Maple 18 Questions and Posts

These are Posts and Questions associated with the product, Maple 18

Here is an example of manipulating an Array of pixels. I chose the x-rite ColorChecker as a model so there would be published results to check my work. A number of details about color spaces have become clear through this exercise. The color adaptation process was modeled by converting betweenXYZ and LMS. Different black points may be selected depending on how close to zero illuminance one would accept as a good model. 

I look forward to extending this work to verify and improve the color calibration of my photography. Also some experimentation with demosaicing should be possible.

Initialization

 

restart

with(LinearAlgebra):

unprotect(gamma):``

NULL

x-rite Colorchecker xyY Matrix

  CCxyY_D50 := Matrix(4, 6, {(1, 1) = Vector(3, {(1) = .4316, (2) = .3777, (3) = .1008}), (1, 2) = Vector(3, {(1) = .4197, (2) = .3744, (3) = .3495}), (1, 3) = Vector(3, {(1) = .2760, (2) = .3016, (3) = .1836}), (1, 4) = Vector(3, {(1) = .3703, (2) = .4499, (3) = .1325}), (1, 5) = Vector(3, {(1) = .2999, (2) = .2856, (3) = .2304}), (1, 6) = Vector(3, {(1) = .2848, (2) = .3911, (3) = .4178}), (2, 1) = Vector(3, {(1) = .5295, (2) = .4055, (3) = .3118}), (2, 2) = Vector(3, {(1) = .2305, (2) = .2106, (3) = .1126}), (2, 3) = Vector(3, {(1) = .5012, (2) = .3273, (3) = .1938}), (2, 4) = Vector(3, {(1) = .3319, (2) = .2482, (3) = 0.637e-1}), (2, 5) = Vector(3, {(1) = .3984, (2) = .5008, (3) = .4446}), (2, 6) = Vector(3, {(1) = .4957, (2) = .4427, (3) = .4357}), (3, 1) = Vector(3, {(1) = .2018, (2) = .1692, (3) = 0.575e-1}), (3, 2) = Vector(3, {(1) = .3253, (2) = .5032, (3) = .2318}), (3, 3) = Vector(3, {(1) = .5686, (2) = .3303, (3) = .1257}), (3, 4) = Vector(3, {(1) = .4697, (2) = .4734, (3) = .5981}), (3, 5) = Vector(3, {(1) = .4159, (2) = .2688, (3) = .2009}), (3, 6) = Vector(3, {(1) = .2131, (2) = .3023, (3) = .1930}), (4, 1) = Vector(3, {(1) = .3469, (2) = .3608, (3) = .9131}), (4, 2) = Vector(3, {(1) = .3440, (2) = .3584, (3) = .5894}), (4, 3) = Vector(3, {(1) = .3432, (2) = .3581, (3) = .3632}), (4, 4) = Vector(3, {(1) = .3446, (2) = .3579, (3) = .1915}), (4, 5) = Vector(3, {(1) = .3401, (2) = .3548, (3) = 0.883e-1}), (4, 6) = Vector(3, {(1) = .3406, (2) = .3537, (3) = 0.311e-1})})

NULL

NULL

M := RowDimension(CCxyY_D50) = 4NULL

N := ColumnDimension(CCxyY_D50) = 6

NULL

Convert xyY to XYZ

   

NULL

CCXYZ_D50 := C_xyY_to_XYZ(CCxyY_D50):

CCXYZ_D50 = Matrix(4, 6, {(1, 1) = Vector(3, {(1) = .1152, (2) = .1008, (3) = 0.509e-1}), (1, 2) = Vector(3, {(1) = .3918, (2) = .3495, (3) = .1922}), (1, 3) = Vector(3, {(1) = .1680, (2) = .1836, (3) = .2571}), (1, 4) = Vector(3, {(1) = .1091, (2) = .1325, (3) = 0.529e-1}), (1, 5) = Vector(3, {(1) = .2419, (2) = .2304, (3) = .3344}), (1, 6) = Vector(3, {(1) = .3042, (2) = .4178, (3) = .3462}), (2, 1) = Vector(3, {(1) = .4071, (2) = .3118, (3) = 0.500e-1}), (2, 2) = Vector(3, {(1) = .1232, (2) = .1126, (3) = .2988}), (2, 3) = Vector(3, {(1) = .2968, (2) = .1938, (3) = .1015}), (2, 4) = Vector(3, {(1) = 0.852e-1, (2) = 0.637e-1, (3) = .1078}), (2, 5) = Vector(3, {(1) = .3537, (2) = .4446, (3) = 0.895e-1}), (2, 6) = Vector(3, {(1) = .4879, (2) = .4357, (3) = 0.606e-1}), (3, 1) = Vector(3, {(1) = 0.686e-1, (2) = 0.575e-1, (3) = .2138}), (3, 2) = Vector(3, {(1) = .1498, (2) = .2318, (3) = 0.790e-1}), (3, 3) = Vector(3, {(1) = .2164, (2) = .1257, (3) = 0.385e-1}), (3, 4) = Vector(3, {(1) = .5934, (2) = .5981, (3) = 0.719e-1}), (3, 5) = Vector(3, {(1) = .3108, (2) = .2009, (3) = .2356}), (3, 6) = Vector(3, {(1) = .1360, (2) = .1930, (3) = .3094}), (4, 1) = Vector(3, {(1) = .8779, (2) = .9131, (3) = .7397}), (4, 2) = Vector(3, {(1) = .5657, (2) = .5894, (3) = .4894}), (4, 3) = Vector(3, {(1) = .3481, (2) = .3632, (3) = .3029}), (4, 4) = Vector(3, {(1) = .1844, (2) = .1915, (3) = .1592}), (4, 5) = Vector(3, {(1) = 0.846e-1, (2) = 0.883e-1, (3) = 0.759e-1}), (4, 6) = Vector(3, {(1) = 0.299e-1, (2) = 0.311e-1, (3) = 0.269e-1})})NULL

