public OrientationAssignment(int fine_width, int fine_height, int num_octaves, int num_scales_per_octave,
int num_bins, double gaussian_expansion_factor, double support_region_expansion_factor,
int num_smoothing_iterations, double peak_threshold)
{
this.mNumScalesPerOctave = num_scales_per_octave;
this.mGaussianExpansionFactor = gaussian_expansion_factor;
this.mSupportRegionExpansionFactor = support_region_expansion_factor;
this.mNumSmoothingIterations = num_smoothing_iterations;
this.mPeakThreshold = peak_threshold;
this.mHistogram = new BilinearHistogram(num_bins);
// Allocate gradient images
this.mGradients = new GradientsImage_ARTK[num_octaves * this.mNumScalesPerOctave];
for (int i = 0; i < num_octaves; i++)
{
for (int j = 0; j < num_scales_per_octave; j++)
{
this.mGradients[i * num_scales_per_octave + j] = new GradientsImage_O1(fine_width >> i, fine_height >> i);
}
}
}
/**
* OrientationAssignment.computeの一部
* @param x
* @param y
* @param radius
* @param gw_scale
* @param i_histogram
*/
virtual public void buildOrientationHistogram(double x, double y, double radius, double gw_scale, BilinearHistogram i_histogram)
{
double[] a_buf = this._angle;
double[] m_buf = this._mag;
int xi = (int)(x + 0.5f);
int yi = (int)(y + 0.5f);
// Box around feature point
int x0 = xi - (int)(radius + 0.5f);
int x1 = xi + (int)(radius + 0.5f);
int y0 = yi - (int)(radius + 0.5f);
int y1 = yi + (int)(radius + 0.5f);
// Clip the box to be within the bounds of the image
int width_1 = this._size.w - 1;
int height_1 = this._size.h - 1;
if (x0 < 0)
{
x0 = 0;
} //x0 = math_utils.max2(0, x0);
if (x1 > width_1)
{
x1 = width_1;
} //x1 = math_utils.min2(x1, (int) g.getWidth() - 1);
if (y0 < 0)
{
y0 = 0;
} //y0 = math_utils.max2(0, y0);
if (y1 > height_1)
{
y1 = height_1;
} //y1 = math_utils.min2(y1, (int) g.getHeight() - 1);
double radius2 = Math.Ceiling(radius * radius);
// Build up the orientation histogram
for (int yp = y0; yp <= y1; yp++)
{
double dy = yp - y;
double dy2 = (dy * dy);
int y_ptr = this._size.w * yp;
for (int xp = x0; xp <= x1; xp++)
{
double dx = xp - x;
double r2 = (dx * dx) + dy2;
// Only use the gradients within the circular window
if (r2 > radius2)
{
continue;
}
int g2_ptr = y_ptr + xp; // const float* g = &y_ptr[xp<<1];
double angle = a_buf[g2_ptr]; // const float& angle = g[0];
double mag = m_buf[g2_ptr]; // const float& mag = g[1];
// Compute the gaussian weight based on distance from center of keypoint
double w = FastMath.fastexp6(r2 * gw_scale);
// Vote to the orientation histogram with a bilinear update
i_histogram.bilinearHistogramUpdate(angle, w * mag);
}
}
}
