Browsing by Author "Wu, Pei-Jung"

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2D/3D-Display Auto-Adjustment Switch System
(2018-05-01)
Lin, Bor-Shyh
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Wu, Pei-Jung
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Chen, Chien-Yu
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影像與生醫光電研究所
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Institute of Imaging and Biomedical Photonics
Recently, 2-D/3-D switchable displays have become the mainstream in 3-D display technologies, and people can now watch 3-D movies with a naked 2-D/3-D switchable display at home. However, some studies have indicated that people might encounter visual fatigue after enjoying a 3-D film in the theater. Although 2-D/3-D switchable technologies have been widely developed, 3-D display technologies are still lacking in ergonomic and human-care factors such as reducing visual fatigue. This study proposes a novel 2-D/3-D display autoadjustment switch system to provide biofeedback functions to reduce users' visual fatigue. In addition, the relationship between the blink rate and the visual fatigue state while watching 3-D films was investigated and quantified. In this study, liquid crystal barrier technology was used to develop a 2-D/3-D switchable display, and a wearable EOG acquisition device was also designed to monitor electro-oculography signals to estimate the blink rate. Here, the 2-D/3-D display autoadjustment criterion of the proposed system was designed according to the change in the visual fatigue state as estimated from the blink rate. Finally, the experimental results show that the proposed system could effectively reduce users' visual fatigue while watching 3-D films.
A Creative 3D Game Platform Interacted with Laser Beam
(2013)
Chang, Sheng-Hsiung
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Chen, Chien-Yue
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Lin, Bor-Shyh
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Wu, Pei-Jung
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光電工程學系
In this study, a 3D display and interactive laser technology are integrated to develop an interface system with virtual touch and to build up a laser interactive 3D game platform.
A hybrid temporal and spatial speckle-suppression method for laser displays
(2013-12-16)
Deng, Qing-Long
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Lin, Bor-Shyh
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Wu, Pei-Jung
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Chiu, Kuan-Yao
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Fan, Ping-Lin
We propose a system that reduces laser display speckles by vibrating the light pipe. A small displacement of the light pipe appears to allow the total reflection of the laser, thereby resulting in a homogenized speckle field that changes with time. In this case, the speckle interference generated by the pattern projected by the laser through the light pipe destroys the spatial homogenization of the laser beams when the light pipe is vibrated. Moreover, when the light pipe begins the sequential vibration, the phases and paths of the beams are changed after the beams traverse the light pipe. Consequently, temporal speckle wavefront superposition can homogenize the luminous intensity distribution of the speckle pattern. This process reduces the speckle contrast to less than 4% while maintaining a luminous intensity of greater than 70%. (C) 2013 Optical Society of America
A new method of adjustment of inlet boundary for improving heat transfer of mixed convection in a vertical channel
(2016-10)
Fu, Wu-Shung
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Chao, Wei-Siang
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Wu, Pei-Jung
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Lin, Yu-Ming
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機械工程學系
This article is dedicated to a new method for improving heat transfer of mixed convection in a vertical channel from the numerical perspective. An adjustable inlet boundary is proposed in the new method to substitute an inlet that is completely occupied by the amount of fluid provided by forced convection included in mixed convection. According to this new method, the flow reversal occurring in the large Richardson number situation can be eliminated significantly, which results in an improvement in the heat transfer rate of mixed convection. In order to investigate a compressible flow problem, this study focuses on four methods, i.e., Roe scheme, preconditioning, dual time stepping, and the LUSGS (Lower Upper Symmetric-Gauss Seidel), to solve the governing equations. Except for the aperture occupied by the mount of fluid provided by forced convection, this study simulates the non-reflecting boundary conditions in other open boundaries. Based on our previous study which has successfully explored a phenomenon of flow reversal, this study intends to enhance the heat transfer rate under this circumstance, and the result has shown a significant improvement, by 29 percentage, comparing with the previous study. Also, a criterion of estimation of the necessity of forced convection included in mixed convection is proposed for enhancing heat transfer rate. Present results and existing results have good agreement. (C) 2016 Elsevier Ltd. All rights reserved.
