Multiple grid filter

Multiple Grid Filter.

Principle:

- Fourier filtering allows the modification of certain undesirable frequencies of an object by inserting a suitable mask in the Fourier plane (or the focal plane of the original image).

- Thus, the image (or the different spatial frequencies that constitute it) is interpreted as a diffraction pattern.

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

Results:

Slide 203 251 presents lines of variable thickness which allows for emphasizing certain details more (high-pass and low-pass filtering with circles and rectangles) as well as observing the influence of the slit width on the produced image.