Opas Chutatape

• Rangsit University

A deformable-model based approach is presented in this paper for robust detection of optic disk and cup boundaries. Earlier work on disk boundary detection up to now could not effectively solve the problem of vessel occlusion. The method proposed here improves and extends the original snake, which is essentially a deforming-only technique, in two a...

This paper presents a novel deformable-model-based algorithm for fully automated detection of optic disk boundary in fundus images. The proposed method improves and extends the original snake (deforming-only technique) in two aspects: clustering and smoothing update. The contour points are first self-separated into edge-point group or uncertain-poi...

Three-dimensional (3-D) visualization of the optic nerve head (optic disk) is very useful for clinical applications. It allows clinicians to measure the disk parameters more accurately and thus make the pathological diagnosis and progression monitoring easier. This paper describes an automatic, precise, 3-D optic nerve head reconstruction method fr...

The three dimensional (3-D) visualisation of the optic disc in true colour will give essential meaning in clinical application. It is not only useful for clinicians in the evaluation of the condition of the optic disc, but it also simplifies the pathological diagnosis and disease progression monitoring. This paper describes a complete 3-D optic dis...

The problem of automatically locating the fovea, a spot located in the center of the macula and responsible for sharp central vision, on the retinal surface image is considered. The uniqueness of the strategy presented here is the relatively small amount of computational expense of a quick and robust method conducive to real-time applications. The...

Optic disk is one of the main components on retina. It is an indicator of various ophthalmic pathologies. This paper presents a novel algorithm to segment the optic disk, based on snake model. The proposed method improves and extends original snake technique in two aspects: clustering and smoothing update. The contour first deforms to the location...

Bright lesions in the form of exudates and cotton wool spots while dark lesions consisting of hemorrhages are main evidences of background diabetic retinopathy that require early detection and precise classification. Based on different properties of bright lesions and dark lesions, bottom-up and top-down strategies are applied respectively to cope...

This paper describes a method of three-dimensional (3-D) optic disk reconstruction from a pair of stereo images. This is achieved through the implementation of various procedures that further enhance the accuracy including camera calibration, constraint-based combined registration, dense-depth recovery, and eye-optics inclusion. A combination of tw...

A new algorithm to detect the exact optic disk boundary, based on deformable model, is proposed in this paper. The energy function for deformation is defined as a combination of local energies. The proposed method modified the original snake technique in two aspects: clustering the contour points into edge-point group or uncertain-point group after...

Hemorrhages are main evidences of background diabetic retinopathy and early detection is essential for an effective treatment. In this paper, a top-down strategy is applied to detect hemorrhages. After color normalization preprocessing stage, an evidence value for every pixel is calculated by SVM. The SVM classifier uses features extracted by combi...

In this work, we propose a perceptual model based technique for embedding patient information in a medical image. The distortions in the diagnostic information-content, which will arise due to data embedding, can be controlled using a Perceptual Quality Measure (PQM). A Perceptual Quality Distortion Measure (PQDM) has been defined to measure the vi...

Color retinal photography is an important tool to detect the evidence of various eye diseases. Novel methods to extract the main features in color retinal images have been developed in this paper. Principal component analysis is employed to locate optic disk; A modified active shape model is proposed in the shape detection of optic disk; A fundus c...

In this work, we propose a wavelet-based technique for embedding medical data in a medical image. In the spectral domain, the patient data are embedded into the wavelet coefficients of the host image. A diagnostic distortion measure (DDM) has been defined to measure the visible distortions between the original image and the embedded image. The perf...

Three dimensional (3-D) visualization of optic disk surface is very useful for clinical application. It allows clinicians to measure the disk parameters more accurately and thus make the diagnosis easier. This work describes an automated 3-D optic disk reconstruction method from a pair of stereo images for which efficient steps including sparse-ima...

This paper considers the problem of locating the optic nerve center, a place where the blood vessel and nerve emanate. Our algorithm first identifies the main blood vessel, which is characterized by large width and dark red color, by using amplitude modified second-order Gaussian filter. The optic nerve center is then found by tracking along this m...

A new approach to automatically extract the main features in color fundus images is proposed. The optic disk is localized by principal component analysis (PCA) and its shape is detected by a modified active shape model (ASM). Exudates are extracted by the combined region growing and edge detection. A fundus coordinate system is further set up based...

Two photogrammetric camera calibration methods based on two calibration objects, i.e., 3-D and planar calibration objects, were used with a nonmydriatic fundus camera and the results were presented. Experimental results show that lens distortion plays a major role in the system error contribution and it is therefore necessary to be taken into accou...

A new algorithm to automatically detect the boundary of optic disk in color fundus images is proposed. The optic disk is located by principal component analysis (PCA) based model, which is employed to initialize active shape model (ASM) to detect the disk boundary. ASM is modified with two aspects: one is the self-adjusting weight in the transforma...

