/**
   * Reads image meta data.
   *
   * @param oimage
   * @return
   */
  public static Map<String, String> readImageData(IIOImage oimage) {
    Map<String, String> dict = new HashMap<String, String>();

    IIOMetadata imageMetadata = oimage.getMetadata();
    if (imageMetadata != null) {
      IIOMetadataNode dimNode = (IIOMetadataNode) imageMetadata.getAsTree("javax_imageio_1.0");
      NodeList nodes = dimNode.getElementsByTagName("HorizontalPixelSize");
      int dpiX;
      if (nodes.getLength() > 0) {
        float dpcWidth = Float.parseFloat(nodes.item(0).getAttributes().item(0).getNodeValue());
        dpiX = (int) Math.round(25.4f / dpcWidth);
      } else {
        dpiX = Toolkit.getDefaultToolkit().getScreenResolution();
      }
      dict.put("dpiX", String.valueOf(dpiX));

      nodes = dimNode.getElementsByTagName("VerticalPixelSize");
      int dpiY;
      if (nodes.getLength() > 0) {
        float dpcHeight = Float.parseFloat(nodes.item(0).getAttributes().item(0).getNodeValue());
        dpiY = (int) Math.round(25.4f / dpcHeight);
      } else {
        dpiY = Toolkit.getDefaultToolkit().getScreenResolution();
      }
      dict.put("dpiY", String.valueOf(dpiY));
    }

    return dict;
  }