How to build a Caffe dataset for object detection with ImageNet data

I am new into Caffe and I have some trouble in understanding how should I create a dataset for object detection. I have downloaded some images and bounding boxes from ImageNet. The bounding boxes are in Pascal VOC format (xml files). As I understood, this is not the only format for bounding boxes. However, I want to build a dataset that can be fed to a Caffe network. Again, I know that there are several suitable formats. For now, I am not interested in performance. What is the easiest method to build the dataset?