PDS_VERSION_ID       = PDS3                                                   
LABEL_REVISION_NOTE          = "2003-09-30 Cornell:carcich"                   
RECORD_TYPE          = STREAM                                                 
OBJECT               = TEXT                                                   
  PUBLICATION_DATE   = 2003-09-30                                             
  NOTE               = "                                                      
    MSKINT12_README.TXT file for CONTOUR Archive Volume                       
"                                                                             
END_OBJECT                                                                    
END                                                                           
                                                                              
####### File _MSKINT12_README.TXT_                                            
                                                                              
    Mask-Based Image Interpolation Package for IDL                            
                                                                              
    Design, supervision, contact:                                             
        Dr. Joseph Harrington                                                 
        326 Space Sciences Building                                           
        Cornell University                                                    
        Ithaca, NY 14853-6801                                                 
        jh@oobleck.astro.cornell.edu                                          
                                                                              
    Programmers:                                                              
        Siree Vatanavigkit (Cornell)    Version 1.0     3 Aug 99              
            initial implementation                                            
        Alex Ruane (Cornell)        Version 1.1    20 Nov 00                  
            second order surface fit                                          
            chebyshfit bug fixes                                              
            general bug fixes                                                 
                                                                              
    Bug fixes and performance enhancements:                                   
        Wayne Landsman (NASA/GSFC)    Version 1.2    29 Oct 01                
            removal of loops                                                  
                                                                              
EXPLANATION:                                                                  
    Given an image data array (2D) and a mask (of the same size)              
    which identifies bad pixels in the image with a 0 and                     
    good pixels with a 1, use function maskinterp to correct the              
        the bad pixels.  The user can select from six interpolating           
    functions for maskinterp to use as a model for fitting data.              
    Maskinterp interpolates only from surrounding good pixels,                
    but ensures that there are enough pixels for a good fit and               
    that their distribution is not spatially biased.  User                    
    instructions appear in the header comment of each function.               
    Examples are in testinterp.pro.                                           
                                                                              
    The interpolating functions are described below.                          
                                                                              
    plsfit.pro    plane surface fit:                                          
    z = ax +by +c                                                             
                                                                              
    gausfit.pro    gaussain surface fit:                                      
    z = (1/(2*pi*thx*thy))*exp(-.5*(((x-mx)/thx)^2+((y-my)/thy)^2 ))-c        
                                                                              
    chebyshfit.pro    Chebyshev polynomial interpolation:                     
    z = sum(Ti*Ci)  + .5*C0                                                   
                                                                              
    csplinterp.pro    bicubic spline interpolation                            
                                                                              
    splinterp.pro   bicubic spline interpolation                              
                                                                              
            csplinterp and splinterp differ by the                            
            functions used to calculate spline. More                          
            details are in the header of each function.                       
                                                                              
    twoordfit.pro   second-order polynomial surface interpolation             
    z = ax^2 + bxy + cy^2 + dx + ey + f                                       
                                                                              
TEST:                                                                         
    Run IDL from the directory that jup.fits and mask.fits reside in.         
    Run testinterp.pro.  These steps should produce six .fits files.          
    If all the codes run correctly, the difference in these files             
    should be less than the tolerance of the average error per pixel          
    (default to 1e-7).                                                        
    Given the following .fits files:                                          
    testcsplinterp0.fits                                                      
    testsplinterp0.fits                                                       
        testginterp0.fits                                                     
    testchebyinterp0.fits                                                     
    testplinterp0.fits                                                        
    testtwoordinterp0.fits                                                    
    Run the following commands.  It may take a few minutes to run             
    the codes.                                                                
    idl                                                                       
    testinterp                                                                
    exit                                                                      
    Expected results:                                                         
    If the average error per pixel is close to the the precision              
    of your machine, the screen should display the following lines.           
    testplinterp.fits:good                                                    
    testginterp.fits:good                                                     
    testcsplinterp.fits:good                                                  
    testsplinterp.fits:good                                                   
    testchebyinterp.fits:good                                                 
    testtwoordinterp.fits:good                                                
    Otherwise, the name of the file(s) and its average error per pixel is     
    displayed.  User may specify the tolerance of the average error           
    per pixel by calling testinterp, eps = tolerance, for example             
    testinterp, eps = 1e-30.                                                  
                                                                              
IDL FUNCTIONS:                                                                
    maskinterp.pro                                                            
    plsfit.pro                                                                
    gausfit.pro                                                               
    csplinterp.pro                                                            
    splinterp.pro                                                             
    chebyshfit.pro                                                            
    twoordfit.pro                                                             
    disc.pro                                                                  
    coord.pro                                                                 
    keyword_defined.pro                                                       
    testinterp.pro                                                            
    filecomp.pro                                                              
    chvarchg.pro                                                              
EXAMPLE/TEST DATA:                                                            
    jup.fits                                                                  
    mask.fits                                                                 
    testcsplinterp0.fits                                                      
    testsplinterp0.fits                                                       
        testginterp0.fits                                                     
    testchebyinterp0.fits                                                     
    testplinterp0.fits                                                        
    testtwoordinterp0.fits