OpenPose Demo - Overview

Forget about the OpenPose library code, just compile the library and use the demo ./build/examples/openpose/openpose.bin.

In order to learn how to use it, run ./build/examples/openpose/openpose.bin --help in your bash and read all the available flags (check only the flags for examples/openpose/openpose.cpp itself, i.e. the section Flags from examples/openpose/openpose.cpp:). We detail some of them in the following sections.

Running on Images, Video or Webcam

See doc/quick_start.md#quick-start.

Pose + Face + Hands

See doc/quick_start.md#quick-start.

Maximum Accuracy Configuration

See doc/quick_start.md#maximum-accuracy-configuration.

Reducing Latency/Lag

In general, there are 3 ways to reduce the latency (with some drawbacks each one):

• Reducing --output_resolution: It will slightly reduce the latency and increase the FPS. But the quality of the displayed image will deteriorate.
• Reducing --net_resolution and/or --face_net_resolution and/or --hand_net_resolution: It will increase the FPS and reduce the latency. But the accuracy will drop, specially for small people in the image.
• Enabling --disable_multi_thread: The latency should be reduced. But the speed will drop to 1-GPU speed (as it will only use 1 GPU). Note that it’s practical only for body, if hands and face are also extracted, it’s usually not worth it.

Kinect 2.0 as Webcam on Windows 10

Since the Windows 10 Anniversary, Kinect 2.0 can be read as a normal webcam. All you need to do is go to device manager, expand the kinect sensor devices tab, right click and update driver of WDF kinectSensor Interface. If you already have another webcam, disconnect it or use --camera 2.

JSON Output with No Visualization

The following example runs the demo video video.avi and outputs JSON files in output/. Note: see doc/output.md to understand the format of the JSON files.

# Only body
./build/examples/openpose/openpose.bin --video examples/media/video.avi --write_json output/ --display 0 --render_pose 0
# Body + face + hands
./build/examples/openpose/openpose.bin --video examples/media/video.avi --write_json output/ --display 0 --render_pose 0 --face --hand

JSON Output + Rendered Images Saving

The following example runs the demo video video.avi, renders image frames on output/result.avi, and outputs JSON files in output/. Note: see doc/output.md to understand the format of the JSON files.

./build/examples/openpose/openpose.bin --video examples/media/video.avi --write_video output/result.avi --write_json output/

Hands

# Fast method for speed
./build/examples/openpose/openpose.bin --hand
# Best results found with 6 scales
./build/examples/openpose/openpose.bin --hand --hand_scale_number 6 --hand_scale_range 0.4
# Adding tracking to Webcam (if FPS per GPU > 10 FPS) and Video
./build/examples/openpose/openpose.bin --video examples/media/video.avi --hand --hand_tracking
# Multi-scale + tracking is also possible
./build/examples/openpose/openpose.bin --video examples/media/video.avi --hand --hand_scale_number 6 --hand_scale_range 0.4 --hand_tracking

Rendering Face and Hands without Pose

# CPU rendering (faster)
./build/examples/openpose/openpose.bin --render_pose 0 --face --face_render 1 --hand --hand_render 1
# GPU rendering
./build/examples/openpose/openpose.bin --render_pose 0 --face --face_render 2 --hand --hand_render 2

Debugging Information

# Basic information
./build/examples/openpose/openpose.bin --logging_level 3
# Showing all messages
./build/examples/openpose/openpose.bin --logging_level 0

Selecting Some GPUs

The following example runs the demo video video.avi, parallelizes it over 2 GPUs, GPUs 1 and 2 (note that it will skip GPU 0):

./build/examples/openpose/openpose.bin --video examples/media/video.avi --num_gpu 2 --num_gpu_start 1

Heat Maps Storing

The following command will save all the body part heat maps, background heat map and Part Affinity Fields (PAFs) in the folder output_heatmaps_folder. It will save them on PNG format. Instead of individually saving each of the 67 heatmaps (18 body parts + background + 2 x 19 PAFs) individually, the library concatenate them vertically into a huge (width x #heatmaps) x (height) matrix. The PAFs channels are multiplied by 2 because there is one heatmpa for the x-coordinates and one for the y-coordinates. The order is body parts + bkg + PAFs. It will follow the sequence on POSE_BODY_PART_MAPPING in include/openpose/pose/poseParameters.hpp.

