Estou tentando extrair imagens de um pdf usando o pdfbox. O exemplo pdfaqu

Mas estou recebendo apenas imagens em branco.

O código que estou tentando: -

public static void main(String[] args) {
   PDFImageExtract obj = new PDFImageExtract();
    try {
        obj.read_pdf();
    } catch (IOException ex) {
        System.out.println("" + ex);
    }

}

 void read_pdf() throws IOException {
    PDDocument document = null; 
    try {
        document = PDDocument.load("C:\\Users\\Pradyut\\Documents\\MCS-034.pdf");
    } catch (IOException ex) {
        System.out.println("" + ex);
    }
    List pages = document.getDocumentCatalog().getAllPages();
    Iterator iter = pages.iterator(); 
    int i =1;
    String name = null;

    while (iter.hasNext()) {
        PDPage page = (PDPage) iter.next();
        PDResources resources = page.getResources();
        Map pageImages = resources.getImages();
        if (pageImages != null) { 
            Iterator imageIter = pageImages.keySet().iterator();
            while (imageIter.hasNext()) {
                String key = (String) imageIter.next();
                PDXObjectImage image = (PDXObjectImage) pageImages.get(key);
                image.write2file("C:\\Users\\Pradyut\\Documents\\image" + i);
                i ++;
            }
        }
    }

}

Obrigad