Simple Python Script to Distort Images

The script itself looks like this:

import numpy as np
from PIL import Image

def quad_as_rect(quad):
if quad[0] != quad[2]: return False
if quad[1] != quad[7]: return False
if quad[4] != quad[6]: return False
if quad[3] != quad[5]: return False
return True

def quad_to_rect(quad):
assert(len(quad) == 8)
assert(quad_as_rect(quad))
return (quad[0], quad[1], quad[4], quad[3])

def rect_to_quad(rect):
assert(len(rect) == 4)
return (rect[0], rect[1], rect[0], rect[3], rect[2], rect[3], rect[2], rect[1])

def shape_to_rect(shape):
assert(len(shape) == 2)
return (0, 0, shape[0], shape[1])

def griddify(rect, w_div, h_div):
w = rect[2] - rect[0]
h = rect[3] - rect[1]
x_step = w / float(w_div)
y_step = h / float(h_div)
y = rect[1]
grid_vertex_matrix = []
for _ in range(h_div + 1):
grid_vertex_matrix.append([])
x = rect[0]
for _ in range(w_div + 1):
grid_vertex_matrix[-1].append([int(x), int(y)])
x += x_step
y += y_step
grid = np.array(grid_vertex_matrix)
return grid

def distort_grid(org_grid, max_shift):
new_grid = np.copy(org_grid)
x_min = np.min(new_grid[:, :, 0])
y_min = np.min(new_grid[:, :, 1])
x_max = np.max(new_grid[:, :, 0])
y_max = np.max(new_grid[:, :, 1])
new_grid += np.random.randint(- max_shift, max_shift + 1, new_grid.shape)
new_grid[:, :, 0] = np.maximum(x_min, new_grid[:, :, 0])
new_grid[:, :, 1] = np.maximum(y_min, new_grid[:, :, 1])
new_grid[:, :, 0] = np.minimum(x_max, new_grid[:, :, 0])
new_grid[:, :, 1] = np.minimum(y_max, new_grid[:, :, 1])
return new_grid

def grid_to_mesh(src_grid, dst_grid):
assert(src_grid.shape == dst_grid.shape)
mesh = []
for i in range(src_grid.shape[0] - 1):
for j in range(src_grid.shape[1] - 1):
src_quad = [src_grid[i , j , 0], src_grid[i , j , 1],
src_grid[i + 1, j , 0], src_grid[i + 1, j , 1],
src_grid[i + 1, j + 1, 0], src_grid[i + 1, j + 1, 1],
src_grid[i , j + 1, 0], src_grid[i , j + 1, 1]]
dst_quad = [dst_grid[i , j , 0], dst_grid[i , j , 1],
dst_grid[i + 1, j , 0], dst_grid[i + 1, j , 1],
dst_grid[i + 1, j + 1, 0], dst_grid[i + 1, j + 1, 1],
dst_grid[i , j + 1, 0], dst_grid[i , j + 1, 1]]
dst_rect = quad_to_rect(dst_quad)
mesh.append([dst_rect, src_quad])
return mesh

im = Image.open("./image.jpg")
dst_grid = griddify(shape_to_rect(im.size), 4, 4)
src_grid = distort_grid(dst_grid, 50)
mesh = grid_to_mesh(src_grid, dst_grid)
im = im.transform(im.size, Image.MESH, mesh)
im.save("./image.jpg")

Running a script:

python3 name.py

im = Image.open("./image.jpg") – path and name of the image to be generated,

im.save("./image.jpg") – path and name of the generated image.