Jaehong Lim

A Fast Center of Pupil Detection Algorithm for VOG-Based Eye Movement Tracking

This paper proposes an algorithm that has been developed for the video-oculograph method. It is used to detect the center of the pupil, extracted from a captured image of an eye acquired by using a CCD camera and a computer with image grabber. The captured eye image is 640 by 480 pixels in size at 8 bits per pixel, in depth. The center of the pupil area could be obtained by applying the proposed algorithms for the threshold of the captured gray-scale image, for image enhancement and noise removing techniques even though the pupil area was partially covered by eyelashes and an eyelid

Development of a classification algorithm for butterflies and ladybugs

In this study, the classification of the insects family from an image is performed by using the pattern recognition technology. Classifying an insect by class, family, genus cannot be realized without basic knowledge and the use of an encyclopedia. This process is based on simple comparison analysis. Performing this work manually, comparing each image individually is in efficient. Eventually the computer with camera and program could automatically detect two insects class pattern through algorithm. In the first stage the ladybug and the butterfly are used. Their feature pattern is distinguished from an unspecific image and then the data is used to develop the distinction-algorithm. Factors to determine the classification are its size, color, antennae and shapes of shells. The image which is obtained with the digital camera is built up out of pixels. For each pixels the color, position and size is known. Back-planes feature and antennae are detected by edge detection and chain-code analysis

A Fast Eye-Movement Tracking Using Cross-Division Algorithm

This study shows that a precise eye tracking and pupillometer system, neither interfering visual field nor influenced by head movement, can be implemented by analyzing first Paikinje image of visual field which has a few reference points. If two or more reference points are sited around the center of visual field, then eye camera captures the overlapped image of reference points and pupil. Four high intensity infra-red light-emitting diodes (IR LEDs) are used as reference points in this study not to disturb the subjects attention. These reference points appear as four highlighting points in the captured pupil image. The actual gazing point can be calculated by finding the distance between the center of these four reference points and pupil center and angle. Head movement causes some shift of location of pupil and reference points in the same direction and with the same amount hence does not change the relation of them. This technique can afford to make a system that has fast sampling time and high resolution without extra servo-mechanism to chase subjects head movement.

Preliminary Study for Gait Phases Detection to Develop a Rehabilitation Equipment for Hemiplegic Patients

Preliminary experiment for analyzing weight shift during gait phases for hemiplegic patients was carried out to develop rehabilitation equipment. A gait phase detection system using pressure sensors was developed and the experiment was carried out for eight hemiplegic patients and normal adult. The weight shift during gait phases for a normal adult showed symmetrical for left and right footing phase, but that for the hemiplegic patients showed asymmetrical footing phase. However, it gave sufficient information to discriminate between left and right footing phases

An Algorithm for Real-Time Eye-Movement Tracking with Free Head Movement

A fast algorithm for real-time eye-movement tracking with free head movement based using image subtraction was proposed in this study. for this purpose four reference points consisted of infra-red LEDs were used to compensate the subjects head movement and a fast gazing point detection algorithm was developed and applied to determine the subjects gazing point by comparing the relative distance and angle between the center points of the pupil area. the size of input image was scaled down to 1/16 to detect the eye and its neighbor area quickly and the theorem for a circumcenter of a triangle was applied to detect the center of the pupil

A Measuring System for Coronary Pulse Wave Velocity

Pulse wave velocity (PWV) is a basic parameter in the dynamics of pressure and flow wave traveling in arteries. But it is difficult to measure the pulse wave transmission time between coronary arterial proximal and distal point by manual method using the graph on which pulse wave and ECG are recoded. The system that can measure PWV was developed and the experiment was carried out for one patient to validate the accuracy of the measured coronary arterial PWV. The average value of the measured coronary arterial PWV was 936.571±105.161 cm/sec.

A VOG-based Gazing Point Detection Algorithm

Information regarding to eye movement is applied to many fields such as psychology, ophthalmology, physiology, rehabilitation medicine, web design and human-machine interface. So far many technologies have been developed to detect the eye movement and most widely used techniques include EOG (electro-oculograph), Purkinje image tracker, scleral search coil technique, VOG (video-oculograph). This study aims at development of algorithms that can detect and track the gazing point by comparing the relative coordinates of the center of a pupil in the eye image acquired by a CCD camera and image grabber and the center of the four infra-red reference points image reflected from the eye. The size of input image was scaled down to 1/16 to detect the eye and its neighbor areas quickly. An approximative eye position is calculated from this scaled-down image for the detection of precise position of the center of pupil and four reference points reflected from the eye. These four reference points are created by infra-red illumination not to disturb subject’s attention to the target. The infra-red lamps were turned on for the time duration of one frame of image and turned off for the next one frame so that the four reference points reflected from the eye could be extracted easily by comparing these two images. The theorem for a circumcenter of a triangle was applied to detect the center of pupil. The gazing point could be calculated by the relative distance and angle between the center of pupil and the center of four reference points in the captured image.

A Diagnosis System for the Spinal Column Nerve Damaged Patients

Visible evidence of spinal column damage is only apparent in 14% of the patients who receive spinal damage. We use a humidity sensor array. The humidity sensor (HDP-05) is arranged and attached to pre-assigned regions along the spinal column nerve of the actual patient. Applying pressure to the urinary bladder causes the patient to sweat. It is possible to determine which spinal column autonomic nerve is damaged in a region by humidity value. But also have some problem is that sometimes the damaged region has same value as a normal region. If will find a better attachment method and a more sensitive sensor could be found the results will be better and more precise

Study to find an interrelationship with position of the pupil and an eyelid to extraction of point of gaze

This paper proposes an algorithm that has been developed for the video-oculograph method. Knowing the change of eyelid shape, we detect a center of pupil for extraction of a point of gaze. It is used to detect the center of the pupil, extracted from a captured image of an eye acquired by using a CCD camera and a computer with image grabber. The image is 640 by 480 pixels in size. The program controls the image easily by using the binary image from the captured image grabber. The image removed noise, the reflected light from the pupil or partially covered by eyelashes and an eyelid, by using the image enhancement method. And boundary of eyelid is extracted using the obtained outline around eye.

Development of a self-tutoring multimedia contents for microcontroller instruction set

In this paper, we have developed a new educational system that more easier understanding basic concept than current contents, for biomedical engineering who study microcontrollers or microprocessors that is found in modern medical equipment. The developed tutoring system utilized multimedia contents and reduced a great disparity of education quality. It also provides movie clips, graphic animation, narrations, which contains graphic and text document. Movie clips were produced by using Win Cam (Mirion Systems), and graphic animation were implemented by using FLASH MX software (Macromedia Inc.) and Action Script, GIF graphic files and Power Point Techniques. This tutoring system includes the basic concept of microcontroller-based system, entire execution process for the each instruction of the instruction set, development of small-sized programs, understanding of operations, control of built-in peripherals and design techniques of simple application programs.