ABSTRACT
Psoriasis is an incurable but treatable skin disease and can exist for a long time [1]. The disease is characterized by an abnormally high growth rate of new skin cells. Under normal conditions, skin cells will grow in approximately twenty-eight days, but in psoriasis the growth can occur in four days [2]. Psoriasis is marked by the appearance of red lesions on body surfaces. At greater severities the lesion thickness increases, with coarse, slivery scales appearing. Psoriasis is not a contagious disease. Recent studies have shown that psoriasis can signicantly affect quality of life, with many psoriasis patients experiencing social and psychological problems [3]. The published psoriasis prevalence in Malaysia by the Dermatological Society of Malaysia is 3% [4]. Of the 75,883 patients registered in the Hospital Kuala Lumpur from 2005 to 2010, 3,906 psoriasis patients were registered in the
CONTENTS
2.1 Introduction on Psoriasis Erythema ......................................................... 51 2.2 Erythema Measurement .............................................................................53 2.3 Development of the PASI Erythema Classication ................................. 59
2.3.1 Fuzzy c-Means (FCM) Clustering for Erythema Scoring .......... 59 2.3.2 Skin Tone Classication ..................................................................64 2.3.3 Erythema Score Classication ....................................................... 67
2.4 Agreement Analysis of PASI Erythema ...................................................72 2.5 Conclusion .................................................................................................... 74 Appendix: Matlab Code ....................................................................................... 74
FCM Training Stage ..................................................................................... 74 FCM Classication ....................................................................................... 78
References ...............................................................................................................84
Dermatology Department, resulting in an incidence of 5.2% [5]. Several examples of red plaques of psoriasis lesions and erythema severity levels are depicted in Figure 2.1.
