角点：最直观的印象就是在水平、竖直两个方向上变化均较大的点，即Ix、Iy都较大

边缘：仅在水平、或者仅在竖直方向有较大的变化量，即Ix和Iy只有其一较大

平坦地区：在水平、竖直方向的变化量均较小，即Ix、Iy都较小

-Corner: The most intuitive impression that the level of vertical change in both directions on both the larger point, that is, Ix, Iy are larger

Edge: only in the horizontal or vertical direction only in a greater change, that is, Ix and Iy, only one of the larger

Flat areas: the level of vertical changes in direction in both the smaller, that is, Ix, Iy are smaller