修改RGB图像亮度的算法？
我知道有RGB的公式 - >亮度，但我需要一个亮度参数来修改图像的RGB值。 我怎么做？
谢谢
从RGB到HSL（色调/饱和度/亮度）的映射，保持色调和饱和度相同，只需修改亮度，然后执行从HSL到RGB的反向映射。
您可以在这里阅读有关RGB到HSL和HSL到RGB转换的更多信息。
最简单的方法是将每个R，G，B值乘以某个常数 - 如果常数大于1，则会使其更亮，如果<1，则会更暗。 如果你使它更亮，那么你必须测试每个值以确保它不超过最大值（通常为255）。
这不仅比从RGB到HSL的翻译更简单，而且更简单，但它更接近于当您在物理对象上照射不同光量时发生的情况。
我的建议与ChrisA的答案相同，只有一点不同：
使用HS P颜色空间，因为它是Photoshop算法的近似值，并且具有更好的结果。
为了不仅仅链接到HSP的站点（坦率地说应该足够了;只是我不喜欢没有示例的答案），下面是我的C#实现，它遵循以下站点：
#region Definitions
//Perceived brightness to Red ratio.
private const double Pr = .299;
//Perceived brightness to Green ratio.
private const double Pg = .587;
//Perceived brightness to Blue ratio.
private const double Pb = .114;
#endregion
//Expected ranges: Hue = 0-359... Other values = 0-1
public static ColorRGB ToRGB(double hue, double saturation, double perceivedBrightness, double alpha) {
//Check values within expected range
hue = hue < 0 ? 0 : hue > 359 ? 359 : hue;
saturation = saturation < 0 ? 0 : saturation > 1 ? 1 : saturation;
perceivedBrightness = perceivedBrightness < 0 ? 0 : perceivedBrightness > 1 ? 1 : perceivedBrightness;
alpha = alpha < 0 ? 0 : alpha > 1 ? 1 : alpha;
//Conversion
var minOverMax = 1 - saturation;
double r, g, b;
if (minOverMax > 0) {
double part;
if (hue < 0.166666666666667D) { //R>G>B
hue = 6 * (hue - 0); part = 1 + hue * (1 / minOverMax - 1);
b = perceivedBrightness / Math.Sqrt(Pr / minOverMax / minOverMax + Pg * part * part + Pb);
r = b / minOverMax; g = b + hue * (r - b);
}
else if (hue < 0.333333333333333D) { //G>R>B
hue = 6 * (-hue + 0.333333333333333D); part = 1 + hue * (1 / minOverMax - 1);
b = perceivedBrightness / Math.Sqrt(Pg / minOverMax / minOverMax + Pr * part * part + Pb);
g = b / minOverMax; r = b + hue * (g - b);
}
else if (hue < 0.5D) { // G>B>R
hue = 6 * (hue - 0.333333333333333D); part = 1 + hue * (1 / minOverMax - 1);
r = perceivedBrightness / Math.Sqrt(Pg / minOverMax / minOverMax + Pb * part * part + Pr);
g = r / minOverMax; b = r + hue * (g - r);
}
else if (hue < 0.666666666666667D) { //B>G>R
hue = 6 * (-hue + 0.666666666666667D); part = 1 + hue * (1 / minOverMax - 1);
r = perceivedBrightness / Math.Sqrt(Pb / minOverMax / minOverMax + Pg * part * part + Pr);
b = r / minOverMax; g = r + hue * (b - r);
}
else if (hue < 0.833333333333333D) { //B>R>G
hue = 6 * (hue - 0.666666666666667D); part = 1 + hue * (1 / minOverMax - 1);
g = perceivedBrightness / Math.Sqrt(Pb / minOverMax / minOverMax + Pr * part * part + Pg);
b = g / minOverMax; r = g + hue * (b - g);
}
else { //R>B>G
hue = 6 * (-hue + 1D); part = 1 + hue * (1 / minOverMax - 1);
g = perceivedBrightness / Math.Sqrt(Pr / minOverMax / minOverMax + Pb * part * part + Pg);
r = g / minOverMax; b = g + hue * (r - g);
}
}
else {
if (hue < 0.166666666666667D) { //R>G>B
hue = 6 * (hue - 0D); r = Math.Sqrt(perceivedBrightness * perceivedBrightness / (Pr + Pg * hue * hue)); g = r * hue; b = 0;
}
else if (hue < 0.333333333333333D) { //G>R>B
hue = 6 * (-hue + 0.333333333333333D); g = Math.Sqrt(perceivedBrightness * perceivedBrightness / (Pg + Pr * hue * hue)); r = g * hue; b = 0;
}
else if (hue < 0.5D) { //G>B>R
hue = 6 * (hue - 0.333333333333333D); g = Math.Sqrt(perceivedBrightness * perceivedBrightness / (Pg + Pb * hue * hue)); b = g * hue; r = 0;
}
else if (hue < 0.666666666666667D) { //B>G>R
hue = 6 * (-hue + 0.666666666666667D); b = Math.Sqrt(perceivedBrightness * perceivedBrightness / (Pb + Pg * hue * hue)); g = b * hue; r = 0;
}
else if (hue < 0.833333333333333D) { //B>R>G
hue = 6 * (hue - 0.666666666666667D); b = Math.Sqrt(perceivedBrightness * perceivedBrightness / (Pb + Pr * hue * hue)); r = b * hue; g = 0;
}
else { //R>B>G
hue = 6 * (-hue + 1D); r = Math.Sqrt(perceivedBrightness * perceivedBrightness / (Pr + Pb * hue * hue)); b = r * hue; g = 0;
}
}
return new ColorRGB(r, g, b, alpha);
}
//Expected ranges: 0-1 on all components
public static ColorHSP FromRGB(double red, double green, double blue, double alpha) {
//Guarantee RGB values are in the correct ranges
red = red < 0 ? 0 : red > 1 ? 1 : red;
green = green < 0 ? 0 : green > 1 ? 1 : green;
blue = blue < 0 ? 0 : blue > 1 ? 1 : blue;
alpha = alpha < 0 ? 0 : alpha > 1 ? 1 : alpha;
//Prepare & cache values for conversion
var max = MathExtensions.Max(red, green, blue);
var min = MathExtensions.Min(red, green, blue);
var delta = max - min;
double h, s, p = Math.Sqrt(0.299 * red + 0.587 * green + 0.114 * blue);
//Conversion
if (delta.Equals(0)) h = 0;
else if (max.Equals(red)) {
h = (green - blue) / delta % 6;
}
else if (max.Equals(green)) h = (blue - red) / delta + 2;
else h = (red - green) / delta + 4;
h *= 60;
if (h < 0) h += 360;
if (p.Equals(0))
s = 0;
else
s = delta / p;
//Result
return new ColorHSP(h, s, p, alpha);
}