imagecollection

ImageCollection

class skimage.io.ImageCollection(load_pattern, conserve_memory=True, load_func=None, **load_func_kwargs) [source]

Bases: object

Load and manage a collection of image files.

Note that files are always stored in alphabetical order. Also note that slicing returns a new ImageCollection, not a view into the data.

Parameters:

Parameters:	load_pattern : str or list Pattern glob or filenames to load. The path can be absolute or relative. Multiple patterns should be separated by os.pathsep, e.g. ‘/tmp/work/.png:/tmp/other/.jpg’. Also see implementation notes below. conserve_memory : bool, optional If True, never keep more than one in memory at a specific time. Otherwise, images will be cached once they are loaded.
Other Parameters:
	load_func : callable `imread` by default. See notes below.

load_pattern : str or list

Pattern glob or filenames to load. The path can be absolute or relative. Multiple patterns should be separated by os.pathsep, e.g. ‘/tmp/work/.png:/tmp/other/.jpg’. Also see implementation notes below.

conserve_memory : bool, optional

If True, never keep more than one in memory at a specific time. Otherwise, images will be cached once they are loaded.

Other Parameters:

load_func : callable

imread by default. See notes below.

Notes

ImageCollection can be modified to load images from an arbitrary source by specifying a combination of load_pattern and load_func. For an ImageCollection ic, ic[5] uses load_func(file_pattern[5]) to load the image.

Imagine, for example, an ImageCollection that loads every tenth frame from a video file:

class AVILoader:
    video_file = 'myvideo.avi'

    def __call__(self, frame):
        return video_read(self.video_file, frame)

avi_load = AVILoader()

frames = range(0, 1000, 10) # 0, 10, 20, ...
ic = ImageCollection(frames, load_func=avi_load)

x = ic[5] # calls avi_load(frames[5]) or equivalently avi_load(50)

Another use of load_func would be to convert all images to uint8:

def imread_convert(f):
    return imread(f).astype(np.uint8)

ic = ImageCollection('/tmp/*.png', load_func=imread_convert)

For files with multiple images, the images will be flattened into a list and added to the list of available images. In this case, load_func should accept the keyword argument img_num.

Examples

>>> import skimage.io as io
>>> from skimage import data_dir

>>> coll = io.ImageCollection(data_dir + '/chess*.png')
>>> len(coll)
2
>>> coll[0].shape
(200, 200)

>>> ic = io.ImageCollection('/tmp/work/*.png:/tmp/other/*.jpg')

Attributes

files (list of str) If a glob string is given for load_pattern, this attribute stores the expanded file list. Otherwise, this is simply equal to load_pattern.

__init__(load_pattern, conserve_memory=True, load_func=None, **load_func_kwargs) [source]: Load and manage a collection of images.

concatenate() [source]

Concatenate all images in the collection into an array.

Returns:

Returns:	ar : np.ndarray An array having one more dimension than the images in `self`.
Raises:	ValueError If images in the `ImageCollection` don’t have identical shapes.

ar : np.ndarray

An array having one more dimension than the images in self.

Raises:

ValueError

If images in the ImageCollection don’t have identical shapes.