downsampled

Downsampled is the past participle form of downsample and is used as an adjective to describe data or signals that have been reduced in sampling rate or resolution. Downsampling is the process of creating a new data set at a lower sampling rate by selecting or aggregating samples from the original data. In digital signal processing, this is typically done by applying a low-pass filter to prevent aliasing, and then keeping every nth sample (decimation) or by more sophisticated resampling methods. The result is a downsampled signal with reduced bandwidth and data size.

In image and video processing, downsampling reduces spatial resolution. The original image or frame is resampled to a smaller grid using methods such as nearest neighbor, bilinear, or bicubic interpolation, or by averaging in blocks. The downsampled version occupies less storage and is faster to process, but preserves less detail and can introduce artifacts if high-frequency content is present.

In statistics and time-series analysis, downsampling refers to reducing the sampling frequency by selecting a subset of observations or by aggregating into larger time bins (e.g., taking mean values per minute from per-second data). The choice of method affects bias and variance and should reflect the analysis goals.

Applications include data compression, streaming, sensor networks, machine learning preprocessing, and visualization. Key considerations include avoiding aliasing, preserving representative features, and documenting the downsampling ratio and method used.