org.apache.commons.imaging.formats.tiff.photometricinterpreters.PhotometricInterpreterLogLuv Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of commons-imaging Show documentation
Show all versions of commons-imaging Show documentation
Apache Commons Imaging (previously Sanselan) is a pure-Java image library.
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.imaging.formats.tiff.photometricinterpreters;
import java.io.IOException;
import org.apache.commons.imaging.ImageReadException;
import org.apache.commons.imaging.common.ImageBuilder;
/**
* Photometric interpretation Logluv support. Logluv is an encoding for storing
* data inside TIFF images.
*
* @see Logluv TIFF
*/
public class PhotometricInterpreterLogLuv extends PhotometricInterpreter {
/**
* Tristimulus color values (red-green-blue, as X-Y-Z, in the CIE XYZ color space).
*/
static class TristimulusValues {
public float x;
public float y;
public float z;
}
/**
* Rgb values (reg-green-blue, as R-G-B, as in the RGB color model).
*/
static class RgbValues {
public int r;
public int g;
public int b;
}
public PhotometricInterpreterLogLuv(final int samplesPerPixel,
final int[] bitsPerSample, final int predictor, final int width, final int height) {
super(samplesPerPixel, bitsPerSample, predictor, width, height);
}
@Override
public void interpretPixel(final ImageBuilder imageBuilder, final int[] samples, final int x,
final int y) throws ImageReadException, IOException {
if (samples == null || samples.length != 3) {
throw new ImageReadException("Invalid length of bits per sample (expected 3).");
}
// CIE illuminants. An illuminant is a theorical source of visible light with a profile.
// CIE stands for Commission Internationale de l'Eclairage, or International
// Comission on Illumination.
final int cieL = samples[0];
final int cieA = (byte) samples[1];
final int cieB = (byte) samples[2];
final TristimulusValues tristimulusValues = getTristimulusValues(cieL, cieA, cieB);
// ref_X = 95.047 //Observer = 2°, Illuminant = D65
// ref_Y = 100.000
// ref_Z = 108.883
final RgbValues rgbValues = getRgbValues(tristimulusValues);
// float R = 1.910f * X - 0.532f * Y - 0.288f * Z;
// float G = -0.985f * X + 1.999f * Y - 0.028f * Z;
// float B = 0.058f * X - 0.118f * Y + 0.898f * Z;
final int red = Math.min(255, Math.max(0, rgbValues.r));
final int green = Math.min(255, Math.max(0, rgbValues.g));
final int blue = Math.min(255, Math.max(0, rgbValues.b));
final int alpha = 0xff;
final int rgb = (alpha << 24) | (red << 16) | (green << 8) | (blue << 0);
imageBuilder.setRGB(x, y, rgb);
}
/**
* Receives a triplet of CIELAB values, and calculates the tristimulus values.
* The reference white point used here is the equivalent to summer sun and sky.
*
* @param cieL lightness from black to white
* @param cieA lightness from green to red
* @param cieB lightness from blue to yellow
* @return tristimulus (X, Y, and Z) values
* @see CIELAB color space
* @see White point
*/
TristimulusValues getTristimulusValues(final int cieL, final int cieA, final int cieB) {
float var_Y = ((cieL * 100.0f / 255.0f) + 16.0f) / 116.0f;
float var_X = cieA / 500.0f + var_Y;
float var_Z = var_Y - cieB / 200.0f;
final float var_x_cube = (float) Math.pow(var_X, 3.0d);
final float var_y_cube = (float) Math.pow(var_Y, 3.0d);
final float var_z_cube = (float) Math.pow(var_Z, 3.0d);
if (var_y_cube > 0.008856f) {
var_Y = var_y_cube;
} else {
var_Y = (var_Y - 16 / 116.0f) / 7.787f;
}
if (var_x_cube > 0.008856f) {
var_X = var_x_cube;
} else {
var_X = (var_X - 16 / 116.0f) / 7.787f;
}
if (var_z_cube > 0.008856f) {
var_Z = var_z_cube;
} else {
var_Z = (var_Z - 16 / 116.0f) / 7.787f;
}
// These reference values are the relative white points (XYZ) for commons scene types.
// The chosen values here reflect a scene with Summer Sun and Sky, temperature of 6504 K,
// X 95.047, Y 100.0, and Z 108.883.
// See Color Science by Wyszecki and Stiles for more
final float ref_X = 95.047f;
final float ref_Y = 100.000f;
final float ref_Z = 108.883f;
final TristimulusValues values = new TristimulusValues();
values.x = ref_X * var_X; // ref_X = 95.047 Observer= 2°, Illuminant= D65
values.y = ref_Y * var_Y; // ref_Y = 100.000
values.z = ref_Z * var_Z; // ref_Z = 108.883
return values;
}
/**
* Receives a triplet tristimulus values (CIE XYZ) and then does a CIELAB-CIEXYZ
* conversion (consult Wikipedia link for formula), where the CIELAB values are
* used to calculate the tristimulus values of the reference white point.
*
* @param tristimulusValues the XYZ tristimulus values
* @return RGB values
* @see CIELAB color space
*/
RgbValues getRgbValues(final TristimulusValues tristimulusValues) {
final float var_X = tristimulusValues.x / 100f; // X = From 0 to ref_X
final float var_Y = tristimulusValues.y / 100f; // Y = From 0 to ref_Y
final float var_Z = tristimulusValues.z / 100f; // Z = From 0 to ref_Y
float var_R = var_X * 3.2406f + var_Y * -1.5372f + var_Z * -0.4986f;
float var_G = var_X * -0.9689f + var_Y * 1.8758f + var_Z * 0.0415f;
float var_B = var_X * 0.0557f + var_Y * -0.2040f + var_Z * 1.0570f;
if (var_R > 0.0031308) {
var_R = 1.055f * (float) Math.pow(var_R, (1 / 2.4)) - 0.055f;
} else {
var_R = 12.92f * var_R;
}
if (var_G > 0.0031308) {
var_G = 1.055f * (float) Math.pow(var_G, (1 / 2.4)) - 0.055f;
} else {
var_G = 12.92f * var_G;
}
if (var_B > 0.0031308) {
var_B = 1.055f * (float) Math.pow(var_B, (1 / 2.4)) - 0.055f;
} else {
var_B = 12.92f * var_B;
}
// var_R = ((var_R + 0.16561039f) / (3.0152583f + 0.16561039f));
// var_G = ((var_G + 0.06561642f) / (3.0239854f + 0.06561642f));
// var_B = ((var_B + 0.19393992f) / (3.1043448f + 0.19393992f));
final RgbValues values = new RgbValues();
values.r = (int) (var_R * 255f);
values.g = (int) (var_G * 255f);
values.b = (int) (var_B * 255f);
return values;
}
}