riding_horse.png: detected 0 instances in 0.10s

Hi everyone,

I followed the instructions in [here](https://detectron2.readthedocs.io/en/latest/tutorials/install.html) for the installation. Things went well. But then I tried running the [first demo](https://detectron2.readthedocs.io/en/latest/tutorials/getting_started.html). The model did not detect any object.

I have made **no change** to the code.

Instructions To Reproduce the Issue:
```
pyenv local 3.7.6
poetry init
poetry shell
python -m pip install 'git+https://github.com/facebookresearch/detectron2.git'
cd detectron2/demo/
python demo.py --config-file ../configs/COCO-InstanceSegmentation/mask_rcnn_R_50_FPN_3x.yaml --input ~/Downloads/riding_horse.png
```
And this is the __Full logs__ of what I got
```
[08/25 10:53:42 detectron2]: Arguments: Namespace(confidence_threshold=0.5, config_file='../configs/COCO-InstanceSegmentation/mask_rcnn_R_50_FPN_3x.yaml', input=['/home/tai/Downloads/riding_horse.png'], opts=[], output=None, video_input=None, webcam=False)
[08/25 10:53:44 fvcore.common.checkpoint]: [Checkpointer] Loading from detectron2://ImageNetPretrained/MSRA/R-50.pkl ...
[08/25 10:53:44 d2.checkpoint.c2_model_loading]: Renaming Caffe2 weights ......
[08/25 10:53:44 d2.checkpoint.c2_model_loading]: Following weights matched with submodule backbone.bottom_up:
| Names in Model | Names in Checkpoint | Shapes |
|:------------------|:-------------------------|:------------------------------------------------|
| res2.0.conv1.* | res2_0_branch2a_{bn_*,w} | (64,) (64,) (64,) (64,) (64,64,1,1) |
| res2.0.conv2.* | res2_0_branch2b_{bn_*,w} | (64,) (64,) (64,) (64,) (64,64,3,3) |
| res2.0.conv3.* | res2_0_branch2c_{bn_*,w} | (256,) (256,) (256,) (256,) (256,64,1,1) |
| res2.0.shortcut.* | res2_0_branch1_{bn_*,w} | (256,) (256,) (256,) (256,) (256,64,1,1) |
| res2.1.conv1.* | res2_1_branch2a_{bn_*,w} | (64,) (64,) (64,) (64,) (64,256,1,1) |
| res2.1.conv2.* | res2_1_branch2b_{bn_*,w} | (64,) (64,) (64,) (64,) (64,64,3,3) |
| res2.1.conv3.* | res2_1_branch2c_{bn_*,w} | (256,) (256,) (256,) (256,) (256,64,1,1) |
| res2.2.conv1.* | res2_2_branch2a_{bn_*,w} | (64,) (64,) (64,) (64,) (64,256,1,1) |
| res2.2.conv2.* | res2_2_branch2b_{bn_*,w} | (64,) (64,) (64,) (64,) (64,64,3,3) |
| res2.2.conv3.* | res2_2_branch2c_{bn_*,w} | (256,) (256,) (256,) (256,) (256,64,1,1) |
| res3.0.conv1.* | res3_0_branch2a_{bn_*,w} | (128,) (128,) (128,) (128,) (128,256,1,1) |
| res3.0.conv2.* | res3_0_branch2b_{bn_*,w} | (128,) (128,) (128,) (128,) (128,128,3,3) |
| res3.0.conv3.* | res3_0_branch2c_{bn_*,w} | (512,) (512,) (512,) (512,) (512,128,1,1) |
