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photo.camera.1grass

NAME

photo.camera - Interactively select and modify the imagery group camera reference file.

KEYWORDS

imagery, orthorectify

SYNOPSIS

photo.camera
photo.camera help
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

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, photo.2image, photo.2target, photo.init

AUTHOR

Mike Baba, DBA Systems, Inc.

Last changed: $Date: 2008-10-22 11:59:36 +0200 (mer, 22 ott 2008) $

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