Image processing 修改RGB图像亮度的算法?
我知道有RGB->亮度的公式,但我需要给定一个亮度参数来修改图像的RGB值。我该怎么做 谢谢从RGB映射到HSL(色调/饱和度/亮度),保持色调和饱和度相同,只需修改亮度,然后从HSL向后映射到RGBImage processing 修改RGB图像亮度的算法?,image-processing,rgb,Image Processing,Rgb,我知道有RGB->亮度的公式,但我需要给定一个亮度参数来修改图像的RGB值。我该怎么做 谢谢从RGB映射到HSL(色调/饱和度/亮度),保持色调和饱和度相同,只需修改亮度,然后从HSL向后映射到RGB 最简单的方法是将R、G、B值乘以某个常数-如果常数大于1,则会使其更亮,如果添加到Mark Ransom的答案中:最好将上述系数与255常数一起使用,并将其添加到当前颜色值中: float brightnessFac = //between -1.0 and 1.0 byte bright
最简单的方法是将R、G、B值乘以某个常数-如果常数大于1,则会使其更亮,如果添加到Mark Ransom的答案中:最好将上述系数与255常数一起使用,并将其添加到当前颜色值中:
float brightnessFac = //between -1.0 and 1.0
byte brightnessRed = red + (255f * brightnessFac);
如果你只使用一个介于0.0和1.0之间的因子
byte brightnessRed = red * brightnessFac;
值0保持为零。调整图像的亮度是可以完成的最简单的图像处理操作之一。所涉及的全部内容是为每个红色、绿色和蓝色组件添加所需的亮度变化 它会是这样的:
colour = GetPixelColour(x, y)
newRed = Truncate(Red(colour) + brightness)
newGreen = Truncate(Green(colour) + brightness)
newBlue = Truncate(Blue(colour) + brightness)
PutPixelColour(x, y) = RGB(newRed, newGreen, newBlue)
编码以确保红色、绿色和蓝色的新值在有效范围内。
Procedure Truncate(value)
If value < 0 Then value = 0
If value > 255 Then value = 255
Return value
EndProcedure
过程截断(值)
如果值<0,则值=0
如果值>255,则值=255
返回值
结束程序
我的建议与客户的答案相同,但有一点不同:
使用,因为它是一个近似的Photoshop的算法,有更好的结果
为了不只是链接到HSP的网站(坦白地说,这应该足够了;只是我不喜欢没有示例的回答),下面是我的
C
实现,它遵循了网站的:
#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);
}
#区域定义
//感知亮度与红色的比率。
私人常数双Pr=.299;
//感知亮度与绿色比率。
私人常数双Pg=.587;
//感知亮度与蓝色的比率。
私有常量双Pb=.114;
#端区
//预期范围:色调=0-359。。。其他值=0-1
公共静态颜色RGB ToRGB(双色调、双饱和度、双感知亮度、双alpha){
//检查预期范围内的值
色调=色调<0?0:色调>359?359:色调;
饱和度=饱和度<0?0:饱和度>1?1:饱和度;
感知亮度=感知亮度<0?0:感知亮度>1?1:感知亮度;
α=α<0?0:α>1?1:α;
//转化
var minOverMax=1-饱和;
双r,g,b;
如果(最小最大值>0){
两部分;
如果(色调<0.16667d){//R>G>B
色调=6*(色调-0);部分=1+色调*(1/最小值最大值-1);
b=感知亮度/数学Sqrt(Pr/minOverMax/minOverMax+Pg*零件*零件+Pb);
r=b/最小最大值;g=b+色调*(r-b);
}
else如果(色调<0.333d){//G>R>B
色调=6*(-hue+0.333d);部分=1+hue*(1/minOverMax-1);
b=感知亮度/数学Sqrt(Pg/minOverMax/minOverMax+Pr*零件*零件+Pb);
g=b/最小最大值;r=b+色调*(g-b);
}
如果(色调<0.5D){//G>B>R
色调=6*(色调-0.333D);部分=1+色调*(1/最小值最大值-1);
r=感知亮度/数学Sqrt(Pg/minOverMax/minOverMax+Pb*零件*零件+Pr);
g=r/minOverMax;b=r+hue*(g-r);
}
else如果(色调<0.6666667d){//B>G>R
色调=6*(-色调+0.6666667D);部分=1+色调*(1/最小值最大值-1);
