Spatial Scalable Region of Interest Transcoding of JPEG2000 for Video Surveillance

A new method for spatial scalable region of interest transcoding of JPEG2000 images for video surveillance applications is proposed in this paper. The method transcodes HD images into quarter HD images with a ROI in HD resolution. The transcoding method is based on the precinct feature as well as on the empty packet feature of the JPEG2000 standard. Based on a user defined ROI the transcoder extracts all packets which belong to the ROI or to the lower resolution of the background. All non-ROI packets of higher resolution levels are deleted and replaced by empty-packets. Thus, the extracted codestream contains no high frequency information for image regions outside the ROI. Because the transcoder operates on packets and not on codeblocks an expensive re-encoding of the codestream is not required. This leads to a short processing time and a low complexity of the transcoding algorithm. Therefore, our method is appropriate for real-time applications like video surveillance.