uchar interpolate_bilinear(cv::Mat& mat_src, double ri, int rf, int rc, double ti, int tf, int tc)
{
double inter_value = 0.0;
if (rf == rc && tc == tf)
{
inter_value = mat_src.ptr<uchar>(rc)[tc];
}
else if (rf == rc)
{
inter_value = (ti - tf) * mat_src.ptr<uchar>(rf)[tc] + (tc - ti) * mat_src.ptr<uchar>(rf)[tf];
}
else if (tf == tc)
{
inter_value = (ri - rf) * mat_src.ptr<uchar>(rc)[tf] + (rc - ri) * mat_src.ptr<uchar>(rf)[tf];
}
else
{
double inter_r1 = (ti - tf) * mat_src.ptr<uchar>(rf)[tc] + (tc - ti) * mat_src.ptr<uchar>(rf)[tf];
double inter_r2 = (ti - tf) * mat_src.ptr<uchar>(rc)[tc] + (tc - ti) * mat_src.ptr<uchar>(rc)[tf];
inter_value = (ri - rf) * inter_r2 + (rc - ri) * inter_r1;
}
return (uchar)inter_value;
}
bool cartesian_to_polar(cv::Mat& mat_c, cv::Mat& mat_p, int img_d)
{
int color_num = mat_c.channels();
cout << "color_num=" << color_num << endl;
mat_p = cv::Mat::zeros(img_d, img_d, CV_8UC1);
//mat_p = cv::Mat::zeros(img_d, img_d, CV_8UC3);
//mat_p = cv::Mat::zeros(img_d, img_d, color_num);
int line_len = mat_c.rows;
int line_num = mat_c.cols;
double delta_r = (2.0*line_len) / (img_d - 1); //半径因子
double delta_t = 2.0 * PI / line_num; //角度因子
double center_x = (img_d - 1) / 2.0;
double center_y = (img_d - 1) / 2.0;
for (int i = 0; i < img_d; i++)
{
for (int j = 0; j < img_d; j++)
{
double rx = j - center_x; //图像坐标转世界坐标
double ry = center_y - i; //图像坐标转世界坐标
double r = std::sqrt(rx*rx + ry*ry);
if (r <= (img_d - 1) / 2.0)
{
double ri = r * delta_r;
int rf = (int)std::floor(ri);
int rc = (int)std::ceil(ri);
if (rf < 0)
{
rf = 0;
}
if (rc >(line_len - 1))
{
rc = line_len - 1;
}
double t = std::atan2(ry, rx);
if (t < 0)
{
t = t + 2.0 * PI;
}
double ti = t / delta_t;
int tf = (int)std::floor(ti);
int tc = (int)std::ceil(ti);
if (tf < 0)
{
tf = 0;
}
if (tc >(line_num - 1))
{
tc = line_num - 1;
}
mat_p.ptr<uchar>(i)[j] = interpolate_bilinear(mat_c, ri, rf, rc, ti, tf, tc);
/*
mat_p.ptr<Vec3b>(i, j)[0] = interpolate_bilinear(mat_c, ri, rf, rc, ti, tf, tc);
mat_p.ptr<Vec3b>(i, j)[1] = interpolate_bilinear(mat_c, ri, rf, rc, ti, tf, tc);
mat_p.ptr<Vec3b>(i, j)[2] = interpolate_bilinear(mat_c, ri, rf, rc, ti, tf, tc);
*/
}
}
}
return true;
}