Jinn-Cherng Yang

System-crosstalk effect on stereopsis human factor study for 3D displays

The ghost image induced by System-Crosstalk (SCT) of 3D display, due to optical hardware imperfections, is the major factor to jeopardize stereopsis. The system crosstalk can be measured by optical measuring instrument and describes the optical leakage from the neighboring viewing zones. The amount of crosstalk reduces the ability of the viewer to fuse the stereo-images into 3D images. The Viewer-Crosstalk (VCT), combined with hardware and content issues, is an overall evaluation of the ghost image and can be easily interpreted based on the principle of binocular 3D display. The examination of different SCT values was carried out with a seven-grade subjective evaluation test. In our previous study, it was shown that many other factors, such as contrast ratio, disparity and monocular cues of the images, play important roles in the stereopsis. In this paper, we study the factors of stereo-images with different crosstalk levels that may affect stereopsis. For simulate the interference between stereo-images, digital image processing are employed to assign different levels of crosstalk to each other at properly specified disparity between images. Results of this research can provide valuable reference to the content makers and for the optimized design of 3D displays with minimum System Crosstalk.

Challenge of 3D LCD Displays

A multiview autostereoscopic LCD display with a localized 2D/3D switching function is developed based on the actively switchable parallax barrier technology. This switchable barrier comprises of an electro-optically switchable liquid crystal (LC) and a microretarder. Polymer dispersed liquid crystal (PDLC) with switchable clear and diffusing states and twisted nematic liquid crystal (TNLC) with polarization switching function are used as switching devices. The microretarder is prepared by self-developed multibeam laser scanning process, which is clean, friendly to the environment, and easy for scale up and mass production. The influence factors on the image qualities of 3D displays based on LCD panel technology are analyzed and discussed. Some solutions have proposed to solve the commercial application issues.

Low Power Consumption PZT Actuated Micro-Pump

Direct methanol fuel cells (DMFC) that convert the chemical energy of the fuels directly into electrical energy are considered to be the key technology for power generation in portable electronics like cellular phones, laptop computers and wearable electronics and have received considerable research attention in recent years. This study applies the PZT actuator as the driving source of the micro-pump, which is used to circulate fuel within a DMFC power system. It conquered the usual disadvantage of high voltage needed to drive PZT actuator. It is capable of pumping both the liquid and air gas with the unique check valve design within the micro-fluidic channel and the pump material is made of EPDM to stand with the erosion of liquid methanol as fuel of DMFC device. It also consists the character of small size for the micro-pump after packaging process. Spec of the micro-pump developed by this project is 3 c.c./min of pumping flow rate or 150 mm-H2O for pumping pressure head at the condition of plusmn24 volts and 20 Hz for driving voltage and frequency, respectively, and power consumption is only about 40 mW. Since the micro-pump driven by a PZT actuator, the power consumption and heat generation by the micro-pump are negligible. Also, with the piezoelectric actuation being instantaneous, there is no delay in generating mechanical motion of the diaphragm from a given electrical input. Moreover, the pumping speed can precisely be controlled due to a very good linearity of the pump response

Human factor study on the crosstalk of multiview autostereoscopic displays

Stereoscopic depth perception has been analyzed in many laboratory experiments since Wheatstones (1838) discovery that disparity is a sufficient and compelling stimulus for the perception of depth with mirror-type stereo displays. In this paper, mirror-type stereo displays were used as the instrument to simulate the 3D image in the human factor experiment. It can be used to simulate the 9 view 3D display by image processing method with different multi-view crosstalk levels measured from luminance measurement device. The disparity of multi-view images to form stereopsis with depth perception is decided by the 9-view autostereoscopic 3D display that subject can properly fuse the image to get the proper visual depth. Computer graphic method applied for multi-view content rendering with shooting distance of 70 cm for each virtual camera. The distance between cameras is 5.6 cm with parallel capture to simulate the images accepted by human eyes. The experimental design was used for testing subjective evaluations based on the questionnaire, and ANOVA methods were used for analysis. Experimental variables of this human factor study for multi-view 3D display are five levels of crosstalk distribution from measured data, with or without shadow effects and perspective line shown within tested images. In addition, the result of acceptable system crosstalk level for multi-view stereoscopic display is between Level 4.7 and Level 5.9 in average for the four tested images.

Evaluation of an Eye Tracking Technology for 3D Display Applications

Due to the bandwidth constraints of multi-view autostereoscopic display that severely restrict number of views simultaneously displayed without degrading resolution or increasing display cost unacceptably. The alternative way is the eye tracking technology, which can fluently rendering and accurately projecting the stereo video to the viewer. In order to render stereo content with respect to users view points and to optically project the content onto the left and right eyes of the user accurately, the real-time viewer tracking technique that allows the user to move around freely when watching the autostereoscopic display is developed in this study. It comprises the face detection by using multiple eigenspaces of various lighting conditions, fast block matching for tracking four motion parameters of the users face region. The Edge Orientation Histogram (EOH) on Real AdaBoost to improve the performance of original AdaBoost algorithm using Haar feature in OpenCV library developed by Intel is also applied in this study. Since performance of the viewer tracking autostereoscopic display is still influenced under variant environmental conditions, the robustness and efficiency of the viewer-tracking system are evaluated in this study.

Study of a viewer tracking system with multiview 3D display

An autostereoscopic display provides users great enjoyment of stereo visualization without uncomfortable and inconvenient drawbacks of wearing stereo glasses. However, bandwidth constraints of current multi-view 3D display severely restrict the number of views that can be simultaneously displayed without degrading resolution or increasing display cost unacceptably. An alternative to multiple view presentation is that the position of observer can be measured by using viewer-tracking sensor. It is a very important module of the viewer-tracking component for fluently rendering and accurately projecting the stereo video. In order to render stereo content with respect to users view points and to optically project the content onto the left and right eyes of the user accurately, the real-time viewer tracking technique that allows the user to move around freely when watching the autostereoscopic display is developed in this study. It comprises the face detection by using multiple eigenspaces of various lighting conditions, fast block matching for tracking four motion parameters of the users face region. The Edge Orientation Histogram (EOH) on Real AdaBoost to improve the performance of original AdaBoost algorithm is also applied in this study. The AdaBoost algorithm using Haar feature in OpenCV library developed by Intel to detect human face and enhance the accuracy performance with rotating image. The frame rate of viewer tracking process can achieve up to 15 Hz. Since performance of the viewer tracking autostereoscopic display is still influenced under variant environmental conditions, the accuracy, robustness and efficiency of the viewer-tracking system are evaluated in this study.

Drop Directionality of a Thermal Bubble Jet Print Head

There are plenty of parameters that influence printing quality of inkjet print head such as ejection velocity and directionality of ink droplet. In this paper, relation between droplet printing directionality and physical properties of ink is a major issue. First, theoretical study and numerical simulation would be discussed. With the simulations about ink property, a longer tail and lower flying velocity are occurred due to high viscosity and directionality becomes worse according to the unbalanced pulling and drag effect. Finally, the correlation between surface tension, viscosity and droplet flying directionality would be examined by experimental results