Calibrating the elements of a multispectral imaging system

We describe a method to calibrate the elements of a multispectral system aimed at skylight imaging, which consists of a monochrome charge-coupled device (CCD) camera and a liquid-crystal tunable filter (LCTF). We demonstrate how to calibrate these two devices in order to build a multispectral camera that can obtain spectroradiometric measurements of skylight. Spectral characterizations of the tunable filter and the camera are presented together with a complete study into correcting temporal and spatial noise, which is of key importance in CCDs. We describe all the necessary steps to undertake this work and all the additional instrumentation that must be used to calibrate the radiometric devices correctly. We show how this complete study of our multispectral system allows us to use it as an accurate, high resolution spectroradiometer.This work was financed by the Spanish Red Temática “CIENCIA Y TECNOLOGÍA DEL COLOR” (FIS2005-25312-E), the Spanish Ministry of Education and Science, and the European Fund for Regional Development (FEDER) through grant FIS2007-60736. We thank our English colleague A. L. Tate for revising our English text.Peer reviewe

Application of LANDSAT to the surveillance of lake eutrophication in the Great Lakes basin

The author has identified the following significant results. A step-by-step procedure for establishing and monitoring the trophic status of inland lakes with the use of LANDSAT data, surface sampling, laboratory analysis, and aerial observations were demonstrated. The biomass was related to chlorophyll-a concentrations, water clarity, and trophic state. A procedure was developed for using surface sampling, LANDSAT data, and linear regression equations to produce a color-coded image of large lakes showing the distribution and concentrations of water quality parameters, causing eutrophication as well as parameters which indicate its effects. Cover categories readily derived from LANDSAT were those for which loading rates were available and were known to have major effects on the quality and quantity of runoff and lake eutrophication. Urban, barren land, cropland, grassland, forest, wetlands, and water were included

Remote sensing research studies

There are no author-identified significant results in this report

An integrated study of earth resources in the State of California using remote sensing techniques

The author has identified the following significant results. The supply, demand, and impact relationships of California's water resources as exemplified by the Feather River project and other aspects of the California Water Plan are discussed

Multispectral Resource Sampler Workshop

The utility of the multispectral resource sampler (MRS) was examined by users in the following disciplines: agriculture, atmospheric studies, engineering, forestry, geology, hydrology/oceanography, land use, and rangelands/soils. Modifications to the sensor design were recommended and the desired types of products and number of scenes required per month were indicated. The history, design, capabilities, and limitations of the MRS are discussed as well as the multilinear spectral array technology which it uses. Designed for small area inventory, the MRS can provide increased temporal, spectral, and spatial resolution, facilitate polarization measurement and atmospheric correction, and test onboard data compression techniques. The advantages of using it along with the thematic mapper are considered

Summaries of the Third Annual JPL Airborne Geoscience Workshop. Volume 1: AVIRIS Workshop

This publication contains the preliminary agenda and summaries for the Third Annual JPL Airborne Geoscience Workshop, held at the Jet Propulsion Laboratory, Pasadena, California, on 1-5 June 1992. This main workshop is divided into three smaller workshops as follows: (1) the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) workshop, on June 1 and 2; (2) the Thermal Infrared Multispectral Scanner (TIMS) workshop, on June 3; and (3) the Airborne Synthetic Aperture Radar (AIRSAR) workshop, on June 4 and 5. The summaries are contained in Volumes 1, 2, and 3, respectively

Museum Lighting - an holistic approach

Among the environmental parameters that effect exhibited artifacts, light is the most complex and the only essential for the observer as to appreciate the artifacts, thus being one of the most critical variables of art exposure. Research on strategies for energy saving and the renovation of light destined to Heritage is examined by daylight admission and Light-Emitting Diode (LED) technology. The extended review of the literature presented below, over museum lighting, evidenced the parallel advance of lighting principles with lighting design, concerning what determines visual quality and perception. Lighting quality is an interdisciplinaryfield of research affecting human activity and under a requested task, visual performance, while at the same time improving well-being. In this sense, the role of the lighting designer is to match and rank human needs with economic and environmental aspects as to architectural principles and to translate the results into a feasible design and an efficient installation. Quality factors for art exposure, involving color fidelity and damage, along with visual perception necessitate of useful metrics through established criteria. The challenge for the museum for a holistic design of natural and artificial light is still missing of substantial metrics, even though recent findings provide some insight on the workflow to establish. Luminance-based design metrics and contrast criteria are used in this study as key strategies for museum lighting, combining comfort and viewing fine arts through advanced computer rendering. The exploration of the transition inside a daylit gallery where moving in the museum environment offers an experience for a series of adaptation changes through photopic, mesopic and dark-adapted scotopic function, along with change on the sensitivity of the spectrum. The luminance appearance and the transition adaptation in the museum field lack of research examination; the relationship of prescriptive requirements and luminance- based design has been explored initially in the field of road lighting, where the relative visual performance has been evidenced to be in the center of the CIE standard for tunnel lighting. Daylight simulation via climate-based modeling, introducing daylight filters as solar shading devices, has been proposed as the object of experimental research, connecting light “filtering” with luminance; this workflow could be applied in several fields of research considering museum environment and give responses in the preservation of artwork involving daylight. The subject of this thesis is the proposal of a ‘trama’ surface installed on windows to reduce and control daylight, studying how energy and conservation targets can be achieved. New light sources and smart control systems will integrate to a holistic approach for museum lighting design

Synthetic simulation and modeling of image intensified CCDs (IICCD)

Image intensifying cameras have been found to be extremely useful in low-light-level (LLL) scenarios including military night-vision and civilian rescue operations. These sensors utilize the available visible region photons and an amplification process to produce high-contrast imagery. Today\u27s image intensifiers are usually attached to a CCD and incorporate a microchannel plate (MCP) for amplification purposes. These devices are commonly referred to as image intensified CCDs (IICCD). To date, there has not been much work in the area of still-frame, low-light-level simulations with radiometric accuracy in mind. Most work has been geared toward real-time simulations where the emphasis is on situational awareness. This research proposes that a high fidelity simulation environment capable of producing radiometrically correct multi-band imagery for low-light-level conditions can be an extremely useful tool for sensor design engineers and image analysts. The Digital Imaging and Remote Sensing (DIRS) laboratory\u27s Image Generation (DIRSIG) model has evolved to respond to such modeling requirements. The presented work demonstrates a low-light-level simulation environment (DIRSIG) which incorporates man-made secondary sources and exoatmospheric sources such as the moon and starlight. Similarly, a user-defined IICCD camera model has been developed that takes into account parameters such as MTF and noise

Emission and reflection from healthy and stressed natural targets with computer analysis of spectroradiometric and multispectral scanner data

Special emphasis was on corn plants, and the healthy targets were differentiated from stressed ones by remote sensing. Infrared radiometry of plants is reviewed thoroughly with emphasis on agricultural crops. Theory and error analysis of the determination of emittance of a natural target by radiometer is discussed. Experiments were conducted on corn (Zea mays L.) plants with long wavelength spectroradiometer under field conditions. Analysis of multispectral scanner data of ten selected flightlines of Corn Blight Watch Experiment of 1972 indicated: (1) There was no regular pattern of the mean response of the higher level/levels blighted corn vs. lower level/levels blighted corn in any of the spectral channels. (2) The greater the difference between the blight levels, the more statistically separable they usually were in subsets of one, two, three and four spectral channels