001/*******************************************************************************
002 * This software is provided as a supplement to the authors' textbooks on digital
003 * image processing published by Springer-Verlag in various languages and editions.
004 * Permission to use and distribute this software is granted under the BSD 2-Clause
005 * "Simplified" License (see http://opensource.org/licenses/BSD-2-Clause).
006 * Copyright (c) 2006-2023 Wilhelm Burger, Mark J. Burge. All rights reserved.
007 * Visit https://imagingbook.com for additional details.
008 ******************************************************************************/
009
010package imagingbook.common.threshold.global;
011
012import ij.process.ByteProcessor;
013import imagingbook.common.threshold.Thresholder;
014
015/**
016 * <p>
017 * Common interface to be implemented by all global thresholders. See Sec. 9.1 of [1] for an overview.
018 * </p>
019 * <p>
020 * [1] W. Burger, M.J. Burge, <em>Digital Image Processing &ndash; An Algorithmic Introduction</em>, 3rd ed, Springer
021 * (2022).
022 * </p>
023 *
024 * @author WB
025 * @version 2022/08/01
026 */
027public interface GlobalThresholder extends Thresholder {
028
029        public static final float NoThreshold = Float.NaN;
030
031        /**
032         * Returns a single (global) threshold value for the specified histogram.
033         *
034         * @param h a histogram (array of frequencies)
035         * @return a single (global) threshold value
036         */
037        public float getThreshold(int[] h);     // TODO: change return type to double?
038
039        /**
040         * Returns a single (global) threshold value for the specified {@link ByteProcessor} (8-bit image).
041         *
042         * @param bp a {@link ByteProcessor} (8-bit image)
043         * @return a single (global) threshold value
044         */
045        public default float getThreshold(ByteProcessor bp) {
046                int[] h = bp.getHistogram();
047                return getThreshold(h);
048        }
049        
050        @Override
051        public default boolean threshold(ByteProcessor ip) {
052                float q = getThreshold(ip);
053                if (q > 0) {
054                        ip.threshold(Math.round(q));
055                        return true;
056                }
057                else {
058                        return false;
059                }
060        }
061        
062}