问题描述
我的工作运动检测与使用OpenCV的非静态相机。
我使用的是pretty基本背景减法和阈值的方法来获得所有的广义上的移动在样品视频。阈值后，我争取白色像素可分离所有补丁，将它们保存为独立的组件，并用红，绿，蓝颜色随机他们。下图显示了这一段视频的足球，所有这些部件都是可见的。
I am working on motion detection with non-static camera using opencv.I am using a pretty basic background subtraction and thresholding approach to get a broad sense of all that's moving in a sample video. After thresholding, I enlist all separable "patches" of white pixels, store them as independent components and color them randomly with red, green or blue. The image below shows this for a football video where all such components are visible.
我创建了这些检测组件矩形和我得到这个图片：
I create rectangles over these detected components and I get this image:
所以，我可以看到这里的挑战。我想所有群集相似和近用部件成一个单一的实体，以使输出图像中的矩形示出了播放器移动作为一个整体（而不是他的独立肢体）。我试着做K-均值聚类但由于理想我不知道移动实体的数目，我无法取得任何进展。
So I can see the challenge here. I want to cluster all the "similar" and close-by components into a single entity so that the rectangles in the output image show a player moving as a whole (and not his independent limbs). I tried doing K-means clustering but since ideally I would not know the number of moving entities, I could not make any progress.
请指导我怎么能做到这一点。谢谢
Please guide me on how I can do this. Thanks
推荐答案
这个问题可以通过DBSCAN聚类算法几乎可以完美解决。下面，我提供的实施和结果图像。灰色的斑点是指根据DBSCAN异常或噪音。我只是用箱作为输入数据。最初，用于距离函数框中心。然而对于盒，它不足以正确地表征的距离。那么，目前距离函数使用两盒所有8个角的最小距离。
this problem can be almost perfectly solved by dbscan clustering algorithm. Below, I provide the implementation and result image. Gray blob means outlier or noise according to dbscan. I simply used boxes as input data. Initially, box centers were used for distance function. However for boxes, it is insufficient to correctly characterize distance. So, the current distance function use the minimum distance of all 8 corners of two boxes.
#include "opencv2/opencv.hpp"
using namespace cv;
#include <map>
#include <sstream>
template <class T>
inline std::string to_string (const T& t)
{
std::stringstream ss;
ss << t;
return ss.str();
}
class DbScan
{
public:
std::map<int, int> labels;
vector<Rect>& data;
int C;
double eps;
int mnpts;
double* dp;
//memoization table in case of complex dist functions
#define DP(i,j) dp[(data.size()*i)+j]
DbScan(vector<Rect>& _data,double _eps,int _mnpts):data(_data)
{
C=-1;
for(int i=0;i<data.size();i++)
{
labels[i]=-99;
}
eps=_eps;
mnpts=_mnpts;
}
void run()
{
dp = new double[data.size()*data.size()];
for(int i=0;i<data.size();i++)
{
for(int j=0;j<data.size();j++)
{
if(i==j)
DP(i,j)=0;
else
DP(i,j)=-1;
}
}
for(int i=0;i<data.size();i++)
{
if(!isVisited(i))
{
vector<int> neighbours = regionQuery(i);
if(neighbours.size()<mnpts)
{
labels[i]=-1;//noise
}else
{
C++;
expandCluster(i,neighbours);
}
}
}
delete [] dp;
}
void expandCluster(int p,vector<int> neighbours)
{
labels[p]=C;
for(int i=0;i<neighbours.size();i++)
{
if(!isVisited(neighbours[i]))
{
labels[neighbours[i]]=C;
vector<int> neighbours_p = regionQuery(neighbours[i]);
if (neighbours_p.size() >= mnpts)
{
expandCluster(neighbours[i],neighbours_p);
}
}
}
}
bool isVisited(int i)
{
return labels[i]!=-99;
}
vector<int> regionQuery(int p)
{
vector<int> res;
for(int i=0;i<data.size();i++)
{
if(distanceFunc(p,i)<=eps)
{
res.push_back(i);
}
}
return res;
}
double dist2d(Point2d a,Point2d b)
{
return sqrt(pow(a.x-b.x,2) + pow(a.y-b.y,2));
}
double distanceFunc(int ai,int bi)
{
if(DP(ai,bi)!=-1)
return DP(ai,bi);
Rect a = data[ai];
Rect b = data[bi];
/*
Point2d cena= Point2d(a.x+a.width/2,
a.y+a.height/2);
Point2d cenb = Point2d(b.x+b.width/2,
b.y+b.height/2);
double dist = sqrt(pow(cena.x-cenb.x,2) + pow(cena.y-cenb.y,2));
DP(ai,bi)=dist;
DP(bi,ai)=dist;*/
Point2d tla =Point2d(a.x,a.y);
Point2d tra =Point2d(a.x+a.width,a.y);
Point2d bla =Point2d(a.x,a.y+a.height);
Point2d bra =Point2d(a.x+a.width,a.y+a.height);
Point2d tlb =Point2d(b.x,b.y);
