Mat AdaptiveMedian::nextFrame(Context& context)
{
// Get frame
Mat frame = context.preproc_output;
// Read the image into frame_data
IplImage ipl_frame = frame;
frame_data = &ipl_frame;
// Check initialization
if(init)
{
// Set parameters
Algorithms::BackgroundSubtraction::AdaptiveMedianParams params;
params.SetFrameSize(frame.cols, frame.rows);
params.LowThreshold() = parameters.get<int>("threshold");
params.HighThreshold() = parameters.get<float>("high_low_ratio")*params.LowThreshold();
params.SamplingRate() = parameters.get<int>("sampling_rate");
params.LearningFrames() = parameters.get<int>("learning_frames");
bgs.Initalize(params);
// Initialize images
low_threshold_mask = cvCreateImage(cvSize(frame.cols, frame.rows), IPL_DEPTH_8U, 1);
high_threshold_mask = cvCreateImage(cvSize(frame.cols, frame.rows), IPL_DEPTH_8U, 1);
frame_data.ReleaseMemory(false);
// Initialize model
bgs.InitModel(frame_data);
// Clear flag
init = false;
}
// Perform background subtraction
bgs.Subtract(context.frame_num, frame_data, low_threshold_mask, high_threshold_mask);
// Convert motion mask to Mat
Mat bkg_sub(low_threshold_mask.Ptr(), true);
// Remove isolated white pixels
Mat median_out;
medianBlur(bkg_sub, median_out, 3);
// Show image
//imshow("segm", median_out);
//waitKey(0);
// Set to context and return
context.motion_output = median_out;
return median_out;
}
AdaptiveMedianParams CreateAdaptiveMedianParams(int width, int height,
float low_threshold, float high_threshold,
int sampling_rate, int learning_frames)
{
Algorithms::BackgroundSubtraction::AdaptiveMedianParams params;
params.SetFrameSize(width, height);
params.LowThreshold() = low_threshold;
params.HighThreshold() = high_threshold;
params.SamplingRate() = sampling_rate;
params.LearningFrames() = learning_frames;
return params;
}
int main(int argc, const char* argv[])
{
// read data from AVI file
CvCapture* readerAvi = cvCaptureFromFile(argv[1]);
if(readerAvi == NULL)
{
std::cerr << "Could not open AVI file." << std::endl;
return 0;
}
// retrieve information about AVI file
cvQueryFrame(readerAvi);
int width = (int) cvGetCaptureProperty(readerAvi, CV_CAP_PROP_FRAME_WIDTH);
int height = (int) cvGetCaptureProperty(readerAvi, CV_CAP_PROP_FRAME_HEIGHT);
int fps = (int) cvGetCaptureProperty(readerAvi, CV_CAP_PROP_FPS);
int num_frames = (unsigned int) cvGetCaptureProperty(readerAvi, CV_CAP_PROP_FRAME_COUNT);
// setup marks to hold results of low and high thresholding
BwImage low_threshold_mask = cvCreateImage(cvSize(width, height), IPL_DEPTH_8U, 1);
low_threshold_mask.Ptr()->origin = IPL_ORIGIN_BL;
BwImage high_threshold_mask = cvCreateImage(cvSize(width, height), IPL_DEPTH_8U, 1);
high_threshold_mask.Ptr()->origin = IPL_ORIGIN_BL;
// setup buffer to hold individual frames from video stream
RgbImage frame_data;
frame_data.ReleaseMemory(false); // AVI frame data is released by with the AVI capture device
// setup AVI writers (note: you will need to install the HUFFY codex at:
// http://neuron2.net/www.math.berkeley.edu/benrg/huffyuv.html)
CvVideoWriter* writerAvi = cvCreateVideoWriter("results.avi", CV_FOURCC('H', 'F', 'Y', 'U'),
fps, cvSize(width, height), 1);
// setup background subtraction algorithm
Algorithms::BackgroundSubtraction::AdaptiveMedianParams params;
params.SetFrameSize(width, height);
params.LowThreshold() = 40;
