Paul Salama | Search PubMed

PubMed2005

Error concealment for shape in MPEG-4 object-based video coding.

In asynchronus transfer mode networks, cell loss or channel errors can cause data to be dropped in the channel. When digital images/videos are transmitted over these networks, one must be able to reconstruct the missing data so that the impact of the errors is minimized. In this paper, we present an error-concealment technique for shape in MPEG-4 object-based video coding. This method, which is based on using global motion estimation and compensation techniques for boundary recovery, consists of three steps: (1) boundary extraction from shape; (2) boundary patching using global motion compensation; and (3) boundary filling to reconstruct the shape of the damaged video object planes. Global motion parameters are inserted as part of the USER_DATA field in the compressed stream and are utilized in reconstructing the damaged boundaries of compressed video object planes.

Algorithms↗

PubMed2005

Performing a colonoscopy 12 months after surgery for colorectal neoplasia.

BACKGROUND: There appears to be acceptance that following up patients after surgery for colorectal neoplasia is of value. However, specific issues relating to which investigations to perform and how often remain unresolved. The aim of this project was to evaluate the clinical utility of performing a colonoscopy 12 months after curative surgery for colorectal neoplasia. METHODS: Patients were selected if they had undergone a curative resection for colorectal neoplasia, and if they had had a completed colonoscopy prior to surgery. Study endpoints included: (i) compliance with follow up; (ii) the prevalence, total number, size, and histology of polyps; and (iii) identification of recurrent or metachronous cancer. RESULTS: The study group included 253 patients of mean age 69.7 years (SD 11.6) and a male : female ratio of 1.4:1.0. Colonoscopies were completed on 90% of patients at a mean of 1.1 years following surgery. A total of 149 polyps were identified in 30% of patients. On histology, 42% were tubular adenomas, 6% tubulo-villous adenomas, 7% were villous adenomas, and 37% were hyperplastic. Advanced adenomas were identified in 7.9% of patients (95% CI 4.8-12.1%). No recurrent or metachronous cancers were identified. CONCLUSION: We have observed a high prevalence of advanced adenomas in patients undergoing a 12-month, follow-up colonoscopy after curative surgery for colorectal neoplasia. The significance of these observations requires further evaluation.

Adenoma↗