Get buffered image from byte array of raw data

Question

I am using JNA. and i am getting byte array of raw data from my c++ method. Now i am stuck how to get buffered image in java using this raw data byte array. I had tried few things to get it as tiff image but i dint get success. this are the code i tried so far. here my byte array contains data for 16 bit gray scale image. i get this data from x-sensor device. and now i need to get image from this byte array.

FIRST TRY

byte[] byteArray = myVar1.getByteArray(0, 3318000);//array of raw data

          ImageInputStream stream1=ImageIO.createImageInputStream(newByteArrayInputStream(byteArray));
            ByteArraySeekableStream stream=new ByteArraySeekableStream(byteArray,0,3318000);
                 BufferedImage bi = ImageIO.read(stream);

SECOND TRY

        SeekableStream stream = new ByteArraySeekableStream(byteArray);
         String[] names = ImageCodec.getDecoderNames(stream);


          ImageDecoder dec = ImageCodec.createImageDecoder(names[0], stream, null);
//at this line get the error ArrayIndexOutOfBoundsException: 0 
            RenderedImage im = dec.decodeAsRenderedImage();

I think i am missing here. As my array is containing raw data ,it does not containthen header for tiff image. m i right? if yes then how to provide this header in byte array. and eventually how to get image from this byte array?

to test that i am getting proper byte array from my native method i stored this byte array as .raw file and after opening this raw file in ImageJ software it sows me correct image so my raw data is correct. The only thing i need is that how to convert my raw byte array in image byte array?

Answer 1

Whether or not the byte array contains literally just pixel data or a structured image file such as TIFF etc really depends on where you got it from. It's impossible to answer that from the information provided.

However, if it does contain a structured image file, then you can generally:

• wrap a ByteArrayInputStream around it
• pass that stream to ImageIO.read()

If you just have literally raw pixel data, then you have a couple of main options:

• 'manually' get that pixel data so that it is in an int array with one int per pixel in ARGB format (the ByteBuffer and IntBuffer classes can help you with twiddling about with bytes)
• create a blank BufferedImage, then call its setRGB() method to set the actual pixel contents from your previously prepared int array

I think the above is easiest if you know what you're doing with the bits and bytes. However, in principle, you should be able to do the following:

• find a suitable WritableRaster.create... method method that will create a WritableRaster object wrapped around your data
• pass that WritableRaster into the relevant BufferedImage constructor to create your image.

Answer 2

Here is what I am using to convert raw pixel data to a BufferedImage. My pixels are signed 16-bit:

public static BufferedImage short2Buffered(short[] pixels, int width, int height) throws IllegalArgumentException {
    BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_USHORT_GRAY);
    short[] imgData = ((DataBufferShort)image.getRaster().getDataBuffer()).getData();
    System.arraycopy(pixels, 0, imgData, 0, pixels.length);     
    return image;
}

I'm then using JAI to encode the resulting image. Tell me if you need the code as well.

EDIT: I have greatly improved the speed thanks to @Brent Nash answer on a similar question.

EDIT: For the sake of completeness, here is the code for unsigned 8 bits:

public static BufferedImage byte2Buffered(byte[] pixels, int width, int height) throws IllegalArgumentException {
    BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_GRAY);
    byte[] imgData = ((DataBufferByte)image.getRaster().getDataBuffer()).getData();
    System.arraycopy(pixels, 0, imgData, 0, pixels.length);     
    return image;
}