This program will import raw images, acquired from the Near Earth Asteroid
Rendezvous - Shoemaker (NEAR Shoemaker) mission's Multispectral Imager
(MSI) instrument, to ISIS data file format.
The raw image must be in FITS (Flexible Image Transport) format and
have a PDS label file that points to the location of the FITS image. You
must input either the label file or the FITS file for the "TO" input
parameter. Projected images are not supported. Please note if the FITS
file is given, the label file must exist in the same directory or the
program will throw an error.
This program will verify that the input files are valid by checking the
following label keyword values. An error will be thrown if any of these
criteria are not met.
INSTRUMENT_ID = MSI
LINE_SAMPLES = 537
LINES = 244
SAMPLE_DISPLAY_DIRECTION = RIGHT
LINE_DISPLAY_DIRECTION = UP
The output cube- successfully imported into ISIS goes through the following
processes:
Convert the raw FITS image data to an ISIS cube.
Save the labels from the input PDS label file to the output
ISIS cube. Note that FITS labels are not transferred.
Enlarge the image from 537 samples x 244 lines to 537 x 412 using the
user-specified interpolation algorithm. Defaults to cubic
convolution.
Flip the image vertically, i.e. across the horizontal axis.
Trim 33 pixels from the top, bottom, left and right sides. These
pixels along the borders will be set to nulls.
Image Trimming
Shortly after orbit insertion around Eros, the NEAR spacecraft
experienced a failed burn that contaminated the MSI instrument with
hydrazine. The NEAR/MSI team developed a preliminary remediation [1] of
the blur effect of the contamination using FFTs to correct the point
spread function (PSF). A residual side effect of this correction was
degradation of ~33 pixels on all edges of the images. As a result, by
default, NEAR/MSI images are trimmed 33 pixels around all edges after
import. MSI images requiring trmming of these data are of the form
m0132069107f4_2p_iof_dbl.img.
Additional remediation work of the PSF function used to correct MSI
images was performed by Golish [2] that resulted in an enhanced PDF
correction that did not introduce edge-artifacts as was seen in [1].
The TRIM parameter was added to optionally retain the 33 pixels around
the image edges when the dataset from [2] is used. File names that do
not require trimming are of the form m0132069107f4_2p_iof_gbl.img (note
the gbl).
Note the images produced by Golish [2] have already been expanded. So
msi2isis was altered to check for the expanded size (in lines only) to
allow for the full frame to be ingested. In this case, the intermediate
step to interpolate in the line dimension to expand the the number of
lines from 244 to 412 is not needed and excluded from ingestion
processing. All other (label) checks were left to complete the
validation of the input files.
Updated to add labels from the input PDS label file to the output ISIS
cube. References #2088.
Kris Becker
2019-08-15
Correct SpacecraftClockStartCount/SpacecraftClockStopCount values to be
compatible with NAIF SCLK kernels that enables use in the camera model.
Save original values in new keywords prepended with "Original".
Kris Becker
2021-02-19
Added the TRIM parameter to optionally trim data around the edges of
some MSI images due to degradation resulting from remediation of the
PSF.
Name of the input NEAR MSI image file to be imported into ISIS
format. You may enter the label or the image file. If the image
file is given, the program will search in the same directory for a
label file with the same base name as the image file base name.
This parameter is provided to turn off trimming 33 pixels from the
edge of images. When TRIM=TRUE, 33 pixels on all sides of the
expanded image are set to NULL but not removed. The source of this
degradation is image edge-effects created from the remediation of
hydrazine contamination of the MSI filters. If TRIM=FALSE, no pixels
around the edge of the images are NULLed. This is useful to retain
image edges that originate from several alternative archive sources
[2].
