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API How-To

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TODO:

  • Fetch frame width, height, bytes-per-pixel and stride in bytes
  • Fetch frame time-stamp and per-frame metadata
  • Get color aligned to depth and vice-versa

Get first RealSense device

  • librealsense1:
rs::context ctx;
if (ctx.get_device_count() == 0) 
    throw std::runtime_error("No device detected. Is it plugged in?");
rs::device & dev = *ctx.get_device(0);
  • librealsense2:
rs2::context ctx;
auto list = ctx.query_devices(); // Get a snapshot of currently connected devices
if (list.size() == 0) 
    throw std::runtime_error("No device detected. Is it plugged in?");
rs2::device dev = list.front();

Start Streaming with Default Configuration

  • librealsense1:
rs::context ctx;
rs::device & dev = *ctx.get_device(0);
dev.enable_stream(rs::stream::color, rs::preset::best_quality);
dev.enable_stream(rs::stream::depth, rs::preset::best_quality);
dev.start();
  • librealsense2:
rs2::pipeline pipe;
pipe.start();

Start Streaming Left and Right Infrared Imagers

  • librealsense1:
rs::context ctx;
rs::device & dev = *ctx.get_device(0);
dev.enable_stream(rs::stream::infrared, rs::preset::best_quality);
dev.enable_stream(rs::stream::infrared2, rs::preset::best_quality);
dev.start();
  • librealsense2:
rs2::config cfg;
cfg.enable_stream(RS2_STREAM_INFRARED, 1);
cfg.enable_stream(RS2_STREAM_INFRARED, 2);
rs2::pipeline pipe;
pipe.start(cfg);

Wait for Coherent Set of Frames

  • librealsense1:
rs::context ctx;
rs::device & dev = *ctx.get_device(0);
dev.enable_stream(rs::stream::color, rs::preset::best_quality);
dev.enable_stream(rs::stream::depth, rs::preset::best_quality);
dev.start();
dev.wait_for_frames();
dev.get_frame_data(rs::stream::depth); // Pointer to depth pixels, 
// invalidated by next call to wait/poll for frames
  • librealsense2:
rs2::pipeline pipe;
pipe.start();
rs2::frameset frames = pipe.wait_for_frames();
rs2::frame frame = frames.first(RS2_STREAM_DEPTH);
if (frame)
    frame.get_data(); // Pointer to depth pixels, 
                      // invalidated when last copy of frame goes out of scope

Poll for Frames

  • librealsense1:
rs::context ctx;
rs::device & dev = *ctx.get_device(0);
dev.enable_stream(rs::stream::color, rs::preset::best_quality);
dev.enable_stream(rs::stream::depth, rs::preset::best_quality);
dev.start();
if (dev.poll_for_frames())
    dev.get_frame_data(rs::stream::depth);
  • librealsense2:
rs2::pipeline pipe;
pipe.start();
rs2::frameset frames;
if (pipe.poll_for_frames(&frames))
{
    rs2::frame depth_frame = frames.first(RS2_STREAM_DEPTH);
    depth_frame.get_data();
}

Do Processing on a Background-Thread

  • librealsense1:
rs::context ctx;
rs::device & dev = *ctx.get_device(0);
dev.enable_stream(rs::stream::depth, rs::preset::best_quality);
dev.start();

std::mutex m;
std::deque<std::vector<uint8_t>> queue;
std::thread t([&]() {
    while (true)
    {
        std::vector<uint8_t> frame_copy;
        {
            std::lock_guard<std::mutex> lock(m);
            frame_copy = queue.front();
            queue.front();
        }
        frame_copy.data();
        // Do processing on the frame
    }
});
t.detach();

