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#include <esim.h>
#include <fstream>
#include <iostream>
#include <algorithm>
#include <opencv2/core/eigen.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
EventSimulator::EventSimulator(float contrast_threshold_pos,
float contrast_threshold_neg,
float refractory_period,
float log_eps,
bool use_log_img)
: contrast_threshold_pos_(contrast_threshold_pos), contrast_threshold_neg_(contrast_threshold_neg),
refractory_period_(refractory_period), log_eps_(log_eps), use_log_img_(use_log_img), is_initialized_(false)
{
}
Eigen::MatrixXd EventSimulator::generateFromVideo(std::string video_path, std::string timestamps_file_path)
{
std::ifstream timestamps_file(timestamps_file_path);
if(!timestamps_file.is_open())
throw std::runtime_error("unable to open the file " + timestamps_file_path);
cv::VideoCapture cap(video_path);
if ( !cap.isOpened() )
throw std::runtime_error("Cannot open the video file " + video_path);
std::string time_str;
double time;
std::vector<Event> events_vec;
cv::Mat img, log_img;
while (cap.read(img))
{
img.convertTo(img, CV_32F, 1.0/255);
cv::Mat log_img = img;
if (use_log_img_)
cv::log(img+log_eps_, log_img);
std::getline(timestamps_file, time_str);
time = std::stod(time_str);
imageCallback(log_img, time, events_vec);
}
// reset state to generate new events
is_initialized_ = false;
return vec_to_eigen_matrix(events_vec);
}
Eigen::MatrixXd EventSimulator::generateFromStampedImageSequence(std::vector<std::string> image_paths, std::vector<double> timestamps)
{
// check that timestamps are ascending
if (image_paths.size() != timestamps.size())
throw std::runtime_error("Number of image paths and number of timestamps should be equal. Got " + std::to_string(image_paths.size()) + " and " + std::to_string(timestamps.size()));
cv::Mat img, log_img;
double time;
std::vector<Event> events_vec;
for (int i=0; i<timestamps.size(); i++)
{
if ((i < timestamps.size()-1) && timestamps[i+1]<timestamps[i])
throw std::runtime_error("Timestamps must be sorted in ascending order.");
img = cv::imread(image_paths[i], cv::IMREAD_GRAYSCALE);
if(img.empty())
throw std::runtime_error("unable to open the image " + image_paths[i]);
img.convertTo(img, CV_32F, 1.0/255);
cv::Mat log_img = img;
if (use_log_img_)
cv::log(img+log_eps_, log_img);
time = timestamps[i];
imageCallback(log_img, time, events_vec);
}
// reset state to generate new events
is_initialized_ = false;
return vec_to_eigen_matrix(events_vec);
}
Eigen::MatrixXd EventSimulator::generateFromFolder(std::string image_folder, std::string timestamps_file_path)
{
std::vector<std::string> image_files;
read_directory_from_path(image_folder, image_files);
std::ifstream timestamps_file(timestamps_file_path);
if(!timestamps_file.is_open())
throw std::runtime_error("unable to open the file " + timestamps_file_path);
std::string time_str;
double time;
std::vector<Event> events_vec;
cv::Mat img, log_img;
for (const std::string& file : image_files)
{
img = cv::imread(file, cv::IMREAD_GRAYSCALE);
if(img.empty())
throw std::runtime_error("unable to open the image " + file);
img.convertTo(img, CV_32F, 1.0/255);
cv::Mat log_img = img;
if (use_log_img_)
cv::log(img+log_eps_, log_img);
std::getline(timestamps_file, time_str);
time = std::stod(time_str);
imageCallback(log_img, time, events_vec);
}
// reset state to generate new events
is_initialized_ = false;
return vec_to_eigen_matrix(events_vec);
}
void EventSimulator::initialise(py::array_t<float> input_array, double time) {
cv::Mat img = pyArrayToCvMat(input_array);
init(img, time);
}
Eigen::MatrixXd EventSimulator::generateEventFromCVImage(py::array_t<float> input_array, double time) {
cv::Mat log_img = pyArrayToCvMat(input_array);
std::vector<Event> events_vec;
imageCallback(log_img, time, events_vec);
return vec_to_eigen_matrix(events_vec);
}
void EventSimulator::init(const cv::Mat &img, double time)
{
is_initialized_ = true;
last_img_ = img;
ref_values_ = img;
last_event_timestamp_ = cv::Mat::zeros(img.size[0], img.size[1], CV_64F);
current_time_ = time;
image_width_ = img.size[1];
image_height_ = img.size[0];
}
void EventSimulator::imageCallback(const cv::Mat& img, double time, std::vector<Event>& events)
{
cv::Mat preprocessed_img = img;
if(!is_initialized_)
{
init(preprocessed_img, time);
return;
}
std::vector<Event> new_events;
static constexpr double kTolerance = 1e-6;
double delta_t = time - current_time_;
for (int y = 0; y < image_height_; ++y)
{
for (int x = 0; x < image_width_; ++x)
{
float& itdt = preprocessed_img.at<float>(y, x);
float& it = last_img_.at<float>(y, x);
float& prev_cross = ref_values_.at<float>(y, x);
if (std::fabs (it - itdt) > kTolerance)
{
float pol = (itdt >= it) ? +1.0 : -1.0;
float C = (pol > 0) ? contrast_threshold_pos_ : contrast_threshold_neg_;
float curr_cross = prev_cross;
bool all_crossings = false;
do
{
curr_cross += pol * C;
if ((pol > 0 && curr_cross > it && curr_cross <= itdt)
|| (pol < 0 && curr_cross < it && curr_cross >= itdt))
{
const double edt = (curr_cross - it) * delta_t / (itdt - it);
const double t = current_time_ + edt;
const double last_stamp_at_xy = last_event_timestamp_.at<double>(y,x);
const double dt = t - last_stamp_at_xy;
if(last_stamp_at_xy == 0 || dt >= refractory_period_)
{
new_events.emplace_back(x, y,t,pol);
last_event_timestamp_.at<double>(y,x) = t;
}
ref_values_.at<float>(y,x) = curr_cross;
}
else
{
all_crossings = true;
}
} while (!all_crossings);
} // end tolerance
} // end for each pixel
}
current_time_ = time;
last_img_ = preprocessed_img; // it is now the latest image
// need to sort the new events before inserting
std::sort(new_events.begin(), new_events.end());
events.insert(events.end(), new_events.begin(), new_events.end());
}
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