Annotation file names are automatically created by the viewer when a save command is given. The syntax for annotation filenames are:
<image-file-name>.<index>.bm <image-file-name.<index>.bbWhere <image-file-name> is the root name of the image file and <index> is a unique integer number. The index number starts at 1 for the first annotation and is subsequently incremented for each additional annotation. Annotations are stored in the same directory as the image file. (For the web system read-only image databases, annotations are saved in the xbase location for that case).
Within a .bb boundary file each boundary is represented as an ordered vector of (x,y,z) location identifying triples of boundary coordinates. A closed boundary is indicated by the last coordinate being the same as the same as the first. Coordinates are stored in the Cartesian indexing scheme (the low value for y is at the bottom of the image).
The contents of the file horse.1.bb may be examined with the vpr command.
$ vpr horse.1.bb -h
[Bounding Box ]: [6]
0 512 0 512 0 0
[3-D vector ]: [15]
142 423.5 1 310 481.5 1
314 382.5 1 235 365.5 1
142 423.5 1
[3-D vector ]: [9]
276 132.5 1 329 150.5 1
276 132.5 1
Two 3D vectors are shown, the first contains the 4-coordinate boundary and the second corresponds to the line (actually a closed double line). The Mark tool can only create closed boundaries: the standard viewer is currently more flexible and can create points, lines, open vectors, and closed boundaries.
A "line" may created with the Mark tool by double clicking a second point when marking a boundary. Thus, the result is a two line boundary (without any area; however, sometimes a false area is reported)