getBufferedImage() in ImagePlus returns wrong type

Posted by Harry Oswald on Oct 09, 2009; 10:24am
URL: http://imagej.273.s1.nabble.com/getBufferedImage-in-ImagePlus-returns-wrong-type-tp3690882.html

hi
I tried to convert an image to 8bit grayscale using imageJ api.
The code snippet is as follows

..
import ij.IJ;
import ij.ImagePlus;
import ij.process.ImageConverter;
import java.awt.image.BufferedImage;
....

public static void toGrayscale(){
    ImagePlus imp=new ImagePlus("F:\\myimgs\\Picture 001.jpg");
    if (imp.getType() == ImagePlus.GRAY8){
        System.out.println("gray8");
    }else{
        System.out.println("orig image color mode="+imp.getType());
        ImageConverter ic = new ImageConverter(imp);
        ic.convertToGray8();
        IJ.saveAs(imp, "png", "F:\\myimgs\\newimage.png");
        BufferedImage bufferedImage=imp.getBufferedImage();
        if (imp.getType() == ImagePlus.GRAY8){
            System.out.println("after conversion, type is gray8");
            System.out.println("bufferedImage type
is="++bufferedImage.getType());
        }else{
                System.out.println("still imp is="+imp.getType());
                System.out.println("bufferedimg type
is="+bufferedImage.getType());

                }
                       
}

however ,when I run this using a truecolor image,I get the following output.

orig image color mode=4    // COLOR_RGB as per ImageJ docs
after conversion, type is gray8
bufferedimg type is=13      // TYPE_BYTE_INDEXED as per jdk doc

I am confused by the value 13.Shouldn't it be 10 viz TYPE_BYTE_GRAY ?can
someone tell me

why this is happening?
thanks a lot
harry.