An adaptive edge model in the wavelet domain for wavelet image coding

State-of-art wavelet coders owe their performance to smart ideas for exploiting inter and intra-band dependencies of wavelet coefficients. We claim that developing more efficient coders requires us to look at the main source of these dependencies; i.e., highly localized information around edges. This paper investigates the structural relationships among wavelet coefficients based on an idealized view of edge behavior, and proposes a simple edge model that explains the roots of existing dependencies. We describe how the model is used to approximate and estimate the significant wavelet coefficients. Simulations support its relevance for understanding and analyzing edge information. Specifically, model-based estimation within the space-frequency quantization (SFQ) framework increases the peak signal-to-noise ratio (PSNR) by up to 0.3dB over the original SFQ coding algorithm. Despite being simple, the model provides valuable insights into the problem of edge-based adaptive modeling of value and location information in the wavelet domain

AUTOMATED DETECTION OF REFUGEE DWELLINGS FROM SATELLITE IMAGERY USING MULTI-CLASS GRAPH-CUT SEGMENTATION AND SHADOW INFORMATION

22nd IEEE Signal Processing and Communications Applications Conference (SIU) -- APR 23-25, 2014 -- Karadeniz Teknik Univ, Trabzon, TURKEYWOS: 000356351400377This paper adresses the automated detection and enumeration of the dwellings/tents within the refugee camp areas using satellite and aerial images. The fact that dwellings inside the refugee camps correspond to very small, densely and sometimes arbitrarily positioned objects that are hard to distinguish from the background, even in Very-High Resolution (VHR) images, makes the automated tent/dwelling detection a difficul problem. In this paper, a method combining the use of the multi-class graph-cut segmentation and shadow information is proposed for dwelling/tent detection. Accordingly, as a first step, tents/dwellings are detected by applying graph-cut segmentation and morphology. Then, in order to improve the accuracy, the shadow information is exploited. At the last step, all detected tent segments are re-checked for correctness using a gradient-based thresholding method. The proposed method is tested on the images of the refugee camps that mostly have arbitrary and dense dwelling/tent positioning inside. The precision and recall values are determined to evaluate the performance. The obtained average precision (91.9N and average recall (90.0%) performances are promising considering the difficulty of the problem.IEEE, Karadeniz Tech Univ, Dept Comp Engn & Elect & Elect Eng

Low recurrence rate of hepatocellular carcinoma following ledipasvir and sofosbuvir treatment in a real-world chronic hepatitis C patients cohort

WOS: 000469027000006PubMed ID: 30740820The aims of the present study were to evaluate the efficacy and tolerability of ledipasvir/sofosbuvir (LDV/SOF) with or without ribavirin in the treatment of chronic hepatitis C (CHC) in patients with advanced liver disease and to analyse whether the use of LDV/SOF treatment is associated with a new occurrence of hepatocellular carcinoma (HCC) during and after LDV/SOF treatment. The Turkish Early Access Program provided LDV/SOF treatment to a total of 200 eligible CHC patients with advanced liver disease. The median follow-up period was 22months. All patients were Caucasian, 84% were infected with genotype 1b, and 24% had a liver transplantation before treatment. The sustained virological response (SVR12) was 86.0% with ITT analysis. SVR12 was similar among patients with Child-Pugh classes A, B and C disease and transplant recipients. From baseline to SVR12, serum ALT level and MELD score were significantly improved (P<0.001). LDV/SOF treatment was generally well tolerated. Only one patient developed a new diagnosed HCC. Seventeen of the 35 patients, who had a history of previous HCC, developed HCC recurrence during the LDV/SOF treatment or by a median follow-up of 6months after treatment. HCC recurrence was less commonly observed in patients who received curative treatment for HCC compared with those patients who received noncurative treatment (P=0.007). In conclusion, LDV/SOF with or without ribavirin is an effective and tolerable treatment in CHC patients with advanced liver disease. Eradication is associated with improvements in liver function and a reduced risk of developing a new occurrence of HCC. Ledipasvir and sofosbuvir with or without ribavirin is an effective and tolerable treatment in hepatitis C virus-infected patients with advanced liver disease. Eradication is associated with improvements in liver function and reduces the risk of developing a new occurrence of hepatocellular carcinoma