Subsampling is a digital imaging process in which a lower-resolution image is derived from a higher-resolution original using a mathematical algorithm. This technique reduces the number of pixels in an image, effectively compressing its size while attempting to preserve as much visual information as possible. Subsampling is commonly used in digital photography, video processing, and graphic design to create smaller file sizes for faster storage, transmission, or display without significantly degrading image quality.
The process can involve various algorithms, such as averaging neighboring pixels, selecting representative pixels, or applying filters, to maintain the overall appearance of the image. Subsampling is also widely employed in color image processing, where chroma subsampling reduces color resolution while maintaining luminance detail, optimizing images for formats like JPEG or video compression standards. By carefully balancing resolution reduction and visual fidelity, subsampling allows photographers, designers, and digital media professionals to manage large image datasets efficiently while maintaining an acceptable level of image quality.