Underwater camera enclosure including sonar range finding device

Underwater camera enclosure including sonar range finding device
United States Patent [191
Apr. 26, 1983
[76] Inventor:
References Cited
Nil/402 X
3,237,151 2/1966 Thorpe
Lloyd Breslau, 23 Bobwhite Trail,
Primary Examiner—William B. Perkey
Attorney, Agent, or Firmwweingarten, Sehurgin,
Gagnebin 8L Hayes
Gales Ferry, Conn. 06335
[21] Appl. No.: 283,557
An underwater photographic system which includes an
255 212 IUFmsm.,ma
underwater camera enclosure having an underwater
sonar range-?nding apparatus for providing a signal to
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[58] Field of Search
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354/64, 83, 195, 25 A,
354/126, 129; 352/140, 242; 367/2, 3, 4, 87, 96,
99, 131, 902; 356/3; 181/123, l24, 402
adjust the distance-related parameters of a camera en
closed therein. The enclosure is adapted to house ty '
cally an unaltered commercially available self-develop
ing or “instant” camera speci?cally including a camera
having an air-sonar range-?nding device.
20 Claims, 5 Drawing Figures
U.S. Patent
Apr. 26, .1983
FIG. 3
Sheet 1 of3
era to focus much closer than desired for a particular
underwater subject distance.
Underwater camera housings and enclosures incor
porating acoustic or sonar range-finding devices are
shown in US. Pat. Nos. 3,738,248 and 4,153,357. The
enclosures disclosed therein provide a shutter signal to
trigger a camera having a set predetermined focal dis
tance. In operation, the apparatus requires the camera
to be maneuvered into position with a distance to the
The present photographic system relates to underwa
ter camera enclosures, and more particularly, underwa
ter camera enclosures having an underwater sonar
range-?nding means to control the enclosed camera.
In underwater photography the requirements for the
physical structure of the camera housings are substan
tially different for that of cameras not used under the
water. Speci?cally, there is a requirement for the cam
era to be watertight and light transparent in the field of
underwater subject equal to predetermined focal
length, at which time the camera is triggered and the
photograph is taken. The apparatus disclosed in the
above-cited patents provide no means to communicate a
measured distance through the water to the subject, nor
means for providing a signal proportional to that dis
tance to the enclosed camera in a manner to adjust or
affect the focusing of that enclosed camera.
Additionally, there are differences in the optical
properties of the air and the water medium by which
underwater use. It is typical of the known underwater 20
the focus of the cameras calibrated in the air media must
camera enclosures to provide a transparent window
be adjusted or offset to provide correct focusing
through which the camera will photograph the desired
through the water media.
view of the camera. There are means known which
enclose an otherwise non-underwater type camera for
underwater subject, as well as multiple external me
chanical actuators to manipulate other controls of the
camera enclosed therein. Furthermore, transparent
openings in the underwater enclosures have been pro
vided to allow self-contained ?ash units positioned
The photographic system, according to the present
invention, includes an underwater camera enclosure
which determines the necessary camera-to-subject dis
upon the structure of the camera to illuminate the sur
tance signal and communicates that signal to the dis
rounding underwater area through the same enclosure
tance adjustment of a camera, including a self-develop
containing the camera. Of particular interest are the 30 ing camera, enclosed within the underwater housing to
enclosures for the recently developed self-developing
control the camera focus and other distance-related
cameras, wherein the film ejects from the camera upon
adjustments. The underwater camera enclosure pro
completion of the exposure and commences developing
vides the subject distance signal according to an under
by itself. An example of enclosures permitting underwa
water sonar range-finding system and simulated echo
ter use of self-developing cameras are shown in US. 35 computer wherein the subject distance signal provided
Pat. Nos. 3,832,720 and 3,832,725, for use with the Po
to the camera is related to the distance through the
laroid Model "BX-70” self-developing instant camera.
water medium, as well as certain fixed parameters such
These patents are also applicable to the subsequently
as the shape, optical refractive index and thickness of
developed Polaroid Model “Pronto” and “660.” Fur
the viewing port of the enclosure, location of the cam
ther advances in self-developing cameras include auto
era within the enclosure and difference in optical char
matic focusing according to signals provided by an
air-sonar range-?nding device contained within the
self-developing camera housing. These air-sonar fo
acteristics of air and water. The subject distance signal
is thereupon communicated to the camera within the
airtight underwater enclosure to thereby control the
cused cameras cannot be successfully used within the
focus and other distance-related adjustments. When the
camera housings disclosed in the above-cited patents 45 camera comprises an air-sonar type camera, this subject
due to the great differences in acoustic propagation
distance signal is communicated in the form of a simu
parameters of the media between the air-sonar trans
lated echo which is accepted by the camera, without
ducer and the subject to be photographed. Speci?cally,
alteration of the camera.
