Sunday, April 3, 2005
Hall of Mirrors (Hilton Cincinnati Netherland Plaza)
Session: 1223, Graduate Student Poster Session, 3:00 PM

Quantifying Skin Color from Digital Images: An Innovative Technique

Rachel Baker, Predoctoral Student, College of Nursing, University of Cincinnati, PO Box 210038, Cincinnati, OH 45221-0038, Marilyn Sommers, PhD, RN, FAAN, Associate Dean, Nursing Research Division, University of Cincinnati, 3110 Vine Street, Cincinnati, OH 45221, and Jamison Fargo, PhD, Assistant Professor, Psychology, Utah State University, Department of Psychology, Logan, UT 84322.

Problem: The skin has been called the “primary interface” between patients and nurses. Nurses are involved in the evaluation of, and care for, patients’ skin. The analysis of skin color is relevant to the assessment of abrasions, tears, redness, and wounds. Skin color is quantified using subjective scales or objective reflectance spectrometers. The present study proposed a third method of skin color analysis that uses digital images taken to document and measure skin anomalies, injuries, and burns. Purpose: The present study examined the feasibility of quantifying skin color using digital images. Theoretical Framework: The Trichromatic Theory of Color Perception states that every color is a linear combination of the three primary colors. A standardized system of color classification, CIE L*(light-dark) a* (red-green) b*(yellow-blue), was developed from this theory. Design: Analysis of digital images taken of skin. Sample: Images of 52 subjects’ skin were analyzed (28 White and 24 Black subjects). Procedure: Using digital imaging software, two independent raters obtained CIE L*a*b* values. Results: Inter-rater reliabilities for L*, a*, and b* values among all subjects were: L: r=0.910, p=0.0001; a: r=0.897, p=0.0001; b: r=0.958, p=0.0001. The mean L* score for White subjects was 74.64 (SD=4.13) and for Black subjects was 50.44 (SD=8.65). The mean a* score for White subjects was 26.19 (SD=5.44) and for Black subjects was 16.72 (SD=7.58). The mean b* score for White subjects was 22.17 (SD=8.72) and for Black subjects was 15.38 (SD=11.84). The L*, a*, and b* values were significantly more variable among Black subjects than White subjects. Implication for nursing science: While this technique proved feasible and reliable, further validity work is needed. The metrics involved in this study have a wide application to scientists studying wounds and burns and to forensic nurses attempting to date injuries based on changes in skin color.

Session #1223 - Graduate Student Poster Session

The 29th Annual MNRS Research Conference (April 1-4, 2005)