noise_demo.py

import numpy as np
import noise
import cv2

WIDTH     = 600
HEIGHT    = 600
FREQUENCY = 0.001


def generate_noise_map(
        shape = (WIDTH, HEIGHT),
        frequency = FREQUENCY,
):
    octaves = 6
    persistence = 0.5
    lacunarity = 2.0

    seed = np.random.randint(0, 1000000)

    world = np.zeros(shape)
    for x in range(shape[0]):
        for y in range(shape[1]):
            world[y][x] = noise.pnoise3(x*frequency,
                                        y*frequency,
                                        seed,
                                        octaves=octaves,
                                        persistence=persistence,
                                        lacunarity=lacunarity,
                                        repeatx=WIDTH,
                                        repeaty=HEIGHT,
                                        base=0)

    world = (world - world.min())/(world.max()-world.min())
    return world


def get_dummy_annotations():
    N = 30
    a = np.zeros((HEIGHT, WIDTH, 3), dtype=np.uint8)

    annotations = []
    for j in range(N):
        for i in range(N):
            x = int((i+0.5)/N  * WIDTH)
            y = int((j+0.5)/N  * HEIGHT)

            annotations.append([x, y])

    return annotations


def deform(annotations):
    noise_map_x = generate_noise_map()
    noise_map_y = generate_noise_map()

    noise_strength = 40

    for anno in annotations:
        x = anno[0]
        y = anno[1]
        xd = noise_strength * (noise_map_x[y, x]*2 - 1)
        yd = noise_strength * (noise_map_y[y, x]*2 - 1)
        anno[0] = int(x + xd)
        anno[1] = int(y + yd)

    cv2.imwrite('noise_map_x.png', (255*noise_map_x).astype(np.uint8))
    cv2.imwrite('noise_map_y.png', (255*noise_map_y).astype(np.uint8))

    return annotations


def render(annotations):
    img = np.zeros((HEIGHT, WIDTH, 3))

    for anno in annotations:
        x = anno[0]
        y = anno[1]
        cv2.rectangle(img, (x, y), (x+2, y+2), (0, 255, 0), 1)

    return img

def demo():

    annotations = get_dummy_annotations()
    img = render(annotations)
    cv2.imwrite('annotations_original.png', img)

    annotations = deform(annotations)
    img = render(annotations)
    cv2.imwrite('annotations_deformed.png', img)


if __name__ == '__main__':
    demo()