Time localisation of surface defects on optical discs

Sometimes a compact disc player fails to operate when a disc with a scratch or a fingerprint is played. One way to improve the playability of discs with such defects, is to locate the defect in time and then handle it in a special way. This time localisation is needed to be rather accurate. Fang´s algorithm for segmentation of the time axis is used since it has good performance in an application like this. Fang´s algorithm has a clear potential for time localisation for some defects but not for other defects. The time location of these other defects is improved by using another method. The normally used threshold method is improved to handle skewness of the disc and to improve localisation of the end of the defect.