compiled john l, kaltenbach - nasa · l i. the rat\ onale gcverni ng the select1 on of certain...

$: Compiled John L, Kaltenbach - NASA · l i. THE RAT\ ONALE GCVERNI NG THE SELECT1 ON OF CERTAIN WAVELENGTH BANDS FOR USE IN OBTAI NI NG AERIAL AND S PACE PHOTOGRAPHY UNDER THE NASA$
*.

N A S A T E C H N I C A L - NASA IM X-1947 M E M O R A N D U M .-

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APOLLO 9 MULTISPECTRAL PHOTOGRAPHIC INFORMATION

Compiled by John L, Kaltenbach

Manned Spacecraft Center Hozcston, Texas

NATIONAL AEROUAUTICS AND SPACE ADMINISTRATION I WASHlWGTON, D. C. * APRIL 1978

https://ntrs.nasa.gov/search.jsp?R=19700013371 2020-07-05T08:42:31+00:00Z

APOLLO 9 MULTISPECTRAL PHOTOGRAPHIC INFORMATION

Manned Spacecraft Center Houston, Texas 77058

National Aeronautics and Space Administration Washington, D. C. 20546 Technical Memorandum

provided orbital photography of the earth. The photography was taken by four cameras, each of which contained a different film-filter combination. Special color viewing and reproduction systems a r e being used to determine the use and value of multispectral photography to the earth resources disciplines and to apply these findings to the design of future imaging systems.

' Multispectral ' Earth Resources Unclassified - Unlimited

C T H I S REPORT) (THIS PAGE)

I I

*For sale by the Clearinghouse for Federal Scientific and Technical Information Springfield, Virginia 22151

CONTENTS

Section

. . . . . . . . . . . . . . . . . . . . . . . . . . I INTRODUCTION

Page

1

By Robert 0. Piland

I1 THE RATIONALE GOVERNING THE SELECTION O F CERTAIN WAVELENGTH BANDS FOR USE IN OBTAINING AERIAL ANDSPACEPHOTOGRAPHYUNDERTHENASAEARTH

. . . . . . . . . . . . . . . . . . RESOURCES SURVEY PROGRAM

By Robert N. Colwell

I11 GENERAL INFORMATION ON NASA EXPERIMENT SO65 MULTISPECTRAL PHOTOGRAPHY . . . . . . . . . . . . . . . . . . 11

By Paul D. Lowman

IV SUGGESTIONS FOR MULTISPECTRAL PHOTOGRAPHY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A N A L Y S I S . . 29

By Edward Yost and Sondra Wenderoth

TABLES

Table Page

11-1 CONVENTIONAL WAVELENGTH RANGES . . . . . . . . . . . . . . . . 7

11-11 OPTIMUM WAVELENGTHS FOR PHOTOGRAPHING NATURAL PHENOMENA . . . . . . . . . . . . . . . . . . . . . . . . 8

111-1 PHOTOGRAPHIC INDEX O F EXPERIMENT SO65 MULTISPECTRAL PHOTOGRAPHS . . . . . . . . . . . . . . . . . . 22

FIGURES

Figure Page

11- 1 Relative sensitivity as a function of photographic film-filter combination

(a) Panatomic-X type 3400 film, Photar 25A red and Photar 58 green f i l t e rs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

(b) Aerographic type SO-246 infrared film (black and white), Photar 89B dark r ed f i l t e r . . , . . . . . . . . . . . . . . . . . . 10

(c) Ektachrome type SO- 180 infrared film (color), Photar 15 orange f i l ter . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

111-1 Experiment SO65 camera arrangement relative to flight path . . . . . . 14

111-2 Apollo 9 Experiment SO65 multispectral photography index map (southwestern United States, northwestern Mexico, south central and southeastern United States, and southern Mexico) . . . . . . . . . . . . . . . . . . . . . . . . . , . .. . . . , . 15

111-3 Apollo 9 Experiment SO65 multispectral photography index map (Caribbean-Atlantic region) . . . . . . . . . . . . . . . . . . . . . . 16

111-4 Examples for the NASA Experiment SO65 multispectral photography on Apollo 9

(a) Photograph NASA AS9-26A-3699A taken with Ektachrome type SO- 180 infrared ae r i a l fi lm (color) with a

-- -

Photar 15 orange fil ter . . . . . . . . . . . . . . . . . . . . . . 17 (b) Photograph NASA AS9 - 26B- 3699B taken with Panatomic-X

type 3400 aer ia l fi lm (black and white) with a Photar 58 green fil ter . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

(c ) Photograph NASA AS9-26D-3699D taken with Panatomic-X type 3400 aer ia l fi lm (black and white) with a Photar 25A red f i l t e r . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Figure Page

(d) Photograph NASA AS9-26C- 3699C taken with Aerographic type SO-246 infrared film (black and white) with a

. . . . . . . . . . . . . . . . . . . . Photar 89B dark red f i l ter 17 (e) NASA AS9 .26A.3699A . Iniperial Valley of California and

Mexico, Colorado River. Gila River. All-American Canal. . . . . . . . . . . . . . . . . . . . . . . . . . Giant Sand Dunes 18

( f ) NASA M9-26B-3699B . . . . . . . . . . . . . . . . . . . . . . . . 19 (g) NASA AS9-26D-3699D . . . . . . . . . . . . . . . . . . . . . . . . 20 (h) NASAAS9-26C-3699C . . . . . . . . . . . . . . . . . . . . . . . . 21

IV- 1 Projector arrangement for additive color interpretation of . . . . . . . . . . . . . Experiment SO65 multispectral photography 33

. . . . . . . . . IV-2 Top view of an additive color projection arrangement 33

. . . . . . . . . . . . . . . . . . . . . . . . IV- 3 Fi l ter -holding apparatus 34

IV-4 An alternate projection arrangement . . . . . . . . . . . . . . . . . . 34

I. INTRODUCTION

By Robert 0. Piland Act ing Chief, Earth Resources Div is ion

NASA Manned Spacecraft Center Houston, Texas

The Apollo 9 multispectral cameras provided 127 f rames of photography in four different bands of the visible and near-infrared portions of the spectrum. These cam- e r a s provided the f i r s t NASA multispectral photography of the earth taken from an orbiting spacecraft.

