CODEWITHSUNDEEP
c#image-processingcolorsrgbhsv
Visuddha Karunaratne
Visuddha Karunaratne

Reputation: 536

changing white and black color using HSV color space

im converting the the RGB color image into HSV color space and Im change hue using a trackbar and converting back it to RGB values. this methord works fine and changes color excepts for white and black pixels. why is that? 

 public static Color ColorFromHSV(double hue, double saturation, double value)
{
    int hi = Convert.ToInt32(Math.Floor(hue / 60)) % 6;
    double f = hue / 60 - Math.Floor(hue / 60);

    value = value * 255;
    int v = Convert.ToInt32(value);
    int p = Convert.ToInt32(value * (1 - saturation));
    int q = Convert.ToInt32(value * (1 - f * saturation));
    int t = Convert.ToInt32(value * (1 - (1 - f) * saturation));

    if (hi == 0)
        return Color.FromArgb(255, v, t, p);
    else if (hi == 1)
        return Color.FromArgb(255, q, v, p);
    else if (hi == 2)
        return Color.FromArgb(255, p, v, t);
    else if (hi == 3)
        return Color.FromArgb(255, p, q, v);
    else if (hi == 4)
        return Color.FromArgb(255, t, p, v);
    else
        return Color.FromArgb(255, v, p, q);
}

public void convertToHSV(Color color, out double hue, out double saturation, out double value)
        {
            int max = Math.Max(color.R, Math.Max(color.G, color.B));
            int min = Math.Min(color.R, Math.Min(color.G, color.B));

            hue = color.GetHue();
            saturation = (max == 0) ? 0 : 1d - (1d * min / max);
            value = max / 255d;

        }

Upvotes: 0

Views: 1977

Answers (1)

Peter O.
Peter O.

Reputation: 32898

It's because white, gray, and black have no hue, so they don't change if their hue is changed.

Upvotes: 3

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