Experiment Fourier filtering

Subjects discussed :
- High pass and low pass filtering
- Descreening
- Shape recognition
- Edge detection

Principles and objectives:
Filtering makes it possible to modify certain unwanted frequencies of an object by inserting a suitable mask in the Fourier plane. In this particular plane (focus plane of the initial image), the image or the different spatial frequencies which constitute it, are interpreted as a diffraction pattern.

These experiments require the use of a collimated but above all purified light source, which is why the laser torch is ideal for this technique.

Composition :
 ▪ 1 prismatic bench of 1 m with set of adjustable feet (ref.202519)
 ▪ 4 standard prismatic carriers (ref.202234)
 ▪ 1 prismatic carrier with vertical movement (ref.202237)
 ▪ 1 prismatic carrier with transverse and longitudinal movement (ref.202510)
 ▪ 1 laser torch (ref.204080)
 ▪ 1 adjustable slot with symmetrical orientable opening (ref.202424)
 ▪ 1 thin blade holder (ref.202448)
 ▪ 2 component holders with pins (ref.202442) and 1 Clix component holder (ref.204136)
 ▪ 1 set of 4 objects for Fourier filtering (double contrast grid, multiple grid, descreening, mixed letters)
 ▪ 2 micro-lithographed tokens for Fourier filtering (ref. 203260 and 203261)
 ▪ 2 lenses Ø40 mm (ref. 202273 and 202274)
 ▪ 1 white, squared metal screen 20x20 cm (ref.202368)
 ▪ 1 experiment note