skimage2.draw.random_shapes

skimage2.draw.random_shapes(image_shape, max_shapes, min_shapes=1, min_size=2, max_size=None, num_channels=3, shape=None, intensity_range=None, allow_overlap=False, num_trials=100, rng=None, *, channel_axis=-1)

Generate an image with random shapes, labeled with bounding boxes.

The image is populated with random shapes with random sizes, random locations, and random colors, with or without overlap.

Shapes have random (row, col) starting coordinates and random sizes bounded by min_size and max_size. It can occur that a randomly generated shape will not fit the image at all. In that case, the algorithm will try again with new starting coordinates a certain number of times. However, it also means that some shapes may be skipped altogether. In that case, this function will generate fewer shapes than requested.

Parameters:

image_shapetuple

The number of rows and columns of the image to generate.

max_shapesint

The maximum number of shapes to (attempt to) fit into the shape.

min_shapesint, optional

The minimum number of shapes to (attempt to) fit into the shape.

min_sizeint, optional

The minimum dimension of each shape to fit into the image.

max_sizeint, optional

The maximum dimension of each shape to fit into the image.

num_channelsint, optional

Number of channels in the generated image. If 1, generate monochrome images, else color images with multiple channels. Ignored if multichannel is set to False.

shape{“rectangle”, “circle”, “triangle”, “ellipse”, None}, optional

The name of the shape to generate or None to pick random ones.

intensity_range{tuple of tuples of uint8, tuple of uint8}, optional

The range of values to sample pixel values from. For grayscale images the format is (min, max). For multichannel - ((min, max),) if the ranges are equal across the channels, and ((min_0, max_0), … (min_N, max_N)) if they differ. As the function supports generation of uint8 arrays only, the maximum range is (0, 255). If None, set to (0, 254) for each channel reserving color of intensity = 255 for background.

allow_overlapbool, optional

If True, allow shapes to overlap.

num_trialsint, optional

How often to attempt to fit a shape into the image before skipping it.

rng{numpy.random.Generator, int}, optional

Pseudo-random number generator. By default, a PCG64 generator is used (see numpy.random.default_rng()). If rng is an int, it is used to seed the generator.

channel_axisint or None, optional

If None, the image is assumed to be a grayscale (single channel) image. Otherwise, this parameter indicates which axis of the array corresponds to channels.

Added in version 0.19: channel_axis was added in 0.19.

Returns:

imagendarray of dtype uint8

An image with the fitted shapes.

labelslist

A list of labels, one per shape in the image. Each label is a (category, ((r0, r1), (c0, c1))) tuple specifying the category and bounding box coordinates of the shape.

Examples

>>> import _skimage2.draw
>>> image, labels = _skimage2.draw.random_shapes((32, 32), max_shapes=3)
>>> image
array([
   [[255, 255, 255],
    [255, 255, 255],
    [255, 255, 255],
    ...,
    [255, 255, 255],
    [255, 255, 255],
    [255, 255, 255]]], dtype=uint8)
>>> labels
[('circle', ((22, 18), (25, 21))),
 ('triangle', ((5, 6), (13, 13)))]