the air-sonar signal must pass through a short distance
Furthermore, the camera contained within the enclo
of air, a plexiglass or other rigid and clear enclosure
sure is typically of the self-developing type camera
material, the water through a distance to the subject,
having automatic ejection of the exposed cell within the
and back in a reverse sequence to the air-sonar element.
watertight enclosure, but may include other distance
The typical result is for the air-sonar signal to be sub
adjusting cameras, such as the Honeywell Visitronic,
stantially entirely re?ected within the camera’s water
Canon CAFS (Canon Auto Focus System), Canon SST
proof housing so as to cause the focusing mechanism of 55 (Solid State Triangulation) and Honeywell Visitronic
the self-developing cameras to focus at either the inner
TCL (Through Camera Lense) which are geometric
surface of the waterproo?ng housing or the maximal
focus means. The camera also includes, within its own
distance limit of the camera providing an improperly
structure, an automatic air-sonar focus control of a type
focused picture.
generally known and commercially available which
Adaptation of the underwater camera enclosure to 60 emits a sonar pulse when triggered. The underwater
include an acoustic window, such as described in US.
enclosure includes a transponder having an air-sonar
Pat. No. 2,960,175, to permit the air-sonar transducer to
communicate to the water media, will be unsuccessful
due to the great difference in sound propagation veloc
ity between the air and the water medium. The result of 65
receiver which is placed a negligible distance from the
air-sonar transducer on the camera. The transponder
receives a transmitted signal from the enclosed camera
in the form of an acoustic tone burst issued when the
this difference in propagation velocity, assuming the
camera is triggered and provides a triggered-camera
acoustic window permits suf?cient energy to traverse
the boundary of the media, would be to cause the cam
signal. In the transponder, the triggered-camera signal
initiates an underwater range ?nder which has a sonar
transmitter at a frequency appropriate for the water
medium and is transmitted by appropriate known hy
droacoustic transducers. The hydroacoustic transducer
propagates the sound energy through the water media
Referring now to the drawing, in particular FIG. 1,
and receives the re?ected underwater echo in a known
the underwater photographic system including cylindri
manner, providing a received underwater echo signal
proportional or related to the subject distance underwa
ter. The received underwater echo signal is detected by
cal housing 10 is shown according to one embodiment
of the present invention. Housed within the enclosure
an underwater sonar receiver also within the underwa
focusing control 12, represented here by the Polaroid
ter range ?nder which provides an'underwater-echo
camera Model “Pronto" sonar series. The underwater
trigger signal. The triggered-camera signal and the
underwater-echo trigger signal are received by a timing
enclosure 10 comprises two main sections, the front
section 14 providing a housing covering substantially all
circuit in an underwater range computer which deter
mines the underwater transit time and provides an un
apparatus described hereunder, and the back plate 16
derwater transit-time signal. The transit-time signal is
then scaled by a simulated-echo computer and pulse
generator, which relates the underwater transit-time
signal to the triggered-camera signal and proportions
the underwater transit-time signal according to the 20
acoustical and optical difference in air and water media,
as well as certain ?xed parameters including the geome~
try and optical refractive index of the viewing port of
the enclosure, the location of the camera within the
nclosure and the location of the hydroacoustic trans
ducer with respect to the enclosure, thereby creating a
simulated air-echo signal which simulates a return pulse
for a camera-to-subject distance in an air medium that is
10 is a self-developing camera with air-sonar automatic
of the components of the camera and the additional
which is ?xedly mounted by retaining screws 17 or
other suitable closure means to the front housing 14
forming a watertight enclosure. The back plate 16 fur
ther comprises shelf elements 70 and 72 for retaining the
electronics (contained in electronics compartment 48)
and the camera 12, respectively. The underwater enclo
sure 10, comprising the elements 14 and 16, provides a
watertight or ?rst medium environment in which elec
trical or mechanical devices, such as a conventional and
unmodi?ed camera, may operate therein. The back
plate will also provide the appropriate transparent aperi
tures positioned as necessary to utilize the focusing,
picture counter, view ?nder, low light level detector
and other viewing ports inherent in the body and design
appropriate to cause the camera to properly control its
of the camera 12. The front housing 14 will have at‘ least
focus and other distance-related adjustments for the
in-water subject. The simulated-echo signal is transmit
ted by a pulse transmitter which provides the appropri
ate signal needed to drive an air-transducer placed ap
propriately to communicate with the self-developing
camera’s air-sonar (range-?nding) transducer.
