1 NIR and SWIR cameras mostly detect scattered object radiation and need external irradiation provided by the Sunshine. Many observed objects have temperatures below a hundred°C (212°F). Their respective object radiation is just too weak to become detected by NIR and SWIR sensors, but MWIR and LWIR cameras quickly detect https://thermalimaging85062.collectblogs.com/73304058/what-does-infrared-imaging-mean