Quantitative Photography: The Fragmentationof a Science~

JEAN ST. THOMAS, Phologrammelry, Inc.Silver Spring , Md.

ABSTRACT: In the face of the assertion that photogrammetry is quantitative photogra­phy in all its phases, the latter is widely used as a scientific tool by practitionerswho are oblivious of photogrammetry, or who reject identification with photogram­metry, or who, from necessity, have by-passed and are found beyond the limiteddisciplines which constitute classical photogrammetric practice.

Despite the all-encompassing meaning attributed to the term "photogram­metry," a growing number of designers, experimenters and routine users of photo­graphic instruments forge ahead in science and industry, using new methods of dataderivation which go unreported in the photogrammetric literature. The vital functionwhich quantitative photography plays everywhere is of a magnitude such that thequestion poses itself as to which is really a "special application" of the other.

No data are available that would serve to express the relative number of the usersof photographic instrumentation in science generally, versus that used in photo­surveying. However, with the aid of a series of clues, an attempt is made to showthat current definitions are false, and that major contradictions exist which hamperthe dissemination of knowledge relative to metrical photography as a whole. Thus,methods used in one field are denied to workers in other fields for lack of communica­tion.

Recognition of the photo-instrument as the common denominator of all practi­tioners of metrical photography, and adoption of a standardized terminology basedon instrumentation types, are advocated to achieve a break-through across the wallsof knowledge compartmentation and to strengthen the field through a unifyingcodification.

PERSPECTIVE

T HE field of quantitative photographyis vast. No scientific research or in­

dustrial endeavor can do without it. Al­though its function is the determinationof the values under study, there is ironyin that its own magnitude should not beaccurately measurable. But its relativemagnitude can be simply conveyed: pho­togrammetry, itself the source of a con­siderable literature, represents a com­paratively small and highly specializedarea in this great domain. The first inklingthat photogrammetry might not be quan­titative photography in all its phases isfound in the following two definitions:

Definition 1. Photogrammetry is "thescience or art of obtaining reliablemeasurements by means of photog­raphy." (Definition by the founders ofthe ASP.)

Definition 2. Photogrammetry is theart and science of deriving surveys

from aerial photographs. (Webster sUnabridged.)

Each of these definitions is given by asource authoritative enough to challengeany questioning, were it not for the ob­vious contradiction. One such authoritytherefore must lack infallibility; and sincequantitative photography is under dis­cussion, it is pertinent that the record beexamined for clues that would cancel oneof the definitions.

CIRCUMSTANTIAL EVIDENCE

In the following, a number of clues ispresented, each clue pertaining to somephase having direct or indirect bearing onthe question of the synonymity of theterms "quantitative (or metrical) photog­raphy" and "photogrammetry." Withthis in view, the sanctification given tomeaning by common usage and by sus­tained omission cannot be ignored, andde facto acceptance seems indicated in

* The approval given by the Publications Committee to the publication of this paper is not tobe considered as meaning an endorsement or approval of the contents of the paper by that Com­mittee, the Society or Photogrammetry, Inc.-Editor.

467

468 PHOTOGRAMMETRIC ENGINEERING

such cases where typical irreversibility oftrend of meaning is involved.

1. The term photogrammetry as an en­compassing concept is nullified by theuse by respected authorities of one ofthe qualifying "non-topographic"(photogrammetry) whenever topog­raphy is not involved.

2. Major works, as well as most anytextbook or journal on photogram­metry, are engrossed with surveyingand cartographic problems to an ex­tent so nearly exclusive that other ap­plications are treated by implicationas (a) curios, or (b) as "special appli­cations." Finsterwalder1 devotes fourlines to special applications and nineand one half lines to scientific appli­cations. Even if both are lumped, thisrepresents at best a mention "enpassant."Zeller's authoritative text2 acknowl­edges a somewhat greater recognitionof "special applications" 10 pages outof 304, or three per cen t.

