A Research Of Multifunctional Timing Surveillance System

With increasingly expanding electrical equipment and property at home and small office systems, safety precautions and fire monitoring has been considered to be an important issue for a modern home and small office systems. Large buildings have building automation devices, while small office systems or family basically have no prevention and control system. In order to meet the requirements for small office systems and home security and fire protection, this paper study and realize the multi-purpose microcomputer-based timing surveillance system. The proposed system has many virtues like good portability, low cost and easy installation.The article is discussed from both the hardware and software aspects, and put forward the basic structure of hardware and principle components of software systems. The hardware system is composed by 6 parts: MCU, image acquisition, human-computer interface, external storage and calendar / time reading, writing and communication interfaces. And software has five parts: feature extraction module, job control module, operator interface, the clock module and communication module. The system's core module is feature extraction module, which can achieve two functions- moving object monitoring and fire monitoring. Through monitoring the moving objects, suspicious anomalies can be found. To compensate the small MCU memory space and its slow processing speed, the paper proposes two kinds of algorithms to achieve a moving object monitoring. One is Sobel edge detection, and the other is inter-frame difference method. As to fire monitoring, the inter-frame difference method can achieve this goal. Sobel based edge detection algorithm first conducts object extraction and screening of each frame on the region, de-noises with 8 neighborhood search method, and then compares two consecutive images of objects in the outline to find changes in the region and to determine whether there is object motion. The inter-frame difference method based algorithm obtains the difference image of the two consecutive input image, conducts the binarization, and then determine whether there are objects in the image trajectory by eight neighborhood fast-scanning method, thus to determine the movement of objects. The average intensity value of the 5 consecutive images can be calculated by a inter-frame difference method based fire monitoring algorithm. If changes in the average intensity of the value is relatively small, the monitored system is considered no fire and the algorithm ends; otherwise the system conduct subtraction and median filter denoising for continuous frames images. Threshold intensity is obtained using the instantaneous time value changes, finally difference image intensity change distribution is counted to determine whether there is a fire phenomenon.In order to facilitate the monitoring function of the system for users to set and query, the system needs to store and manage a lot of timing information and exceptions. Reminding time information is managed through the system calendar clock module. The management module follows the principle of minimizing data movement and processing time of MCU and designs dual-address based mapping mechanism to store, search, delete, add and edit information of timing alerts. Dual-address mapping mechanism does not require a large number of moving or empty data in reminding operation and thus save the time for mobile or empty data processing, rendering certain advantages for applications in single-chip system.This monitoring system and the proposed algorithm have passed through functional tests. Test results show that the system not only enables monitoring of moving objects and fire, but also is low in algorithm's time and space complexity, showing a certain significance in practical applications.