The system and method allow spectroscopic analysis of vegetation or the like without effects from changing sun and cloud conditions, undesired portions of the area of interest or atmospheric disturbances. The system (1) includes a light source (5) such as a xenon flash lamp, a telescope (7), a spectrometer (9), an analog/digital converter (11), a memory (13), a display (15), and an on-board microprocessor (17) or a port (19) for attachment to a laptop computer. The system is taken to an area of interest in the woods (step 41), the vegetation is illuminated from below (step 43) and data are taken (step 45)

Kalshoven, James Edward

NASA Technical Reports Server

I11111 111ll Il1 Il11 III III III 11111 11111 11111 1ll11111 
US005914779A 
United States Patent [19] [ i l l  Patent Number: 5,914,779 
Kalshoven [45] Date of Patent: Jun. 22,1999 
[54] PORTABLE FLASH LAMP REFLECTANCE 
ANALYZER SYSTEM AND METHOD 
[75] Inventor: James Edward Kalshoven, Seabrook, 
Md. 
[73] Assignee: The United States of America as 
represented by the Administrator of 
the National Aeronautics and Space 
Administration, Washington, D.C. 
[21] Appl. No.: 08/946,062 
[22] Filed: Oct. 7, 1997 
[51] 
[52] 
[58] 
Int. C1.6 ..................................................... GOlN 21/64 
U.S. C1. ......................................... 356/317; 2501458.1 
Field of Search ..................................... 3501326, 328, 
3501317, 318, 417; 2501458.1, 459.1, 461.1, 
461.2 
~561 References Cited 
U.S. PATENT DOCUMENTS 
3,836,782 911974 Forbes et al. ........................ 2501461.1 
4,200,801 411980 Schuresko ............................ 2501458.1 
OTHER PUBLICATIONS 
James E. Kalshoven and David P. Rosten, “An Active 
Optical Remote Sensing System for Vegetation Index Deter- 
mination”, IEEE International Geoscience and Remote 
I 
OBJECT f 3  
Sensing Symposium Remote Sensing for a Sustainable 
Future, IEEE Catalog No. 96CH35875, vol. 111, pp. 
1809-1811, USA, May 27-31, 1996. 
James E. Kalshoven, Airborne Ground Illuminator for 
Hyperspectral Validation and Calibration, SPIE Proceedings 
Earth Observing System, vol. 2820, pp. 67-71, USA, Aug. 
5-6. 1996. 
Primary Examinerq .  L. Evans 
[571 ABSTRACT 
The system and method allow spectroscopic analysis of 
vegetation or the like without effects from changing sun and 
cloud conditions, undesired portions of the area of interest or 
atmospheric disturbances. The system (1) includes a light 
source (5 )  such as a xenon flash lamp, a telescope (7), a 
spectrometer (9), an analogidigital converter (l l) ,  a memory 
(13), a display (15), and an on-board microprocessor (17) or 
a port (19) for attachment to a laptop computer. The system 
is taken to an area of interest in the woods (step 41), the 
vegetation is illuminated from below (step 43) and data are 
taken (step 45). 
9 Claims, 2 Drawing Sheets 
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TAKE SYSTEM TO 
LOCATION 
Jun. 22,1999 
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- 1  r _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ - - - -  I SPECTROMETER I 
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Fig. 5 
BANDWIDTH OUT 
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ANALYZE FLOURESCENCE I WITHIN BANDWIDTH 
Fig. 6 
The invention described herein was made by an employee 
of the United States Government, and may be manufactured 
and used by or for the Government for governmental pur- 
poses without the payment of any royalties thereon or 
therefor. 
TECHNICAL FIELD 
The invention is directed to a system and method for the 
study of a scene containing objects such as vegetation or the 
like by spectral analysis of reflected light. 
BACKGROUND ART 
5,914,779 
1 2 
PORTABLE FLASH LAMP REFLECTANCE 
ANALYZER SYSTEM AND METHOD 
ORIGIN OF THE INVENTION 
coaxial manner which allows the spectrometer to view the 
scene illuminated by a flash from the flash lamp and collect 
the backscattered light energy. The system is compact so it 
can be taken conveniently out of a laboratory and used in a 
s field or forest. Alinear array of detectors is used at the output 
of the spectrometer. The light, before falling on these 
detectors, is spread out or dispersed by the spectrometer 
optics in a manner dependent on the parameters set for the 
spectrometer and desirable for the output needed. Once the 
i o  system is manufactured, it is useful to calibrate the spec- 
trometer so that the spectrometer optics and the linear array 
are in correct positions relative to each other to allow the 
taking of valid data. For example, a manufacturing defect 
may cause light of a certain wavelength to fall on a photo- 
is detector other than the one intended to detect that 
wavelength, in which case the data taken will be invalid; in 
such a case, correction is necessary. Of course, the wave- 
length range that the system can detect should correspond to 
The most common method for determining the most the wavelength range of interest in the intended use. Many 
20 or few wavelengths can be incident on each detector in the popular plant parameters is to use a specially configured, hand-held light detector sensitive to the sun. The user carries array, the total being a continuous spectrum Over a selectable 