XYZ D50 to XYZ D65

   

NULL

CCXYZ_D65 := XYZ_D50_to_D65(CCXYZ_D50):

CCXYZ_D65 = Matrix(4, 6, {(1, 1) = Vector(3, {(1) = .1110, (2) = 0.996e-1, (3) = 0.670e-1}), (1, 2) = Vector(3, {(1) = .3785, (2) = .3459, (3) = .2533}), (1, 3) = Vector(3, {(1) = .1726, (2) = .1861, (3) = .3403}), (1, 4) = Vector(3, {(1) = .1045, (2) = .1318, (3) = 0.690e-1}), (1, 5) = Vector(3, {(1) = .2470, (2) = .2329, (3) = .4430}), (1, 6) = Vector(3, {(1) = .3030, (2) = .4206, (3) = .4556}), (2, 1) = Vector(3, {(1) = .3850, (2) = .3044, (3) = 0.651e-1}), (2, 2) = Vector(3, {(1) = .1340, (2) = .1165, (3) = .3966}), (2, 3) = Vector(3, {(1) = .2855, (2) = .1895, (3) = .1347}), (2, 4) = Vector(3, {(1) = 0.867e-1, (2) = 0.642e-1, (3) = .1431}), (2, 5) = Vector(3, {(1) = .3334, (2) = .4409, (3) = .1142}), (2, 6) = Vector(3, {(1) = .4600, (2) = .4275, (3) = 0.777e-1}), (3, 1) = Vector(3, {(1) = 0.777e-1, (2) = 0.606e-1, (3) = .2839}), (3, 2) = Vector(3, {(1) = .1428, (2) = .2315, (3) = .1022}), (3, 3) = Vector(3, {(1) = .2063, (2) = .1216, (3) = 0.512e-1}), (3, 4) = Vector(3, {(1) = .5578, (2) = .5888, (3) = 0.906e-1}), (3, 5) = Vector(3, {(1) = .3073, (2) = .1990, (3) = .3131}), (3, 6) = Vector(3, {(1) = .1451, (2) = .1976, (3) = .4092}), (4, 1) = Vector(3, {(1) = .8646, (2) = .9129, (3) = .9759}), (4, 2) = Vector(3, {(1) = .5579, (2) = .5895, (3) = .6458}), (4, 3) = Vector(3, {(1) = .3434, (2) = .3633, (3) = .3997}), (4, 4) = Vector(3, {(1) = .1818, (2) = .1915, (3) = .2100}), (4, 5) = Vector(3, {(1) = 0.836e-1, (2) = 0.884e-1, (3) = .1002}), (4, 6) = Vector(3, {(1) = 0.296e-1, (2) = 0.311e-1, (3) = 0.355e-1})})

NULL

NULLConvert XYZ to Lab (D50 or D65 White Point)

 

NULLNULL

Reference White Point for D50

NULL

X_D50wht := XYZ_D50wht[1] = .96422NULL

Y_D50wht := XYZ_D50wht[2] = 1NULL

Z_D50wht := XYZ_D50wht[3] = .82521

NULL

Lab Conversion Constants;

`ε` := 216/24389:

kappa := 24389/27:

NULL

fx_D50 := proc (XYZ) options operator, arrow; piecewise(`&epsilon;` < XYZ[1]/X_D50wht, (XYZ[1]/X_D50wht)^(1/3), XYZ[1]/X_D50wht <= `&epsilon;`, (1/116)*kappa*XYZ[1]/X_D50wht+4/29) end proc
                

NULLNULL

NULL

 
fy_D50 := proc (XYZ) options operator, arrow; piecewise(`&epsilon;` < XYZ[2]/Y_D50wht, (XYZ[2]/Y_D50wht)^(1/3), XYZ[2]/Y_D50wht <= `&epsilon;`, (1/116)*kappa*XYZ[2]/Y_D50wht+4/29) end proc
NULLNULL

NULLNULL

fz_D50 := proc (XYZ) options operator, arrow; piecewise(`&epsilon;` < XYZ[3]/Z_D50wht, (XYZ[3]/Z_D50wht)^(1/3), XYZ[3]/Z_D50wht <= `&epsilon;`, (1/116)*kappa*XYZ[3]/Z_D50wht+4/29) end proc
NULL

