* implement lab2rgb & rgb2lab

sipeed · Apr 16, 2024 · ba2dea1 · ba2dea1
1 parent 942d653
commit ba2dea1
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diff --git a/examples/maixpy_v1/image/invert_format.py b/examples/maixpy_v1/image/invert_format.py
@@ -18,5 +18,19 @@
 lcd.display(img)
 time.sleep(1)
 
+rgb=(100,200,30)
+lab=image.rgb_to_lab(rgb)
+print('rgb to lab, res:', lab)
+
+rgb=image.lab_to_rgb(lab)
+print('lab to rgb, res:', rgb)
+
+rgb=(10,20,30)
+gray=image.rgb_to_grayscale(rgb)
+print('rgb to gray, res:', gray)
+
+rgb=image.grayscale_to_rgb(gray)
+print('gray to rgb, res:', rgb)
+
 while True:
     time.sleep(1)
diff --git a/maix/v1/image.py b/maix/v1/image.py
@@ -1,4 +1,5 @@
 from maix import image
+import math
 
 SEARCH_EX       = 0
 SEARCH_DS       = 1
@@ -718,17 +719,174 @@ def find_edges(self, edge_type, threshold):
 
         return img_v1
 
+def RGB2XYZ(r, g, b):
+    x = 0.412453 * r + 0.357580 * g + 0.180423 * b
+    y = 0.212671 * r + 0.715160 * g + 0.072169 * b
+    z = 0.019334 * r + 0.119193 * g + 0.950227 * b
+    return x, y, z
+
+def XYZ2Lab(x, y, z):
+    Xn = 1.0
+    Yn = 1.0
+    Zn = 1.0
+    param_13 = 1.0 / 3.0
+    param_16116 = 16.0 / 116.0
+
+    x /=  255 * Xn
+    y /= 255 * Yn
+    z /= 255 * Zn
+    if y > 0.008856:
+        fy = pow(y, param_13)
+        l = 116.0 * fy - 16.0
+    else:
+        fy = 7.787 * y + param_16116
+        l = 903.3 * fy
+
+    if l < 0:
+        l = 0.0
+
+    if x>0.008856:
+        fx = pow(x,param_13)
+    else:
+        fx = 7.787 * x + param_16116
+
+    if z>0.008856:
+        fz = pow(z,param_13)
+    else:
+        fz = 7.787 * z + param_16116
+
+    a = 500.0*(fx-fy)
+    b = 200.0*(fy-fz)
+
+    return (round(l,2), round(a,2), round(b,2))
+
+__xyz_table = [
+    0.000000,  0.030353,  0.060705,  0.091058,  0.121411,  0.151763,  0.182116,  0.212469,
+    0.242822,  0.273174,  0.303527,  0.334654,  0.367651,  0.402472,  0.439144,  0.477695,
+    0.518152,  0.560539,  0.604883,  0.651209,  0.699541,  0.749903,  0.802319,  0.856813,
+    0.913406,  0.972122,  1.032982,  1.096009,  1.161225,  1.228649,  1.298303,  1.370208,
+    1.444384,  1.520851,  1.599629,  1.680738,  1.764195,  1.850022,  1.938236,  2.028856,
+    2.121901,  2.217388,  2.315337,  2.415763,  2.518686,  2.624122,  2.732089,  2.842604,
+    2.955683,  3.071344,  3.189603,  3.310477,  3.433981,  3.560131,  3.688945,  3.820437,
+    3.954624,  4.091520,  4.231141,  4.373503,  4.518620,  4.666509,  4.817182,  4.970657,
+    5.126946,  5.286065,  5.448028,  5.612849,  5.780543,  5.951124,  6.124605,  6.301002,
+    6.480327,  6.662594,  6.847817,  7.036010,  7.227185,  7.421357,  7.618538,  7.818742,
+    8.021982,  8.228271,  8.437621,  8.650046,  8.865559,  9.084171,  9.305896,  9.530747,
+    9.758735,  9.989873, 10.224173, 10.461648, 10.702310, 10.946171, 11.193243, 11.443537,
+    11.697067, 11.953843, 12.213877, 12.477182, 12.743768, 13.013648, 13.286832, 13.563333,
+    13.843162, 14.126329, 14.412847, 14.702727, 14.995979, 15.292615, 15.592646, 15.896084,
+    16.202938, 16.513219, 16.826940, 17.144110, 17.464740, 17.788842, 18.116424, 18.447499,
+    18.782077, 19.120168, 19.461783, 19.806932, 20.155625, 20.507874, 20.863687, 21.223076,
+    21.586050, 21.952620, 22.322796, 22.696587, 23.074005, 23.455058, 23.839757, 24.228112,
+    24.620133, 25.015828, 25.415209, 25.818285, 26.225066, 26.635560, 27.049779, 27.467731,
+    27.889426, 28.314874, 28.744084, 29.177065, 29.613827, 30.054379, 30.498731, 30.946892,
+    31.398871, 31.854678, 32.314321, 32.777810, 33.245154, 33.716362, 34.191442, 34.670406,
+    35.153260, 35.640014, 36.130678, 36.625260, 37.123768, 37.626212, 38.132601, 38.642943,
+    39.157248, 39.675523, 40.197778, 40.724021, 41.254261, 41.788507, 42.326767, 42.869050,
+    43.415364, 43.965717, 44.520119, 45.078578, 45.641102, 46.207700, 46.778380, 47.353150,
+    47.932018, 48.514994, 49.102085, 49.693300, 50.288646, 50.888132, 51.491767, 52.099557,
+    52.711513, 53.327640, 53.947949, 54.572446, 55.201140, 55.834039, 56.471151, 57.112483,
+    57.758044, 58.407842, 59.061884, 59.720179, 60.382734, 61.049557, 61.720656, 62.396039,
+    63.075714, 63.759687, 64.447968, 65.140564, 65.837482, 66.538730, 67.244316, 67.954247,
+    68.668531, 69.387176, 70.110189, 70.837578, 71.569350, 72.305513, 73.046074, 73.791041,
+    74.540421, 75.294222, 76.052450, 76.815115, 77.582222, 78.353779, 79.129794, 79.910274,
+    80.695226, 81.484657, 82.278575, 83.076988, 83.879901, 84.687323, 85.499261, 86.315721,
+    87.136712, 87.962240, 88.792312, 89.626935, 90.466117, 91.309865, 92.158186, 93.011086,
+    93.868573, 94.730654, 95.597335, 96.468625, 97.344529, 98.225055, 99.110210, 100.000000
+]
+
 def rgb_to_lab(rgb_tuple):
-    raise ValueError('This operation is not supported')
+    r = int(rgb_tuple[0])
+    g = int(rgb_tuple[1])
+    b = int(rgb_tuple[2])
+
+    r_lin = __xyz_table[r]
+    g_lin = __xyz_table[g]
+    b_lin = __xyz_table[b]
+
+    x = ((r_lin * 0.4124) + (g_lin * 0.3576) + (b_lin * 0.1805)) * (1.0 / 95.047)
+    y = ((r_lin * 0.2126) + (g_lin * 0.7152) + (b_lin * 0.0722)) * (1.0 / 100.000)
+    z = ((r_lin * 0.0193) + (g_lin * 0.1192) + (b_lin * 0.9505)) * (1.0 / 108.883)
+
+    if x > 0.008856:
+        x = x ** (1 / 3)
+    else:
+        x = (x * 7.787037) + 0.137931
+
+    if y > 0.008856:
+        y = y ** (1 / 3)
+    else:
+        y = (y * 7.787037) + 0.137931
+
+    if z > 0.008856:
+        z = z ** (1 / 3)
+    else:
+        z = (z * 7.787037) + 0.137931
+
+    l = max(min(math.floor(116 * y) - 16, 100), 0)
+    a = max(min(math.floor(500 * (x-y)), 127), -128)
+    b = max(min(math.floor(200 * (y-z)), 127), -128)
+
+    return (l,a,b)
 