Existing medical image acquisition, storage, retrieval, and diagnosis procedure currently practiced in clinics or hospitals can be further enhanced by incorporating the ever increasingly powerful Internet technologies. In this paper, a concept of online database for remote access to medical image database is presented along with the design methodol...

A new method to Automatically locate the optic disk and estimate its shape in color retinal images is proposed. Principal component analysis (PCA) is applied to the candidate regions at various scales to locate the optic disk. The minimum distance between the original retinal image and its projection onto "disk spaces" indicates the center of the o...

This paper describes how a Genetic Algorithms (GA) based optimization method is used specifically to register two ocular fundus images having either temporal or multimodal difference. Ocular fundus images of the same eye are generally compared by ophthalmologists to find differences due to growth of abnormalities in retina for diagnosis, follow-up,...

This paper describes how a Genetic Algorithms (GA) based optimization method is used specifically to register two ocular fundus images having either temporal or multimodal difference. Ocular fundus images of the same eye are generally compared by ophthalmologists to find differences due to growth of abnormalities in retina for diagnosis, follow-up,...

In this paper, the fitness of estimating vessel profiles with Gaussian function is evaluated and an amplitude-modified second-order Gaussian filter is proposed for the detection and measurement of vessels. Mathematical analysis is given and supported by a simulation and experiments to demonstrate that the vessel width can be measured in linear rela...

Many current telemedicine systems use hardwired fixed lines, like ISDN, LAN, and even ATM access for their data transmission and real-time telemonitoring. With the advent of new wireless broadband technologies, the migration of telemedicine applications to the wireless domain is imminent. Mobile telemedicine is a newly emerging yet promising area,...

A polar coordinate system for retinal fundus image is set up based on the novel technique in the model-based, automatic localization of various landmark features of the retinal image. The technique begins with the detection of optic disk location by the Principal Component Analysis (PCA), the optic disk boundary detection by a point distribution mo...

On the research work leading to automatic analysis of retinal fundus images, the knowledge of the optic disk location is essential, and a new method to locate the optic disk automatically is proposed. The candidate regions are first determined by clustering the brightest pixels in the intensity image. Principal component analysis (PCA) is then appl...

The line jitter of CCD images can considerably influence the precision and resolution of a high-accuracy vision-based automated inspection system. We report the experimental studies on the line jitter of CCD images. By use of a method of Harr wavelet transform, correlation, and statistics analysis to detect the line jitter of subpixels, the experim...

Automated analysis of vessel morphology is valuable in diagnosis since it can provide measurable abnormalities in diameter and tortuosity that reflect systemic or local ocular disease. Although the center point of vessel can be easily detected with matched filter, the diameter cannot be obtained from the readily available convolution result in the...

An approach to abnormality detection from colour fundus images for an automated mass screening system is proposed in this paper, which uses the object-based colour difference image. Four colour models, viz. RGB, Luv, Lab and HVC, are evaluated based on hand-labelled feature maps, and Luv and Lab are selected for computing the colour difference beca...

Automated analysis of vessel morphology is valuable in diagnosis since it can provide measurable abnormalities in diameter and tortuosity that reflect systemic or local ocular disease. Although the center point of vessel can be easily detected with matched filter, the diameter cannot be obtained from the readily available convolution result in the...

Diabetic retinopathy is the leading cause of the blindness in the working age population. If the disease is detected early and treated promptly, much of the visual loss can be prevented. This paper describes the development of an automatic fundus image processing and analytic system to facilitate diagnosis of the ophthalmologists. The algorithms to...

The manner by which the short line segments are connected to approximate the ideal straight line in digital image space will influence the performance of Hough transform. The peak spreading can be avoided when Δρ satisfies a certain condition. Consequently, a new approach called a variable-Δρ Hough transform having Δρ as a function of θ is proposed...

The heavy burden of computational complexity and massive storage requirement is the drawback of the standard Hough transform (HT). Besides, the Hough transform is also quite a “blind” algorithm, which is much inferior to the intellectual mechanism of human’s visual recognition. To overcome these weaknesses of Hough transform, many modified approach...

The essential characteristics to achieve the reliable and useful rate of success in the automatic recognition of vehicle license-number using machine vision are the suitably controlled environmental setting and high recognition speed. Prior to the OCR operation, the location of license numberplate has to be found and the alphanumeric characters hav...

This paper presents a segmentation technique based on multiple threshold values determined by fuzzy logic and information entropy principle to extract alphanumeric characters from general scene images, and its parallel implementation in a cluster of personal computers in a local area network. In this approach, the scene images are segmented into va...

Detection and tracking algorithms of the blood vessel network in the retinal images are proposed. Two main groups of algorithms are employed for this task, i.e., scanning and tracking. According to the known blood vessel feature, a second-order derivative Gaussian matched filter is designed and used to locate the center point and width of a vessel...

