A new radar glint model has been created to evaluate the terminal characteristics of the Advanced Medium Range Air-to-Air Missile (AMRAAM). This model was designed to use deterministically based glint parameters that ...
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ISBN:
(纸本)081941185X
A new radar glint model has been created to evaluate the terminal characteristics of the Advanced Medium Range Air-to-Air Missile (AMRAAM). This model was designed to use deterministically based glint parameters that develop accurate glint characteristics for real-time simulations. The model uses a deterministically derived data table to specify the first order glint statistics; it then generates random glint characteristics which are a function of target type, target orientation, and the target rotation rate. This combination allows the model to develop radar cross section and glint data to drive the real-time AMRAAM simulation program.
In this paper, we investigate the use of linear filtering techniques in the exploitation of hyperspectral imagery. In particular, we focus on applications of the simultaneous diagonalization (SD) filter to hyperspectr...
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ISBN:
(纸本)0819411779
In this paper, we investigate the use of linear filtering techniques in the exploitation of hyperspectral imagery. In particular, we focus on applications of the simultaneous diagonalization (SD) filter to hyperspectral image analysis. The SD filter can be designed to enhance a particular feature with a known spectral response pattern and suppress undesired features. The filter is used to enhance surface features in two AVIRIS scenes acquired from the Forest Ecosystem Dynamics (FED) flightline on September 8, 1990. A spectral distance algorithm is also applied to this hyperspectral data to enhance surface targets with similar spectral response patterns. Although no detailed ground information was utilized, targets were selected by image interpretation methods and included an urban/disturbed site, and a wetland bog area, and a northern vegetation type (mixed hardwood). Both the SD filter and the spectral distance algorithm are able to effectively separate these classes of ground features from others.
This paper describes an approach for employing an Assumption Truth Maintenance System (ATMS) to support a tri-service algorithm development environment. A truth maintenance system provides a mechanism for tracking ass...
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ISBN:
(纸本)0819411930
This paper describes an approach for employing an Assumption Truth Maintenance System (ATMS) to support a tri-service algorithm development environment. A truth maintenance system provides a mechanism for tracking assumptions and logical propositions, and recognizing contradictions. The higher order logic embodied by the truth maintenance system adds value and functionality to the tool set for applications programming. The first section of this paper describes an implementation of an ATMS in the Army's MAXIMIZE (matrix for algorithm exploration, optimization and evaluation) system. The latter part of the paper describes preliminary results of an integrated truth maintenance system to assist image understanding.
Laser induced retinal lesions are used to treat a variety of eye diseases such as diabetic retinopathy and retinal detachment. An instrumentation system has been developed to track a specific lesion coordinate on the ...
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ISBN:
(纸本)0819411043
Laser induced retinal lesions are used to treat a variety of eye diseases such as diabetic retinopathy and retinal detachment. An instrumentation system has been developed to track a specific lesion coordinate on the retinal surface and provide corrective signals to maintain laser position on the coordinate. High resolution retinal images are acquired via a CCD camera coupled to a fundus camera and video frame grabber. Optical filtering and histogram modification are used to enhance the retinal vessel network against the lighter retinal background. Six distinct retinal landmarks are tracked on the high contrast image obtained from the frame grabber using two-dimensional blood vessel templates. The frame grabber is hosted on a 486 PC. The PC performs correction signal calculations using an exhaustive search on selected image portions. An X and Y laser correction signal is derived from the landmark tracking information and provided to a pair of galvanometer steered mirrors via a data acquisition and control subsystem. This subsystem also responds to patient inputs and the system monitoring lesion growth. This paper begins with an overview of the robotic laser system design followed by implementation and testing of a development system for proof of concept. The paper concludes with specifications for a real time system.
In the past, NASA tracking systems which provided range and bearing to targets have primarily been radar based. Advanced projects such as unmanned missions to the moon and Mars need automated rendezvous and capture (A...
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ISBN:
(纸本)081941185X
In the past, NASA tracking systems which provided range and bearing to targets have primarily been radar based. Advanced projects such as unmanned missions to the moon and Mars need automated rendezvous and capture (AR&C) to reduce operating costs and improve mission reliability. In the tracking Techniques Branch at Johnson Space Center we are investigating the feasibility of a stereo digital image based sensor for AR&C. This system differs from traditional stereo systems in two significant ways. First, a passive cooperative target is used to calculate the range to three specific points as opposed to calculating a range map of the entire scene. The second unique feature is the image processing algorithms that are used to identify the target. In this paper the sensor's performance is compared to preliminary AR&C operating range and accuracy requirements. A theoretical error model is presented that predicts the sensor's accuracy as a function of range.
