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#include "tophatconvolution.h"
#include <schaapcommon/math/convolution.h>
using aocommon::Image;
namespace wsclean::tophat_convolution {
Image MakeTopHatImage(size_t width, size_t height, double tophat_radius) {
const ssize_t radius_squared =
static_cast<size_t>(tophat_radius * tophat_radius);
const ssize_t x_mid = (width - 1) / 2;
const ssize_t y_mid = (height - 1) / 2;
Image result(width, height, 0.0);
size_t sum = 0;
for (ssize_t y = 0; y != static_cast<ssize_t>(height); ++y) {
float* result_row = &result[y * width];
const ssize_t dy = y - y_mid;
for (ssize_t x = 0; x != static_cast<ssize_t>(width); ++x) {
const ssize_t dx = x - x_mid;
if (dx * dx + dy * dy <= radius_squared) {
result_row[x] = 1.0;
++sum;
}
}
}
result *= 1.0f / sum;
return result;
}
void Convolve(Image& input, double radius) {
size_t kernel_size = static_cast<size_t>(std::floor(radius)) * 2 + 1;
if (kernel_size % 2 == 0) ++kernel_size;
const Image kernel = MakeTopHatImage(kernel_size, kernel_size, radius);
schaapcommon::math::ResizeAndConvolve(
input.Data(), input.Width(), input.Height(), kernel.Data(), kernel_size);
}
} // namespace wsclean::tophat_convolution
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