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Image sharpness is an important aspect of image quality. It used to measure the degree of focus at the time of image acquisition. It also play an important role for video compression. Here, one new sharpness algorithm based on gradient shape is introduced in this paper. which is used for no-reference Image .The algorithm gets region of Interest in image firstly, then search the edge which can present...
Evaluation of community detection algorithms is very important to ensure both accuracy and quality of identified communities. Measuring quality incorporates edges, while measuring accuracy involves node labels. Due to this fundamental difference between accuracy and quality, often the evaluation process confronts with the issues such as trade-off between the two. In addition, real world networks such...
When applying a filter to an image, it often makes practical sense to maintain the local brightness level from input to output image. This is achieved by normalizing the filter coefficients so that they sum to one. This concept is generally taken for granted, but is particularly important where nonlinear filters such as the bilateral or and non-local means are concerned, where the effect on local...
Banding is a common video artifact caused by compressing low texture regions with coarse quantization. Relatively few previous attempts exist to address banding and none incorporate subjective testing for calibrating the measurement. In this paper, we propose a novel metric that incorporates both edge length and contrast across the edge to measure video banding. We further introduce both reference...
Exemplar-based methods have shown their potential in synthesizing novel but visually plausible contents for image super-resolution (SR), by using the implicit knowledge conveyed by the exemplar database. In practice, however, it is common that unwanted artifacts and low quality results are produced due to the using of inappropriate exemplars. How are the “right” exemplars defined and identified? This...
This paper proposes a CNN-based retrieval framework that uses Siamese network to learn a CNN model for image feature extraction. Model training and testing stages often use the same similarity metric. But this paper adopts a contrastive loss function with different distance metrics to fine-tune a pre-trained CNN model, and applies different distance metrics in testing stage. Through experimenting...
Normal human brain exhibits approximately bi-fold symmetry with respect to its midsagittal plane (MSP). The objective of this work is to investigate the effect of doubling atlases (i.e., reference images) used in multi-atlas fusion methods by exploiting the inherent bilateral symmetry of human brain. To this end, we perform automated segmentation of 15 subcortical structures using Local Weighted Voting...
Finding frequent patterns is an important problem in data mining. We have devised a method for detecting frequent patterns in event log data. By representing events in a graph structure, we can generate clusters of frequently co-occurring events. This method is compared with basic association mining techniques and found to give a “macro-level” overview of patterns, which is more interpretable. In...
Today iris recognition systems are extensively used for security and authentication purposes due to their simplicity and high reliability. But these systems face a major challenge of being spoofed by high quality printed iris images or pictures captured by camera. The problem is aggravated by use of varying illumination conditions in an attack access attempt. This paper investigates spoofing attempts...
In this Letter, we present a simple yet effective no-reference image blur assessment algorithm based on local total variation. Firstly, we calculate a local image blurriness metric by total variation. Then, the average of the largest 1% local total variation is computed. Finally, we obtain the blur score via a five-parameter logistic regression. The performance of the proposed algorithm is evaluated...
Along with the development of high resolution observation system, the spatial resolution of remote sensing images increases greatly. As it comes to the effective intelligent interpretation of high spatial resolution remote data, the traditional way of per-pixel processing is hardly applicable. On the other hand, the Object-Oriented method has shown its necessity and advantage, that is, grouping contiguous...
In addition to the texture, multiview video employs the utilization of depth coding for the reconstruction of 3D video and Free viewpoint video. Standing on some texture-depth correlations, a number of methods in literature reuses texture motion vector for the corresponding depth coding to reduce encoding time by avoiding costly motion estimation process. However, texture similarity metric is not...
Image sharpness is one of the most determining factors for image readability and scene understanding. How to accurately quantify it is a hot topic. This paper systematically validates a previously proposed index for full-reference image sharpness assessment (edge preservation ratio, EPR). Based on Gaussian blurring images in LIVE, CSIQ, TID2008 and TID2013 databases, we firstly evaluated EPR accuracy...
In this paper, we propose a medical image retrieval scheme which could be of immense help to the medical practitioners. Large collection of medical images are derived from various sources like X-rays, CT scan, PET scan, ultrasound, MRI etc and are available in different contexts. The real challenge then is the accessibility to such a database and retrieval of the relevant images in a quick time which...
Communities play an important role in the field of graph structure, especially in domains of networks analysis. A community (also referred to as a cluster) is a dense subgraph of the whole graph with more links between its members than between its members to the outside nodes. Communities overlap when nodes in graph belongs to multiple communities. Overlapping community detection is developing in...
In this paper, two image quality metrics based on morphological multiscale decompositions have been applied for the evaluation of free viewpoint video sequences. These sequences are synthesized using decompressed depth maps in the Depth-Image-Based Rendering synthesis process. Since the synthesis introduces edge distortion in the synthesized image/video, morphological filters are used for their ability...
The seminal works by Karger [13], [14] have shown that one can use Uniform Random Edge (URE) sampling to generate a graph skeleton which accurately approximates all cut-values in the original graph with high probability under some specific assumptions. As such, the random subgraphs resulted from URE sampling can often be used as substitutes for the original graphs in cut/flow-related graph-optimization...
Interactive image segmentation is able to extract the user-specified foreground objects from the whole image, which remains to be a challenging problem in image processing and computer vision. The traditional pixel-based interactive segmentation is time-consuming and neglects the neighbor information, which is hard to achieve efficient and accurate results. To address this problem, a novel region-based...
The real-time information on the Web changes dynamically and surge quickly, which cause considerable difficulty in access to interested information. How to mine hot events, how to analyze the correlation of events and how to organize information structurally are challenging tasks. In this paper, to address these problems, we propose STeller, an approach to mine context-aware story — a series of correlated...
We propose a fast technique for concealment of transmission errors in images. Corrupted regions are restored by texture extrapolation from the surrounding regions logically associated through image segmentation. Areas in the image containing unsharp edges or gradients, which are difficult to segment properly, are the main problem producing artefacts in the result. Therefore, our approach utilizes...
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