RGB到CIELAB转换 [英] RGB to CIELAB conversion

问题描述

import java.awt.*;
import java.awt.image.*;
import java.io.*;
import javax.imageio.ImageIO;


public class ConvertRGBtoLAB {


    public static void main(String[] args) {

      //get input image
     String fileName = "IMG_7990.jpg";
     //read input image
     BufferedImage image = null;
        try
        {
            image = ImageIO.read(new File(fileName));
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }


        //setup result image
        int sizeX = image.getWidth();
        int sizeY = image.getHeight();


                float r, g, b, X, Y, Z, fx, fy, fz, xr, yr, zr;
  float ls, as, bs;
  float eps = 216.f/24389.f;
  float k = 24389.f/27.f;

  float Xr = 0.964221f;  // reference white D50
  float Yr = 1.0f;
  float Zr = 0.825211f;

                for (int y = 0; y < image.getHeight(); y++) {
            for (int x = 0; x < image.getWidth(); x++) {
                int c = image.getRGB(x,y);
                int  R= (c & 0x00ff0000) >> 16;
                int  G = (c & 0x0000ff00) >> 8;
                int  B = c & 0x000000ff;

                 r = R/255.f; //R 0..1
  g = G/255.f; //G 0..1
  b = B/255.f; //B 0..1

  // assuming sRGB (D65)
  if (r <= 0.04045)
   r = r/12;
  else
   r = (float) Math.pow((r+0.055)/1.055,2.4);

  if (g <= 0.04045)
   g = g/12;
  else
   g = (float) Math.pow((g+0.055)/1.055,2.4);

  if (b <= 0.04045)
   b = b/12;
  else
   b = (float) Math.pow((b+0.055)/1.055,2.4);


  X =  0.436052025f*r     + 0.385081593f*g + 0.143087414f *b;
  Y =  0.222491598f*r     + 0.71688606f *g + 0.060621486f *b;
  Z =  0.013929122f*r     + 0.097097002f*g + 0.71418547f  *b;

  // XYZ to Lab
  xr = X/Xr;
  yr = Y/Yr;
  zr = Z/Zr;

  if ( xr > eps )
   fx =  (float) Math.pow(xr, 1/3.);
  else
   fx = (float) ((k * xr + 16.) / 116.);

  if ( yr > eps )
   fy =  (float) Math.pow(yr, 1/3.);
  else
  fy = (float) ((k * yr + 16.) / 116.);

  if ( zr > eps )
   fz =  (float) Math.pow(zr, 1/3.);
  else
   fz = (float) ((k * zr + 16.) / 116);

  ls = ( 116 * fy ) - 16;
  as = 500*(fx-fy);
  bs = 200*(fy-fz);


                int Ls = (int) (2.55* ls + .5);
                int As = (int) (as + .5);
                int Bs = (int) (bs + .5);

               int lab = 0xFF000000 + (Ls << 16) + (As << 8) + Bs; // and reassign

                image.setRGB(x, y, lab);

          }
        }


        //write new image
         File outputfile = new File("lab.png");
         try {
         // png is an image format (like gif or jpg)
         ImageIO.write(image, "png", outputfile);
         } catch (IOException ex) {
         ex.printStackTrace();
         }


    }


}

您好，

我正在尝试将RGB图像转换为CIELAB色彩空间（LAB）我得到一个输出但我没有想法它应该是什么样子。

I am trying to turn a RGB image into CIELAB colour space(LAB) I get an output but I have no idea what it is supposed to look like.

有人能指出我已经存在的图像转换器或确认我已经正确完成了这个吗？

Can anyone point me to a already existing image converter or confirm that I have done this correctly?

谢谢！

推荐答案

我个人使用此网站作为常见颜色空间之间转换公式的快速参考。

I personally use this site as quick reference on conversion formulas between common color spaces.

这篇关于RGB到CIELAB转换的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！