Display temperature as a color with C#?

Question

Someone knows an algorithm that gets temperatue in Kelvin/Celsius and returns RGB?

Like in thermal cameras.

I found some links :

http://www.brucelind

Answer 1

I realize this is a two-year old thread, but I had the same predicament.

I took the data from the color table and did applied piece-wise 5th order polynomial fitting using Numpy.polyfit in Python. From those coefficients I was able to come up with the C# function below. R-squared values for the fits are close to or exceed 0.999. It has less than .01% error through most of its domain, but it does have a couple of points where it is closer to 3%. Should be good enough for most situations though.

private Color blackBodyColor(double temp)
{
    float x = (float)(temp / 1000.0);
    float x2 = x * x;
    float x3 = x2 * x;
    float x4 = x3 * x;
    float x5 = x4 * x;

    float R, G, B = 0f;

    // red
    if (temp <= 6600)
        R = 1f;
    else
        R = 0.0002889f * x5 - 0.01258f * x4 + 0.2148f * x3 - 1.776f * x2 + 6.907f * x - 8.723f;

    // green
    if (temp <= 6600)
        G = -4.593e-05f * x5 + 0.001424f * x4 - 0.01489f * x3 + 0.0498f * x2 + 0.1669f * x - 0.1653f;
    else
        G = -1.308e-07f * x5 + 1.745e-05f * x4 - 0.0009116f * x3 + 0.02348f * x2 - 0.3048f * x + 2.159f;

    // blue
    if (temp <= 2000f)
        B = 0f;
    else if (temp < 6600f)
        B = 1.764e-05f * x5 + 0.0003575f * x4 - 0.01554f * x3 + 0.1549f * x2 - 0.3682f * x + 0.2386f;
    else
        B = 1f;

    return Color.FromScRgb(1f, R, G, B);
}