simulated_dark_image.py

#!/usr/bin/env python
"""Simple numpy script to generate a simulated dark image showing hot pixels"""

import numpy as np
from scipy import ndimage, misc
import matplotlib.pyplot as plt

# generate the image of zeros
im = np.zeros((1024, 1280))

# generate the coordinates for the hot pixels
n_hot = 400
hot_x = np.random.random_integers(0, im.shape[0]-2, n_hot)
hot_y = np.random.random_integers(0, im.shape[1]-2, n_hot)

# make the pixels two by two so they will be
# more visible
im[hot_x, hot_y] = 4095
im[hot_x+1, hot_y] = 4095
im[hot_x, hot_y+1] = 4095
im[hot_x+1, hot_y+1] = 4095

plt.imshow(im, cmap=plt.cm.gray)

misc.imsave('darks.png', im)