TRIMMER

Description

TRIMMER is designed for a flyby situation where some parts of the body are never seen in any of the images. It uses the sumfiles for each image in an input list to identify what parts of the image are visible to the camera and which parts of the image are illuminated. TRIMMER determines where the shape model is visible and illuminated but, according to the images and their sumfiles, shouldn’t be (i.e., things that stick up too far). After identifying these areas, TRIMMER trims them down in the radial direction by a specified amount. It whittles down the shape until the areas of the shape model that are supposed to be in the dark are indeed in the dark. TRIMMER can also “pump” up areas of the shape that are too low, but Bob says that you can get in trouble using this feature and it has not been tested for DART.

TRIMMER does not affect maplets; it only affects the shape model. The trimmed shape model can then be dumbed down and used in densify, for example. However, TRIMMER distinguishes between areas of the shape covered by maplets vs. areas with no maplet coverage. TRIMMER relies on COVERAGE.TXT for maplet coverage, so you can fool TRIMMER into thinking that an area is not covered by maplets by changing the inputs to shape_coverage. In order to TRIMMER to fully operate on all parts of the shape, shape_coverage must find no maplets.

Input Files

*SHAPEFILES/COVERAGE.TXT. TRIMMER uses this file to determine where maplets exist. *TRIMMER.TXT. A text file that lists all images you want to use for TRIMMER. Usually, this is all registered images, but a more restricted approach would be to only use images that contain LMKs. The image names need to be preceded by a space. The last line is END (no leading space). *SHAPEFILES/SHAPEX.TXT. TRIMMER operates on SHAPEX.TXT. It does not affect SHAPE.TXT. Before starting TRIMMER, copy the shape you want to trim to SHAPEX.TXT. SHAPE1.TXT (Q = 128) is often a good shape to start with, especially early in the shape modeling process. The higher the Q value of the shape, the longer TRIMMER will take to run. If you have a very mature model that you are trying to polish, running on a higher-resolution model may be appropriate. *IMAGEFILES *SUMFILES

Output Files

*SHAPEFILES/ILLUM.TXT. Use as an input to shape2mapsA to show areas of the shape that are illuminated. *SHAPEFILES/VISIBLE.TXT Use as an input to shape2mapsA to show areas of the shape that are visible in the images. *SHAPEFILES/V_AND_I.TXT. Use as an input to shape2mapsA to show areas of the shape that are both visible and illuminated in the images. *SHAPEFILES/SHAPEX.TXT. The trimmed shape.

Using TRIMMER

  1. Verify that you have copied whatever shape model you wish to trim into SHAPEFILES/SHAPEX.TXT.

  2. Run shape_coverage using SHAPEFILES/SHAPEX.TXT as the input shape and the desired set of input parameters. See wiki page for shape_coverage. After running shape_coverage, do the following so that TRIMMER knows which areas are covered by maplets that meet the criteria used in shape_coverage. The most aggressive option is to run shape_coverage with inputs that result in no landmarks matching the parameters. TRIMMER would then operate freely across the entire shape, rather than holding back in areas with maplet coverage.