The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Super-resolution reconstruction produces high-resolution images from a set of low-resolution images of the same scene. In the last two and a half decades, many super-resolution algorithms have been proposed. These algorithms are usually very sensitive to their assumed models of data and noise, and also computationally expensive for many practical applications. In this paper we adopt computationally...
In this paper a context based super-resolution (SR) image reconstruction method is proposed. The proposed maximum a-posteriori (MAP) based estimator identifies local gradients and textures for selecting the optimal SR method for the region of interest. Texture segmentation and gradient map estimation are done prior to the reconstruction stage. Gradient direction is used for optimal noise reduction...
A wavelet based compressed sensing super resolution algorithm is developed, in which the energy function optimization is approximated numerically via the regularized orthogonal matching pursuit. The proposed algorithm works well with a smaller quantity of training image patches and outputs images with satisfactory subjective quality. It is tested on classical images commonly adopted by super resolution...
A novel algorithm for super resolution (SR) in images and video sequences is introduced. In difference with conventional approaches, new framework employs the spatial spectral properties of an image or sequence applying wavelet technique. Novel wavelets based on atomic functions used in SR have shown good properties of resolution by extension of an image size up to 4 times in comparison with the original...
Noise is inevitably introduced to medical images because of various factors in medical imaging. The noise in medical images degrades the quality of images, blurring boundaries and suppressing structural details, thus bring difficulties to medical diagnosis. Therefore, the key to medical image de-noising is to remove the noise while preserving important features. In this paper, we analyze and compare...
In this paper, we propose a fast multi-layer motion estimation algorithm for spatial scalability provided in H.264/AVC scalable extension, based on the reuse of the motion vectors from multiple spatial layers. The reused motion vector is used to set a search center and refined within a small search area. However, the reused motion vector often produces significant prediction error at object boundaries...
A kurtosis-based super-resolution image reconstruction algorithm is proposed in this paper. Firstly, we give the definition of the kurtosis image and analyze its two properties: (i) the kurtosis image is Gaussian noise invariant, and (ii) the absolute value of a kurtosis image becomes smaller as the the image gets smoother. Then we build a constrained absolute local kurtosis maximization function...
Motion estimation process is the most computational and memory intensive component in video encoders. However, traditional motion estimation algorithms focus on rate and distortion performance and do not take memory bandwidth into consideration. As a result, its performance will be degraded under bandwidth constraint environment. In this paper, a bandwidth-rate-distortion optimized motion estimation...
With the advent of new video standards such as H.264/AVC, the demands for low-complexity advanced video coding (AVC), particularly for the subfunction of variable block searching motion estimation, is increasingly important for efficient system designs. The motion estimation needs heavy computations and many external memory accesses which are the main sources of the system complexity and power consumption...
In this paper, we propose a novel learning-based video super resolution algorithm with less memory requirements and computational cost. To this end, we adopt discrete cosine transform (DCT) coefficients for feature vector components. Moreover, we design an example selection procedure to construct a compact database. We conducted evaluative experiments using MPEG test sequences to synthesize a high...
This paper proposed a superresolution (SR) reconstruction method by combining the cross-diamond-hexagonal search (CDHS) block-matching algorithm (BMA) and the simple block-wise motion vector selection (BWMVS) strategy to obtain stable and high quality reconstruction results. The experimental results showed that the reconstruction quality of CDHS BMA is comparable with full search BMA but the computation...
When video packets are lost in congested networks, one loss pattern creates a different visual impact than another. We conduct a subjective experiment with H.264 videos and conclude that isolated losses are better than bursty losses in terms of perceptual video quality. A network-implementable video quality model is developed for a router to drop packets so as to achieve good visual quality.
Super-resolution (SR) of facial images from video suffers from facial expression changes. Most of the existing SR algorithms for facial images make an unrealistic assumption that the "perfect" registration has been done prior to the SR process. However, the registration is a challenging task for SR with expression changes. This paper proposes a new method for enhancing the resolution of...
In this paper, we propose a joint coding scheme for both multi-view video and its corresponding depth map. After we synthesize a virtual image for the target view using adjacent view images and their depth information, we apply a view interpolation prediction (VIP) method for both multi-view video coding and its depth data coding. In order to improve the synthesized virtual view, we also propose a...
In this paper, we propose a new super resolution method Maximum a Posteriori based on a universal hidden Markov tree model (MAP-uHMT) for remote sensing images. The hidden Markov tree theory in the wavelet domain is used to set up a prior model for reconstructing super resolution images from a sequence of warped, blurred, sub-sampled and contaminated low resolution images. Both the simulation results...
In this paper, a simple block-wise motion vector selection (BWMVS) strategy was incorporated into the motion estimation algorithm. The occlusion that severely damages the quality of the reconstructed video sequence in superresolution (SR) problem is effectively removed. The stability due to the BWMVS could be seen from the reconstruction results in comparison with the standard interpolation.
The temporal correlation between adjacent video frames poses a severe challenges for video watermarking applications. Motion-coherent watermarking has been recognized as a strategy to embed watermark information in video frames, resistant to collusion attacks. The motion-compensated temporal wavelet transform (MC-TWT) provides an efficient tool to separate static and dynamic components of a video...
Video frame rate up conversion (FRUC) has many applications, especially it has been proved to effectively reduce the motion blur problem and improve the visual quality on LCD. In this paper, we propose a global-to-local iterative algorithm to resolve the problems occurring in the existing block based algorithms. In addition, the iterative approach, where interpolated blocks are generated in confident...
Watermarking is used for copyright protection using logo, image, stamp and text as a watermark. Recently, especially embedding binary image to color images has been worked alot and gave very promising results. In this work, we used text with small size characters and embed to color image as an image. We used discrete wavelet transform to embed partions of watermark to different frequency bants of...
In general, all the video super-resolution (SR) algorithms present the important drawback of a very high computational load, mainly due to the huge amount of operations executed by the motion estimation (ME) stage. Commonly, there is a trade-off between the accuracy of the estimated motion, given as a motion vector (MV), and the computational cost associated. In this sense, the ME algorithms that...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.