我一直在尝试实现meanshift算法来跟踪物体,并研究了相关的概念。
目前为止,我已经成功地从我的相机生成了一个背投流,其中包含单通道色调ROI直方图和单通道色调视频流,这似乎还不错。我知道opencv库中有一个meanshift函数,但是我正在尝试使用opencv提供的数据结构自己实现一个函数,计算搜索窗口的矩并计算平均质心。但是由于某些原因,我无法找到代码中的问题,因为它始终会收敛到视频流的左上角,无论要跟踪的输入ROI(感兴趣区域)是什么。以下是计算搜索窗口质心的函数的代码片段,我认为问题出在这里,但不确定具体是什么问题。如果有人能指导我正确的方向,我将不胜感激:
void moment(Mat &backproj, Rect &win){
int x_c, y_c, x_c_new, y_c_new;
int idx_row, idx_col;
double m00 = 0.0 , m01 = 0.0 , m10 = 0.0 ;
double res = 1.0, TOL = 0.003 ;
//Set the center of search window as the center of the probabilistic image:
y_c = (int) backproj.rows / 2 ;
x_c = (int) backproj.cols / 2 ;
//Centroid search solver until residual below certain tolerance:
while (res > TOL){
win.width = (int) 80;
win.height = (int) 60;
//First array element at position (x,y) "lower left corner" of the search window:
win.x = (int) (x_c - win.width / 2) ;
win.y = (int) (y_c - win.height / 2);
//Modulo correction since modulo of negative integer is negative in C:
if (win.x < 0)
win.x = win.x % backproj.cols + backproj.cols ;
if (win.y < 0)
win.y = win.y % backproj.rows + backproj.rows ;
for (int i = 0; i < win.height; i++ ){
//Traverse along y-axis (height) i.e. rows ensuring wrap around top/bottom boundaries:
idx_row = (win.y + i) % (int)backproj.rows ;
for (int j = 0; j < win.width; j++ ){
//Traverse along x-axis (width) i.e. cols ensuring wrap around left/right boundaries:
idx_col = (win.x + j) % (int)backproj.cols ;
//Compute Moments:
m00 += (double) backproj.at<uchar>(idx_row, idx_col) ;
m10 += (double) backproj.at<uchar>(idx_row, idx_col) * i ;
m01 += (double) backproj.at<uchar>(idx_row, idx_col) * j ;
}
}
//Compute new centroid coordinates of the search window:
x_c_new = (int) ( m10 / m00 ) ;
y_c_new = (int) ( m01 / m00 );
//Compute the residual:
res = sqrt( pow((x_c_new - x_c), 2.0) + pow((y_c_new - y_c), 2.0) ) ;
//Set new search window centroid coordinates:
x_c = x_c_new;
y_c = y_c_new;
}
}
这是我在stackoverflow上的第二个查询,请原谅我可能忘记遵循的任何指南。
编辑
在WHILE-LOOP中将m00、m01、m10更改为块级变量,而不是函数级变量,感谢Daniel Strul指出,但问题仍然存在。现在搜索窗口会跳跃到框架边界,而不是聚焦于roi。
void moment(Mat &backproj, Rect &win){
int x_c, y_c, x_c_new, y_c_new;
int idx_row, idx_col;
double m00 , m01 , m10 ;
double res = 1.0, TOL = 0.003 ;
//Set the center of search window as the center of the probabilistic image:
y_c = (int) backproj.rows / 2 ;
x_c = (int) backproj.cols / 2 ;
//Centroid search solver until residual below certain tolerance:
while (res > TOL){
m00 = 0.0 , m01 = 0.0 , m10 = 0.0
win.width = (int) 80;
win.height = (int) 60;
//First array element at position (x,y) "lower left corner" of the search window:
win.x = (int) (x_c - win.width / 2) ;
win.y = (int) (y_c - win.height / 2);
//Modulo correction since modulo of negative integer is negative in C:
if (win.x < 0)
win.x = win.x % backproj.cols + backproj.cols ;
if (win.y < 0)
win.y = win.y % backproj.rows + backproj.rows ;
for (int i = 0; i < win.height; i++ ){
//Traverse along y-axis (height) i.e. rows ensuring wrap around top/bottom boundaries:
idx_row = (win.y + i) % (int)backproj.rows ;
for (int j = 0; j < win.width; j++ ){
//Traverse along x-axis (width) i.e. cols ensuring wrap around left/right boundaries:
idx_col = (win.x + j) % (int)backproj.cols ;
//Compute Moments:
m00 += (double) backproj.at<uchar>(idx_row, idx_col) ;
m10 += (double) backproj.at<uchar>(idx_row, idx_col) * i ;
m01 += (double) backproj.at<uchar>(idx_row, idx_col) * j ;
}
}
//Compute new centroid coordinates of the search window:
x_c_new = (int) ( m10 / m00 ) ;
y_c_new = (int) ( m01 / m00 );
//Compute the residual:
res = sqrt( pow((x_c_new - x_c), 2.0) + pow((y_c_new - y_c), 2.0) ) ;
//Set new search window centroid coordinates:
x_c = x_c_new;
y_c = y_c_new;
}
}
Mat
和Rect
的结构是什么?是否可以显示backproj
的小数据样本(大约10个点)以及win
的值?谢谢 - Daniel Strul