Showing papers on "Change detection published in 1985"

Detection of Abrupt Changes in Signals and Dynamical Systems

Abstract: On -line detection of jumps in mean.- Detection of abrupt changes in dynamic systems.- Two examples of application of the GLR method in signal processing.- Advanced methods of change detection: An overview.- III - Design of algorithms for change detection : Likelihood-oriented approaches.- Off-line statistical analysis of change-point models using non parametric and likelihood methods.- The two-models approach for the on-line detection of changes in AR processes.- Sequential detection of changes in stochastic systems.- The local method applied to the robust detection of changes in the poles of a pole-zero system.- Redundancy relations and robust failure detection.- Estimation-based approaches to rhythm analysis in electrocardiograms.- On line segmentation of speech signals without prior recognition.- Application of change detection theory to seismic signal processing.

Change Detection and Tracking Using Pyramid Transform Techniques

Abstract: An automated, or "smart", surveillance system must be sensitive to small object motion wherever it may occur within a large field of view. The system must also be capable of distinguishing changes of interest from other image activity or noise. Yet the data processing capabilities of practical systems is often quite limited. To achieve these performance objectives at a low data rate, a pyramid based image preprocessor has been constructed that can compute frequency tuned "change energy" measures in real time. A microprocessor then examines a relatively small set of these measures and follows a foveal search strategy to isolate moving objects for tracking or for more detailed analysis.

Application of change detection theory to seismic signal processing

Abstract: In this paper, we describe a set of algorithms for on-line signal processing of earthquakes occuring at a distance Δ from a seismic station such that: 200 ⩽ Δ ⩽ 1000km. We discuss the application of sequential change detection algorithms and a posteriori maximum likelihood estimation for these signals.

Rectification and Registration of Remotely Sensed Data.

Abstract: : An important problem in any onboard imaging system is the rectification and registration of images generated by onboard sensors. Accurate registration is a key requirement for detecting changes (in position, brightness, texture, boundary, etc.), from one sensed image to the next, as well as classification of data for intelligence gathering and vehicle guidance. This report discusses techniques of finding match points in pairs of images and performing geometric corrections and unwarping to compensate for systematic and random variations in the flight path, ephemeris, and sensor response. Techniques of resampling and interpolation of image data are reviewed, and the particular characteristics of sensors operating over a wide spectrum from visible through infrared and microwave are discussed. Particular attention is given to the rectification and registration of synthetic aperture radar (SAR) imagery, and several future study tasks on this specialized area are outlined. Originator-supplied keywords: Image rectification, Image registration, Mapping, Geometrical distortions, Signal processing, Artificial intelligence, Resampling, Change detection, Multisensor, Synthetic aperture radar imagery.

System and circuit for extracting biphase code clock

Abstract: PURPOSE:To alway attain stable clock detection with a simple system by taking exclusive OR between an input signal subject to changing point detection signal biphase coding where the binary state is inverted alternately at the point of time of code change and the output of a flip-flop. CONSTITUTION:A code change detection circuit 701 detects the code change of 1 0 of the input signal 702. A code change detection circuit 703 detects the code change of 0 1 of the input signal 702. A set/reset flip-flop 706 uses one output signal of code change detection circuits 701, 703 as the set input signal and the other output signal as a reset input signal. An exclusive OR circuit inputs the output signal 707 of the flip-flop 706 and the input signal subject to biphase coding so as to OR them exclusively.

Vegetation change detection from NOAA polar orbiting satellites

Abstract: A Method is proposed for detecting vegetation change using global area coverage data from the NOAA-7 Advanced Very High Resolution Radiometer. Other methods of vegetation change detection, such as baseline images, are discussed, but not demonstrated. Vegetation Change Detection Images are produced by combining three separate weekly composites of Channel 2 minus Channel 1 AVHRR data. This compositing method takes the highest value of the differenced data for each week period and each pixel location. Three such weekly composites red imaged by individual red, green and blue CRT color guns respectively and then combined to form a color composite. The Vegetation Change Detection Image has 20 km resolution. It can be used to show an entire continent on a single image when the data point to CRT pixel ratio is 1:1. The vector vegetation change (magnitude and direction) is depicted by the color pattern resulting from the relative amount of red, green and blue placed in the pixel due to the individual weekly color composites. If there is no greenness change at a pixel location the amount of red, green and blue will be the same and a gray scale color results. The VCDI could provide a timely “first alert” for identifying regional and global agricultural changes.

The local method applied to the robust detection of changes in the poles of a pole-zero system

Abstract: In this chapter, we investigate a non classical change detection problem, for which there is a strong coupling effect between nuisance parameters and parameters to be monitored. As maximum likelihood methods cannot be used in this case, we derive a so-called instrumental statistics which, together with a local testing approach, gives a new test of x2 type. The extension of this test for the problem of diagnosis is also described.