Engineering Commons^™

Image Segmentation Using An Annealed Hopfield Neural Network, Yungsik Kim, Sarah A. Rajala

Sarah A. Rajala

Good image segmentation can be achieved by finding the optimum solution to an appropriate energy function. A Hopfield neural network has been shown to solve complex optimization problems fast, but it only guarantees convergence to a local minimum of the optimization function. Alternatively, mean field annealing has been shown to reach the global or the nearly global optimum solution when solving optimization problems. Furthermore, it has been shown that there is a relationship between a Hopfield neural network and mean field annealing. In this paper, we combine the advantages of the Hopfield neural network and the mean field annealing algorithm …

Segmentation-Based Texture Coding Algorithm For Packet Video: A Goal-Oriented Approach, Day-Fann Shen, Sarah A. Rajala

Sarah A. Rajala

The design of an image coder for packet-switched transmission is formulated as a minimization problem. A general set of design requirements is derived and used to design a segmentation-based texture coding algorithm. The segmentation process is performed on a pyramid data structure and uses the just noticeable difference (JND) of the human visual system as the merge criterion. To reduce the bit-rate while maintaining image quality, each region is classified as either texture or non-texture. Texture regions are approximated by a one-dimensional polynomial, while the non-texture regions are approximated by the region's mean intensity. A set of parameters for bit-rate/image …

Tracking Of Unresolved Targets In Infrared Imagery Using A Projection-Based Method, Jae-Ho Choi, Sarah A. Rajala

Sarah A. Rajala

The conventional two-dimensional Hough transform technique is generalized into a projection- based transform method by using the modified Radon transform for estimating a three- dimensional target tracks embedded in a time-sequential set of image frames. The target of concern are dim, unresolved point targets moving along straight paths across a same field of view. Since the target signal-to-noise is low and the spatial extend of the target is less than a pixel, one must rely on integration over a target track which span over many image frames. Instead of processing the entire 3-D data set, a set of projections are …

Segmentation-Based Motion Estimation And Residual Coding For Packet Video: A Goal-Oriented Approach, Day-Fann Shen, Sarah A. Rajala

Sarah A. Rajala

Image transmission via packet switched networks has a significant impact on encoded image data. To develop an efficient image codec for packet video, the goals of image coding are redefined and formulated as an optimization problem. Guided by these goals, a set of design requirements and a new segmentation based coding technique is developed. This approach features region based motion estimation, region based residual coding and region based single frame coding. The performance of the proposed algorithm is evaluated and a packet loss compensation algorithm is presented. As a result, good image quality at very low-bit rates can be achieved.

Visual Sensitivity To Color-Varying Stimuli, Sarah A. Rajala, H. Joel Trussell, B. Krishnakumar

Sarah A. Rajala

We present the results of a study of the sensitivity of the human visual system (HVS) to spatially varying color stimuli. Sinusoidal grating patterns of different spatial frequencies were presented to six observers and the contrast required to just distinguish the pattern from the surrounding uniform field was determined. Tables and curves of contrast (measured in ΔELab) as a function of frequency were generated at different values of; the orientation (horizontal, vertical and diagonal) of the pattern, the average luminance, the x and y chromaticity co-ordinates, and the direction of the variation of the stimulus in color space (luminance, red-green, …

Detection Of Unresolved Target Tracks In Infrared Imagery, Sarah A. Rajala, Loren W. Nolte, James V. Aanstoos

Sarah A. Rajala

Two methods for detecting dim, unresolved target tracks in infrared imagery are presented. Detecting such targets in a sequence of noisy images is very challenging from the standpoint of algorithm design as well as detection performance evaluation. Since the signal-to-noise ratio per pixel is very low (a dim target) and the target is unresolved (of spatial extent less than a pixel), one must rely on integration over target tracks which span over many image frames. In addition, since there is a large amount of uncertainty as to the pattern and location of target tracks, good algorithms must consider a large …

Image Segmentation Using Human Visual System Properties With Applications In Image Compression, Heidi A. Peterson, Sarah A. Rajala, Edward J. Delp

Sarah A. Rajala

Many image compression techniques involve segmentation of a gray level image. With such techniques, information is extracted that describes the regions in the segmented image, and this information is then used to form a coded version of the image. In this paper we present a region-growing-based segmentation technique that incorporates human visual system properties, and describe the use of this technique in image compression. We also discuss the effect of requantizing a segmented image. Requantization of a segmented image is useful because it can lead to a reduction in the number of bits required to code the description of the …

Segmentation-Based Image Coding In A Packet-Switched Network Environment, Sarah A. Rajala, Wonrae M. Lee

Sarah A. Rajala

In this paper, a segmentation-based image coding technique incorporating properties of the human visual system is presented. The approach taken in this research is to first segment an image into regions with spatial similarity and then to define an efficient method for encoding the segmented image data. Furthermore, specific attention is given in this paper to defining the requirements for using a segmentation-based image coder for video transmission over a packet-switched network.

