Study Of The Image Enhancement Methods On Video Monitoring System

With the rapid development of network, communications, image processing, microelectronics technologies and improvement of people's material living standards, video monitoring with its intuitive, user-friendly and content-rich features attracts people's increasing attention. But because of the immaturity of network video processing technology and intelligent video analysis technology, video data compression, transmission and storage generally apply to video monitoring system for the moment. The video monitoring image quality effects on monitoring system directly. So how to use video image enhancement methods on video monitoring system to make the system work fast and efficiently are worth topics.Because video monitoring system images usually have defects such as poor contrast, fuzzy edge and large noise, it brought many negative effects to use digital video. So the study of videos enhanced treatment is a meaningful job.In this paper, digital video monitoring system compression coding technology was researched. The research focus was compressed video images enhancement from two aspects which were video noise reduction and contrast enhancement.The main works of thesis include:Video monitoring system, video coding and decoding technology were introduced. By comparing H.26x and MPEG standards, in particular the current research focus MPEG-4 and H.264 coding standards, the conclusion that H.264 standard is more suitable for digital video monitoring system was reached. So H.264 was used in video image compression, and overview of the key technology and applications of H.264 were provided.H.264 was used to compress video which acquired by monitoring system. Quantification is the only module which results in loss in compressing process. RBF neural network was used to predict quantification parameters and quality of video was effectively improved.In respect of video contrast enhancement, aiming at low contrast of video monitoring image, methods to improve contrast such as histogram amendment, weighted average and unsharp masking method based on wavelet transform were studied and realized. In respect of video noise reduction, intra-frame and inter-frame methods were studied. In respect of intra-frame method, neighborhood average method, Wiener filtering, Gaussian filtering and Butterworth filtering were researched and tested. In respect of inter-frame, average time-domain filtering and adaptive recursive filtering were researched. Aiming at spatial and temporal correlation of video monitoring images,intra-frame filtering and inter-frame filtering methods were combined to deal with video enhancement. The effectiveness and practicality of the algorithm were proved by theoretical analysis and practical experiments.The simulation interface was designed by DirectShow. Kinds of enhancement algorithms were integrated in it. And simulations of the enhancement algorithms were done on it.At last, sum-up and further research direction were given.