The purpose of this document is to explain the four-camera experiment (hereafter referred to a s Experiment S065), to discuss the method the investigators plan for use and analysis of multispectral photography, and to provide an index of the photography. Since the major advantage of multispectral photography is realized when the reflectivity of an object can be compared simultaneously in two o r more portions of the spectrum, the last section of this document demonstrates a method whereby a simple and inexpen- sive additive color viewer can be constructed.

Investigators in the NASA Earth Resources Program may obtain duplicates of the Apollo 9 rnultispectral photography by writing to the Earth Resources Division, NASA Manned Spacecraft Center (MSC), Houston, Texas. All other requests for this photography may be made to the following address:

Technology Application Center University of New Mexico Albuquerque, New Mexico 87 106

l i . THE RAT\ ONALE GCVERNI NG THE SELECT1 ON OF CERTAIN

WAVELENGTH BANDS FOR USE I N OBTAI N I NG AERIAL AND

S PACE PHOTOGRAPHY UNDER THE NASA EARTH

RESOURCES SURVEY PROGRAM

By Robert N. Colwel l Forestry Remote Sens ing Laboratory

Un ivers i t y of Ca l i fo rn ia Berkeley, Ca l i f o rn i a

The energy sensed when obtaining aer ia l o r space photography of the ear th surface is electromagnetic radiative energy. The pr imary source of electromagnetic radiative energy is the sun, which illuminates objects on the ear th surface. These objects reflect the illuminated energy, which is sensed when the objects a r e photographed.

Electromagnetic energy travels in a wavelike motion, and the distance f rom one wave c re s t to the next is termed the wavelength. Typically, a beam of electromagnetic energy is composed of many wavelengths comprising a spectrum. The energy spectrum used in obtaining aer ia l and space photography of the ear th surface is comprised of wavelengths ranging f rom approximately 400 to 900 millimicrons. Because of excessive scattering by haze particles, wavelengths shorter than 400 millimicrons can rarely be used when taking aer ia l o r space photography of the ear th surface. This phenomenon is related to Rayleigh's law. Wavelengths longer than approximately 900 millimicrons can ra re ly be used because of the problems involved in preparing thermostable photographic emulsions of sufficiently fine grain size.

The 400- to 900-millimicron range of wavelengths embraces a l l colors of the visible spectrum (violet, indigo, blue, green, yellow, orange, and red) together with wavelengths slightly longer than the visible red region of the spectrum, known a s the near- infrared region. The 400- to 900-millimicron range is composed of four wavelength bands, of which three a r e in the visible region and one is in the infrared region of the spectrum. The three visible bands correspond to the three pr imary colors: blue, green, and red. The wavelengths embraced by the four bands a r e approximately a s follows:

Band Wavelength range, my

Blue 400 to 500

Green 500 to 600

Red 600 to 700

Infrared 700 to 900

An aer ia l o r space photograph can be taken in any one of these bands by (1) using a photographic fi lm sufficiently sensitive to energy in that band and (2 ) using a fi l ter which, while transmitting energy within that band, effectively excludes energy of a l l other wavelengths to which the fi lm i s sensitive.

To determine the most appropriate wavelength bands for taking ae r i a l o r space photography of the ear th surface, two factors require consideration: (1) the degree to which objects on the ear th surface reflect energy in the bands being considered and (2) the extent to which radiant energy f rom the bands i s scattered by haze part ic les in the atmosphere. (The sharpness of the photographic image var ies inversely with the amount of radiant energy scat tered by the atmosphere. ) In the following discussions, these two factors a r e discussed separately.

ENERGY REFLECTANCE FROM THE OBJECTS TO BE PHOTOGRAPHED

As previously stated, only the energy reflected by objects i s used in photography. An increase in the energy reflected by an object to the camera in a given wavelength band causes an increase in the image brightness of the object photographed in that band. (That is, the object will display a lighter tone on the photographic positive. ) Since the amount of energy reflected in a given band tends to be a function of the type of object, the tones obtained (object by object) when photographing in that band a r e important a ids in the identification of the object.

In many instances, two types of objects may contain essentially the s a m e r e - flectivity in one band, but different reflectivities in another band; that i s , each type of object tends to exhibit a unique "tone signature" in multispectral photography. This tone signature is of great value in identifying the object.

The shape and texture of an object can also be used by the photographic interpre- t e r as an identification aid. However, other fac tors being equal, the higher the alt i- tude f rom which an aer ia l o r space photograph is taken of the earth surface, the l e s s detail of the object shape and texture can be seen. The inverse relationship of altitude to detail means that for high-altitude photographs, the photographic interpreter o r the image-analyzing machine must rely on the tone signature for object identification.

ENERGY SCATTER I NG B Y HAZE PARTI CLES I N THE ATMOS PHERE

For haze particles of the s i ze commonly encountered in the ear th atmosphere, energy scattering conforms to Rayleighf s law, which s ta tes that energy scattering i s inversely proportional to the fourth power of the wavelength of that energy. Since energy scattering causes a loss of image sharpness, short-wavelength bands (e. g . , the blue band) a r e of l e s s value when aer ia l o r space photographs a r e taken of the ear th surface. Consequently, the blue band was not recommended for use in the Ex- periment SO65 multispectral photography.

SPEC I FIC APPLICATIONS OF MULTI BAND PHOTOGRAPHY

To summarize the information presented previously, the following points should be made.

1. The wavelength range of the electromagnetic spectrum that i s normally considered for direct photographic sensing of the earth surface is approximately 400 to 9 00 millimicrons.

2. The 400- to 900-millimicron range is comprised of four bands commonly called the blue, green, red, and infrared bands.

