Function Idea

[tielur]

What's your thoughts on adding function(s) to detect the color difference between two colors? My use case is that I have two images that I'm detecting the Image.dominant_color/1 and want to see see how similar those colors are

I was reading more about the math behind it here:
https://stackoverflow.com/questions/27374550/how-to-compare-color-object-and-get-closest-color-in-an-color/27375621#27375621

Feel free to close this if you don't think it fits this library and/or it's a crazy idea

[kipcole9]

Good suggestion and thanks for submitting it. I really dislike the lack of a proper colour model in Image - its on the to-do list to make a proper color library but apart from a myriad of ideas, there's no code yet. And of course color comparison would live in that lib. But for now, adding it to image works for me.

I am inclined to use 𝚫E (CIE 2000) for the difference calculation. Is that going to be ok for you? The function would be called Image.Color.delta_e(color, base_color).

Let me power up some coffee and see what I can come up with.

[tielur]

I'm definitely not a math guy but I was thinking basically like a Levenshtein distance for colors. What would be the output of that Image.Color.delta_e(color, base_color) function?

[kipcole9]

Tricky thing is that the mathematical difference isn't the same as the perceptual difference. Hence why there are different ways to look at "difference". I can implement a few different ways to compare so that's not an issue. Is there a particular use case you have in mind (beyond just wanting to know the difference)?

[tielur]

I plan on getting a base dominate color and then in the future I want to see if a new image matches that dominate color, but there may be "drift" in what the dominate color is. Which is why I was thinking if I could do some type of "Levenshtein distance" or whatever that would mean in color space it might work well

[tielur]

Basically a dumbed down version of classification I suppose based on the dominate color in an image

[kipcole9]

I'm going to use this as motivation to get color built as a library, including color comparisons. It will take a couple of weeks to get to a viable stage I think. Is that ok timing for you?

[tielur]

Timing works great! Can't wait to try it out!

[kipcole9]

You might find the code that uses color ranges in Image.chroma_mask/2 to be relevant. It deals with color ranges rather than color similarity but there is some overlap of intent.