MARC 主機 00000nam  2200349   4500 
001    AAI1465264 
005    20100608091152.5 
008    100608s2009    ||||||||||||||||| ||eng d 
020    9781109182255 
035    (UMI)AAI1465264 
040    UMI|cUMI 
100 1  Osuna, Francisco 
245 10 Semi-automated frame transformations using FFT analysis on
       two-dimensional images 
300    69 p 
500    Source: Masters Abstracts International, Volume: 47-06, 
       page: 3653 
500    Adviser: Steven Roach 
502    Thesis (M.S.)--The University of Texas at El Paso, 2009 
520    Cassini entered Saturn's orbit on July 1, 2004 beginning a
       four-year exploration of Saturn. In 2008 the mission was 
       extended, and Cassini continues to collect and transmit 
       images and data collected during its mission. In order to 
       accurately interpret images, it is necessary to know the 
       location and orientation of the camera provided the field 
       of view when the image was collected. While the mission 
       managers provide initial estimates of this orientation, 
       scientific analysis requires better estimates than the 
       initial data provided. Navigation is a process for 
       improving the estimation of the true camera pointing 
       vector as determined by features identified in an image. 
       Features such as the body of Saturn or specific rings can 
       be utilized to approximate the correct position and 
       orientation of Cassini 
520    The Cassini Viewing Utility (CASVU) is a set of tools 
       developed by the Software Engineering Research Group at 
       the University of Texas at El Paso designed to facilitate 
       the analysis of data returned by Cassini. In particular, 
       the Navigation tool is provided for the correction of 
       orientation and positioning of Cassini. CASVU uses the 
       perspective projection approach to model a 3-D environment
       as seen from Cassini. The 3-D model is composed of 
       wireframes that provide a predict view of Saturn and the 
       rings assuming the initial estimation of camera 
       orientation. These wireframes are superimposed on an image
       collected by Cassini. Features in the images are 
       identified, and a Fast Fourier Transform based algorithm 
       computes rotation and shift ratios between the predict 
       wireframe and image. These ratios can then be applied to 
       the predict wireframe to correct the pointing vector of 
520    This thesis presents a semi-automated FFT-based navigation
       algorithm that can be utilized for the correction of 
       spacecraft pointing estimates when integrated into CASVU 
590    School code: 0459 
650  4 Engineering, Aerospace 
690    0538 
710 2  The University of Texas at El Paso.|bComputer Science 
773 0  |tMasters Abstracts International|g47-06 
856 40 |u