forked from ray/RobotKernal-UESTC
222 lines
7.0 KiB
Plaintext
222 lines
7.0 KiB
Plaintext
/** @mainpage API Reference
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Older versions: [0.1](0.1).
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Introduction
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============
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%libfreenect2 is an open source cross-platform driver for Kinect for Windows v2
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devices. For information on installation and troubleshooting, see the
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[GitHub repository](https://github.com/OpenKinect/libfreenect2).
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This documentation is designed for application developers who want to extract
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and use depth and color images from Kinect v2 for further processing.
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Additional questions and comments not covered by this documentation can be
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posted to [GitHub issues](https://github.com/OpenKinect/libfreenect2/issues).
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This documentation may require some understanding on camera calibration and 3-D
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geometry.
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Features
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========
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- Color image processing
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- IR and depth image processing
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- Registration of color and depth images
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- Multiple GPU and hardware acceleration implementations for image processing
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### Issues and Future Work
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- Audio. Raw audio is accessible via Linux USB audio. There is no support for
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the calibrated directional audio.
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- Unstable USB and crashes. Due to differences in driver support, USB problems
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can happen a lot. Error handling in %libfreenect2 is not fully verified for
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production use.
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- Firmware upload. The protocol has been reverse engineered, but use Windows
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for this right now.
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- Example of multiple Kinects.
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- Example utility of dumping image frames.
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- API for on-demand processing.
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- Verification of systematic errors through accurate calibration.
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- Bindings for C, Python, Java, etc.
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Getting Started
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===============
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To read the API documentation, start with the [Modules](modules.html) page
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which nicely organizes classes according to their functionalities.
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Example programs can be found in the source distribution under the `examples`
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directory. There also includes an example CMake build system for a standalone
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application that uses %libfreenect2 binary installation.
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Many internal details are hidden from this public API. For details on Kinect
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v2's USB protocols, depth decoding algorithms, calibration algorithms, and how
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to implement performance optimizers, you are encouraged to read the source
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code. The source code is the updated and authoritative reference for any
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functionalities.
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Environment Variables
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=====================
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There are a few environment variables providing controls for both end-users and
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programmers:
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* `LIBFREENECT2_LOGGER_LEVEL`: The default logging level if not explicitly set
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by the code.
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* `LIBFREENECT2_PIPELINE`: The default pipeline if not explicitly set by the
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code.
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* `LIBFREENECT2_RGB_TRANSFER_SIZE`, `LIBFREENECT2_RGB_TRANSFERS`,
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`LIBFREENECT2_IR_PACKETS`, `LIBFREENECT2_IR_TRANSFERS`: Tuning the USB buffer
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sizes. Use only if you know what you are doing.
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You can also see the following walkthrough for the most basic usage.
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Walkthrough
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===========
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Here is an example to walk you through the API. See `examples/Protonect.cpp`
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for the full source.
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Headers
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-------
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First, include necessary headers. `registration.h` and `logger.h` are optional
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if you don't use them.
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@snippet Protonect.cpp headers
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Logging
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-------
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This shows how to set up the logger and logging level.
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@snippet Protonect.cpp logging
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Though @copydetails libfreenect2::createConsoleLoggerWithDefaultLevel
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You can implement a custom [Logger](@ref libfreenect2::Logger) and redirect
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%libfreenect2's log messages to desired places.
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Here is an example to save log messages to a file.
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@snippet Protonect.cpp logger
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And use it
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@snippet Protonect.cpp file logging
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%libfreenect2 uses a single global logger regardless of number of contexts and
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devices. You may have to implement thread safety measure in
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[log()](@ref libfreenect2::Logger::log), which is called from multiple threads.
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Console loggers are thread safe because `std::cout` and `std::cerr` are thread
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safe.
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Initialize and Discover Devices
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-------------------------------
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You need these structures for all operations. Here it uses only one device.
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@snippet Protonect.cpp context
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You must enumerate all Kinect v2 devices before doing anything else related to
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devices.
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@snippet Protonect.cpp discovery
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Also, you can create a specific [PacketPipeline](@ref libfreenect2::PacketPipeline)
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instead using the default one for opening the device. Alternatives include
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[OpenGLPacketPipeline](@ref libfreenect2::OpenGLPacketPipeline),
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[OpenCLPacketPipeline](@ref libfreenect2::OpenCLPacketPipeline), etc.
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@snippet Protonect.cpp pipeline
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Open and Configure the Device
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-----------------------------
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Now you can open the device by its serial number, and using the specific
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pipeline.
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@snippet Protonect.cpp open
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You can also open the device without providing a pipeline, then a default is
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used. There are a few alternative ways to [openDevice()](@ref libfreenect2::Freenect2::openDevice).
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After opening, you need to attach [Framelisteners](@ref libfreenect2::FrameListener)
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to the device to receive images frames.
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This [SyncMultiFrameListener](@ref libfreenect2::SyncMultiFrameListener) will
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wait until all specified types of frames are received once. Like loggers, you
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may also implement your own frame listeners using the same interface.
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@snippet Protonect.cpp listeners
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You cannot configure the device after starting it.
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Start the Device
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----------------
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After finishing configuring the device, you can start the device. You must
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start the device before querying any information of the device.
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@snippet Protonect.cpp start
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You can [setIrCameraParams()](@ref libfreenect2::Freenect2Device::setIrCameraParams)
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after start if you have your own depth calibration parameters.
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Otherwise you can also use the factory preset parameters for
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[Registration](@ref libfreenect2::Registration). You can also provide your own
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depth calibration parameterss (though not color camera calibration parameters
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right now). Registration is optional.
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@snippet Protonect.cpp registration setup
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At this time, the processing has begun, and the data flows through the pipeline
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towards your frame listeners.
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Receive Image Frames
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--------------------
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This example uses a loop to receive image frames.
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@snippet Protonect.cpp loop start
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[waitForNewFrame()](@ref libfreenect2::SyncMultiFrameListener::waitForNewFrame)
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here will block until required frames are all received, and then you can
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extract `Frame` according to the type.
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See libfreenect2::Frame for details about pixel format, dimensions, and
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metadata.
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You can do your own things using the frame data. You can feed it to OpenCV,
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PCL, etc. Here, you can perform registration:
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@snippet Protonect.cpp registration
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After you are done with this frame, you must release it.
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@snippet Protonect.cpp loop end
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Stop the Device
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---------------
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If you are finished and no longer need to receive more frames, you can stop
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the device and exit.
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@snippet Protonect.cpp stop
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Pause the Device
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----------------
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You can also temporarily pause the device with
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[stop()](@ref libfreenect2::Freenect2Device::stop) and
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[start()](@ref libfreenect2::Freenect2Device::start).
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@snippet Protonect.cpp pause
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Doing this during `waitForNewFrame()` should be thread safe, and tests also
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show well. But a guarantee of thread safety has not been checked yet.
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THE END.
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*/
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