使用任何NLP工具从PDF读取表格和图像

In one of my NLP assignments I have to read PDF files and extract information out of them. Using Java I am able to read the textual content from PDF and able to apply our NLP algorithms on the text, but I also need to extract information present in Tables in PDF, I am trying to read them but not able to get them in proper format. Any idea how I can read tables from PDF document , or any hint if any library is available in OpenNLP, GATE, Stanford NLP for achieving these. In one of my NLP assignments I have to read PDF