3. Most of the energy that characterizes any one of the four bands is derived f rom the central portion of that band.

4. The total energy spectrum is a continuum; therefore, each band overlaps a neighboring band. Consequently, various authorities disagree on the precise limits of each band. Such disagreement should cause no concern if the wavelengths comprising the central portion of each band a r e established. Table 11-1 provides three authorita- tive expressions of the wavelength range encompassed by each of the four bands. Table 11-11 indicates the photographic identification that can be accomplished by using the four bands. Figure 11-1 provides the approximate spectral relative sensitivity of the film-filter combinations used on Experiment SO65 (refs . 11- 1 and 11-2). Of the three diagrams comprising figure 11- 1, figure 11- l(c) shows the effective sensitivity of Ektachrome infrared film when used in conjunction with a Photar 15 orange filter, a s on Experiment S065. An important objective of the experiment consists of determining whether more information is obtained by color combining the three black and white photographs than can be obtained from the matching Ektachrome infrared photograph. (One means of color combining is described in section TV of this report. ) Because of the unusual colors with which features a r e rendered on Ektachrome infrared film, it is important that the unique properties of this film, a s described in the following para- graphs, a r e understood. Emphasis is given to explaining why healthy vegetation ap- pears red on photography taken with this film.

Ektachrome infrared type SO- 180 is known a s a "subtractive reversal" color film. In such a film, the dye responses, when the film is processed, a r e inversely proportional to the exposures received by the respective emulsion layers. In devising Ektachrome infrared film, the manufacturers had one major objective in mind - that of causing healthy vegetation to exhibit a strong photographic color contrast with respect to al l other features. More specifically, it was decided that a subtractive- reversal photographic filni should be devised on which healthy vegetation would appear bright red, while everything else would appear in colors other than red. To accom- plish this objective, it was necessary to exploit the fact that healthy vegetation ex- hibits very high infrared reflectance and relatively low visible-light reflectance. Thus, when the manufacturers were devising the three-layer emulsion of Ektachrome infrared film, they linked a cyan dye to the infrared-sensitive layer of the film, and they linked yellow and magenta dyes to the green- and red-sensitive layers, respectively.

Consistent with the foregoing and with the reminder that the dye responses a r e inversely proportional to the exposures received, t h e following responses occur in each a r e a of the Ektachrome infrared film on which healthy vegetation is imaged: (1) A large amount of the yellow and magenta dyes a r e left in the fi lm af ter processing, because the fi lm is only weakly exposed to r ed and green wavelengths to which the yellow and magenta dyes, respectively, a r e linked; and (2) little o r no cyan dye is left in the fi lm af ter processing because the f i lm is strongly exposed by infrared wavelengths to which the cyan dye is linked.

When the processed Ektachrome infrared film, in transparency form, i s viewed over a light table through w h i c h white light is shining (i. e , , light which contains approximately equal amounts of blue, green, and red), the following fac tors a r e opera- tive in the pa r t s of the transparency where healthy vegetation is imaged: (1) The concentration of yellow dye is so high that blue light is almost completely absorbed, (2) the concentration of cyan dye is so high that green light is a l m o s t completely absorbed, and (3) the concentration of magenta dye is so low that r ed light is almost completely transmitted. The net resul t of these fac tors is to cause the healthy vegetation to appear red. Since virtually no other fea tures have this peculiar combination of spectral reflectances, no other features appear red on the transparency.

REFERENCES

11-1. Colwell, R. N . , et a l . : An Evaluation of Earth Resources Using Apollo 9 Photog- raphy. (Final report by the Forestry Remote Sensing Laboratory, School of Forestry and Conservation, Univ. of California, under NASA contract NAS 9-9348), Sept. 30, 1968.

11-2. Keenan, P. B. ; and Slater, P. N. : Preliminary Post-Flight Calibration Report on Apollo 9 Multiband Photography Experiment S065. Technical Memoran- dum 1, Optical Sciences Center, Univ. of Arizona, Tucson, Ar i z . , Sept. 12, 1969.

TABLE 11-1. - CONVENTIONAL WAVELENGTH RANGES

a ~ a r t h Resources Technology Satellite.

Band

Blue

Green

Red

Infrared (near infrared)

Wavelength range, mp

Elementary physics

400 to 500

500 to 600

600 to 700

700 to 900

Apollo 9 Experiment SO65

- -

480 to 620

590 to 720

720 to 900

Proposed

for E R T S ~

- -

475 to 575

580 to 680

690 to 830

TABLE 11-11. - OPTIMUM WAVELENGTHS FOR

PHOTOGRAPHING NATURAL PHENOMENA

Photograph identification

Presence o r absence of vegetation

Differentiation of conifers f rom broadleaf vegetation

Identification of individual plant species

Detection of ear l ies t evidence of loss of vigor in vegetation

Identification of agent that causes loss of vigor

Determination of the exact course of a meandering s t ream channel

Acquisition of maximum underwater detail (var ies with turbidity)

Determination of maximum detail in shaded a r e a s on low -altitude photographs only

Identification of geologic formations

Differentiation of urban a r e a components

Optimum wavelength band

%lo earth-orbital sensing in the blue band is contemplated because of excessive scattering of short wavelengths by atmospheric haze particles.

- Panatomic-X type 3400 f i lm --- Photar 25A f i l t e r r l

Photar 58 f i l te r 1 I I I r I

Wavelength, m~

(a) Panatomic-X type 3400 f i lm, Photar 25A r ed and Photar 58 green f i l ters .

Figure 11-1. - Relative sensitivity a s a function of photographic film-filter combination.

5 I n f r a red Aerographie type SO-246 f i lm (black and wh i t e i n f r a red )

4 Pho ta r 89B f i l t e r

3

2

1

0 300 400 500 600 700 800 900

Wavelength, r n ~

(b) Aerographic type SO-246 infrared film (black and white), Photar 89B dark red f i l t e r .

300 400 500 600 700 800 900

Wavelength , m F!

(c) Ektachrome type SO-180 infrared film (color), Photar 1 5 orange f i l ter .

Figure 11- 1. - Concluded.

1 1 1. GENERAL l NFORMATI ON ON NASA EXPER I MENT SO65

MULTI S PECTRAL PHOTOGRAPHY

By Paul D. Lowman NASA Goddard Space Flight Center

Greenbelt, Maryland

The value of color photography taken from an orbiting spacecraft was demonstrated by studies of photography taken of the ear th during flights in the Mercury, Gemini, and early Apollo programs. The value of multispectral aer ia l photography in many fields has been demonstrated over the last several years . Experiment SO65 flown on Apollo 9 was the first attempt to obtain multispectral photography f rom space and, thus, to combine the benefits of color photography and multispectral photography to remote sensing.

