java - 如何使用 Java 在 ImageJ2 中将图像从 8 位转换为 RGB

Question

我尝试直接从 Java 使用 ImageJ2 创建来自输入图像的二值化图像。

我的代码的一些工作版本如下所示:

final File file = new File("input.png");

try {
    DefaultDataTypeService dataTypeService = new DefaultDataTypeService();
    Dataset dataset = imageJ.dataset().open(file.getAbsolutePath());
    Img inputImg = dataset.getImgPlus();

    PluginInfo pluginInfo = imageJ.plugin().getPlugin(Binarize.class);
    Binarize binarizeOp = (Binarize) pluginInfo.createInstance();
    binarizeOp.setContext(imageJ.getContext());
    binarizeOp.setChangeInput(true);
    binarizeOp.setFillMaskBackground(true);
    binarizeOp.setFillMaskForeground(true);
    binarizeOp.setInputData(dataset);
    binarizeOp.setInputMask(null);
    binarizeOp.setMaskColor(Binarize.WHITE);
    binarizeOp.setMaskPixels(Binarize.INSIDE);
    binarizeOp.setThresholdEachPlane(false);
    binarizeOp.setDefaultThresholdMethod();
    binarizeOp.run();

    dataset.rgbChange();
    DefaultDatasetService defaultDatasetService = new DefaultDatasetService();
    Img outputImg = dataset.getImgPlus();
    outputImg = outputImg.factory().imgFactory(new UnsignedByteType()).create(outputImg,new UnsignedByteType());
    Dataset outputDataset = defaultDatasetService.create(outputImg);
    imageJ.dataset().save(outputDataset,"input_binary.png");

} catch (IOException e) {
    e.printStackTrace();
} catch (InstantiableException e) {
    e.printStackTrace();
} catch (IncompatibleTypeException e) {
    e.printStackTrace();
}

运行此代码时，我遇到的问题是“input_binary.png”将完全变黑，我可以使用 ImageJ 客户端应用程序重现该行为。

我需要在客户端中将图像类型从“8位颜色”更改为“RGB颜色”。但我不知道如何使用当前版本的 net.imagej 库在 Java 中重现该内容。

我知道可以使用 1.x 库，但我想使用 2.x。

任何帮助将不胜感激。

Answer 1

由于以下原因，您会得到黑色图像:

outputImg = outputImg.factory().imgFactory(new UnsignedByteType()).create(outputImg,new UnsignedByteType());

这只是 copying the dimensionality源图像的值，而不是其值。

其他一些要点:

• 最佳实践是从上下文派生上下文对象(例如服务)，而不是手动构建。
• 二值化命令具有数据集输出，因此无需转到数据集 > ImgPlus > 数据集
• 如果您确实想要写出数据集，则需要将 Binarize 输出的 BitType 转换为支持的类型。

请参阅下面的运行 Binarize、获取输出、转换输出并将其写出的示例。希望有帮助!

public static void main(String... args) {
    final File file = new File("inpath.png");
    final File out = new File("outpath.png");

    // This is just sugar for the point of illustration.
    // The purpose here is just to have access to a Context
    ImageJ imagej = new ImageJ();

    // Cache the context for future use.
    Context context = imagej.getContext();

    try {
        // Use the context to get the services we want to ensure they are all
        // properly initialized.
        // If this was a Command these could all be @Parameters to be populated
        // automatically.
        DatasetService datasetService = context.getService(DatasetService.class);
        CommandService commandService = context.getService(CommandService.class);
        DatasetIOService datasetIOService =
            context.getService(DatasetIOService.class);

        Dataset input = datasetIOService.open(file.getAbsolutePath());

        // Start the command
        Future<CommandModule> future =
            commandService.run(Binarize.class, true, "inputData", input);

        // Get the command output
        Dataset binarized = (Dataset) future.get().getOutput("outputMask");

        // The output type is a binary image which, at the moment, needs to be
        // explicitly converted to something that can be written out.
        // Adapted from:
        // http://fiji.sc/ImgLib2_Examples#Example_2c_-_Generic_copying_of_image_data
        Img inputImg = input.getImgPlus().getImg();
        Img outputImg = binarized.getImgPlus().getImg();
        Img typedImg =
            inputImg.factory().create(inputImg, inputImg.firstElement());
        scale(outputImg, typedImg);

        Dataset output = datasetService.create(typedImg);

        // Save the output dataset
        datasetIOService.save(output, out.getAbsolutePath());
    }
    catch (IOException exc) {
        exc.printStackTrace();
    }
    catch (InterruptedException exc) {
        exc.printStackTrace();
    }
    catch (ExecutionException exc) {
        exc.printStackTrace();
    }
    finally {
        // Dispose of the context to shut down
        context.dispose();
    }

}

public static <T extends IntegerType<T>> void scale(
    final RandomAccessible<BitType> source, final IterableInterval<T> target)
{
    // create a cursor that automatically localizes itself on every move
    Cursor<T> targetCursor = target.localizingCursor();
    RandomAccess<BitType> sourceRandomAccess = source.randomAccess();
    // iterate over the input cursor
    while (targetCursor.hasNext()) {\
        // move input cursor forward
        targetCursor.fwd();
        // set the output cursor to the position of the input cursor
        sourceRandomAccess.setPosition(targetCursor);
        // set the value of this pixel of the output image
        BitType b = sourceRandomAccess.get();
        if (b.get()) {
            targetCursor.get().setOne();
        }
        else {
            targetCursor.get().setZero();
        }
    }
}