XYZ_to_Lab_D50 := proc (XYZ) options operator, arrow; `<,>`(116*fy_D50(XYZ)-16, 500*fx_D50(XYZ)-500*fy_D50(XYZ), 200*fy_D50(XYZ)-200*fz_D50(XYZ)) end proc:

NULL

Reference White Point for D65

NULL

X_D65wht := XYZ_D65wht[1] = .95047NULL

Y_D65wht := XYZ_D65wht[2] = 1NULL

Z_D65wht := XYZ_D65wht[3] = 1.08883 

NULL

NULL

NULL

NULL

NULL

NULL

NULL

fx_D65 := proc (XYZ) options operator, arrow; piecewise(`&epsilon;` < XYZ[1]/X_D65wht, (XYZ[1]/X_D65wht)^(1/3), XYZ[1]/X_D65wht <= `&epsilon;`, (1/116)*kappa*XYZ[1]/X_D65wht+4/29) end proc
                

NULLNULL

NULL

 
fy_D65 := proc (XYZ) options operator, arrow; piecewise(`&epsilon;` < XYZ[2]/Y_D65wht, (XYZ[2]/Y_D65wht)^(1/3), XYZ[2]/Y_D65wht <= `&epsilon;`, (1/116)*kappa*XYZ[2]/Y_D65wht+4/29) end proc
NULLNULL

NULLNULL

fz_D65 := proc (XYZ) options operator, arrow; piecewise(`&epsilon;` < XYZ[3]/Z_D65wht, (XYZ[3]/Z_D65wht)^(1/3), XYZ[3]/Z_D65wht <= `&epsilon;`, (1/116)*kappa*XYZ[3]/Z_D65wht+4/29) end proc
NULL

XYZ_to_Lab_D65 := proc (XYZ) options operator, arrow; `<,>`(116*fy_D65(XYZ)-16, 500*fx_D65(XYZ)-500*fy_D65(XYZ), 200*fy_D65(XYZ)-200*fz_D65(XYZ)) end proc:

NULL

NULL

 

NULL

C_XYZ_to_Lab := proc (XYZ, L) options operator, arrow; piecewise(evalb(L = D50), Array([`$`('[`$`('XYZ_to_Lab_D50(XYZ[m, n])', n = 1 .. N)]', m = 1 .. M)]), evalb(L = D65), Array([`$`('[`$`('XYZ_to_Lab_D65(XYZ[m, n])', n = 1 .. N)]', m = 1 .. M)])) end proc
 NULL

NULL

NULLNULL

NULL

CCLab_D50 := C_XYZ_to_Lab(CCXYZ_D50, D50): NULL

CCLab_D50 = Matrix(4, 6, {(1, 1) = Vector(3, {(1) = 37.99, (2) = 13.55, (3) = 14.06}), (1, 2) = Vector(3, {(1) = 65.71, (2) = 18.14, (3) = 17.82}), (1, 3) = Vector(3, {(1) = 49.93, (2) = -4.91, (3) = -21.92}), (1, 4) = Vector(3, {(1) = 43.14, (2) = -13.10, (3) = 21.89}), (1, 5) = Vector(3, {(1) = 55.11, (2) = 8.84, (3) = -25.39}), (1, 6) = Vector(3, {(1) = 70.72, (2) = -33.39, (3) = -.21}), (2, 1) = Vector(3, {(1) = 62.66, (2) = 36.06, (3) = 57.08}), (2, 2) = Vector(3, {(1) = 40.01, (2) = 10.42, (3) = -45.98}), (2, 3) = Vector(3, {(1) = 51.13, (2) = 48.24, (3) = 16.26}), (2, 4) = Vector(3, {(1) = 30.33, (2) = 23.00, (3) = -21.59}), (2, 5) = Vector(3, {(1) = 72.53, (2) = -23.70, (3) = 57.27}), (2, 6) = Vector(3, {(1) = 71.94, (2) = 19.37, (3) = 67.86}), (3, 1) = Vector(3, {(1) = 28.77, (2) = 14.17, (3) = -50.30}), (3, 2) = Vector(3, {(1) = 55.26, (2) = -38.32, (3) = 31.36}), (3, 3) = Vector(3, {(1) = 42.11, (2) = 53.38, (3) = 28.20}), (3, 4) = Vector(3, {(1) = 81.73, (2) = 4.03, (3) = 79.85}), (3, 5) = Vector(3, {(1) = 51.94, (2) = 50.00, (3) = -14.57}), (3, 6) = Vector(3, {(1) = 51.04, (2) = -28.65, (3) = -28.63}), (4, 1) = Vector(3, {(1) = 96.54, (2) = -.46, (3) = 1.19}), (4, 2) = Vector(3, {(1) = 81.26, (2) = -.64, (3) = -.35}), (4, 3) = Vector(3, {(1) = 66.76, (2) = -.72, (3) = -.51}), (4, 4) = Vector(3, {(1) = 50.86, (2) = -.14, (3) = -.28}), (4, 5) = Vector(3, {(1) = 35.65, (2) = -.44, (3) = -1.23}), (4, 6) = Vector(3, {(1) = 20.48, (2) = -0.7e-1, (3) = -.98})})NULL

