Harris corner 角點偵測源代碼 source code

bool harris(const vector<float>& p,
    size_t w, size_t y, size_t x)
{
    // 閥值
    constexpr float r = 10;
    constexpr float thre = ((r + 1)*(r + 1)) / r;
    // 二維讀取
    auto at2d = [&](int y, int x) {return p[y*w + x];};
    // 公式
    float Dxx = 2 * at2d(y, x) - at2d(y, x-1) - at2d(y, x+1);
    float Dyy = 2 * at2d(y, x) - at2d(y-1, x) - at2d(y+1, x);
    float Dxy = at2d(y+1, x+1) + at2d(y-1, x-1)
        - at2d(y-1, x+1) - at2d(y+1, x-1);
    Dxy /= 4;
    float Tr = Dxx + Dyy;
    float Det = Dxx * Dyy - Dxy*Dxy;
    // 判斷閥值
    if ((Tr*Tr / Det) < thre) {
        return 1;
    } return 0; 
}

沒有針對邊緣防呆，記得避開邊緣的點

測試圖

​