使用 ImageIO 编写带有层的 JPEG 2000（即分解级别）答案

【问题标题】：Using ImageIO to write JPEG 2000 with layers (i.e. decomposition levels)使用 ImageIO 编写带有层的 JPEG 2000（即分解级别）
【发布时间】：2013-07-27 03:35:40
【问题描述】：

好的，这是我们的问题：

我们正在尝试使用 imageio 将一系列黑白 .tiff 文件转换为 jpeg2000 .jpf 文件。我们总是获得可查看的 .jpf 文件，但它们通常没有指定的层数或用于缩放的分解级别。

这是我们的代码：

 //Get the tiff reader
 Iterator<ImageReader> readerIterator = ImageIO.getImageReadersByFormatName("tiff");
 ImageReader tiffreader = readerIterator.next();

 //make an ImageInputStream from our tiff file and have the tiff reader read it
 ImageInputStream iis = ImageIO.createImageInputStream(itemFile);

 tiffreader.setInput(iis);

 //just pass empty params to the tiff reader
 ImageReadParam tparam;
 tparam = new TIFFImageReadParam();

 IIOImage img = tiffreader.readAll(0, tparam);


 //set up target file
 File f = new File(itemTargetDirectory.getAbsolutePath() + "/" + destFileName);

 //we have tried FILTER_97 as well as different ProgressionTypes and compression settings
 J2KImageWriteParam param;
 param = new J2KImageWriteParam();
 param.setProgressionType("layer");
 param.setFilter(J2KImageWriteParam.FILTER_53);
 //Our problem is that this param is not always respected in the resulting .jpf
 param.setNumDecompositionLevels(5);

 //get the JPEG 2000 writer                             
 Iterator<ImageWriter> writerIterator = ImageIO.getImageWritersByFormatName("JPEG 2000");
 J2KImageWriter jp2kwriter = null;
 jp2kwriter = (J2KImageWriter) writerIterator.next();

 //write the jpf file
 ImageOutputStream ios = ImageIO.createImageOutputStream(f);
 jp2kwriter.setOutput(ios);
 jp2kwriter.write(null, img, param);

这是一种奇怪的体验，因为相同的代码在随后的运行中表现不同。任何见解将不胜感激！

【问题讨论】：

有多少读者返回 ImageIO.getImageReadersByFormatName("tiff");方法？有多少作者返回 ImageIO.getImageWritersByFormatName("JPEG 2000");方法？您是否有可能为每次执行获得不同的读者或作家？
@Fedy2 ImageIO 返回的读取器/写入器的顺序应该是稳定的。不过，最好确认一下是否确实如此。
任何地方的示例文件？
//我们的问题是这个参数（numDecompositionLevels）在生成的.jpf中并不总是得到尊重。当不考虑分解级别 5 时，您在生成的图像中获得了多少级别？

标签： java javax.imageio jpeg2000

【解决方案1】：

所有 TIFF 文件是否都具有相同的设置（颜色模型）？ J2KImageWriter.java 显示当索引颜色或多像素打包源图像用作输入时，分解级别设置（强制）为零。

【讨论】：

【解决方案2】：

Drew 走在了正确的轨道上，下面是最终为我们解决问题的代码：

 public void compressor(String inputFile, String outputFile) throws IOException {
    J2KImageWriteParam iwp = new J2KImageWriteParam();
    FileInputStream fis = new FileInputStream(new File(inputFile));
    BufferedImage image = ImageIO.read(fis);
    fis.close();

    if (image == null) 
    {
        System.out.println("If no registered ImageReader claims to be able to read the resulting stream");
    }

    Iterator writers = ImageIO.getImageWritersByFormatName("JPEG2000");
    String name = null;
    ImageWriter writer = null;
    while (name != "com.sun.media.imageioimpl.plugins.jpeg2000.J2KImageWriter") {
        writer = (ImageWriter) writers.next();
        name = writer.getClass().getName();
        System.out.println(name);
    }
    File f = new File(outputFile);
    long s = System.currentTimeMillis();
    ImageOutputStream ios = ImageIO.createImageOutputStream(f);
    writer.setOutput(ios);
    J2KImageWriteParam param = (J2KImageWriteParam) writer.getDefaultWriteParam();
    IIOImage ioimage = new IIOImage(image, null, null);
    param.setSOP(true);
    param.setWriteCodeStreamOnly(true);
    param.setProgressionType("layer");
    param.setLossless(false);
    param.setCompressionMode(J2KImageWriteParam.MODE_EXPLICIT);
    param.setCompressionType("JPEG2000");
    param.setCompressionQuality(0.1f);
    param.setEncodingRate(1.01);
    param.setFilter(J2KImageWriteParam.FILTER_97);


    writer.write(null, ioimage, param);
    System.out.println(System.currentTimeMillis() - s);
    writer.dispose();
    ios.flush();
    ios.close();

    image.flush();
}

【讨论】：