Mau-Shiun Yeh

Design of a computer game using an eye-tracking device for eye's activity rehabilitation

An eye mouse interface that can be used to operate a computer using the movement of the eyes is described. We developed this eye-tracking system for eye motion disability rehabilitation. When the user watches the screen of a computer, a charge-coupled device will catch images of the users eye and transmit it to the computer. A program, based on a new cross-line tracking and stabilizing algorithm, will locate the center point of the pupil in the images. The calibration factors and energy factors are designed for coordinate mapping and blink functions. After the system transfers the coordinates of pupil center in the images to the display coordinate, it will determine the point at which the user gazed on the display, then transfer that location to the game subroutine program. We used this eye-tracking system as a joystick to play a game with an application program in a multimedia environment. The experimental results verify the feasibility and validity of this eye-game system and the rehabilitation effects for the users visual movement.

High‐speed TFT LCD defect‐detection system with genetic algorithm

Purpose – The purpose of this research is to develop an automatic optical inspection system for thin film transistor (TFT) liquid crystal display (LCD).Design/methodology/approach – A new algorithm that accounts for the closing, opening, etching, dilating, and genetic method is used. It helps to calculate the location and rotation angle for transistor patterns precisely and quickly. The system can adjust inspection platform parameters according to viewed performance. The parameter adaptation occurs in parallel with running the genetic algorithm and imaging processing methods. The proposed method is compared with the algorithms that use artificial parameter sets.Findings – This system ensures high quality in an LCD production line. This multipurpose image‐based measurement method uses unsophisticated and economical equipment, and it also detects defects in the micro‐fabrication process.Originality/value – The experiments results show that the proposed method offers advantages over other competing methods.

Measurement method of three-dimensional profiles of small lens with gratings projection and a flexible compensation system

Research highlights? We use fringe projection grating measurement system to measure small lens. ? Flexible compensation is carried out for the non-uniform image. ? The sub-pixel technology and polynomial regression method are used for higher resolution. ? The measurement accuracy ranges is from 1 to 2 micro-meter. This study proposed a light field flexible compensation system of fringe projection grating measurement, which uses the fringe projection method to calculate the height of a work piece to be measured. A video device first generates an image without gratings for projection and then projects this image. An imaging device then captures the image and sends it back to the image processing device, so as to form an image with projection information without gratings, as well as an image with gratings. Flexible compensation is carried out for this image in an innovative method. Thus, the images with or without gratings can be clearer. In this way, more accurate 3D contour measurement and reconstructive analytical calculation can be carried out for the work piece to be measured. In the experiments, five small lenses are used for system verification. Then, the 3D contour information is measured to reconstruct the lens profile. The value curvature and focal length of the lens were obtained. This system uses the sub-pixel and polynomial regression method to measure the height of objects throughout the experiments. The measurement accuracy ranges from 1 to 2µm. This method can also provide accurate measurement data for inspection within one second. Moreover, quality verification for the lens module is more convenient.

An automatic evaluation method for the surface profile of a microlens array using an optical interferometric microscope

In this paper, an automatic evaluation method for the surface profile of a microlens array using an optical interferometric microscope is presented. For inspecting the microlens array, an XY-table is used to position it. With a He–Ne laser beam and optical fiber as a probing light, the measured image is sent to the computer to analyze the surface profile. By binary image slicing and area recognition, this study located the center of each ring and determined the substrate of the microlens array image through the background of the entire microlens array interference image. The maximum and minimum values of every segment brightness curve were determined corresponding to the change in the segment phase angle from 0° to 180°. According to the ratio of the actual ring area and the ideal ring area, the area ratio method was adopted to find the phase-angle variation of the interference ring. Based on the ratio of actual ring brightness and the ideal ring brightness, the brightness ratio method was used to determine the phase-angle variation of the interference ring fringe. The area ratio method and brightness ratio method are interchangeable in precisely determining the phase angles of the innermost and outermost rings of the interference fringe and obtaining different microlens surface altitudes of respective pixels in the segment, to greatly increase the microlens array surface profile inspection accuracy and quality.

Polar coordinate mapping method for an improved infrared eye-tracking system

In this paper a polar coordinate mapping method for an improved infrared eye-tracking system is described. In the proposed control system for an eye-tracking device, users do not need to wear any equipment. Rather they just ware an infrared light source and an infrared CCD camera to extract the eye images for the computer to analyze, record the information of the moving traces and pupil diameters, control the mouses cursor and operate many kinds of applied programs. The advantage of this system lies in solving non-contact requirement problems for which the measured system would require whole eye monitoring and a quick response. We also improve the feasibility and the safety of this eye-tracking device by using infrared rays and new coordinate mapping method.

An automatic optical inspection system for measuring a microlens array with an optical interferometric microscope and genetic algorithm

Purpose – The purpose of this paper is to propose an automatic optical inspection system for measuring the surface profile of a microlens array.Design/methodology/approach – The system set‐up was constructed according to the principle of the Fizeau interferometer. After capturing the ring interference fringe images of the microlens with a camera, the diameter, profile information and optical properties were analyzed through a microlens surface profile algorithm using innovative image pre‐processing with a precision of less than 0.09 micron.Findings – By integrating with the genetic algorithm, the XY‐Table shortest moving path of the system is calculated to achieve the purpose of high‐speed inspection and automatic microlens array surface profile measurement.Originality/value – The measurement results of this system were also compared with other systems, including the atomic force microscope and stylus profiler, to verify the measurement precision and accuracy of this system.

A control interface and imaging system for eyeball features measurement

In this study, two white light LEDs were mounted on the upper and lower parts of a CCD camera. By using imaging and lighting control programs, lighting signals were transferred to a monolithic chip light control circuit, so that two white light LEDs could generate instantaneous flash within different preset time intervals. After capturing the images of two flash instants using the CCD camera, the center of the pupil is taken as the center of a circle to measure the rounded edge. The second image is captured when the brightness of the second pulsed light is equivalent to that of the first pulsed light, and the pupil size is the same as that of the first image. The iris region is searched from outside to inside by simply calculating the objective function value at discretely sampled radius and center. The captured images are classified as ‘zone of rejection’, ‘reserved zone’ and ‘merge zone’. A new interpolation method is used for merging two images to complete an image without any reflective dot, as well as a safe lighting design, and double-pulse iris imaging system.