# -*- coding: utf-8 -*-
"""
Génère des images aléatoires.
:githublink:`%|py|6`
"""
import math
import numpy
import numpy.random as nprnd # pylint: disable=E1101
[docs]def random_noise_image(size, ratio=0.1):
"""
Construit une image blanche de taille *size*,
noircit aléatoirement *ratio x nb pixels*
pixels.
:param size: taille de l'image
:param ratio: proportion de pixels à noircir
:return: :epkg:`numpy:array`
:githublink:`%|py|20`
"""
img = numpy.zeros((size[1], size[0]), dtype=numpy.float32)
nb = int(ratio * size[0] * size[1])
xr = nprnd.randint(0, size[0] - 1, nb)
yr = nprnd.randint(0, size[1] - 1, nb)
img[yr, xr] = 1
return img
[docs]def random_segment_image(image, lmin=0.1, lmax=1., noise=0.01, density=1.):
"""
Ajoute un segment aléatoire à une image.
Génère des points le long d'un segment aléatoire.
:param image: :epkg:`numpy:array` (modifié par la fonction)
:param lmin: taille minimal du segment
:param lmax: taille maximam du segment
:param density: nombre de pixel à tirer le long de l'axe
:param noise: bruit
:return: dictionary with *size, angle, x1, y1, x2, y2, nbpoints*
:githublink:`%|py|40`
"""
def move_coordinate(x1, y1, x2, y2, X, Y):
if x2 < 0:
x1 -= x2
x2 = 0
x1 = min(max(x1, 0), X - 1)
x2 = min(max(x2, 0), X - 1)
y1 = min(max(y1, 0), Y - 1)
y2 = min(max(y2, 0), Y - 1)
size = int(((x1 - x2)**2 + (y1 - y2) ** 2) ** 0.5)
return x1, y1, x2, y2, size
mind = min(image.shape)
lmin = int(mind * lmin)
lmax = int(mind * lmax)
size = nprnd.randint(lmin, lmax)
angle = nprnd.random() * math.pi # pylint: disable=E1101
x1 = nprnd.randint(
image.shape[1] - int(size * abs(math.cos(angle)) - 1))
y1 = nprnd.randint(image.shape[0] - int(size * math.sin(angle) - 1))
x2 = x1 + size * math.cos(angle)
y2 = y1 + size * math.sin(angle)
x1, y1, x2, y2, size = move_coordinate(
x1, y1, x2, y2, image.shape[1], image.shape[0])
t = nprnd.randint(0, size, int(size * density))
xs = t * math.cos(angle) + x1
ys = t * math.sin(angle) + x2
noise = nprnd.randn( # pylint: disable=E1101
xs.shape[0] * 2).reshape(xs.shape[0], 2) * noise * mind
xs += noise[:, 0]
ys += noise[:, 1]
xs = numpy.maximum(xs, numpy.zeros(xs.shape[0])) # pylint: disable=E1111
ys = numpy.maximum(ys, numpy.zeros(
xs.shape[0])) # pylint: disable=E1111,E1101,E1136
xs = numpy.minimum(xs, numpy.zeros( # pylint: disable=E1101,E1136
xs.shape[0]) + image.shape[1] - 1) # pylint: disable=E1111,E1101,E1136
ys = numpy.minimum(ys, numpy.zeros( # pylint: disable=E1101,E1136
xs.shape[0]) + image.shape[0] - 1) # pylint: disable=E1111,E1101,E1136
xs = xs.astype(numpy.int32) # pylint: disable=E1101
ys = ys.astype(numpy.int32) # pylint: disable=E1101
image[ys, xs] = 1
res = dict(size=size, angle=angle, x1=x1, y1=y1, x2=x2, y2=y2,
nbpoints=xs.shape[0]) # pylint: disable=E1136
return res