RGB到XYZ和LAB颜色转换 [英] RGB to XYZ and LAB colours conversion

问题描述

我在将颜色从RGB转换为LAB空间时遇到问题
应该直接使用这里，只有我找回错误的值

I'm having problems converting colours from RGB to LAB space It should be straight forward using the formulas from here, only I'm getting back the wrong values

• RGB = 56,79,132

• RGB = 56,79,132

X = 8.592

X = 8.592

和CIE-L * ab as

and CIE-L*ab as

• L * 34.188


• a * 8.072


• b * -32.478

这是我的代码;但我看不出哪里出错了。这可能是由于像这样的浮点数 fella 在我之前。谢谢。

This is my code; but I can't see where I'm going wrong. It maybe due to floating points like this fella before me. Thank you.

// user colour
var Red   = 56;
var Green = 79;
var Blue  = 132;

// user colour converted to XYZ space
XYZ = RGBtoXYZ(Red,Green,Blue)
var colX = XYZ[0];
var colY = XYZ[1];
var colZ = XYZ[2];

// alert(XYZ)

LAB = XYZtoLAB(colX, colY, colZ)

alert(LAB)

function RGBtoXYZ(R, G, B)
{
    var_R = parseFloat( R / 255 )        //R from 0 to 255
    var_G = parseFloat( G / 255 )        //G from 0 to 255
    var_B = parseFloat( B / 255 )        //B from 0 to 255

    if ( var_R > 0.04045 ) var_R = ( ( var_R + 0.055 ) / 1.055 ) ^ 2.4
    else                   var_R = var_R / 12.92
    if ( var_G > 0.04045 ) var_G = ( ( var_G + 0.055 ) / 1.055 ) ^ 2.4
    else                   var_G = var_G / 12.92
    if ( var_B > 0.04045 ) var_B = ( ( var_B + 0.055 ) / 1.055 ) ^ 2.4
    else                   var_B = var_B / 12.92

    var_R = var_R * 100
    var_G = var_G * 100
    var_B = var_B * 100

    //Observer. = 2°, Illuminant = D65
    X = var_R * 0.4124 + var_G * 0.3576 + var_B * 0.1805
    Y = var_R * 0.2126 + var_G * 0.7152 + var_B * 0.0722
    Z = var_R * 0.0193 + var_G * 0.1192 + var_B * 0.9505
    return [X, Y, Z]
}


function XYZtoLAB(x, y, z)
{
    var ref_X =  95.047;
    var ref_Y = 100.000;
    var ref_Z = 108.883;

    var_X = x / ref_X          //ref_X =  95.047   Observer= 2°, Illuminant= D65
    var_Y = y / ref_Y          //ref_Y = 100.000
    var_Z = z / ref_Z          //ref_Z = 108.883

    if ( var_X > 0.008856 ) var_X = var_X ^ ( 1/3 )
    else                    var_X = ( 7.787 * var_X ) + ( 16 / 116 )
    if ( var_Y > 0.008856 ) var_Y = var_Y ^ ( 1/3 )
    else                    var_Y = ( 7.787 * var_Y ) + ( 16 / 116 )
    if ( var_Z > 0.008856 ) var_Z = var_Z ^ ( 1/3 )
    else                    var_Z = ( 7.787 * var_Z ) + ( 16 / 116 )

    CIE_L = ( 116 * var_Y ) - 16
    CIE_a = 500 * ( var_X - var_Y )
    CIE_b = 200 * ( var_Y - var_Z )

return [CIE_L, CIE_a, CIE_b]
}

推荐答案

我很确定 ^ 在javascript中是按位xor而不是电力运营商。我认为 Math.pow 正是您要找的。

I'm pretty sure ^ is bitwise xor in javascript not a power operator. I think Math.pow is what you are looking for.

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