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Full-Text Articles in Computer Engineering
Simple High-Quality Lossy Image Coding Scheme, Shaolin Bi, Khalid Sayood
Simple High-Quality Lossy Image Coding Scheme, Shaolin Bi, Khalid Sayood
Department of Electrical and Computer Engineering: Faculty Publications
A simple yet efficient image data compression method is presented. This method is based on coding only those segments of the image that are perceptually significant to the reconstruction of the image. Sequences of image pixels whose gray-level differences from the pixels of the previous row exceed two prespecified thresholds are considered significant. These pixels are coded using a differential pulse code modulation scheme that uses a 15-level recursively indexed nonuniform quantizer for the first pixel in a segment and a 7-level recursively indexed nonuniform quantizer for all other pixels in the segment. The quantizer outputs are Huffman coded. Simulation …
Gyroless Line-Of-Sight Stabilization For Pointing And Tracking Systems, Marcelo C. Aigrain
Gyroless Line-Of-Sight Stabilization For Pointing And Tracking Systems, Marcelo C. Aigrain
Department of Electrical and Computer Engineering: Faculty Publications
A new platform stabilization approach is described where miature, low-cost, linear accelerometers are used (instead of gyroscopes) for line-of-sight (LOS) stabilization. This is accomplished by placing the accelerometers at strategic locations and combining their outputs so that angular motion is determined from linear acceleration measurements. The control system uses the sensed angular accelerations to generate movement commands for the gimbal servomotors in the stabilization platform. This counterrotates the imaging device to stabilize its LOS. The use of accelerometers allows the servo system to operate in an acceleration control mode, which is more desirable than position or velocity control modes, typical …