NULL

Convert XYZ to aRGB (XYZ D50 or D65 to aRGB D65)

 

XYZ Scaling for aRGB Ymax,Ymin (Ref. Adobe RGB (1998) Color Image Encoding Section 4.3.2.2 and 4.3.8)

NULL

White Point (Luminance=160Cd/m^2) D65

Black Point (Luminance=0.5557Cd/m^2) D65

White Point (Luminance=160Cd/m^2) D50

Black Point (Luminance=0.5557Cd/m^2) D50

XW_D65 := 152.07*(1/160) = .9504375000NULL

YW_D65 := 160*(1/160) = 1``

ZW_D65 := 174.25*(1/160) = 1.089062500``

NULL

xXK_D65 := .5282*(1/160) = 0.3301250000e-2``

xYK_D65 := .5557*(1/160) = 0.3473125000e-2``

xZK_D65 := .6025*(1/160) = 0.3765625000e-2``

XK_D65 := 0:

YK_D65 := 0:

ZK_D65 := 0:

``

``

XW_D50 := .9462:NULL

YW_D50 := 1.0000:

ZW_D50 := .8249:

``

NULL

xXK_D50 := 0.33488e-2:

xYK_D50 := 0.34751e-2:

xZK_D50 := 0.28650e-2:

``

XK_D50 := 0:

YK_D50 := 0:

ZK_D50 := 0:

NULL

 

NULL

XYZD65_to_aXYZ := proc (XYZ) options operator, arrow; `<,>`((XYZ[1]-XK_D65)*XW_D65/((XW_D65-XK_D65)*YW_D65), (XYZ[2]-YK_D65)/(YW_D65-YK_D65), (XYZ[3]-ZK_D65)*ZW_D65/((ZW_D65-ZK_D65)*YW_D65)) end proc:

XYZD50_to_aXYZ := proc (XYZ) options operator, arrow; `<,>`((XYZ[1]-XK_D50)*XW_D50/((XW_D50-XK_D50)*YW_D50), (XYZ[2]-YK_D50)/(YW_D50-YK_D50), (XYZ[3]-ZK_D50)*ZW_D50/((ZW_D50-ZK_D50)*YW_D50)) end proc:

 

NULL

(ref. Adobe RGB(1998) section 4.3.6.1, Bradford Matrix includes D50 to D65 adaptation)

M_XYZtoaRGB_D50 := Matrix(3, 3, {(1, 1) = 1.96253, (1, 2) = -.61068, (1, 3) = -.34137, (2, 1) = -.97876, (2, 2) = 1.91615, (2, 3) = 0.3342e-1, (3, 1) = 0.2869e-1, (3, 2) = -.14067, (3, 3) = 1.34926})

  aXYZ_to_RGB_D50 := proc (aXYZ) options operator, arrow; `<,>`(Typesetting:-delayDotProduct(M_XYZtoaRGB_D50, aXYZ)) end proc: NULL

 

(ref. Adobe RBG(1998) section 4.3.4.1, Bradford Matrix assumes XYZ is D65)

M_XYZtoaRGB_D65 := Matrix(3, 3, {(1, 1) = 2.04159, (1, 2) = -.56501, (1, 3) = -.34473, (2, 1) = -.96924, (2, 2) = 1.87597, (2, 3) = 0.4156e-1, (3, 1) = 0.1344e-1, (3, 2) = -.11836, (3, 3) = 1.01517})

  NULL

aXYZ_to_RGB_D65 := proc (aXYZ) options operator, arrow; `<,>`(Typesetting:-delayDotProduct(M_XYZtoaRGB_D65, aXYZ)) end proc:

NULL

  aRGB Expansion for 8bits

 

`&gamma;a` := 2.19921875:

RGB_to_aRGB := proc (RGB) options operator, arrow; `<,>`(round(255*Norm(RGB[1])^(1/`&gamma;a`)), round(255*Norm(RGB[2])^(1/`&gamma;a`)), round(255*Norm(RGB[3])^(1/`&gamma;a`))) end proc:
NULL

 

Combine Steps

NULL

XYZ_to_aRGB := proc (XYZ, L) options operator, arrow; piecewise(evalb(L = D50), Array([`$`('[`$`('RGB_to_aRGB(aXYZ_to_RGB_D50(XYZD50_to_aXYZ(XYZ[m, n])))', n = 1 .. N)]', m = 1 .. M)]), evalb(L = D65), Array([`$`('[`$`('RGB_to_aRGB(aXYZ_to_RGB_D65(XYZD65_to_aXYZ(XYZ[m, n])))', n = 1 .. N)]', m = 1 .. M)])) end proc

