alprstream_images.cpp

// OpenALPR sample for alprstreamgpu library
// Copyright 2017, OpenALPR Technology, Inc.

// System imports
#include <cstdlib>
#include <vector>
#include <string>
#include <string.h>
#include <sstream>

// Import used to list files in directory
#include <dirent.h>

#include <opencv2/opencv.hpp>
#include <opencv2/highgui/highgui.hpp>

// Import OpenALPR alprstreamgpu (also pulls in alprgpu.h and alpr.h)
// Object definitions for individual results are found in alpr.h
// Object definitions for group results are found in alprstreamgpu.h
#include <alprstream.h>

using namespace std;
using namespace alpr;

// helper prototypes
std::vector<std::string> list_files_in_dir(const char* dirPath);
void print_frame_results(vector<RecognizedFrame> rframes);
void print_group_results(std::vector<AlprGroupResult> groups);


int main(int argc, char** argv) {

  cout << "Initializing" << endl;
  const long STARTING_EPOCH_TIME_MS = 1500294710000;
  const std::string LICENSEPLATE_COUNTRY = "us";
  
  
  // Size of image buffer to maintain in stream queue -- This only matters if you are feeding
  // images/video into the buffer faster than can be processed (i.e., on a background thread)
  // Setting this to the batch size since we're feeding in images synchronously, so it's only needed to 
  // hold a single batch

  // Batch size and GPU ID set in openalpr.conf
  // Video buffer frames controls the number of frames to buffer in memory.  Must be >= gpu batch size
  const int VIDEO_BUFFER_SIZE = 15;
  
  // The stream will assume sequential frames.  If there is no motion from frame to frame, then 
  // processing can be skipped for some frames
  const bool USE_MOTION_DETECTION = false;

  AlprStream alpr_stream(VIDEO_BUFFER_SIZE, USE_MOTION_DETECTION);
  Alpr alpr(LICENSEPLATE_COUNTRY, "", "", "SEpKS0xNTkewsbKztLW2t7i5uru8vb7C2Nje36WgpaetqqOvpaqvqpORl5CdkZ+QAHddFHPee9CiEPnPDHq90vCB7TcEJPm0Gq7MdB/0jGqrJmBzTXii59+J12zZ7GfsRL+a1VqbuOWZM+fkI3PoXzw53kOuwEr0RcEnEfFu8kXh8546xlSRYQSwoKoq84/B");

  cout << "Initialization complete" << endl;

  // It's important that the image dimensions are consistent within a batch and that you 
  // only drive OpenALPR with few various image sizes.  The memory for each image size is 
  // cached on the GPU for efficiency, and using many different image sizes will degrade performance
  vector<string> input_images = list_files_in_dir("/tmp/imagebatchtest");
  
  for (uint32_t i = 0; i < input_images.size(); i++)
  {
    cout << "Batching image " << i << ": " << input_images[i] << endl;
    
    cv::Mat img = cv::imread(input_images[i], 1);
    
    // Push the raw BGR pixel data
    // Use the arbitrary starting epoch time + 100ms for each image
    alpr_stream.push_frame(img.data, img.elemSize(), img.cols, img.rows, STARTING_EPOCH_TIME_MS + (i * 100));

    int BATCH_SIZE = 10;
    if (alpr_stream.get_queue_size() >= BATCH_SIZE || i == input_images.size()-1)
    {
      // Process a batch once the stream is full or it's the last image

      vector<RecognizedFrame> frame_results = alpr_stream.process_batch(&alpr);
      print_frame_results(frame_results);
      
      // After each batch processing, we can check to see if any groups are ready
      // "Groups" form based on their timestamp and plate numbers on each stream
      // The stream object has configurable options for how long to wait before 
      // completing a plate group.  You may peek at the active list without popping.
      cout << "After batching there are: " << alpr_stream.peek_active_groups().size() << " active groups" << endl;
      
      std::vector<AlprGroupResult> group_results = alpr_stream.pop_completed_groups();
      print_group_results(group_results);
    }
  }
  
  cout << "Done" << endl;
  
  return 0;
}



void print_frame_results(vector<RecognizedFrame> rframes)
{
  for (uint32_t frame_index = 0; frame_index < rframes.size(); frame_index++)
  {
    RecognizedFrame rf = rframes[frame_index];
    for (uint32_t i = 0; i < rf.results.plates.size(); i++)
    {
      cout << "Frame " << rf.frame_number << " result: " << rf.results.plates[i].bestPlate.characters << endl;
    }
  }
}

void print_group_results(std::vector<AlprGroupResult> groups)
{
  for (uint32_t group_index = 0; group_index < groups.size(); group_index++)
  {
    AlprGroupResult group = groups[group_index];

    cout << "Group (" << group.epoch_ms_time_start << " - " << group.epoch_ms_time_end << ") " << group.best_plate_number << endl;
  }
}

std::vector<std::string> list_files_in_dir(const char* dirPath)
{
  DIR *dir;

  std::vector<std::string> files;

  struct dirent *ent;
  if ((dir = opendir (dirPath)) != NULL)
  {
    /* print all the files and directories within directory */
    while ((ent = readdir (dir)) != NULL)
    {
      if (strcmp(ent->d_name, ".") != 0 && strcmp(ent->d_name, "..") != 0)
      {
        stringstream fullpath;
        fullpath << dirPath << "/" << ent->d_name;
        files.push_back(fullpath.str());
      }
    }
    closedir (dir);
  }
  else
  {
    /* could not open directory */
    perror ("");
    return files;
  }

  return files;
}