Set of 4 Fourier filters

Principle :
- Fourier filtering makes it possible to modify certain undesirable frequencies of an object by inserting a suitable mask in the Fourier plane (or focal plane of the initial image).
- Thus, the image (or the different spatial frequencies that constitute it), is interpreted as a diffraction figure.

These measurements therefore require a collimated, but above all purified light source: this is why the Ovio Laser Torch (ref. 204 080), ready to use and pre-adjusted, is ideal for this type of technique.

Results :
- Double contrast (203 248): Influence of the opening of the slit (reading on the micrometer screw) on the jamming of spaced lines of different frequencies
- Mixed letter F and O filter (203 254): Shape recognition: the letter F or the letter O can be highlighted depending on the direction of the opening of the filter slot.
- Descreening filter (203 256): Influence of the opening of the slit (reading on the micrometric screw) on the interference of spaced lines of different frequencies
- Multiple grid filter (203 251): presents lines of variable thickness which makes it possible to further emphasize certain details (high-pass and low-pass filtering with circles and rectangles) as well as to observe the influence of the width of the slit on the produced image.