3. Lacmann3 found that support couldnot be had (even from photogram­metric institutions) for the compila­tion of knowledge pertaining to "non­topographic" instru mentation and pro­cedures. He publishes this knowledgehimself for fear that the information itrepresents would otherwise be lost.

4. Fink4 publishes a well-regarded bookon methods of quantitative photog­raphy bearing a title which avoids theuse of "photogrammetry," "non-topo"or "special." Calling a spade a spade,he uses "Photographische Messtech­nik."* Although he touches on the artof deriving maps from aerial photog­raphy, he realistically treats it as aspecial application of quantitativephotography.

5. Vast research projects in this country(and perhaps also abroad) many ofthem security classified, rely, to anextent that cannot be overestimated,on the data produced by photographicinstrumentation. If quantitative pho­tography were removed, some of theseprojects would lose meaning. Yet,photogrammetrists are conspicuous bytheir absence in many of such research

* "Technik" is to be translated as "technol­ogy" rather than "technique," hence Photo­gr:Lphic Mensuration Technology.

centers. The photo-instrumentationused is conceived, designed, and builtunder the direction of photographicengineers and scientists who evolvedata compilation and reduction meth­ods that may completely by-pass thefield of classical photogrammetry.

6. Beyond the purely mechanical ad­vances, electronification of photo­graphic instrumentation and datareduction has greatly advanced oflate. While such instrumentation mayor may not be airborne, most of it isnot, it represents tremendous tech­nical advances, as do the systems ofdata reduction that go hand in handwith such instrumentation. Theseadvances steadfastly remain unre­ported by Commission V, of the In­ternational Society, that specializes inreports on "special applications."

7. There appears to be a considerableamount of confusion among photo­grammetrists as to what should beviewed as a "non-topographic" appli­cation. For example, work involvingstudies of tooth decay has been termednon-topographic.' Yet, what is in­volved is the determination of enamele~osion, in other words, surface analy­HS. But topography is the study ofsurfaces, irrespective of their location,on a tooth or on a mountain. Herethen is the multiple contradictioncaused by gnarled terminology:

Premise (a): photogrammetry is thescience of (all) photographic men­suration;

Premise (b): it is not so, and "non­topo" must be singled out;

Premise (c): topography is the anal­ysis of surface;

Premise (d): the study of a (tooth)surface is non-topographic.

8. Significant achievements in the designand applications of photo-instrumentsfor the location of events in time andof objects prope,lIed in space, and thedetermination of quantitative valuesregarding both, are the subject of totaland consistent silence in the photo­grammetric literature. Quantitativechronophotography rests more square­lyon instrumentation developed forthe purpose-often of superbly in­genious concept-rather than on"souped up" motion picture cameras,

QUANTITATIVE PHOTOGRAPHY: THE FRAGMENTATION OF A SCIENCE 469

as the few classical texts in existenceor those instances which the reports ofCommission V of the InternationalSociety of Photogrammetry would in­dicate.

9. Photo topography-the term given as asynonym of photogrammetry by Web­ster's dictionary-is by etymologicaldefinition and practice a two-dimen­sional pursuit. The addition of a singledirection of application not related tomapping, perhaps in the form of thephotographic determination of volume,has seen the relegation of problemsdevolving therefrom as a "special ap­plication." When it becomes necessaryto locate events III time, the four­dimensional curtain thus caused dropslike a pall-barring knowledge ofmetrical chronophotography from dis­semination.

10. The above effect can be reasoned thus:As a two-, or at best, three-dimensionalcreature, the phototopographer is tiedto trigonometry. His geometry IS

cartesian. His mathematical disciplinesuffices for the static problems of lo­cating points on a surface, to rectifyperspective distortion due to instru­ment tilt, and-in the pinch of a"special application"-to calculate thevolume of a coal pile, or the configura­tion of a sculptured bust from thephotograph of a man. The elements oftime and velocity, however, require theanalysis of a complex interaction offactors of differential nature. Trig­onometry, the classical backbone ofstatic photogrammetry, is impotent inthe face of non-uniformly distributedconstants, which demand a higherorder of differential equations. Trig­onometry thus falls short of the re­quirement of seeking parameters in afour-dimensional space-time con tin­uum. It is therefore only too naturalthat the evolution of metrical chrono­photography should have been in thehands of ballistics, dynamics andkinetics engineers whose geometry isrelativistic. They do not view them­selves as photogrammetrists. Nor dothey need to make special studies tomanipulate such triangulation prob­lems as they may face.

