US Patent 9924875 Apparatus and methods for modifying keratinous surfaces

A method and device for analyzing and treating tonal imperfections on human skin. The method has the steps of taking at least one background image of at least 10 μm2 of skin and calculating the average background L value of the image on a grey scale. One or more treatment images of the skin are taken and at least one localized L value of individual pixels or group of pixels is calculated within the treatment image. The local L value is compared to the background L value. Skin deviations are areas of skin where the absolute value of the difference between a local L and the background L is greater than a predetermined ΔLS. Skin deviations are identified by this method and then treated with a treatment composition.