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Computer vision

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Articles 121 - 137 of 137

Full-Text Articles in Electrical and Computer Engineering

Position Recovery And Motion Analysis From Stereo Image Sequences, Yuxin Xie Dec 1991

Position Recovery And Motion Analysis From Stereo Image Sequences, Yuxin Xie

Theses

Based on four stereo images, a new concept of unified optical flow field has been developed recently [3]. It is a generalization of the optical flow in stereo imagery. A set of fundamental equations is established to characterize the unified optical flow field. Another set of equations is then derived from which 3-D structure can be reconstructed and its motion can be analyzed by the use of the unified optical flow field quantities. In this thesis, we use some synthetic images of a rotated conical structure to study and test the theoretical results. The simulation and results are presented, thus …


Studying The Mechanical Response Of Outer Hair Cells To Electric Pulses Using Image Sensors, Wayel F. Mutlag Dec 1991

Studying The Mechanical Response Of Outer Hair Cells To Electric Pulses Using Image Sensors, Wayel F. Mutlag

Theses

The purpose of this research was to develop a way to improve the method used by Dr. Santos-Sacchi at the University of Medicine and Dentistry of New Jersey to detect the motion of the outer hair cell (OHC). As part of the work, the construction and functioning of the OHC are presented and two designs to detect the motion of the boundary of the OHC were investigated.

The first design utilizes the position sensitive detector (PSD) S3932 made by Hamamatsu Inc. This detector, however, required excessive intensity of the optical signal that was not compatible with the operation of the …


Image Analysis Using Gabor Transforms: Correlated With Human Saccadic Movement Data To Identify The Human Visual Search Strategy, Ralph J. St John Dec 1991

Image Analysis Using Gabor Transforms: Correlated With Human Saccadic Movement Data To Identify The Human Visual Search Strategy, Ralph J. St John

Theses and Dissertations

This thesis investigated whether a relationship exists between the Gabor Correlation Coefficient (GCC) magnitudes of fixation points for a set of images viewed by six subjects and the human visual search strategy. A couple of different relationships were investigated. First, the data were analyzed to determine if the GCC magnitudes of human fixation points predicted the time ordered sequence of human fixation points during the performance of a visual search. Second, the data were analyzed to determine if there was a significant difference between the GCC magnitudes of the human fixation points and the GCC magnitudes of a random set …


A Vision System Model, Erik J. Fretheim Jun 1991

A Vision System Model, Erik J. Fretheim

Theses and Dissertations

This dissertation provides four major contributions to the field of vision research. The first contribution is a general vision system model. The model, which blends biological as well as technological methods into a coherent approach to vision, will provide a basis for implementing vision systems. The second contribution of this dissertation is to demonstrate particular implementations of portions of the model. These implementations will include methods for using Gabor wavelets in edge detection, in preprocessing images for use as feature vectors in backpropagation neural networks, and as basis functions in a recognition/reconstruction network, as well as methods for integrating color …


3-D Structure Recovery Using Unified Optical Flow Field Approach, Anees Ahmad May 1991

3-D Structure Recovery Using Unified Optical Flow Field Approach, Anees Ahmad

Theses

Recovery of the 3-D structure that is characterized by an Nth order factorable and/or non-factorable polynomial equation is studied in this thesis. Analytical tools have been employed to analyze and solve the problem. The solution is based on the direct method, which is derived from the unified optical flow field, which, in turn, is an extension of optical flow to spatial image sequences. Least squares formulation has been employed for optimum estimation. The method used does not require the establishment of point to point correspondence, nor the estimation of the optical flow, as an intermediate step.

