Determination of Skin Repigmentation Progression

Abstract

In this paper, we describe an image processing scheme to analyze and determine areas of skin that have undergone repigmentation in particular, during the treatment of vitiligo. In vitiligo cases, areas of skin become pale or white due to the lack of skin pigment called melanin. Vitiligo treatment causes skin repigmentation resulting in a normal skin color. However, it is difficult to determine and quantify the amount of repigmentation visually during treatment because the repigmentation progress is slow and moreover changes in skin color can only be discerned over a longer time frame typically 6 months. Here, we develop a digital image analysis scheme that can identify and determine vitiligo skin areas and repigmentation progression on a shorter time period. The technique is based on principal component analysis and independent component analysis which converts the RGB skin image into a skin image that represent skin areas due to melanin and haemoglobin only, followed by segmentation process. Vitiligo skin lesions are identified as skin areas that lack melanin (non-melanin areas). In the initial studies of 4 patients, the method has been able to quantify repigmentation in vitiligo lesion. Hence it is now possible to determine repigmentation progression objectively and treatment efficacy on a shorter time cycle.

Multimodal digital color imaging system for facial skin lesion analysis

“…12 Recently, Nugroho et al introduced an image analysis method that quantify vitiligo lesion in terms of image segmentation. 20 However, vitiligo can not be quantified only with area information because the cycling of 6-BH 4 is impaired in the vitiligo, leading to time-dependent accumulation of 7-BH 4 in the vitiligo, so that the concentrations of 6-and 7-biopterins are increased as a result of photo-oxidation process; that is, during improvement, the vitiligo area can be consistent while the concentration of the biopterins, which are the prominent endogenous fluorophores in vitiligo lesion, can be decreased. 15,[17][18] To verify the fact, we evaluated vitiligo lesion with UV-A radiation and demonstrated that quantitative and clinical meaningful analysis can be achieved with 2-D profiling of the biopterins distribution ( Fig.…”

Multimodal facial color imaging modality for objective analysis of skin lesions

“…Recently, Nugroho et al 36 proposed an image analysis method that measured the area of vitiligo lesions based on image segmentation, in order to evaluate the repigmentation progression. However, vitiligo cannot be quantified only by considering its area because the cycling of 6-BH 4 can be impaired in vitiligo lesions, leading to time-dependent accumulation of 7-BH 4 .…”

Evaluation of Non-Invasive Multispectral Imaging as a Tool for Measuring the Effect of Systemic Therapy in Kaposi Sarcoma

“…Using PCA for extracting blood and melanin values has been proposed [26], showing that skin color in digital RGB images can be described by the first two principal components. PCA and independent component analysis (ICA) have also been applied to RGB imaging data for extraction of blood and melanin values in vitiligo lesions to qualitatively evaluate the skin re-pigmentation progression [27], [28]. Our group has shown previously [29] that PCA applied to multispectral images from the skin in the wavelength range between 750 nm and 850 nm can be used for mapping the blood volume and blood oxygenation, where the first eigenvector (first principal component) describes the blood volume and the second eigenvector corresponds to the blood oxygenation.…”