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Juday, Richard D.

Publications and source records attributed to Juday, Richard D..

At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

A hybrid six degree-of-freedom tracking system

An optical/digital/mechanical six degree of freedom tracking system using an optical correlator for image processing is being constructed at NASA's Johnson Space Center. The degrees of freedom are expressed in sensor coordinates as azimuth, elevation, range, line-of-sight rotation, and the two out-of-plane object rotation angles. Hardware for an initial configuration has been assembled and various tracking algorithms and filtering techniques are being implemented and evaluated. The current correlator hardware is based on LCTV SLMs from a commercial television projector. Correlation peak detection and measurement are made using commercially available digital image processing boards. Out-of-plane object rotation, range, and line-of-sight rotation are tracked by various correlation filter techniques. Performance of the current system is presented, as are plans for future configurations.

Monroe, Stanley E., Jr.↗
NASA NTRS1992

Autonomous planetary landing guidance by optical correlation

We describe our planned use of optical correlation in landmark navigation associated with planetary landing. Standard correlation provides 'pointing-to' information, giving the vector to the landmark from the spacecraft in the spacecraft frame. The synthetic estimation filter (SEF) provides 'pointing-from' information, estimating the vector from the landmark to the spacecraft. Digital and optical SEFs were constructed and compared using a Martian-like 3D modelboard to provide test images. The digital SEF worked reasonably well, but the optical SEF did not perform as expected. The optical SEF was implemented with a liquid crystal television (LCTV) correlator that had been used successfully in previous SEF experiments using a spacecraft model. The results suggest the SLM model for the LCTV needs further refinements. Both the digital and optical filter provided good pointing-to results. We did not plot the correlation surface for the digital SEF response, and though it is less sharp than the POF, it had only a one-pixel variation in the peak location. Surface plots for the conventional optical phase-only filter produced a correlation peak that was sharp enough to be located within two pixels.

Knopp, Jerome↗
NASA NTRS1992

Selection of LCTV operating curves for input and filter

A liquid crystal television (LCTV) SLM's phase, amplitude, and polarization all influence our selection of operating curves for input and filter. With its continuum of drive voltage, the LCTV permits grey-level control in both locations. Selection of an optimum curve depends on expected variations in signal amplitude, presence of input scene structured noise, and other factors. Using modulators obtained from a commercially available projection LCTV, and with no specifically added input noise present, we have obtained laboratory results in which the ratio of peak intensity to correlator system noise exceeded 100:1. Unfortunately, it was massively inefficient to implement the algorithm which had been developed as the abstract for this paper was submitted. Fortunately, we have quite recently developed two insights that will speed it by several orders of magnitude, and we shall report that result in the future. We will also extend the work to include clutter objects and additive input scene noise.

Juday, Richard D.↗
NASA NTRS1992

Visual information processing; Proceedings of the Meeting, Orlando, FL, Apr. 20-22, 1992

Topics discussed in these proceedings include nonlinear processing and communications; feature extraction and recognition; image gathering, interpolation, and restoration; image coding; and wavelet transform. Papers are presented on noise reduction for signals from nonlinear systems; driving nonlinear systems with chaotic signals; edge detection and image segmentation of space scenes using fractal analyses; a vision system for telerobotic operation; a fidelity analysis of image gathering, interpolation, and restoration; restoration of images degraded by motion; and information, entropy, and fidelity in visual communication. Attention is also given to image coding methods and their assessment, hybrid JPEG/recursive block coding of images, modified wavelets that accommodate causality, modified wavelet transform for unbiased frequency representation, and continuous wavelet transform of one-dimensional signals by Fourier filtering.

