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Author Topic: DeltaE2000 v DeltaE1976  (Read 1622 times)

Doug Gray

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DeltaE2000 v DeltaE1976
« on: July 10, 2016, 03:30:42 pm »

As you know dE2000 is designed to provide more accurate perceptual differences between colors than the deltaE1976 which is just the vector magnitude between L*a*b* values.

In particular, deltaE2000 more accurately shows the larger perceptual differences between hues of constant saturation. It also shows the decreased sensitivity of more saturated colors generally to changes in saturation but with constant hue.

Here are some polar charts and details around L* of 40. One showing sensitivity near the neutrals using a saturation value of 4, and one showing that of more saturated colors.

Some interesting observations. Sensitivity to Luminance change is only a function of L. Sensitivity to Saturation changes is highly dependant on the saturation level. Near neutral colors, small saturation changes are highly perceptible. As saturation increases, perceptual sensitivity rapidly decreases. Thus, at Saturation=40, and L=40, a 1.0 dE1976 from saturation alone produces a perceptual dE2000 of .36 and at higher saturation levels this difference is even more pronounced.  However, near the neutral axis, a saturation change of 1.0 dE1976 has a perceptual variation between .8 and 1.2 depending on the hue.

The biggest sensitivity changes are from hues. The greatest sensitivity to hues are at hue angles of 80 degrees (yellow), and 280 degrees (blue-violet).

Saturation=4
HueAngle=    0:  a=  4.0, b=  0.0  HueFactor= 0.89,  SatFactor= 1.18  LumFactor=0.88
HueAngle=   23:  a=  3.7, b=  1.5  HueFactor= 0.99,  SatFactor= 1.14  LumFactor=0.88
HueAngle=   45:  a=  2.8, b=  2.8  HueFactor= 1.18,  SatFactor= 1.04  LumFactor=0.88
HueAngle=   68:  a=  1.5, b=  3.7  HueFactor= 1.37,  SatFactor= 0.91  LumFactor=0.88
HueAngle=   90:  a=  0.0, b=  4.0  HueFactor= 1.45,  SatFactor= 0.85  LumFactor=0.88
HueAngle=  113:  a= -1.5, b=  3.7  HueFactor= 1.33,  SatFactor= 0.91  LumFactor=0.88
HueAngle=  135:  a= -2.8, b=  2.8  HueFactor= 1.13,  SatFactor= 1.04  LumFactor=0.88
HueAngle=  158:  a= -3.7, b=  1.5  HueFactor= 0.98,  SatFactor= 1.14  LumFactor=0.88
HueAngle=  180:  a= -4.0, b=  0.0  HueFactor= 0.92,  SatFactor= 1.18  LumFactor=0.88
HueAngle=  202:  a= -3.7, b= -1.5  HueFactor= 0.99,  SatFactor= 1.14  LumFactor=0.88
HueAngle=  225:  a= -2.8, b= -2.8  HueFactor= 1.14,  SatFactor= 1.04  LumFactor=0.88
HueAngle=  247:  a= -1.5, b= -3.7  HueFactor= 1.30,  SatFactor= 0.91  LumFactor=0.88
HueAngle=  270:  a= -0.0, b= -4.0  HueFactor= 1.44,  SatFactor= 0.85  LumFactor=0.88
HueAngle=  293:  a=  1.5, b= -3.7  HueFactor= 1.38,  SatFactor= 0.91  LumFactor=0.88
HueAngle=  315:  a=  2.8, b= -2.8  HueFactor= 1.15,  SatFactor= 1.04  LumFactor=0.88
HueAngle=  337:  a=  3.7, b= -1.5  HueFactor= 0.96,  SatFactor= 1.14  LumFactor=0.88

Saturation=40
HueAngle=    0:  a= 40.0, b=  0.0  HueFactor= 0.56,  SatFactor= 0.36  LumFactor=0.88
HueAngle=   23:  a= 37.0, b= 15.3  HueFactor= 0.65,  SatFactor= 0.36  LumFactor=0.88
HueAngle=   45:  a= 28.3, b= 28.3  HueFactor= 0.71,  SatFactor= 0.36  LumFactor=0.88
HueAngle=   68:  a= 15.3, b= 37.0  HueFactor= 0.74,  SatFactor= 0.36  LumFactor=0.88
HueAngle=   90:  a=  0.0, b= 40.0  HueFactor= 0.74,  SatFactor= 0.36  LumFactor=0.88
HueAngle=  113:  a=-15.3, b= 37.0  HueFactor= 0.64,  SatFactor= 0.36  LumFactor=0.88
HueAngle=  135:  a=-28.3, b= 28.3  HueFactor= 0.56,  SatFactor= 0.36  LumFactor=0.88
HueAngle=  158:  a=-37.0, b= 15.3  HueFactor= 0.56,  SatFactor= 0.36  LumFactor=0.88
HueAngle=  180:  a=-40.0, b=  0.0  HueFactor= 0.63,  SatFactor= 0.36  LumFactor=0.88
HueAngle=  202:  a=-37.0, b=-15.3  HueFactor= 0.61,  SatFactor= 0.36  LumFactor=0.88
HueAngle=  225:  a=-28.3, b=-28.3  HueFactor= 0.53,  SatFactor= 0.36  LumFactor=0.88
HueAngle=  247:  a=-15.3, b=-37.0  HueFactor= 0.54,  SatFactor= 0.36  LumFactor=0.88
HueAngle=  270:  a= -0.0, b=-40.0  HueFactor= 0.71,  SatFactor= 0.36  LumFactor=0.88
HueAngle=  293:  a= 15.3, b=-37.0  HueFactor= 0.82,  SatFactor= 0.36  LumFactor=0.88
HueAngle=  315:  a= 28.3, b=-28.3  HueFactor= 0.66,  SatFactor= 0.36  LumFactor=0.88
HueAngle=  337:  a= 37.0, b=-15.3  HueFactor= 0.54,  SatFactor= 0.36  LumFactor=0.88


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