Dedication

Large Dedicated to my parents. ii Acknowledgements Firstly, I would like to thank my advisor Prof Rob Fergus for his patience and insightful guidance. Rob introduce me to computer vision and deep learning. He was always eager to discuss new ideas at any time help me understand the research field quickly. Rob give me freedom and support to work on what I am really exciting. Rob is extremely supportive through my PhD time. I also thank to Prof Yann LeCun and Prof David Sontag for their guidance in the world of machine learning. Many thanks to my colleague: David Eigen, Matt Zeiler and Sixin Zhang for sharing sharing numerous late nights of work and intense collaboration. I would also to like to thank Ross Goroshin for insightful discussion, especially on unsupervised learning. Leo Zhu, Yuanhao Chen, Pierre Sermanet, and Clement Farabet for introducing me the subfield of detection in computer vision. Their suggestions and encouragement helped me overcome countless difficulties. Their knowledge and passion directly led me to choos