The brightness of an image is a measure of its intensity after the image has been captured. To adjust the brightness of an image, we apply adjust_brightness(). It's one of the functional transforms provided by the torchvision.transforms module. This module contains many important functional transformations that can be used to manipulate the image data.
adjust_brightness() transformation accepts both PIL and tensor images. A tensor image is a PyTorch tensor with shape [C, H, W], where C is number of channels, H is image height, and W is image width. This transform also accepts a batch of tensor images. A batch of tensor images is a tensor with [B, C, H, W] where B is the number of images in the batch. If the image is neither a PIL image nor a tensor image, then we first convert it to a tensor image and then apply the adjust_brightness().
img - Image of which the brightness is to be adjusted. It is a PIL image or torch tensor. It may be a single image or a batch of images.
brightness_factor - A non-negative float number. 0 gives a black image, 1 gives the original image.
It returns the brightness adjusted image.
To adjust the brightness of an image, one could follow the steps given below
Import the required libraries. In all the following examples, the required Python libraries are torch, Pillow, and torchvision. Make sure you have already installed them.
import torch import torchvision import torchvision.transforms.functional as F from PIL import Image
Read the input image. The input image is a PIL image or a torch tensor.
img = Image.open('Nature1.jpg')
Adjust the brightness of the image with the desired brightness factor.
img = F.adjust_brightness(img, 0.3)
Visualize the brightness adjusted image.
We will use this image as the input file in the following examples.
In the following Python program, we adjust the brightness of the image with a brightness_factor=0.3.
# Import the required libraries import torch from PIL import Image import torchvision.transforms.functional as F # read the input image img = Image.open('Nature1.jpg') # adjust the brightness of image img = F.adjust_brightness(img, 0.3) # display the brightness adjusted image img.show()
In the following Python program, we adjust the brightness of the image with a brightness_factor=1.6.
import torch from PIL import Image import torchvision.transforms.functional as F img = Image.open('Nature1.jpg') img.show() img = F.adjust_brightness(img, 1.6) img.show()