./build/examples/openpose/openpose.bin --video examples/media/video.avi --heatmaps_add_parts --heatmaps_add_bkg --heatmaps_add_PAFs --write_heatmaps output_heatmaps_folder/

Main Flags

We enumerate some of the most important flags, check the Flags Detailed Description section or run ./build/examples/openpose/openpose.bin --help for a full description of all of them.

• --face: Enables face keypoint detection.
• --hand: Enables hand keypoint detection.
• --video input.mp4: Read video.
• --camera 3: Read webcam number 3.
• --image_dir path_to_images/: Run on a folder with images.
• --ip_camera http://iris.not.iac.es/axis-cgi/mjpg/video.cgi?resolution=320x240?x.mjpeg: Run on a streamed IP camera. See examples public IP cameras here.
• --write_video path.avi: Save processed images as video.
• --write_images folder_path: Save processed images on a folder.
• --write_keypoint path/: Output JSON, XML or YML files with the people pose data on a folder.
• --process_real_time: For video, it might skip frames to display at real time.
• --disable_blending: If enabled, it will render the results (keypoint skeletons or heatmaps) on a black background, not showing the original image. Related: part_to_show, alpha_pose, and alpha_pose.
• --part_to_show: Prediction channel to visualize.
• --display 0: Display window not opened. Useful for servers and/or to slightly speed up OpenPose.
• --num_gpu 2 --num_gpu_start 1: Parallelize over this number of GPUs starting by the desired device id. By default it uses all the available GPUs.
• --model_pose MPI: Model to use, affects number keypoints, speed and accuracy.
• --logging_level 3: Logging messages threshold, range [0,255]: 0 will output any message & 255 will output none. Current messages in the range [1-4], 1 for low priority messages and 4 for important ones.

Flags Description

Each flag is divided into flag name, default value, and description.

1. Debugging/Other

   • DEFINE_int32(logging_level, 3, “The logging level. Integer in the range [0, 255]. 0 will output any log() message, while 255 will not output any. Current OpenPose library messages are in the range 0-4: 1 for low priority messages and 4 for important ones.”);
   • DEFINE_bool(disable_multi_thread, false, “It would slightly reduce the frame rate in order to highly reduce the lag. Mainly useful for 1) Cases where it is needed a low latency (e.g. webcam in real-time scenarios with low-range GPU devices); and 2) Debugging OpenPose when it is crashing to locate the error.”);
   • DEFINE_int32(profile_speed, 1000, “If PROFILER_ENABLED was set in CMake or Makefile.config files, OpenPose will show some runtime statistics at this frame number.”);

2. Producer

   • DEFINE_int32(camera, -1, “The camera index for cv::VideoCapture. Integer in the range [0, 9]. Select a negative number (by default), to auto-detect and open the first available camera.”);
   • DEFINE_string(camera_resolution, “-1x-1”, “Set the camera resolution (either --camera or --flir_camera). -1x-1 will use the default 1280x720 for --camera, or the maximum flir camera resolution available for --flir_camera“);
   • DEFINE_double(camera_fps, 30.0, “Frame rate for the webcam (also used when saving video). Set this value to the minimum value between the OpenPose displayed speed and the webcam real frame rate.”);
   • DEFINE_string(video, “”, “Use a video file instead of the camera. Use examples/media/video.avi for our default example video.”);
   • DEFINE_string(image_dir, “”, “Process a directory of images. Use examples/media/ for our default example folder with 20 images. Read all standard formats (jpg, png, bmp, etc.).”);
   • DEFINE_bool(flir_camera, false, “Whether to use FLIR (Point-Grey) stereo camera.”);
   • DEFINE_int32(flir_camera_index, -1, “Select -1 (default) to run on all detected flir cameras at once. Otherwise, select the flir camera index to run, where 0 corresponds to the detected flir camera with the lowest serial number, and n to the n-th lowest serial number camera.”);
   • DEFINE_string(ip_camera, “”, “String with the IP camera URL. It supports protocols like RTSP and HTTP.”);
   • DEFINE_uint64(frame_first, 0, “Start on desired frame number. Indexes are 0-based, i.e. the first frame has index 0.”);
   • DEFINE_uint64(frame_last, -1, “Finish on desired frame number. Select -1 to disable. Indexes are 0-based, e.g. if set to 10, it will process 11 frames (0-10).”);
   • DEFINE_bool(frame_flip, false, “Flip/mirror each frame (e.g. for real time webcam demonstrations).”);
   • DEFINE_int32(frame_rotate, 0, “Rotate each frame, 4 possible values: 0, 90, 180, 270.”);
   • DEFINE_bool(frames_repeat, false, “Repeat frames when finished.”);
   • DEFINE_bool(process_real_time, false, “Enable to keep the original source frame rate (e.g. for video). If the processing time is too long, it will skip frames. If it is too fast, it will slow it down.”);
   • DEFINE_string(camera_parameter_folder, “models/cameraParameters/flir/”, “String with the folder where the camera parameters are located.”);
   • DEFINE_bool(frame_keep_distortion, false, “If false (default), it will undistortionate the image based on the camera_parameter_folder camera parameters; if true, it will not undistortionate, i.e., it will leave it as it is.”);