params.HighThreshold() = 2*params.LowThreshold(); // Note: high threshold is used by post-processing
params.SamplingRate() = 7;
params.LearningFrames() = 30;
Algorithms::BackgroundSubtraction::AdaptiveMedianBGS bgs;
bgs.Initalize(params);
/*
Algorithms::BackgroundSubtraction::GrimsonParams params;
params.SetFrameSize(width, height);
params.LowThreshold() = 3.0f*3.0f;
params.HighThreshold() = 2*params.LowThreshold(); // Note: high threshold is used by post-processing
params.Alpha() = 0.001f;
params.MaxModes() = 3;
Algorithms::BackgroundSubtraction::GrimsonGMM bgs;
bgs.Initalize(params);
*/
/*
Algorithms::BackgroundSubtraction::ZivkovicParams params;
params.SetFrameSize(width, height);
params.LowThreshold() = 5.0f*5.0f;
params.HighThreshold() = 2*params.LowThreshold(); // Note: high threshold is used by post-processing
params.Alpha() = 0.001f;
params.MaxModes() = 3;
Algorithms::BackgroundSubtraction::ZivkovicAGMM bgs;
bgs.Initalize(params);
*/
/*
Algorithms::BackgroundSubtraction::MeanParams params;
params.SetFrameSize(width, height);
params.LowThreshold() = 3*30*30;
params.HighThreshold() = 2*params.LowThreshold(); // Note: high threshold is used by post-processing
params.Alpha() = 1e-6f;
params.LearningFrames() = 30;
Algorithms::BackgroundSubtraction::MeanBGS bgs;
bgs.Initalize(params);
*/
/*
Algorithms::BackgroundSubtraction::WrenParams params;
params.SetFrameSize(width, height);
params.LowThreshold() = 3.5f*3.5f;
params.HighThreshold() = 2*params.LowThreshold(); // Note: high threshold is used by post-processing
params.Alpha() = 0.005f;
params.LearningFrames() = 30;
Algorithms::BackgroundSubtraction::WrenGA bgs;
bgs.Initalize(params);
*/
/*
Algorithms::BackgroundSubtraction::PratiParams params;
params.SetFrameSize(width, height);
params.LowThreshold() = 30;
params.HighThreshold() = 2*params.LowThreshold(); // Note: high threshold is used by post-processing
params.SamplingRate() = 5;
params.HistorySize() = 16;
params.Weight() = 5;
Algorithms::BackgroundSubtraction::PratiMediodBGS bgs;
bgs.Initalize(params);
*/
/*
Algorithms::BackgroundSubtraction::EigenbackgroundParams params;
params.SetFrameSize(width, height);
params.LowThreshold() = 15*15;
params.HighThreshold() = 2*params.LowThreshold(); // Note: high threshold is used by post-processing
params.HistorySize() = 100;
params.EmbeddedDim() = 20;
Algorithms::BackgroundSubtraction::Eigenbackground bgs;
bgs.Initalize(params);
*/
// perform background subtraction of each frame
for(int i = 0; i < num_frames-1; ++i)
{
if(i % 100 == 0)
std::cout << "Processing frame " << i << " of " << num_frames << "..." << std::endl;
// grad next frame from input video stream
if(!cvGrabFrame(readerAvi))
{
std::cerr << "Could not grab AVI frame." << std::endl;
return 0;
}
frame_data = cvRetrieveFrame(readerAvi);
cvShowImage("aa", frame_data.Ptr());
// initialize background model to first frame of video stream
if (i == 0)
bgs.InitModel(frame_data);
// perform background subtraction
bgs.Subtract(i, frame_data, low_threshold_mask, high_threshold_mask);
cvShowImage("bb", low_threshold_mask.Ptr());
waitKey(0);
// save results
cvWriteFrame(writerAvi, low_threshold_mask.Ptr());
// update background subtraction
low_threshold_mask.Clear(); // disable conditional updating
bgs.Update(i, frame_data, low_threshold_mask);
}
cvReleaseCapture(&readerAvi);
cvReleaseVideoWriter(&writerAvi);
}