Surveillance systems refer to the collection, monitoring, and analysis of data and information for the purpose of preventing, detecting, and responding to security threats, criminal activities, or other risks. These systems typically involve the use of various technologies such as cameras, sensors, and monitoring software to gather and analyze data in real-time. Surveillance systems can be used in a wide range of environments, including public spaces, transportation systems, commercial facilities, and residential areas. They are often used by law enforcement agencies, security companies, and government organizations to enhance public safety and security. Some common applications of surveillance systems include video surveillance for monitoring and recording activities, access control systems for restricting entry to secure areas, and alarm systems for detecting and responding to unauthorized intrusions. Overall, surveillance systems play a critical role in helping to prevent and respond to security threats and criminal activities in various settings.