An anti-aliasing filter is a device used in digital signal processing to prevent aliasing, which occurs when high-frequency signals are misrepresented as lower frequencies. By removing or reducing these high-frequency components before sampling, the filter ensures that the digital representation of the signal is accurate and maintains its quality. These filters are commonly used in various applications, including audio processing and image capture. In the context of digital cameras, anti-aliasing filters help to minimize moiré patterns and other artifacts that can arise from sampling images with fine details. This results in clearer and more accurate digital images.