such a hand-he1d device through a forest after having wavelength range. Spectral blocking filters can also be used 
be sought at various non-filtered wavelengths in the back- solar radiation transmitted through the canopy is recorded. 
zs scattered light. The system has built in electronics or can be 
effects generated computer controlled, for data acquisition and for calibration 
branches, since both leaves and branches light. using a reference target of known spectral reflectance char- 
Moreover, changing sun and cloud conditions limit the time acteristics, The spectral output, which is the basic data 
in which valid data can be taken before it becomes necessary product of the system according to the present invention, 
to take new reference data in the clear-to the sky field. 30 allows users to more precisely apply spectroscopic opera- 
Aircraft-based instruments using the sun have been used tions developed by scientists based on the reflectance char- 
to study vegetation; however, such instruments have atmo- acteristics of plants, water and soil. It will also aid in 
spheric and sun angle effects to confuse the results. The developing new spectroscopic operations and enhancing 
present inventor has used an aircraft-based detector with a existing ones in fields as diverse as agriculture and forestry. 
flash lamp to take data, but the backscatter from the earth’s 35 These operations can be incorporated into systems according 
surface convolves both soil and leaf undercover and living to the present invention for a more advanced data output. 
plant characteristics. The present inventor’s experiences 
with aircraft-based detectors are described in the papers “An BRIEF DESCRIPTION OF THE DRAWINGS 
Active Optical Remote Sensing System for Vegetation Index 
Determination” by J. E. Kalshoven, et a1 and “Airborne 40 
Ground Illuminator for Hyperspectral Validation and Cali- 
bration” bv J. E. Kalshoven. aresented at conferences of the 
gathered reference data in a clear-to-the-sky and the in front of the flash lamp, and induced fluorescence can also 
One disadvantage Of such a method in 
leaves from effects generated 
A preferred embodiment of the invention will now be 
described in detail with reference to the drawings, in which: 
FIG. 1 shows a block diagram of the system according to 
I I  
IEEE and’SPIE, respectively, in July, 1996. Both of these a Preferred embodiment Of the Present invention; 
papers are hereby incorporated by reference in their entire- 
ties into the present disclosure. 
Fluorescence-based systems use lasers to excite a surface. 
Such systems must be custom-designed for specific appli- 
cations in laboratory settings. 
FIG. 2 shows details of a spectrometer used in the system 
FIG. 3 shows details of a light source used in the system 
FIG. 4 shows an external view of the system according to 
45 of FIG. 1; 
of FIG. 1; 
the preferred embodiment; 
so FIG. 5 shows a flow chart of a method of using the system STATEMENT OF THE INVENTION - 
It is an object of the invention to provide a system and 
method for spectroscopic analysis of a scene containing 
objects such as vegetation or the like with reduced depen- 
dence on sun and cloud conditions, atmospheric effects, sun 
angle effects and backscatter from the earth’s surface. 
It is a further object of the invention to provide such a 
the taking of data from leaves with reduced interference in FIG, 1, system 1, used to data from object 3, includes 
60 flash lamp or other light source 5,  such as a xenon lamp or from branches. 
It is a further object of the invention to provide such a a photographer’s flash gun, mounted next to telescope 7 
system and method which allow the use of Portable equip- which receives the reflected light from the flashes off of the 
and which do not have to be custom-designed for any surface of object 3. Light source 5 and telescope 7 are 
specific application. located very close together and are preferably coaxial. Such 
To achieve these and other objects, the invention is 65 an arrangement avoids shadows. The light from telescope 7 
directed to a system including a flash lamp and a is sent through spectrometer 9 where it is spread out spec- 
spectrometer, with appropriate optics, configured in a trally onto the surface of a linear detector array, such as a 
of FIG. 1; and 
method of using the system of FIG, 1, 
FIG, 6 shows a flow chart of steps used in a modified 
DETAILED DESCRIPTION OF THE 
INVENTION 
55 
system and method which, when used with vegetation, allow A system according to the preferred embodiment is shown 
5,914,779 
3 
CCD array. The field of view is variable if desired. The 
output of the array is fed to analogidigital converter 11, and 
the spectral information is either stored in memory 13, 
displayed on display 15 or both. The data can be analyzed 
either by dedicated microprocessor 17 or by a laptop com- 
puter connected by way of a port (such as serial port 19, a 
parallel port, or a PCMCIA slot). 
Spectrometer 9 is shown in greater detail in FIG. 2. Light 
entering spectrometer 9 is made incident on dispersing 
optical element 31, which may be a prism, a diffraction 
grating, a holographic optical element or any other suitable 