An Augmented Reality Head-Up Display System with a Wide-View Eyebox
(2020-06-30)
Wu, Pei-Jung
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Chuang, Chih-Hao
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Chen, Chien-Yu
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Wu, Jeng-Han
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Lin, Bor-Shyh
This study proposes to apply the combination of two 90-degree prisms and a holographic optical element to an image-dividing element, divide an image into three through the virtual image projection system, and accurately project the images to 160 cm behind the windshield. In order to distinguish the left image, middle image, and right image at the horizontal direction, the 90-degree prism is first utilized for horizontally deflecting the light, a holographic optical element is then used for presenting the vertical deflection of the image, and finally, the images are horizontally arranged as a real image on the diffuser. An image-dividing element is eventually integrated to the virtual image projection system. Then, the divided images are made as a virtual image which is projected to 160 cm behind the windshield to combine with the street scene. The horizontal angle of view of an eyebox is increased from 2.51 degrees to 7.22 degrees, and the size of the eyebox is 31.68 cm x 12.48 cm, allowing a wide-view laser-based head-up display with the large-angle beam-splitting function being successfully designed. It would not affect the field of view on the road, and this system could reduce the space and be arranged easily in a vehicle. Therefore, this proposed system is suitable for the aftermarket.
Design of Smart Brain Oxygenation Monitoring System for Estimating Cardiovascular Disease Severity
(2020-01-01)
Chou, Willy
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Wu, Pei-Jung
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Fang, Chih-Chieh
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Yen, Yun-Shan
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Lin, Bor-Shyh
Clinically, cardiovascular disease (CVD) patients need physicians to suggest different exercise training and rehabilitation procedures to improve their cardiopulmonary function (CPF). In previous studies, several approaches, such as cardiopulmonary exercise testing (CPET), echocardiography and computed tomography angiography (CTA), were proposed to indirectly estimate the rehabilitation effect on CPF. However, the above approached require experienced operators and complex equipment. In this study, a smart and wearable brain oxygenation monitoring system without motion artifact and crosstalk is proposed to estimate the blood circulation state of brain tissue directly during incremental exercise. Moreover, the technique of neural network is also used for classifying different CPF groups from the indexes extracted from the measured hemoglobin parameters. The experimental results show that the defined indexes extracted from the hemoglobin parameters can present the state of CPF, and the proposed smart brain oxygenation monitoring system can also effectively and automatically classify different CPF groups from these indexes via artificial intelligence. The proposed system therefore may assist physicians in the clinical evaluation of the CVD severity and rehabilitation effect on CPF in the future.
Design of Wearable Brain Computer Interface Based on Motor Imagery
(2014-01-01)
Lin, Chuan-Lung
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Chu, Tso-Yao
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Wu, Pei-Jung
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Wang, Chen-An
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Lin, Bor-Shyh
Brain computer interface (BCI) is a communication system to establish a communication interface between the brain and the device. Motor imagery-based brain computer interface is one of asynchronous BCIs, and have been widely developed in recent years. However, most of motor imagery-based BCI require bulk EEG machines, and lots of EEG data have to be transmitted to the back-end computer for analysis. This also causes the limitation of daily applications. In this study, a wearable motor-imagery-based BCI system with the least number of EEG channels was developed. In this system, the wearable mechanical design and the wireless EEG acquisition module were designed for measuring real time EEG in daily life. The modified BCI algorithm was also developed, and here only three channels are used to distinguish different events of motor imagery in this study. Finally, the proposed BCI system was also validated by the hand-motor imagery experiment.