The theoretical results …


Automatic Infrared And Visual Inspection Of Solder Joints On Pcbs, Jiang Huang May 1991

Automatic Infrared And Visual Inspection Of Solder Joints On Pcbs, Jiang Huang

Theses

This thesis reports the research results of automatic inspection of solder joints on printed circuit boards (PCBs). The previous work on this regard has been advanced significantly in the following three aspects. With the application of some microlens and the principle of geometric optics solder joints of real size are inspected in this work instead of larger simulation solder joints in the previous work. A new set of features is formulated and used for infrared inspection. Consequently, better results have been achieved in this work.

Reasonably good results demonstrate the capability of infrared inspection of solder joints on PCBs. Once …


Direct Recovering Of Composite Surface Using Uoff, Zhesheng Huang May 1991

Direct Recovering Of Composite Surface Using Uoff, Zhesheng Huang

Theses

The research work reported in the thesis is motivated by the problem raised in the computer vision area. It utilizes direct method to recover surface structure of objects in 3-D space from a pair of stereo images. The direct method, compared with optical flow-based approach and feature-based approach, is robust and computationally efficient. However it can only recover planar surface structure so far. A new approach to recover structure from a pair of stereo images based on unified optical flow field (UOFF) is developed recently. It can recover curved surface structure.

In this thesis, the problem of recovering surface structure …


Analysis And Implementation Of A Navigation System Using Vanishing Points In A Generalized Environment, Rolf Schuster May 1991

Analysis And Implementation Of A Navigation System Using Vanishing Points In A Generalized Environment, Rolf Schuster

Theses

The development of accurate sensors is of crucial importance in navigation of mobile autonomous robots. The following master's thesis analyzes the use of vanishing points for robot navigation. Parallel lines in the environment of the robot are used to compute vanishing points which serve as a reference for guiding a robot. To accomplish the navigation tasks, three subtasks are to be performed: detection of straight lines, computation of vanishing points, and robot navigation with vanishing points.

An edge detection algorithm is presented that combines Sobel and Laplacian of Gaussian operators. The algorithm preserves the precision of the Laplacian of Gaussian …


A Machine Vision System With Remote Host, Chieyeon Jason Chen Jan 1991

A Machine Vision System With Remote Host, Chieyeon Jason Chen

Theses

The modem plays an important role in data communication using the Public Swiched Telephone Network. In this thesis, the modem function is merged into a low cost machine vision system based on the Motorola 68HC11. Evalation Board The system comprises the intelligent machine vision con- troller and a remotely located host computer, such as an IBM-PC. It, supports extra long distance communication capability so that the controller and the host can be anywhere in the world where then is a telephone line. Because of the limit of a 2100 bps modem, soft ware data compression is implemented here to save …


Estimating 3-D Motion And Structure Parameters Of A Rigid Planar Object By Establishing Landmark Correspondences, Herman Agustiawan Dec 1990

Estimating 3-D Motion And Structure Parameters Of A Rigid Planar Object By Establishing Landmark Correspondences, Herman Agustiawan

Theses

The application of a landmark based approach in recognizing 3-D rigid planar objects[3] along with two different motion and structure estimation algorithm [21][23] have been studied to perform motion and structure estimation tasks of moving objects. The recognition algorithm is based on a sphericity value derived from affine transformation that maps feature points in the object under observation from first to second view in the 2-D image space. The motion and structure estimation algorithm is based on a unique mapping given four or more feature point correspondences.

More than ten experiments have been done including small and large rigid motions. …


Recovering Surface Structure Using Direct Method, Zhu Ying Dec 1990

Recovering Surface Structure Using Direct Method, Zhu Ying

Theses

A new approach to recovering surface structure from a pair of stereo images is proposed in this thesis. The approach is based on an extension of the concept of optical flow to a spatial sequence of images. z.e., the unified optical field (DOFF). A direct method in spatial domain is developed which is able to recover surface structure that can be characterized by an Nth order polynomial equation. The order N of the surface can be one. a planar surface. or two, a cylindrical or spherical surface. for example. or any number higher than two. This is a big improvement …


A 512 X 512 Random Addressable Variable Resolution Image Sensor, Chakravarthy Yarlagadda Oct 1990

