/* * Copyright (C) 2011-2012 Dr. John Lindsay <jlindsay@uoguelph.ca> * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package plugins; import java.util.Date; import whitebox.geospatialfiles.WhiteboxRaster; import whitebox.interfaces.WhiteboxPlugin; import whitebox.interfaces.WhiteboxPluginHost; /** * This tool performs a percentage contrast stretch on a raster image, which maps each grid cell value in the input raster image (z) onto a new scale that ranges from a lower-tail clip value (L) to the upper-tail clip value (U), with the user-specified number of tonal values (n), such that: zn = (z - L) / (U - L) × n where zn is the output value. * @author Dr. John Lindsay email: jlindsay@uoguelph.ca */ public class PercentageContrastStretch implements WhiteboxPlugin { private WhiteboxPluginHost myHost = null; private String[] args; /** * Used to retrieve the plugin tool's name. This is a short, unique name containing no spaces. * @return String containing plugin name. */ @Override public String getName() { return "PercentageContrastStretch"; } /** * Used to retrieve the plugin tool's descriptive name. This can be a longer name (containing spaces) and is used in the interface to list the tool. * @return String containing the plugin descriptive name. */ @Override public String getDescriptiveName() { return "Percentage Contrast Stretch"; } /** * Used to retrieve a short description of what the plugin tool does. * @return String containing the plugin's description. */ @Override public String getToolDescription() { return "Performs a percentage linear contrast stretch on input images."; } /** * Used to identify which toolboxes this plugin tool should be listed in. * @return Array of Strings. */ @Override public String[] getToolbox() { String[] ret = { "ImageEnhancement" }; return ret; } /** * Used to communicate feedback pop-up messages between a plugin tool and the main Whitebox user-interface. * @param feedback String containing the text to display. */ private void showFeedback(String feedback) { if (myHost != null) { myHost.showFeedback(feedback); } else { System.out.println(feedback); } } /** * Used to communicate a return object from a plugin tool to the main Whitebox user-interface. * @return Object, such as an output WhiteboxRaster. */ private void returnData(Object ret) { if (myHost != null) { myHost.returnData(ret); } } /** * Used to communicate a progress update between a plugin tool and the main Whitebox user interface. * @param progressLabel A String to use for the progress label. * @param progress Float containing the progress value (between 0 and 100). */ private void updateProgress(String progressLabel, int progress) { if (myHost != null) { myHost.updateProgress(progressLabel, progress); } else { System.out.println(progressLabel + " " + progress + "%"); } } /** * Used to communicate a progress update between a plugin tool and the main Whitebox user interface. * @param progress Float containing the progress value (between 0 and 100). */ private void updateProgress(int progress) { if (myHost != null) { myHost.updateProgress(progress); } else { System.out.println("Progress: " + progress + "%"); } } /** * Sets the arguments (parameters) used by the plugin. * @param args An array of string arguments. */ @Override public void setArgs(String[] args) { this.args = args.clone(); } /** * Sets the WhiteboxPluginHost to which the plugin tool is tied. This is the class * that the plugin will send all feedback messages, progress updates, and return objects. * @param host The WhiteboxPluginHost that called the plugin tool. */ @Override public void setPluginHost(WhiteboxPluginHost host) { myHost = host; } private boolean cancelOp = false; /** * Used to communicate a cancel operation from the Whitebox GUI. * @param cancel Set to true if the plugin should be canceled. */ @Override public void setCancelOp(boolean cancel) { cancelOp = cancel; } private void cancelOperation() { showFeedback("Operation cancelled."); updateProgress("Progress: ", 0); } private boolean amIActive = false; /** * Used by the Whitebox GUI to tell if this plugin is still running. * @return a boolean describing whether or not the plugin is actively being used. */ @Override public boolean isActive() { return amIActive; } /** * Used to execute this plugin tool. */ @Override public void run() { amIActive = true; String inputFilesString = null; String[] imageHeaders = null; String outputHeader = null; String outputSuffix = null; int row, col; double z; double noData; int progress; int i, bin; int numImages = 0; double minVal, maxVal; int numBins = 1024; double clipPercentage = 1.0; String whichTailsToClip = "both"; if (args.length <= 0) { showFeedback("Plugin parameters have not been set."); return; } inputFilesString = args[0]; outputSuffix = " " + args[1].trim().replace(".dep", "") + ".dep"; clipPercentage = Double.parseDouble(args[2]); whichTailsToClip = args[3].toLowerCase(); numBins = Integer.parseInt(args[4]); // check to see that the inputHeader are not null. if ((inputFilesString == null) || (outputSuffix == null)) { showFeedback("One or more of the input parameters have not been set properly."); return; } try { imageHeaders = inputFilesString.split(";"); numImages = imageHeaders.length; for (i = 0; i < numImages; i++) { WhiteboxRaster image = new WhiteboxRaster(imageHeaders[i], "r"); int nRows = image.getNumberRows(); int nCols = image.getNumberColumns(); noData = image.getNoDataValue(); double[] data = null; // first create the histogram double inputImageMin = image.getMinimumValue(); double inputImageMax = image.getMaximumValue(); int inputImageBins = (int)(inputImageMax - inputImageMin + 1); double inputImageRange = inputImageMax - inputImageMin; double[] histo = new double[inputImageBins]; for (row = 0; row < nRows; row++) { data = image.getRowValues(row); for (col = 0; col < nCols; col++) { if (data[col] != noData) { bin = (int) (data[col] - inputImageMin); if (bin < 0) { bin = 0; } if (bin > (inputImageBins - 1)) { bin = (inputImageBins - 1); } histo[bin]++; } } if (cancelOp) { cancelOperation(); return; } progress = (int) (100f * row / (nRows - 1)); updateProgress("Calculating clip values:", progress); } // convert the histogram into a cumulative prob. for (int a = 1; a < inputImageBins; a++) { histo[a] = histo[a] + histo[a - 1]; } // convert the histogram into a cumulative prob. for (int a = 0; a < inputImageBins; a++) { histo[a] = histo[a] / histo[inputImageBins - 1] * 100; } // find the upper and lower tails. boolean lowerTailFound = false; boolean upperTailFound = false; minVal = -1; maxVal = -1; if (whichTailsToClip.contains("both")) { for (int a = 1; a < inputImageBins; a++) { if (histo[a] >= clipPercentage && !lowerTailFound) { minVal = (a - 1 + inputImageMin) + (clipPercentage - histo[a - 1]) / (histo[a] - histo[a - 1]); lowerTailFound = true; } if (histo[a] >= (100 - clipPercentage) && !upperTailFound) { maxVal = (a - 1 + inputImageMin) + ((100 - clipPercentage) - histo[a - 1]) / (histo[a] - histo[a - 1]); upperTailFound = true; break; } } } else if (whichTailsToClip.contains("lower")) { for (int a = 1; a < inputImageBins; a++) { if (histo[a] >= clipPercentage && !lowerTailFound) { minVal = (a - 1 + inputImageMin) + (clipPercentage - histo[a - 1]) / (histo[a] - histo[a - 1]); lowerTailFound = true; break; } } maxVal = inputImageMax; } else { for (int a = 1; a < inputImageBins; a++) { if (histo[a] >= (100 - clipPercentage) && !upperTailFound) { maxVal = (a - 1 + inputImageMin) + ((100 - clipPercentage) - histo[a - 1]) / (histo[a] - histo[a - 1]); upperTailFound = true; break; } } minVal = inputImageMin; } double scaleFactor = numBins / (maxVal - minVal); outputHeader = imageHeaders[i].replace(".dep", outputSuffix); WhiteboxRaster output = new WhiteboxRaster(outputHeader, "rw", imageHeaders[i], WhiteboxRaster.DataType.INTEGER, noData); output.setPreferredPalette(image.getPreferredPalette()); for (row = 0; row < nRows; row++) { data = image.getRowValues(row); for (col = 0; col < nCols; col++) { if (data[col] != noData) { z = (int) (data[col] - minVal) * scaleFactor; if (z < 0) { z = 0; } if (z > (numBins - 1)) { z = (numBins - 1); } output.setValue(row, col, z); } else { output.setValue(row, col, noData); } } if (cancelOp) { cancelOperation(); return; } progress = (int) (100f * row / (nRows - 1)); updateProgress("Loop " + (i + 1) + " of " + numImages + ":", progress); } image.close(); output.addMetadataEntry("Created by the " + getDescriptiveName() + " tool."); output.addMetadataEntry("Created on " + new Date()); output.close(); } // returning a header file string displays the image. returnData(outputHeader); } catch (OutOfMemoryError oe) { myHost.showFeedback("An out-of-memory error has occurred during operation."); } catch (Exception e) { myHost.showFeedback("An error has occurred during operation. See log file for details."); myHost.logException("Error in " + getDescriptiveName(), e); } finally { updateProgress("Progress: ", 0); // tells the main application that this process is completed. amIActive = false; myHost.pluginComplete(); } } // // this is only used for debugging the tool // public static void main(String[] args) { // PercentageContrastStretch pcs = new PercentageContrastStretch(); // args = new String[5]; // args[0] = "/Users/johnlindsay/Documents/Teaching/GEOG3420/Winter 2012/Labs/Lab5/Data/tm19920807_b1.dep;/Users/johnlindsay/Documents/Teaching/GEOG3420/Winter 2012/Labs/Lab5/Data/tm19920807_b1.dep;/Users/johnlindsay/Documents/Teaching/GEOG3420/Winter 2012/Labs/Lab5/Data/tm19920807_b3.dep"; // args[1] = "percentage stetched"; // args[2] = "2"; // args[3] = "upper"; // args[4] = "256"; // // pcs.setArgs(args); // pcs.run(); // // } }