采样Sampling

采样是把连续的光切成数字的动作——数字影像的本质就是「用有限个数字近似连续的光」。

• 四个方向各切一次：空间切成网格（像素）、时间切成瞬间（帧）、幅度切成台阶（位深）、颜色约定坐标系（色域 + 传递函数）。
• 采样的代价：格子外的信息永久丢失；噪点、色带不是软件的锅，是近似的代价（见 像素、帧、色深 · 色彩精度）。
• 为什么值得懂它：分辨率、帧率、位深、色域的每一次取舍，都是在决定「哪里切、切多细」。

Sampling is the act of cutting continuous light into numbers — the nature of digital images is "approximating continuous light with finitely many numbers".

• Four cuts in four directions: space into a grid (pixels), time into instants (frames), amplitude into steps (bit depth), colour by agreed coordinates (gamut + transfer function).
• The cost of sampling: what falls outside the grid is gone for good; noise and banding are not the software's fault — they are the price of approximation (see Pixel, Frame, Bit depth · Colour precision).
• Why it matters: every trade among resolution, frame rate, bit depth and gamut is deciding "where to cut, and how fine".