L A B COLOR CONVERTER HOW TO
L A B COLOR CONVERTER INSTALL

Step 5: Subtract the mean of the L*a*b* channels of the target image from target channels.Step 4: Compute the mean and standard deviation of each of the L*a*b* channels for the source and target images.Step 3: Split the channels for both the source and target.The L*a*b* color space does a substantially better job mimicking how humans interpret color than the standard RGB color space, and as you’ll see, works very well for color transfer. The L*a*b* color space models perceptual uniformity, where a small change in an amount of color value should also produce a relatively equal change in color importance. Step 2: Convert both the source and the target image to the L*a*b* color space.In the figure at the top of this page, the sunset image on the left is my source, the middle image is my target, and the image on the right is the color space of the source applied to the target.

The source image contains the color space that you want your target image to mimic. Step 1: Input a source and a target image.In this paper, Reinhard and colleagues demonstrate that by utilizing the L*a*b* color space and the mean and standard deviation of each L*, a*, and b* channel, respectively, that the color can be transferred between two images.

My implementation of color transfer is (loosely) based on Color Transfer between Images by Reinhard et al, 2001.

L A B COLOR CONVERTER INSTALL

You can also download the code via GitHub or install via PyPI (assuming that you already have OpenCV installed). Just simple statistics.Īnd by the way…this method can handle even gigantic images with ease. What if I told you that you could create a color transfer algorithm that uses nothing but the mean and standard deviation of the image channels. And while you can certainly speed the process up using a little NumPy magic you can do better. Using this algorithm would require you to perform a lookup for each and every pixel in the source image, which will become extremely expensive as the image grows in size. The approach obtained good results - but at the expense of speed. The authors’ implementation used a histogram based method, which aimed to balance between three “types” of bins: equal, excess, and deficit.

L A B COLOR CONVERTER HOW TO

No, this had to be a hand engineered algorithm that could take two arbitrary images, a source and a target, and then transfer the color space from the source image to the target image.Ī couple weeks ago I was browsing reddit and I came across a post on how to transfer colors between two images. Because I knew that as soon as I got back to the office, that my nose was going back on the grindstone.īack at home, I imported my photos to my laptop and thought, hey, there must be a way to take this picture of the beach that I took during the mid-morning and make it look like it was taken at dusk.Īnd since I’m a computer vision scientist, I certainly wasn’t going to resort to Photoshop. You know, something to remember the moment by. I then took out my iPhone and snapped a few photos of the ocean and clouds passing by. Click here to download the source code to this postĪbout a month ago, I spent a morning down at the beach, walking along the sand, letting the crisp, cold water lap against my feet.

L a b color converter