Huck, Friedrich O.↗
NASA NTRS1992

Human low vision image warping - Channel matching considerations

We are investigating the possibility that a video image may productively be warped prior to presentation to a low vision patient. This could form part of a prosthesis for certain field defects. We have done preliminary quantitative studies on some notions that may be valid in calculating the image warpings. We hope the results will help make best use of time to be spent with human subjects, by guiding the selection of parameters and their range to be investigated. We liken a warping optimization to opening the largest number of spatial channels between the pixels of an input imager and resolution cells in the visual system. Some important effects are not quantified that will require human evaluation, such as local 'squashing' of the image, taken as the ratio of eigenvalues of the Jacobian of the transformation. The results indicate that the method shows quantitative promise. These results have identified some geometric transformations to evaluate further with human subjects.

Juday, Richard D.↗
NASA NTRS1991

Programmable remapper for image processing

A video-rate coordinate remapper includes a memory for storing a plurality of transformations on look-up tables for remapping input images from one coordinate system to another. Such transformations are operator selectable. The remapper includes a collective processor by which certain input pixels of an input image are transformed to a portion of the output image in a many-to-one relationship. The remapper includes an interpolative processor by which the remaining input pixels of the input image are transformed to another portion of the output image in a one-to-many relationship. The invention includes certain specific transforms for creating output images useful for certain defects of visually impaired people. The invention also includes means for shifting input pixels and means for scrolling the output matrix.

Juday, Richard D.↗
NASA NTRS1991

Compensating For Movement Of Eye In Laser Surgery

Conceptual system for laser surgery of retina includes subsystem that tracks position of retina. Tracking signal used to control galvanometer-driven mirrors keeping laser aimed at desired spot on retina as eye moves. Alternatively or additionally, indication of position used to prevent firing of laser when eye moved too far from proper aiming position.

Juday, Richard D.↗
NASA NTRS1991

Three dimensional moire pattern alignment

An apparatus is disclosed for determining three dimensional positioning relative to a predetermined point utilizing moire interference patterns such that the patterns are complementary when viewed on axis from the predetermined distance. Further, the invention includes means for determining rotational positioning in addition to three dimensional translational positioning.

Juday, Richard D.↗
NASA NTRS1991

Optical joint correlator for real-time image tracking and retinal surgery

A method for tracking an object in a sequence of images is described. Such sequence of images may, for example, be a sequence of television frames. The object in the current frame is correlated with the object in the previous frame to obtain the relative location of the object in the two frames. An optical joint transform correlator apparatus is provided to carry out the process. Such joint transform correlator apparatus forms the basis for laser eye surgical apparatus where an image of the fundus of an eyeball is stabilized and forms the basis for the correlator apparatus to track the position of the eyeball caused by involuntary movement. With knowledge of the eyeball position, a surgical laser can be precisely pointed toward a position on the retina.

Juday, Richard D.↗
NASA NTRS1991

Three-Dimensional Moire Pattern

Use of moire patterns to determine positions extended to three dimensions. Concept requires two moire templates or grids, separated from each other. Template on side closer to observer contains alternating black and transparent areas. Template farther from observer contains alternating black and white areas. Observer determines position of center of perspective, also receiving indication of depth even without stereoscopic view. Used in rangefinding applications in which precision not required. Also used to gauge location of mobile robot in environment hostile to humans.

Juday, Richard D.↗
NASA NTRS1991

Optimal real correlation filters

Expressions are derived for real filters that have a maximum correlation signal to noise ratio. Both continuous and discrete cases are treated and shown to have similar forms. The signal can be complex, and the case of a real signal is considered and related to previous results.

Juday, Richard D.↗
NASA NTRS1991

Optical correlators for automated rendezvous and capture

The paper begins with a description of optical correlation. In this process, the propagation physics of coherent light is used to process images and extract information. The processed image is operated on as an area, rather than as a collection of points. An essentially instantaneous convolution is performed on that image to provide the sensory data. In this process, an image is sensed and encoded onto a coherent wavefront, and the propagation is arranged to create a bright spot of the image to match a model of the desired object. The brightness of the spot provides an indication of the degree of resemblance of the viewed image to the mode, and the location of the bright spot provides pointing information. The process can be utilized for AR&C to achieve the capability to identify objects among known reference types, estimate the object's location and orientation, and interact with the control system. System characteristics (speed, robustness, accuracy, small form factors) are adequate to meet most requirements. The correlator exploits the fact that Bosons and Fermions pass through each other. Since the image source is input as an electronic data set, conventional imagers can be used. In systems where the image is input directly, the correlating element must be at the sensing location.

