1 /* 2 * Copyright (C) 2012 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 // Extract histogram from image. 18 19 package androidx.media.filterpacks.colorspace; 20 21 import androidx.media.filterfw.FrameValue; 22 23 import androidx.media.filterfw.Filter; 24 import androidx.media.filterfw.Frame; 25 import androidx.media.filterfw.FrameBuffer2D; 26 import androidx.media.filterfw.FrameType; 27 import androidx.media.filterfw.MffContext; 28 import androidx.media.filterfw.OutputPort; 29 import androidx.media.filterfw.Signature; 30 31 import java.nio.ByteBuffer; 32 import java.nio.ByteOrder; 33 import java.nio.FloatBuffer; 34 35 /** 36 * ColorfulnessFilter takes in a particular Chroma histogram generated by NewChromaHistogramFilter 37 * and compute the colorfulness based on the entropy in Hue space. 38 */ 39 public final class ColorfulnessFilter extends Filter { 40 41 public ColorfulnessFilter(MffContext context, String name) { 42 super(context, name); 43 } 44 45 @Override 46 public Signature getSignature() { 47 FrameType dataIn = FrameType.buffer2D(FrameType.ELEMENT_FLOAT32); 48 return new Signature() 49 .addInputPort("histogram", Signature.PORT_REQUIRED, dataIn) 50 .addOutputPort("score", Signature.PORT_REQUIRED, FrameType.single(float.class)) 51 .disallowOtherPorts(); 52 } 53 54 @Override 55 protected void onProcess() { 56 FrameBuffer2D histogramFrame = 57 getConnectedInputPort("histogram").pullFrame().asFrameBuffer2D(); 58 ByteBuffer byteBuffer = histogramFrame.lockBytes(Frame.MODE_READ); 59 byteBuffer.order(ByteOrder.nativeOrder()); 60 FloatBuffer histogramBuffer = byteBuffer.asFloatBuffer(); 61 histogramBuffer.rewind(); 62 63 // Create a hue histogram from hue-saturation histogram 64 int hueBins = histogramFrame.getWidth(); 65 int saturationBins = histogramFrame.getHeight() - 1; 66 float[] hueHistogram = new float[hueBins]; 67 float total = 0; 68 for (int r = 0; r < saturationBins; ++r) { 69 float weight = (float) Math.pow(2, r); 70 for (int c = 0; c < hueBins; c++) { 71 float value = histogramBuffer.get() * weight; 72 hueHistogram[c] += value; 73 total += value; 74 } 75 } 76 float colorful = 0f; 77 for (int c = 0; c < hueBins; ++c) { 78 float value = hueHistogram[c] / total; 79 if (value > 0f) { 80 colorful -= value * ((float) Math.log(value)); 81 } 82 } 83 84 colorful /= Math.log(2); 85 86 histogramFrame.unlock(); 87 OutputPort outPort = getConnectedOutputPort("score"); 88 FrameValue frameValue = outPort.fetchAvailableFrame(null).asFrameValue(); 89 frameValue.setValue(colorful); 90 outPort.pushFrame(frameValue); 91 } 92 93 } 94
