Random Walk Image Generation

RandomWalkImage.ipynb

RandomWalkImage.py

"""
Random Walk Image Generator

@Author: Shubhanshu Mishra
@Website: http://shubhanshu.com
@LICENSE: MIT
"""

# coding: utf-8

# In[1]:

import numpy as np
import matplotlib.pyplot as plt

# In[2]:
def get_color(colors=None, color_channels=3):
    if colors is None:
        return np.random.rand(color_channels)
    else:
        return colors[np.random.randint(len(colors))]


def gen_image(n = 200, walks = 5, fig_dim = 10, density = 0.5, bg_grey = 1, color_change_steps=50,\
              colors_rgb = True, colors = None, filename=None, verbose=False):
    color_channels = 3
    if not colors_rgb:
        color_channels = 1
    figsize = (fig_dim, )*2
    img = np.ones((n,n,3)) * bg_grey
    mat = np.zeros((n,n))
    for i in xrange(walks):
        init_x, init_y = np.random.randint(0,2, size=(2))
        color = get_color(colors=colors, color_channels=color_channels)
        img[init_x, init_y] = color
        mat[init_x, init_y] = 1
        num_steps = np.random.randint(int(n*n*density))
        num_steps = int(np.random.rand()*n*n*density)
        next_x, next_y = init_x, init_y
        change_steps = 0
        for j in xrange(num_steps):
            nudge = np.random.randint(-1,2, size=2)
            next_x, next_y = (next_x + nudge[0]) % n, (next_y + nudge[1]) % n
            if mat[next_x, next_y] == 1 or change_steps >= color_change_steps:
                color = get_color(colors=colors, color_channels=color_channels)
                change_steps = 0
            change_steps += 1
            img[next_x, next_y] = color
        if verbose:
            print "Walk %s with %s steps" % (i, num_steps)
    plt.clf()
    plt.figure(figsize=figsize)
    plt.imshow(img)
    plt.axis('off')
    if filename is not None:
        plt.savefig(filename)
    else:
        plt.show()

# In[3]:

# In[ ]:

if __name__ == "__main__":
    base_file = "rand_img_%s.png"
    num_images = 500
    for i in xrange(num_images):
        gen_image(filename=base_file % i)
        print "Finished generating %s images" % (i + 1)


# In[ ]: