crop_decimate.cpp

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#include <boost/version.hpp>
#if ((BOOST_VERSION / 100) % 1000) >= 53
#include <boost/thread/lock_guard.hpp>
#endif

#include <ros/ros.h>
#include <nodelet/nodelet.h>
#include <image_transport/image_transport.h>
#include <sensor_msgs/image_encodings.h>
#include <dynamic_reconfigure/server.h>
#include <cv_bridge/cv_bridge.h>
#include <image_proc/CropDecimateConfig.h>
#include <opencv2/imgproc/imgproc.hpp>

namespace image_proc {

using namespace cv_bridge; // CvImage, toCvShare

class CropDecimateNodelet : public nodelet::Nodelet
{
  // ROS communication
  boost::shared_ptr<image_transport::ImageTransport> it_in_, it_out_;
  image_transport::CameraSubscriber sub_;
  int queue_size_;
  std::string target_frame_id_;

  boost::mutex connect_mutex_;
  image_transport::CameraPublisher pub_;

  // Dynamic reconfigure
  boost::recursive_mutex config_mutex_;
  typedef image_proc::CropDecimateConfig Config;
  typedef dynamic_reconfigure::Server<Config> ReconfigureServer;
  boost::shared_ptr<ReconfigureServer> reconfigure_server_;
  Config config_;

  virtual void onInit();

  void connectCb();

  void imageCb(const sensor_msgs::ImageConstPtr& image_msg,
               const sensor_msgs::CameraInfoConstPtr& info_msg);

  void configCb(Config &config, uint32_t level);
};

void CropDecimateNodelet::onInit()
{
  ros::NodeHandle& nh         = getNodeHandle();
  ros::NodeHandle& private_nh = getPrivateNodeHandle();
  ros::NodeHandle nh_in (nh, "camera");
  ros::NodeHandle nh_out(nh, "camera_out");
  it_in_ .reset(new image_transport::ImageTransport(nh_in));
  it_out_.reset(new image_transport::ImageTransport(nh_out));

  // Read parameters
  private_nh.param("queue_size", queue_size_, 5);
  private_nh.param("target_frame_id", target_frame_id_, std::string());

  // Set up dynamic reconfigure
  reconfigure_server_.reset(new ReconfigureServer(config_mutex_, private_nh));
  ReconfigureServer::CallbackType f = boost::bind(&CropDecimateNodelet::configCb, this, _1, _2);
  reconfigure_server_->setCallback(f);

  // Monitor whether anyone is subscribed to the output
  image_transport::SubscriberStatusCallback connect_cb = boost::bind(&CropDecimateNodelet::connectCb, this);
  ros::SubscriberStatusCallback connect_cb_info = boost::bind(&CropDecimateNodelet::connectCb, this);
  // Make sure we don't enter connectCb() between advertising and assigning to pub_
  boost::lock_guard<boost::mutex> lock(connect_mutex_);
  pub_ = it_out_->advertiseCamera("image_raw",  1, connect_cb, connect_cb, connect_cb_info, connect_cb_info);
}

// Handles (un)subscribing when clients (un)subscribe
void CropDecimateNodelet::connectCb()
{
  boost::lock_guard<boost::mutex> lock(connect_mutex_);
  if (pub_.getNumSubscribers() == 0)
    sub_.shutdown();
  else if (!sub_)
  {
    image_transport::TransportHints hints("raw", ros::TransportHints(), getPrivateNodeHandle());
    sub_ = it_in_->subscribeCamera("image_raw", queue_size_, &CropDecimateNodelet::imageCb, this, hints);
  }
}

template <typename T>
void debayer2x2toBGR(const cv::Mat& src, cv::Mat& dst, int R, int G1, int G2, int B)
{
  typedef cv::Vec<T, 3> DstPixel; // 8- or 16-bit BGR
  dst.create(src.rows / 2, src.cols / 2, cv::DataType<DstPixel>::type);

  int src_row_step = src.step1();
  int dst_row_step = dst.step1();
  const T* src_row = src.ptr<T>();
  T* dst_row = dst.ptr<T>();