Point2d trb =Point2d(b.x+b.width,b.y);
Point2d blb =Point2d(b.x,b.y+b.height);
Point2d brb =Point2d(b.x+b.width,b.y+b.height);
double minDist = 9999999;
minDist = min(minDist,dist2d(tla,tlb));
minDist = min(minDist,dist2d(tla,trb));
minDist = min(minDist,dist2d(tla,blb));
minDist = min(minDist,dist2d(tla,brb));
minDist = min(minDist,dist2d(tra,tlb));
minDist = min(minDist,dist2d(tra,trb));
minDist = min(minDist,dist2d(tra,blb));
minDist = min(minDist,dist2d(tra,brb));
minDist = min(minDist,dist2d(bla,tlb));
minDist = min(minDist,dist2d(bla,trb));
minDist = min(minDist,dist2d(bla,blb));
minDist = min(minDist,dist2d(bla,brb));
minDist = min(minDist,dist2d(bra,tlb));
minDist = min(minDist,dist2d(bra,trb));
minDist = min(minDist,dist2d(bra,blb));
minDist = min(minDist,dist2d(bra,brb));
DP(ai,bi)=minDist;
DP(bi,ai)=minDist;
return DP(ai,bi);
}
vector<vector<Rect> > getGroups()
{
vector<vector<Rect> > ret;
for(int i=0;i<=C;i++)
{
ret.push_back(vector<Rect>());
for(int j=0;j<data.size();j++)
{
if(labels[j]==i)
{
ret[ret.size()-1].push_back(data[j]);
}
}
}
return ret;
}
};
cv::Scalar HSVtoRGBcvScalar(int H, int S, int V) {
int bH = H; // H component
int bS = S; // S component
int bV = V; // V component
double fH, fS, fV;
double fR, fG, fB;
const double double_TO_BYTE = 255.0f;
const double BYTE_TO_double = 1.0f / double_TO_BYTE;
// Convert from 8-bit integers to doubles
fH = (double)bH * BYTE_TO_double;
fS = (double)bS * BYTE_TO_double;
fV = (double)bV * BYTE_TO_double;
// Convert from HSV to RGB, using double ranges 0.0 to 1.0
int iI;
double fI, fF, p, q, t;
if( bS == 0 ) {
// achromatic (grey)
fR = fG = fB = fV;
}
else {
// If Hue == 1.0, then wrap it around the circle to 0.0
if (fH>= 1.0f)
fH = 0.0f;
fH *= 6.0; // sector 0 to 5
fI = floor( fH ); // integer part of h (0,1,2,3,4,5 or 6)
iI = (int) fH; // " " " "
fF = fH - fI; // factorial part of h (0 to 1)
p = fV * ( 1.0f - fS );
q = fV * ( 1.0f - fS * fF );
t = fV * ( 1.0f - fS * ( 1.0f - fF ) );
switch( iI ) {
case 0:
fR = fV;
fG = t;
fB = p;
break;
case 1:
fR = q;
fG = fV;
fB = p;
break;
case 2:
fR = p;
fG = fV;
fB = t;
break;
case 3:
fR = p;
fG = q;
fB = fV;
break;
case 4:
fR = t;
fG = p;
fB = fV;
break;
default: // case 5 (or 6):
fR = fV;
fG = p;
fB = q;
break;
}
}
// Convert from doubles to 8-bit integers
int bR = (int)(fR * double_TO_BYTE);
int bG = (int)(fG * double_TO_BYTE);
int bB = (int)(fB * double_TO_BYTE);
// Clip the values to make sure it fits within the 8bits.
if (bR > 255)
bR = 255;
if (bR < 0)
bR = 0;
if (bG >255)
bG = 255;
if (bG < 0)
bG = 0;
if (bB > 255)
bB = 255;
if (bB < 0)
bB = 0;
// Set the RGB cvScalar with G B R, you can use this values as you want too..
return cv::Scalar(bB,bG,bR); // R component
}
int main(int argc,char** argv )
{
Mat im = imread("c:/data/football.png",0);
std::vector<std::vector<cv::Point> > contours;
std::vector<cv::Vec4i> hierarchy;
findContours(im.clone(), contours, hierarchy, CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE);
vector<Rect> boxes;
for(size_t i = 0; i < contours.size(); i++)
{
Rect r = boundingRect(contours[i]);
boxes.push_back(r);
}
DbScan dbscan(boxes,20,2);
dbscan.run();
//done, perform display
Mat grouped = Mat::zeros(im.size(),CV_8UC3);
vector<Scalar> colors;
RNG rng(3);
for(int i=0;i<=dbscan.C;i++)
{
colors.push_back(HSVtoRGBcvScalar(rng(255),255,255));
}
for(int i=0;i<dbscan.data.size();i++)
{
Scalar color;
if(dbscan.labels[i]==-1)
{
color=Scalar(128,128,128);
}else
{
int label=dbscan.labels[i];
color=colors[label];
}
putText(grouped,to_string(dbscan.labels[i]),dbscan.data[i].tl(), FONT_HERSHEY_COMPLEX,.5,color,1);
drawContours(grouped,contours,i,color,-1);
}
imshow("grouped",grouped);
imwrite("c:/data/grouped.jpg",grouped);
waitKey(0);
}
这篇关于在OpenCV中的聚类图像片段的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！