Question

I know the image is valid because I can convert the IplImage to an Image and even draw it on a JPanel. But when I convert a byte array to an Image most of the time I get null reference to an Image. Look at this code below to get a picture what I am facing with and comments, questions, answers are all welcome and even tips are all welcome.

            Image i = Convert.getImage(image);
            byte[] buffer  = Convert.getBytes(image);
            Image  i2 = Convert.getImage(buffer); 
            //i2 is a null reference and i is a valid image. i can be drawn but i2 is useless.

Convert class:

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package Security;

import com.googlecode.javacv.cpp.opencv_core.IplImage;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.io.ByteArrayInputStream;
import javax.imageio.ImageIO;
import javax.imageio.ImageReader;

/**
 *
 * @author danny
 */
public final class Convert
{

        public static Image getImage(IplImage image)
        {
                return image.getBufferedImage();
        }

        public static byte[] getBytes(IplImage image)
        {
                byte[] buffer;
                BufferedImage bI = image.getBufferedImage();
                buffer = ((DataBufferByte) (bI).getRaster().getDataBuffer()).getData();
                return buffer;
        }

        public static String getString(byte[] buffer)
        {
                return new String(buffer);
        }
        public static Image getImage(byte[] buffer)
        {
                try
                {

                        Image i = ImageIO.read(new ByteArrayInputStream(buffer));
                        return i;
                }
                catch (Exception e)
                {
                        System.out.printf("Exception Message:\n%s", e.getMessage() );
                        return null;
                }

        }
}

Now some of you may ask why do I need as a byte array. Well because I need to send across a network.

Extra Things To Be Aware Of:

1. No exception is being thrown
2. IplImage is a valid object

Update:

I have tried using the ToolKit class to create an image from a byte array. But it fails probably because it is not a JPEG or GIF. Although it does return a valid Image object the Image object is pointing to an image that is blank. Here is the code I was trying to use but failed to do so.

public static Image getImage(byte[] buffer)
{
        try
        {
                Toolkit  toolkit = Toolkit.getDefaultToolkit();
                Image i =  toolkit.createImage(buffer);
                return i;
        }
        catch (Exception e)
        {
                System.out.printf("Exception Message:\n%s", e.getMessage() );
                return null;
        }

}

Answer 1

DataBufferByte.getData will: “Returns the default (first) byte data array.” The first bank that is. That seems an uncertain, incomplete way to get the bytes; especially on the way back. Besides there is the implementation dependent cast from DataBuffer to DataBufferByte.

ImageIO can write to an OutputStream, for instance to a ByteArrayOutputStream, of which you can take the bytes. And on the other side ImageIO can read it in again. That is not the pure only-pixel-data you had in mind, but fool-proof.