How to determine if a color is close to another color

Question

I am creating a kind of color tool and this tool should tell me if color is close to another color, For example:

Color[] colors = new colors[] { Color.FromArgb(0,0,255), Color.FromArgb(0,109,251)};
//colors[0] IS BLUE
//colors[1] IS BRIGHTER BLUE (#006DFB)
bool TheyClose = ColorsAreClose(colors[0],colors[1]); //TRUE BLUE IS CLOSE
//TheyColse Should Be = TURE

How should a ColorsAreClose() function Look?

Look up [HSV color space](http://en.wikipedia.org/wiki/HSL_and_HSV) and find if the are similar in hue, brightness and saturation. — John Alexiou, Aug 06 '14 at 19:21
Seeing all the (accepted) answers, I felt a comment was more helpful. https://en.wikipedia.org/wiki/Color_difference is the article about colour difference. Using CIELAB and the differences there, comes up with a more human-perception measure of difference — mksteve, Mar 14 '22 at 07:40

score 11 · Accepted Answer · edited Apr 22 '16 at 22:58

How about something like this?

bool ColorsAreClose(Color a, Color z, int threshold = 50)
{
    int r = (int)a.R - z.R,
        g = (int)a.G - z.G,
        b = (int)a.B - z.B;
    return (r*r + g*g + b*b) <= threshold*threshold;
}

(I just guessed at the default threshold, but you should set it to what you want.)

Basically this just computes, on average, whether the three color channels are close enough between the two colors.

score 6 · Answer 2 · edited Mar 08 '21 at 13:00

6

A simple way, measure RGB distance:

public bool ColorsAreClose(Color[] colors)
{

    var rDist = Math.Abs(colors[0].R - colors[1].R);
    var gDist = Math.Abs(colors[0].G - colors[1].G);
    var bDist = Math.Abs(colors[0].B - colors[1].B);

    if(rDist + gDist + bDist > Threshold)
        return false;

    return true;

}

Threshold is a constant with the maximum deviation you want to consider close.

edited Mar 08 '21 at 13:00

d219

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answered Aug 06 '14 at 19:23

Gusman

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Thank You :) i also found this: http://stackoverflow.com/questions/7846286/c-sharp-finding-similar-colors – Jhon Aug 06 '14 at 19:24

TaW · Answer 3 · 2018-08-22T20:06:24.593

2

You can calculate the 3-D color space distance as

Math.Sqrt(Math.Pow(c1.R-c2.R,2)+Math.Pow(c1.G-c2.g,2)+Math.Pow(c1.B-c2.b,2)));

or you can calculate the hue difference as

Math.Abs(c1.GetHue() - c2.GetHue());

A more thorough discussion can be found here.

edited Aug 22 '18 at 20:06

answered Aug 06 '14 at 20:44

TaW

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score 0 · Answer 4 · answered Aug 06 '14 at 19:24

This is somewhat subjective and not scientific, I used the following procedure on a project once.

public bool IsMatch(Color colorA, Color colorB)
{
    return IsMatch(colorA.Red, colorB.Red)
        && IsMatch(colorA.Green, colorB.Green)
        && IsMatch(colorA.Blue, colorB.Blue);
}

public bool IsMatch(double colorA, double colorB)
{
    var difference = colorA - colorB;
    return -5 < difference
        || difference < 5;
}

score 0 · Answer 5 · answered Aug 06 '14 at 19:24

0

If talking just about hue you could compare the difference in RGB values separately and if the total difference is under a set amount set by you then you could call them close.

answered Aug 06 '14 at 19:24

RustyH

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romanoza · Answer 6 · 2014-08-06T20:17:19.913

0

You can start with:

double delta = Math.Abs(c1.GetHue() - c2.GetHue());
if(delta > 180)
  delta = 360 - delta;
return delta <= threshold

For more info about the hue see: http://en.wikipedia.org/wiki/Hue

edited Aug 06 '14 at 20:17

answered Aug 06 '14 at 20:06

romanoza

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How to determine if a color is close to another color

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