openpose/doc/demo_overview.md

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/installation.md#quick-start.

Pose + Face + Hands

See doc/installation.md#quick-start.

Maximum Accuracy Configuration

See doc/installation.md#quick-start.

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_keypoint_json output/ --no_display --render_pose 0
# Body + face + hands
./build/examples/openpose/openpose.bin --video examples/media/video.avi --write_keypoint_json output/ --no_display --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_keypoint_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.
• --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 selected, it will render the results on a black backgroung, not showing the original image. Related: part_to_show, alpha_pose, and alpha_pose.
• --part_to_show: Prediction channel to visualize.
• --no_display: 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.
• --net_resolution 656x368 --resolution 1280x720: For HD input (default values).
• --net_resolution 496x368 --resolution 640x480: For VGA input.
• --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

• 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.");

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, "1280x720", "Size of the camera frames to ask for.");
• DEFINE_double(camera_fps, 30.0, "Frame rate for the webcam (only used when saving video from webcam). 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_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.");

3. OpenPose

• DEFINE_string(model_folder, "models/", "Folder path (absolute or relative) where the models (pose, face, ...) are located.");
• DEFINE_string(resolution, "1280x720", "The image resolution (display and output). Use "-1x-1" to force the program to use the default images 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_keypoint & write_keypoint_json 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], and 4 for range [-1,1]. Non related with scale_number and scale_gap.");

4. OpenPose Body Pose

• DEFINE_string(model_pose, "COCO", "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, "656x368", "Multiples of 16. If it is increased, the accuracy usually 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. E.g. the default 656x368 is optimal for 16:9 videos, e.g. full HD (1980x1080) and HD (1280x720) videos.");
• 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.");
• DEFINE_bool(heatmaps_add_parts, false, "If true, it will add the body part heatmaps to the final op::Datum::poseHeatMaps array (program speed will decrease). Not required for our library, enable it only if you intend to process this information later. 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 include/openpose/pose/poseParameters.hpp.");
• 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.");

5. 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.");

6. 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");

7. 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 blending is enabled, it will merge the results with the original frame. If disabled, it will only display the results on a black background.");

8. 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, 2, "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 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.");

9. 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.");

10. 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.");

11. Display

• DEFINE_bool(fullscreen, false, "Run in full-screen mode (press f during runtime to toggle).");
• 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_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_bool(no_display, false, "Do not open a display window. Useful if there is no X server and/or to slightly speed up the processing if visual output is not required.");

12. 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.");
• DEFINE_string(write_keypoint, "", "Directory to write the people body pose keypoint data. Set format with write_keypoint_format.");
• DEFINE_string(write_keypoint_format, "yml", "File extension and format for write_keypoint: json, xml, yaml & yml. Json not available for OpenCV < 3.0, use write_keypoint_json instead.");
• DEFINE_string(write_keypoint_json, "", "Directory to write people pose data in *.json format, compatible with any OpenCV version.");
• DEFINE_string(write_coco_json, "", "Full file path to write people pose data with *.json COCO validation format.");
• DEFINE_string(write_heatmaps, "", "Directory to write 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. Recommended png or any compressed and lossless format.");