United States Patent [191  4,381,144 Breslau  Apr. 26, 1983  UNDERWATER CAMERA ENCLOSURE  INCLUDING SONAR RANGE FINDING DEVICE  Inventor: References Cited U.S. PATENT DOCUMENTS 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 ABSTRACT  Gales Ferry, Conn. 06335  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 n"u "mI.ay, "9ml  Field of Search 03865;74 G/NwBar?53 61475/N39% "33mm B n/1“27.;/3 , 39.28. I 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 4,381,144 1 4,381,144 2 era to focus much closer than desired for a particular underwater subject distance. UNDERWATER CAMERA ENCLOSURE INCLUDING SONAR RANGE FINDING DEVICE 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 FIELD OF THE INVENTION 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. l0 BACKGROUND OF THE INVENTION 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 SUMMARY OF THE INVENTION 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 3 4,381,144 transmitter at a frequency appropriate for the water medium and is transmitted by appropriate known hy 4 DETAILED DESCRIPTION OF THE INVENTION 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 BRIEF DESCRIPTION OF THE DRAWING 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 5 4,381,144 bly 28. The shaft 32 has an external knob 36 by which it 6 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 tive 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 60 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 directed. cup 42A in the forward housing section 14A so as to 7 4,381,144 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 4,381,144 10 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. 148. 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 cially. 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 4,381,144 11 12 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 20 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 comprising: 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 tively. 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 65 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 13 4,381,144 14 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 mg: 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 35 45 50 55 65 i i i I!
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