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Validation on 3D Surface Roughness Algorithm for Measuring Roughness of Psoriasis Lesion

Authors: M.H. Ahmad Fadzil, Esa Prakasa, Hurriyatul Fitriyah, Hermawan Nugroho, Azura Mohd Affandi, S.H. Hussein


Psoriasis is a widespread skin disease affecting up to 2% population with plaque psoriasis accounting to about 80%. It can be identified as a red lesion and for the higher severity the lesion is usually covered with rough scale. Psoriasis Area Severity Index (PASI) scoring is the gold standard method for measuring psoriasis severity. Scaliness is one of PASI parameter that needs to be quantified in PASI scoring. Surface roughness of lesion can be used as a scaliness feature, since existing scale on lesion surface makes the lesion rougher. The dermatologist usually assesses the severity through their tactile sense, therefore direct contact between doctor and patient is required. The problem is the doctor may not assess the lesion objectively. In this paper, a digital image analysis technique is developed to objectively determine the scaliness of the psoriasis lesion and provide the PASI scaliness score. Psoriasis lesion is modelled by a rough surface. The rough surface is created by superimposing a smooth average (curve) surface with a triangular waveform. For roughness determination, a polynomial surface fitting is used to estimate average surface followed by a subtraction between rough and average surface to give elevation surface (surface deviations). Roughness index is calculated by using average roughness equation to the height map matrix. The roughness algorithm has been tested to 444 lesion models. From roughness validation result, only 6 models can not be accepted (percentage error is greater than 10%). These errors occur due the scanned image quality. Roughness algorithm is validated for roughness measurement on abrasive papers at flat surface. The Pearson-s correlation coefficient of grade value (G) of abrasive paper and Ra is -0.9488, its shows there is a strong relation between G and Ra. The algorithm needs to be improved by surface filtering, especially to overcome a problem with noisy data.

Keywords: psoriasis, roughness algorithm, polynomial surfacefitting.

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[1] "Psoriasis",
[2] Neimann, A.L., Porter, S.B., Gelfand, J.M., "The Epidemiology of Psoriasis",, 2006
[3] Chang, C.C., Gangaram, H.B., Hussein, S.H., "Malaysian Psoriasis Registry - Prelimanary Report of a Pilot Study Using a Newly Revised Registry Form", Medical Jour.Malaysia Vol 63 C, Sept 2008.
[4] Blunt, L., Jiang, X., Advanced Techniquees for Assessment Surface Topography, Kogan Page Ltd, London, UK, 2003.
[5] Muralikrishnan, B., Raja, J., Computational Surface and Roundness Metrology, Springer-Verlag London Limited, UK, 2009.
[6] Whitehouse, D.J., Handbook of Surface Metrology, IOP Pub. 2003.
[7] Smalls, L.K., et. al, "Quantitative Model of Cellulite: Three Dimensional Skin Surface Topography, Biophysical Characterization and Relationship to Human Preception", Journal of Cosmetic Science, Vol. 56, No 2, 2005, pp. 105-120.
[8] Frankowski,G., Chen,M., "Optical 3D in vivo Measurement of Human Skin Surfaces with PRIMOS", Proc.of Fringe, 2001.
[9] G. Barbato, et. al, "Scanning tunneling microscopy methods for roughness and micro hardness measurements", Synthesis report for research contract with the European Union under its programme for applied metrology, European Commission Catalogue number: CD-NA- 16145 EN-C, Brussels, Luxemburg 1995.
[10] Loden, M., "Atopic Dermatitis and Other Skin Diseases", Bioengineering of The Skin: Skin Imaging and Analysis, Edited: K.P. Wilhelm et. al., Informa Healthcare USA, Inc, New York, 2007.
[11] Janoff, M.S., Hayhoe, G.F.,"The Development of a Simple Instrument for Measuring Pavement Roughness and Predicting Pavement Rideability", Association of Road Congresses Technical Committee on Surface Characteristics, ASTM International, 1990.
[12] "User Manual: PRIMOS Optical 3D Skin Measuring Device", GFMesstechnik GmbH, Germany, 2008.
[13] Hoffman, R., Krotkov E., "Terrain Roughness Measurement from Elevation Maps", SPIE Vol. 1195 Mobile Robots IV, 1998.
[14] "Triangle wave",
[15] Jong Sung Yoon, Cheolho Ryu , Jang Hyun Lee," Developable polynomial surface approximation to smooth surfaces for fabrication parameters of a large curved shell plate by Differetial Evolution", Computer-Aided Design 40 905-915, Elsevier, 2008.
[16] "Coefficient_of_determination",
[17] Dong, W.P, Mainsah, E., Stout, K.J., "Reference Plane for the Assessment of Surface Roughness in Three Dimensions", International Journal Mecahnical Tool Manufacturing, Vol. 35 No 2, Pergamon, 1995.
[18] Besl,J.P., Jain, R.C., "Three-Dimensional Object Recognition", Computing Surveys, Vol.17, No.1, March 1985
[19] Majumdar, A., Tien, C.L., "Fractal Characterization and Simulation of Rough Surfaces", Wear, Vol 136, Issue 2, March 1990, Elsevier, 1990