Mat GrimsonGMM::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::GrimsonParams params;
params.SetFrameSize(frame.cols, frame.rows);
params.LowThreshold() = parameters.get<float>("threshold");
params.HighThreshold() = parameters.get<float>("high_low_ratio")*params.LowThreshold();
params.Alpha() = parameters.get<float>("alpha");
params.MaxModes() = parameters.get<int>("max_modes");
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;
}
GrimsonParams CreateGrimsonGMMParams(int width, int height,
float low_threshold, float high_threshold,
float alpha, float max_modes)
{
Algorithms::BackgroundSubtraction::GrimsonParams params;
params.SetFrameSize(width, height);
params.LowThreshold() = low_threshold;
params.HighThreshold() = high_threshold;
params.Alpha() = alpha;
params.MaxModes() = max_modes;
return params;
}