| res3.0.shortcut.* | res3_0_branch1_{bn_*,w} | (512,) (512,) (512,) (512,) (512,256,1,1) |
| res3.1.conv1.* | res3_1_branch2a_{bn_*,w} | (128,) (128,) (128,) (128,) (128,512,1,1) |
| res3.1.conv2.* | res3_1_branch2b_{bn_*,w} | (128,) (128,) (128,) (128,) (128,128,3,3) |
| res3.1.conv3.* | res3_1_branch2c_{bn_*,w} | (512,) (512,) (512,) (512,) (512,128,1,1) |
| res3.2.conv1.* | res3_2_branch2a_{bn_*,w} | (128,) (128,) (128,) (128,) (128,512,1,1) |
| res3.2.conv2.* | res3_2_branch2b_{bn_*,w} | (128,) (128,) (128,) (128,) (128,128,3,3) |
| res3.2.conv3.* | res3_2_branch2c_{bn_*,w} | (512,) (512,) (512,) (512,) (512,128,1,1) |
| res3.3.conv1.* | res3_3_branch2a_{bn_*,w} | (128,) (128,) (128,) (128,) (128,512,1,1) |
| res3.3.conv2.* | res3_3_branch2b_{bn_*,w} | (128,) (128,) (128,) (128,) (128,128,3,3) |
| res3.3.conv3.* | res3_3_branch2c_{bn_*,w} | (512,) (512,) (512,) (512,) (512,128,1,1) |
| res4.0.conv1.* | res4_0_branch2a_{bn_*,w} | (256,) (256,) (256,) (256,) (256,512,1,1) |
| res4.0.conv2.* | res4_0_branch2b_{bn_*,w} | (256,) (256,) (256,) (256,) (256,256,3,3) |
| res4.0.conv3.* | res4_0_branch2c_{bn_*,w} | (1024,) (1024,) (1024,) (1024,) (1024,256,1,1) |
| res4.0.shortcut.* | res4_0_branch1_{bn_*,w} | (1024,) (1024,) (1024,) (1024,) (1024,512,1,1) |
| res4.1.conv1.* | res4_1_branch2a_{bn_*,w} | (256,) (256,) (256,) (256,) (256,1024,1,1) |
| res4.1.conv2.* | res4_1_branch2b_{bn_*,w} | (256,) (256,) (256,) (256,) (256,256,3,3) |
| res4.1.conv3.* | res4_1_branch2c_{bn_*,w} | (1024,) (1024,) (1024,) (1024,) (1024,256,1,1) |
| res4.2.conv1.* | res4_2_branch2a_{bn_*,w} | (256,) (256,) (256,) (256,) (256,1024,1,1) |
| res4.2.conv2.* | res4_2_branch2b_{bn_*,w} | (256,) (256,) (256,) (256,) (256,256,3,3) |
| res4.2.conv3.* | res4_2_branch2c_{bn_*,w} | (1024,) (1024,) (1024,) (1024,) (1024,256,1,1) |
| res4.3.conv1.* | res4_3_branch2a_{bn_*,w} | (256,) (256,) (256,) (256,) (256,1024,1,1) |
| res4.3.conv2.* | res4_3_branch2b_{bn_*,w} | (256,) (256,) (256,) (256,) (256,256,3,3) |
| res4.3.conv3.* | res4_3_branch2c_{bn_*,w} | (1024,) (1024,) (1024,) (1024,) (1024,256,1,1) |
| res4.4.conv1.* | res4_4_branch2a_{bn_*,w} | (256,) (256,) (256,) (256,) (256,1024,1,1) |
| res4.4.conv2.* | res4_4_branch2b_{bn_*,w} | (256,) (256,) (256,) (256,) (256,256,3,3) |
| res4.4.conv3.* | res4_4_branch2c_{bn_*,w} | (1024,) (1024,) (1024,) (1024,) (1024,256,1,1) |
| res4.5.conv1.* | res4_5_branch2a_{bn_*,w} | (256,) (256,) (256,) (256,) (256,1024,1,1) |
| res4.5.conv2.* | res4_5_branch2b_{bn_*,w} | (256,) (256,) (256,) (256,) (256,256,3,3) |
| res4.5.conv3.* | res4_5_branch2c_{bn_*,w} | (1024,) (1024,) (1024,) (1024,) (1024,256,1,1) |