Development of a Smart Assistance System for Patients With Blepharoptosis
(2019-01-01)
Lien, Ching-Feng
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Wu, Pei-Jung
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Liao, Lu-Xun
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Jeng, Seng-Feng
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Chang, Li-Ren
Blepharoptosis is defined as an abnormal low-lying upper eyelid margin in primary gaze. Without adequate management, the disease may cause amblyopia, strabismus, and astigmatism in children as well as constriction of the upper visual field, blurred vision, increased tearing, fatigue, and frontal headache in adults. In most cases of blepharoptosis, surgical intervention is the primary treatment. However, the risk of recurrence is high, and some complications may occur after the surgical intervention. Although ptosis crutches and magnetic eyelid devices have been reported to be beneficial for managing the disease, many disadvantages must be overcome. To avoid sequelae from the disease and to mitigate the discomfort and complications, this study proposes a novel assistance system. In this system, a controllable permanent electromagnet and a piece of iron sheet affixed to the paralytic upper eyelid were used for elevating the drooping eyelid according to the degree of the eyelid being opened or closed, as estimated by an optical probe. Finally, the performance of the proposed system in detecting eyelid actions and the effect of eyelid elevation were validated. The experimental results showed that the proposed system could effectively detect eyelid closing events and successfully, symmetrically, and synchronously elevate the drooping upper eyelid with a mean correction of 3.5 +/- 0.4 mm (range, 2.7 - 4.0 mm) in 14 patients with unilateral blepharoptosis. The proposed system therefore may be applied to patients with unilateral blepharoptosis in the future.
Integral computer-generated hologram via a modified Gerchberg-Saxton algorithm
(2015-01-01)
Wu, Pei-Jung
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Chen, Chien-Yue
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Deng, Qing-Long
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Chang, Hsuan T.
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Lin, Bor-Shyh
An integral computer-generated hologram, which modulates the phase function of an object based on a modified Gerchberg-Saxton algorithm and compiles a digital cryptographic diagram with phase synthesis, is proposed in this study. When the diagram completes position demultiplexing decipherment, multi-angle elemental images can be reconstructed. Furthermore, an integral CGH with a depth of 225 mm and a visual angle of +/- 11 degrees is projected through the lens array.
Near-infrared Spectroscopy System for Determining Brain Hemoglobin Level
(2013)
Wu, Pei-Jung
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Chang, Ming-Hsien
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Huang, Cheng-Yang
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Wang, Yu-Cheng
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Kuo, Jinn-Rung
Traumatic brain injury (TBI) usually results from brain shaking or impact. It can affect the normal function of the brain and even cause people become disabled and death. However, there is lack of studies for the physiological changes of humans or animals under brain injury. In order to obtain the information of physiological state change, we designed and enforced a non-invasive, wireless multi-channel near-infrared spectroscopy (NIRS) for monitoring the concentration change of oxy-hemoglobin (HbO(2)), deoxy-hemoglobin (HbR) and total-hemoglobin (HbT) continuously during and after TBI. The experimental results indicated that the concentration change of HbO(2) and HbT is significantly related to the impact strength and infarction volume. Thus, this system is easily used and stable for TBI study.
Speckle reduction by combination of digital filter and optical suppression in a modified Gerchberg-Saxton algorithm computer-generated hologram
(2014-09-20)
Chen, Chien-Yue
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Deng, Qing-Long
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Wu, Pei-Jung
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Lin, Bor-Shyh
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Chang, Hsuan T.
A speckleless illuminated modified-Gerchberg-Saxton-algorithm-type computer-generated hologram, which adopts a lower frequency of the iterative algorithm and calculation time, is proposed to code a hologram with two signals and position a multiplexing phase-only function, which can reconstruct the left and the right viewing holograms on the pupillary-distance position after the decryption and still maintain the content with high contrast and definition. The reconstructed image quality presents root mean square error of 0.03, with a diffraction efficiency of 87%, and signal-to-noise ratio of 8 dB after the analysis. Furthermore, two denoising techniques for the digital filter and optical suppression are combined, in which the speckle suppression with pseudorandom phase modulation and a rotating diffuser are utilized for successfully reducing the speckle contrast, which was reduced to below 4%. The goal was to reduce visual fatigue for the viewers. (C) 2014 Optical Society of America
The comparison of accommodative response and ocular movements in viewing 3D and 2D displays
(2017-09-01)
Cho, Ta-Hsiung
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Chen, Chien-Yu
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Wu, Pei-Jung
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Chen, Kun-Shiang
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Yin, Li-Te
Some people often appear asthenopia symptoms of eye fatigue, double vision, nausea, and dizziness while viewing 3D movies. By testing the changes of accommodation function and ocular movements during watching 3D and 2D movies, the factors in visual discomfort are confirmed in this study. 20 subjects with normal visual acuity and binocular vision function view 3D and 2D movies with the same content for 30 min, and the amplitude of accommodation, binocular vergence ability, stereo-acuity, and tear break-up time of the subjects before and after viewing the films are measured. Furthermore, an open-field auto-refractor is utilized for synchronously testing the change of accommodative response while viewing 3D and 2D films, and Skalar IRIS tracking system is applied to record ocular movements through infrared positioning. In comparison with viewing 2D movies, the accommodative response and ocular movements reveal obvious changes while viewing 3D movies. The accommodation ability and binocular vergence ability obviously drop after viewing 3D movies; moreover, the stability of stereo-acuity and tear film also gets worse. The changes of such physiological factors might be the major cause of asthenopia. (C) 2017 Elsevier B.V. All rights reserved.
