org.openimaj.image.processing.threshold.AdaptiveLocalThresholdGaussian Maven / Gradle / Ivy
/**
* Copyright (c) 2011, The University of Southampton and the individual contributors.
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package org.openimaj.image.processing.threshold;
import org.openimaj.image.FImage;
import org.openimaj.image.processing.convolution.FGaussianConvolve;
import org.openimaj.image.processor.SinglebandImageProcessor;
/**
* Adaptive local thresholding using the Gaussian weighted sum of the patch and
* an offset.
*
* @author Jonathon Hare ([email protected])
*
*/
public class AdaptiveLocalThresholdGaussian implements SinglebandImageProcessor {
private float offset;
private float sigma;
/**
* Construct the thresholding operator with the given Gaussian standard
* deviation, sigma, and offset
*
* @param sigma
* Gaussian kernel standard deviation
* @param offset
* offset from the patch mean at which the threshold occurs
*/
public AdaptiveLocalThresholdGaussian(float sigma, float offset) {
this.sigma = sigma;
this.offset = offset;
}
@Override
public void processImage(FImage image) {
final FImage tmp = image.process(new FGaussianConvolve(sigma));
final float[][] tpix = tmp.pixels;
final float[][] ipix = image.pixels;
for (int y = 0; y < image.height; y++)
for (int x = 0; x < image.width; x++)
tpix[y][x] = ipix[y][x] < (tpix[y][x] - offset) ? 0f : 1f;
image.internalAssign(tmp);
}
}