Annotation of /trunk/src/compiler/fields/dnorm-format.txt

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Revision 110 - (view) (download)
Original Path: trunk/src/compiler/image-info/dnorm-format.txt

1 :	glk	107	The ASCII lines in the header end with '\n'.
2 :
3 :			First line should be the magic:
4 :			NRRD0004
5 :
6 :			Rest of header will be a sequence of plain text lines, terminated by
7 :			an empty line ('\n' alone). Some header lines give per-array
8 :			information, some give per-axis information.
9 :
10 :
11 :			============================================================
12 :			The basic fields that should be there are:
13 :
14 :			----------------
15 :			type: <string>
16 :
17 :			Gives the type of the scalar values in the array. Current values are:
18 :			signed char
19 :			unsigned char
20 :			short
21 :			unsigned short
22 :			int
23 :			unsigned int
24 :			long long int
25 :			unsigned long long int
26 :			float
27 :			double
28 :
29 :			----------------
30 :			dimension: <int>
31 :
32 :			Gives the dimension of the array. Must be greater than 0. Current
33 :			code has a #define that limits the value to <= 16. The per-axis fields
34 :			will have this many pieces of information.
35 :
36 :			----------------
37 :			encoding: <string>
38 :
39 :			How scalar values are encoded on disk. Currently, should only see
40 :			"encoding: raw".
41 :
42 :			----------------
43 :			endian: <string>
44 :
45 :			Endian-ness of raw values saved on disk. Possibilities are:
46 :			little
47 :			big
48 :
49 :			----------------
50 :			space dimension: <int>
51 :
52 :			Gives the dimension of the world-space in which the array or oriented
53 :			(For now we're not allowing the named spaces that are given with the
54 :			"space: " field). The points and vectors given by "space origin"
55 :			and "space directions" will have this many coefficients, so this
56 :			field has to precede "space origin" and "space directions".
57 :
58 :			----------------
59 :			space origin: (<float1>,<float2>,...,<floatN>)
60 :
61 :			Gives the location of the center of the first sample (with index
62 :			space coordinates (0,0,0,...,0). The number of coefficients
63 :			separated by commas and bounded by parens (with optional whitespace
64 :			throughout) is given by the "space dimension" field. Each coefficient
65 :			is a floating point value (of the sort produced by printf("%g", val))
66 :
67 :			============================================================
68 :			The per-axis fields that should be there are as follows. The ordering
69 :			of these fields is always *fast* to *slow*, and the number of pieces
70 :			of information is always equal to the image dimension.
71 :
72 :			----------------
73 :			sizes: <int1> <int2> ... <intD>
74 :
75 :			The number of samples along each axis. Each integer value must be >= 0.
76 :
77 :			----------------
78 :			kinds: <string1> <string2> ... <stringD>
79 :
80 :			The kind of information represented by the samples along each axis. The
81 :			possible values are:
82 :
83 :			2-vector
84 :			3-vector
85 :			4-vector
86 :			2D-symmetric-matrix
87 :			2D-matrix
88 :			3D-symmetric-matrix
89 :			3D-matrix
90 :			space
91 :
92 :			The "space" kind is for a typical axis of the image, with samples that
93 :			subtend some region of the spatial domain of the image. All the other
94 :			kinds are the sequence of scalar values that compose a non-scalar
95 :			image value (vectors and tensors). We are currently not allowing the
96 :			"measurement frame" field that identifies the coordinate system in
97 :			which these are measured relative to the image orientation, so nothing
98 :			should be assumed about the space in which these coefficients are
99 :			measured:
100 :
101 :			2D-symmetric-matrix: Mxx Mxy Myy
102 :			2D-matrix: Mxx Mxy Myx Myy
103 :			3D-symmetric-matrix: Mxx Mxy Mxz Myy Myz Mzz
104 :			3D-matrix: Mxx Mxy Mxz Myx Myy Myz Mzx Mzy Mzz
105 :
106 :			We currently allow there to be *at* *most* *one* axis with a
107 :			non-"space" kind. We can have non-scalar image values, but we don't
108 :			have cartesian products of non-scalar image values. The non-"space"
109 :			kind can be anywhere in the axis ordering.
110 :
111 :			----------------
112 :			space directions: (<x1>,<x2>,...,<xN>) (<x1>,<x2>,...,<xN>) ...
113 :			(and at most one of these vectors is actually "none")
114 :
115 :			These give the "direction" in world-space between successive samples
116 :			along each axis: the columns of the index-to-world transform matrix.
117 :			There is one per image axis, even for the axis of coefficients of
118 :			non-scalar image values. Because such an axis really has no spatial
119 :			extent, for this and only this axis, the space direction vector is
120 :			instead the string "none".
121 :
122 :			============================================================
123 :			Field ordering:
124 :
125 :			The fields should appear in this order:
126 :			type
127 :			dimension
128 :			space dimension
129 :			sizes
130 :			space directions
131 :			kinds
132 :			endian
133 :			encoding
134 :			space origin

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