3. OpenPose

   • DEFINE_string(model_folder, “models/”, “Folder path (absolute or relative) where the models (pose, face, …) are located.”);
   • DEFINE_string(output_resolution, “-1x-1”, “The image resolution (display and output). Use \”-1x-1\” to force the program to use the input image resolution.”);
   • DEFINE_int32(num_gpu, -1, “The number of GPU devices to use. If negative, it will use all the available GPUs in your machine.”);
   • DEFINE_int32(num_gpu_start, 0, “GPU device start number.”);
   • DEFINE_int32(keypoint_scale, 0, “Scaling of the (x,y) coordinates of the final pose data array, i.e. the scale of the (x,y) coordinates that will be saved with the write_json & write_keypoint flags. Select 0 to scale it to the original source resolution; 1to scale it to the net output size (set with net_resolution); 2 to scale it to the final output size (set with resolution); 3 to scale it in the range [0,1], where (0,0) would be the top-left corner of the image, and (1,1) the bottom-right one; and 4 for range [-1,1], where (-1,-1) would be the top-left corner of the image, and (1,1) the bottom-right one. Non related with scale_number and scale_gap.”);
   • DEFINE_int32(number_people_max, -1, “This parameter will limit the maximum number of people detected, by keeping the people with top scores. The score is based in person area over the image, body part score, as well as joint score (between each pair of connected body parts). Useful if you know the exact number of people in the scene, so it can remove false positives (if all the people have been detected. However, it might also include false negatives by removing very small or highly occluded people. -1 will keep them all.”);

4. OpenPose Body Pose

   • DEFINE_bool(body_disable, false, “Disable body keypoint detection. Option only possible for faster (but less accurate) face keypoint detection.”);
   • DEFINE_string(model_pose, “BODY_25”, “Model to be used. E.g. COCO (18 keypoints), MPI (15 keypoints, ~10% faster), MPI_4_layers (15 keypoints, even faster but less accurate).”);
   • DEFINE_string(net_resolution, “-1x368”, “Multiples of 16. If it is increased, the accuracy potentially increases. If it is decreased, the speed increases. For maximum speed-accuracy balance, it should keep the closest aspect ratio possible to the images or videos to be processed. Using -1 in any of the dimensions, OP will choose the optimal resolution depending on the other value introduced by the user. E.g. the default -1x368 is equivalent to 656x368 in 16:9 videos, e.g. full HD (1980x1080) and HD (1280x720) resolutions.”);
   • DEFINE_int32(scale_number, 1, “Number of scales to average.”);
   • DEFINE_double(scale_gap, 0.3, “Scale gap between scales. No effect unless scale_number > 1. Initial scale is always 1. If you want to change the initial scale, you actually want to multiply the net_resolution by your desired initial scale.”);

