1 /**********
2 *
3 * Copyright (c) 2003, Division of Imaging Science and Biomedical Engineering,
4 * University of Manchester, UK. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without modification,
7 * are permitted provided that the following conditions are met:
8 *
9 * . Redistributions of source code must retain the above copyright notice,
10 * this list of conditions and the following disclaimer.
11 *
12 * . Redistributions in binary form must reproduce the above copyright notice,
13 * this list of conditions and the following disclaimer in the documentation
14 * and/or other materials provided with the distribution.
15 *
16 * . Neither the name of the University of Manchester nor the names of its
17 * contributors may be used to endorse or promote products derived from this
18 * software without specific prior written permission.
19 *
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
22 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
25 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 * POSSIBILITY OF SUCH DAMAGE.
32 *
33 **********
34 *
35 * Program : TINA
36 * File : $Source: /home/tina/cvs/tina-libs/tina/image/imgPrc_sample.c,v $
37 * Date : $Date: 2003/09/22 16:09:02 $
38 * Version : $Revision: 1.4 $
39 * CVS Id : $Id: imgPrc_sample.c,v 1.4 2003/09/22 16:09:02 tony Exp $
40 *
41 * Author : Legacy TINA
42 */
43
44 /**
45 * @file
46 * @brief Re-sample an image at given scale, with bi-linear interpolation.
47 *
48 */
49
50 #include "imgPrc_sample.h"
51
52 #if HAVE_CONFIG_H
53 #include <config.h>
54 #endif
55
56 #include <math.h>
57 #include <tina/sys/sysDef.h>
58 #include <tina/sys/sysPro.h>
59 #include <tina/math/mathDef.h>
60 #include <tina/math/mathPro.h>
61 #include <tina/image/img_GenDef.h>
62 #include <tina/image/img_GenPro.h>
63
64
65 Imrect *imf_sample(double k, Imrect * im)
66 {
67 Imrect *im2;
68 int width, height;
69 Imregion *region;
70 int lx, ux, ly, uy;
71 int x, y;
72
73 if (im == NULL)
74 return (NULL);
75
76 region = roi_copy(im->region);
77 lx = region->lx = (int) (region->lx * k);
78 ly = region->ly = (int) (region->ly * k);
79 ux = region->ux = (int) (region->ux * k);
80 uy = region->uy = (int) (region->uy * k);
81 width = (int) (k * im->width);
82 height = (int) (k * im->height);
83
84 im2 = im_alloc(height, width, region, float_v);
85
86 for (x = lx; x < ux; x++)
87 for (y = ly; y < uy; y++)
88 {
89 float pixval;
90
91 pixval = (float) im_sub_pixqf(im, (y + 0.5) / k, (x + 0.5) / k);
92 im_put_pixf(pixval, im2, y, x);
93 }
94
95 return (im2);
96 }
97
98 Imrect *imf_halve(Imrect * im)
99 {
100 Imrect *im2;
101 int width, height;
102 Imregion *roi;
103 int x, y;
104 double g1, g2, g3, g4, g;
105
106 if (im == NULL)
107 return (NULL);
108
109 roi = roi_copy(im->region);
110 roi->lx = (int) ceil(roi->lx / 2.0);
111 roi->ly = (int) ceil(roi->ly / 2.0);
112 roi->ux = (int) floor(roi->ux / 2.0);
113 roi->uy = (int) floor(roi->uy / 2.0);
114 width = (int) floor(im->width / 2.0);
115 height = (int) floor(im->height / 2.0);
116
117 im2 = im_alloc(height, width, roi, float_v);
118
119 for (x = roi->lx; x < roi->ux; x++)
120 for (y = roi->ly; y < roi->uy; y++)
121 {
122 int x2 = 2 * x, y2 = 2 * y;
123
124 IM_PIX_GET(im, y2, x2, g1);
125 IM_PIX_GET(im, y2 + 1, x2, g2);
126 IM_PIX_GET(im, y2, x2 + 1, g3);
127 IM_PIX_GET(im, y2 + 1, x2 + 1, g4);
128 g = 0.25 * (g1 + g2 + g3 + g4);
129 IM_PIX_SET(im2, y, x, g);
130 }
131
132 return (im2);
133 }
134
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