Spectral filtering

Spectral filtering is most commonly used to either select or eliminate information from an image based on the wavelength of the information. This filtering is usually effected by passing the light through a glass or plastic window that has been specially treated to transmit or absorb/reflect some wavelengths.

1. What is frequency filtering?
2. What are the different types of filtering in computer?
3. What is filtering in sensors?
4. How do signal filters work?

What is frequency filtering?

Frequency Domain Filters are used for smoothing and sharpening of image by removal of high or low frequency components. Sometimes it is possible of removal of very high and very low frequency. Frequency domain filters are different from spatial domain filters as it basically focuses on the frequency of the images.

What are the different types of filtering in computer?

Filters can be active or passive, and the four main types of filters are low-pass, high-pass, band-pass, and notch/band-reject (though there are also all-pass filters).

What is filtering in sensors?

The filtering effects in a sensor model may include explicit filters, such as when electrical components are used to attenuate noise. The filtering effects can also be implicit in the sensor structure such as when the thermal inertia of a temperature sensor produces phase lag in sensor output.

How do signal filters work?

When the signal frequency is within the filter's pass band, the filter passes the signal. As the signal moves out of the pass band, the filter begins to attenuate the signal. Note that the transition from the pass band to the stop band is a gradual process, where the filter's response decreases continuously.