In addition to providing a simulated air-echo signal
relating the underwater distance to the subject to the
one optically transparent surface 18 providing a view
in g port for the camera 12; furthermore, it is desirable to
provide additional surface sections of the front enclo
sure 14 to be transparent to allow the operator of the
camera to view the exposed pictures as they are ejected
from the camera 12. This may be provided by allowing
the front surface 18 to be transparent over a sufficiently
large area to permit the above-described viewing or the
camera in terms of the related air transit time, the
entire housing 14 to be transparent.
above-described system may also include compensation
for the optical foreshortening due to the differences in
optical characteristics of air and water.
chanical and electrical through-connections which en
able the operator to operate and adjust or otherwise
permit external signal connections to communicate with
The underwater enclosure 10 includes various me
communicate with the enclosed camera, as well as to
The operation and advantages of the present inven 45 the camera therein. The camera trigger 22 is operated
tion will become more clear upon reading the following
detailed description of the invention in conjunction
with the accompanying drawings of which:
FIG. 1 is an isometric view of one embodiment of the
present invention having cylindrical housing with an
underwater range ?nder and arti?cial illumination
source external to the housing;
FIG. 2 is an isometric view of an alternate embodi
ment of the present invention having rectangular box
like housing with an artificial illumination source inter
nal to the housing and hydroacoustic transducer of the
underwater range ?nder external to the housing;
FIG. 3 is a cutaway drawing showing exposed ?lm
retaining assembly, clip and ejected ?lm holder;
FIG. 4 is a view of one embodiment of the present
invention incorporating electrooptical couplers to ex
ternal illumination source, electrooptical communicator
by a mechanical linkage 24 which extends in an angular
manner to form a lever to urge the trigger 22 into the
housing of the camera 12; the linkage 24 extends
through the front housing 14 to the external trigger
knob 26 when it is rotatably depressed to effect the
triggering of the camera. A watertight seal is provided
by the assembly 28 which comprises plastic, rubber or
metalic ?ttings which are machined and arranged in a
known manner and are commercially available. Addi
tional mechanical adjustments may be provided by simi
lar mechanical linkages or actuators known in the art or
commercially available for camera adjustments such as
the exposure trimming adjustment 30 of the camera 12.
The exposure trimming adjustment 30 causes the auto
matic shutter control of the camera 12 to be biased in a
manner to slightly over or underexpose the ?lm accord
ing to a rotational adjustment of the control 30. The
mechanical connection of this control is accomplished
by another housing through-connect comprising a shaft
to external range ?nder and externally mounted mag
netically-coupled camera activator; and
65 linkage 32 having an abrasive or tooth-like tip 34 to
FIG. 5 is a block diagram of one embodiment of the
engage the knob 30 having a knurled surface thereupon.
simulated echo and underwater ranging system of the
The shaft is then actuated by an in-and-out movement
present invention.
or axially displaced through another watertight assem
bly 28. The shaft 32 has an external knob 36 by which it
In addition, an external ?ash unit or other illumina
tion light may also be af?xed to the front housing 14 as
is operated.
The mechnical actuators may also comprise an exter
shown by mounting ?tting 56. The ?tting 56 retains a
nally mounted movable magnet controlling an inter
multi-axis adjustable arm 58 to position and retain a
nally (within the enclosure 10) mounted reed switch.
lamp housing 60. The arrangement and physical dimen
The reed switch in turn causes electrical actuation of
sions of the arm 58 and the lamp unit 60, as well as the
?tting 56, are arranged to provide both mechanical and
the camera 12 directly if equipped with a contact clo
electrical connection to the underwater enclosure 10.
sure trigger as the Polaroid Model “SK-70,” shown in
The ?tting 56 may also provide an electrical through
FIG. 4 or of a solenoid mechanically coupled to the
10 connect by which cable 62 mates with the camera re
trigger 22 of camera 12.
ceptacles 64A and 64B in the camera 12 via plugs 66A
The camera 12 is focused by an air-sonar range-find
and 66B, respectively. The electronic connection and
ing system, known to the art of automatic and self
operation of external illumination sources, such as ?ash
developing cameras, whereupon an acoustic signal of
units, including electronic ?ash or ?ash bulb types, are
ultrasonic frequency or ?rst medium acoustic pulse is
propagated through the air by the air-sonar transducer 15 generally known in the art and commercially available.
Alternatively, an electromagnetic coupler (for enclo
40 mounted within the enclosure of the camera 12 and
received upon echo from a distant target. The distance
to the subject is ?rst calculated from the time between
sures which contain a section of electromagnetically
transparent material such as plexiglass or stainless steel),
may include the primary of a transformer coil with
the transmission of the acoustic signal and the echo and
then applied to the camera controls to automatically 20 suitable resistance and shunted by a back biased diode,
is driven by the camera from receptacles 64A and 64B
adjust the camera for focus in a ?rst media, typically air,
to send electromagnetic energy through the wall of the
and exposure. The housing 14 includes, as part of its
underwater enclosure 10. This electromagnetic energy
structure or additional to it, an air-water transponder
is received by a transformer secondary coil or other
including a sound absorbing cup 42 positioned to sub
stantially entirely overlay the surface of the air-sonar 25 electromagnetically sensitive element which effects a
flow of current through the electromagnetically sensi
transducer 40. The absorbing cup 42 includes an inter
elements. The ?ow is then used to control subse
nal sound absorbing lining wherein the acoustic signal
quent external, electrically activated devices.
transmitted by air-sonar transducer 40 is suf?ciently
An alternate embodiment of the present invention is
shown in FIG. 2 wherein the underwater enclosure 10A
is constructed in a rectangular shape. The forward
housing section 14A surrounding the camera includes
an optically transparent front section 18A through
which the photographs are taken. The rear plate 16A
fastens to the forward housing section 14A by screws or
other suitable devices forming a watertight enclosure.
