Home/ Questions/Q 6139451
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-23T17:59:30+00:00

I am now looking for a lib that can change the color effect. Though

  • 0

I am now looking for a lib that can change the color effect.
Though the popular image processing lib such as opencv can do sufficient color transformation,
the details of the transformation matrix of a certain style remain unavailable to me.

So is there any book or lib that introduces how to apply a certain effect such as ones in lomography?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    From the comments it seems you would like to replicate “step by step” the Photoshop tutorial pointed by @0x69.

    With Mathematica 8, I did the following:

    Step1. I copied the picture from the tutorial

    enter image description here

    Step2. Define the point-based function that will change the red channel and apply it

    redfun[x_, s_] := 1/(1 + E^(-((x - 0.5)/s)));
Plot[{t, redfun[t, .1]}, {t, 0, 1}, AspectRatio -> 1]
img2 = ImageApply[{redfun[#[[1]], .1], #[[2]], #[[3]]} &, img]

    enter image description here

    Step3. I don’t know the algorithm used for color balancing by Photoshop, so let’s skip those and create directly a vignette. The color balancing would change things quite a bit.

    Step4. Vignette creation:

    vignette = ColorNegate@ImageAdjust[
               DistanceTransform[Image[1 - BoxMatrix[1, Reverse@ImageDimensions@img2]]],
               {0, 0, 2}, {Automatic, Automatic}]

    enter image description here

    You can just multiply the two images, or use fancier overlaying modes (see the documentation of ImageCompose):

    ImageMultiply[img2, vignette]

    enter image description here

    It would be quick and easy to tweak things around and change the final result.

    • 0