gaussian_blur() [1/2]

MAYAFLUX_API void MayaFlux::Kinesis::Vision::gaussian_blur	(	std::span< const float >	src,
		std::span< float >	tmp,
		std::span< float >	dst,
		uint32_t	w,
		uint32_t	h,
		float	sigma
	)

Gaussian blur writing into caller-supplied buffers.

Parameters

src	Input span, size w * h.
tmp	Scratch span for horizontal pass, size >= w * h.
dst	Output span, size >= w * h.
w	Image width in pixels.
h	Image height in pixels.
sigma	Standard deviation in pixels. Must be > 0.

Definition at line 522 of file ImageFilter.cpp.

{
    const auto radius = static_cast<int32_t>(std::ceil(3.0F * sigma));
    const int32_t size = 2 * radius + 1;
 
    std::vector<float> kernel(static_cast<size_t>(size));
    float sum = 0.0F;
 
    const float inv_2s2 = 1.0F / (2.0F * sigma * sigma);
    for (int32_t i = -radius; i <= radius; ++i) {
        const float v = std::exp(-static_cast<float>(i * i) * inv_2s2);
        kernel[static_cast<size_t>(i + radius)] = v;
        sum += v;
    }
 
    auto kmap = Eigen::Map<Eigen::ArrayXf>(kernel.data(), static_cast<Eigen::Index>(kernel.size()));
    kmap /= sum;
    filter_separable(src, tmp, dst, w, h, kernel, kernel);
}

References filter_separable(), h, radius, and sigma.

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