Project Mercury was America's attempt to place a man in orbit around the Earth. Jim Lovell was one of the 110 test pilots considered for selection but a temporary liver condition put paid to his chances.
Core recommender toggle，这一点在同城约会中也有详细论述
You look at a region of the image. If all the pixels are roughly the same color (below some threshold), you store the average color for the whole region as a single value. If the pixels vary too much, you split the region into four quadrants and try again.，更多细节参见91视频
Gerd Baumgarten