Existing image captioning models do not generalize well to out-of-domain
images containing novel scenes or objects. This limitation severely hinders the
use of these models in real world applications dealing with images in the wild.
We address this problem using a flexible approach that enables existing deep
captioning architectures to take advantage of image taggers at test time,
without re-training. Our method uses constrained beam search to force the
inclusion of selected tag words in the output, and fixed, pretrained word
embeddings to facilitate vocabulary expansion to previously unseen tag words.
Using this approach we achieve state of the art results for out-of-domain
captioning on MSCOCO (and improved results for in-domain captioning). Perhaps
surprisingly, our results significantly outperform approaches that incorporate
the same tag predictions into the learning algorithm. We also show that we can
significantly improve the quality of generated ImageNet captions by leveraging
ground-truth labels.

使用约束束搜索的方法和固定的预训练词嵌入，使得现有的深度图像描述模型能够利用图像标签器在测试阶段进行标注，从而实现新颖场景或对象的图像生成。该方法的结果表明了它在 MSCOCO 上获得了良好的表现，甚至优于采用相同标签预测的学习算法。同时，我们还证明了我们可以通过利用 ground-truth 标签来显着提高生成的 ImageNet 标题的质量。