Skip to main content

Research Repository

Advanced Search

Reflectance of human skin using colour photometric stereo: With particular application to pigmented lesion analysis

Sun, Jiuai; Smith, Melvyn; Smith, Lyndon; Coutts, Louise; Dabis, Rasha; Harland, Christopher; Bamber, Jeffrey

Authors

Jiuai Sun

Profile Image

Melvyn Smith Melvyn.Smith@uwe.ac.uk
Research Centre Director Vision Lab/Prof

Lyndon Smith Lyndon.Smith@uwe.ac.uk
Professor in Computer Simulation and Machine

Louise Coutts

Rasha Dabis

Christopher Harland

Jeffrey Bamber



Abstract

Background/purpose: The optical appearance of human skin is highly dependent on the interaction between the illumination (type and position), observer position and the skin surface structure. Different currently available photographic techniques record different aspects of this appearance, each providing its own incomplete description. This limits their usefulness, especially for pigmented skin lesion diagnosis. In this paper a new, easy to use, low-cost photographic method is described, which aims to generate an efficiently encoded yet reasonably complete representation of skin appearance. Material and methods: A prototype hand-held camera was developed that rapidly acquires six colour images, each with the skin illuminated from a different direction. A novel photometric stereo processing was used to combine these into a colour image of the skin's diffuse reflectance, independent of the skin surface topography, as well as a separate representation of that topography in the form of a surface gradient image. Images of four clinical pigmented skin lesions were evaluated in comparison with conventional digital photographs by both visual judgement and automated lesion boundary detection. Results: The new colour reflectance images were free from the effects of topographical shading, shadowing and specular reflections. Lesion boundaries obtained automatically from the reflectance images were always closer to the outline drawn by a dermatologist than those obtained from conventional photographs. Finally, recombining the colour reflectance and surface gradient data to form a virtual image of the skin surface that is highly realistic in appearance. Conclusions: The new colour photometric stereo camera produces images of skin and skin tumours in which the reflectance information that is related to subsurface pigment distribution is separated from the surface topographic information. The total information generated by the system, for use in visual or automated analysis, is potentially greater than that for either conventional photography or dermatoscopy alone. Its further development and broader clinical evaluation are warranted to determine its usefulness and role in a wide range of dermatological tasks, including tele-dermatology applications. © 2007 The Authors Journal compilation © 2007 Blackwell Munksgaard.

Citation

Sun, J., Smith, M., Smith, L., Coutts, L., Dabis, R., Harland, C., & Bamber, J. (2008). Reflectance of human skin using colour photometric stereo: With particular application to pigmented lesion analysis. Skin Research and Technology, 14(2), 173-179. https://doi.org/10.1111/j.1600-0846.2007.00274.x

Journal Article Type Article
Publication Date May 1, 2008
Journal Skin Research and Technology
Print ISSN 0909-752X
Electronic ISSN 1600-0846
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 14
Issue 2
Pages 173-179
DOI https://doi.org/10.1111/j.1600-0846.2007.00274.x
Keywords skin photography, reflectance, photometric stereo, colour, dermatoscopy, ABCD rule, skin lesions, automated diagnosis, tele-dermatology
Public URL https://uwe-repository.worktribe.com/output/1013170
Publisher URL http://dx.doi.org/10.1111/j.1600-0846.2007.00274.x