2011-07-08 493 views
13

我需要計算兩種顏色之間的Delta-E距離。在CIELab顏色空間的兩種顏色做這樣的算法是這樣的:CIEDE2000或CIE94 Delta-E色差計算算法是否有已知的實現?

enter image description here

是否有知道這個算法的開源實現?實現起來並不困難,但是從我實現色彩空間轉換算法的最後一次嘗試中,我寧願在已經上路並測試時不重新開發車輪。

CIEDE2000會不錯,也更準確,但也可能在iPhone上矯枉過正。我想CIE94會很好。

+0

出於興趣:此算法(使用指定的常量)是否空閒或已獲專利?這叫什麼? – Tim

+0

我相信這是一個開放的標準。更多信息:http://en.wikipedia.org/wiki/Color_difference和http://en.wikipedia.org/wiki/International_Commission_on_Illumination –

+0

您是否需要實現Delta-E距離,或者是否需要將RGB轉換爲CIELab足夠嗎? –

回答

2

我在等式中輸入(對於Common Lisp代碼,請參見底部),並且 運行了一些隨機評估。參數按以下順序列出: L * 1 a * 1 b * 1 L * 2 a * 2 b * 2 DeltaE *

我並不完全相信結果是正確的。但是如果你的代碼給出了 相同的結果,那麼它可能就足夠了。

((53.0 0.65 0.15 33.0 -0.45 -0.1 20.03112) 
    (42.0 -0.3 0.1 74.0 -0.2 -0.15 32.001118) 
    (12.0 -1.0 -0.45 32.0 0.3 0.9 20.084782) 
    (94.0 -0.1 -0.55 77.0 0.5 0.45 17.03928) 
    (75.0 -0.8 0.35 46.0 -0.6 -0.85 29.02483) 
    (83.0 -0.65 -0.7 67.0 0.75 0.0 16.074173) 
    (70.0 -0.7 0.9 54.0 0.35 -0.95 16.13608) 
    (81.0 0.45 -0.8 53.0 -0.35 0.05 28.023375) 
    (40.0 -0.2 -0.65 25.0 -1.0 0.8 15.088856) 
    (66.0 0.85 -0.7 93.0 0.55 0.15 27.014244) 
    (44.0 -0.5 0.5 23.0 -0.9 0.5 21.00363) 
    (67.0 0.4 0.25 42.0 -0.25 0.6 25.010727) 
    (32.0 0.6 0.55 86.0 0.0 0.25 54.003925) 
    (96.0 -0.15 -0.9 87.0 0.25 -0.3 9.027307) 
    (100.0 -0.6 0.3 61.0 -0.25 -0.75 39.015385) 
    (2.0 -0.2 -0.65 73.0 -0.3 0.65 71.01173) 
    (74.0 0.1 -0.65 96.0 -0.5 0.8 22.05474) 
    (22.0 -0.3 -0.85 64.0 -0.65 -0.95 42.0015) 
    (73.0 -0.35 0.3 38.0 0.25 -1.0 35.02875) 
    (91.0 0.6 0.45 82.0 -0.25 0.2 9.042115)) 

這裏是源代碼(在SBCL測試):

;; http://en.wikipedia.org/wiki/Hypot thats not necessary if numbers 
;; are not float and even if they are float the values of L*, a* and 
;; b* are bound to tiny range 
(defun hypot (x y) 
    "Compute hypotenuse, prevent overflow." 
    (declare (type number x y) 
     (values number &optional)) 
    (let ((ax (abs x)) 
    (ay (abs y))) 
    (if (or (< ax 1e-6) (< ay 1e-6)) 
    (sqrt (+ (* ax ax) (* ay ay))) 
    (if (< ay ax) 
     (* ax (sqrt (1+ (expt (/ y x) 2)))) 
     (* ay (sqrt (1+ (expt (/ x y) 2)))))))) 
#+nil 
(list 
(hypot 1 0) 
(hypot 0 1) 
(hypot (sqrt 2) (sqrt 2)) 
(hypot 2 10000)) 

;; http://www.devmaster.net/forums/archive/index.php/t-12680.html 
(defun hypot3 (x y z) 
    (hypot (hypot x y) z)) 

(defun delta-e*-94 (l1 a1 b1 l2 a2 b2 &key (application :graphic-arts)) 
    "Distance in CIE L* a* b* color space." 
    (declare (type number l1 a1 b1 l2 a2 b2) 
     (type (member :graphic-arts :textiles) application) 
     (values number &optional)) 
    (destructuring-bind (kl k1 k2) 
     (ecase application 
    (:graphic-arts '(1 .045 .015)) 
    (:textiles '(2 .048 .014))) 
    (let* ((delta-l (- l1 l2)) 
     (c1 (hypot a1 b1)) 
     (c2 (hypot a2 b2)) 
     (delta-c (- c1 c2)) 
     (delta-a (- a1 a2)) 
     (delta-b (- b1 b2)) 
     (delta-h (sqrt (+ (expt delta-a 2) 
      (expt delta-b 2) 
      (* -1 (expt delta-c 2))))) 
     (l/k (/ delta-l kl)) 
     (c/k (/ delta-c (1+ (* k1 c1)))) 
     (h/k (/ delta-h (1+ (* k2 c1))))) 
    (hypot3 l/k c/k h/k)))) 