Juday, Richard D.↗
NASA NTRS1991

Full complex spatial filtering with a phase mostly DMD

A new technique for implementing fully complex spatial filters with a phase mostly deformable mirror device (DMD) light modulator is described. The technique combines two or more phase-modulating flexure-beam mirror elements into a single macro-pixel. By manipulating the relative phases of the individual sub-pixels within the macro-pixel, the amplitude and the phase can be independently set for this filtering element. The combination of DMD sub-pixels into a macro-pixel is accomplished by adjusting the optical system resolution, thereby trading off system space bandwidth product for increased filtering flexibility. Volume in the larger dimensioned space, space bandwidth-complex axes count, is conserved. Experimental results are presented mapping out the coupled amplitude and phase characteristics of the individual flexure-beam DMD elements and demonstrating the independent control of amplitude and phase in a combined macro-pixel. This technique is generally applicable for implementation with any type of phase modulating light modulator.

Florence, James M.↗
NASA NTRS1991

Full complex modulation with two one-parameter SLMs

Although the action of a spatial light modulator (SLM) is usually restricted to certain locations on the operating curve of the complex plane, NASA is planning to use architectures that allow two continuously variable SLMs to function jointly so as to access the full interior of a closed curve in the complex plane. This paper describes three fundamental methods for attaining full complex modulation. The mathematics for two of these methods is presented, and signal decomposition in their terms is outlined.

Juday, Richard D.↗
NASA NTRS1990

Data association multiple target tracking using a phase-mostly liquid crystal television

This paper presents a technique of using data association target tracking in a motion sequence via an adaptive joint transform correlator. The massive data in the field of view can be reduced to a few correlation peaks. The average velocity of a target during the tracking cycle is then determined from the location of the correlation peak. A data association algorithm is used for the analysis of these correlation signals, with which multiple targets can be tracked. A phase-mostly liquid-crystal TV is used in the hybrid joint transform correlation system, and simultaneous tracking of three targets is demonstrated.

Tam, Eddy C.↗
NASA NTRS1990

Programmable Remapper

Input image remapped rapidly and accurately onto different coordinate grid. Analog/digital electronic image-processing system developed to warp input images onto arbitrary coordinate grids at video rates. Advantages of system include antialiasing effect of many-to-one data path and speed of lookup-table operation. Lookup tables reprogrammed easily with help of computer that generates table values from mathematical description of desired transformation. Applications include real-time corrections of distortions in input optics of image sensors, corrections for repeatable nonlinear scanning, and aiding persons of impaired vision by deliberately distorting images onto remaining functional portions of retinas.

Juday, Richard D.↗
NASA NTRS1990

Hybrid vision activities at NASA Johnson Space Center

NASA's Johnson Space Center in Houston, Texas, is active in several aspects of hybrid image processing. (The term hybrid image processing refers to a system that combines digital and photonic processing). The major thrusts are autonomous space operations such as planetary landing, servicing, and rendezvous and docking. By processing images in non-Cartesian geometries to achieve shift invariance to canonical distortions, researchers use certain aspects of the human visual system for machine vision. That technology flow is bidirectional; researchers are investigating the possible utility of video-rate coordinate transformations for human low-vision patients. Man-in-the-loop teleoperations are also supported by the use of video-rate image-coordinate transformations, as researchers plan to use bandwidth compression tailored to the varying spatial acuity of the human operator. Technological elements being developed in the program include upgraded spatial light modulators, real-time coordinate transformations in video imagery, synthetic filters that robustly allow estimation of object pose parameters, convolutionally blurred filters that have continuously selectable invariance to such image changes as magnification and rotation, and optimization of optical correlation done with spatial light modulators that have limited range and couple both phase and amplitude in their response.

Juday, Richard D.↗