Visible and Near-Infrared Imaging Instrument is one of the most important instrument for remote sensing. In this paper I tried to give a fundamental explanation of the instrument. So this paper consists of following parts : 1) Introduction. 2) Operational principles and mechanisms of imaging instruments : in this part the principles of mechanical scanner and electronic scanner are explained, then typical examples of these scanner are presented. There are included also the Stereosat system and Space Telescope (CCD Planetary Camera), but not included the MOS-1 MESSR and VTIR because some of the design parameters are not disclosed yet. 3) Some considerations of scanning mechanism : in this part comparison of object plane scan and image plane scan, considerations on limitation of mechanical scanning and uniformity of filter response of LANDSAT MSS, OTF of wide angle catadioptoric telescope for electronic scanner with CCD and characteristics of CCD linear array are given. 4) Onboad calibration : in this part a method of relative radiometric calibration is given, then shown some examples of onboad calibration systems including LANDSAT MSS, TM, SPOT HRV and Skylab S -192 MSS systems. The luna surface reflectance chacteristics are also presented as a candidate reference. 5) Future remote sensing system and sensor : in this part some forecasts for earth observation system and sensor in 1990s are given. Coneepts of reconfiguration in orbit, multipurpose earth observation system and smart sensor are stressed as the most important key technologies.

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Two RBV (Return Beam Vidicon) cameras onboard Landsat - 3 have variability of sensitivity in the spatial location on the face of vidicon. This phenomenon in defined as shading by NASA and has been great concerns to all Landsat ground station operators in the world.
The characterisitics of the shading is obtained through the analysis of 3 years calibration lamp data which are output voltage of RBV cameras for illumination of calibration lamp at 80, 15 and 0% of the specified maximum intensity of illumination. The analysis indicates that large variability of offset began to appear in both cameras since February 1981. In addition in case of Camera - 1 a sharp drop in offset value occurred in July 1981. In general the sensitivity of Camera - 2 has been more stable than that of Camera - 1. It is also found that fairly complicated two dimensional shading pattern exists…too difficult to eliminate by a simple method.
Two shading correction methods have been developed, one to apply Mss data the other to apply masking and calibration lamp data. In the first method, the data of MSS Bands 4, 5 and 6 are used with Band - 4 and 5 data double weighted. Due to longer computer time, this method is not suitable for an operational use at the ground station. In the second method, a scene over the clear ocean is used for masking since a clear ocean surface gives a fairly uniform reflectance. In this method correction for variation of gain obtained from calibration lamp data is applied.
The image processed by the new methods shows a great improvement in image quality compared with that processed by the current method in which corrections are made blockwise depending on a calibration curve for each of 18×18 blocks of an RBV image.

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This article shows three procedures, calibration, pre-processing and atmosheric attenuation correction for the Geostationary Meteorological Satellite (GMS) image data, which have been used for operational purposes at the Meteorological Satellite Center (MSC). Those are essential to process the image data for extracting the meteorological information like those cloud wind vector, cloud topheight, etc. The VISSR (Visible and Infrared Spin Scan Radiometer) calibration programs ensure the infrared (IR) level counts-to-equivalent black body temperature conversion table and the visible (VIS) level counts-to-albedo conversion table, based on needed information obtained from the telemetry data. The pre-processing program has several functions of implantation of missing scan line, blocking and sampling, registration, etc. Results are stored on a disk file to realize a high-speed access for displaying the image data on TV-display. IR channel of VISSR observes radiances in 10.5-12. 5μm region of spectrum. In this region is attenuated by the atmosphere. The empirical correction program for atmosheric absorption has been developed using the climatological vertical temperature and dew point temperature profile data.

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In the numerical processing of multispectral remote sensing data, it has been well discussed that the atmospheric scattering gives rise to the blurring effect on target radiance profiles surrounded by relatively luminous background. Furthermore, it has also been argued that the removal of atmospheric effects from the observed data enables one to enhance the quality of the terrestrial imagery remotely sensed from space and air.
An aim of the present paper is firstly to elucidate how to determine the diffusely reflected and transmitted intensities of radiation by Earth-Atmosphere system, bounded by the horizontally nonuniform albedos of diffusely reflecting underlying surface. Our emphasis is put not only on the solution of direct problem, but also on that of the inverse problem. In other words, an allowance is made for the linear least-squares estimation of the optical parameters of Earth-Atmosphere system. Based on the atmospheric models similar to the Elterman model, the evaluation of total spectral radiance at top is performed with the aid of Atmospheric Effects Correction System (AECS). In this context, the analytical and numerical solutions of contrast transfer problems are discussed, allowing for several kinds of atmospheric models. Finally, the signature extension is dealt with the use of AECS and furthermore it is applied to LANDSAT MSS data.

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With rapid progress of scientific technology in recent time, researches of remote sensing are in developing period after passed its twilight age. At the present, development of system to use jointly as well as effectively both of airbone remote sensing and satellite has been recognized. The authors have been trying for few years to apply the remote sensing to limnological field. In this paper, some aspects of limnological character of Biwa lake as well as its surrounding are investigated through analysis and estimation of the remote sensing data obtained by the airborne and Landsat and then present a view of possibility to apply the remote sensing to the enbironmental research of extensive inland water region such as the lake. Content of this study is summarized as follows.
(1) Constructiod of regional data base for the purpose of using effectively the remote sensing data.
(2) Consideration of accuracy of current distribution measurement with the applicatiol of airborne triangular surveving.
(3) Discussion about the utilization of the airborne MSS data to the environmental survey in the lake.

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