Brighten low-light image
Brighten a low-light image using default parameters. View the original image and the lightened version of the image.
A = imread('lowlight_2.jpg'); B = imlocalbrighten(A); figure, imshowpair(A,B,'montage')
Brighten the low-light image again, this time specifying the amount of lightening to apply to the image. View the original image and this lightened version of the image.
A = imread('lowlight_2.jpg'); B2 = imlocalbrighten(A,0.8); figure, imshowpair(A,B2,'montage')
AlphaBlend option to preserve content from the original image in the lightened image. This time, view the lightened output image from the first example with the alpha blended output image. Compare the detail shown in the wall above arched entryway near the center of the image in the alpha-blended version with the original lightened image.
A = imread('lowlight_2.jpg'); Bblend = imlocalbrighten(A,'AlphaBlend',true); figure, imshowpair(B,Bblend,'montage')
Get the estimated darkness-per-pixel matrix return value. View the original image and the darkness estimate matrix.
A = imread('lowlight_2.jpg'); [~,D] = imlocalbrighten(A); figure, imshowpair(A,D,'montage')
A— Image to be brightened
Image to be brightened, specified as an RGB image or grayscale image.
amount— Amount to brighten image
1(default) | number in the range [0, 1]
Amount to brighten the image, specified as a number in the range [0, 1]. When the
1 (the default),
brightens the low-light areas of
A as much as possible. When the
imlocalbrighten returns the input
alphaBlend— Alpha blend input and enhanced image
Alpha blend input and enhanced image, specified as
true. Alpha blending combines the input image with the enhanced
image to preserve brighter areas of the input image. When
imlocalbrighten uses the estimate of darkness matrix,
D, to preserve content of the input image proportional to the
amount of light in each pixel.
B— Brightened image
Brightened image, returned as a numeric array of the same size and data type as the
D— Darkness estimate
Darkness estimate of each pixel in the input image, returned as a numeric matrix.
D is the same size as the first two dimensions of the input
 Dong, X., G. Wang, Y. Pang, W. Li, J. Wen, W. Meng, and Y. Lu. "Fast efficient algorithm for enhancement of low lighting video." Proceedings of IEEE® International Conference on Multimedia and Expo (ICME). 2011, pp. 1–6.
 He, Kaiming. "Single Image Haze Removal Using Dark Channel Prior." Thesis, The Chinese University of Hong Kong, 2011.
 Dubok Park; Hyungjo Park; David K. Han; Hanseok Ko "Single Image Dehazing with Image Entropy and Information Fidelity." ICIP, 2014.