while (true)
{
    dev.wait_for_frames();
    const auto stream = rs::stream::depth;
    const auto CAPACITY = 5; // allow max latency of 5 frames
    uint8_t bytes_per_pixel = 1;
    switch (dev.get_stream_format(stream))
    {
    case rs::format::raw8:
    case rs::format::y8:
        bytes_per_pixel = 1;
        break;
    case rs::format::z16:
    case rs::format::disparity16:
    case rs::format::yuyv:
    case rs::format::y16:
    case rs::format::raw10:
    case rs::format::raw16:
        bytes_per_pixel = 2;
        break;
    case rs::format::rgb8:
    case rs::format::bgr8:
        bytes_per_pixel = 3;
        break;
    case rs::format::rgba8:
    case rs::format::bgra8:
    case rs::format::xyz32f:
        bytes_per_pixel = 4;
        break;
    }
    auto ptr = (uint8_t*)dev.get_frame_data(rs::stream::depth);
    std::vector<uint8_t> frame_copy( // Deep-copy the frame data
        ptr, ptr + dev.get_stream_width(stream) *
                   dev.get_stream_height(stream) *
                   bytes_per_pixel);
    {
        std::lock_guard<std::mutex> lock(m);
        if (queue.size() < CAPACITY)
	        queue.push_back(frame_copy);
    }
}
  • librealsense2:
rs2::pipeline pipe;
pipe.start();

const auto CAPACITY = 5; // allow max latency of 5 frames
rs2::frame_queue queue(CAPACITY);
std::thread t([&]() {
    while (true)
    {
        rs2::depth_frame frame;
        if (queue.poll_for_frame(&frame))
        {
	        frame.get_data();
	        // Do processing on the frame
        }
    }
});
t.detach();

while (true)
{
    auto frames = pipe.wait_for_frames();
    queue.enqueue(frames.get_depth_frame());
}

Get and Apply Depth-to-Color Extrinsics

  • librealsense1:
rs::context ctx;
rs::device & dev = *ctx.get_device(0);
dev.enable_stream(rs::stream::color, rs::preset::best_quality);
dev.enable_stream(rs::stream::depth, rs::preset::best_quality);
dev.start();
rs::extrinsics e = dev.get_extrinsics(rs::stream::depth, rs::stream::color);
// Apply extrinsics to the origin
auto color_point = e.transform({ 0.f, 0.f, 0.f });
  • librealsense2:
rs2::pipeline pipe;
rs2::pipeline_profile selection = pipe.start();
auto depth_stream = selection.get_stream(RS2_STREAM_DEPTH);
auto color_stream = selection.get_stream(RS2_STREAM_COLOR);
rs2_extrinsics e = depth_stream.get_extrinsics_to(color_stream);
// Apply extrinsics to the origin
float origin[3] { 0.f, 0.f, 0.f };
float target[3];
rs2_transform_point_to_point(target, &e, origin);

Get Disparity Baseline

  • librealsense1:
rs::context ctx;
rs::device & dev = *ctx.get_device(0);
dev.enable_stream(rs::stream::infrared, rs::preset::best_quality);
dev.enable_stream(rs::stream::infrared2, rs::preset::best_quality);
dev.start();
rs_extrinsics e = dev.get_extrinsics(rs::stream::infrared, rs::stream::infrared2);
auto baseline = e.translation[0];
  • librealsense2:
rs2::config cfg;
cfg.enable_stream(RS2_STREAM_INFRARED, 1);
cfg.enable_stream(RS2_STREAM_INFRARED, 2);
rs2::pipeline pipe;
rs2::pipeline_profile selection = pipe.start(cfg);
auto ir1_stream = selection.get_stream(RS2_STREAM_INFRARED, 1);
auto ir2_stream = selection.get_stream(RS2_STREAM_INFRARED, 2);
rs2_extrinsics e = ir1_stream.get_extrinsics_to(ir2_stream);
auto baseline = e.translation[0];