In this embodiment of the present invention, the rear
absorbed to inhibit detection of an echo (within the
absorbing cup 42) by the air-sonar range-?nding system.
Also included in the absorbing cup 42 are two transduc
ers 44A and 44B whereupon the acoustic signal air
sonar pulse transmitted through air by the air-sonar
transducer 40 is received by transducer 44A and there
upon converted to an air-sonar transmission pulse elec
trical signal. The transducer 44B converts a simulated
air-echo electrical-pulse signal into a simulated-echo
signal to be received by air-sonar transducer 40. The
plate 16A further comprises shelf elements 70A and
72A for retaining the electronics (contained in enclo
transducers 44A and 44B are connected to electronics
sures 48 and 50 of FIG. 1) and the camera 2, respec
tively. In addition, the internal shelf element 70A con
compartment 48 by leads 46A and 468, respectively,
where they communicate with an internally contained
tains an extension arm 74 which extends forward above
and out of the ?eld of view of the camera to retain
air-sonar receiver and simulated-echo transmitter, re
spectively. Additionally contained within electronics
flashlamp assembly 76 which, in normal hand-held op
compartment 48 are an underwater range computer and 45 eration, resides on the top of the camera 12 at socket
a simulated-echo computer and generator, discussed in
connection 64A. The electrical connections between
FIG. 5, below. The electronics contained within hous
the flashlamp set 76 and the socket 64A are provided by
ing 48 communicate to an external enclosure 50
the electrical wiring harness 78 having socket 80 avail
mounted on and external to the front housing 14. The
able to receive the ?ashlamp set 76, as well as plug 82 to
external underwater sonar housing 50 includes an un 50 be inserted into the socket 64A of the camera 12. The
derwater sonar range-?nding system, described below
to operate in a second medium, typically water, which
communicates to the internal electronics housed in elec
tronics compartment 48 by a wire lead 52 plugged into
flashlamp set 76 is mounted forward within the enclo
sure 14A against the front section 18A to minimize
internal light re?ection from the flashlamp set 76 to the
camera 12 from the internal surface of from section
compartment 48, provided through the mechanical
18A. Furthermore, the mechanical linkages 24 and 32
support 54A which, with support 548, af?x the sonar
housing 50 to the front housing 14. The underwater
sonar housing 50 also comprises hydroacoustic trans
ducer 55 through which the underwater sonar signal is
generated and propagated. This hydroacoustic trans
ducer may be formed of appropriate dimensions and
acoustic material as known in the art. The dimensions
and nature of the hydroacoustic trandsucer will be such
with the associated hardware 28 are also present in this
embodiment as were in the prior embodiment of FIG. 1.
The backplate 16A of FIG. 2, as well as 16 of FIG. 1,
also provide the appropriate transparent apertures posi
tioned as necessary to utilize the focusing, picture
counter, view ?nder, low light level detector, and other
viewing ports inherent in the body and design of the
camera 12.
to provide the desired directional characteristics of the
A sound absorbing cup 42A resides directly in front
range-?nding system contained therein to permit a se 65 of the camera 12 air-sonar transducer 40 by clamp
lective distance determination according to the direc
means to fasten the cup 42A directly to the housing of
tion the camera housing and thus, the sonar system, is
the camera 2, or by means which af?x or position the
cup 42A in the forward housing section 14A so as to
absorb substantially all of the transmitted energy from
the air-sonar transducer 40 when the camera 12 is posi
tioned within the enclosure 10A. Contained within the
restricts the ejected ?lm 138 from movement which
would obstruct the view of the camera; furthermore,
the tray 130 is transparent to allow the camera operator
cup 42A are transducers 44A and 4413 in the same man
to inspect the prior ejected ?lm. The tray 1311 includes
ner described in reference to FIG. 1. The leads 46A and
46B connect the transducers 44A and 44B to the elec
a shade retainer 137 in the form of a pin running
through the center of the curl of the shade 131 (part of
tronic enclosures contained and supported upon the
shelf element 70A. The enclosure 84 includes the cir
shade 131 so as to facilitate ejection of the ?lm. This
the “Pronto” camera) to partially extend the ?lm light
cuitry relating to the air-sonar transducer 40 of the
?lm light shade 131 is also shown partially extended in
camera 12. This includes the electronics associated with
the air-sonar receiver and the simulated-echo transmit
FIG. 1, and not shown in FIG. 2 to show the position of
ter. The electronics therein receive the (?rst medium)
acoustic signal air-sonar pulse transmitted from the
camera 12 transducer 40 after receipt by transducer 44A
mounted on the tray 130 urges the clip 132 into the
elements 132, 140. In FIG. 3, triangular clip retainer 140
opening 133 against the spring 136 when the tray 130 is
properly seated against the camera 12.
