One of the available capacities of satellite application is applying in Earth Observation (EO) video capture satellites. On the one hand, the governing equations of satellite motion in orbit indicate the fact that a satellite moves in a very predictable manner and stays on schedule. On the other hand, the superiority of Intra and Inter codings, drive video compressors to reduce the spatial redundancy and data rate. This advantage stems from the flexible coding structure and high density of angular prediction modes, in all video compression versions. How to combine these facts to achieve better performance in industrial satellite applications is our aim in this article. In this study, a novel architectural approach for EO video capture satellites that have taken the new demands of the next commercial market has been proposed. Here after looking at video coding parameters, technical EO satellite essentialities, and proving the proposed hypothesis by simulation and evidence, a preliminary configuration has been described. The Attitude and orbit control systems (AOCS) are responsible for keeping the satellite position in the required condition contributing to Onboard Data Handling (OBDH). The exact parameters of direction are key factors that can be used besides video prediction vector data to reduce calculation load in video compression algorithms that particularly explained.
In this paper, a method to eliminate the interference of the-structured light cameras is presented. 3D reconstruction is a key procedure of 3D technologies. The depth information is significant for 3D reconstruction of a certain scene and the depth camera based on structured light is widely used. This kind of cameras can get the depth information of a certain scene by emitting a beam of structured light and capture it after reflection. In order to enlarge the range of 3D reconstruction, more than one depth-cameras are used simultaneously in one scene. However, when working together, the lights emitted by those cameras would overlap in the scene. The light pattern captured by the cameras would be interfered by others and the depth they calculated would be wrong correspondingly. The method presented in this paper abstracts the progress of modulation and demodulation to a modulation matrix. Based on that, this paper provides a procedure of the whole process of interference elimination. We also optimize the matrix based on the thought of interfere alignment. Finally, the result of simulation was presented and verify the efficiency of the method.
With the rapid development of wireless video communication and remote monitoring, the encoder is required to be
low-complexity and low-power. Distributed video coding effectively reduces the complexity of encoder, since it
shifts a majority of computation to the decoder. Frame interpolation is a key component of typical DVC system. It
reconstructs the WZ frame based on the intra coded key frame, namely side information generation. The fewer
differences between the side information and original WZ frame corresponds to the lower translating bit rate. In this
paper, we carry out a new motion compensated interpolation based on non-uniform motion trajectory to refine the
side information. Multiple reference frames is applied to fulfill our proposal. Testing results show that the proposed
scheme improves the PSNR by 0.3-0.5dB in comparison with hierarchical block matching algorithm, and upgrades
the rate-distortion performance in a certain degree.
Distributed video coding (DVC) is a new video coding paradigm that shifts the complexity from the encoder side to the decoder side. One particular case of DVC, the Wyner-Ziv coding scheme, encodes each video frame separately and decodes the video sequence jointly with side information. This paper presents a new Wyner-Ziv video coding scheme based on hierarchical block matching algorithm (HBMA). In this proposed scheme, the side information is greatly refined to assist the reconstruction of the Wyner-Ziv frames. The bidirectional motion estimation and the forward motion estimation are associated to generate the interpolated frame from temporally adjacent key frames to attain the high fidelity side information. During the bidirectional motion estimation, the size of the block and the search area vary at different levels of hierarchy. In additional, the motion vectors are inherited from big blocks to small blocks by choosing the smallest mean-of-the-absolute-difference value among neighboring blocks. Preliminary experiment results show that the proposed scheme can achieve better rate-distortion performance by 0.5-1 dB compared to the existing Wyner-Ziv video coding with the slightly increased decoding complexity.
SPIHT is one of the most efficient image compression algorithms. It had been successfully applied to a wide variety of
images, such as medical and remote sensing images. However, it is highly susceptible to channel errors. A single bit
error could potentially lead to decoder derailment. In this paper, we integrate new error resilient tools into wavelet
coding algorithm and present an error-resilient image transmission scheme based on virtual set partitioning in
hierarchical trees (SPIHT), EREC and self truncation mechanism. After wavelet decomposition, the virtual spatial-orientation
trees in the wavelet domain are individually encoded using virtual SPIHT. Since the self-similarity across sub
bands is preserved, a high source coding efficiency can be achieved. The scheme is essentially a tree-based coding, thus
error propagation is limited within each virtual tree. The number of virtual trees may be adjusted according to the
channel conditions. When the channel is excellent, we may decrease the number of trees to further improve the
compression efficiency, otherwise increase the number of trees to guarantee the error resilience to channel. EREC is also
adopted to enhance the error resilience capability of the compressed bit streams. At the receiving side, the self-truncation
mechanism based on self constraint of set partition trees is introduced. The decoding of any sub-tree halts in case the
violation of self-constraint relationship occurs in the tree. So the bits impacted by the error propagation are limited and
more likely located in the low bit-layers. In additional, inter-trees interpolation method is applied, thus some errors are
compensated. Preliminary experimental results demonstrate that the proposed scheme can achieve much more benefits
on error resilience.
KEYWORDS: Computer programming, Video coding, Video, Error control coding, Data compression, Video compression, Motion estimation, Video surveillance, Error analysis, Forward error correction
In this paper, we present a distributed video coding scheme based on zero motion identification at the decoder and constrained rate adaptive low density parity check (LDPC) codes. Zero-motion-block identification mechanism is introduced at the decoder, which takes the characters of video sequence into account. The constrained error control decoder can use the bits in the zero motion blocks as a constraint to achieve a better decoding performance and further improve the overall video compression efficiency. It is only at the decoder side that the proposed scheme exploits temporal and spatial redundancy without introducing any additional processing at the encoder side, which keeps the complexity of the encoding as low as possible with certain compression efficiency. As a powerful alternative to Turbo codes, LDPC codes have been applied to our scheme. Since video data are highly non-ergodic, we use rate-adaptive LDPC codes to fit this variation of the achievable compression rate in our scheme. We propose a constrained LDPC decoder not only to improve the decoder efficiency but also to speed the convergence of the iterative decoding. Simulation demonstrates that the scheme has significant improvement in the performances. In addition, the proposed constrained LDPC decoder may benefit other application.
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