Provided by: grass-doc_6.4.3-3_all 
NAME
i.photo.camera - Interactively select and modify the imagery group camera reference file.
KEYWORDS
imagery, orthorectify
SYNOPSIS
i.photo.camera
i.photo.camera help
i.photo.camera group=name [camera=name] [--verbose] [--quiet]
Parameters:
group=name
Name of imagery group for ortho-rectification
camera=name
Name of camera reference file to use
DESCRIPTION
i.photo.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 excentricity 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, i.photo.2image, i.photo.2target, i.photo.init
AUTHOR
Mike Baba, DBA Systems, Inc.
Last changed: $Date: 2010-12-22 02:05:10 -0800 (Wed, 22 Dec 2010) $
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GRASS 6.4.3 i.photo.camera(1grass)