  // 2x2 downsample and debayer at once
  for (int y = 0; y < dst.rows; ++y)
  {
    for (int x = 0; x < dst.cols; ++x)
    {
      dst_row[x*3 + 0] = src_row[x*2 + B];
      dst_row[x*3 + 1] = (src_row[x*2 + G1] + src_row[x*2 + G2]) / 2;
      dst_row[x*3 + 2] = src_row[x*2 + R];
    }
    src_row += src_row_step * 2;
    dst_row += dst_row_step;
  }
}

// Templated on pixel size, in bytes (MONO8 = 1, BGR8 = 3, RGBA16 = 8, ...)
template <int N>
void decimate(const cv::Mat& src, cv::Mat& dst, int decimation_x, int decimation_y)
{
  dst.create(src.rows / decimation_y, src.cols / decimation_x, src.type());

  int src_row_step = src.step[0] * decimation_y;
  int src_pixel_step = N * decimation_x;
  int dst_row_step = dst.step[0];

  const uint8_t* src_row = src.ptr();
  uint8_t* dst_row = dst.ptr();
  
  for (int y = 0; y < dst.rows; ++y)
  {
    const uint8_t* src_pixel = src_row;
    uint8_t* dst_pixel = dst_row;
    for (int x = 0; x < dst.cols; ++x)
    {
      memcpy(dst_pixel, src_pixel, N); // Should inline with small, fixed N
      src_pixel += src_pixel_step;
      dst_pixel += N;
    }
    src_row += src_row_step;
    dst_row += dst_row_step;
  }
}

void CropDecimateNodelet::imageCb(const sensor_msgs::ImageConstPtr& image_msg,
                                  const sensor_msgs::CameraInfoConstPtr& info_msg)
{

  Config config;
  {
    boost::lock_guard<boost::recursive_mutex> lock(config_mutex_);
    config = config_;
  }
  int decimation_x = config.decimation_x;
  int decimation_y = config.decimation_y;

  // Compute the ROI we'll actually use
  bool is_bayer = sensor_msgs::image_encodings::isBayer(image_msg->encoding);
  if (is_bayer)
  {
    // Odd offsets for Bayer images basically change the Bayer pattern, but that's
    // unnecessarily complicated to support
    config.x_offset &= ~0x1;
    config.y_offset &= ~0x1;
    config.width &= ~0x1;
    config.height &= ~0x1;    
  }

  int max_width = image_msg->width - config.x_offset;
  int max_height = image_msg->height - config.y_offset;
  int width = config.width;
  int height = config.height;
  if (width == 0 || width > max_width)
    width = max_width;
  if (height == 0 || height > max_height)
    height = max_height;

  // On no-op, just pass the messages along
  if (decimation_x == 1               &&
      decimation_y == 1               &&
      config.x_offset == 0            &&
      config.y_offset == 0            &&
      width  == (int)image_msg->width &&
      height == (int)image_msg->height)
  {
    pub_.publish(image_msg, info_msg);
    return;
  }

  // Get a cv::Mat view of the source data
  CvImageConstPtr source = toCvShare(image_msg);

  // Except in Bayer downsampling case, output has same encoding as the input
  CvImage output(source->header, source->encoding);
  // Apply ROI (no copy, still a view of the image_msg data)
  output.image = source->image(cv::Rect(config.x_offset, config.y_offset, width, height));

  // Special case: when decimating Bayer images, we first do a 2x2 decimation to BGR
  if (is_bayer && (decimation_x > 1 || decimation_y > 1))
  {
    if (decimation_x % 2 != 0 || decimation_y % 2 != 0)
    {
      NODELET_ERROR_THROTTLE(2, "Odd decimation not supported for Bayer images");
      return;
    }

