Data files

Access data file shipped with the Toolbox.

machinevisiontoolbox.base.data.mvtb_load_matfile(filename)[source]

Load toolbox mat format data file

Parameters:

filename (str) – relative pathname of datafile

Raises:

ValueError – File does not exist

Returns:

contents of mat data file

Return type:

dict

Reads a MATLAB format mat file which can contain multiple variables, in a binary or ASCII format. Returns a dict where the keys are the variable names and the values are NumPy arrays.

Note

  • Uses SciPy io.loadmat to do the work.

  • If the filename has no path component it will be first be looked for in the folder machinevisiontoolbox/data, then the current working directory.

Seealso:

mvtb_path_to_datafile scipy.io.loadmat

machinevisiontoolbox.base.data.mvtb_load_jsonfile(filename)[source]

Load toolbox JSON format data file

Parameters:

filename (str) – relative pathname of datafile

Raises:

ValueError – File does not exist

Returns:

contents of JSON data file

Return type:

dict

Reads a JSON format file which can contain multiple variables and return a dict where the keys are the variable names and the values are Python data types.

Note

  • If the filename has no path component it will be first be looked for in the folder machinevisiontoolbox/data, then the current working directory.

Seealso:

mvtb_path_to_datafile

machinevisiontoolbox.base.data.mvtb_load_data(filename, handler, **kwargs)[source]

Load toolbox data file

Parameters:
  • filename (str) – relative pathname of datafile

  • handler (callable) – function to read data

Raises:

ValueError – File does not exist

Returns:

data object

Resolves the relative pathname to an absolute name and then invokes the data reading function:

handler(abs_file_name, **kwargs)

For example:

data = mvtb_load_data('data/foo.dat', lambda f: data_load(open(f, 'r')))

Note

If the filename has no path component it will first be looked for in the folder machinevisiontoolbox/data, then the current working directory.

Seealso:

mvtb_path_to_datafile

machinevisiontoolbox.base.data.mvtb_path_to_datafile(*filename, local=True, string=False)[source]

Get absolute path to file in MVTB data package

Parameters:
  • filename (str) – pathname of image file

  • local (bool) – search for file locally first, default True

Raises:

FileNotFoundError – File does not exist

Returns:

Absolute path

Return type:

Path

The data associated with the Machine Vision Toolbox for Python is shipped as a separate package.

The positional arguments are joined, like os.path.join, for example:

mvtb_path_to_datafile('data', 'solar.dat')  # data/solar.dat

If local is True then ~ is expanded and if the file exists, the path is made absolute, and symlinks resolved:

mvtb_path_to_datafile('foo.dat')         # find ./foo.dat
mvtb_path_to_datafile('~/foo.dat')       # find $HOME/foo.dat

Otherwise, the file is sought within the mvtbdata package and if found, return that absolute path.

Example:

>>> from machinevisiontoolbox import mvtb_path_to_datafile
>>> mvtb_path_to_datafile('data', 'solar.dat')   # read mvtbdata/data/solar.dat
PosixPath('/opt/hostedtoolcache/Python/3.9.20/x64/lib/python3.9/site-packages/mvtbdata/data/solar.dat')