Using infrared radars for ear positioning in active noise control headrests

Active noise control headrests reduce low frequency noise around human ears based on active noise control technology, in which accurate positioning of human ears is required to achieve good noise reduction performance when the human head moves. In this paper, infrared radars are used in an active noise control headrest by installing them around the human head. Three infrared radars are used, which face the left, the right and the back sides of the human head separately in a horizontal plane. The location of each ear is estimated by searching the abnormal bulges from the scanned contour line of the human head. The positioning ability of the proposed system for both translating and rotating movements of human head and the improvement of noise reduction are investigated based on the experiment measurements. The effective range, positioning accuracy and the limitations of the proposed method are further discussed.