element. The light dispersed by dispersing optical element 
31 is made incident on linear detector array 33, which, as 
noted above, may be a CCD array. 
Light source 5 is shown in greater detail in FIG. 3. Light 
source 5 includes lamp 35 such as a xenon flash lamp and 
optionally also includes spectral filter 37 for fluorescence 
data acquisition. 
An external view of the system is shown in FIG. 4. 
Hand-held portion 61 has a band strap 63 and is connected 
via cable 65 to main portion 67, which has a waist strap 69 
for attachment to the user’s waist. Hand-held portion 61 
contains a light source 5 and telescope 7. Hand-held portion 
61 may also contain a spectrometer 9, in which case cable 
65 is an electrical cable; alternatively, spectrometer 9 may be 
in main portion 67, in which case cable 65 is a fiber optic 
cable. Either way, the system should take up no more than 
one cubic foot. 
The use of system 1 will now be explained with reference 
to the flow charts of FIGS. 5 and 6. In step 41, the user 
carries the system to a location of interest, such as a 
particular location in a forest. In step 43, the user illuminates 
the area of interest, such as the vegetation to be analyzed, 
preferably while holding the system stationary. The illumi- 
nation is done preferably from below, thus avoiding effects 
from the ground. In step 45, the data are taken from the 
reflected light. 
FIG. 6 shows steps in a modification used for studying 
fluorescence effects of the vegetation. In step 51, a band- 
width is filtered out of the illuminating light by means of 
filter 37 or the like. In step 53, fluorescence is analyzed 
within that bandwidth. Thus, the effects observed are known 
to be caused by fluorescence rather than simply by reflec- 
tion. 
While a preferred embodiment of the present invention 
has been set forth, it will be readily apparent to those skilled 
in the art who have studied this specification that the system 
and method may be modified without departing from the 
present invention. For example, as part of the analysis, ratios 
of different parts of the spectrum may be taken in a pre- 
scribed manner, according to operations known in the sci- 
entific literature. Also, the system could be used with a 
global positioning system. Therefore, the present invention 
should be construed as limited only by the appended claims. 
S 
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I claim: 
1. A method of using a system for spectroscopic analysis 
illuminating means for emitting light in at least an upward 
direction for illuminating the object of interest; 
telescope means for receiving a portion of the light which 
is reflected from the object of interest; and 
spectrometry means for spectroscopically analyzing the 
portion of the light which is received by the telescope 
means to perform the spectral analysis of the object of 
interest, the method comprising: 
(a) transporting the system to a location adjacent to the 
object of interest; 
(b) illuminating the object of interest at least from 
below with the illuminating means; 
(c) receiving the portion of the light reflected by the 
object of interest with the telescope means; and 
(d) performing the spectral analysis with the spectros- 
copy means in accordance with the portion of the 
light. 
2. A method as in claim 1 wherein the location is 
substantially below the object of interest. 
3. A method as in claim 1, wherein the object of interest 
comprises living vegetation. 
4. A method as in claim 1, wherein step (b) comprises 
equipping the illuminating means with a spectral filter which 
removes a bandwidth so that the light used to illuminate the 
object of interest is spectrally filtered. 
5 .  A method as in claim 4, wherein step (d) comprises 
performing the spectral analysis on wavelengths of the 
portion of the light within the bandwidth to analyze fluo- 
rescence in the object of interest. 
6. A method as in claim 1, wherein the system is held 
stationary during step (b). 
7. A system for spectroscopic analysis of an object of 
interest, the system comprising: 
illuminating means for emitting light in at least an upward 
direction for illuminating the object of interest at least 
from below; 
telescope means for receiving a portion of the light which 
is reflected from the object of interest; and 
spectrometry means for spectroscopically analyzing the 
portion of the light which is received by the telescope 
means wherein said illuminating means, telescope 
means, and spectrometry means are located within a 
housing comprising a hand-held portion and a main 
portion, these portions being connected to each other 
via a cable. 
8. A system as in claim 7 wherein the hand-held portion 
houses the illuminating means and the telescope means, the 
main portion houses the a spectrometry means, and the cable 
connecting them is a fiber optic cable. 
9. A system as in claim 7 use in which the hand-held 
portion houses the illuminating means, the telescoping 
means, and the spectrometry means. 
of an object of interest, the system comprising: 
* * * * *  


Portable flash lamp reflectance analyzer system and method

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