 def lab_to_rgb(lab_tuple):
-    raise ValueError('This operation is not supported')
+    l = int(lab_tuple[0])
+    a = int(lab_tuple[1])
+    b = int(lab_tuple[2])
+
+    x = ((l + 16) * 0.008621) + (a * 0.002)
+    y = ((l + 16) * 0.008621)
+    z = ((l + 16) * 0.008621) - (b * 0.005)
+
+    if x > 0.206897:
+        x = x * x * x * 95.047
+    else:
+        x = (((0.128419 * x) - 0.017713)) * 95.047
+
+    if y > 0.206897:
+        y = y * y * y * 100.000
+    else:
+        y = ((0.128419 * y) - 0.017713) * 100.000
+
+    if z > 0.206897:
+        z = z * z * z * 108.883
+    else:
+        z = ((0.128419 * z) - 0.017713) * 108.883
+
+    r_lin = ((x * +3.2406) + (y * -1.5372) + (z * -0.4986)) / 100.0
+    g_lin = ((x * -0.9689) + (y * +1.8758) + (z * +0.0415)) / 100.0
+    b_lin = ((x * +0.0557) + (y * -0.2040) + (z * +1.0570)) / 100.0
+
+    if r_lin > 0.0031308:
+        r_lin = 1.055 * (r_lin ** 0.416666) - 0.055
+    else:
+        r_lin = r_lin * 12.92
+
+    if g_lin > 0.0031308:
+        g_lin = 1.055 * (g_lin ** 0.416666) - 0.055
+    else:
+        g_lin = g_lin * 12.92
+
+    if b_lin > 0.0031308:
+        b_lin = 1.055 * (b_lin ** 0.416666) - 0.055
+    else:
+        r_lin = r_lin * 12.92
+
+    r = max(min(math.floor(r_lin * 255), 255), 0)
+    g = max(min(math.floor(g_lin * 255), 255), 0)
+    b = max(min(math.floor(b_lin * 255), 255), 0)
+
+    return (r,g,b)
 
 def rgb_to_grayscale(rgb_tuple):
-    raise ValueError('This operation is not supported')
+    r = rgb_tuple[0]
+    g = rgb_tuple[1]
+    b = rgb_tuple[2]
+    y = ((((r) * 38) + ((g) * 75) + ((b) * 15)) >> 7)
+    return y
 
 def grayscale_to_rgb(g_value):
-    raise ValueError('This operation is not supported')
+    return (g_value, g_value, g_value)
 
 def load_decriptor(path):
     raise ValueError('This operation is not supported')