NULLNULL

NULLNULL

Note: The aRGB values published for ColorChecker assume a black point of 0cd/m^2.

````

aRGB_D50in := XYZ_to_aRGB(CCXYZ_D50, D50):

aRGB_D50in = Matrix(4, 6, {(1, 1) = Vector(3, {(1) = 107, (2) = 82, (3) = 70}), (1, 2) = Vector(3, {(1) = 184, (2) = 146, (3) = 128}), (1, 3) = Vector(3, {(1) = 101, (2) = 122, (3) = 153}), (1, 4) = Vector(3, {(1) = 95, (2) = 107, (3) = 69}), (1, 5) = Vector(3, {(1) = 128, (2) = 127, (3) = 173}), (1, 6) = Vector(3, {(1) = 129, (2) = 188, (3) = 171}), (2, 1) = Vector(3, {(1) = 201, (2) = 123, (3) = 56}), (2, 2) = Vector(3, {(1) = 77, (2) = 92, (3) = 166}), (2, 3) = Vector(3, {(1) = 174, (2) = 83, (3) = 97}), (2, 4) = Vector(3, {(1) = 86, (2) = 61, (3) = 104}), (2, 5) = Vector(3, {(1) = 167, (2) = 188, (3) = 75}), (2, 6) = Vector(3, {(1) = 213, (2) = 160, (3) = 55}), (3, 1) = Vector(3, {(1) = 49, (2) = 65, (3) = 143}), (3, 2) = Vector(3, {(1) = 99, (2) = 148, (3) = 80}), (3, 3) = Vector(3, {(1) = 155, (2) = 52, (3) = 59}), (3, 4) = Vector(3, {(1) = 227, (2) = 197, (3) = 52}), (3, 5) = Vector(3, {(1) = 169, (2) = 85, (3) = 147}), (3, 6) = Vector(3, {(1) = 61, (2) = 135, (3) = 167}), (4, 1) = Vector(3, {(1) = 245, (2) = 245, (3) = 242}), (4, 2) = Vector(3, {(1) = 200, (2) = 201, (3) = 201}), (4, 3) = Vector(3, {(1) = 160, (2) = 161, (3) = 162}), (4, 4) = Vector(3, {(1) = 120, (2) = 120, (3) = 121}), (4, 5) = Vector(3, {(1) = 84, (2) = 85, (3) = 86}), (4, 6) = Vector(3, {(1) = 52, (2) = 53, (3) = 54})})NULL

  

NULL

aRGB_D65in := XYZ_to_aRGB(CCXYZ_D65, D65):

aRGB_D65in = Matrix(4, 6, {(1, 1) = Vector(3, {(1) = 107, (2) = 82, (3) = 70}), (1, 2) = Vector(3, {(1) = 184, (2) = 146, (3) = 128}), (1, 3) = Vector(3, {(1) = 101, (2) = 122, (3) = 153}), (1, 4) = Vector(3, {(1) = 95, (2) = 107, (3) = 69}), (1, 5) = Vector(3, {(1) = 128, (2) = 127, (3) = 173}), (1, 6) = Vector(3, {(1) = 129, (2) = 188, (3) = 171}), (2, 1) = Vector(3, {(1) = 201, (2) = 123, (3) = 56}), (2, 2) = Vector(3, {(1) = 77, (2) = 92, (3) = 166}), (2, 3) = Vector(3, {(1) = 174, (2) = 83, (3) = 97}), (2, 4) = Vector(3, {(1) = 86, (2) = 61, (3) = 104}), (2, 5) = Vector(3, {(1) = 167, (2) = 188, (3) = 75}), (2, 6) = Vector(3, {(1) = 213, (2) = 160, (3) = 55}), (3, 1) = Vector(3, {(1) = 49, (2) = 65, (3) = 143}), (3, 2) = Vector(3, {(1) = 99, (2) = 148, (3) = 80}), (3, 3) = Vector(3, {(1) = 155, (2) = 52, (3) = 59}), (3, 4) = Vector(3, {(1) = 227, (2) = 197, (3) = 52}), (3, 5) = Vector(3, {(1) = 169, (2) = 85, (3) = 147}), (3, 6) = Vector(3, {(1) = 61, (2) = 135, (3) = 167}), (4, 1) = Vector(3, {(1) = 245, (2) = 245, (3) = 242}), (4, 2) = Vector(3, {(1) = 200, (2) = 201, (3) = 201}), (4, 3) = Vector(3, {(1) = 160, (2) = 161, (3) = 162}), (4, 4) = Vector(3, {(1) = 120, (2) = 120, (3) = 121}), (4, 5) = Vector(3, {(1) = 84, (2) = 85, (3) = 86}), (4, 6) = Vector(3, {(1) = 52, (2) = 53, (3) = 54})})

Convert XYZ to ProPhoto RGB (D50)

   

NULL

CC_PPhoto := XYZ_to_PPhoto(CCXYZ_D50):

NULL

CC_PPhoto = Matrix(4, 6, {(1, 1) = Vector(3, {(1) = 81, (2) = 67, (3) = 54}), (1, 2) = Vector(3, {(1) = 159, (2) = 135, (3) = 113}), (1, 3) = Vector(3, {(1) = 94, (2) = 102, (3) = 133}), (1, 4) = Vector(3, {(1) = 75, (2) = 86, (3) = 55}), (1, 5) = Vector(3, {(1) = 118, (2) = 111, (3) = 154}), (1, 6) = Vector(3, {(1) = 127, (2) = 168, (3) = 157}), (2, 1) = Vector(3, {(1) = 167, (2) = 118, (3) = 54}), (2, 2) = Vector(3, {(1) = 79, (2) = 74, (3) = 145}), (2, 3) = Vector(3, {(1) = 141, (2) = 83, (3) = 80}), (2, 4) = Vector(3, {(1) = 68, (2) = 49, (3) = 82}), (2, 5) = Vector(3, {(1) = 144, (2) = 170, (3) = 74}), (2, 6) = Vector(3, {(1) = 181, (2) = 152, (3) = 60}), (3, 1) = Vector(3, {(1) = 