boofcv.alg.tracker.meanshift.LikelihoodHistCoupled_SB_U8 Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of recognition Show documentation

BoofCV is an open source Java library for real-time computer vision and robotics applications.

There is a newer version: 0.26

/*
 * Copyright (c) 2011-2016, Peter Abeles. All Rights Reserved.
 *
 * This file is part of BoofCV (http://boofcv.org).
 *
 * Licensed 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 boofcv.alg.tracker.meanshift;

import boofcv.struct.image.GrayU8;
import georegression.struct.shapes.RectangleLength2D_I32;

/**
 * 
 * Creates a histogram in a gray scale image which is then used to compute the likelihood of a color being a
 * member of the original distribution based on its frequency.
 * 
 *
 * 
 * Design Note:

 * The reason operations in {@link boofcv.alg.feature.color.GHistogramFeatureOps} is not used internally is because
 * those are for histograms stored in double arrays, while this has to use floats/
 * 
 * @author Peter Abeles
 */
public class LikelihoodHistCoupled_SB_U8 implements PixelLikelihood
{
	GrayU8 image;

	// maximum value a pixel can have.
	int maxPixelValue;
	// Number of bins for each channel in the histogram
	int numBins;
	float hist[] = new float[0];

	public LikelihoodHistCoupled_SB_U8(int maxPixelValue, int numBins) {
		this.maxPixelValue = maxPixelValue+1;
		this.numBins = numBins;
	}

	@Override
	public void setImage(GrayU8 image) {
		this.image = image;

		if( hist.length != numBins ) {
			hist = new float[numBins];
		}
	}

	@Override
	public boolean isInBounds(int x, int y) {
		return image.isInBounds(x,y);
	}

	@Override
	public void createModel(RectangleLength2D_I32 target) {
		for( int y = 0; y < target.height; y++ ) {

			int index = image.startIndex + (y+target.y0)*image.stride + target.x0;
			for( int x = 0; x < target.width; x++ , index++ ) {
				int value = image.data[index] & 0xFF;
				int bin = numBins*value/maxPixelValue;
				hist[bin]++;
			}
		}

		float total = target.width*target.height;
		for( int i = 0; i < hist.length; i++ ) {
			hist[i] /= total;
		}
	}

	@Override
	public float compute(int x, int y) {
		int index = image.startIndex + y*image.stride + x;
		int value = image.data[index] & 0xFF;
		int bin = numBins*value/maxPixelValue;
		return hist[bin];
	}
}