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OpenCV
4.5.2
Open Source Computer Vision
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An example using drawContours to clean up a background segmentation result
#include <stdio.h>
#include <string>
using namespace std;
static void help(char** argv)
{
printf("\n"
"This program demonstrated a simple method of connected components clean up of background subtraction\n"
"When the program starts, it begins learning the background.\n"
"You can toggle background learning on and off by hitting the space bar.\n"
"Call\n"
"%s [video file, else it reads camera 0]\n\n", argv[0]);
}
{
int niters = 3;
vector<vector<Point> > contours;
vector<Vec4i> hierarchy;
if( contours.size() == 0 )
return;
int idx = 0, largestComp = 0;
double maxArea = 0;
for( ; idx >= 0; idx = hierarchy[idx][0] )
{
const vector<Point>& c = contours[idx];
if( area > maxArea )
{
maxArea = area;
largestComp = idx;
}
}
}
int main(int argc, char** argv)
{
bool update_bg_model = true;
if (parser.has("help"))
{
help(argv);
return 0;
}
string input = parser.get<std::string>("@input");
if (input.empty())
else
{
printf("\nCan not open camera or video file\n");
return -1;
}
Mat tmp_frame, bgmask, out_frame;
cap >> tmp_frame;
if(tmp_frame.empty())
{
printf("can not read data from the video source\n");
return -1;
}
for(;;)
{
cap >> tmp_frame;
if( tmp_frame.empty() )
break;
bgsubtractor->
apply(tmp_frame, bgmask, update_bg_model ? -1 : 0);
refineSegments(tmp_frame, bgmask, out_frame);
imshow(
"segmented", out_frame);
if( keycode == 27 )
break;
if( keycode == ' ' )
{
update_bg_model = !update_bg_model;
printf("Learn background is in state = %d\n",update_bg_model);
}
}
return 0;
}
@ RETR_CCOMP
Definition: imgproc.hpp:428
void erode(InputArray src, OutputArray dst, InputArray kernel, Point anchor=Point(-1,-1), int iterations=1, int borderType=BORDER_CONSTANT, const Scalar &borderValue=morphologyDefaultBorderValue())
Erodes an image by using a specific structuring element.
virtual void apply(InputArray image, OutputArray fgmask, double learningRate=-1) CV_OVERRIDE=0
Computes a foreground mask.
Class for video capturing from video files, image sequences or cameras.
Definition: videoio.hpp:664
int waitKey(int delay=0)
Waits for a pressed key.
void namedWindow(const String &winname, int flags=WINDOW_AUTOSIZE)
Creates a window.
void findContours(InputArray image, OutputArrayOfArrays contours, OutputArray hierarchy, int mode, int method, Point offset=Point())
Finds contours in a binary image.
void dilate(InputArray src, OutputArray dst, InputArray kernel, Point anchor=Point(-1,-1), int iterations=1, int borderType=BORDER_CONSTANT, const Scalar &borderValue=morphologyDefaultBorderValue())
Dilates an image by using a specific structuring element.
#define CV_8UC3
Definition: interface.h:90
double contourArea(InputArray contour, bool oriented=false)
Calculates a contour area.
@ FILLED
Definition: imgproc.hpp:813
MatSize size
Definition: mat.hpp:2118
Ptr< BackgroundSubtractorMOG2 > createBackgroundSubtractorMOG2(int history=500, double varThreshold=16, bool detectShadows=true)
Creates MOG2 Background Subtractor.
virtual bool isOpened() const
Returns true if video capturing has been initialized already.
std::shared_ptr< _Tp > Ptr
Definition: cvstd_wrapper.hpp:23
void imshow(const String &winname, InputArray mat)
Displays an image in the specified window.
void drawContours(InputOutputArray image, InputArrayOfArrays contours, int contourIdx, const Scalar &color, int thickness=1, int lineType=LINE_8, InputArray hierarchy=noArray(), int maxLevel=INT_MAX, Point offset=Point())
Draws contours outlines or filled contours.
Point2i Point
Definition: types.hpp:194
virtual void setVarThreshold(double varThreshold)=0
Sets the variance threshold for the pixel-model match.
n-dimensional dense array class
Definition: mat.hpp:801
cv::String findFileOrKeep(const cv::String &relative_path, bool silentMode=false)
Definition: utility.hpp:1167
Designed for command line parsing.
Definition: utility.hpp:799
"black box" representation of the file storage associated with a file on disk.
Definition: affine.hpp:51
@ LINE_8
8-connected line
Definition: imgproc.hpp:815
@ CHAIN_APPROX_SIMPLE
Definition: imgproc.hpp:442
GMat mask(const GMat &src, const GMat &mask)
Applies a mask to a matrix.
virtual bool open(const String &filename, int apiPreference=CAP_ANY)
Opens a video file or a capturing device or an IP video stream for video capturing.