Title: Open-Vocabulary Object Detection upon Frozen Vision and Language Models. Abstract: We present F-VLM, a simple open-vocabulary object detection method built uponFrozenVision andLanguageModels.  F-VLM simplifies the current multi-stage training pipeline by eliminating the need for knowledge distillation or detection-tailored pretraining.  Surprisingly, we observe that a frozen VLM: 1) retains the locality-sensitive features necessary for detection, and 2) is a strong region classifier.  We finetune only the detector head and combine the detector and VLM outputs for each region at inference time.  F-VLM shows compelling scaling behavior and achieves +6.5 mask AP improvement over the previous state of theart  on  novel  categories  of  LVIS  open-vocabulary  detection  benchmark. In addition, we demonstrate very competitive results on COCO open-vocabulary detection benchmark and cross-dataset transfer detection, in addition to significant training speed-up and compute savings. Code will be released.