11. Failure to report the far-flung achieve­ments and the data relating to metricalchronophotography (except for lone

instances) now places photogram­metry in the following position:(a) photogrammetry IS (all) photo­

graphic measurement;(b) it is not so because "non-topo" is

"special";(c) even though photogrammetry IS

(all) photo-measuremen t, the in­jection of an added dimensionrenders it impotent, since "trig"cannot cope with non-cartesianproblems;

(d) or, "high speed photography" isreally "movie" work, removedfrom Hollywood only by camerarpm, and therefore irrelevan t tothe field.

12. Elsewhere, it appears that the ques­tion can be raised as to whether photo­grammetry is exclusively concernedwith objective quantitative ends, orwhether it should be understood alsoto encompass photo-interpretation, ahighly subjective hunting ground.This instance is one that will readily berecognized by photogrammetristswhilst perusing the late literature,laden out of all proportion with paperson photo-interpretation, a trend which

,is on the increase. We are now placedin a position to learn and to deducethat:(a) photogrammetry is all of photo­

graphic mensuration;(b) it is not so, because there are, in

addition to mapping, the non­topographic activi ties;

(c) by editorial implication photo­grammetry is not concerned withmeasurement only, but with sub­jective interpretation and thethereby engendered differences ofemotional approach.

13. Engineers active in the photo-instru­mentation field as designers or ex­perimenters, and with some of themin charge of vast operations, and whoare educated as to the practical mean­ing, to them, of photogrammetryandits literature, shun affiliation withphotogrammetric groups, because ofthe latters' hypnotic engrossment witha photo topographic navel, to thealmost nearly total neglect of theremainder of the anatomy of quanti­tative photography.

14. From the literature treating with

470 PHOTOGRAMMETRIC ENGINEERING

photographic instrumentation andover a period of time, it can begathered that not only is there awealth of knowledge that never showsup in photogrammetric journals, butthat metrical photographic practicehas pushed ahead and has by-passedclassical topo-photogram metric pro­cedures. Photographic data produc­tion and data reduction systems (somehighly mechanized) are being evolvedin a steady stream by professionalswho may never have seen a photo­grammetric journal, or have as yet toattend a meeting of photogrammetricgroups. That this is so, can usuallyonly be stumbled upon by personalexperience, in the absence of a Galluppoll or of writings on the subject.

15. A large number of specialists, activein quantitative photography on aprofessional level, are members ofgroups, which in varying extent dis­seminate knowledge relative to thefield, although dedication to the fieldas such may, or may not be expressed:The High Speed Photography Com­mittee of the Society of Motion Pic­ture and Television Engineers; theBiological Photographers Association;the Instrument Society of America;the Technical Division of the Photo­graphic Society of America; the So­ciety of Non-destructive Testing; theSociety of Photographic Engineers,and of late, the Society of Photo­graphic Instrumentation Engineers,which it was deemed necessary tocreate.

16. Elsewhere, the field of metrical chrono­photography is subject to the samenon-crystallization of purpose whichafflicts the users of euclidean photo­instruments: No delineation is madebetween quantitative and qualitative,between the objective and the subjec­tive approach, between the instru­men t and the camera, between theevent-mensurator and the event-be­holder, in short between the chrono­grammetrist and the chrono-photo­interpreter. It is the lack of this simplebut vital distinction that is responsiblefor the submersion of quantitativephotography into general photog­raphy, for the impotence of effectivesystematic search, for the organizeddissemination of relevant information.

