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We propose a pseudo-sequence-based scheme for light field image compression. In our scheme, the raw image captured by a light field camera is decomposed into multiple views according to the lenslet array of that camera. These views constitute a pseudo sequence like video, and the redundancy between views is exploited by a video encoder. The specific coding order of views, prediction structure, and...
Sparse coding provides an excellent image prior for hyperspectral images (HSIs) denoising. However, on one hand, it is challenging to capture the structure within each sparse code for improving the reconstruction accuracy, on the other hand, the inconsistent recovery of the sparse codes corrupts the spectrum similarity in each homogeneous cluster of the HSI. To address these problems, we first propose...
Compressed sensing MRI (CS-MRI) and compressed sensing sensitivity encoding (CS-SENSE) only include two regularization items, total variation (TV) and Wavelet, which leads to artifacts remaindering in 1-D random sampling. In order to improve the performance of them, a new regularization item-Contourlet is introduced to constrain the solution with the other two regularization items together. The solution...
Standard sparse representations, applied independently to a set of overlapping image blocks, are a very effective approach to a wide variety of image reconstruction problems. Convolutional sparse representations, which provide a single-valued representation optimised over an entire image, provide an alternative form of sparse representation that has recently started to attract interest for image reconstruction...
Holography is an emerging technology to represent and display visual information and the associated experience expectations on the layman imaginary are huge. A hologram is a reproduction of a light field represented through the interference pattern between two wavefields, the reference and object wavefields. Holograms may be optically generated from real objects or computationally generated from synthetic...
For low bit rate scenarios (video conferencing, aerial surveillance), conventional video coding is unable to meet the small bit rate and high quality requirements. In contrast to that Region of Interest (ROI) coding provides an efficient compression by improving the quality of ROIs at the expense of non-ROIs. We also transmit ROI only, but reconstruct non-ROI from already transmitted content by means...
Low bit rate transmission of HD video captured from UAVs is highly interesting. Assuming a planar surface, areas contained in the current frame but not in the previous frames (New Area) can be reconstructed using Global Motion Compensation (GMC). Aiming at stereo reconstruction from monocular video by using motion parallax, a second view of each image pixel has to be additionally transmitted. Whereas...
In ear recognition problems, sparse representation based classification (SRC) has shown good performance. The dictionary used for sparse coding plays a key role in SRC. Traditional SRC methods mostly use the holistic features of the training samples to construct the dictionary for identification. But this will bring heavy computational load because of the large dimensionality of the dictionary. Therefore,...
We propose a new approach to signal reconstruction for the time encoding machine introduced by Lazar and Tóth. While practical algorithms of reconstruction from non-uniform samples are mostly based on an ill-posed block treatment of bandlimited signals, we provide a methodology to perform this reconstruction by time-varying FIR filters. Results of SNR versus complexity are given.
We propose a new inverse halftonning algorithm based on sparse coding approach, which is able to simultaneously reconstruct the continuous-tone image from the halftonned one and increase spatial image resolution. To achieve this goal, we introduce the halftonning operator that maps the continuous-tone signal into the same representation as the halftonned one. Resolution enhancement is obtained with...
The coding performance of the normative encoder of the JPEG XT in profile is analyzed and the problem on the encoder is summarized in this paper. It is pointed out that there is a mismatch in the handling of the quantization error between the normative encoder and the standard decoder. To avoid this problem, an improved structure has been proposed with consideration of the mismatch. The experimental...
The image down-conversion may be used in the block-based image compression because it can help save lots of bit-counts for each individual block. A straightforward way to implement the transform domain down-conversion is to truncate some high-frequency components to get a down-sized coefficient block. However, directly using this down-sized coefficient block to reconstruct a completed image block...
Electromagnetic radiation of PC contains video information, and the image can be reconstructed. It is well known after the Van Eck's paper. The video cable used to connect the display with the graphics controller turned out to be the primary source of the leaking signal. For digital video interface, not all kinds of color images can be intercepted and reconstructed. Firstly we analyzed which color...
The LOCO-I / JPEG-LS algorithm aims at providing lossless compression ratios but with a much lower algorithm complexity. Official designation of JPEG-LS is ISO-14495-1/ITU-T.87. JPEG-LS is a simple and efficient algorithm that mainly consists of two stages modeling and encoding. Thus it divides the whole compression process in two phases of spatial pixel prediction and entropy coding and uses contexts...
Visual feature descriptors have been successfully deployed in a wide range of applications, e.g. visual retrieval and analysis. To transmit these descriptors over bandwidth-limited networks, a high effciency feature coding technique is highly desired to maximize compression capability and achieve compact feature representations. In this paper, a hybrid visual feature descriptor compression framework...
Compressive Sensing is the present sampling paradigm which acquires only useful data, and hence reduces the acquisition time, eliminates the necessity of fast analog to digital converters and data compression stage, prior to transmission. Challenge lies in recovering the data from these few samples, which are far below Nyquist rate. Compressive sensing accomplishes this, provided the signal is sparse...
Sparse coding models have been widely used to decompose monocular images into linear combinations of small numbers of basis vectors drawn from an overcomplete set. However, little work has examined sparse coding in the context of stereopsis. In this paper, we demonstrate that sparse coding facilitates better depth inference with sparse activations than comparable feed-forward networks of the same...
Computer vision is one of the most important branches in modern industrial technology. Image classification plays an important role in computer vision since it utilizes the most advance technique in this area. However, most image classification methods only use the SIFT feature for further processing, which hinders the rich useful low-level image attributes to be captured. This paper proposes a maximal...
Intra coding is an indispensable part of all video coding systems. However, the intra prediction in the HEVC standard has several limitations with respect to the available amount of information which is exploited for the prediction and the limited number of prediction directions per block. In this paper, we propose a novel contour-based multidirectional intra coding mode which combines computer vision...
Allocating low bit-budgets to intra-coded pictures can often lead to high quantisation and loss of important high frequency information. Coding at lower resolutions can alleviate some of this distortion when utilising effective resampling techniques and filters that minimise the additional distortion introduced as a result of spatial resampling. However, it is not always possible to reconstruct each...
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