The fundamental of Photogrammetry

Submitted byVIPIN SOLANKI11411360

TERMINOLOGY'photo' - light'gram' - drawing'metry' – measurement

Photogrammetry = “photo-measurement”

PHOTOGRAMMETRY

INTRODUCTIONBASIC DEFINITIONPHOTOGRAMMETRY IS THE SCIENCE AND ART OF DETERMINING THE SIZE AND SHAPE OF OBJECTS BY MEANS OF ANALYSING IMAGES RECORDED ON FILM OR ELECTRONIC MEDIA.

PHOTOGRAMMETRY HAS BEEN DEFINED BY THE “AMERICAN SOCIETY FOR PHOTOGRAMMETRY AND REMOTE SENSING”(ASPRS) AS THE ART SCIENCE AND TECHNOLOGY OF OBTAINING RELIABLE INFORMATION ABOUT PHYSICAL OBJECTS AND THE ENVIRONMENT THROUGH PROCESSES OF RECORDING,MEASURING AND INTERPRETING PHOTOGRAPHIC IMAGES AND PATTERNS OF RECORDED RADIANT EM ENERGY AND OTHER PHENOMENA.

Relationships of the Mapping Sciences as they relate to Mathematics and Logic, and the Physical, Biological,

and Social Sciences

HISTORY OF AERIAL PHOTOGRAPHY

Photogrammetric TypesPhotogrammetric Types from Applications Point of View (d is distance from camera to object)

Close Range Photogrammetry d<10 mTerrestrial Photogrammetry 10 m<d<100 mAerial Photogrammetry 2 km<d<10 kmSpace Photogrammetry 30 km<d

Types of Images

• Panchromatic, Black & White, Grayscale

• Color RGB

• Multispectral

• Hyperspectral

Types of photographs (categorized by tilt)

TILT:-TILT IS AN ANGLE BETWEEN THE OPTICAL AXIS OF THE CAMERA AND THE PLUMB LINE OR IT IS ALSO THE ANGLE BETWEEN THE GROUND PLANE AND THE PHOTO PLANE.

Types of photographs (categorized by tilt)

•Vertical - camera axis as nearly vertical as Possible

•Oblique - camera axis intentionally tilted

• Low Oblique• High Oblique

VERTICAL PHOTOGRAPH->IT IS OBTAINED WHEN THE CAMERA ‘S OPTICAL AXIS IS WITHIN 3 DEGREE OF BEING VERTICAL TO THE EARTH’S AXIS.

LOW OBLIQUE PHOTOGRAPH->OBTAINED WHEN THE CAMERA’S OPTICAL AXIS DEVIATES MORETHAN 3 DEGREE FROM VERTICAL AXIS.& HORIZON IS NOT VISIBLE

HIGH OBLIQUE PHOTOGRAPH->DEVIATES MUCH MORE (AROUND 60 DEGREE) AND HERE HORIZON IS VISIBLE

VERTICAL PHOTOGRAPH-

LOW OBLIQUE PHOTOGRAPH-

HIGH OBLIQUE PHOTOGRAPH-

Vertical Aerial Photogrammetry

Mainly used for mapping

Low Oblique

High Oblique• Horizon line

in the photo

Taking Vertical Aerial Photographs

• Photos taken in parallel flight strips

Taking Vertical Aerial Photographs

• Each successive photograph overlap previous photo

OVERLAPPING IN AERIAL PHOTOGRAPHOVERLAP: OVERLAP INCLUDES THE AMOUNT OF PHOTOGRAPH IN WHICH ONE PHOTOGRAPH INCLUDES SAME AREA COVERED BY ANOTHER AND IS CUSTOMARILY EXPRESSED AS A PERCENTAGE.FORWARD OVERLAP AND SIDE OVERLAP:

Forward Overlap (End Lap)

Side Overlap (Side Lap)

Advantages Photogrammetry

• Extracting geometrical information and producing maps.

• Cheaper than terrestrial methods.

• Extracting qualitative information.

• High speed of map generation.

• Cover areas quickly

CONCLUSIONClose-range photogrammetry is being used more and more as a technique for measuring and modelling objects. It is relatively quick and easy to set up, requiring, in its simplest form, simply a digital camera and a compatible software product. In this project there has been an introduction to close photogrammetry and some of its applications, leading to an investigation into how the accuracy of object coordinates can be optimized through the network design of camera stations, with a particular focus on the elements of a camera network which strengthen or weaken it.