17. Activities in the fields of non-chrono­photo-instrumentation, and of metri­cal chronophotography appear to besufficiently far-flung to warrant theassumption that phototopographersare rather outnumbered. This likeli­hood is enhanced by the circumstanceof the prevailing non-organization interms of the quantitative-photographicin terest, all while photogrammetry isknown to be well organized. However,the purpose here is not to count noses,but rather to show that the fragmen­tation of quantitative photographycould hardly be more complete.

Note: Since it appears from a goodpart of the foregoing that Webster'sdefinition of "photogrammetry" is themore realistic, reference to the termunder 17 above was made in the senseof that definition.

I t should also be noted that thenatural affinity of interest whichexists between the (non-metrical)"high-speed photographer" and thephoto-interpreter is not generally rec­ognized, and that a much greaterpurpose could be served if societyaffiliation-and the literature-weredivided along lines of interpretationvs. quantitative, rather than along theimaginary frontier created by theframe-rate of the instrumentationemployed.

UNRECOGNIZED COMMUNITY OF PURPOSE

While it is natural that specialists inany field should gravitate towards suchgroups as avowedly represent their ownchief interest, no useful purpose is served,if against all reason, such groupings at­tempt to function under hermetic sealfrom one another. The compartmentationthat exists in quantitative photographytoday could not remotely be ascribed towilful policy on the part of any group. Itis the thesis of this paper to find the cul­prit in the form of (a) twisted and other­wise inexistent terminology, and (b) lackof intent of purpose. If it were not so, asmall bridge, a thread however flimsywould have been spun to link all domainsof quantitative photography. There is nosuch link even among such major areasknown as "photographic instrumentation,""high speed" photography and "photo­grammetry." Overtures for some sort ofliaison, such as would be dictated by the

QUANTITATIVE PHOTOGRAPHY: THE FRAGMENTATION OF A SCIENCE 471

slightest recognition of affinity, have notbeen made.

Something is remiss in the house ofquantitative photography. Above all, andsince essentially mensuration is involved,there ought to be from the start a welldefined modulus, a clear cut declarationof purpose, a concise, well-outlined struc­ture. But the house of quantitative photog­raphy is no such organization. It is noteven definable as a house, but just as anumber of oddly assorted structures.Amongst these, a small, outwardly neat,but inwardly confused grouping standsout: topographic photogrammetry, rela­tively the best organized entity, althoughthe population of the other odd structuresfar outnumbers its own inhabitants.

I t is the object of modern city planningthat unintegrated and haphazard struc­tures be replaced with harmoniouslyinterdependent units, in systematic com­plementation for the benefit of all.

No planning, no integration of interest,no codification of the literature is possiblewithout the aid of a basic modulus in theform of a systematic nomenclature. Else­where, and in fields totally un plagued bylanguage defections, obstacles to thestorage of knowledge are the most seriousthreat to scientific progress seen by ourmost eminent scientists. The problembecomes one of staggering despair, whenthose designations are inexistent to beginwith, which should serve as the very founda­tion for such codification.

CONCLUSION

Before all else, a master key is needed,one that will proclaim and foster therecognition of the unity of quantitativephotography, the common purpose. Thatpurpose is to employ photography toobtain numerical data. No mensurationis possible in any field without the aid ofcalibrated devices, or instru men ts. Thephoto-instrument, then is the one de­nominator common to all who practicemetrical photography. No codificationpattern is thought poss'ible which does notuse as the point of departure this single,common tool, in forms as manifold asthere are directions of development orforms of application.

Outlines for codification have beenproposed elsewhere.6 •7 •8 It is not essentialthat the proposed patterns be accepted assuch, just as long as a similar, or better,

conven tion is adopted and pu t to practice.The Photographic Instrumentation Com­mittee of the Society of PhotographicEngineers is working on the problem. Con­tact will be made in time with othergroups interested in the furtherance ofquantitative photography, for purposes ofjoint action on the ultimate convention.

