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| * Review [[LIMVECS.TXT]] to ensure they are stable. | * Review [[LIMBVECS.TXT]] to ensure they are stable. |
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| * Merge with existing shape model. Not required -- you can just use [[LIMBVEC.TXT]] by itself, but you are more likely to get spikes at the beginning of the model. * {{cat SHAPEFILES.TXT LIMBVEC.TXT > new-shape.txt}} |
* Merge with existing shape model. Not required -- you can just use [[LIMBVECS.TXT]] by itself, but you are more likely to get spikes at the beginning of the model. * {{cat SHAPEFILES.TXT LIMBVECS.TXT > new-shape.txt}} |
Describe limber here.
Limber is used to create LIMBVECS.TXT, which is a list of limb intersections for each image in body fixed coordinates.
These vectors can be used to create a shape model or merged with an existing model.
Input
Limber uses the file LIMBER.IN to set parameters.
Output
It creates LIMBVECS.TXT
Usage notes
Procedures
Get a starting shape model. You can use triax to build an ICQ for a starting shape model. You only need a Q of about 8 to get started. You can use the distance to target to get a 1st order estimate of the image pixel scale. With that, you can review the first images and measure the a, b and c axis of the object. These you feed into triax to get a starting shape model. It is trivial to estimate the rotation period from the images if you have a rotation movie.
- Register the images. Make sure that the center of figure of the model and the images are aligned.
Get a pole. Use either register with the x option or some other tool to get the RA and Dec for the pole (external source). Right now, I am estimating that the solution needs to be within 10 degrees of the correct value for limber to function well.
- *Limber Loop* - Perform the following until the shape model is within 2 pixels of the images
Run limber to get LIMBVECS.TXT
Review LIMBVECS.TXT to ensure they are stable.
You can use gnuplot (deleting the first line) or vecs2shape then shape2maps then view_map
Review the coverage of limbs coverage. You expect to see a reasonable field of white points denoting that the images are generating good limbs. Gaps are okay because concave objects lack portions that display limbs.
Merge with existing shape model. Not required -- you can just use LIMBVECS.TXT by itself, but you are more likely to get spikes at the beginning of the model.
- Remove the two Q values and the "END"
Convert a point cloud (list of vectors) into a shape model ICQ
vecs2shape This builds a shape from the vectors using spherical harmonics, so it has smooth edges
vecs2cube The builds a shape using only vectors. It is more accurate, but more likely to have artifacts (spikes). If this method is used, it may be good to dumb that new model down and run it through vecs2shape to generate a more stable model.
Review the model using shape2maps then view_map - or the viewMaps.sh if available.
- Install the model. Copy or symbolically relink it
relink.sh step1-icq.txt SHAPE.TXT
- Register the images to the new shape model
- Evaluate the registration
evalReg PICTLIST.TXT
- Repeat until the model is good. Good is defined as the agreement between the cyan and magenta shapes are within 2 pixels. At some point, you can stop merging the old shape model