How to create a white image in Python?

Question

Upon doing my homework, I stumbled across a problem concerning Python and image manipulation. I must say, using the Image lib is not an option. So here it is

from scipy.misc import imread,imsave
from numpy import zeros

imga = zeros([100,100,3])
h = len(imga)
w = len(imga[0])

for y in range(h):
    for x in range(w):
        imga[y,x] = [255,255,255]

imsave("Result.jpg",imga)

I would assume it makes my picture white, but it turns it black, and I have no idea why It's not about the code (and I know it looks very ugly). Its just about the fact, that it is a black image.

Answer 1

Every color in an image is represented by one byte. So to create an image array, you should set it's dtype to uint8.

And, you don't need for-loop to set every elements to 255, you can use fill() method or slice index:

import numpy as np
img = np.zeros([100,100,3],dtype=np.uint8)
img.fill(255) # or img[:] = 255

Answer 2

Easy! Check the below Code:

whiteFrame = 255 * np.ones((1000,1000,3), np.uint8)

255 is the color for filling the bytes.

1000, 1000 is the size of the image.

3 is the color channel for the image.

And unit8 is the type

Goodluck

Answer 3

When creating imga, you need to set the unit type. Specifically, change the following line of code:

imga = zeros([100,100,3], dtype=np.uint8)

And, add the following to your imports:

import numpy as np

That gives a white image on my machine.