57, (2) = 50, (3) = 120}), (3, 2) = Vector(3, {(1) = 85, (2) = 123, (3) = 69}), (3, 3) = Vector(3, {(1) = 120, (2) = 59, (3) = 46}), (3, 4) = Vector(3, {(1) = 199, (2) = 188, (3) = 66}), (3, 5) = Vector(3, {(1) = 143, (2) = 85, (3) = 127}), (3, 6) = Vector(3, {(1) = 78, (2) = 111, (3) = 148}), (4, 1) = Vector(3, {(1) = 242, (2) = 243, (3) = 240}), (4, 2) = Vector(3, {(1) = 189, (2) = 190, (3) = 191}), (4, 3) = Vector(3, {(1) = 145, (2) = 146, (3) = 146}), (4, 4) = Vector(3, {(1) = 102, (2) = 102, (3) = 102}), (4, 5) = Vector(3, {(1) = 66, (2) = 66, (3) = 68}), (4, 6) = Vector(3, {(1) = 37, (2) = 37, (3) = 38})})NULL

Convert XYZ to sRGB (XYZ D50 or D65 to sRGB D65)

   

NULL

Note: The sRGB values published for ColorChecker assume a black point of 0cd/m^2.

``

CCsRGB_D65in := XYZ_to_sRGB(CCXYZ_D65, D65):

NULL

CCsRGB_D65in = Matrix(4, 6, {(1, 1) = Vector(3, {(1) = 115, (2) = 81, (3) = 67}), (1, 2) = Vector(3, {(1) = 199, (2) = 147, (3) = 129}), (1, 3) = Vector(3, {(1) = 91, (2) = 122, (3) = 156}), (1, 4) = Vector(3, {(1) = 90, (2) = 108, (3) = 64}), (1, 5) = Vector(3, {(1) = 130, (2) = 128, (3) = 176}), (1, 6) = Vector(3, {(1) = 92, (2) = 190, (3) = 172}), (2, 1) = Vector(3, {(1) = 224, (2) = 124, (3) = 47}), (2, 2) = Vector(3, {(1) = 68, (2) = 91, (3) = 170}), (2, 3) = Vector(3, {(1) = 198, (2) = 82, (3) = 97}), (2, 4) = Vector(3, {(1) = 94, (2) = 58, (3) = 106}), (2, 5) = Vector(3, {(1) = 159, (2) = 189, (3) = 63}), (2, 6) = Vector(3, {(1) = 230, (2) = 162, (3) = 39}), (3, 1) = Vector(3, {(1) = 35, (2) = 63, (3) = 147}), (3, 2) = Vector(3, {(1) = 67, (2) = 149, (3) = 74}), (3, 3) = Vector(3, {(1) = 180, (2) = 49, (3) = 57}), (3, 4) = Vector(3, {(1) = 238, (2) = 198, (3) = 20}), (3, 5) = Vector(3, {(1) = 193, (2) = 84, (3) = 151}), (3, 6) = Vector(3, {(1) = 54, (2) = 136, (3) = 170}), (4, 1) = Vector(3, {(1) = 245, (2) = 245, (3) = 243}), (4, 2) = Vector(3, {(1) = 200, (2) = 202, (3) = 202}), (4, 3) = Vector(3, {(1) = 161, (2) = 163, (3) = 163}), (4, 4) = Vector(3, {(1) = 121, (2) = 121, (3) = 122}), (4, 5) = Vector(3, {(1) = 82, (2) = 84, (3) = 86}), (4, 6) = Vector(3, {(1) = 49, (2) = 49, (3) = 51})})NULL

``

CCsRGB_D50in := XYZ_to_sRGB(CCXYZ_D50, D50):

``

CCsRGB_D50in = Matrix(4, 6, {(1, 1) = Vector(3, {(1) = 115, (2) = 81, (3) = 67}), (1, 2) = Vector(3, {(1) = 199, (2) = 148, (3) = 129}), (1, 3) = Vector(3, {(1) = 91, (2) = 123, (3) = 156}), (1, 4) = Vector(3, {(1) = 90, (2) = 108, (3) = 64}), (1, 5) = Vector(3, {(1) = 130, (2) = 129, (3) = 176}), (1, 6) = Vector(3, {(1) = 92, (2) = 190, (3) = 172}), (2, 1) = Vector(3, {(1) = 224, (2) = 125, (3) = 47}), (2, 2) = Vector(3, {(1) = 68, (2) = 92, (3) = 170}), (2, 3) = Vector(3, {(1) = 198, (2) = 83, (3) = 97}), (2, 4) = Vector(3, {(1) = 94, (2) = 59, (3) = 106}), (2, 5) = Vector(3, {(1) = 159, (2) = 190, (3) = 63}), (2, 6) = Vector(3, {(1) = 230, (2) = 163, (3) = 39}), (3, 1) = Vector(3, {(1) = 35, (2) = 64, (3) = 147}), (3, 2) = Vector(3, {(1) = 67, (2) = 149, (3) = 74}), (3, 3) = Vector(3, {(1) = 180, (2) = 51, (3) = 57}), (3, 4) = Vector(3, {(1) = 238, (2) = 199, (3) = 20}), (3, 5) = Vector(3, {(1) = 193, (2) = 85, (3) = 151}), (3, 6) = Vector(3, {(1) = 54, (2) = 137, (3) = 170}), (4, 1) = Vector(3, {(1) = 245, (2) = 246, (3) = 243}), (4, 2) = Vector(3, {(1) = 200, (2) = 203, (3) = 202}), (4, 3) = Vector(3, {(1) = 161, (2) = 164, (3) = 163}), (4, 4) = Vector(3, {(1) = 121, (2) = 122, (3) = 122}), (4, 5) = Vector(3, {(1) = 82, (2) = 84, (3) = 86}), (4, 6) = Vector(3, {(1) = 49, (2) = 50, (3) = 51})})``

NULL

``

NULL

NULL

``

 

 

 

 

 

 

 

 

``

 

Corrections to the original version of theis document;
