Upsampling

About: Upsampling is a research topic. Over the lifetime, 2426 publications have been published within this topic receiving 57613 citations.

Adaptive inter-layer intra prediction in scalable video coding

Abstract: In the scalable video coding (SVC) standard, interlayer intra prediction (ILIP) is one of the most fundamental coding tools used to reduce bit rate. The prediction block of macroblock (MB) in enhancement layer (EL) is obtained by upsampling the co-located base layer (BL) block. In this paper, we propose a new ILIP method by introducing the adaptive signal processing techniques. Adaptive Wiener filters, which are calculated for each frame independently, are used to generate a prediction signal with minimum error energy. On average, a coding gain of 3.6% reduction of bit rate is obtained for QCIF-CIF scenario. Up to 9% bit rate reduction is achieved for CIF-4CIF scenario.

Quaternionic Upsampling: Hyperspherical Techniques for 6 DoF Pose Tracking

Abstract: Fast real-time tracking is an integral component of modern 3D computer vision pipelines. Despite their advantages in accuracy and reliability, optical trackers suffer from limited acquisition rates depending either on intrinsic sensor capabilities or physical limitations such as exposure time. Moreover, data transmission and image processing produce latency in the pose stream. We introduce quaternionic upsampling to overcome these problems. The technique models the pose parameters as points on multidimensional hyperspheres in (dual) quaternion space. In order to upsample the pose stream, we present several methods to sample points on geodesics and piecewise continuous curves on these manifolds and compare them regarding accuracy and computation efficiency. With the unified approach of quaternionic upsampling, both interpolation and extrapolation in pose space can be done by continuous linear variation of only one sampling parameter. Since the method can be implemented rather efficiently, pose rates of over 4 kHz and future pose predictions with an accuracy of 128 µm and 0.5° are possible in real-time. The method does not depend on a special tracking algorithm and can thus be used for any arbitrary 3 DoF or 6 DoF rotation or pose tracking system.

A stereoscopic video conversion scheme based on spatio-temporal analysis of MPEG videos

Abstract: In this article, an automatic stereoscopic video conversion scheme which accepts MPEG-encoded videos as input is proposed. Our scheme is depth-based, relying on spatio-temporal analysis of the decoded video data to yield depth perception cues, such as temporal motion and spatial contrast, which reflect the relative depths between the foreground and the background areas. Our scheme is shot-adaptive, demanding that shot change detection and shot classification be performed for tuning of algorithm or parameters that are used for depth cue combination. The above-mentioned depth estimation is initially block-based, followed by a locally adaptive joint trilateral upsampling algorithm to reduce the computing load significantly. A recursive temporal filter is used to reduce the possible depth fluctuations (and also artifacts in the synthesized images) resulting from wrong depth estimations. The traditional Depth-Image-Based-Rendering algorithm is used to synthesize the left- and right-view frames for 3D display. Subjective tests show that videos converted by our scheme provide comparable perceived depth and visual quality with those converted from the depth data calculated by stereo vision techniques. Also, our scheme is shown to outperform the well-known TriDef software in terms of human’s perceived 3D depth. Based on the implementation by using “OpenMP” parallel programming model, our scheme is capable of executing in real-time on a multi-core CPU platform.

Data-assisted satellite-borne AIS (automatic identification system) signal synchronization parameter estimation method and system

Abstract: A data-assisted satellite-borne AIS signal synchronization parameter estimation method comprises that an antenna receives a radio frequency signal emitted by an earth ship AIS system and sends the radio frequency signal to a receiver; the receiver demodulates the received radio frequency signal into a baseband signal and inputs the demodulated radio frequency signal into an FPGA (field programmable gate array) data acquisition module; the FPGA data acquisition module subjects the received baseband signal to analog-digital conversion to obtain a digital baseband signal and inputs the digital baseband signal into a signal processing module; the signal processing module processes the received digital baseband signal to obtain correct AIS ship information and to send the correct AIS ship information into a data storage module; and the data storage module stores the received AIS ship information. The data-assisted satellite-borne AIS signal synchronization parameter estimation method has the advantages that under signal downsampling and by introducing the self-correlation operation and the maximum likelihood operation, the performance of large estimation range and small estimation error of frequency offset of the satellite-borne AIS signal can be achieved; and through the accumulation argument operation and the accumulation module value operation, high-accuracy timing estimation, phase shift estimation and amplitude estimation are achieved.

Multiresolution maximum intensity volume rendering by morphological pyramids

Abstract: We propose a multiresolution representation for maximum intensity projection (MIP) volume rendering, based on morphological pyramids which allow progressive refinement and have the property of perfect reconstruction. The pyramidal analysis and synthesis operators are composed of morphological erosion and dilation, combined with dyadic downsampling for analysis and dyadic upsampling for synthesis. The structure of the multiresolution MIP representation is very similar to wavelet splatting, the main differences being that (i) linear summation of voxel values is replaced by maximum computation, and (ii) linear wavelet filters are replaced by (nonlinear) morphological filters.