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