Function Downscale

cpp/5_Domain_Specific/HSOpticalFlow/flowGold.cpp:131–149

////////////////////////////////////////////////////////////////////////// \brief resize image \param[in] src image to downscale \param[in] width image width \param[in] height image height \param[in] stride image stride \param[in] newWidth image new width \param[in] newHeight image new height \param[in] newStride image new stride \param[out] out downsc

/// \param[out] out         downscaled image data
///////////////////////////////////////////////////////////////////////////////
static void
Downscale(const float *src, int width, int height, int stride, int newWidth, int newHeight, int newStride, float *out)
{
    for (int i = 0; i < newHeight; ++i) {
        for (int j = 0; j < newWidth; ++j) {
            const int srcX = j * 2;
            const int srcY = i * 2;
            // average 4 neighbouring pixels
            float sum;
            sum = Tex2Di(src, width, height, stride, srcX + 0, srcY + 0);
            sum += Tex2Di(src, width, height, stride, srcX + 0, srcY + 1);
            sum += Tex2Di(src, width, height, stride, srcX + 1, srcY + 0);
            sum += Tex2Di(src, width, height, stride, srcX + 1, srcY + 1);
            // normalize
            sum *= 0.25f;
            out[j + i * newStride] = sum;
        }
    }
}

///////////////////////////////////////////////////////////////////////////////
/// \brief upscale one component of a displacement field