How to adjust the contrast of an image in PyTorch
In this article, we are going to see how to adjust the contrast of an image in PyTorch using Python. We can adjust the contrast of an image by using the adjust_contrast() method.
adjust_contrast() method
adjust_contrast() method accepts the PIL and tensor images as input. tensor image is a tensor with [C, H, W] shape, where C is the number of channels, and H W is the image height and width respectively. This method also accepts a batch of tensors as input with shape [B, C, H, W] where B is the number of images in the batch. and C, H, and W are the number of channels image height and width respectively. This method returns a Contrast adjusted image. before moving further let’s see the syntax of the adjust_contrast() method.
Syntax: adjust_contrast(img, contrast_factor)
Parameters:
- img: This is our PIL or tensor image of which the contrast is to be adjusted.
- contrast_factor: This is a non-negative float number. 0 and 1 gives solid gray original image respectively.
Returns: This method returns a Contrast adjusted image:
The below image is used for demonstration:
Example 1:
In this example, we are adjusting the contrast of an image in PyTorch when the contrast_factor is 0.5.
Python3
# Import the required libraries import torch from PIL import Image import torchvision.transforms.functional as con # read the input image from computer input_img = Image. open ( 'image.png' ) # adjust the contrast of the image input_img = con.adjust_contrast(input_img, 0.5 ) # display result input_img.show() |
Output:
Example 2:
In this example, we are adjusting the contrast of an image in PyTorch when the contrast_factor is 0.
Python3
# Import the required libraries import torch from PIL import Image import torchvision.transforms.functional as con # read the input image from computer input_img = Image. open ( 'a.png' ) # adjust the contrast of the image input_img = con.adjust_contrast(input_img, 0 ) # display result input_img.show() |
Output
Example 3:
In this example, we are adjusting the contrast of an image in PyTorch when the contrast_factor is 1.
Python3
# Import the required libraries import torch from PIL import Image import torchvision.transforms.functional as con # read the input image from computer input_img = Image. open ( 'a.png' ) # adjust the contrast of the image input_img = con.adjust_contrast(input_img, 1 ) # display result input_img.show() |
Output