java - 替代 java.awt.imageproducer for android

Question

我正在尝试使用 stackoverflow 上的指南实现一些 ocr。使用该应用程序的示例代码正在使用 java，我正在尝试在 android 上运行它。这是示例中的代码；

    // OCRScannerDemo.java
// Copyright (c) 2003-2009 Ronald B. Cemer
// All rights reserved.
/*
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, version 2 of the License.

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 com.roncemer.ocr.main;

import java.awt.Frame;
import java.awt.Image;
import java.awt.MediaTracker;
import java.awt.ScrollPane;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.image.ImageProducer;
import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashMap;

import com.roncemer.ocr.CharacterRange;
import com.roncemer.ocr.OCRImageCanvas;
import com.roncemer.ocr.OCRScanner;
import com.roncemer.ocr.PixelImage;
import com.roncemer.ocr.TrainingImageLoader;
import com.roncemer.ocr.tracker.MediaTrackerProxy;

/**
  * Demo application to demonstrate OCR document scanning and decoding.
  * @author Ronald B. Cemer
  */
public class OCRScannerDemo extends Frame {

    private static final long serialVersionUID = -8030499184564680363L;

    private boolean debug = true;

    private Image image;
    private OCRImageCanvas imageCanvas;
    private OCRScanner scanner;

    public OCRScannerDemo() {
        super("OCR from a scanned image");
        setSize(1024, 768);
        ScrollPane scrollPane = new ScrollPane();
        imageCanvas = new OCRImageCanvas();
        scrollPane.add(imageCanvas);
        add(scrollPane);
        addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                ((Frame)(e.getSource())).hide();
                System.exit(0);
            }
        });
        scanner = new OCRScanner();
        show();
    }

    /**
      * Load demo training images.
      * @param trainingImageDir The directory from which to load the images.
      */
    public void loadTrainingImages(String trainingImageDir) {
        if (debug) System.err.println("loadTrainingImages(" + trainingImageDir + ")");
        if (!trainingImageDir.endsWith(File.separator)) {
            trainingImageDir += File.separator;
        }
        try {
            scanner.clearTrainingImages();
            TrainingImageLoader loader = new TrainingImageLoader();
            HashMap images = new HashMap();
            if (debug) System.err.println("ascii.png");
            loader.load(
                this,
                trainingImageDir + "ascii.png",
                new CharacterRange('!', '~'),
                images);
            if (debug) System.err.println("hpljPica.jpg");
            loader.load(
                this,
                trainingImageDir + "hpljPica.jpg",
                new CharacterRange('!', '~'),
                images);
            if (debug) System.err.println("digits.jpg");
            loader.load(
                this,
                trainingImageDir + "digits.jpg",
                new CharacterRange('0', '9'),
                images);
            if (debug) System.err.println("adding images");
            scanner.addTrainingImages(images);
            if (debug) System.err.println("loadTrainingImages() done");
        }
        catch(IOException ex) {
            ex.printStackTrace();
            System.exit(2);
        }
    }

    public void process(String imageFilename) {
        if (debug) System.err.println("process(" + imageFilename + ")");
        String imageFileUrlString = "";
        try {
            imageFileUrlString = new File(imageFilename).toURL().toString();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
        try {
            ImageProducer imageProducer = (ImageProducer)
                (new URL(imageFileUrlString).getContent());
            image = createImage(imageProducer);
        }
        catch(IOException e) {
            e.printStackTrace();
        }
        if (image == null) {
            System.err.println("Cannot find image file at " + imageFileUrlString);
            return;
        }
        MediaTracker mt = new MediaTrackerProxy(this);
        mt.addImage(image, 0);
        try {
            mt.waitForAll();
        } catch(InterruptedException ex) {}
        if (debug) System.err.println("image loaded");

/*  int w = image.getWidth(null);
    int h = image.getHeight(null);
    if ( (w > 0) && (h > 0) ) {
        float scaleFactor = 2048.0f/(float)Math.max(w, h);
        if (scaleFactor < 1.0f) {
        image = image.getScaledInstance(
            (int)((float)w*scaleFactor),
            (int)((float)h*scaleFactor), Image.SCALE_SMOOTH);
        mt = new MediaTrackerProxy(this);
        mt.addImage(image, 0);
        try { mt.waitForAll(); } catch(InterruptedException ex) {}
        }
    }*/

        imageCanvas.setSize(image.getWidth(null), image.getHeight(null));

        if (debug) System.err.println("constructing new PixelImage");
        PixelImage pixelImage = new PixelImage(image);
        if (debug) System.err.println("converting PixelImage to grayScale");
        pixelImage.toGrayScale(true);
        if (debug) System.err.println("filtering");
        pixelImage.filter();
        if (debug) System.err.println("setting image for display");
        imageCanvas.setImage(
            pixelImage.rgbToImage(
                pixelImage.grayScaleToRGB(pixelImage.pixels),
                pixelImage.width,
                pixelImage.height,
                imageCanvas));
        System.out.println(imageFilename + ":");
        String text = scanner.scan(image, 0, 0, 0, 0, null, imageCanvas.getGraphics());
        System.out.println("[" + text + "]");
    }

    public static void main(String[]args) {
        if (args.length < 1) {
            System.err.println("Please specify one or more image filenames.");
            System.exit(1);
        }
        String trainingImageDir = System.getProperty("TRAINING_IMAGE_DIR");
        if (trainingImageDir == null) {
            System.err.println
                ("Please specify -DTRAINING_IMAGE_DIR=<dir> on " +
                 "the java command line.");
            return;
        }
        OCRScannerDemo demo = new OCRScannerDemo();
        demo.loadTrainingImages(trainingImageDir);
        for (int i = 0; i < args.length; i++)
            demo.process(args[i]);
        System.out.println("done.");
    }
}

在处理方法中使用了 ImageProducer。是否有 android 的替代方案，或者我是否可以放弃使用这种方法？

亲切的问候

Answer 1

回复有点晚，但我想这可能对读者有帮助。

在 Android 上，将 android.graphics.Bitmap 类视为构建图像的入口点。与 Java AWT API 相比，它是创建和使用图像的直接简化。 Android 的 Bitmap 类与 java.awt.BufferedImage 非常相似，一个具有 set/getPixel 方法，另一个具有 set/getRGB 方法，以及一些从不同来源创建位图(图像)的方法。