The purpose of Experiment SO65 was to obtain simultaneous photographs of the ear th from space, using four different spectral sensitivities (film-filter combinations) and a four-camera assembly mounted in the Apollo spacecraft hatch window (fig. 111-1). The specific objectives of the experiment were (1) to investigate the feasibility and value of orbital multispectral photography fo r studies in meteorology and in the ear th resources disciplines of agriculture, forestry, geography, geology, hydrology, and oceanography and (2) to apply the resul ts of the investigation to future manned and un- manned photographic systems design.

EQU l PMENT

Electrically driven Hasselblad cameras, model 500 EL, equipped with the f/2.8 Zeiss 80-millimeter Planar lens, were used for Experiment S065. The cameras were modified for space use by the Hasselblad Company and MSC and were mounted coaxially on a metal bracket designedto fit the circular command module hatch window. The shutters were triggered simultaneously at predetermined intervals (generally between 5 and 1 0 seconds) by a manual electric switch controlled by the astronaut taking the photograph.

The following film-filter combinations were used:

1. Infrared Ektachrome type SO-180 film (color infrared), with a Photar 15 fil ter, sensitive in the 510- to 900-millimicron range

2. Panatomic-X type 3400 film (black and white panchromatic), with a Photar 58 f i l ter , sensitive in the 460 - to 610-millimicron range

3. Infrared Aerographic type SO-246 film (black and white infrared), with a Photar 89B fil ter, sensitive in the 700 - to 900 -millimicron range

4. Panatomic-X type 3400 f i lm (black and white panchromatic), with a Photar 25A fil ter, sensitive in the 580-n~ill imicron to infrared range

METHOD OF OPERAPI ON

The following main steps were performed by the flightcrew for each Experi- ment SO65 photographic pass:

1 . Unstow and install the camera unit in the hatch window.

2. Orient the spacecraft vertically according to ground instructions.

3. Place the spacecraft in an orbital ra te mode (to keep the spacecraft pointed in a given direction relative to the earth).

4. Take photographs beginning and ending a t t imes specified by the Mission Control Center, Houston, Texas.

5. Record the ground elapsed time of the f i r s t exposure and the number of exposures in each sequence.

6. Terminate the orbital ra te mode and stow the cameras (unless a second pass is scheduled subsequently).

The cameras were preset so that no adjustnients by the flightcrew were necessary. Since the earth surface was visible through the side windows when the hatch window was parallel to the surface during several of the Experiment SO65 passes , the flightcrew was able to take nearly sinlultaneous terrain photographs using the hand-held Hasselblad 500C camera loaded with Ektachronle SO-368 film.

RESULT

The flightcrew encountered no difficulty in conducting Experiment SO65 and taking photographs during five passes over North America. The number of photographs obtained for each film type was a s follows: Panatomic-X (both magazines), 159 photographs per magazine; infrared Aerographic, 127 photographs per magazine, and infrared Ektachrome, 139 photographs per magazine. The number of complete four- camera se t s is 127. The regions photographed included southwestern United States (south of 34" north latitude), northwestern Mexico, south central and southeastern United States, southern Mexico, and the Caribbean-Atlantic region (figs. 111-2 and 111- 3).

Experiment SO65 was extremely successful, both in the quality and in the quan- tity of the photography obtained (fig. 111-4). During the five passes over North America and the adjacent ocean areas , 372 photographs (the four-camera total) showing a

significant portion of the cloud-free landmass were obtained. The quality of a l l the photographs ranged f rom very good to excellent. A few f r ames taken of northern Chihuahua, Mexico, appeared to be slightly overexposed, but this condition probably resulted from a high sun angle and a bright deser t terrain, together with the fixed setting. Several of the NASA test s i tes , including those in the Imperial Valley and Phoenix, Arizona, were photographed a t about the same time that a i rcraf t underflights were being flown. A wide variety of terrain, including the Colorado, Yuma, Chihuahua, and Senora Deserts ; the forested mountains; the Great Plains; the Mississippi Valley; the southern Appalachians and the adjacent Piedmont; and the southeastern Coastal Plain, was photographed. The climatic-seasonal range (caused by elevation differences) spans early summer to winter with many regions remaining partly snow covered. Several large cit ies (including San Diego, California; southern Los Angeles, California; Phoenix, Arizona; Atlanta, Georgia ; and Birmingham, Alabama) were photographed. The Experinlent SO65 photography taken during the Apollo 9 mission has scientific value for i t s a r ea l coverage, scale , and general quality alone. However, the fact that the photography was taken a s pa r t of a systematic multispectral experiment with simultaneous underflights by NASA Earth Resources Program a i rc raf t greatly increases i t s value. The current detailed analysis of Experiment SO65 photography and supporting data is expected to be substantially beneficial to the Earth Resources Survey Program. A list of a l l the photographs taken during Experiment SO65 is given in table 111-1.

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(a) Photograph NASA AS9 -26A- 3699A taken with Ektachrome type SO-180 infrared aerial film (color) with a Photar 15 orange filter.

(b) Photograph NASA AS9-26B-3699B taken with Panatomic-X type 3400 aerial film (black and white) with a Photar 58 green filter.

(e) Ph8twm MA M0 -2m- $69933 WEB wi& Panatwic-S type $400 amiaI film &LC& W whX&) w3th a P h W 262% red Bltm a

(d) Photograph NASA AS9- 26C-3699C taken with Aerographic type 50-246 infrared film (black and white) with a Photar 89B dark red filter.

(e) AS9 -26A-3699A. Imperial Valley of California and Mexico, Colorado River, Gila River, All-American Canal, Giant Sand Dunes.

Figure In-4. - Continued.

(f) AS9 -26B-3699B.

Figure 111-4. - Continued.

(g ) NASA AS9 -26D-3699D.

F igure 111-4. - Continued.

(h) NASA AS9-26C-3699C.

Figure 111-4. - Concluded.

