Browsing by Author "Kuo, Lun-Chia"

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A Walking Velocity Update Technique for Pedestrian Dead-Reckoning Applications
(2011)
Lo, Chi-Chung
;
Chiu, Chen-Pin
;
Tseng, Yu-Chee
;
Chang, Sheng-An
;
Kuo, Lun-Chia
Inertial sensors for pedestrian dead-reckoning (PDR) have been attracting considerable attention recently. Since accelerometers are prone to the accumulation of errors, a "Zero Velocity Update" (Z-UPT) technique [1], [2] was proposed as a means to calibrate the velocity of pedestrians. However, these inertial sensors must be mounted on the bottom of the foot, resulting in excessive vibration and errors when measuring speed or orientation. This paper proposes a self-calibrating PDR solution using two inertial sensors in conjunction with a novel concept called "Walking Velocity Update" (W-UPT). One inertial sensor is mounted on the lower leg to identify a point suitable for calibrating the walking velocity of the user (when its pitch value becomes zero), while another sensor is mounted on the upper body to track the velocity and orientation. We have developed a working prototype and tested the proposed system using actual data.
MULTIDIMENSIONAL SVC BITSTREAM ADAPTATION AND EXTRACTION FOR RATE-DISTORTION OPTIMIZED HETEROGENEOUS MULTICASTING AND PLAYBACK
(2008)
Peng, Wen-Hsiao
;
Zao, John K.
;
Huang, Hsueh-Ting
;
Wang, Tse-Wei
;
Kuo, Lun-Chia
In this paper, we propose an optimal SVC bitstream extraction scheme that can produce scalable layer representations for different viewing devices scattered over a multicasting network with diverse link bandwidth. Our scheme can determine optimal extraction orders/paths that are implementable at different multicasting nodes by performing successive steps of multiple adaptation. In addition to this basic scheme, we also develop an unambiguous denotation for the optimal extraction paths, and an algorithm for deducing the optimal extraction paths for less capable devices through path truncation. Extensive SVC encoding and adaptation experiments have been performed using JSVM 9 and both objective quality metrics (PSNR and MSE) as well as subjective metric (VQM). The experiment results showed that our scheme works well if convexity of R-D performance is maintained throughout the SVC bitstream.
Rate-distortion optimized SVC bitstream extraction for heterogeneous devices : A preliminary investigation
(2007)
Peng, Wen-Hsiao
;
Huang, Lin-Shung
;
Zao, John K.
;
Lu, Jiun-Shien
;
Wang, Tse-Wei
The emerging SVC standard enables partial extraction and decoding of video bitstreams, and thus allows various viewing devices to adapt their video reception and playback according to devices capability and network performance. This desirable feature, however, comes with a caveat: the parts of a bitstream needed for providing good quality playback at different devices may differ significantly depending on the visual characteristics of video programs, the quantization and dependency settings of SVC encoders as well as the display formats of viewing devices. In this paper, we present the results of our preliminary investigation on the intricate relations among these factors. We discovered a set of constraints on the setting of quantization parameters and the choices of reference layers for inter-layer dependencies that ensures good rate-distortion trade-offs and regular bitstream; extraction paths. We called these constraints, the adaptation rules for inter-layer encoding, and their resulting outputs, the well-adapted layers/bitstreams. We further discovered that bitstream extraction by different viewing devices follow predictable paths if the SVC bitstream is well-adapted and the playback process extracts a complete set of interdependent network abstraction layer (NAL) units in every refinement step. These regular extraction paths enabled us to develop an efficient bitstream extraction algorithm based on local optimization of rate-distortion ratios. The experimental results using standard testing sequences confirmed our findings.