A method and apparatus for measuring hair in a predefined area of skin. The method addresses the preparation of the skin and the device for counting the hairs in a defined area. The apparatus contains an optical magnifying lens, a housing for the lens and an aperture of known surface area in order to...http://www.google.se/patents/US5331472?utm_source=gb-gplus-sharePatent US5331472 - Method and apparatus for measuring hair density
