void interp_extremum(int octv, int intvl, int r, int c)
{
double xi = 0, xr = 0, xc = 0;
int step = init_sample * COpenSURF.cvRound(COpenSURF.pow(2.0f, octv));
// Get the offsets to the actual location of the extremum
bool bok = interp_step(octv, intvl, r, c, out xi, out xr, out xc);
if (bok == false)
{
return;
}
// If point is sufficiently close to the actual extremum
if (COpenSURF.fabs((float)xi) <= 0.5 && COpenSURF.fabs((float)xr) <= 0.5 && COpenSURF.fabs((float)xc) <= 0.5)
{
// Create Ipoint and push onto Ipoints vector
Ipoint ipt = new Ipoint();
ipt.x = (float)(c + step * xc);
ipt.y = (float)(r + step * xr);
ipt.scale = (float)((1.2f / 9.0f) * (3 * (COpenSURF.pow(2.0f, octv + 1) * (intvl + xi + 1) + 1)));
ipt.laplacian = (int)getLaplacian(octv, intvl, c, r);
ipts.Add(ipt);
}
}
void getUprightDescriptor()
{
int y, x, count = 0;
int scale;
float dx, dy, mdx, mdy;
float gauss, rx, ry, len = 0.0f;
float[] desc;
Ipoint ipt = ipts[index];
scale = (int)ipt.scale;
y = COpenSURF.cvRound(ipt.y);
x = COpenSURF.cvRound(ipt.x);
desc = ipt.descriptor;
// Calculate descriptor for this interest point
for (int i = -10; i < 10; i += 5)
{
for (int j = -10; j < 10; j += 5)
{
dx = dy = mdx = mdy = 0;
for (int k = i; k < i + 5; ++k)
{
for (int l = j; l < j + 5; ++l)
{
// get Gaussian weighted x and y responses
gauss = COpenSURF.gaussian(k * scale, l * scale, 3.3f * scale);
rx = gauss * haarX(k * scale + y, l * scale + x, 2 * scale);
ry = gauss * haarY(k * scale + y, l * scale + x, 2 * scale);
dx += rx;
dy += ry;
mdx += COpenSURF.fabs(rx);
mdy += COpenSURF.fabs(ry);
}
}
// add the values to the descriptor vector
desc[count++] = dx;
desc[count++] = dy;
desc[count++] = mdx;
desc[count++] = mdy;
// store the current length^2 of the vector
len += dx * dx + dy * dy + mdx * mdx + mdy * mdy;
}
}
// convert to unit vector
len = (float)Math.Sqrt(len);
for (int i = 0; i < 64; i++)
{
desc[i] /= len;
}
}
float getValLowe(int o, int i, int r, int c)
{
int index = (o * intervals + i) * (i_width * i_height) + (r * i_width + c);
if (m_det == null)
{
return(0);
}
if (index < 0 || index >= m_det.Length)
{
return(0);
}
return(COpenSURF.fabs(m_det[index]));
}
void getIpoint(int o, int i, int c, int r)
{
//! Interpolate feature to sub pixel accuracy
bool converged = false;
float[] x = new float[3];
for (int steps = 0; steps <= interp_steps; ++steps)
{
// perform a step of the interpolation
stepInterp(o, i, c, r, x);
// check stopping conditions
if (COpenSURF.fabs(x[0]) < 0.5 && COpenSURF.fabs(x[1]) < 0.5 && COpenSURF.fabs(x[2]) < 0.5)
{
converged = true;
break;
}
// find coords of different sample point
c += COpenSURF.cvRound(x[0]);
r += COpenSURF.cvRound(x[1]);
i += COpenSURF.cvRound(x[2]);
// check all param are within bounds
if (i < 1 || i >= intervals - 1 || c < 1 || r < 1 || c > i_width - 1 || r > i_height - 1)
{
return;
}
}
// if interpolation has not converged on a result
if (!converged)
{
return;
}
// create Ipoint and push onto Ipoints vector
Ipoint ipt = new Ipoint();
ipt.x = (float)(c + x[0]);
ipt.y = (float)(r + x[1]);
ipt.scale = (1.2f / 9.0f) * (3 * (COpenSURF.pow(2.0f, o + 1) * (i + x[2] + 1) + 1));
ipt.laplacian = (int)getLaplacian(o, i, c, r);
if (ipts == null)
{
ipts = new List <Ipoint>();
}
ipts.Add(ipt);
}
void getDescriptor()
{
int y, x, count = 0;
float dx, dy, mdx, mdy, co, si;
float[] desc;
int scale;
int sample_x;
int sample_y;
float gauss, rx, ry, rrx, rry, len = 0;
Ipoint ipt = ipts[index];
scale = (int)ipt.scale;
x = COpenSURF.cvRound(ipt.x);
y = COpenSURF.cvRound(ipt.y);
co = (float)Math.Cos(ipt.orientation);
si = (float)Math.Sin(ipt.orientation);
desc = ipt.descriptor;
// Calculate descriptor for this interest point
for (int i = -10; i < 10; i += 5)
{
for (int j = -10; j < 10; j += 5)
{
dx = dy = mdx = mdy = 0;
for (int k = i; k < i + 5; ++k)
{
for (int l = j; l < j + 5; ++l)
{
// Get coords of sample point on the rotated axis
sample_x = COpenSURF.cvRound(x + (-l * scale * si + k * scale * co));
sample_y = COpenSURF.cvRound(y + (l * scale * co + k * scale * si));
// Get the gaussian weighted x and y responses
gauss = COpenSURF.gaussian(k * scale, l * scale, 3.3f * scale);
rx = gauss * haarX(sample_y, sample_x, 2 * scale);
ry = gauss * haarY(sample_y, sample_x, 2 * scale);
// Get the gaussian weighted x and y responses on rotated axis
rrx = -rx * si + ry * co;
rry = rx * co + ry * si;
dx += rrx;
dy += rry;
mdx += COpenSURF.fabs(rrx);
mdy += COpenSURF.fabs(rry);
}
}
// add the values to the descriptor vector
desc[count++] = dx;
desc[count++] = dy;
desc[count++] = mdx;
desc[count++] = mdy;
// store the current length^2 of the vector
len += dx * dx + dy * dy + mdx * mdx + mdy * mdy;
} // for (int j = -10; j < 10; j+=5)
} // for (int i = -10; i < 10; i+=5)
// convert to unit vector
len = (float)Math.Sqrt(len);
for (int i = 0; i < 64; i++)
{
desc[i] /= len;
}
}
float getVal(int o, int i, int c, int r)
{
//! Return the value of the approximated determinant of hessian
return(COpenSURF.fabs(m_det[(o * intervals + i) * (i_width * i_height) + (r * i_width + c)]));
}