An underwater enclosure 108 for the Polaroid Model
and condition it through use of the air-sonar receiver so
as to produce a triggered-camera signal or initiate sig
nal, which is provided both to the electronics of the
housing 14B and rear plate 168 are joined by removable
underwater (second medium) sonar range-?nding sys
screws 173 or other closure devices to provide a water
“SX-70” sonar camera 13 is shown in FIG. 4. The front
tight seal. In operation, the camera 13 partially ejects
contained in enclosure 88, and to the electronics of the 20 exposed ?lm 138 to be retained by the camera 13 by
bottom clip 142. Clip wedge 144 inserted between the
underwater range computer and the simulated-echo
tem, including the sonar transmitter and sonar receiver
computer and generator contained in enclosure 86. The
electronics within enclosure 84 also provide a simulated
air-echo electrical pulse to energize the return trans
ducer 44B so as to produce a simulated air-echo signal 25
for receipt by the camera’s air-sonar transducer 40A.
The simulated air-echo electrical pulse is triggered by
the electronics contained within enclosure 86 including
retaining action of the bottom clip, allowing exposed
?lm 138 to be fully ejected from the camera 13 into a
transparent ?lm tray 130A supported near the transpar
ent front 18B by support 152. The camera 13 is sup
ported from the rear plate 16B by camera bracket 146
and retaining screw 148. The camera bracket is attached
to rear plate 16B by screw 150, and also supports clip
the underwater range computer and the simulated echo
computer and generator which are controlled by an
wedge 144 and transparent film tray 130A. External
?ash socket 64C retains a light pulse-producing element
162, which includes a light emitting diode (LED). The
underwater echo trigger signal generated within enclo
sure 88 in response to the received echo. The electron
ics within enclosure 88 through lead 92 initiate an elec
light pulse thereby produced by element 162 passes
through the housing 14B, being at least partially trans
parent, and is received by photosensitive element 164
trical sonar output signal of appropriate frequency and
duration for underwater propagation from hydroacous
tic transducer 90 mounted externally on the enclosure
10A so as to communicate directly with the surround
ing water medium. The frequency to be used for under
water propagation is several times greater than the air
propagation frequency for a speci?ed transducer cross 40
section and directional sensitivity pattern, according to
the relative differences in acoustic propagation veloci
ties in water and air, respectively. The hydroacoustic
camera 13 body and the bottom clip 142 defeats the
enclosed in light-proof cover 166, to control a flow of
current on attached lead 178 to contact an external light
source (not shown). A cover 428 encloses acoustic
transducers to communicate with the camera 13 air
sonar transducer (not shown) and communicate signals
along leads 46A and 468, corresponding to the trig
gered camera signal and the simulated air-echo signal
discussed earlier. These leads are connected to electron
ics compartment 48A attached to the rear plate 16B.
transducer 90 may also include appropriate focusing or
coupling elements as necessary to provide ef?cient and 45 The electronics compartment 48A includes the simulat
ed-echo computer and generator as discussed in relation
determined behavior of the sound ?eld in the water
to compartment 48 shown in FIG. 1. The necessary
medium as known in the art. The lead 92, which plugs
control signals are passed through the housing 148 by
into enclosure 88, also provides a return path for the
electrooptical devices similar to those discussed in rela
received echo signal or second medium echo signal
produced by the hydroacoustic transducer 90 in re 50 tion to the communication of the external light source
control above. The triggered camera signal is passed by
sponse to an underwater acoustic echo which in turn
lead 52A to LED 168, which emits an optical signal
produces an underwater echo-trigger signal controlling
through the housing 14B to a corresponding photocell
computer and timing circuits producing an underwater
172, which controls a current on lead 180A, extending
transit time signal within enclosure 86. The circuits of
to the underwater range-?nding system producing an
the invention are powered by self-contained batteries
underwater-echo trigger signal which is communicated
within the ?lm of the camera 12 or by isolated battery
sources mounted in the enclosure 94 or external to the
to the camera 13. The signal is received by a LED 174
housing 10A altogether. Further detailed descriptions
over lead 180B to produce an optical signal through the
of the construction and performance of the electronic
housing 148 and is received by photocell 170, which
systems are described below.
