RGB YUV HSV YCbCr integer conversions

SUBMITTED BY: Guest

DATE: Dec. 31, 2013, 9:14 a.m.

FORMAT: C++

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  1. typedef struct RgbColor
  2. {
  3. unsigned char r;
  4. unsigned char g;
  5. unsigned char b;
  6. } RgbColor;
  8. typedef struct HsvColor
  9. {
  10. unsigned char h;
  11. unsigned char s;
  12. unsigned char v;
  13. } HsvColor;
  15. RgbColor HsvToRgb(HsvColor hsv)
  16. {
  17. RgbColor rgb;
  18. unsigned char region, remainder, p, q, t;
  20. if (hsv.s == 0)
  21. {
  22. rgb.r = hsv.v;
  23. rgb.g = hsv.v;
  24. rgb.b = hsv.v;
  25. return rgb;
  26. }
  28. region = hsv.h / 43;
  29. remainder = (hsv.h - (region * 43)) * 6;
  31. p = (hsv.v * (255 - hsv.s)) >> 8;
  32. q = (hsv.v * (255 - ((hsv.s * remainder) >> 8))) >> 8;
  33. t = (hsv.v * (255 - ((hsv.s * (255 - remainder)) >> 8))) >> 8;
  35. switch (region)
  36. {
  37. case 0:
  38. rgb.r = hsv.v; rgb.g = t; rgb.b = p;
  39. break;
  40. case 1:
  41. rgb.r = q; rgb.g = hsv.v; rgb.b = p;
  42. break;
  43. case 2:
  44. rgb.r = p; rgb.g = hsv.v; rgb.b = t;
  45. break;
  46. case 3:
  47. rgb.r = p; rgb.g = q; rgb.b = hsv.v;
  48. break;
  49. case 4:
  50. rgb.r = t; rgb.g = p; rgb.b = hsv.v;
  51. break;
  52. default:
  53. rgb.r = hsv.v; rgb.g = p; rgb.b = q;
  54. break;
  55. }
  57. return rgb;
  58. }
  60. HsvColor RgbToHsv(RgbColor rgb)
  61. {
  62. HsvColor hsv;
  63. unsigned char rgbMin, rgbMax;
  65. rgbMin = rgb.r < rgb.g ? (rgb.r < rgb.b ? rgb.r : rgb.b) : (rgb.g < rgb.b ? rgb.g : rgb.b);
  66. rgbMax = rgb.r > rgb.g ? (rgb.r > rgb.b ? rgb.r : rgb.b) : (rgb.g > rgb.b ? rgb.g : rgb.b);
  68. hsv.v = rgbMax;
  69. if (hsv.v == 0)
  70. {
  71. hsv.h = 0;
  72. hsv.s = 0;
  73. return hsv;
  74. }
  76. hsv.s = 255 * long(rgbMax - rgbMin) / hsv.v;
  77. if (hsv.s == 0)
  78. {
  79. hsv.h = 0;
  80. return hsv;
  81. }
  83. if (rgbMax == rgb.r)
  84. hsv.h = 0 + 43 * (rgb.g - rgb.b) / (rgbMax - rgbMin);
  85. else if (rgbMax == rgb.g)
  86. hsv.h = 85 + 43 * (rgb.b - rgb.r) / (rgbMax - rgbMin);
  87. else
  88. hsv.h = 171 + 43 * (rgb.r - rgb.g) / (rgbMax - rgbMin);
  90. return hsv;
  91. }
  93. #define CLIP(X) ( (X) > 255 ? 255 : (X) < 0 ? 0 : X)
  95. // RGB -> YUV
  96. #define RGB2Y(R, G, B) CLIP(( ( 66 * (R) + 129 * (G) + 25 * (B) + 128) >> 8) + 16)
  97. #define RGB2U(R, G, B) CLIP(( ( -38 * (R) - 74 * (G) + 112 * (B) + 128) >> 8) + 128)
  98. #define RGB2V(R, G, B) CLIP(( ( 112 * (R) - 94 * (G) - 18 * (B) + 128) >> 8) + 128)
  100. // YUV -> RGB
  101. #define C(Y) ( (Y) - 16 )
  102. #define D(U) ( (U) - 128 )
  103. #define E(V) ( (V) - 128 )
  105. #define YUV2R(Y, U, V) CLIP(( 298 * C(Y) + 409 * E(V) + 128) >> 8)
  106. #define YUV2G(Y, U, V) CLIP(( 298 * C(Y) - 100 * D(U) - 208 * E(V) + 128) >> 8)
  107. #define YUV2B(Y, U, V) CLIP(( 298 * C(Y) + 516 * D(U) + 128) >> 8)
  109. // RGB -> YCbCr
  110. #define CRGB2Y(R, G, B) CLIP((19595 * R + 38470 * G + 7471 * B ) >> 16)
  111. #define CRGB2Cb(R, G, B) CLIP((36962 * (B - CLIP((19595 * R + 38470 * G + 7471 * B ) >> 16) ) >> 16) + 128)
  112. #define CRGB2Cr(R, G, B) CLIP((46727 * (R - CLIP((19595 * R + 38470 * G + 7471 * B ) >> 16) ) >> 16) + 128)
  114. // YCbCr -> RGB
  115. #define CYCbCr2R(Y, Cb, Cr) CLIP( Y + ( 91881 * Cr >> 16 ) - 179 )
  116. #define CYCbCr2G(Y, Cb, Cr) CLIP( Y - (( 22544 * Cb + 46793 * Cr ) >> 16) + 135)
  117. #define CYCbCr2B(Y, Cb, Cr) CLIP( Y + (116129 * Cb >> 16 ) - 226 )
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