Engineering topics
Jepsen, P. L.
Publications and source records attributed to Jepsen, P. L..
The Mars Express/NASA Project at JPL
The Mars Express/NASA Project supports ESA's Mars Express Mission by providing portions of MARSIS, and via US Co-Investigators, software, and studies. The Discovery Program supports developments for ASPERA. Additional information is contained in the original extended abstract.
U.S. Participation in the Mars Express Mission
NASA will provide the antenna and RF subsystem to the MARSIS radar sounder. There are 11 U.S. Co-Investigators for the science investigations, and navigation and data archiving support are also provided. ASPERA-3 receives NASA Discovery Program funding. Additional information is contained in the original extended abstract.
Image processing and analysis of Saturn's rings
Processing of Voyager image data of Saturn's rings at JPL's Image Processing Laboratory is described. A software system to navigate the flight images, facilitate feature tracking, and to project the rings has been developed. This system has been used to make measurements of ring radii and to measure the velocities of the spoke features in the B-Ring. A projected ring movie to study the development of these spoke features has been generated. Finally, processing to facilitate comparison of the photometric properties of Saturn's rings at various phase angles is described.
Voyager image processing at the Image Processing Laboratory
This paper discusses new digital processing techniques as applied to the Voyager Imaging Subsystem and devised to explore atmospheric dynamics, spectral variations, and the morphology of Jupiter, Saturn and their satellites. Radiometric and geometric decalibration processes, the modulation transfer function, and processes to determine and remove photometric properties of the atmosphere and surface of Jupiter and its satellites are examined. It is exhibited that selected images can be processed into 'approach at constant longitude' time lapse movies which are useful in observing atmospheric changes of Jupiter. Photographs are included to illustrate various image processing techniques.
Analysis of multiple imagery at Jet Propulsion Laboratory's Image Processing Laboratory
During the past decade advanced techniques have been developed at JPL for processing large volumes of imagery returned by the more recent planetary spacecraft. In addition, the Image Processing Laboratory has become involved in the processing of earth resources imagery acquired by Landsat and a variety of other sensors flown on aircraft and spacecraft. The trend within the facility has been toward the development of technology capable of processing increasingly larger image data bases. A variety of applications in both the planetary and earth observations areas involve the merging and/or processing of more than one image and often require the correlation of data acquired by a variety of sensors.
Dynamic feature analysis for Voyager at the Image Processing Laboratory
Voyager 1 and 2 were launched from Cape Kennedy to Jupiter, Saturn, and beyond on September 5, 1977 and August 20, 1977. The role of the Image Processing Laboratory is to provide the Voyager Imaging Team with the necessary support to identify atmospheric features (tiepoints) for Jupiter and Saturn data, and to analyze and display them in a suitable form. This support includes the software needed to acquire and store tiepoints, the hardware needed to interactively display images and tiepoints, and the general image processing environment necessary for decalibration and enhancement of the input images. The objective is an understanding of global circulation in the atmospheres of Jupiter and Saturn. Attention is given to the Voyager imaging subsystem, the Voyager imaging science objectives, hardware, software, display monitors, a dynamic feature study, decalibration, navigation, and data base.
Removal of instrument signature from Mariner 9 television images of Mars
The Mariner 9 spacecraft was inserted into orbit around Mars in November 1971. The two vidicon camera systems returned over 7300 digital images during orbital operations. The high volume of returned data and the scientific objectives of the Television Experiment made development of automated digital techniques for the removal of camera system-induced distortions from each returned image necessary. This paper describes the algorithms used to remove geometric and photometric distortions from the returned imagery. Enhancement processing of the final photographic products is also described.
A user's guide to the Mariner 9 television reduced data record
The Mariner 9 television experiment used two cameras to photograph Mars from an orbiting spacecraft. For quantitative analysis of the image data transmitted to earth, the pictures were processed by digital computer to remove camera-induced distortions. The removal process was performed by the JPL Image Processing Laboratory (IPL) using calibration data measured during prelaunch testing of the cameras. The Reduced Data Record (RDR) is the set of data which results from the distortion-removal, or decalibration, process. The principal elements of the RDR are numerical data on magnetic tape and photographic data. Numerical data are the result of correcting for geometric and photometric distortions and residual-image effects. Photographic data are reproduced on negative and positive transparency films, strip contact and enlargement prints, and microfiche positive transparency film. The photographic data consist of two versions of each TV frame created by applying two special enhancement processes to the numerical data.