Shown in FIG. 3 is a cross-section of the camera 12 at
controls a current over lead 523 to electronics compart
the opening, wherein ?lm retaining spring 136 normally
retain the ejected ?lm 138 for subsequent removal by
the camera operator. The ?lm ejected from the camera
12 through rollers 135 is freely released by the addition
of a clamp 132 which engages the ?lm ejection opening
ment 48A. The simulated echo computer and generator
contained therein produces a simulated echo electrical
pulse signal, as discussed above, which is communicated
to camera 13 over lead 468 to a transducer contained
65 within cover 428. Power supplies for electronics en
closed are provided by known energy sources, such as
133 of the camera 12. The ?lm then leaves the camera
batteries, also enclosed therein. The Polaroid Model
and is retained by a clear transparent tray 130 which
“SX-70” sonar camera is triggered by a contact closure
The normally open reed switch (nonconductive) is
underwater~echo trigger signal at lead 112 upon the
occurrence of the echo received by hydroacoustic
transducer 90. The signals on lead 104 from the air
closed when in a magnetic ?eld such as generated by a
sonar receiver as well as the signals on lead 112 from the
magnet 160, typically moved external to the housing
underwater sonar receiver are processed by the timing
circuit in the underwater range computer 114 to pro
duce an underwater transit time signal according to the
provided by an internal reed switch 158 which is con
nected to external trigger connector 154 by leads 156.
The block diagram of FIG. 5 shows the electronic
functions performed by the transponder, or underwater
camera enclosure according to the present invention in
relation to the instant camera 12. The cup 42 and 42A of
FIGS. 1 and 2, respectively, is shown schematically in
FIG. 5 as 42C wherein the transducers 44A and 44B are
(underwater transit) time between the triggered camera
signal or initial signal and the underwater-echo trigger
signal. The underwater transit time signal ATw or sec
ond medium transit time signal appears on lead 116
which is referenced to the timing of the triggered cam
era on lead 104 by the simulated-echo computer and
housed. The positioning of the transducers 44A and 44B
generator 118. The simulated-echo computer and gen
are to be substantially in line with the camera's air-sonar
transducer 40 and 40A of FIGS. 1, 2 and 4, shown here 15 erator 118 includes a time scaler which now produce a
as 40B, so as to ef?ciently couple the energy between
simulated air-echo electrical-pulse output signal accord
the elements 40 and 44A and 44B. While the spacing
between the elements is not critical, it should be mini
ing to the relationship of the signal A'I‘w as scaled by a
constant K, plus another time offset constant C. The
constant K adjusts the circuit to include the effect of
mized. In addition, when electrically feasible according
to known techniques allowing the same transducer to 20 differing values of acoustic propagation velocity for the
water and air mediums, in particular, the fact that the
both transmit and receive, the elements 44A and 448
acoustic propagation velocity for water is approxi
may be a single transducer. Alternately, transducers for
mately ?ve times the acoustic propagation velocity for
a different energy propagation media, such as electro
air, and includes the effect of perceived optical differ
static and electromagnetic transducers, are useful in
providing signals where signals in the primary (acous 25 ences due to the different optical characteristics of the
air and water media, in particular, the foreshortening
tic) media cannot be adequately received or transmit
caused by the water medium, further described below.
ted. The transducers 44A and 44B are connected to the
The constant C takes into account other factors such as
air-sonar receiver 102 and simulated-echo transmitter
those relating to camera location within the enclosure,
circuits 122 described below by conductive paths 46A
and 46B, respectively. The transducer element 44A 30 the geometry and optical refractive index of the view
behaves as a microphone to receive the air-sonar acous
ing port of the enclosure, and the location of the hy
tic signal propagated from the transducer 403 and to
convert that signal to air-sonar transmission pulse elec
trical signal in turn received by air-sonar receiver 102.
The air-sonar receiver 102 ?lters the signal received to 35
droacoustic transducer, with respect to the enclosure.
