Engineering topics

Lorre, Jean J.

Publications and source records attributed to Lorre, Jean J..

8 records

NASA NTRS2012

In Situ Mosaic Brightness Correction

In situ missions typically have pointable, mast-mounted cameras, which are capable of taking panoramic mosaics comprised of many individual frames. These frames are mosaicked together. While the mosaic software applies radiometric correction to the images, in many cases brightness/contrast seams still exist between frames. This is largely due to errors in the radiometric correction, and the absence of correction for photometric effects in the mosaic processing chain. The software analyzes the overlaps between adjacent frames in the mosaic and determines correction factors for each image in an attempt to reduce or eliminate these brightness seams.

Deen, Robert G.↗

NASA NTRS2010

In-Situ Pointing Correction and Rover Microlocalization

Two software programs, marstie and marsnav, work together to generate pointing corrections and rover micro-localization for in-situ images. The programs are based on the PIG (Planetary Image Geometry) library, which handles all mission dependencies. As a result, there is no mission-specific code in either of these programs. This software corrects geometric seams in images as much as possible.

Deen, Robert G.↗

NASA NTRS2002

Analysis of Mars Orbiter Camera Stereo Pairs

We have developed stereo image processing procedure for the Mars Orbiter Camera based on VICAR software package. We will present topography and shaded relief maps, extracted from both Wide and Narrow Angle stereo image pairs. Additional information is contained in the original extended abstract.

Ivanov, Anton B.↗

NASA NTRS1997

Registration assisted mosaic generation

This paper presents a general strategy for assembling mosaics from numerous individual images where uncertainty exists in the position and orientation of those images. Both of the presented applications relate to remotely operated camera platforms, the first being the Galileo solid state imaging (SSI) camera presently in orbit around Jupiter, and the second being the Imager for Mars Pathfinder (IMP) stereo camera on Mars. A basic strategy in both applications is to determine the correct relative camera pointing followed by direct map projection of the images. It is assumed that approximate camera pointing exists sufficient to locate adjacent images and to place initial tiepoints within reach of the correlator. Spatial correlation is used to fix tiepoints whose initial locations are predicted by the camera pointing. We use either an fast fourier transform (fft) algorithm or a variant of Gruen's scheme permitting limited image rotation and skew. The Gruen correlator has three hierarchical modes: 1) A classical spatial least squares correlation on integral pixel boundaries used when rotation is small. 2) An annealing non-deterministic search used when rotations are unknown. A simplex deterministic search used for the end game. The correlation operation can be performed either interactively or autonomously. The final camera pointing solution relies upon a simplex downhill search in 2n or 3n dimensions where n is the number of images comprising the mosaic and the objective function to be minimized is the disagreement between tiepoint locations predicted from the camera pointing with those observed by the correlator. For Galileo the 3n unknowns are euler angles defining camera pointing in planet coordinates, and for Mars Pathfinder they are 2n unknowns representing commanded azimuth and elevation in the Lander coordinate system.

Lorre, Jean J.↗

NASA NTRS1995

Synthesis Of Realistic Animations Of A Person Speaking

Actors computer program implements automated process that synthesizes realistic animations of person speaking. Produces "newscaster" type video sequences. Uses images of person and, therefore, not limited to cartoons and cartoonlike movies. Potential applications also include use of process for automatically producing on-the-fly animations for human/computer interfaces and for reducing bandwidth needed to transmit video telephone signals.

Scott, Kenneth C.↗

NASA NTRS1991

Video Image Communication And Retrieval - Updated

Video Image Communication and Retrieval (VICAR) package of computer programs is general-purpose image-processing software system. Intended for processing data from Jet Propulsion Laboratory's unmanned planetary spacecraft, now used in variety of other applications, including processing of biomedical images, cartography, studies of Earth resources, and geological exploration. Development of newest version of VICAR emphasizes standardized, easily-understood user interface, shield between user and host operating system, and comprehensive array of image-processing capabilities.

Wall, Ray J.↗

NASA NTRS1988

Image processing in optical astronomy

Successful efforts to enhance optical-astronomy images through digital processing often exploit such 'weaknesses' of the image as the objects' near-symmetry, their preferred directionality, or a differentiation in spatial frequency between the object or objects and superimposed clutter. Attention is presently given to the calibration of a camera prior to astronomical data-acquisition, methods for the enhancement of faint surface brightness features, automated target detection and extraction techniques, the importance of the geometric transformations of digital imagery, the preparation of two-dimensional histograms, and the application of polarization.

Lorre, Jean J.↗

NASA NTRS1988

Function minimization with partially correct data via simulated annealing

The simulated annealing technique has been applied successfully to the problem of estimating the coefficients of a function in cases where only a portion of the data being fitted to the function is truly representative of the function, the rest being erroneous. Two examples are given, one in photometric function fitting and the other in pattern recognition. A schematic of the algorithm is provided.

Lorre, Jean J.↗