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asa

Cra

nd

e, a

nd s

ou

th o

f P

hoen

ix

Ari

zon

a:

Cas

a G

ran

de

and

Wil

liam

s

Ari

zon

a:

Wil

liam

s

Ari

zon

a:

Wil

liam

s

Ari

zon

a:

Tu

cso

n

Ari

zon

a:

W~

llco

x Lak

e

Ari

zon

a:

Wil

lcox

Lak

e

New

M

exic

o an

d M

exic

o b

ord

er,

sou

thw

est

of

Dem

ing

New

Me

x~

co

and

Mex

ico

bo

rder

, so

uth

of

Dem

ing

New

M

exic

o an

d M

exic

o b

ord

er,

sou

th o

f D

emin

g

Mex

ico

and

Tex

as b

ord

er,

sou

thw

est

of

El

Pas

o

Mex

ico

and

Tex

as,

sou

th-s

ou

thw

est

of E

l P

aso

Tex

as:

Rio

Gra

nd

e V

alle

y an

d Q

ult

man

Mou

ntai

ns

Mex

ico:

S

ierr

a S

an M

arti

n D

el B

orr

ach

o

Tex

as:

Rio

Gra

nd

e V

alle

y N

orm

al

No

rmal

No

rmal

No

rmal

No

rmal

Tex

as:

Rio

Gra

nd

e V

alle

y an

d V

an H

orn

Tex

as:

Van

Hor

n an

d P

eco

s

Tex

as:

Van

Ho

rn.

Pec

os,

an

d R

ed B

luff

Lak

e

Tex

as:

Pec

os

and

Red

Blu

ff L

ake

a~

pe

rati

on

al N

avig

atio

nal

Ch

art;

Wor

ld A

ero

nau

tica

l C

har

t.

TA

BL

E 1

11-1

. - P

HO

TO

GR

AP

HIC

IN

DE

X O

F E

XP

ER

IME

NT

SO

65 M

UL

TIS

PE

CT

RA

L P

HO

TO

GR

AP

HS

- C

onti

nued

[Fro

m m

agaz

ine

AS^

-261

ON

C

WA

C

nu

mb

er

(a )

- C

loud

co

ver

, p

erce

nt

0 0 0 1 2 2 5

99

I5

I 20

40

30

40

45

10

10

10

0 1

3 5

25

35

40

35

30

35

~lt

ikd

e,

n.

mi.

10

5

10

5

10

5

10

5

10

5

10

5

10

5

106

106

106

106

10

6

106

10

5

10

5

10

5

10

5

10

5

10

5

10

5

10

3

10

3

10

3

10

3

10

3

10

3

Fra

me

3: n

um

ber

M

arch

3723

Sun

el

eva-

ti

on

, de

g -

54

54

54

54

54

54

Des

crip

tio

n

Pri

nci

pal

poi

nt

Tex

as:

Au

stin

, P

ort

Lav

aca,

an

d B

eev

ille

Tex

as:

Po

rt L

avac

a an

d M

atag

ord

a B

ay

Tex

as:

Mat

ago

rda

and

Eag

le L

ake

Tex

as:

Mat

ago

rda,

E

agle

Lak

e,

and

Fre

epo

rt

Tex

as:

Mat

ago

rda,

G

alv

esto

n B

ay,

and

Hou

ston

Tex

as:

Mat

ago

rda

and

Gal

ves

ton

Bay

Tex

as:

Gal

ves

ton

and

Fre

epo

rt

Clo

ud

s, u

nin

ten

tio

nal

ly e

xp

ose

d

Cal

ifo

rnia

: S

an C

lem

ente

, S

anta

Cat

alin

a, a

nd

San

ta B

arb

ara

Isla

nd

s:

San

Ped

ro B

ay

Cal

ifo

rnia

: S

an C

lem

ente

and

San

ta C

ata

l~n

a Is

lan

ds,

San

Ped

ro B

ay,

no

rth

ern

San

Die

go

Cal

ifo

rnia

: S

anta

Ana

to

San

Die

go

Cal

ifo

rnia

: S

an D

iego

and

Sal

ton

Sea

Cal

ifo

rnia

: S

alto

n S

ea a

nd I

mp

eria

l V

alle

y

Cal

ifo

rnia

: S

altu

n S

ea a

nd I

mp

erla

l V

alle

y A

rizo

na:

C

ibo

la

New

Mex

ico:

S

oco

rro

and

Car

rizo

zo a

nd l

ava

bed

s

New

M

exic

o:

Car

rizo

zo a

nd l

ava

bed

s

New

M

exic

o:

Rui

doso

and

Ros

wcl

l

Lo

uis

ian

a:

Mon

roe

and

Mis

siss

ipp

i V

alle

y

Mis

siss

ipp

i:

Vic

ksb

urg

, M

issi

ssip

pi

Val

ley

, an

d G

reen

vil

le B

end

Mis

siss

ipp

i:

Vic

ksb

urg

, M

issi

ssip

pi

Val

ley,

G

reen

vil

le B

end,

an

d Ja

ckso

n

Mis

siss

ipp

i:

Jack

son

an

d Y

azoo

Val

ley

Cal

ifo

rnia

: S

anta

Cat

alin

a an

d S

an C

lem

ente

Isl

and

s, S

an P

edro

Bay

re

gio

n,

and

Oce

ansi

de

Cal

ifo

rnia

: O

cean

sid

e

Cal

ifo

rnia

: O

cean

sid

e an

d S

anta

Ysa

beh

Cal

ifo

rnia

: S

alto

n S

ea a

nd

Im

per

ial

Val

ley

Cal

ifo

rnia

: S

alto

n S

ea a

nd

Im

per

ial

Val

ley

M

exic

o:

Mex

ical

i

Ari

zon

a:

Tu

cso

n

Ove

rlap

, p

erce

nt

80

Lat

itu

de

I 129"

40"

N

29

-26

" N

96

'49"

W

8

0

No

rmal

1 29'22"

N 1 96'

24"

80

I Norm

al

Imag

e ev

alu

atio

n

No

rmal

Lon

gitu

de

97'1

5"

W

/ 29'1

6"

N 1

96"0

8"

W/

8

0

/ N

orm

al

29'0

7"

N

95"4

3"

W

80

N

orm

al

1 29r04

' N

1 95'2

4"

W

80

N

orm

al

j 28.