#+nil ;; some test runs 
(labels ((rL() ;; random number from 0..100 inclusive 
     (random 101)) 
    (r-() 
     (/ (- (random 40) 20) 20)) 
    (r3() 
     (list (rL) (r-) (r-)))) 
    (loop for i below 20 collect 
    (destructuring-bind (l a b) (r3) 
    (destructuring-bind (ll aa bb) (r3) 
     (mapcar #'(lambda (x) (* 1s0 x)) 
      (list l a b ll aa bb (delta-e*-94 l a b ll aa bb))))))) 

#+nil ;; example test run 
((80.0 0.85 0.35 13.0 0.4 -0.8 67.01107) 
(11.0 0.25 -0.35 66.0 0.45 0.15 55.002594) 
(74.0 -0.55 0.45 98.0 0.7 -0.85 24.066118) 
(37.0 -0.3 0.35 60.0 0.55 -0.3 23.02452) 
(20.0 -0.85 0.5 20.0 -0.25 0.1 0.6907073) 
(23.0 0.25 -0.05 15.0 0.55 -0.8 8.039892) 
(29.0 -0.55 0.05 9.0 -0.2 -0.8 20.020708) 
(11.0 0.55 -0.45 60.0 0.9 -0.15 49.00211) 
(70.0 0.5 -0.15 66.0 -0.8 0.85 4.3169336) 
(18.0 -0.5 0.55 49.0 0.5 -0.25 31.025839) 
(27.0 -0.95 0.3 43.0 -0.1 0.2 16.021187) 
(5.0 -0.4 0.5 70.0 -0.75 -0.75 65.012665) 
(9.0 -1.0 -0.2 66.0 0.4 0.05 57.01702) 
(10.0 0.25 -0.75 13.0 -0.85 -0.75 3.1900785) 
(16.0 -0.65 -0.4 31.0 -0.6 -0.5 15.000405) 
(90.0 0.4 0.1 18.0 -0.6 -0.85 72.01298) 
(92.0 0.4 0.1 31.0 -0.7 0.2 61.009853) 
(99.0 -0.7 -0.5 40.0 -0.9 0.35 59.006287) 
(40.0 0.95 -0.2 62.0 -0.7 -0.25 22.06002) 
(16.0 0.5 0.7 35.0 0.35 -0.45 19.03436)) 
4

還有的CIE94公式的你提供了一個開源的C#實現:

https://github.com/THEjoezack/ColorMine/blob/master/ColorMine/ColorSpaces/Comparisons/Cie94Comparison.cs

它要求您的顏色在LAB色彩空間中,如果需要,其轉換源位於同一個庫中。

您也可以使用check your cIE94 calculations online使用相同的庫。

這裏的代碼中的相關片段,臘八粥及labB是輸入:

var deltaL = labA.L - labB.L; 
var deltaA = labA.A - labB.A; 
var deltaB = labA.B - labB.B; 

var c1 = Math.Sqrt(Math.Pow(labA.A, 2) + Math.Pow(labA.B, 2)); 
var c2 = Math.Sqrt(Math.Pow(labB.A, 2) + Math.Pow(labB.B, 2)); 
var deltaC = c1 - c2; 

var deltaH = Math.Pow(deltaA,2) + Math.Pow(deltaB,2) - Math.Pow(deltaC,2); 
deltaH = deltaH < 0 ? 0 : Math.Sqrt(deltaH); 

const double sl = 1.0; 
const double kc = 1.0; 
const double kh = 1.0; 

var sc = 1.0 + Constants.K1*c1; 
var sh = 1.0 + Constants.K2*c1; 

var i = Math.Pow(deltaL/(Constants.Kl*sl), 2) + 
       Math.Pow(deltaC/(kc*sc), 2) + 
       Math.Pow(deltaH/(kh*sh), 2); 
var finalResult = i < 0 ? 0 : Math.Sqrt(i); 

的「常量」是根據您的應用程序類型定義的:

case Application.GraphicArts: 
    Kl = 1.0; 
    K1 = .045; 
    K2 = .015; 
    break; 
case Application.Textiles: 
    Kl = 2.0; 
    K1 = .048; 
    K2 = .014; 
    break; 
+0

[The CIEDE2000 version](https://github.com/THEjoezack/ColorMine/blob/master/ColorMine/ColorSpaces/Comparisons/CieDe2000Comparison.cs) – Warpling

0

有一個名爲紙「 CIEDE2000色差公式:實現註釋,補充測試數據和數學觀察「,由Sharma等人撰寫。誰建議對CIEDE2000配方和價值表進行一些更正。他們還在這裏附加了MATLAB和MS Excel的實現:http://www.ece.rochester.edu/~gsharma/ciede2000/

您可以輕鬆地將excel文件集成到您的項目中,以恢復結果或在C#環境下獲得Matlab函數的工作。如果你沒有matlab,你可以很容易地讓Octave爲你做。以防萬一在C#程序中使用matlab代碼的手冊在這裏:http://www.mathworks.com/matlabcentral/fileexchange/12987-integrating-matlab-with-c

+2

歡迎使用[so]。您可能需要總結該鏈接的內容。 –

+0

更新了您的建議。希望它現在有更好的幫助。 –

相關問題