[英]Using ImageIO to write JPEG 2000 with layers (i.e. decomposition levels)
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。 我们总是会看到.jpf文件,但它们通常没有指定的图层数或缩放比例。
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);
这是一个奇怪的经历,因为同一代码在后续运行中的行为有所不同。 任何见解将不胜感激!
是否所有TIFF文件都具有相同的设置(颜色模型)? 当使用索引颜色或多像素打包的源图像作为输入时, J2KImageWriter.java显示分解级别被设置为(强制)为零。
Drew处在正确的轨道上,下面的代码最终为我们整理了一些东西:
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();
}
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