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.
Answers:
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.
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
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
# Create an array with a required colours
# The colours are given in BGR [B, G, R]
# The array is created with values of ones, the size is (H, W, Channels)
# The format of the array is uint8
# This array needs to be converted to an image of type uint8
selectedColor = [75, 19, 77] * np.ones((640, 480, 3), np.uint8)
imgSelectedColor = np.uint8(np.absolute(selectedColor))
Just regarding the headline of this question, I did need a white image as well as a pillow input. And the solutions presented here did not work for me.
Therefore here a different way to generate white images for other purposes:
from PIL import Image
img = Image.new('RGB', (200, 50), color = (255,255,255))
Size and color may be changed in the 2nd and 3rd parameter of the Image.new()-function.
And if you want to write something on this image or save it, this would be example code for this.
from PIL import ImageFont, ImageDraw
fnt = ImageFont.truetype("Pillow/Tests/fonts/FreeMono.ttf", 30)
ImageDraw.Draw(img).text((0,0), "hello world", font=fnt, fill=(0,0,0))
img.save('test.jpg')
The headline is too broad and shows up at Google first. I needed a white image and used PIL and numpy. PILlow actually works well with numpy
import numpy as np
from PIL import Image
img = np.zeros([100,100,3],dtype=np.uint8)
img.fill(255) # numpy array!
im = Image.fromarray(img) #convert numpy array to image
im.save('whh.jpg')
Here’s a simple way to create a white image with a python one liner.
$ python3 -c "from PIL import Image;Image.new('RGB', (1900, 1080), color = (255,255,255)).save('Img.jpg')"
This will create a white image with a width of 1900 and hight of 1080.
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.
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.
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
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
# Create an array with a required colours
# The colours are given in BGR [B, G, R]
# The array is created with values of ones, the size is (H, W, Channels)
# The format of the array is uint8
# This array needs to be converted to an image of type uint8
selectedColor = [75, 19, 77] * np.ones((640, 480, 3), np.uint8)
imgSelectedColor = np.uint8(np.absolute(selectedColor))
Just regarding the headline of this question, I did need a white image as well as a pillow input. And the solutions presented here did not work for me.
Therefore here a different way to generate white images for other purposes:
from PIL import Image
img = Image.new('RGB', (200, 50), color = (255,255,255))
Size and color may be changed in the 2nd and 3rd parameter of the Image.new()-function.
And if you want to write something on this image or save it, this would be example code for this.
from PIL import ImageFont, ImageDraw
fnt = ImageFont.truetype("Pillow/Tests/fonts/FreeMono.ttf", 30)
ImageDraw.Draw(img).text((0,0), "hello world", font=fnt, fill=(0,0,0))
img.save('test.jpg')
The headline is too broad and shows up at Google first. I needed a white image and used PIL and numpy. PILlow actually works well with numpy
import numpy as np
from PIL import Image
img = np.zeros([100,100,3],dtype=np.uint8)
img.fill(255) # numpy array!
im = Image.fromarray(img) #convert numpy array to image
im.save('whh.jpg')
Here’s a simple way to create a white image with a python one liner.
$ python3 -c "from PIL import Image;Image.new('RGB', (1900, 1080), color = (255,255,255)).save('Img.jpg')"
This will create a white image with a width of 1900 and hight of 1080.