PromptDet: Expand Your Detector Vocabulary with Uncurated Images

Paper     Website


The goal of this work is to establish a scalable pipeline for expanding an object detector towards novel/unseen categories, using zero manual annotations. To achieve that, we make the following four contributions: (i) in pursuit of generalisation, we propose a two-stage open-vocabulary object detector that categorises each box proposal by a classifier generated from the text encoder of a pre-trained visual-language model; (ii) To pair the visual latent space (from RPN box proposal) with that of the pre-trained text encoder, we propose the idea of regional prompt learning to optimise a couple of learnable prompt vectors, converting the textual embedding space to fit those visually object-centric images; (iii) To scale up the learning procedure towards detecting a wider spectrum of objects, we exploit the available online resource, iteratively updating the prompts, and later self-training the proposed detector with pseudo labels generated on a large corpus of noisy, uncurated web images. The self-trained detector, termed as PromptDet, significantly improves the detection performance on categories for which manual annotations are unavailable or hard to obtain, e.g. rare categories. Finally, (iv) to validate the necessity of our proposed components, we conduct extensive experiments on the challenging LVIS and MS-COCO dataset, showing superior performance over existing approaches with fewer additional training images and zero manual annotations whatsoever.

Training framework

method overview


  • MMDetection version 2.16.0.

  • Please see for installation and the basic usage of MMDetection.


./tools/ configs/promptdet/ work_dirs/promptdet_mask_rcnn_r50_fpn_sample1e-3_mstrain_1x_lvis_v1.pth 4 --eval bbox segm


To be updated.


For your convenience, we provide the following trained models (PromptDet) with mask AP.

Model Epochs Scale Jitter Input Size APnovel APc APf AP Config Download
PromptDet_R_50_FPN_1x 12 640~800 800×800 19.0 18.5 25.8 21.4 config google / baidu
PromptDet_R_50_FPN_6x 72 100~1280 800×800 21.4 23.3 29.3 25.3 config google / baidu

[0] All results are obtained with a single model and without any test time data augmentation such as multi-scale, flipping and etc.. [1] Refer to more details in config files in config/promptdet/. [2] Extraction code of baidu netdisk: promptdet.


Thanks MMDetection team for the wonderful open source project!


If you find PromptDet useful in your research, please consider citing:

    title={PromptDet: Expand Your Detector Vocabulary with Uncurated Images},
    author={Feng, Chengjian and Zhong, Yujie and Jie, Zequn and Chu, Xiangxiang and Ren, Haibing and Wei, Xiaolin and Xie, Weidi and Ma, Lin},
    journal={arXiv preprint arXiv:2203.16513},


View Github