IM201 - Introduction to image processing

The perception of an image’s content changes little when an increasing function is applied to it. However, if the function is non-increasing, then the perception of the content changes completely. We are sensible to local rather than global changes of contrast. From now on, we are denoting $u \colon \Omega \to \mathbb{R}$ our image, where $\vert \Omega \vert = M \times N$ is a discrete rectangular grid. Also, we are assuming that $u$ takes discrete values $y_0 < \dots < y_{n - 1}$ (usually $0$ to $255$). ...

The pinhole model The first very simple way to acquire images is with the pinhole model. Here, part of the light coming from the object passes through a small aperture $O$ and is projected onto the focal plane. We do this so that each point of the object is represented by a ray. Otherwise, the image would not be formed. The distance $f$ is called the focal length. Let’s suppose we have the following model to describe the pinhole: ...