Validation of segmentation techniques for digital dermoscopy.
OBJECTIVE
This study aims at evaluating two automatic contour detection techniques especially developed for dermoscopic images.


METHODS
Twenty-five images of lesions with a fuzzy boundary have been randomly selected. Five dermatologists experienced in dermoscopy have manually drawn the border of all the lesions and repeated the procedure after two and four weeks. The ability of a dermatologist to reproduce its own results was evaluated by measuring the non-overlapping area enclosed by its three successive contours. The interobserver variability evaluated the contour accuracy when using automatic or manual drawings. The mean probability that a pixel has been misclassified was computed for every observer and automatic technique.


RESULTS
Experts in dermoscopy are not able to reproduce measurements precisely and the two automatic techniques had a lower misclassification probability than those obtained by each dermatologist.


CONCLUSIONS
This study demonstrates that a single dermatologist should not be used as a reference, and subjective validation of lesion contour is inaccurate outside an experts's group. It is argued that image processing techniques for computer-aided diagnosis must show the best compromise within such a group.
Joel
Guillod
G
Department of Dermatology, University Hospital of Western Switzerland (Lausanne and Geneva), DHURDV, Switzerland. joel.guillod@net2000.ch
Schmid-Saugeon
Philippe
P
Guggisberg
David
D
Cerottini
Jean Philippe
JP
Braun
Ralph
R
Krischer
Joakim
J
Saurat
Jean-Hilaire
JH
Murat
Kunt
K
D000465:Algorithms; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D006801:Humans; D012871:Skin Diseases / Q000473:pathology*; D012880:Skin Pigmentation