This paper presents a segmentation technique based on fuzzy logic and information entropy principle to extract alphanumeric characters from general scene images. In this approach, the scene images are segmented into various regions based on fuzzy entropy method. A coarse searching technique is then implemented to locate potential character regions,...

This paper describes an automatic retinal image analysis system which can be used for the mass screening of diabetic retinopathy patients. Fundus photographs were scanned and processed sequentially to identify the optic disk and the fovea through a Hough transform, to trace the blood vessels by a Gaussian filter and finally to detect the exudates u...

This paper describes the implementation of the NETBIOS and the Novell's IPX protocols for the server independent, peer-to-peer communications with the objective for real time control applications in manufacturing systems. The performance evaluation based on the Ethernet data link and the connectionless communications is presented. It is shown quant...

Among the wide ranging forms of medical diagnostic modalities, blood analysis is one of the most common, and is likely to become more important as various blood related diseases become more pervasive. Histogram-based methods are among the most popular for thresholding a biomedical image of blood aggregates in a plastic tube. However, these methods...

C Y Teo received a BSc (Eng) in electrical 0120engineering from the National Taiwan University, Taiwan in 1971 and an MSc in electrical machines and power systems from the University of London in 1974. He has worked in many areas of computer applications in power systems since he joined as a research assistant with Imperial College, UK in 1973 and...

This paper describes the implementation of the NetBIOS and the Novell's IPX protocols for the server independent, peer-to-peer communications with the objective for real-time control applications. The results of evaluation for both protocols based on the Ethernet data link using the connectionless-oriented communications is later presented. It is s...

This paper describes a multi-tasking operation using interrupts in MS-DOS for PC-based supervisory control and data acquisition (SCADA) systems. The structure of a generalized interface circuitry is formulated to serve as a standard interface for SCADA application programs to be independent from the types of hardware interface. Communication betwee...

The authors present a technique for the segmentation of range images. It tends to be a hybrid approach that combines edge detection and region growing techniques for accomplishing the task of segmentation. The surface coherency property of range data is an important attribute of the technique. The cross-breeding approach produces a segmentation map...

This paper describes a generalized interface handler implemented on a PC-based SCADA system which can handle up to a total of 512 digital points and 512 analog points. It is aimed to provide a standard structure for SCADA application program to be independent from the interfacing hardware. Using the same data structure, a multi-tasking operation ha...

The modern manufacturing facility uses the multiple robot assembly system (MRAS) which consists of two or more robots that cooperate in accomplishing a complex manufacturing task within a manufacturing cell to improve efficiency. As most MRAS tasks are complex in nature, the processes involved in the execution of operations are usually implemented...

Not Available

A microcomputer-based stepper motor motion controller was developed to address the performance limitations and relative inflexibility of many microprocessor-based systems. This motion control system features two-axis closed-loop control, high pulse rate in support of microstepping translators/drivers, sensor integration, and complex trajectories an...

A distributed, analogue/digital data acquisition controller implementing the unique programmable counter array (PCA) available on the 80C51FA microcontroller together with its automatic address recognition as a low level communication protocol has been developed. Emphasis is placed on the design of a more flexible distributed controller which is ca...

The development of a prototype system of an integrated energy automation center for supervisory control and data acquisition (SCADA) and energy management of an entire area integrating power distribution network buildings and individual plants is summarized. The development of a distributed controller for a field interface, local system, central sy...

A sensor system to facilitate the easy access of temperature signals and digital operating condition signals from refrigerated containers has been designed, fabricated and tested. The sensor system developed is capable of accurately accessing the signals. With the use of some commercially available analog signal processing modules the RMU (remote m...

The objective of this project is to develop new techniques for computer-based image processing and analysis of clinical endoscopic colour images to facilitate cancer detection. RG 60/96

In recent years, minimally invasive endoscopic procedures have been increasingly employed for diagnostic and surgical purposes, thus decreasing the in-hospital stay period and time for recovery of the patient. These procedures are manually performed and analysed by expert endoscopists such as in the gastrointestinal and respiratory cases. Hence the...

The color fundus images which can be obtained noninvasively from individuals plays an important role in the mass screening and diagnosis of eye diseases, especially the diabetic retinopathy. However when there is a large number of images to inspect, diagnose, and annotate, it becomes a burden that demands a considerable amount of time for an ophtha...

An interactive PC-based program package consisting of root locus, time, and frequency domain signal processing vby Fast Fourier Transform and Inverse Fast Fourier Transform (FFT-IFFT), dynamic system simulation, screen plotting, on-screen graphic editing and graphic capturing programs is developed. RP 17/83

This report summarizes the applied research work of a prototype system using microcomputer for SCADA applications and real-time energy management for commercial building and industrial plants. RP 19/88