5. OpenPose Body Pose Heatmaps and Part Candidates

   • DEFINE_bool(heatmaps_add_parts, false, “If true, it will fill op::Datum::poseHeatMaps array with the body part heatmaps, and analogously face & hand heatmaps to op::Datum::faceHeatMaps & op::Datum::handHeatMaps. If more than one add_heatmaps_X flag is enabled, it will place then in sequential memory order: body parts + bkg + PAFs. It will follow the order on POSE_BODY_PART_MAPPING in src/openpose/pose/poseParameters.cpp. Program speed will considerably decrease. Not required for OpenPose, enable it only if you intend to explicitly use this information later.”);
   • DEFINE_bool(heatmaps_add_bkg, false, “Same functionality as add_heatmaps_parts, but adding the heatmap corresponding to background.”);
   • DEFINE_bool(heatmaps_add_PAFs, false, “Same functionality as add_heatmaps_parts, but adding the PAFs.”);
   • DEFINE_int32(heatmaps_scale, 2, “Set 0 to scale op::Datum::poseHeatMaps in the range [-1,1], 1 for [0,1]; 2 for integer rounded [0,255]; and 3 for no scaling.”);
   • DEFINE_bool(part_candidates, false, “Also enable write_json in order to save this information. If true, it will fill the op::Datum::poseCandidates array with the body part candidates. Candidates refer to all the detected body parts, before being assembled into people. Note that the number of candidates is equal or higher than the number of final body parts (i.e. after being assembled into people). The empty body parts are filled with 0s. Program speed will slightly decrease. Not required for OpenPose, enable it only if you intend to explicitly use this information.”);

6. OpenPose Face

   • DEFINE_bool(face, false, “Enables face keypoint detection. It will share some parameters from the body pose, e.g. model_folder. Note that this will considerable slow down the performance and increse the required GPU memory. In addition, the greater number of people on the image, the slower OpenPose will be.”);
   • DEFINE_string(face_net_resolution, “368x368”, “Multiples of 16 and squared. Analogous to net_resolution but applied to the face keypoint detector. 320x320 usually works fine while giving a substantial speed up when multiple faces on the image.”);

7. OpenPose Hand

   • DEFINE_bool(hand, false, “Enables hand keypoint detection. It will share some parameters from the body pose, e.g. model_folder. Analogously to --face, it will also slow down the performance, increase the required GPU memory and its speed depends on the number of people.”);
   • DEFINE_string(hand_net_resolution, “368x368”, “Multiples of 16 and squared. Analogous to net_resolution but applied to the hand keypoint detector.”);
   • DEFINE_int32(hand_scale_number, 1, “Analogous to scale_number but applied to the hand keypoint detector. Our best results were found with hand_scale_number = 6 and hand_scale_range = 0.4.”);
   • DEFINE_double(hand_scale_range, 0.4, “Analogous purpose than scale_gap but applied to the hand keypoint detector. Total range between smallest and biggest scale. The scales will be centered in ratio 1. E.g. if scaleRange = 0.4 and scalesNumber = 2, then there will be 2 scales, 0.8 and 1.2.”);
   • DEFINE_bool(hand_tracking, false, “Adding hand tracking might improve hand keypoints detection for webcam (if the frame rate is high enough, i.e. >7 FPS per GPU) and video. This is not person ID tracking, it simply looks for hands in positions at which hands were located in previous frames, but it does not guarantee the same person ID among frames.”);

8. OpenPose 3-D Reconstruction

   • DEFINE_bool(3d, false, “Running OpenPose 3-D reconstruction demo: 1) Reading from a stereo camera system. 2) Performing 3-D reconstruction from the multiple views. 3) Displaying 3-D reconstruction results. Note that it will only display 1 person. If multiple people is present, it will fail.”);
   • DEFINE_int32(3d_min_views, -1, “Minimum number of views required to reconstruct each keypoint. By default (-1), it will require all the cameras to see the keypoint in order to reconstruct it.”);
   • DEFINE_int32(3d_views, 1, “Complementary option to --image_dir or --video. OpenPose will read as many images per iteration, allowing tasks such as stereo camera processing (--3d). Note that --camera_parameters_folder must be set. OpenPose must find as many xml files in the parameter folder as this number indicates.”);

9. OpenPose Rendering

   • DEFINE_int32(part_to_show, 0, “Prediction channel to visualize (default: 0). 0 for all the body parts, 1-18 for each body part heat map, 19 for the background heat map, 20 for all the body part heat maps together, 21 for all the PAFs, 22-40 for each body part pair PAF.”);
   • DEFINE_bool(disable_blending, false, “If enabled, it will render the results (keypoint skeletons or heatmaps) on a black background, instead of being rendered into the original image. Related: part_to_show, alpha_pose, and alpha_pose.”);

