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