The influence of polarized 3D display on autonomic nervous activities
(2014-10-01)
Chen, Chien-Yue
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Ke, Ming-Da
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Wu, Pei-Jung
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Kuo, Chen-Deng
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Pong, Bao-Jen
The spectral analysis of Heart Rate Variability (HRV) can be used for assessing the autonomic nervous activities and further the physiological conditions of subjects. This study intended to explore whether or not people would have fatigue, faintness and other kinds of uncomfortable conditions after watching a 3D film by using HRV measures as the objective physiological indices, in addition to other subjective physiological indices. Twenty men aged 22 +/- 2 experienced watching 3D films and 2D films and were served as the controls of themselves. As the controls, the subjects had to rest at the same place. All subjects were are randomized for taking different experiences, and the electrocardiographic (ECG) signals were recorded during the whole process. The researchers could obtain the indices of the autonomic nervous activities before and after experiencing 3D and 2D movies with the help of spectral HRV analyses, along with the objective physiological information. The subjects were requested to fill out the questionnaire for the subjective feelings after the movie experiences. It was found that the subjects\' high-frequency power (HFP) representing parasympathetic nervous activities decreases after watching a 3D film. The sympathetic and parasympathetic nerve activities before and after watching a 2D film were not significantly different. The subjects complained that they felt dizzy, had headaches, and got visual fatigue while watching a 3D film. This study found that the subjects\' parasympathetic nerve activities were reduced after watching a 3D film, indicating that watching a 3D film would make people uncomfortable and tired. This result was the same as that of the questionnaire. Thus, HRV analyses could be an objective physiological index for discomfort as viewing 3D films. (C) 2014 Elsevier B.V. All rights reserved.
The Investigation on Physiological Influences and the Working Efficiencies of Several Lighting in Market
(2013)
Chen, Chien-Yue
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Ke, Ming-Da
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Wu, Jeng-Han
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Wu, Pei-Jung
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光電工程學系
Human physiological and psychological changes could be acquired by biofeedback instruments and self-report questionnaire. People are likely to generate various physiological and psychological changes when situating distinct lighting. For this reason, this study aims to discuss the effects of environments with different light sources, such as reading, practical training, working, and sleeping, on human heart rate variability. It is expected to inspect the effects of commercial light sources on human body through the measurement and experiment and further find out the suitable light sources in various environments.
Wireless Monitoring System for Oral-feeding Evaluation of Preterm Infants
(2014-01-01)
Wang, Chen-An
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Liao, Yi-Chien
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Wu, Pei-Jung
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Wang, Yu-Lin
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Lin, Bor-Shing
Feeding and swallowing disorders are relatively common in early infancy. In Clinical, it shows negative impacts on growth and neurodevelopmental, therefore it has become a high risk of neurodevelopmental delays in preterm infants. Oral feeding that requires suckling, swallowing, and breathing coordination, and it is the most complex sensorimotor process for the newborn infant. Currently, both preterm infant\'s oral feeding disorders and severity are dependent on subjective clinical experience. Directly monitoring sucking-swallowing-breathing activities of oral is difficult for preterm infants. In this study, a wireless monitoring system for oral feeding of preterm infants was developed to monitor the events of sucking-swallowing-breathing activities continuously and objectively. Finally, the experimental results show that the proposed system can detect the events of sucking, swallowing, and breathing activities effectively.