Browsing by Author "Lin, Yen-Chen"

Now showing 1 - 6 of 6

Deep 360 Pilot: Learning a Deep Agent for Piloting through 360 degrees Sports Videos
(2017-01-01)
Hu, Hou-Ning
;
Lin, Yen-Chen
;
Liu, Ming-Yu
;
Cheng, Hsien-Tzu
;
Chang, Yung-Ju
Watching a 360 degrees sports video requires a viewer to continuously select a viewing angle, either through a sequence of mouse clicks or head movements. To relieve the viewer from this "360 piloting" task, we propose "deep 360 pilot" - a deep learning-based agent for piloting through 360 degrees sports videos automatically. At each frame, the agent observes a panoramic image and has the knowledge of previously selected viewing angles. The task of the agent is to shift the current viewing angle (i.e. action) to the next preferred one (i.e., goal). We propose to directly learn an online policy of the agent from data. Specifically, we leverage a state-of-the-art object detector to propose a few candidate objects of interest (yellow boxes in Fig. 1). Then, a recurrent neural network is used to select the main object (green dash boxes in Fig. 1). Given the main object and previously selected viewing angles, our method regresses a shift in viewing angle to move to the next one. We use the policy gradient technique to jointly train our pipeline, by minimizing: (1) a regression loss measuring the distance between the selected and ground truth viewing angles, (2) a smoothness loss encouraging smooth transition in viewing angle, and (3) maximizing an expected reward of focusing on a foreground object. To evaluate our method, we built a new 360-Sports video dataset consisting of five sports domains. We trained domain-specific agents and achieved the best performance on viewing angle selection accuracy and users' preference compared to [53] and other baselines.
Integrated digital and analog microfluidics by EWOD and LDEP
(2006)
Lin, Yen-Chen
;
Chuang, Kai-Cheng
;
Wang, Tsu-Te
;
Chiu, Cheng-Pu
;
Fan, Shih-Kang
EWOD (electrowetting-on-dielectric) and LDEP (liquid dielectrophoresis) are investigated to provide digital and analog microfluidic functions on an integrated chip respectively. By altering the frequency of the applied voltage and the surrounding medium of a EWOD device, we found that when using off as surrounding medium and applying an AC signal similar to 100 kHz, liquid column would be drawn and follow the thin connecting lines of the EWOD driving electrodes instead of remaining on top of the center of the EWOD driving electrodes. This new phenomenon is described in this paper and is regarded as a LDEP effect. Three fundamental tools for integrated digital and analog microfluidics are developed, including a digital-to-analog converter, an analog-to-digital converter, and a valve. Combining EWOD and LDEP effects, liquids can be pumped on a virtual channel (analog microfluidics), defined by energized thin LDEP electrode lines, continuously from liquid reservoir or from a digitized droplet (digital microfluidics). On the contrary, liquids on LDEP electrodes (analog microfluldics) can also be pumped on a EWOD electrode and be digitized in droplet forms with precise volumes (digital microfluidics). EWOD and LDEP can be selectively programmed on a single chip, making integrated digital and analog microfluidics a reality.
Polarization ratio enhancement of a-plane GaN light emitting diodes by asymmetric two-dimensional photonic crystals
(2014-05-21)
Chou, Yen
;
Li, Hsiang-Wei
;
Yin, Yu-Feng
;
Wang, Yu-Ting
;
Lin, Yen-Chen
Fabricating photonic crystals (PhCs) on GaN based non-polar light emitting diodes (LEDs) is an effective way to increase light extraction and meanwhile to preserve or improve polarization ratio. In this work, a-plane GaN LEDs with two-dimensional PhCs were demonstrated. With the E // m polarized modes (which mean the optical polarization with the electric field parallel to m-axis) as the target of diffraction, we matched E//m modes to the photonic bands and aligned E//c modes to fall within the photonic band gap. The results show stronger E//m but weaker E//c mode diffractions on both c- and m-axes. At the vertical direction, the polarization ratio is enhanced from 45.8% for the planar device to 52.3% for the LEDs with PhCs. (C) 2014 AIP Publishing LLC.
Radiative recombination of indirect exciton in type-II ZnSeTe/ZnSe multiple quantum wells
(2011-05-01)
Chia, Chin-Hau
;
Fan, Wen-Chung
;
Lin, Yen-Chen
;
Chou, Wu-Ching
;
電子物理學系
The tunability of the emission energy, oscillator strength and photoluminescence (PL) efficiency by varying the well thickness and excitation density was demonstrated in the ZnSe(0.8)Te(0.2)/ZnSe multiple quantum wells. A significant blueshift about 260 meV of the PL peak energy was observed as the well width decreased from 5 to 1 nm. An extraordinary long lifetime (300 ns) of the recombination for the widest sample was detected. The binding energy of the indirect excitons is determined as 12 meV for the thinnest sample. The reduction of PL efficiency by thermal energy is greatly suppressed by employing a high excitation power. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.
Reconfigurable liquid pumping in electric-field-defined virtual microchannels by dielectrophoresis
(2009)
Fan, Shih-Kang
;
Chen, Wen-Jung
;
Lin, Tin-Hsu
;
Wang, Tsu-Te
;
Lin, Yen-Chen
Dielectrophoresis (DEP), widely used to generate body forces on suspended particles, is investigated to provide surface forces at the liquid-medium interfaces and pump a high-permittivity liquid in a low-permittivity medium along a virtual microchannel defined by an electric field between parallel plates. Because the pumping pressure is proportional to the square of the intensity of the electric field and independent of the channel width, DEP pumping is advantageous as the dimension of the microchannel shrinks down. The absence of the channel walls simplifies the fabrication processes and further increases its feasibility in nanofluidic applications. We demonstrate water pumping in an immiscible silicone oil medium at adjustable velocities by applying voltages above the threshold value whose square is linearly proportional to the cross-sectional aspect ratio (AR), i.e., the height to width ratio, of the microchannel. With a properly designed AR, liquid valve is achieved by appropriate voltage applications. Without the barriers of channel walls, merging multiple streams and capillary filling of the spacing between electric-field-defined virtual microchannels are observed and studied. Moreover, in situ reconfigurable liquid pumping is demonstrated by a four way switching valve on a programmable crossing electrode set.
Tell Me Where to Look: Investigating Ways for Assisting Focus in 360 degrees Video
(2017-01-01)
Lin, Yen-Chen
;
Chang, Yung-Ju
;
Hu, Hou-Ning
;
Cheng, Hsien-Tzu
;
Huang, Chi-Wen
360 degrees videos give viewers a spherical view and immersive experience of surroundings. However, one challenge of watching 360 degrees videos is continuously focusing and refocusing intended targets. To address this challenge, we developed two Focus Assistance techniques: Auto Pilot (directly bringing viewers to the target), and Visual Guidance (indicating the direction of the target). We conducted an experiment to measure viewers' video-watching experience and discomfort using these techniques and obtained their qualitative feedback. We showed that: 1) Focus Assistance improved ease of focus. 2) Focus Assistance techniques have specificity to video content. 3) Participants' preference of and experience with Focus Assistance depended not only on individual difference but also on their goal of watching the video. 4) Factors such as view-moving-distance, salience of the intended target and guidance, and language comprehension affected participants' video-watching experience. Based on these findings, we provide design implications for better 360 degrees video focus assistance.