The document discusses object detection techniques including R-CNN, SPPnet, Fast R-CNN, and Faster R-CNN. R-CNN uses region proposals and CNN features to classify each region. SPPnet improves efficiency by computing CNN features once for the whole image. Fast R-CNN further improves efficiency by sharing computation and using a RoI pooling layer. Faster R-CNN introduces a region proposal network to generate proposals, achieving end-to-end training. The techniques showed improved accuracy and processing speed over prior methods.