how to get random pixel index from binary image with value 1 in python?

user_8238751 0
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I have a binary image of large size (2000x2000). In this image most of the pixel values are zero and some of them are 1. I need to get only 100 randomly chosen pixel coordinates with value 1 from image. I am beginner in python, so please answer.

pixel random python
4 Answers

Use below code:

import numpy as np
y_idx, x_idx = np.where(image==1)   #list of all the indices with pixel value 1

for i in range(0,100):
    rand_idx = np.random.choice(x_idx)   #randomly choose any element in the x_idx list
    x = x_idx[rand_idx]
    y = y_idx[rand_idx]
    #--further code with x,y--
user_84865310

here is another answer that might save some memory storage, or at least a for loop..

import numpy as np
random_image = np.random.uniform(0, 1, size=(2000, 2000)) > 0.5

sel_index = np.random.choice(np.argwhere(random_image.ravel()).ravel(), size=100)
random_x, random_y = np.unravel_index(sel_index, random_bin.shape)

I just like the usage of unravel :)

user_63292840
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