Study of a new parameter used in objective measurement of skin erythema

摘要

The objective measurement of skin erythema is of much importance in clinical dermatological diagnosis and new dermatological drug tests. The measurements that used currently are facing a main problem that all the measurements are deeply influenced by the melanin in the epidermis and the incident intensity. Basing on the skin optical model, a new parameter is introduced in order to describe the change of erythema. The new parameter is defined by the difference of the logarithm of the diffuse reflected light intensity between normal skin and erythema skin. The theoretical analysis shows that this new parameter can reflect directly the deviation of the concentration of haemoglobin from the normal range under the assumption of keeping the concentration of melanin constant and the illuminating light uniform. In addition, the experimental study also shows that this method is hardly influenced by the illuminating light intensity, and can be effectively applied in the clinical diagnosis.