summaryrefslogtreecommitdiffstats
path: root/include/astra/ParallelBeamLinearKernelProjector2D.inl
blob: df1a47582217f4ab6b24955fe53e07d600988200 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
/*
-----------------------------------------------------------------------
Copyright: 2010-2014, iMinds-Vision Lab, University of Antwerp
                2014, CWI, Amsterdam

Contact: astra@uantwerpen.be
Website: http://sf.net/projects/astra-toolbox

This file is part of the ASTRA Toolbox.


The ASTRA Toolbox is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

The ASTRA Toolbox is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with the ASTRA Toolbox. If not, see <http://www.gnu.org/licenses/>.

-----------------------------------------------------------------------
$Id$
*/


template <typename Policy>
void CParallelBeamLinearKernelProjector2D::project(Policy& p)
{
	projectBlock_internal(0, m_pProjectionGeometry->getProjectionAngleCount(),
	                      0, m_pProjectionGeometry->getDetectorCount(), p);
}

template <typename Policy>
void CParallelBeamLinearKernelProjector2D::projectSingleProjection(int _iProjection, Policy& p)
{
	projectBlock_internal(_iProjection, _iProjection + 1,
	                      0, m_pProjectionGeometry->getDetectorCount(), p);
}

template <typename Policy>
void CParallelBeamLinearKernelProjector2D::projectSingleRay(int _iProjection, int _iDetector, Policy& p)
{
	projectBlock_internal(_iProjection, _iProjection + 1,
	                      _iDetector, _iDetector + 1, p);
}

//----------------------------------------------------------------------------------------
// PROJECT BLOCK
template <typename Policy>
void CParallelBeamLinearKernelProjector2D::projectBlock_internal(int _iProjFrom, int _iProjTo, int _iDetFrom, int _iDetTo, Policy& p)
{
	// variables
	float32 theta, sin_theta, cos_theta, inv_sin_theta, inv_cos_theta, t;
	float32 lengthPerRow, updatePerRow, inv_pixelLengthX;
	float32 lengthPerCol, updatePerCol, inv_pixelLengthY;
	bool switch_t;
	int iAngle, iDetector, iVolumeIndex, iRayIndex;
	int row, col, x1;
	float32 P,x,x2;

	// loop angles
	for (iAngle = _iProjFrom; iAngle < _iProjTo; ++iAngle) {

		// get theta
		theta = m_pProjectionGeometry->getProjectionAngle(iAngle);
		switch_t = false;
		if (theta >= 7*PIdiv4) theta -= 2*PI;
		if (theta >= 3*PIdiv4) {
			theta -= PI;
			switch_t = true;
		}

		// precalculate sin, cos, 1/cos
		sin_theta = sin(theta);
		cos_theta = cos(theta);
		inv_cos_theta = 1.0f / cos_theta; 
		inv_sin_theta = 1.0f / sin_theta; 

		// precalculate kernel limits
		lengthPerRow = m_pVolumeGeometry->getPixelLengthY() * inv_cos_theta;
		updatePerRow = sin_theta * inv_cos_theta;
		inv_pixelLengthX = 1.0f / m_pVolumeGeometry->getPixelLengthX();

		// precalculate kernel limits
		lengthPerCol = m_pVolumeGeometry->getPixelLengthX() * inv_sin_theta;
		updatePerCol = cos_theta * inv_sin_theta;
		inv_pixelLengthY = 1.0f / m_pVolumeGeometry->getPixelLengthY();

		// loop detectors
		for (iDetector = _iDetFrom; iDetector < _iDetTo; ++iDetector) {
			
			iRayIndex = iAngle * m_pProjectionGeometry->getDetectorCount() + iDetector;

			// POLICY: RAY PRIOR
			if (!p.rayPrior(iRayIndex)) continue;
	
			// get t
			t = m_pProjectionGeometry->indexToDetectorOffset(iDetector);
			if (switch_t) {
				t = -t;
			}

			// vertically
			if (theta <= PIdiv4) {
			
				// calculate x for row 0
				P = (t - sin_theta * m_pVolumeGeometry->pixelRowToCenterY(0)) * inv_cos_theta;
				x = m_pVolumeGeometry->coordXToColF(P) - 0.5f;

				// for each row
				for (row = 0; row < m_pVolumeGeometry->getGridRowCount(); ++row) {
					
					// get coords
					x1 = int((x > 0.0f) ? x : x-1.0f);
					x2 = x - x1; 
					x += updatePerRow;

					// add weights
					if (x1 >= 0 && x1 < m_pVolumeGeometry->getGridColCount()) {
						iVolumeIndex = m_pVolumeGeometry->pixelRowColToIndex(row, x1);
						// POLICY: PIXEL PRIOR + ADD + POSTERIOR
						if (p.pixelPrior(iVolumeIndex)) {
							p.addWeight(iRayIndex, iVolumeIndex, (1.0f - x2) * lengthPerRow);
							p.pixelPosterior(iVolumeIndex);
						}
					}
					if (x1+1 >= 0 && x1+1 < m_pVolumeGeometry->getGridColCount()) {
						iVolumeIndex = m_pVolumeGeometry->pixelRowColToIndex(row, x1+1);
						// POLICY: PIXEL PRIOR + ADD + POSTERIOR
						if (p.pixelPrior(iVolumeIndex)) {
							p.addWeight(iRayIndex, iVolumeIndex, (x2) * lengthPerRow);
							p.pixelPosterior(iVolumeIndex);
						}
					}
				}
			}

			// horizontally
			else if (PIdiv4 <= theta && theta <= 3*PIdiv4) {

				// calculate point P
				P = (t - cos_theta * m_pVolumeGeometry->pixelColToCenterX(0)) * inv_sin_theta;
				x = m_pVolumeGeometry->coordYToRowF(P) - 0.5f;

				// for each row
				for (col = 0; col < m_pVolumeGeometry->getGridColCount(); ++col) {

					// get coords
					x1 = int((x > 0.0f) ? x : x-1.0f);
					x2 = x - x1; 
					x += updatePerCol;

					// add weights
					if (x1 >= 0 && x1 < m_pVolumeGeometry->getGridRowCount()) {
						iVolumeIndex = m_pVolumeGeometry->pixelRowColToIndex(x1, col);
						// POLICY: PIXEL PRIOR + ADD + POSTERIOR
						if (p.pixelPrior(iVolumeIndex)) {
							p.addWeight(iRayIndex, iVolumeIndex, (1.0f - x2) * lengthPerCol);
							p.pixelPosterior(iVolumeIndex);		
						}
					}
					if (x1+1 >= 0 && x1+1 < m_pVolumeGeometry->getGridRowCount()) {
						iVolumeIndex = m_pVolumeGeometry->pixelRowColToIndex(x1+1, col);
						// POLICY: PIXEL PRIOR + ADD + POSTERIOR
						if (p.pixelPrior(iVolumeIndex)) {
							p.addWeight(iRayIndex, iVolumeIndex, x2 * lengthPerCol);
							p.pixelPosterior(iVolumeIndex);
						}
					}
				}
			}
	
			// POLICY: RAY POSTERIOR
			p.rayPosterior(iRayIndex);
	
		} // end loop detector
	} // end loop angles

}