ABSTRACT
CONTENTS 13.1 Introduction ..................................................................................... 420 13.2 PH2 Database................................................................................... 421
13.2.1 Manual Segmentation of the Skin Lesion............................. 423 13.2.2 Clinical Diagnosis................................................................. 424 13.2.3 Dermoscopic Criteria ........................................................... 425
13.2.3.1 Asymmetry............................................................ 425
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13.2.3.2 Colors .................................................................... 425 13.2.3.3 Pigment Network................................................... 425 13.2.3.4 Dots/Globules ....................................................... 426 13.2.3.5 Streaks................................................................... 426 13.2.3.6 Regression Areas ................................................... 426 13.2.3.7 Blue-White Veil .................................................... 427
13.3 Dermoscopy Image Analysis............................................................. 427 13.3.1 Image Segmentation............................................................. 427
13.3.1.1 Gradient Vector Flow (GVF) Background ............ 428 13.3.1.2 Automatic Snake Initialization.............................. 429 13.3.1.3 Segmentation Results ............................................ 432
13.3.2 Color Labeling ..................................................................... 433 13.3.3 Melanoma Detection ............................................................ 435
13.4 Conclusions....................................................................................... 437 Acknowledgments ...................................................................................... 438 References .................................................................................................. 438
13.1 INTRODUCTION Skin cancer represents a serious public health problem because of its increasing incidence and subsequent mortality. Among skin cancers, malignant melanoma is by far the most deadly form. Because the early detection of melanoma significantly increases the survival rate of the patient, several noninvasive imaging techniques, such as dermoscopy, have been developed to aid the screening process [1]. Dermoscopy involves the use of an optical instrument paired with a powerful lighting system, allowing the examination of skin lesions in a higher magnification. Therefore, dermoscopic images provide a more detailed view of the morphological structures and patterns than normally magnified images of the skin lesions [1, 2]. However, the visual interpretation and examination of dermoscopic images can be a time-consuming task and, as shown by Kittler et al. [3], the diagnosis accuracy of dermoscopy significantly depends on the experience of the dermatologists. Several medical diagnosis procedures have been introduced in order to guide dermatologists and other health care professionals, for example, pattern analysis, the ABCD rule, the 7-point checklist, and the Menzies method. A number of dermoscopic criteria (i.e., asymmetry, border, colors, differential structures) have to be assessed in these methods to produce the final clinical diagnosis. However, the diagnosis of skin lesions is still a challenging task, even using these medical procedures, mainly due to the subjectivity of clinical interpretation and lack of reproducibility [1, 2].