The simulated-echo computer and generator 118 pro
duce a trigger output along lead 120 which controls the
simulated-echo transmitter 122, which includes a pulse
generator and an ampli?er to create a signal along lead
46B, connected to the transducer 448. The transducer
44B produces a simulated-echo acoustic signal coupled
eliminate spurious information, detects the leading edge
of the desired signal and produces a triggered camera
signal at the occurrence of that leading edge. The trig
to the sonar camera transducer 40B in a manner to
gered camera signal is communicated to an underwater
sonar transmitter 106 by lead 104 to control the under 40 emulate acoustic signals found in the automatic focusing
of the self-developing camera on the subject at the ap
water sonar transmitter 106 according to the triggered
propriate distance under free air conditions. The ele
camera signal. The underwater sonar transmitter 106
ments and components of the electronic subsystems are
provides an electrical sonar output signal along lead 108
generally known in the art and may be produced by
to the hydroacoustic transducer 90 as shown and posi
tioned in the previous FIGS. 1 and 2. The hydroacous 45 those skilled in the art or otherwise obtained commer
tic transducer 90 includes the necessary acoustical
In the simulated-echo computer and generator 118,
transmission material to couple and propagate the un
the relationship formed relating the underwater trans
derwater sonar pulse energy into the water medium and
mission time (between the sonar transducer and a sub
produces an underwater acoustic signal according to
the electrical sonar output signal from the sonar trans 50 ject) to the air transmission time of the acoustic signal
mitter 106. The underwater acoustic signal proceeds
for the same distance (between the sonar transducer and
the subject), is accomplished by a constant K. The con
through the water medium to any particular acoustic
discontinuity in the medium whereupon a re?ected
stant K relates the ratio of in velocity of transmission of
underwater acoustic signal is produced. The reflection
acoustic energy through the water medium (V w) rela
then propagates back and is received by the hydroa 55 tive to the air medium (Va), which is approximately
coustic transducer 90 which now produces a received
?ve; also included in the constant K is a similar ratio A
electrical echo signal along the same lead 108 which is
relating the optical distance offset due to the different
optical properties of the air and water media. For our
purposes here, the optical differences cause the subject
now further connected to an underwater sonar receiver
110. The underwater sonar receiver 110 includes a ?lter
circuit to remove unwanted signal components and an
automatic gain control (AGC) circuit. The AGC circuit
blanks or clamps the signal received during the burst of
to appear at a closer distance to the camera than they
actually are. For instance, when the camera is negligible
distance from port, a subject at an underwater distance
of four feet will properly be focused when the camera is
energy from the transmitter and provides a time-related
adjused to a distance of approximately three feet with a
gain control wherein the more distant or weaker signals
(which generally occur later in time after the initial 65 planar viewing surface 18, 18A or 1813 on the front
sonar pulses) are increased in amplitude over time. The
housings, so A equals 0.75. A further compensation to
provide a simulated echo is accomplished by constant C
underwater sonar receiver 110 further includes a signal
to adjust the echo response for the distance between the
detector circuit and a trigger circuit to produce an
lens of the camera 12 and the optical viewing surface 18,
defeat said retaining assembly, thereby allowing said
18A or 18B of the camera enclosure, and the location of
the hydroacoustic transducer 90 relative to the camera
self-developing camera to fully ‘eject said exposed ?lm
from the body of the self-developing camera.
5. The apparatus of claim 4 wherein said retaining
enclosure. Assuming that the hydroacoustic transducer
90 is mounted on the enclosure at the same distance
from the camera as is the viewing surface 18, 18A or
assembly further includes a retractable ?lm shade, said
clip further comprises a shade retainer to inhibit the
1813, the simulated air-echo signal Ats generally de
retraction of said ?lm shade.
scribed above has the following more speci?c relation
6. The apparatus of claim 4 further including a film
ship between the underwater transit time Atw and the
camera-to-transducer (and viewing port) distance, Dc: 0 holder to retain said exposed ?lm after ejection from
said self-developing camera.
7. A system enabling the underwater utilization of an
apparatus having an air distance measuring device nor
when the location of the transducer 90 and the viewing
mally operable to measure a distance to a subject in air
port relative to each other changes, the second (right
and providing an initiate signal, said system comprising:
most) term becomes more complex. Also, for more
a watertight enclosure retaining said air distance mea
accurate translation between media, which may include
suring device;
different media, temperature effects, and differing opti
an underwater ranging means receiving said initiate
cal port geometries and optical refractive indexes, the
values of A, K, Va and Vw will necessarily change or
become more complex.
signal transmitting an underwater acoustic signal
The implemetation of the above-described relation
ships and the enclosure and underwater range?nder
system is intended to include known analog and digital
signal for transmitting a detected echo signal to
said air distance measuring device to provide a
range signal therein corresponding to the distance
The self-developing camera enclosed in the above
description of the present invention is not limited to the
Polaroid “Pronto," “SK-70" and “660" series, and the
scope of the embodiment may be expanded to include
other automatic range-?nding or focusing cameras,
incorporating appropriate transducer devices to com
underwater between said apparatus and said under
water subject.
8. A system enabling the underwater utilization of an
apparatus having an air distance measuring device nor
mally operable to measure a distance to a subject in air
and providing an air-sonar acoustic signal, said system
municate with the particular range-?nding system of
the enclosed camera. Furthermore, the above descrip
tion of the present invention is made by way of example
only and is not intended to limit the present invention.
Other embodiments and modi?cations made by those
skilled in the art are entirely within the scope of the
present invention which is not limited accept by the
a watertight enclosure retaining said air distance mea
suring device;
an underwater ranging means receiving said air-sonar
acoustic signal transmitting an underwater acoustic
signal and receiving an underwater echo signal
following claims.
from an underwater subject; and
means responsive to said received underwater echo
What is claimed is:
l. Photographic apparatus adapted for underwater
signal for transmitting a simulated echo signal to
said air distance measuring device to provide a
range signal therein corresponding to the distance
underwater between said apparatus and said under
water subject.
