@Michael_Hsu: Hello, I am not sure if this is the right forum to ask this question since it is mainly for Pytorch related questions. But I would be glad to suggest some references that you may find interesting related to captioning and detection:

https://cs.stanford.edu/people/karpathy/sfmltalk.pdf 3
https://www.youtube.com/watch?v=yk6XDFm3J2c 3
https://medium.com/mlreview/multi-modal-methods-image-captioning-from-translation-to-attention-895b6444256e 5
https://www.coursera.org/lecture/convolutional-neural-networks/object-detection-VgyWR 2

I hope this helps!