• Make the scaling for a nonzero black point the same for all RGB color spaces.
• Clip negative RGB values to zero.
• Remove the redundant Array container from matrix multiplications.
Use map in place of the $ to apply a function to each element of an Array.

Pixel_Conversion_B.mw

 

Hi, 

 

  I would like to a string of characters to a file. For example,

***

str:="hello world";
WriteFile[APPEND]("D:\\output3.txt", str);

***

 

  It doesn't work. I did not get output3.txt :(  How should I do, to write a string of characters, such as "hello world" to a file?

Thank you

Good morning.

 

I am working on engineering drawing project. I request your kind suggestions for

the above cited subject.

 

 

With thanks & Regards

 

M.Anand

Assistant Professor in Mathematics

SR International Institute of Technology,

Hyderabad, Andhra Pradesh, INDIA.

Say I have

a.mpl

b.mpl

c.mpl

each of them can be ran seperately. While I am running a single file, it looks like that the machine is not "using" too much computation power. I wonder if it's possible to run multiple at the same time ?

My CPU is i7 940X, with 4 dual core processors, so it has 8 threads.

I know that the GUI can run multiple worksheets seperately, but if in one of the worksheet, i click "run all" (!!! botton),  I will have to run each line separtely by clicking one at a time.

Is there a better way to do this? What's the best way to do this? I hope to somehow 'maximize' the full use of my CPU (without changing the code).

 

casper

Hi,

 

  I have a loop code, such as

 

****

i_max:=10;

for i from 1 to i_max do
  blah blah blah

end do;

****

 

  I would like to clean memory, something like restart suppose to do, after each cycle. Restart could only work at top level. How should I do to clean memory after each cycle?

 

Hi,

I am connected to the linux version of Maple (xmaple) via putty and Xing (for GUI).

While the "big" code is running, I sometimes I got these messages,

But Maple (xmaple GUI) keeps running. It looks like it does not have an effect.

 

Should I be concerned?

At the moment, I am using

>writeto("Result1.txt");

> printf(StringTools[FormatTime]("%c\n"));
Thu Jul 31 14:28:08 2014

# lots of things here

# lots of things here

# lots of things here

>writeto(terminal);

To write a time and date stamp into my result1.txt file.

I understand that I can't write : into file names, but is there a way to writeto file using a more informative file name with date and time, such as,

Result_Thu Jul 31 14-28-08 2014.txt

 

Is that something can be easily formatted?

casper

 

Hi Maple friends.

Is there a Maple function to determine the intersection of two curves? For simple curves where the intersection is clear, I can plot them and use probeinfo to get the approximate intersection values.

But for more complex curves, where the scales are large, or the intersection point is not clear, it is difficult.

ie. intersection of y=x-3 and y=x^2-2*x-1

or intersection of y=x+1 and y=(x+1)/(x-1)

Thanks in advance.

Say sometimes, I need to copy and paste results from Maple output, either in 1D or 2D or self formatted (see this).

Sometimes, it works fine, with just a single ">" sign, like this

> v1:=[
eta[p2] = 0.260 ,
eta[p3] = 0.113 ,
eta[p4] = -0.013 ,
eta[p5] = 0.215 ,
eta[p6] = -0.189 ,
eta[phi2] = 0.020 ,
.......ect
]:

 

But sometimes, it looks like this:

 

> v1:=[
> eta[p2] = 0.260 ,
> eta[p3] = 0.113 ,
> eta[p4] = -0.013 ,
> eta[p5] = 0.215 ,
> eta[p6] = -0.189 ,
> eta[phi2] = 0.020 ,
> .......ect
> ]:

 

Below is a screenshot from what I get when I copy the above synatex into Maple :

 

