1 | /* |
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2 | * libpipi Pathetic image processing interface library |
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3 | * Copyright (c) 2004-2008 Sam Hocevar <sam@zoy.org> |
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4 | * All Rights Reserved |
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5 | * |
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6 | * $Id$ |
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7 | * |
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8 | * This library is free software. It comes without any warranty, to |
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9 | * the extent permitted by applicable law. You can redistribute it |
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10 | * and/or modify it under the terms of the Do What The Fuck You Want |
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11 | * To Public License, Version 2, as published by Sam Hocevar. See |
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12 | * http://sam.zoy.org/wtfpl/COPYING for more details. |
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13 | */ |
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14 | |
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15 | /* |
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16 | * measure.c: distance functions |
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17 | */ |
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18 | |
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19 | #include "config.h" |
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20 | #include "common.h" |
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21 | |
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22 | #include <math.h> |
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23 | |
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24 | #include "pipi.h" |
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25 | #include "pipi_internals.h" |
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26 | |
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27 | double pipi_measure_rmsd(pipi_image_t *i1, pipi_image_t *i2) |
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28 | { |
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29 | return sqrt(pipi_measure_msd(i1, i2)); |
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30 | } |
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31 | |
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32 | double pipi_measure_msd(pipi_image_t *i1, pipi_image_t *i2) |
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33 | { |
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34 | pipi_format_t f1, f2; |
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35 | double ret = 0.0; |
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36 | float *p1, *p2; |
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37 | int x, y, w, h; |
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38 | |
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39 | w = i1->w < i2->w ? i1->w : i2->w; |
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40 | h = i1->h < i2->h ? i1->h : i2->h; |
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41 | |
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42 | f1 = i1->last_modified; |
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43 | f2 = i2->last_modified; |
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44 | |
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45 | pipi_getpixels(i1, PIPI_PIXELS_Y_F); |
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46 | pipi_getpixels(i2, PIPI_PIXELS_Y_F); |
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47 | |
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48 | p1 = (float *)i1->p[PIPI_PIXELS_Y_F].pixels; |
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49 | p2 = (float *)i2->p[PIPI_PIXELS_Y_F].pixels; |
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50 | |
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51 | for(y = 0; y < h; y++) |
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52 | for(x = 0; x < w; x++) |
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53 | { |
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54 | float a = p1[y * i1->w + x]; |
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55 | float b = p2[y * i2->w + x]; |
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56 | ret += (a - b) * (a - b); |
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57 | } |
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58 | |
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59 | /* TODO: free pixels if they were allocated */ |
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60 | |
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61 | /* Restore original image formats */ |
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62 | i1->last_modified = f1; |
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63 | i2->last_modified = f2; |
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64 | |
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65 | return ret / (w * h); |
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66 | } |
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67 | |
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