Exploring the CIEDE2000 thresholds for lightness, chroma, and hue differences in dentistry
María Tejada-Casado, Luis Javier Herrera, Francisco Carrillo‐Pérez, Javier Ruiz‐López, Razvan Ghinea, María del Mar Pérez Gómez
Abstract
• ΔL 00 PT 00 = 1.04; ΔC 00 PT 00 = 1.58 and ΔL 00 AT 00 = 2.82; ΔC 00 AT 00 = 3.04. • A significant difference was found between ligtness and chroma metrics. • No differences for ΔL 00 and ΔC 00 PT 00 were found between males and females groups. • A significant difference was found between CIEDE2000(1:1:1) and CIEDE2000(2:1:1). • H and C mismatch are more difficult to be accepted in de in dental color space. To evaluate the perceptibility and acceptability CIEDE2000 ( K L :K C :K H ) thresholds for lightness, chroma and hue differences in dentistry. A Python-based program was developed to conduct a psychophysical experiment based on visual assessments of computer-simulated images of human teeth. The experiment was performed on a calibrated display. A 40-observer panel: dentists and laypersons (male and female; n=10), evalu- ated three subsets of simulated human teeth: the lightness subset (%∆ L 00 ≥ 98 %), the chroma subset (%∆ C 00 ≥ 98 %) and the hue subset (%∆ H 00 ≥ 98 %), using ∆ E 00 ≥ 5 units. A Takagi-Sugeno-Kang Fuzzy Approximation model was used as fitting procedure, and 50:50 % lightness, chroma and hue CIEDE2000 (1:1:1) and CIEDE2000 (2:1:1) perceptibility ( PT 00 ) and accept- ability ( AT 00 ) thresholds were calculated. Data was statistically analyzed using t-test ( p < 0 . 05). The 50:50 % PT 00 for K L =1 were ∆ L 00 =1 . 04, ∆ C 00 =1 . 58 and ∆ E 00 =1 . 01; and for K L =2 were ∆ L 00 =0 . 51, ∆ C 00 =1 . 58 and ∆ E 00 =0 . 71. The 50:50 % AT 00 for K L =1 were ∆ L 00 =2 . 82, ∆ C 00 =3 . 04 and ∆ E 00 =2 . 66; and for K L =2 were ∆ L 00 =1 . 40, ∆ C 00 =3 . 04 and ∆ E 00 =1 . 78. PT 00 and AT 00 ∆ H 00 may be considered no computable. A significant difference was found between CIEDE2000(1:1:1) and CIEDE2000(2:1:1), between lightness and chroma metrics, and between observer groups. No differences for lightness and chroma PT 00 were found between male and female groups. It is important to use PT 00 and AT 00 for lightness, chroma and hue specific to evaluate perceptual sensitivity for color changes in the tooth color space. AT 00 for lightness and chroma are influenced by the observer's experience and gender. Males and laypersons show more tolerance for changes in chroma (∆ C 00 ) and in lightness (∆ L 00 ). Hue and chroma mismatch are more difficult to be accepted in dental color space.