A new approach to calculate the inverse kinematic functions whose domain of solution is not limited to the manipulator's workspace is introduced. Using this approach every point in the Cartesian space leads to a r...
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ISBN:
(纸本)0819412007
A new approach to calculate the inverse kinematic functions whose domain of solution is not limited to the manipulator's workspace is introduced. Using this approach every point in the Cartesian space leads to a real solution when used as data for the inverse kinematic problem. The solution gives the minimum distance between the end-effector and the prescribed point in the Cartesian space for a given orientation of the end-effector. The proposed inverse kinematic functions are of great interest for tracking, approach, and catching operations where the object to be reached or tracked by the manipulator is inside or outside the robot's workspace.
This paper describes how optical sensor signal processing and data association methods that have been developed for Aerospace applications can be applied to the traffic monitoring function of Advanced Traffic Manageme...
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ISBN:
(纸本)0819411906
This paper describes how optical sensor signal processing and data association methods that have been developed for Aerospace applications can be applied to the traffic monitoring function of Advanced Traffic Management Systems (ATMS). It first discusses techniques that have been developed for background estimation and detection of vehicles on a roadway. Then, the transformation to tracking coordinates and the multiple target tracking (MTT) algorithm that produces traffic flow observation data are outlined. An extended Kalman filter that takes observed flow data from multiple sensor sites and produces flow estimates for an entire roadway is described and its application to incident detection discussed. Preliminary results using simulated and actual freeway data are presented. Finally, techniques for presenting this data to the user and the manner in which these signal and data processing techniques relate to an overall ATMS design are outlined.
Global area coverage (GAC) pixel data from the polar-orbiter advanced very high resolution radiometer (AVHRR) and the cloud classifications for 2 X 2 pixel arrays, output from CLAVR Phase-I, constitute the input for t...
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ISBN:
(纸本)0819411701
Global area coverage (GAC) pixel data from the polar-orbiter advanced very high resolution radiometer (AVHRR) and the cloud classifications for 2 X 2 pixel arrays, output from CLAVR Phase-I, constitute the input for the CLAVR Phase-II analysis. The total cloud amount product from Phase-I was based on the assignment of fractional amounts of 1.0 and 0.5 to every pixel labeled cloudy or mixed, respectively, but the latter assignment led to biased total cloud amounts near 50%. In Phase-II, radiometric cloud amounts are determined for the mixed pixels from 11 micrometer radiances within a mapped grid area. The Phase-II procedure was developed for the identification and stratification of overcast (OVCST) cloud types, according to the cloud classifications of Phase-I, in grid areas also containing subsets of mixed and clear pixels. All mixed pixels associated with an observed OVCST type are analyzed statistically to determine fractional amounts of each cloud type (layer) as well as the total cloud amount within the grid area. The bias of Phase-I estimates was eliminated.
An algorithm is presented for tracking a landing aircraft using two different passive sensors, a laser range finder and an infrared camera. The main feature of this algorithm is that it is able to identify and compens...
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ISBN:
(纸本)0819411922
An algorithm is presented for tracking a landing aircraft using two different passive sensors, a laser range finder and an infrared camera. The main feature of this algorithm is that it is able to identify and compensate for abrupt disturbances. The algorithm is based on the extended Kalman filter (EKF) and the filtering confidence function (FCF) which introduces a learning approach to the tracking problem. The results of simulation using this learning tracking algorithm and the extended Kalman filter alone are presented and compared.
The segmentation of hand and wrist radiographs for applications such as skeletal maturity assessment is best achieved by model-driven approaches incorporating anatomical knowledge. The reasons for this are discussed, ...
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ISBN:
(纸本)0819411388
The segmentation of hand and wrist radiographs for applications such as skeletal maturity assessment is best achieved by model-driven approaches incorporating anatomical knowledge. The reasons for this are discussed, and a particular frame-based or 'blackboard' strategy for the simultaneous segmentation of the hand and estimation of bone age via the TW2 method is described. The new approach is structured for optimum robustness and computational efficiency: features of interest are detected and analyzes in order of their size and prominence in the image, the largest and most distinctive being dealt with first, and the evidence generated by feature analysis is used to update a model of hand anatomy and hence guide later stages of the segmentation. Closed bone boundaries are formed by a hybrid technique combining knowledge-based, one-dimensional edge detection with model-assisted heuristic tree searching.
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