If the concept of metrical photography asan entity apart from all phases of sub­jective photography can be conveyed asbeing desirable, the concept of photo­graphic instrumentation as the commonhardware, the concept of photo-instru­metrics to denote the science, the conceptof photo-metrology as the body of knowl­edge useful to the creation of data and tothe reduction of data, the concept of thephotographic engineer as the designer ofinstrumentation, the concept of the pho­togrammetrist as the user of the instru­mentation in static geometric fields, theconcept of the chronogrammetrist as theuser seeking dynamic geometric param­eters-if these concepts can be forgedtogether to serve as the backbone of aharmonious nomenclature sanctionable byits very need, and acceptable for commonusage, only then will there exist a soundbasis for the orderly codification of quan­titative photography.

Search, now a nightmare of tediousness,will be greatly facilitated. Papers relevantto metrical photography will be concen­trated in a few journals devoted to thesubject in its full and true meaning ratherthan to narrow applications. It is thishyper-specialization which has causedmany a good manuscript to be channelledinto the general photographic literature,or into journals devoted to sympatheticbut hardly kindred interests. This special­ization in one single aspect of metricalphotography has also been responsiblefor blocking from dissemination valuableoriginal work by serious authors who thusfind themselves wanting of a logical vehiclefor the dissemination of their findings.

Technical societies, now deep in subjectmatter other than quantitative photog­raphy (while professing allegiance to thelatter) should establish a more realisticbalance between the avowedly mainpurpose of their existence, and narrowspecializations, and border interests ofremote sort. If this is not done, then thesurge for metrical photographic knowl­edge will create other foci of interest,

472 PHOTOGRAMMETRIC ENGINEERING

perhaps of better defined intent of purpose,but perhaps also agents for a still greaterfragmentation of the field. The presenceof a number of existing groups, which"dabble" in quantitative photography onthe side, contributes little to consolidation.

If clarification is ever to come to thismuddled situation, then photographicsocieties, their journals, as well as theindividual member, should stand up andbe counted: which do you serve? which areyour chief reasons for being? Subjectiveends: photography as a tool of opinion, ofemotional pursuits, of individual andhence controversial interpretation? Or doyou serve objective aims: photography asa precise yardstick for the appraisal ofour surrounding world; as a means tomeasure, and hence to master, the tran­sient event, the inexplicable phenomenon,the inaccessible point in space-or theunknown force which must be harnessed?

For such is the task of metrical photog­raphy. And however the belief may benourished that its scope is one of narrowspecialization, only its logical and thoroughorganization will reveal to us, in time, thefull magnitude of the sustained impactthat photographic instrumentation exer-

cises on the advancement of all humanknowledge.

REFERENCES

1. Finsterwalder, Dr. Richard, "Die Photo­grammetrie," Berlin, 1952. (Original edition1938.)

2. Zeller, M., "Lehrbuch der Photogram­metrie," Orell Fiissli, Zurich, 1947.

3. Lacmann, Otto, "Die Photogrammetrie inihrer Anwendung auf nichttopograph­ischen Gebieten," S. Hirzel, Leipzig, 1950.

4. Fink, L., "Die Photographische Messtech­nik," Oldenbourg, Munich, 1940.

5. Zeller, M., "Microphotogrammetrical Ex­amination of the Surfaces of Tooth-Fillings,"PHOTOGRAMMETRIC ENGINEERING, Vol. XI X,No.4, p. 660, Sept. 1953. (Symposium, Non­topographic Photogrammetry.)

6. Shaftan, Kenneth, "Photographic Instru­mentation and a Proposed System of Organ­ization," Photographic Engineering, 1952,Vol. 3, No.3, pp. 107-118.

7. St. Thomas, Jean, "Photographic Instru­mentation: A Proposed Terminology forCodification," Photographic Engineering,1955, Vol. 6, No.3, pp. 153-166.

8. Naslin, Pierre, "A Logical Classification ofHigh-Speed Motion Picture Cameras,"Proceed. Intern. Con., Royal Photo. Soc.,London, Sept. 1953.

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