High‑resolution (HR) optical imagers are passive, nadir‑viewing radiometers that measure reflected solar radiation in a limited set of broad spectral bands, using pushbroom or similar designs to build 2‑D images as the satellite moves along its orbit. Hyperspectral instruments, which sample a quasi‑continuous spectrum, are intentionally excluded from this category. Typical spatial resolutions for these systems range from about 10 m to 100 m.
