Extract Image from BLOB OBJ in Oracle database table

Hi All,

I have a oracle database with tables in it. Some of the tables have fields of (BLOB), I know that these BLOBS contain pure jpeg image.

I can export the data in BLOB as matrices by MATLAB, these matrices are all one column matrices as I expected. However, what I really need to do is to have the .jpg image output. Does anyone have any idea how I could do this in MATLAB?

[Mustafa Zendaki]

can you please share the code of how you exported he blob into matlab, i would really appreciate it

Answer 1

[Walter Roberson]

If you want to display the image, you will have to write it to a file and use imread() .

There might be an undocumented method, or perhaps a JAVA method, of converting the byte stream in to an image array, but there is no documented MATLAB routine for doing this.

[Sean Lawson]

Thank you.

I do know there are some approaches in .NET, or SQL for example. But I am not sure that if matlab could do this, I do try to find some hints online but there's little. Could you tell me a little bit more?

Answer 2

[Aleksy Barski]

function [ image ] = deserializeImage( blob )
    obj = blob{1,1};
    is = obj.getBinaryStream();
    bufferedImage = javax.imageio.ImageIO.read(is);

      H = bufferedImage.getHeight;
      W = bufferedImage.getWidth;

      B = uint8(zeros([H,W,3]));
      pixelsData = uint8(bufferedImage.getData.getPixels(0,0,W,H,[]));
      for i = 1 : H
          base = (i-1)*W*3+1;
          B(i,1:W,:) = deal(reshape(pixelsData(base:(base+3*W-1)),3,W)');
      end
    
      image = B;
      clear  bufferedImage;
      clear is;
  end