A 512 X 512 Random Addressable Variable Resolution Image Sensor, Chakravarthy Yarlagadda

Theses

This thesis presents the design and layout of a 512 x 512-element with 20μm x 20μm pixels image sensor that emulates the properties of the human eye and is useful in high speed processing of visual data for machine vision applications. The imager will be able to operate with random-address selection in variable resolution or with multiple regions of interest to reduce the number of pixels readout. The selection of the pixels is done by x-y addressing the MOS switches which connect the photodiode pixel to the output through the sense lines. The design of column decoder and row decoder …


Landmark-Based Partial Shape Recognition By A Two-Stage Bam Neural Network, Xianjun Liu Sep 1990

Landmark-Based Partial Shape Recognition By A Two-Stage Bam Neural Network, Xianjun Liu

Theses

In this thesis, we develop a Bitfirectional Associative Memory (BAM) based neural network to achieve partial shape recognition. To recognize objects which are partially occluded, we represent each object by a set of landmarks. The landmarks of an object are points of interest relative to the object that have important shape attributes. To achieve recognition, feature values (landmark values) of each model object are trained and stored in the network. Each memory cell is trained to store landmark values of a model object for all possible positions. Given a scene which may consist of several objects, landmarks in the scene …


Microcomputer-Based Visual Controller And Data Logger System, Xiao-Fang Qi Sep 1990

Microcomputer-Based Visual Controller And Data Logger System, Xiao-Fang Qi

Theses

This thesis paper describes the firmware design, instead of the hardware logic design, makes the machine vision hardware system economical, intelligent and expandable. It shows the construction and testing of a novel remote low speed machine vision control system, which also has functions as data logger and is capable of auto control. The system has 9 analog input channels available, and more. It also has 4 digital output channels for controlling external devices. This work also implemented a way to transfer the grabbed image to a PC/XT. In the 256 graphics mode of the VGA, 64 B&W gray levels can …


Landmark-Based Shape Recognition By A Modified Hopfield Neural Network, Kuowei Li Sep 1990

Landmark-Based Shape Recognition By A Modified Hopfield Neural Network, Kuowei Li

Theses

In this thesis, we introduce a new thethod to achieve partial shape recognition by means of a modified Hopfield neural network. To recognize partially visible object, we represent each object by a set of "landmarks." The landmarks of an object are points of interest relative to the object that have important shape attributes. Given a scene consisting of partially occluded objects, a model object in the scene is hypothesized by matching the landmarks of the model with those in the scene. A measure of similarity between two landmarks, one from a model and the other from the scene, is needed …


A Micro-Based Machine Vision System, Hsueh-Chung Michael Feng May 1990

A Micro-Based Machine Vision System, Hsueh-Chung Michael Feng

Theses

In this thesis, a low-cost general purpose machine vision system based on a personal computer of the PC-XT/AT family and an electronic camera controller based upon a Motorola 6811C11 single-chip microcontroller has been designed and implemented. This work is focused on image formation. The system supports a long distance camera-computer configuration. A picture editor, generic image manipulation software was designed and implemented. A single computer can supervise multiple cameras.


Automatic Infrared Inspection Of Solder Joints On Mounted Circuit Boards, Ken Kekuan Zhou May 1990

Automatic Infrared Inspection Of Solder Joints On Mounted Circuit Boards, Ken Kekuan Zhou

Theses

This thesis reports the research work on automatic infrared and visual light inspections of solder joints on printed circuit boards (PCBs) utilizing an image processing system and statistical pattern recognition techniques.

A small scale image processing system, consisting of a SUN workstation and several DATACUBE modules, is set up for the research. Software packages for imaging, displaying and solder joint inspection are developed and ready for public usage.

The capability of infrared inspection for solder joints on PCBs is demonstrated. The fusing of infrared and visual light imagery for the inspection is shown to offer better results than that obtainable …