# Colour Difference

## Delta E

colour

 delta_E(a, b[, method]) Returns the difference $$\Delta E_{ab}$$ between two given CIE L*a*b* or $$J'a'b'$$ colourspace arrays using given method. DELTA_E_METHODS Supported $$\Delta E_{ab}$$ computation methods.

## CIE 1976

colour.difference

 JND_CIE1976 Just Noticeable Difference (JND) according to CIE 1976 colour difference formula, i.e. Euclidean distance in CIE L*a*b* colourspace. delta_E_CIE1976(Lab_1, Lab_2) Returns the difference $$\Delta E_{76}$$ between two given CIE L*a*b* colourspace arrays using CIE 1976 recommendation.

## CIE 1994

colour.difference

 delta_E_CIE1994(Lab_1, Lab_2[, textiles]) Returns the difference $$\Delta E_{94}$$ between two given CIE L*a*b* colourspace arrays using CIE 1994 recommendation.

## CIE 2000

colour.difference

 delta_E_CIE2000(Lab_1, Lab_2[, textiles]) Returns the difference $$\Delta E_{00}$$ between two given CIE L*a*b* colourspace arrays using CIE 2000 recommendation.

## CMC

colour.difference

 delta_E_CMC(Lab_1, Lab_2[, l, c]) Returns the difference $$\Delta E_{CMC}$$ between two given CIE L*a*b* colourspace arrays using Colour Measurement Committee recommendation.

## Luo, Cui and Li (2006)

colour.difference

 delta_E_CAM02LCD(Jpapbp_1, Jpapbp_2) Returns the difference $$\Delta E'$$ between two given Luo et al. (2006) CAM02-LCD colourspaces $$J'a'b'$$ arrays. delta_E_CAM02SCD(Jpapbp_1, Jpapbp_2) Returns the difference $$\Delta E'$$ between two given Luo et al. (2006) CAM02-SCD colourspaces $$J'a'b'$$ arrays. delta_E_CAM02UCS(Jpapbp_1, Jpapbp_2) Returns the difference $$\Delta E'$$ between two given Luo et al. (2006) CAM02-UCS colourspaces $$J'a'b'$$ arrays.

## Li, Li, Wang, Zu, Luo, Cui, Melgosa, Brill and Pointer (2017)

colour.difference

 delta_E_CAM16LCD(Jpapbp_1, Jpapbp_2) Returns the difference $$\Delta E'$$ between two given Li et al. (2017) CAM16-LCD colourspaces $$J'a'b'$$ arrays. delta_E_CAM16SCD(Jpapbp_1, Jpapbp_2) Returns the difference $$\Delta E'$$ between two given Li et al. (2017) CAM16-SCD colourspaces $$J'a'b'$$ arrays. delta_E_CAM16UCS(Jpapbp_1, Jpapbp_2) Returns the difference $$\Delta E'$$ between two given Li et al. (2017) CAM16-UCS colourspaces $$J'a'b'$$ arrays.

## DIN99

colour.difference

 delta_E_DIN99(Lab_1, Lab_2[, textiles]) Returns the difference $$\Delta E_{DIN99}$$ between two given CIE L*a*b* colourspace arrays using DIN99 formula.

## Standardized Residual Sum of Squares (STRESS) Index

colour

 index_stress(d_E, d_V[, method]) Computes the Kruskal's Standardized Residual Sum of Squares (:math:STRESS) index according to given method. INDEX_STRESS_METHODS Supported $$STRESS$$ index computation methods.

colour.difference

 index_stress_Garcia2007(d_E, d_V) Computes the Kruskal's Standardized Residual Sum of Squares (:math:STRESS) index according to García, Huertas, Melgosa and Cui (2007) method.

## Huang et al. (2015) Power-Functions

colour.difference

 power_function_Huang2015(d_E[, coefficients]) Improves the performance of the $$\Delta E$$ value for given coefficients using Huang, Cui, Melgosa, Sanchez-Maranon, Li, Luo and Liu (2015) power-function: $$d_E^'=a*d_E^b$$.