Patent attributes
A hair-detection device with a source of electromagnetic radiation, an imaging sensor and a radiation selection means. The selection means improves a ratio between a part of emitted radiation that is coupled into a skin which reaches the sensor and thus provides an image of the skin, and the part that reaches the sensor via other ways, such as reflection at the skin surface. The radiation may have a wavelength between about 700 nm and 1100 nm. The radiation selection means may for example include a separate wall around at least one of the source and the sensor, such as crossed polarizers. By means of this selection, the contrast of the image may be improved, and may be made less dependent on skin color and skin artifacts, thus enabling easier detection of for example, white hairs on a fair skin.