Spatial Registration of A Lunar Orbiter Frame/Subframe to the

Clementine 750-nm Geodetically Controlled Base Map using ISIS

(Manual or Rubber-Sheet Method)

As part of a pilot project to produce a digital archive of Lunar Orbiter
film data, the USGS has developed techniques to coregister mosaicked LO
frames (for medium-resolution data) and/or subframes (for
high-resolution LO data) to the Clementine 750-nm controlled base map.
These procedures require the use of ISIS freeware (including the IDL
interactive display routines; see
<http://wwwflag.wr.usgs.gov/isis-bin.cgi>) and are intended to follow
the digitization of LO film strips, mosaic construction, and geometric
rectification of the frames/subframes. The first routine, cosmetic
enhancement of the mosaicked frame/subframe via destriping, is optional.

-   Cosmetic enhancement of LO frame/subframe: Horizontal or "venetian
    blind" stripes are the primary image artifact in the LO data. These
    can be removed in ISIS via iterative spatial filtering or
    "destriping" without removing valid image data. Stripe dimensions
    below are for a horizontally oriented sub-frame mosaic (high
    resolution LO film-strip data scanned at 25-microns/pixel) with a
    vertical stripe pattern.

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-   Run the Perl script '*lodstr.pl*' to execute the following steps in
    ISIS:

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-   Convert mosaic from 8-bit to 16-bit to avoid saturation at filtering

> *dsk2dsk from=lunorb.cub to=16bit.cub otype=2*

-   Destripe procedure -- called repeatedly with varying stripe widths.

> *dstripe from=16bit to=d1 line1=301 samp1=1 line2=1 samp2=3*
>
> *dstripe from=d1 to=d2 line1=701 samp1=1 line2=1 samp2=15*
>
> *dstripe from=d2 to=d3 line1=701 samp1=1 line2=1 samp2=25*
>
> *dstripe from=d3 to=d4 line1=701 samp1=1 line2=1 samp2=51*
>
> *dstripe from=d4 to=d5 line1=9051 samp1=1 line2=1 samp2=151*
>
> *dstripe from=d5 to=d6 line1=15051 samp1=1 line2=1 samp2=901*
>
> *dstripe from=d6 to=lod line1=15051 samp1=1 line2=1 samp2=2703*

-   Rotate the destriped LO mosaic 270 degrees clockwise to approximate
    the position of the Clementine 750-nm base

> *random from=lod opt=rot rot=270.0*
>
> *geom from=lod to=lod_rot.cub*

-   Convert mosaic back to 8 bit

> *dsk2dsk from=lod_rot.cub to=lodcl otype=1 orange=(0,255)*

-   Retrieve Clementine 750nm base map

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-   Determine which Clementine 750-nm base tiles are needed based on the
    approximate latitude and longitude range of the Lunar Orbiter
    frame/subframe mosaic. Use the geodetically controlled 750-nm base
    map because it has more complete coverage than the multiband global
    mosaic. (Gaps in coverage exist in the multiband mosaic because
    extremely oblique and highly compressed images were eliminated
    during processing.)

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-   To build the Clementine subscene, the Web-based Mapmaker software is
    recommended
    (http://pdsimage.wr.usgs.gov/PDS/public/NavHelp/aboutmm.htm). This
    will allow the user to specify a geographic range, and will produce
    and deliver (via ftp) a 750-nm or multiband image mosaic.

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-   Reproject the Clementine map to the Orthographic projection,
    specifying the approximate latitude/longitude range and the center
    latitude and center longitude of the destriped & rotated mosaic.
    Retain the Clementine map resolution of 0.1 km/pixel.

> *nuproj from=clem750.cub /lat/lon/clat/clon/proj=orth/km=0.1*
>
> *geom from=clem750.cub to=clemorth.cub*

-   Resample the LO mosaic to reduce the spatial resolution to match the
    Clementine map resolution

> *magcube from=lodcl to=lod1km lscale=0.16667 sscale=0.16667*

-   Manually select and save match points between the Clementine 750 map
    and the LO mosaic. Approximately 200 measurements should be
    selected, and they should be distributed evenly and broadly
    throughout the mosaic. This requires use of the IDL interactive
    display routine "qmatch".

> *qmatch_large* (build and start-up .mat file and .pic file)

-   Convert .mat file to a control-point file format for rubber-sheeting
    with "warp2"

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-   Run the Perl script *mat2warp.pl* to perform warping or "rubber
    sheeting" of the LO mosaic. \* refers to Clementine base image
    dimensions.

> *warp2 from=lod1km cfile=cfile.dat ns= \* nl=\**
>
> *geom from=lod1km to=lod.warp.cub*

-   The accuracy of registration between the Clementine and LO files can
    be visually checked using *qview* to display and "blink" between the
    warped LO mosaic and the Clementine base map.

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-   If color overlays (e.g., using rgb or color-ratio views) are
    desired, the multiband Clementine data can be retrieved and
    reprojected as above. To create color-ratio Clementine cubes:

> *ratio from=lod.warp.cub sfrom=::2 from2=lod.warp.cub sfrom2=::1 +*
>
> *to=lod.warp.750_r_415.cub*
>
> *ratio from=lod.warp.cub sfrom=::2 from2=lod.warp.cub sfrom2=::4 +*
>
> *to=lod.warp.750_r_950.cub*
>
> *ratio from=lod.warp.cub sfrom=::1 from2=lod.warp.cub sfrom2=::2*
>
> *to=lod.warp.415_r_750.cub*
>
> *cubeit from=( lod.warp.750_r_415.cub, lod.warp.750_r_950.cub, +*
>
> *lod.warp.415_r_750.cub) to=lod.warp.colorratio.cub*

-   For viewing these coregistered files in color, the user must employ
    a program (such as PhotoShop) that allows transparent layering.
    Several ISIS programs allow the user to create standard image file
    formats from ISIS cubes: *isis2tiff* will create a black-and-white
    tiff file from the warped LO mosaic; the IDL display routine
    *isis2std* will create either a single-band black-and-white output
    file or a color output file in either jpeg or tiff formats from a
    multiband ISIS cube. These can be exported to a user-platform such
    as a PC or a Mac with PhotoShop, and imported as separate layers in
    a single file. The black-and-white LO mosaic should be used as the
    Background image, and the color image can be stretched and/or
    displayed as a semi-transparent overlay layer.

Contacts: Tammy Becker (<tbecker@usgs.gov>) or Lisa Gaddis
(<lgaddis@usgs.gov>)

Date: 5/18/01