Get Video Stream Intrinsics

  • librealsense1:
rs::context ctx;
rs::device & dev = *ctx.get_device(0);
dev.enable_stream(rs::stream::infrared, rs::preset::best_quality);
dev.enable_stream(rs::stream::infrared2, rs::preset::best_quality);
dev.start();

rs::intrinsics i = dev.get_stream_intrinsics(rs::stream::depth);
auto principal_point = std::make_pair(i.ppx, i.ppy);
auto focal_length = std::make_pair(i.fx, i.fy);
auto resolution = std::make_pair(i.width, i.height);
rs_distortion model = i.model;
  • librealsense2:
rs2::pipeline pipe;
rs2::pipeline_profile selection = pipe.start();
auto depth_stream = selection.get_stream(RS2_STREAM_DEPTH)
                             .as<rs2::video_stream_profile>();
auto resolution = std::make_pair(depth_stream.width(), depth_stream.height());
auto i = depth_stream.get_intrinsics();
auto principal_point = std::make_pair(i.ppx, i.ppy);
auto focal_length = std::make_pair(i.fx, i.fy);
rs2_distortion model = i.model;

Get Field of View

  • librealsense1:
rs::context ctx;
rs::device & dev = *ctx.get_device(0);
dev.enable_stream(rs::stream::infrared, rs::preset::best_quality);
dev.enable_stream(rs::stream::infrared2, rs::preset::best_quality);
dev.start();

rs::intrinsics i = dev.get_stream_intrinsics(rs::stream::depth);
float fov[2] = { i.hfov, i.vfov };
  • librealsense2:
rs2::pipeline pipe;
rs2::pipeline_profile selection = pipe.start();
auto depth_stream = selection.get_stream(RS2_STREAM_DEPTH)
                             .as<rs2::video_stream_profile>();
auto i = depth_stream.get_intrinsics();
float fov[2]; // X, Y fov
rs2_fov(&i, fov);

Get Depth Units

  • librealsense1:
rs::context ctx;
rs::device & dev = *ctx.get_device(0);
dev.enable_stream(rs::stream::infrared, rs::preset::best_quality);
dev.enable_stream(rs::stream::infrared2, rs::preset::best_quality);
dev.start();

auto scale = dev.get_depth_scale();
  • librealsense2:
rs2::pipeline pipe;
rs2::pipeline_profile selection = pipe.start();

// Find first depth sensor (devices can have zero or more then one)
auto sensor = selection.get_device().first<rs2::depth_sensor>();
auto scale =  sensor.get_depth_scale();

Controlling the Laser

  • librealsense1:
rs::context ctx;
rs::device & dev = *ctx.get_device(0);

if (dev.supports_option(rs::option::r200_emitter_enabled)) // For R200 family
{
    dev.set_option(rs::option::r200_emitter_enabled, 1.f); // Enable laser emitter
    dev.set_option(rs::option::r200_emitter_enabled, 0.f); // Disable laser
}
if (dev.supports_option(rs::option::f200_laser_power)) // For F200 and SR300
{
    double min, max, step; // Query min and max values:
    dev.get_option_range(rs::option::f200_laser_power, min, max, step);
    dev.set_option(rs::option::f200_laser_power, max); // Enable laser (max power)
    dev.set_option(rs::option::f200_laser_power, 0.f); // Disable laser emitter
}
  • librealsense2:
rs2::pipeline pipe; 
rs2::pipeline_profile selection = pipe.start();
rs2::device selected_device = selection.get_device();
auto depth_sensor = selected_device.first<rs2::depth_sensor>();

if (depth_sensor.supports(RS2_OPTION_EMITTER_ENABLED))
{
    depth_sensor.set_option(RS2_OPTION_EMITTER_ENABLED, 1.f); // Enable emitter
    depth_sensor.set_option(RS2_OPTION_EMITTER_ENABLED, 0.f); // Disable emitter
}
if (depth_sensor.supports(RS2_OPTION_LASER_POWER))
{
    // Query min and max values:
    auto range = depth_sensor.get_option_range(RS2_OPTION_LASER_POWER);
    depth_sensor.set_option(RS2_OPTION_LASER_POWER, range.max); // Set max power
    depth_sensor.set_option(RS2_OPTION_LASER_POWER, 0.f); // Disable laser
}

Updated over 5 years ago