VLFEAT

NAME
DESCRIPTION
FILE SPECIFIERS (FILESPEC)
SEE ALSO

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NAME

VLFeat − VisionLab Features Library

DESCRIPTION

VLFeat is a collection of computer vision algorithms with a special focus on image features such as SIFT and MSER.

The functionalities offered by the library can be accessed either through its API, or by means of command line and MATLAB programs. See the SEE ALSO section for a list of the related command line programs and for a pointer to the general documentation of the library.

FILE SPECIFIERS (FILESPEC)

Some commands in VLFeat make use of ‘file specifiers’ to associate to one or more input files the appropriate output/auxiliary files. A file specifier is a string such as ‘ascii://%.txt’ and contains two pieces of information:

	•		The file format (in this case ascii). The supported formats depend on the particular application. Two common formats are ascii and bin(ary).
	•		A name transformation rule (in this case %.txt). This is used to transform the name an input file into the name of the corresponding output/auxiliary file. The transformed name is comput by extracting the basename of the input file substituting it to all occurences of the wildcard characer ‘%’ in the transformation rule (‘%%’) passes the wildcard character untouched.

Recall that the basename of a file name is obtained by stripping the directory prefix (everything from the beginning up to the last ‘/’ or ‘\’ character) and extension (everything from the last ‘.’ characeter (excluding the prefix) to the end).

For instance, the filespec ‘ascii://%.txt’ and the input file ‘test.data’ specify a file named ‘test.txt’ in ascii (text) format.

Partial file specifiers
Normally, a program provides default values for its file specifiers. In this case, partial file specifier (with only the file format or the name transformation rule are acceptable).

File specifiers equivalent to a file name
A partial specifier such as ‘file.txt’ is in effect equivalent to the file name ‘file.txt’. If the specifier is used in conjunction with multiple input files, this causes the same file to be accessed multile times.

SEE ALSO

sift(1), mser(1)

A. Vedaldi and B. Fulkerson. VLFeat Library. http://www.vlfeat.org/

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