42"

N

/ 94

-54

'' w

1 8

0

/ N

orm

al

No

rmal

No

rmal

No

rmal

No

rmal

No

rmal

No

rmal

1 45

/ 1

8:02

/ 33

"09"

N

1 117

.50"

w

/ 60

89"5

7"

W

60

No

rmal

11

8~

12

50

1 N

orm

al

1 N

orm

al

No

rmal

No

rmal

No

rmal

No

rmal

No

rmal

No

rmal

No

rmal

No

rmal

No

rmal

No

rmal

50

50

50

55

55

55

No

rmal

a~

pe

ratl

on

al N

avlg

at~

on

al C

har

t; W

orl

d A

ero

nau

tica

l C

har

t.

TA

BL

E 1

11-1

. - PH

OT

OG

RA

PHIC

INDEX O

F E

XP

ER

IME

NT

SO

65 M

UL

TIS

PE

CT

RA

L P

HO

TO

GR

APH

S - C

onti

nued

[Fro

m m

agaz

ine

AS9

-261

a~p

erat

ion

al N

avig

atio

nal

Cha

rt;

Wor

ld A

eron

auti

cal

Cha

rt.

Des

crip

tion

Tex

as:

clou

ds

Tex

as:

Col

lege

Sta

tion

, cl

ouds

Sou

th C

arol

ina:

C

ape

Fea

r,

Myr

tle

Bea

ch,

and

Car

olln

a B

each

Sou

th C

arol

ina:

C

ape

Fea

r an

d C

aro

lma

Bea

ch

Sou

th C

arol

ina:

C

arol

ina

Bea

ch

Mex

ico:

B

aja

Cal

ifor

nia

and

Ens

enad

a

Mex

~co

:Baj

aCal

ifo

rnia

C

olor

ado

Rlv

er d

elta

Mex

leo:

C

olor

ado

Riv

er d

elta

Mex

ico:

C

olor

ado

R~

ve

r delt

a an

d D

es~

ert

o Del

Alt

ar

Mex

lco:

D

es~

ert

o Del

Alt

ar

:&:,

per

cen

t

90

80

10

40

65

30

10

05

0 0

G'm

' '' 14

:42

14:4

3

14:4

7

14:4

7

14:4

7

16:1

4

16:1

4

16:1

4

16:1

5

Fra

me

num

ber

3774

3775

3776

3777

3778

3779

3780

3781

3782

Ove

rlap

, pe

rcen

t

60

50

40

40

40

50

50

50

50

0 1 Me

xico

and

Ar~

zon

a: D

esie

rto

Del

Alt

ar

I 12

6

126

126

115

115

115

106

106

106

116

116

116

133

132

Alt

itud

e,

n.

ml.

126

126

11

3

11

3

113

126

126

126

126

3784

Dat

e in

M

arch

19

69

11

11

11

11

11

11

11

11

11

03

15

35

45

45 0 0 0 0 3 70

80

60

C-1

9 H

-22

G-1

9 H

- 22

G-1

9 H

-22

G-1

9

G-1

9 G

- 20

G-1

9 G

- 20

G-2

0 G

-21

G-2

1

G-2

1

G-2

1

G-2

1

G-2

1

G-1

8

G-1

8

ON

C

WA

C

num

ber

(a)

H-2

3

H-2

3

G-2

1

G-2

1

G-2

1

H-2

2

H-2

2

H-2

2

G-1

8

126

50

Imag

e ev

alua

tion

Dar

k

Dar

k

Nor

mal

Nor

mal

Nor

mal

Dar

k

Dar

k

Nor

mal

Nor

mal

3783

1 A

r~zo

na:

wes

t of

T

ucso

n

An

zon

a:

Tuc

son

and

Cas

a C

rand

e

Tex

as:

Pad

ucah

, no

rth

and

nort

heas

t of

Sny

der

Tex

as:

Kno

x C

~ty

and

Lak

e K

emp

Tex

as:

Red

Riv

er,

Lak

e K

emp,

an

d S

eym

our

Ala

bam

a:

Gad

sden

, A

mis

ton,

an

d M

arti

n L

ake

Ala

bam

a:

Ann

isto

n an

d no

rthe

ast

end

of

Mar

tin

Lak

e

Geo

rg~

a: A

tlan

ta

Sout

h C

arol

ma:

G

eorg

etow

n,

Myr

tle

Bea

ch,

and

Win

yeh

Bay

Sout

h C

arol

ina:

C

ape

Fea

r, c

loud

s,

and

Atl

anti

c O

cean

Sout

h C

arol

ina:

C

ape

Fea

r an

d A

tlan

tic

Oce

an

Cal

do

rn~

a: S

an N

lcol

as I

slan

d

Cal

ifor

nia:

S

anta

Cat

alin

a an

d Sa

n C

lem

ente

Isl

ands

and

San

Cle

men

te

coas

t

G-1

9 H

-22

G-1

8 G

-19

H-2

2

50

Sun

elev

a-

tlon

, de

g 22

22

36

36

36

31

31

31

31

11

Prin

cipa

l

Lat

~tu

de

30°1

5"

N

30'3

0"

N

33'2

8"

N

33"2

5"

N

33'2

3"

N

31-1

9"

N

31'2

8"

N

31'3

4"

N

31'4

2"

N

Nor

mal

3785

3786

3787

3788

3789

3790

3791

3792

3793

3794

3795

3796

3797

-

11

Lo

ng

~tu

de

97-1

0''

W

96*3

0" W

78'2

3"

W

77'5

8"

W

77'2

2"

W

116'

34"

W

115'

42"

W

115-

04"

W

114'

13"

W

31

16:1

5

Nor

mal

Nor

mal

Nor

mal

Nor

mal

Nor

mal

Nor

mal

Nor

mal

Nor

mal

Nor

mal

Nor

mal

Nor

mal

Nor

mal

Nor

mal

Nor

mal

31'5

7"

N

! 31

16

:15

11

11

11

11

11

11

112'

39"

W

31-4

8" N

1

13

-30

W

31

16:1

5

31

16:1

5

38

16:1

8

32'0

6"

N

32'1

4"

N

33'2

0"

N

33'2

2"

