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"""
Common image operations
Reference: https://github.com/hendrycks/robustness
Hacked together for STR by: Rowel Atienza
"""
import cv2
import numpy as np
from scipy.ndimage import zoom as scizoom
def clipped_zoom(img, zoom_factor):
h = img.shape[1]
# ceil crop height(= crop width)
ch = int(np.ceil(h / float(zoom_factor)))
top = (h - ch) // 2
img = scizoom(img[top:top + ch, top:top + ch], (zoom_factor, zoom_factor, 1), order=1)
# trim off any extra pixels
trim_top = (img.shape[0] - h) // 2
return img[trim_top:trim_top + h, trim_top:trim_top + h]
def disk(radius, alias_blur=0.1, dtype=np.float32):
if radius <= 8:
coords = np.arange(-8, 8 + 1)
ksize = (3, 3)
else:
coords = np.arange(-radius, radius + 1)
ksize = (5, 5)
x, y = np.meshgrid(coords, coords)
aliased_disk = np.asarray((x ** 2 + y ** 2) <= radius ** 2, dtype=dtype)
aliased_disk /= np.sum(aliased_disk)
# supersample disk to antialias
return cv2.GaussianBlur(aliased_disk, ksize=ksize, sigmaX=alias_blur)
# modification of https://github.com/FLHerne/mapgen/blob/master/diamondsquare.py
def plasma_fractal(mapsize=256, wibbledecay=3, rng=None):
"""
Generate a heightmap using diamond-square algorithm.
Return square 2d array, side length 'mapsize', of floats in range 0-255.
'mapsize' must be a power of two.
"""
assert (mapsize & (mapsize - 1) == 0)
maparray = np.empty((mapsize, mapsize), dtype=np.float_)
maparray[0, 0] = 0
stepsize = mapsize
wibble = 100
if rng is None:
rng = np.random.default_rng()
def wibbledmean(array):
return array / 4 + wibble * rng.uniform(-wibble, wibble, array.shape)
def fillsquares():
"""For each square of points stepsize apart,
calculate middle value as mean of points + wibble"""
cornerref = maparray[0:mapsize:stepsize, 0:mapsize:stepsize]
squareaccum = cornerref + np.roll(cornerref, shift=-1, axis=0)
squareaccum += np.roll(squareaccum, shift=-1, axis=1)
maparray[stepsize // 2:mapsize:stepsize, stepsize // 2:mapsize:stepsize] = wibbledmean(squareaccum)
def filldiamonds():
"""For each diamond of points stepsize apart,
calculate middle value as mean of points + wibble"""
drgrid = maparray[stepsize // 2:mapsize:stepsize, stepsize // 2:mapsize:stepsize]
ulgrid = maparray[0:mapsize:stepsize, 0:mapsize:stepsize]
ldrsum = drgrid + np.roll(drgrid, 1, axis=0)
lulsum = ulgrid + np.roll(ulgrid, -1, axis=1)
ltsum = ldrsum + lulsum
maparray[0:mapsize:stepsize, stepsize // 2:mapsize:stepsize] = wibbledmean(ltsum)
tdrsum = drgrid + np.roll(drgrid, 1, axis=1)
tulsum = ulgrid + np.roll(ulgrid, -1, axis=0)
ttsum = tdrsum + tulsum
maparray[stepsize // 2:mapsize:stepsize, 0:mapsize:stepsize] = wibbledmean(ttsum)
while stepsize >= 2:
fillsquares()
filldiamonds()
stepsize //= 2
wibble /= wibbledecay
maparray -= maparray.min()
return maparray / maparray.max() |