1photo.camera(1) Grass User's Manual photo.camera(1)
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9 photo.camera creates or modifies entries in a camera reference file.
10 For ortho-photo rectification, a camera reference file is required for
11 computation of scanned image to photo-coordinate transformation parame‐
12 ters. There are two coordinate systems: The image coordinate system
13 (in pixels) and the photo coordinate system (in milli-meters). The
14 inner orientation establishes a relation between the pixels and the
15 image coordinates with help of fiducial marks.
16 The first prompt in the program will ask you for the name of the camera
18 reference file to be created or modified. You may create a new camera
19 reference file by entering a new name, or modify an existing camera
20 reference file by entering the name of an existing camera file.
21 After entering the camera file name, following menu is displayed:
23 Please provide the following information
25 CAMERA NAME: camera name______
28 CAMERA IDENTIFICATION: identification___
29 CALIBRATED FOCAL LENGTH mm.:_________________
30 POINT OF SYMMETRY (X) mm.:_________________
31 POINT OF SYMMETRY (Y) mm.:_________________
32 MAXIMUM NUMBER OF FIDUCIALS:_________________
33 AFTER COMPLETING ALL ANSWERS, HIT <ESC> TO CONTINUE
34 (OR <Ctrl-C> TO CANCEL)
35 The camera name and identification describe the camera reference file.
36 The calibrated focal length and the point of symmetry are used in com‐
37 puting the photo-to-target transformation parameters. These values
38 should be entered from the camera calibration report (usually available
39 from the photograph supplier).
40 This example is the camera Zeiss LMK9 265-002A belonging to the Hel‐
42 lenic Military Geographical Survey (HMGS) and calibrated in December
43 1985
44 The photo coordinate system origin is the so-called calibrated princi‐
46 pal point (PP, Principal Point of Symmetry) which is in the center of
47 the image. The origin of the axes is at the intersection of the radii
48 traced from the fiducial marks. In the ideal case of no deviations in
49 the camera (see camera calibration certificate) the center is the ori‐
50 gin and the values are 0 for both X and Y of Point of Symmetry. But
51 usually the principal point does not fall on the intersection of the
52 radii at the center of the picture. This excentricity is usually of the
53 order of a few micrometers.
54 You are then asked to enter the X and Y photo coordinates of each fidu‐
56 cial as follows. These fiducials (or reseau) marks are index marks
57 imaged on film which serve as reference photo coordinate system. The
58 maximum number of fiducials will determine the number of fiducial or
59 reseau coordinate pairs to be entered below. The origin is the center
60 of the image (or the point of symmetry) and X and Y are left-right and
61 up-down. The order is up to the user, but must be kept consistent
62 throughout the rectification process.
63 On this screen you should enter the fiducial or reseau photo-coordi‐
65 nates as given in the camera calibration report. The X, and Y coordi‐
66 nates are in milli-meters from the principle point.
67 Please provide the following information
69 Fid# FID ID X Y
70 1__ _____ 0.0___ 0.0___
71 2__ _____ 0.0___ 0.0___
72 3__ _____ 0.0___ 0.0___
73 4__ _____ 0.0___ 0.0___
74 5__ _____ 0.0___ 0.0___
75 6__ _____ 0.0___ 0.0___
76 7__ _____ 0.0___ 0.0___
77 8__ _____ 0.0___ 0.0___
78 9__ _____ 0.0___ 0.0___
79 10_ _____ 0.0___ 0.0___
80 next: end__
81 AFTER COMPLETING ALL ANSWERS, HIT <ESC> TO CONTINUE
82 (OR <Ctrl-C> TO CANCEL)
83 The input display is repeated until the number of MAXIMUM FIDUCIALS is
84 reached.
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87 i.ortho.photo, photo.2image, photo.2target, photo.init
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90 Mike Baba, DBA Systems, Inc.
91 Last changed: $Date: 2006-09-22 16:57:14 +0200 (Fri, 22 Sep 2006) $
93GRASS 6.3.0 photo.camera(1)