7. Sampling and Reconstruction
Radiance在胶平面上是连续函数，但是渲染的输出是离散的像素。
But what happens when we need the value of s signal at a location that we didn’t sample at? In such cases, we can use a process known as reconstruction to derive an approximation of the original continuous function. With this approximation we can then discretely sample its values at a new set of sample points, which is referred to as resampling. signal processing primer
7.1 Sampling Theory
the Fourier transform of a shah function with period T is another shah function with period 1/T. This reciprocal relationship between periods is important to keep in mind: it means that if the samples are farther apart in the spatial domain, they are closer together in the frequency domain.
- Antialiasing Techniques
NonUniform Sampling 以前是在整数倍周期位置采样，现在在整数倍附近$\frac{1}{2}$周期的位置随机选择一个采样点。 $\sum_{i=-\infty}^{\infty} \delta(x - (i + \frac{1}{2} - \xi)T)$