N

33'2

6"

N

33'2

7"

N

38

38

47

47

47

39

39

39

25

27

16:1

8

16:1

8

16:2

1

16:2

1

16:2

1

15:O

O

15:O

O

15:O

O

16:2

7

16:2

7

111-

59"

WI 50

I I

11

33"2

3"

N

11

'33

'10

" N

lllc

18

" W

'

100"

41"

W

100'

02"

W

99'3

3"

W

86'0

0"

W

85'1

6"

W

84@

40" W

79'0

3"

W

77'3

9"

W

76'3

0"

W

120'

00"

W

118'

40"

W

12

12

12

12

12

50

50

50

50

60

60

60 5 5 5

7.5

7.5

33'3

5''

N

33"3

5"

N

33"3

0" N

32"5

5"

N

32'5

7"

N

TA

BL

E 1

11-1

. -

PH

OT

OG

RA

PH

IC I

ND

EX

OF

EX

PE

RIM

EN

T S

O65

MU

LT

ISP

EC

TR

AL

P

HO

TO

GR

AP

HS

- C

onti

nued

[Fro

m m

agaz

ine

AS

9-2

61

per

cen

t

1 Fane

1 Dte

1 pr

inci

l:al

'I

oint

I Over

lap

, / It,i,

e 1 cE

:a-

nu

mb

er

Mar

ch

~x

rce

nt

eval

uat

ion

tt

on

. D

escr

ipti

on

Cal

ifo

rnia

: S

an D

iego

, ti

p o

f S

alto

n S

ea,

and

sn

ow

-cap

ped

mo

un

tain

s

Cal

iforn

ia:

Sal

ton

Sea

, Im

per

ial

Val

ley

M

exic

o:

Mex

ical

i

Cal

ifo

rnia

: Y

uma,

B

lyth

e,

Cib

ola

, an

d C

olo

rad

o R

iver

Ari

zon

a:

Ph

oen

ix,

Glo

be,

and

sno

w

Ari

zon

a:

Glo

be

Ari

zon

a:

New

M

exic

o b

ord

er a

nd s

no

w

New

M

exic

o:

no

rth

an

d w

est

of

Ele

ph

ant

Bu

tte

Res

erv

oir

an

d s

now

New

M

exic

o:

Car

rizo

zo,

lav

a fl

ow,

and

sno

w

New

M

exic

o:

Ro

swel

l

New

Mex

ico

and

Tex

as:

bet

wee

n R

osw

ell

and

Lub

bock

Tex

as:

Lub

bock

Tex

as:

Lak

e K

emp

1969

1 3799

/ 12

1 33

-01

N l

115.

18"

w

7 5

No

rmal

1 30

/ 38

00

/ 1

2

1 33

'19"

N

111

3.49

" W

/ 7

.5

! N

orm

al

1 30

Lat

itu

de

No

rmal

No

rmal

No

rmal

No

rmal

No

rniu

l

No

rmal

No

rmal

No

rmal

No

rmal

3798

Lo

ng

~tu

de

Tex

as:

Wic

hit

a F

all

s

Tex

as:

Dal

las,

F

ort

Wo

rth

Tex

as:

Tex

ark

ana

reg

ion

Ala

bam

a:

Ph

oen

ix C

ity

, M

arti

n L

ake,

an

d W

alte

r F

. G

eorg

e L

ake

de

~

98

-37

" W

5

No

rmal

40

96"5

4"

W

3 N

orm

al

41

94'2

3"

W

2 N

orm

al

43

85'4

2"

W

0 )

No

rmal

48

Geo

rgia

: A

mer

icu

s

12

84"1

3"

W

1 82"4

1"

WI 0

No

rmal

1 50

11

6 5

5"

W

33

-01

" N

I

0 N

orm

al

49

, G

eorg

ia:

Way

cro

ss

7. 5

Geo

rgia

: B

run

swic

k

Atl

anti

c O

cean

Atl

anti

c O

cean

: cl

ou

ds

Atl

anti

c O

cean

: cl

ou

ds

No

rmal

29

81

"17"

W

79"4

OV

W

77

"50

" W

76'1

0"

W

0 N

orm

al

51

0 N

orm

al

52

0 ,

No

rmal

53

0

No

rmal

53

Atl

anti

c O

cean

: B

arb

ado

s O

cean

og

rap

hic

an

d M

eteo

rolo

gic

al

Ex

per

imen

t (B

om

ex) a

rea

60

°45"

W

59

"20

M W

58

"05

" W

1 Atl

anti

c O

cean

: D

omex

are

a

/ A

tlan

tic

Oce

an:

Bo

mex

are

a

0 0 0

a~

pe

rati

on

al N

avig

atio

nal

Ch

art;

Wo

rld

Aer

on

auti

cal

Ch

art.

b~

ad

ir

p

oin

t of

c

am

era

.

No

rmal

6

2

No

rmal

6

2

No

rmal

6

2

. . . . . . . . . . . . . . . . . . . . c c 2 . . . . ' . . . . . . . c g g $ $ g $ g $ $ " $ " " c c c c c c C C $i$$$$$$ 8 8 8 8 8 8 8 8 6 : 8 : 8 8 8 8 8 8 8 W

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IV. SUGGESTIONS FOR MULTl SPECTRAL PHOTOGRAPHY ANALYS I S

By Edward Yost and Sondra Wenderoth Long l sland University Greenvale , New York

The NASA Experiment SO65 multispectral photography provides the scientific community the f i r s t simultaneous satellite photography of the ear th sur face in three distinct spectral bands spanning the visible and near-infrared regions of the spectrum. The photography consists of four s e t s of photographs of identical surface locations, taken simultaneously. The images of surface objects appear in the same coordinate positions on al l four photographs in the multispectral set . The multispectral s e t is within the opto-mechanical tolerances of the Hasselblad cameras in the Apollo 9 spacecraft. The s e t of four multispectral photographs is listed in the following table.

Although a sequential o r comparative interpretation of each of the four photographs comprising a multispectral s e t can yield significant information, a substantially more productive analysis can be made by simultaneous additive color viewing. Color viewing of the black and white multiband photographs can be accomplished by an experimenter who has access to a t least three lantern-slide projectors.

