how to get the image position from pdf file in objective c?

I am doing something like extracting the pdf text in a string format so as to annotate the text and in the same process i need to find the image positions covered in the same pdf file so as to maintain its position. Now the problem is that i am not getting the exact positions 开发者_Go百科of the images in the same pdf file. Is it possible to use some thing like OCR,if yes,how to use that?

Can anybody help me in finding the exact position of the image in the pdf file? I need to implement some pdf reader kind of application for ipad,that's just for the knowledge.

Thank you.

Isn't OCR a little bit heavy weight for iphone? Take look on tools like pdftotext from Xpdf. It is much simpler to read data, as to render and recognize it back again.