    cv::Mat bgr;
    int step = output.image.step1();
    if (image_msg->encoding == sensor_msgs::image_encodings::BAYER_RGGB8)
      debayer2x2toBGR<uint8_t>(output.image, bgr, 0, 1, step, step + 1);
    else if (image_msg->encoding == sensor_msgs::image_encodings::BAYER_BGGR8)
      debayer2x2toBGR<uint8_t>(output.image, bgr, step + 1, 1, step, 0);
    else if (image_msg->encoding == sensor_msgs::image_encodings::BAYER_GBRG8)
      debayer2x2toBGR<uint8_t>(output.image, bgr, step, 0, step + 1, 1);
    else if (image_msg->encoding == sensor_msgs::image_encodings::BAYER_GRBG8)
      debayer2x2toBGR<uint8_t>(output.image, bgr, 1, 0, step + 1, step);
    else if (image_msg->encoding == sensor_msgs::image_encodings::BAYER_RGGB16)
      debayer2x2toBGR<uint16_t>(output.image, bgr, 0, 1, step, step + 1);
    else if (image_msg->encoding == sensor_msgs::image_encodings::BAYER_BGGR16)
      debayer2x2toBGR<uint16_t>(output.image, bgr, step + 1, 1, step, 0);
    else if (image_msg->encoding == sensor_msgs::image_encodings::BAYER_GBRG16)
      debayer2x2toBGR<uint16_t>(output.image, bgr, step, 0, step + 1, 1);
    else if (image_msg->encoding == sensor_msgs::image_encodings::BAYER_GRBG16)
      debayer2x2toBGR<uint16_t>(output.image, bgr, 1, 0, step + 1, step);
    else
    {
      NODELET_ERROR_THROTTLE(2, "Unrecognized Bayer encoding '%s'", image_msg->encoding.c_str());
      return;
    }

    output.image = bgr;
    output.encoding = (bgr.depth() == CV_8U) ? sensor_msgs::image_encodings::BGR8
                                             : sensor_msgs::image_encodings::BGR16;
    decimation_x /= 2;
    decimation_y /= 2;
  }

  // Apply further downsampling, if necessary
  if (decimation_x > 1 || decimation_y > 1)
  {
    cv::Mat decimated;

    if (config.interpolation == image_proc::CropDecimate_NN)
    {
      // Use optimized method instead of OpenCV's more general NN resize
      int pixel_size = output.image.elemSize();
      switch (pixel_size)
      {
        // Currently support up through 4-channel float
        case 1:
          decimate<1>(output.image, decimated, decimation_x, decimation_y);
          break;
        case 2:
          decimate<2>(output.image, decimated, decimation_x, decimation_y);
          break;
        case 3:
          decimate<3>(output.image, decimated, decimation_x, decimation_y);
          break;
        case 4:
          decimate<4>(output.image, decimated, decimation_x, decimation_y);
          break;
        case 6:
          decimate<6>(output.image, decimated, decimation_x, decimation_y);
          break;
        case 8:
          decimate<8>(output.image, decimated, decimation_x, decimation_y);
          break;
        case 12:
          decimate<12>(output.image, decimated, decimation_x, decimation_y);
          break;
        case 16:
          decimate<16>(output.image, decimated, decimation_x, decimation_y);
          break;
        default:
          NODELET_ERROR_THROTTLE(2, "Unsupported pixel size, %d bytes", pixel_size);
          return;
      }
    }
    else
    {
      // Linear, cubic, area, ...
      cv::Size size(output.image.cols / decimation_x, output.image.rows / decimation_y);
      cv::resize(output.image, decimated, size, 0.0, 0.0, config.interpolation);
    }

    output.image = decimated;
  }

  // Create output Image message
  sensor_msgs::ImagePtr out_image = output.toImageMsg();

  // Create updated CameraInfo message
  sensor_msgs::CameraInfoPtr out_info = boost::make_shared<sensor_msgs::CameraInfo>(*info_msg);
  int binning_x = std::max((int)info_msg->binning_x, 1);
  int binning_y = std::max((int)info_msg->binning_y, 1);
  out_info->binning_x = binning_x * config.decimation_x;
  out_info->binning_y = binning_y * config.decimation_y;
  out_info->roi.x_offset += config.x_offset * binning_x;
  out_info->roi.y_offset += config.y_offset * binning_y;
  out_info->roi.height = height * binning_y;
  out_info->roi.width = width * binning_x;
  // If no ROI specified, leave do_rectify as-is. If ROI specified, set do_rectify = true.
  if (width != (int)image_msg->width || height != (int)image_msg->height)
    out_info->roi.do_rectify = true;

  if (!target_frame_id_.empty()) {
    out_image->header.frame_id = target_frame_id_;
    out_info->header.frame_id = target_frame_id_;
  }

  pub_.publish(out_image, out_info);
}

void CropDecimateNodelet::configCb(Config &config, uint32_t level)
{
  config_ = config;
}

} // namespace image_proc

// Register nodelet
#include <pluginlib/class_list_macros.h>
PLUGINLIB_EXPORT_CLASS( image_proc::CropDecimateNodelet, nodelet::Nodelet)