r=感知亮度/数学Sqrt(Pb/minOverMax/minOverMax+Pg*零件*零件+Pr);
b=r/minOverMax;g=r+hue*(b-r);
}
else如果(色调<0.833333d){//B>R>G
色调=6*(色调-0.666666667D);部分=1+色调*(1/最小值最大值-1);
g=感知亮度/数学Sqrt(Pb/minOverMax/minOverMax+Pr*零件*零件+Pg);
b=g/minOverMax;r=g+hue*(b-g);
}
else{//R>B>G
色调=6*(-hue+1D);部分=1+hue*(1/minOverMax-1);
g=感知亮度/数学Sqrt(Pr/minOverMax/minOverMax+Pb*零件*零件+Pg);
r=g/minOverMax;b=g+hue*(r-g);
}
}
否则{
如果(色调<0.16667d){//R>G>B
色调=6*(色调-0D);r=Math.Sqrt(感知亮度*感知亮度/(Pr+Pg*色调*色调));g=r*色调;b=0;
}
else如果(色调<0.333d){//G>R>B
色调=6*(-hue+0.333d);g=Math.Sqrt(感知亮度*感知亮度/(Pg+Pr*色调*色调));r=g*色调;b=0;
}
如果(色调<0.5D){//G>B>R
色调=6*(色调-0.333d);g=Math.Sqrt(感知亮度*感知亮度/(Pg+Pb*色调*色调));b=g*色调;r=0;
}
else如果(色调<0.6666667d){//B>G>R
色调=6*(-hue+0.666666667d);b=Math.Sqrt(感知亮度*感知亮度/(Pb+Pg*色调*色调));g=b*色调;r=0;
}
else如果(色调<0.833333d){//B>R>G
色调=6*(色调-0.666666667d);b=Math.Sqrt(感知亮度*感知亮度/(Pb+Pr*色调*色调));r=b*色调;g=0;
}
else{//R>B>G
色调=6*(-hue+1D);r=Math.Sqrt(感知亮度*感知亮度/(Pr+Pb*色调*色调));b=r*色调;g=0;
}
}
返回新的颜色RGB(r、g、b、alpha);
}
//预期范围:所有组件上的0-1
RGB的公共静态颜色HSP(双红、双绿、双蓝、双阿尔法){
//保证RGB值在正确的范围内
红色=红色<0?0:红色>1?1:红色;
绿色=绿色<0?0:绿色>1?1:绿色;
蓝色=蓝色<0?0:蓝色>1?1:蓝色;
α=α<0?0:α>1?1:α;
//准备和cac
import java.io. * ;
import java.awt.Color;
import javax.imageio.ImageIO;
import java.io. * ;
import java.awt.image.BufferedImage;
class Psp {
public static void main(String a[]) {
try {
File input = new File("abc.jpg");
File output = new File("output1.jpg");
BufferedImage picture1 = ImageIO.read(input); // original
BufferedImage picture2 = new BufferedImage(picture1.getWidth(), picture1.getHeight(), BufferedImage.TYPE_INT_RGB);
int width = picture1.getWidth();
int height = picture1.getHeight();
int factor = 50;
for (int y = 0; y < height; y++) { //loops for images
for (int x = 0; x < width; x++) {
Color c = new Color(picture1.getRGB(x, y));
int r = c.getRed() + factor;
int b = c.getBlue() + factor;
int g = c.getGreen() + factor;
if (r >= 256) {
r = 255;
} else if (r < 0) {
r = 0;
}
if (g >= 256) {
g = 255;
} else if (g < 0) {
g = 0;
}
if (b >= 256) {
b = 255;
} else if (b < 0) {
b = 0;
}
picture2.setRGB(x, y, new Color(r, g, b).getRGB());
}
}
ImageIO.write(picture2, "jpg", output);
} catch(Exception e) {
System.out.println(e);
}
}
}