The role of digital components in photogrammetric instrumentations

Bibliographic data

Monograph

Persistent identifier:: 830281363

Title:: The role of digital components in photogrammetric instrumentations

Sub title:: symposium of Torino, Italy ; 2nd - 4th October 1974

Scope:: ca. 200 Seiten in getrennter Zählung

Year of publication:: 1974

Place of publication:: Torino, Italy

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 830281363

Illustration:: Illustrationen, Diagramme

Signature of the source:: T 15 B 1280

Language:: English

Additional Notes:: Literaturangaben

Other Title:: Nebentitel: Digital components in photogrammetric devices

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Corporations:: International Society for Photogrammetry, Commission, 2

Adapter:: International Society for Photogrammetry, Commission, 2

Founder of work:: International Society for Photogrammetry, Commission, 2

Other corporate:: International Society for Photogrammetry, Commission, 2

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2015

Document type:: Monograph

Collection:: Earth sciences

Chapter

Title:: MODERN COORDINATE REGISTRATION SYSTEMS FOR PHOTOGRAMMETRIC INSTRUMENTS USED IN THE SOVIET UNION [Modern digital coordinate recorders for photogrammetric plotters]. G. A. Zotov, A. M. Zhilkin

Document type:: Monograph

Structure type:: Chapter

together with any desired combination of the output recording devices* Th*' use of the system in conjunction with different photo grammetrie instruments impose certain requirements on its most important component, namely, the encoder* Photogrammetrie work on precision stereocomparators needs a discrete value of conversion equal to 1-2 umj for stereocoiu- parators belonging to the 2 nd class of accuracy and mechanical universal photogrammetrie instruments, this value amounts to 4-5 nm, and for devices picking-up data from maps, to 10 urn* A higher resolution requirement is in direct connection with the accuracy of conversion of an analog value tc digital code. At present, photogrammetrie instruments developed in the So viet Union use two types of encoders: linear displacement-code and angular rotation-code. The encoders of the first type give more accuracy, since physical principles they rely on allow for direct conversion of a linear displacement into a code. The encouers of the second type are coupled with load screws of photogrammetrie instruments. The intermediate transformation of a linear quantity into an angular one affects measurement results, since surplus errors, both systematic and random, are introduced. However, with accurately made lead sccews, suen features of the angle-code encoder as simple'and reliable de sign allow for its use even in precision stereocomparatcrs. A diffraction type linear displacement encoder used in stereocomparator CKB-1 is an example of a lineur-to-coae encod er applicable to px^ecision photograrmetrie instruments. A distinctive feature of this encoder, as compared with a well known diffraction type Fexxranti encoder, is the use of two gratings, transparent and reflecting one. This ensures better characteristics of the encoder and provides for its higher performance. For instance, with the value of a moire fringe equal to 4 urn and a gap between tne gratings - of 20 mm, the fringe contrast amounts to 0.7* In addition, the encoder is not affected by the size of the luminous element and adjust ment. errors. An optical schematic of the encoder of stereocom parator is shown in Fig. 1. Reflecting difraction grating 1

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