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       Hyperspectral Imaging Systems

 

The Bowling Green Geophysical Imaging Experiment (G-301) is the combined effort of Bowling Green State University (BGSU) and Hudson Research Inc. The purpose of the experiment is to perform geophysical remote sensing experiments aimed at passive measurement of specific chemical species with 15 narrow spectral bands and one broad spectral band that covers the full wavelength range of the instrument of 0.55 - 25 microns. The experiment will utilize an proprietary uncooled broadband infra-red/visible sensor and a camera and optical system controlled by an artificial intelligence program with an embedded Global Positioning System (GPS) capability. This project has been developed by Hudson Research as a practical demonstration of low cost high-resolution Hyper-Spectral Imaging. There are four scientific objectives in this project. Three are remote sensing experiments that utilize the unique characteristics of the Hyperspectral Imager to extract data about geological processes, earthquake activity, mineralogy, etc.. The fourth experiment is a test of a novel approach to resolving the problem of Single Event Upset (SEU) which besets almost all non-radiation hardened electronics when used in space. This technique has been developed exclusively by Hudson Research Inc. and if successful will be marketed to all manufacturers and users of electronics for space applications.

Spectral Range:           0.5 microns - 25 microns Spectral Resolution:
                                          adjustable 32 - 150 nm
Number of Bands:     16 Filter Wheel Only; Continuous with Fabry-Perot
Spectral Sensitivity:  Shot-Noise Limited
Dynamic Range:        >50,000:1
System Gain:               >1018; digitally programmable
Video Resolution:     640 x 480 x 10 digital format
Video Acquisition:    32 Frame Burst @ 10 Second Intervals for 5 minutes
Ground resolution:  10KM - 100KM
Pixel size:                    20 M/pixel - 200M/pixel

The imaging sensor is based on a Quantum Ferroelectric (QFE) photocathode integrated with a high resolution ruggedized vidicon type electron tube. The QFE sensor is notable because it has nearly flat response from 0.55 microns (green) and 25 microns in the far infra-red. For the GAS program, in order to simplify data recording, the system will be limited to 640 x 480 x 10 standard digital format per frame for simplicity in interface with the digital computer hardware.

Hudson Research Inc is proud to present the first Sub-BLIP image to be released to the public. This image is presented with an accompanying visible light view showing the experimental setup. There is a freezer pack (blue object, 28 F) with a plastic cap (36 F) and a small white plastic button (40 F) in its center, a bag of ice cubes (32 F), a cigarette (coal = 1800 F) and a "tensor" lamp (tungsten filament 5300 K; filtered by glass envelope). Room temperature is 69.3 F as displayed on the digital multimeter in the frame. The infra-red view shows all of these objects, and a hand (98.6 F) in the same frame. This represents an interscene dynamic range of over 5000K!

  Experimental Setup

To See a Temperature Map of this experiment, Click Here

  Sub-Blip Image

Device Description: The G-301 experiment consists of a high resolution return beam video camera equipped with a QFE detector, tunable filter and reflective Cassegrain zoom lens. This forms the central core of the experiment. The balance of the equipment consists of a 486 computer, fitted with a frame grabber, embedded GPS receiver, image processor, secondary data acquisition system, single event upset detector. Large hard disks will store the data and program information. The system will be activated by the astronauts when time allows and will then perform its acquisition sequence automatically. Figure 1 depicts the conceptual structure of G-301.

 

Figure 1 G-301: Internal Structure

Major Sub-Systems

(1) Lens: The lens will be a modified Cassegrain (reflective) zoom system with an anticipated effective focal length of 200 - 2000 mm. It will have an entrance aperture of 4.5 inches (f4 - f16) and will be of athermal open web construction.

(2) Filter: The filter will be a combination of a filter wheel and a continuously tunable Fabry-Perot. The filter will have up to 4096 bands that are adjustable from 32 to 150 nanometers in bandwidth. The filter will be actuated by a piezoelectric positioner, which in turn will be driven by the system controller which will have a dedicated output port .

(3) QFE Camera: The QFE camera will be mounted in a tube parallel to the telescope tube. The camera high voltage circuitry will be potted in a non-outgassing material to protect it from the vacuum environment and vibration as well as minimizing contamination due to outgassing. The filament of the QFE tube will also serve as the heater for the camera package.

(4) Support Electronics: There will be an on-board 486 microcomputer that will operate and monitor the functions of the experiment. It is equipped with a video frame grabber, a data acquisition and interface, and hard disk drives for data storage. It will also contain an embedded GPS receiver which is part of an autonomous navigation system that controls targeting. It will serve as the command interpreter for data from the NASA interface. A single board image processor with frame grabber will integrated with the host computer. This will digitize the output from the QFE detector and transfer it to the system. A data acquisition and interface board provides digital inputs from the NASA interface, digital outputs for filter control, control signal for the zoom mechanism. It also monitors the Single Event Upset experiment and takes temperature data from a number of points in the system for radiometric calibration purposes. It also provides control signals for the camera controller. There is no keyboard or display and the system will only be operated in either the totally autonomous mode, the slave mode under the control of the Payload Controller, or the ground support computer. CONTACT US for further Information . 

     
                     
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