10. OpenPose Rendering Pose

    • DEFINE_double(render_threshold, 0.05, “Only estimated keypoints whose score confidences are higher than this threshold will be rendered. Generally, a high threshold (> 0.5) will only render very clear body parts; while small thresholds (~0.1) will also output guessed and occluded keypoints, but also more false positives (i.e. wrong detections).”);
    • DEFINE_int32(render_pose, -1, “Set to 0 for no rendering, 1 for CPU rendering (slightly faster), and 2 for GPU rendering (slower but greater functionality, e.g. alpha_X flags). If -1, it will pick CPU if CPU_ONLY is enabled, or GPU if CUDA is enabled. If rendering is enabled, it will render both outputData and cvOutputData with the original image and desired body part to be shown (i.e. keypoints, heat maps or PAFs).”);
    • DEFINE_double(alpha_pose, 0.6, “Blending factor (range 0-1) for the body part rendering. 1 will show it completely, 0 will hide it. Only valid for GPU rendering.”);
    • DEFINE_double(alpha_heatmap, 0.7, “Blending factor (range 0-1) between heatmap and original frame. 1 will only show the heatmap, 0 will only show the frame. Only valid for GPU rendering.”);

11. OpenPose Rendering Face

    • DEFINE_double(face_render_threshold, 0.4, “Analogous to render_threshold, but applied to the face keypoints.”);
    • DEFINE_int32(face_render, -1, “Analogous to render_pose but applied to the face. Extra option: -1 to use the same configuration that render_pose is using.”);
    • DEFINE_double(face_alpha_pose, 0.6, “Analogous to alpha_pose but applied to face.”);
    • DEFINE_double(face_alpha_heatmap, 0.7, “Analogous to alpha_heatmap but applied to face.”);

12. OpenPose Rendering Hand

    • DEFINE_double(hand_render_threshold, 0.2, “Analogous to render_threshold, but applied to the hand keypoints.”);
    • DEFINE_int32(hand_render, -1, “Analogous to render_pose but applied to the hand. Extra option: -1 to use the same configuration that render_pose is using.”);
    • DEFINE_double(hand_alpha_pose, 0.6, “Analogous to alpha_pose but applied to hand.”);
    • DEFINE_double(hand_alpha_heatmap, 0.7, “Analogous to alpha_heatmap but applied to hand.”);

13. Display

    • DEFINE_bool(fullscreen, false, “Run in full-screen mode (press f during runtime to toggle).”);
    • DEFINE_bool(no_gui_verbose, false, “Do not write text on output images on GUI (e.g. number of current frame and people). It does not affect the pose rendering.”);
    • DEFINE_int32(display, -1, “Display mode: -1 for automatic selection; 0 for no display (useful if there is no X server and/or to slightly speed up the processing if visual output is not required); 2 for 2-D display; 3 for 3-D display (if --3d enabled); and 1 for both 2-D and 3-D display.”);

14. Result Saving

    • DEFINE_string(write_images, “”, “Directory to write rendered frames in write_images_format image format.”);
    • DEFINE_string(write_images_format, “png”, “File extension and format for write_images, e.g. png, jpg or bmp. Check the OpenCV function cv::imwrite for all compatible extensions.”);
    • DEFINE_string(write_video, “”, “Full file path to write rendered frames in motion JPEG video format. It might fail if the final path does not finish in .avi. It internally uses cv::VideoWriter. Flag camera_fps controls FPS.”);
    • DEFINE_string(write_json, “”, “Directory to write OpenPose output in JSON format. It includes body, hand, and face pose keypoints (2-D and 3-D), as well as pose candidates (if --part_candidates enabled).”);
    • DEFINE_string(write_coco_json, “”, “Full file path to write people pose data with JSON COCO validation format.”);
    • DEFINE_string(write_coco_foot_json, “”, “Full file path to write people foot pose data with JSON COCO validation format.”);
    • DEFINE_string(write_heatmaps, “”, “Directory to write body pose heatmaps in PNG format. At least 1 add_heatmaps_X flag must be enabled.”);
    • DEFINE_string(write_heatmaps_format, “png”, “File extension and format for write_heatmaps, analogous to write_images_format. For lossless compression, recommended png for integer heatmaps_scale and float for floating values.”);
    • DEFINE_string(write_keypoint, “”, “(Deprecated, use write_json) Directory to write the people pose keypoint data. Set format with write_keypoint_format.”);
    • DEFINE_string(write_keypoint_format, “yml”, “(Deprecated, use write_json) File extension and format for write_keypoint: json, xml, yaml & yml. Json not available for OpenCV < 3.0, use write_json instead.”);