Nominal bandpass

Total sensitivity of a l l dye layers , 510 to 900 millimicrons

460 to 610 millimicrons

700 to 900 millimicrons

580 to 700 millirni- crons

>

Mean wavelength of sensitivity

Green, red, and infrared

525 millimicrons, green

800 millimicrons, infrared

645 millimicrons, red

Band (NASA designation)

A

B

C

D

Film and fil ter

Infrared Ektachrome, SO-180, Photar 15

Panchromatic -X, type 3400, Photar 58

Infrared Aerographic type SO-246, Photar 89B

Panchromatic -X, type 3400, Photar 25A

The principles of additive color viewing of aer ia l and space photography a r e quite straightforward, although the experimenter must use ingenuity in order to se t up and operate the equipment. The basic concept is simply that a color-composite image can be produced by optically projecting the positive photographic t ransparencies of images which a r e (1) taken in different pa r t s of the spectrum, (2) projected through different colored f i l ters , and (3) superimposed in accurate registration. The theory and experi- mental details of this technique a r e discussed in detail in appendix 1 of reference IV-1.

A simple arrangement of additive color viewing of the green, red, and infrared black and white multispectral positives is shown in figure IV- 1. Three lantern-slide projectors a r e arranged with their optical axes parallel s o that a projector sc reen placed approximately 10 feet away is illuminated. As indicated in figure Kr- 1, Variacs can be placed in the electrical circuit between the wall outlet and the projectors . Ad- justment of the Variac controls the lamp brightness of each projector. This adjustment allows the experimenter to independently control the relative brightness of each spectral positive on the screen. However, the technique does change the color tone of the projection lamps, tending to make the screen image redder as the brightness is reduced.

Figure IT-2 presents a top view of the additive color projection arrangement. An essential feature of this arrangement is that the optical axes of the projectors a r e parallel and that the middle projector is centered on the screen. To achieve registration, one successful method was to place the red positive transparency in the center projector, with the green and infrared transparencies in the side projectors. By moving the t ransparencies slightly outward in the side projectors, a s shown in figure IV-2, the screen can be placed close to the projector with no differential scale distortion in the image. The image may be made a s bright a s desired by moving the screen closer to the projector.

The procedural s teps successfully accomplished using the additive color projection arrangement a r e a s follows:

1. Arrange the projectors s o that the r e a r legs, the front legs, and the screen a r e parallel. All the projectors should be placed close together.

2. Center the middle projector with respect to the screen and adjust the focus.

3. Place the photography in the lantern slides, making s u r e that the images a r e indexed with respect to the edges of the glass . (This s tep can be accomplished by holding the lantern slides near the light and ascertaining that the images a r e superimposed. )

4. P lace the s l ides in the three projectors. Project the red positive t ranspar- ency in the center projector, using a red fil ter (Photar 25). Then project the green f i l ter (Photar 58). Adjust the green transparency in the projector s o that the images a r e superimposed by the following methods:

a. For the scale adjustment, move the projector lens and projector with respect to the screen. (Only small adjustments should be required i f the projectors have the s a m e focal length lenses. )

b. For the X-axis adjustment (horizontal plane), move the slide-changing mechanism.

c. For the Y=axis adjustment (vertical plane), place a thin layer of masking tape along the bottom of the slide.

d. For the rotational adjustment, tape the bottom of one corner. (The need for taping is minimized by accurately placing the photography in the lantern slides.)

5. Turn off the green projector. Repeat step 4, registering the infrared projector with another green fil ter. (It is difficult to regis ter the images when using the blue fi l ter. ) Remove the green fil ter and replace it with a blue filter. Because of the higher t ransmission property, a Wratten 47A f i l ter ra ther than the standard Wratten 47 fil ter is suggested for the projection arrangement.

6. Turn on the green projector. A well-registered color image should be produced on the screen. This composite image will contain all the colors, including the secondary colors (yellow, cyan, and magenta) and the pr imary colors (red, green, and blue). The hue of the screen image can be adjusted by (a) interchanging f i l ters and (b) using f i l t e rs different f rom those suggested previously. The image brightness can be controlled by Variac adjustment.

Figure IV-3 i l lustrates one possible method for holding the f i l ters on the projector lenses. If Variacs a r e not available, Wratten neutral density f i l t e rs placed with the color f i l t e rs will hold the f i l t e rs on the projector lenses. The following neutral density values for each projector should be sufficient: 0. 1, 0.2, 0. 3, 0. 6, and 0.9. The availability of a fourth projector permits the infrared color transparency to be projected onto another sc reen alongside the multispectral composite color rendition, allowing simultaneous comparison of both images.

If a woodworking shop o r a machine shop is available, a significant improvement in the image registration can be achieved by using the alternate projection arrangement shown in figure IV-4. The projectors a r e secured to a common base plate and placed on end, pointing toward the ceiling. A front surface m i r r o r (not a r e a r surface house- hold mi r ro r ) can be used to deflect the light to the screen. In figure IV-3 the image on the screen may have a "keystone" effect and may not focus sharply throughout the scene. By lowering or tilting the screen this obstacle can be eliminated.

The slide-changing mechanisms a r e removed from the projectors and a r e r e - placed by a common window glass cut to fit in the film gate of the projectors. The three images a r e then mounted in lantern s l ides and placed upon this glass. Because the s l ides a r e held on the glass by gravity, they a r e easily moved to achieve screen image registration.

Photogrammetric plotting equipment, such a s the Kelsh o r multiplex units, can also be used as multispectral viewing equipment. Although image registration should be easy to achieve, the illumination systems may require modification to provide a usable presentation.

REFERENCE

IV-1. Smith, John T. ; and Anson, Abraham, ed. : Manual of Color Aerial Photography. American Society of Photogrammetry, 1968.

Figure IV- 1. - Projector arrangement for additive color interpretation of Experi- ment SO65 multispectral photography.

Green

Red

Infrared

I Variacs Projectors I Figure IV-2. - Top view of an additive color projection arrangement.

Figure IV- 3. - Filter-holding apparatus.

Figure IV-4. - An alternate projection arrangement.

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SPACE ADMINISTRATION

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