| res5.0.conv1.* | res5_0_branch2a_{bn_*,w} | (512,) (512,) (512,) (512,) (512,1024,1,1) |
| res5.0.conv2.* | res5_0_branch2b_{bn_*,w} | (512,) (512,) (512,) (512,) (512,512,3,3) |
| res5.0.conv3.* | res5_0_branch2c_{bn_*,w} | (2048,) (2048,) (2048,) (2048,) (2048,512,1,1) |
| res5.0.shortcut.* | res5_0_branch1_{bn_*,w} | (2048,) (2048,) (2048,) (2048,) (2048,1024,1,1) |
| res5.1.conv1.* | res5_1_branch2a_{bn_*,w} | (512,) (512,) (512,) (512,) (512,2048,1,1) |
| res5.1.conv2.* | res5_1_branch2b_{bn_*,w} | (512,) (512,) (512,) (512,) (512,512,3,3) |
| res5.1.conv3.* | res5_1_branch2c_{bn_*,w} | (2048,) (2048,) (2048,) (2048,) (2048,512,1,1) |
| res5.2.conv1.* | res5_2_branch2a_{bn_*,w} | (512,) (512,) (512,) (512,) (512,2048,1,1) |
| res5.2.conv2.* | res5_2_branch2b_{bn_*,w} | (512,) (512,) (512,) (512,) (512,512,3,3) |
| res5.2.conv3.* | res5_2_branch2c_{bn_*,w} | (2048,) (2048,) (2048,) (2048,) (2048,512,1,1) |
| stem.conv1.norm.* | res_conv1_bn_* | (64,) (64,) (64,) (64,) |
| stem.conv1.weight | conv1_w | (64, 3, 7, 7) |
WARNING [08/25 10:53:44 fvcore.common.checkpoint]: Some model parameters or buffers are not found in the checkpoint:
backbone.fpn_lateral2.{bias, weight}
backbone.fpn_lateral3.{bias, weight}
backbone.fpn_lateral4.{bias, weight}
backbone.fpn_lateral5.{bias, weight}
backbone.fpn_output2.{bias, weight}
backbone.fpn_output3.{bias, weight}
backbone.fpn_output4.{bias, weight}
backbone.fpn_output5.{bias, weight}
proposal_generator.rpn_head.anchor_deltas.{bias, weight}
proposal_generator.rpn_head.conv.{bias, weight}
proposal_generator.rpn_head.objectness_logits.{bias, weight}
roi_heads.box_head.fc1.{bias, weight}
roi_heads.box_head.fc2.{bias, weight}
roi_heads.box_predictor.bbox_pred.{bias, weight}
roi_heads.box_predictor.cls_score.{bias, weight}
roi_heads.mask_head.deconv.{bias, weight}
roi_heads.mask_head.mask_fcn1.{bias, weight}
roi_heads.mask_head.mask_fcn2.{bias, weight}
roi_heads.mask_head.mask_fcn3.{bias, weight}
roi_heads.mask_head.mask_fcn4.{bias, weight}
roi_heads.mask_head.predictor.{bias, weight}
WARNING [08/25 10:53:44 fvcore.common.checkpoint]: The checkpoint state_dict contains keys that are not used by the model:
fc1000.{bias, weight}
stem.conv1.bias
/media/tai/6TB/Projects/Segmentation/Detectron2/.venv/lib/python3.7/site-packages/torch/functional.py:445: UserWarning: torch.meshgrid: in an upcoming release, it will be required to pass the indexing argument. (Triggered internally at ../aten/src/ATen/native/TensorShape.cpp:2157.)
return _VF.meshgrid(tensors, **kwargs) # type: ignore[attr-defined]
[08/25 10:53:44 detectron2]: /home/tai/Downloads/riding_horse.png: detected 0 instances in 0.10s

