Visible And Near Infrared Radiometer Research Articles

Operational algorithm to correct the along track and across track striping in the JERS-1 OPS images

Abstract As a result of unpredictable power supply problems, the images of the Visible and Near Infrared Radiometer (VNIR) of the Optical Sensor (OPS) onboard the ‘Fuyo-1’ Japan's Earth Resource Satellite (JERS-1), do present along track and across track striping. This striping has been characterized both in frequency and intensity. A fast statistical method has been implemented to remove the noise introduced by the system. This correction does not alter the radiometric properties of the image. The correction has been validated over a representative set of images and adopted in the operational JERS-1 OPS processing chain of ESA (European Space Agency) installed at Fucino and Kiruna.

Radiometric Calibration of the EOS ASTER Instrument

Pre-flight and in-flight radiometric calibration plans are described for a multispectral optical imager of high spatial resolution for remote sensing of land surfaces and clouds from orbit, which will be launched in 1998 on NASA's EOS-AM1 spacecraft. The instrument named ASTER consists of three radiometers for three separate spectral regions, the visible and near-infrared radiometer (VNIR), the shortwave infrared radiometer (SWIR), and the thermal infrared radiometer (TIR). Absolute radiometric accuracy to better than 4% is required for the VNIR and SWIR radiance measurements, and from 1 K to 3 K, depending on the temperature region, from 200 K to 370 K for the TIR temperature measurements. The basic approach to in-flight calibration is to introduce a reference beam at the front end of the radiometer to calibrate the whole system in orbit. Thus the ASTER instrument is installed with internal on-board calibration units which include, as reference sources, incandescent lamps for the VNIR and SWIR and a black-body radiator for the TIR. Calibration reliability of the VNIR and SWIR is enhanced by a dual system of on-board calibration units and high stability halogen lamps. A ground calibration system of spectral radiances traceable to fixed-point black bodies is used for the pre-flight VNIR and SWIR calibrations.

Preliminary design concept and development targets of Japanese optical sensor for Eos-A

Abstract The Japanese optical sensor for Eos-A platform is an advanced multispectral imager with a high spatial, spectral and radiometric resolutions, and tentatively named ITIR. The ITIR consists of three subsystems: a visible and near infrared radiometer(VNIR), a short wave infrared radiometer(SWIR), and a thermal infrared radiometer(TIR). Further, the VNIR has two telescopes necessary to realize the stereoscopic viewing capability. Significant design challenges are realization of the pushbroom type VNIR sensor with a high spatial resolution of 15 m, the pushbroom type SWIR sensor with a high spectral resolution and the whiskbroom type TIR sensor with high spatial, spectral and radiometric resolutions. Long life mechanical cooler for the SWIR and the TIR sensors are also a component with a technical risk.