Second Generation Hybrid Image-Coding Techniques, M. Reha Civanlar, Sarah A. Rajala, Wonrae M. Lee

Sarah A. Rajala

Recently, ways to obtain a new generation of image-coding techniques have been proposed. The incorpordtion of the human visual system (IIVS) models and tools of the image analysis, such as segmentation, are two defining features of these techniques. In this paper, an application of the new approach to the classical linear predictive coding (LPC) of images and an HVS based segmentation technique for the second genera-tion coders will be discussed. In the case of LPC, the error image is encoded using an image decomposition approach and binary image coding. This improves the compression ratio keeping the quality nearly the same. …

Implementation Of A Projection Onto Convex Sets Iteration Based Image Coder, M. Reha Civanlar, Sarah A. Rajala, Thomas K. Miller

Sarah A. Rajala

Projection onto convex sets iteration based image coding, where efficiently encodable sets are used to describe an image, is a recent approach to image compression. The technique allows the use of a variety of sets to encode an image. The focus of this paper, however, will be on two particular sets: the set of images whose cosine transform is known for certain frequencies and the set of images which are nonzero over a specified region. These sets can be used to encode interframe difference pictures of video teleconferencing images. A drawback of this new type of codec is its computational …

New Solution For Frequency And Pixel Domain Coding Using Convex Sets, Pete Santago, Sarah A. Rajala

Sarah A. Rajala

This paper describes a new algorithm for combining spatial and frequency domain information about an image in order to improve coding. The algorithm utilizes successive projections onto two non-intersecting sets in order to determine the optimal frequency domain coefficients to transmit given some known spatial information. This technique is best suited to fixed block size transform coders and builds on the techniques used in previous work.

Technique For Video Compression By Projection Onto Convex Sets, P. Santago, Sarah A. Rajala

Sarah A. Rajala

This paper describes a video compression technique which utilizes the alternating projection theorem for convex sets. The image to be transmitted is determined to be in certain convex sets and parameters defining these sets are sent. The receiver can then use the method of successive projections to locate an image which is in the intersection of the sets. If the intersection is small then the image determined should be close to the desired image. The coder can be made more robust by easily adding additional convex sets or using it in conjunction with other coding schemes such as motion compensation.

An Evaluation Of The Directed Flow Graph Methodology, Wesley E. Snyder, Sarah A. Rajala

Sarah A. Rajala

The purpose of this project was to evaluate the applicability of the Directed Graph Methodology (DGM) to the design and analysis of special purpose image and signal processing hardware. To this end, a special purpose image processing system was designed and described using DGM. The design, suitable for VLSI, implements an innovative region labeling technique. The utility of DGM was evaluated using this design.

Turbine Blade Image Processing System, Neal S. Page, Wesley E. Snyder, Sarah A. Rajala

Sarah A. Rajala

A vision system has been developed at North Carolina State University to identify the orientation and three dimensional location of steam turbine blades that are stacked in an industrial A-frame cart. The system uses a controlled light source for structured illumination and a single camera to extract the information required by the image processing software to calculate the position and orientation of a turbine blade in real time.

A Study Of Real-Time Computer Graphic Display Technology For Aeronautical Applications, Sarah A. Rajala

Sarah A. Rajala

The development, simulation, and testing of an algorithm for anti-aliasing vector drawings is discussed. The pseudo anti-aliasing line drawing algorithm is an extension to Bresenham's algorithm for computer control of a digital plotter. The algorithm produces a series of overlapping line segments where the display intensity shifts from one segment to the other in this overlap (transition region). In this algorithm the length of the overlap and the intensity shift are essentially constants because the transition region is an aid to the eye in integrating the segments into a single smooth line.

Adaptive Nonlinear Image Restoration By A Modified Kalman Filtering Approach, Sarah A. Rajala

Sarah A. Rajala

An adaptive nonlinear Kalman-type filter is presented in this dissertation for the restoration of two-dimensional images degraded by general image formation system degradations and additive white noise. A vector difference evaluation model is used to model the degradation process. The object plane distribution function is partitioned into disjoint regions based on the amount of spatial activity in the image, and difference evaluation models are used to characterize the object plane distribution function.

It is shown that each of the regions can be uniquely characterized by their second order statistics. The autocorrelation function for each region is then used to determine …