9. The system of claim 8 wherein said underwater
photography with an air-sonar range-?nding camera
utilizing an air-sonar acoustic signal, comprising:
a watertight enclosure retaining said camera;
an underwater sonar range-?nding means responsive
to said air-sonar acoustic signal for transmitting an
underwater sonar signal and for receiving an un
derwater sonar echo signal from an underwater
ranging means comprises a sonar ranging means.
10. The system of claim 9 wherein said means respon
subject to be photographed; and
sive further includes at least one of an acoustic means,
means resonsive to said received underwater sonar
and electro-optical means, and an electromagnetic
echo signal for transmitting a simulated echo signal
means to communicate.
to said air-sonar range-?nding camera to produce a
11. The system of claim 10 further including at least
one of a trigger means for activating said apparatus and
range signal therein corresponding to the distance
between said camera and said underwater subject.
an illumination control means for synchronizing exter
nal illumination to said apparatus.
2. The apparatus of claim 1 wherein said means re
sponsive further includes at least one of an electro
acoustic means, an electro-optic means, and an electro
12. The system of claim 11 wherein said trigger
magnetic means to communicate said distance signal to
said unmodi?ed camera.
3. The apparatus of claim 2 said camera further com
prising a trigger means and an illumination means hav 60
ing a trigger signal and an illumination signal, respec
bly, said underwater enclosure further comprises a clip
partially inserted into said self-developing camera to
means includes a reed switch and a magnetic device,
and said illumination control includes a light source and
a photocell.
13. A transponder to operate distance controlled
apparatus designed for operation in a ?rst medium, in a
second medium and to provide a distance-related signal
to adjust said distance controlled apparatus according
4. The apparatus of claim 1 wherein said camera
said self-developing camera by a retaining spring assem
underwater subject; and
means responsive to said received underwater echo
circuitry and techniques.
comprises a self-developing camera providing partially
ejected exposed ?lm retained in part within the body of
and receiving an underwater echo signal from an
to a distance between said controlled apparatus and a
selected subject in said second medium, said transpon
der comprising:
a second medium range determining device including
a sonar device providing a ?rst signal relating a
distance between said transponder and said se
mit said simulated air-echo signal formed in response to
lected subject;
said simulated air-echo electrical signal.
16. The transponder of claim 15 wherein said time
scaler further relates the differences in optical refractive
a conversion means to relate said ?rst signal to said
distance controlled apparatus as a converted dis
index in the ?rst medium and the second medium,
wherein said ?rst medium re?ected signal is adjusted to
properly focus for distance for said selected subject.
17. The transponder of claim 16 wherein said time
scaler further adjusts the second medium delay signal
tance signal,
wherein said second medium sonar device receives an
initiate signal in response to said distance con
trolled apparatus and produces said ?rst signal
thereafter, said conversion means further compris
10 according to at least one of the ?xed parameters of an
optical viewing port including the shape, thickness, and
a timing circuit to measure the elapsed time between
said initiate signal and said ?rst signal to produce a
optical refractive index, and distance between said
second medium delay signal; and
means to communicate and said camera.
18. The transponder of claim 17 wherein said air
a time scaler to adjust the second medium delay sig
nal according to a differing rate of propagation of
an acoustic signal through the ?rst medium and the
propagation of an acoustic signal through said sec
ond medium producing a simulated air-echo elec
sonar transmitter and said air sonar receiver includes a
common transducer.
19. The transponder of claim 18 wherein said ?rst
medium is air and said second medium is water.
20. The transponder of claim 19 wherein said second
trical signal.
14. The transponder of claim 13 wherein said distance 20 medium sonar device futher includes:
a sonar transmitter responsive to said initiate signal to
controlled apparatus comprises a camera having a shut
ter release and a distance adjustment comprising at least
one of a focus control, an aperture control and a shutter
time control, said conversion means further comprising
means to communicate to said camera said converted 25
distance signal.
15. The transponder of claim 14 wherein said camera
further comprises an air-sonar range?nder producing a
?rst medium acoustic signal and receiving a simulated
air-echo signal in said ?rst medium, said means to com 30
municate further comprising an air-sonar receiver to
receive said ?rst medium acoustic signal to form said
produce an electrical sonar output signal;
a hydroacoustic transducer responsive to said electri
cal sonar output signal producing an underwater
acoustic signal and receiving a re?ected underwa
ter acoustic signal producing a received electrical
echo signal; and
a sonar receiver responsive to said received electrical
echo signal to produce said underwater echo trig
ger signal, said hydroacoustic receiver including a
signal ?lter, an automatic gain control circuit and a
pulse detector circuit.
initiate signal; and a simulated echo transmitter to trans
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