```

## Expected behavior:

The model is expected to detect objects as being shown in [the Colaboratory example](https://colab.research.google.com/drive/16jcaJoc6bCFAQ96jDe2HwtXj7BMD_-m5) with multiple detected objects.

## Environment:

```
2022-08-25 11:03:19 URL:https://raw.githubusercontent.com/facebookresearch/detectron2/main/detectron2/utils/collect_env.py [8391/8391] -> "collect_env.py" [1]
---------------------- -----------------------------------------------------------------------------------------------------------
sys.platform linux
Python 3.7.6 (default, Nov 3 2021, 18:42:57) [GCC 9.3.0]
numpy 1.21.6
detectron2 0.6 @/media/tai/6TB/Projects/Segmentation/Detectron2/detectron2/detectron2
Compiler GCC 10.3
CUDA compiler CUDA 10.2
detectron2 arch flags 6.1
DETECTRON2_ENV_MODULE
PyTorch 1.10.2+cu102 @/media/tai/6TB/Projects/Segmentation/Detectron2/.venv/lib/python3.7/site-packages/torch
PyTorch debug build False
GPU available Yes
GPU 0 NVIDIA GeForce GTX 1080 Ti (arch=6.1)
Driver version 515.65.01
CUDA_HOME /usr/local/cuda-10.2
Pillow 9.2.0
torchvision 0.11.3+cu102 @/media/tai/6TB/Projects/Segmentation/Detectron2/.venv/lib/python3.7/site-packages/torchvision
torchvision arch flags 3.5, 5.0, 6.0, 7.0, 7.5
fvcore 0.1.5.post20220512
iopath 0.1.9
cv2 4.6.0
---------------------- -----------------------------------------------------------------------------------------------------------
PyTorch built with:
- GCC 7.3
- C++ Version: 201402
- Intel(R) Math Kernel Library Version 2020.0.0 Product Build 20191122 for Intel(R) 64 architecture applications
- Intel(R) MKL-DNN v2.2.3 (Git Hash 7336ca9f055cf1bfa13efb658fe15dc9b41f0740)
- OpenMP 201511 (a.k.a. OpenMP 4.5)
- LAPACK is enabled (usually provided by MKL)
- NNPACK is enabled
- CPU capability usage: AVX2
- CUDA Runtime 10.2
- NVCC architecture flags: -gencode;arch=compute_37,code=sm_37;-gencode;arch=compute_50,code=sm_50;-gencode;arch=compute_60,code=sm_60;-gencode;arch=compute_70,code=sm_70
- CuDNN 7.6.5
- Magma 2.5.2
- Build settings: BLAS_INFO=mkl, BUILD_TYPE=Release, CUDA_VERSION=10.2, CUDNN_VERSION=7.6.5, CXX_COMPILER=/opt/rh/devtoolset-7/root/usr/bin/c++, CXX_FLAGS= -Wno-deprecated -fvisibility-inlines-hidden -DUSE_PTHREADPOOL -fopenmp -DNDEBUG -DUSE_KINETO -DUSE_FBGEMM -DUSE_QNNPACK -DUSE_PYTORCH_QNNPACK -DUSE_XNNPACK -DSYMBOLICATE_MOBILE_DEBUG_HANDLE -DEDGE_PROFILER_USE_KINETO -O2 -fPIC -Wno-narrowing -Wall -Wextra -Werror=return-type -Wno-missing-field-initializers -Wno-type-limits -Wno-array-bounds -Wno-unknown-pragmas -Wno-sign-compare -Wno-unused-parameter -Wno-unused-variable -Wno-unused-function -Wno-unused-result -Wno-unused-local-typedefs -Wno-strict-overflow -Wno-strict-aliasing -Wno-error=deprecated-declarations -Wno-stringop-overflow -Wno-psabi -Wno-error=pedantic -Wno-error=redundant-decls -Wno-error=old-style-cast -fdiagnostics-color=always -faligned-new -Wno-unused-but-set-variable -Wno-maybe-uninitialized -fno-math-errno -fno-trapping-math -Werror=format -Wno-stringop-overflow, LAPACK_INFO=mkl, PERF_WITH_AVX=1, PERF_WITH_AVX2=1, PERF_WITH_AVX512=1, TORCH_VERSION=1.10.2, USE_CUDA=ON, USE_CUDNN=ON, USE_EXCEPTION_PTR=1, USE_GFLAGS=OFF, USE_GLOG=OFF, USE_MKL=ON, USE_MKLDNN=ON, USE_MPI=OFF, USE_NCCL=ON, USE_NNPACK=ON, USE_OPENMP=ON,

```

Hopefully someone know how to fix this. Thanks a lot for your attetion! :smiley: