry) and X and Y are left-right and up-down. The order is up to the user, but must be kept consistent throughout the rectification process.

On this screen you should enter the fiducial or reseau photo-coordinates as given in the camera calibration report. The X, and Y coordinates are in milli-meters from the principle point.

Please provide the following information

    Fid#    FID ID          X          Y
    1__    _____        0.0___    0.0___
    2__    _____        0.0___    0.0___
    3__    _____        0.0___    0.0___
    4__    _____        0.0___    0.0___
    5__    _____        0.0___    0.0___
    6__    _____        0.0___    0.0___
    7__    _____        0.0___    0.0___
    8__    _____        0.0___    0.0___
    9__    _____        0.0___    0.0___
    10_    _____        0.0___    0.0___
             next:  end__
     AFTER COMPLETING ALL ANSWERS, HIT <ESC> TO CONTINUE
                    (OR <Ctrl-C> TO CANCEL)

The input display is repeated until the number of MAXIMUM FIDUCIALS is reached.

SEE ALSO
i.ortho.photo, g.gui.photo2image, g.gui.image2target, i.ortho.init

AUTHOR
Mike Baba, DBA Systems, Inc.

SOURCE CODE

Available at: i.ortho.camera source code (history)

Accessed: Thursday Oct 30 22:18:45 2025

Main index | Imagery index | Topics index | Keywords index | Graphical index | Full index

© 2003-2025 GRASS Development Team, GRASS GIS 8.4.1 Reference Manual