resamplen

Resamplen is a term that appears in discussions of resampling in digital signal processing and computer graphics. In general, resampling refers to changing the sampling rate or sampling grid of a signal or image, either to a higher rate (upsampling) or a lower rate (downsampling). Resamplen is often used as a neutral label for the operation itself, or as a project or library name in software contexts.

Methods to resample include interpolation-based approaches such as nearest neighbor, linear, and cubic interpolation, as well as filter-based methods that apply anti-aliasing and reconstruction kernels. In higher-accuracy settings, resampling can be performed with finite impulse response filters or with Fourier-domain techniques that implement sinc-like interpolation. In multi-dimensional data such as images or video, resampling is typically performed separately along each axis (separable filtering) or via more general three-dimensional kernels.

Quality considerations include the target sampling rate, the presence of aliasing in downsampling, and computational constraints. Downsampling usually requires pre-filtering to remove high-frequency content that cannot be represented at the lower rate. Upsampling requires interpolation to fill in intermediate samples. The choice of method affects artifacts such as blurring, ringing, or jagged edges.

Resampling is a common operation in audio processing, digital photography, video processing, and scientific data analysis. Software libraries commonly provide resampling functions, including in audio toolchains and image processing frameworks. Examples include libsamplerate for audio, OpenCV and Pillow for image data, and SciPy for scientific computing.

See also: resampling, interpolation, sampling theorem, polyphase filter, anti-aliasing.