samples/imageprocessing/motion/denseopticalflow/README.md

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# Copyright (c) 2019-2020, NVIDIA CORPORATION.  All rights reserved.

@page dwx_denseopticalflow_sample Dense Optical Flow Sample
@tableofcontents

@section dwx_denseopticalflow_description Description

The Dense Optical Flow module sample demonstrates the Dense Optical Flow pipeline on multiple hardware units:
- VIC (Video Image Compositor).
- NVIDIA NVENC (NVIDIA Video Encoder).
- PVA (Programmable Vision Accelerator).

The Dense Optical Flow sample accepts RAW videos, h264 videos, or live camera input data from an AR0231 (revision >= 4) sensor. It then applies an optical flow algorithm to estimate motion vectors between frames.

@section dwx_denseopticalflow_sample_running Running the Sample

The DenseOpticalFlow sample, sample_denseopticalflow, accepts the following optional parameters. If none are specified, it performs detections on a supplied pre-recorded video.

    ./sample_denseopticalflow --input-type=[video|camera]
                              --video=[path/to/video]
                              --camera-type=[camera]
                              --camera-group=[a|b|c|d]
                              --camera-index=[0|1|2|3]
                              --estimationMode=[UHP|HP|HQ]
                              --nvencNo=[0|1]
                              --pvaNo=[0|1]

Where:

    --input-type=[video|camera]
            Defines if the input is from live camera or from a recorded video.
            Live camera is supported only on NVIDIA DRIVE(tm) platforms.
            It is not supported on Linux (x86 architecture) host systems.
            Default value: video

    --video=[path/to/video]
            Specifies the absolute or relative path of a raw, lraw or h264 recording.
            Only applicable if --input-type=video
            Default value: path/to/data/samples/stereo/left_1.h264

    --camera-type=[camera]
            Specifies a supported AR0231 `RCCB` sensor.
            Only applicable if --input-type=camera.
            Default value: ar0231-rccb-bae-sf3324

    --camera-group=[a|b|c]
            Is the group where the camera is connected to.
            Only applicable if --input-type=camera.
            Default value: a

    --camera-index=[0|1|2|3]
            Indicates the camera index on the given port.
            Default value: 0

    --estimationMode=[UHP|HP|HQ]
            Indicates the quality and the performance of Dense Optical Flow algorithm:
            - HP: High Performance
            - UHP: Ultra High Performance
            - HQ: High Quality
            Default value: HP

    --nvencNo=[0|1]
            Indicates on which Nvidia Video Encoder the corresponding stage of the pipeline is to be executed.
            Default value: 0

    --pvaNo=[0|1]
            Indicates on which PVA engine the corresponding stage of the pipeline is to be executed.
            Default value: 0

@subsection dwx_denseopticalflow_sample_examples Examples

### To run the sample on a video

    ./sample_denseopticalflow --input-type=video --video=<video file>

### To run the sample on a camera on NVIDIA DRIVE platforms

    ./sample_dense_opticalflow --input-type=camera --camera-type=<camera type> --camera-group=<camera group> --camera-index=<camera idx on camera group>

### To run the sample on non-default engines

    ./sample_denseopticalflow --nvencNo=1 --pvaNo=1


@section dwx_denseopticalflow_sample_output Output

The sample creates a window and displays a video with two sections. The section above demonstrates the original video,
whereas the section below shows the result of Dense Optical Flow with color coding presented at https://hci.iwr.uni-heidelberg.de/Correspondence_Visualization/.

![Dense Optical Flow](sample_denseopticalflow.png)

@subsection dwx_denseopticalflow_sample_more Additional information

For more information, see @ref denseopticalflow_mainsection.