in the information age, the protection of the right to privacy has evolved to issues related to the collection, use, and dissemination of personal data in information systems, particularly with regard to the image in video surveillance. Therefore it takes a technique or tool to protect and maintain the privacy of people, so it is not abused by people who are not responsible. To achieve this goal, many approaches have been proposed using algorithms and filters that are applied directly to the system. With so many developments in research in this field, this paper provides a comparison of several existing methods comprehensively through the classification with their respective weaknesses and advantages. In addition, examples of some techniques are used visually, so as to get a complete picture of this method of privacy protection.