Personally, when I type in multiple synatex, I tend to use shift+enter, to avoid the use of many ">"s.

 

It does not have any effect in practice, but is there a way to improve this? I dont like seeing many many ">"s.

restart:

a:=0.0000000000000000000000213123123;

evalf[3](a);

I think the above is the same as if I were to change the precision tab, to display 3 decimals.

Is there a way to ask Maple to display it as  (printf(  "%3.3f",a);)

0.000

But I want this as a standard Maple ouput.

and I am not just working with a single scalar, I need something that works for a Vector, Matrix, and perhaps, in general.

 

Thanks,

 

casper

v1:=[
eta[p2] = 0.260 ,
eta[p3] = 0.113 ,
eta[p4] = -0.013 ,
eta[p5] = 0.215 ,
eta[p6] = -0.189 ,
eta[phi2] = 0.020 ,
eta[phi3] = 0.063 ,
eta[phi4] = -0.014 ,
eta[phi5] = -0.414 ,
eta[phi6] = 0.067 ,
mu[p] = 0.466 ,
mu[phi] = -0.169 ,
tau[p3] = -0.000 ,
tau[p4] = 0.000 ,
w[1] = 0.023 ,
w[2] = -0.447 ,
w[3] = -0.110 ,
w[4] = 0.035 ,
w[5] = 0.445
]:

for i to numelems(v1) do
    printf("%a = %3.3f , \n",lhs(v1[i]),rhs(v1[i]));
end do:

This runs and returns:

eta[p2] = 0.260 ,
eta[p3] = 0.113 ,
eta[p4] = -0.013 ,
eta[p5] = 0.215 ,
eta[p6] = -0.189 ,
eta[phi2] = 0.020 ,
eta[phi3] = 0.063 ,
eta[phi4] = -0.014 ,
eta[phi5] = -0.414 ,
eta[phi6] = 0.067 ,
mu[p] = 0.466 ,
mu[phi] = -0.169 ,
tau[p3] = 0.000 ,
tau[p4] = 0.000 ,
w[1] = 0.023 ,
w[2] = -0.447 ,
w[3] = -0.110 ,
w[4] = 0.035 ,
w[5] = 0.445 ,

 

Is there a way to align the qual signs? also to align the decials like this:

 

eta[p2]   =  0.260 ,
eta[p3]   =  0.113 ,
eta[p4]   = -0.013 ,
eta[p5]   =  0.215 ,
eta[p6]   = -0.189 ,
eta[phi2] =  0.020 ,
eta[phi3] =  0.063 ,
eta[phi4] = -0.014 ,
eta[phi5] = -0.414 ,
eta[phi6] =  0.067 ,
mu[p]     =  0.466 ,
mu[phi]   = -0.169 ,
tau[p3]   =   0.000 ,
tau[p4]   =   0.000 ,
w[1]       =   0.023 ,
w[2]       = -0.447 ,
w[3]       = -0.110 ,
w[4]       =  0.035 ,
w[5]       =  0.445 ,

For the negative numbers, I prefer to have 1 space of indentation.

 

Thanks,

 

casper

We deploy Maple to our users using Microsoft App-V; We have been using App-V 4  to successfully deploy Maple for some time. When I package Maple 18 for App-V 5 deployment, when a user launches Maple there is an error "too many levels of recursion".

After clicking OK to clear the error, choosing any of the options on the start screen, e.g. signal processing, simply launches a help screen with the message "no matches found" instead of launching a new worksheet.

App-V is our standard method of deploying applications, and has always worked OK in the past. Do you have any recommendations for packaging Maple 18 via App-V?

Thanks.

 

Hi,

 

  Excuse me, I have a following expression

x^2+x+2;

  I want to replace all x as x+1

x:=x+1 does not work.

Is there any simple solution?

 

Thank you very much in advance

 

 

hi,

   here are  equations like this

 sol := [abs(r)^2+abs(t)^2 = 1, r*conjugate(t)+t*conjugate(r), abs(r) = abs(t)]

when i solve this equations using command solve,the result  is none. and i used r=x+I*y,t=u+I*v in the equations,

sol:=[u^2+v^2+x^2+y^2 = 1, 2*u*x+2*v*y, sqrt(x^2+y^2) = sqrt(u^2+v^2)]

i still can't get a result.why,can you help me.

thanks.

 

a:=Vector([2,3,4,5]);

select[flatten](x->x>=3,a);

This returns a Vector that satisfies the above condition. What's the most efficient way to get the indices of those entries?

For example, a list l:=[2,3,4] that correspond to the a[l] entries that satisfies the above condition.

l:=[2,3,4];

a[l]; # gives the same answer

 

Thanks,

 

casper

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