partha assignment ppt on photogrammetry

SUBMITTED TO SUBMITTED BYDr.Vijay Krishnae Partha Pratim NathAssistant Professor M.Sc (Tech)Semester1RGSC-BHU Roll No-13480RGO13

BANARAS HINDU UNIVERSITY RAJIV GANDHI SOUTH CAMPUS

BARKACHHA MIRZAPUR

FACULTY-INSTITUTE OF ENVIRONMENT AND SUSTAINABLE DEVELOPMENT (IESD

TOPIC-ASSIGNMENT ON”PHOTOGRAMMETRY”

PHOTOGRAMMETRY BASIC DEFINITIONPHOTOGRAMMETRY IS THE SCIENCE AND ART OF DETERMINING THE SIZE AND SHAPE OF OBJECTS BY MEANS OF ANALYSING IMAGES RECORDED ON FILM OR ELECTRONOC 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.

TYPES OF PHOTOGRAMMETRY

(BASED ON CAMERA LOCATION )

AERIAL PHOTOGRAMMETRY:-

THE CAMERA IS MOUNTED IN AN AIRCRAFT AND IS USUALLY POINTED VERTICALLY TOWARDS THE GROUND .MULTIPLE OVERLAPPING PHOTOS OF THE GROUND ARE TAKEN AS THE AIRCRAFT FLIES ALONG A FLIGHT LINE. (DIGITAL ELEVATION MODELLING)

CLOSE RANGE PHOTOGRAMMETRY:-

HERE THE CAMERA IS CLOSE TO THE SUBJECT AND IS TYPICALLY HAND HELD OR ON A TRIPOD.HERE THE OUTPUT IS NOT TOPOGRAPHIC MAPS BUT INSTEAD DRAWINGS ,3DMODELS MEASUREMENTS AND POINT CLOUDS. (IMAGE BASED MODELLING)

PHOTOGRAMMETRY

(ON THE BASIS OF TECHNIQUES)

ANALOG PHOTOGRAMMETRY:-IT IS PERFORMED VISUALLY BY HUMANS AND IS USED WHEN THE DATA ARE IN A HARD COPY FORMAT SUCH AS A 9 X 9 IN AERIAL PHOTOGRAPHIC PRINT OR POSITIVE TRANSPARENCY.

DIGITAL PHOTOGRAMMETRY:-IT IS PERFORMED WITH THE HELP OF COMPUTER USING DIGITIZED AERIAL PHOTOGRAPHY.

PHOTOGRAMMETRY

(ON YHE BASIS OF DIRECTION OF CAMERA AXIS)

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

PHOTOGRAMMETRY(ON THE BASIS OF ANGLE)

NARROW ANGLE=>40 DEGREE FIELD OF VIEW

NORMAL ANGLE=>70 DEGREE FIELD OF VIEW

WIDE ANGLE=>90 DEGREE FIELD OF VIEW

SUPER WIDE ANGLE=>110 DEGREE FIELD OF VIEW

PHOTOGRAMMETRY

(ON THE BASIS OF MULTIPLE CAMERA

PHOTOGRAPH)

CONVERGENT PHOTOGRAPH :THIS ARE DONE WITH A SINGLE TWIN LENS WIDE ANGLE CAMERA OR WITH TWO SINGLE LENS WIDE ANGLE CAMERA COUPLED RIGIDLY IN YHE SAME MOUNT.

TRIMETROGEN PHOTOGRAPH :THIS IS AN ASSEMBLAGE OF 3 PHOTOGRAPHS TAKEN AT A SAME TIME,1 VERTICAL AND 2 HIGH OBLIQUES IN A DIRECTION AT RIGHT ANGLE TO THE LINE OF FLIGHT.

INFORMATION RECORDED ON AERIAL

PHOTOGRAPHY

o GENERALLY 7 INFORMATION ARE RECORDED IN AERIAL PHOTOGRAPHY.THESE ARE ::-

• FIDUCIAL MARKS(ARE MARKS ON THE EDGES OF THE CAMERA FIELD.THEY DEFINE THE CAMERA COORDINATE SYSTEM BY MEANS OF THE COORDINATE VALUES FOUND ON CAMERA CALIBRATION CERTIFICATE)

• ALTIMETER(AN INSTRUMENT TO MEASURE THE ALTITUDE OF AN OBJECT ABOVE A FIXED LEVEL)

• CLOCK(DATE & TIME)

• BUBBLE LEVEL(INDICATE WHETHER THE SURFACE IS HORIZONTAL OR VERTICAL,ALSO INDICATE TILTNESS)

• FOCAL LENGTH OF LENSE

• CAMERA NUMBER

• NEGATIVE NUMBER

GEOMETRY OF AERIAL PHOTOGRAPHY

GENERALLY THREE PROJECTIONS ARE THERE:

PARALLEL PROJECTION:- PARALLEL PROJECTIONS HAVE LINES OF PROJECTION THAT ARE PARALLEL BOTH IN REALITY AND IN THE PROJECTION PLANE.

ORTHOGONAL PROJECTION:- THE TWO DIMENSIONAL GRAPHIC REPRESENTATION OF AN OBJECT FORMED BY THE PERPENDICULAR INTERSECTION OF LINES DRAWN FROM POINTS ON TO THE OBJECT TO A PLANE OF PROJECTION.

CENTRAL PROJECTION:- THE PROJECTION FROM A POINT ONTO A PLANE IS CALLED CENTRAL PROJECTION.

TILT IN AERIAL PHOTOGRAPHY

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.

GEOMETRY OF TILTED AERIAL

PHOTOGRAPH

TYPES OF TILT

TYPES OF TILT:-

X-AXIS TILT-> THE TILT ABOUT THE Y AXIS i .e IN THE DIRECTION OF

‘X’ IS CALLED LONGITUDINAL TILT OR ‘FORE & AFT TILT’

Y-AXIS TILT-> THE TILT ABOUT THE X AXIS i. e IN THE DIRECTION OF

‘Y’AXIS IS CALLED Y TILT OR LATTERAL TILT OR SIMPLE TILT.

REASONS FOR TILT:-

Atmospheric condition Human error Imperfection in

camera mounting

GEOMETRY OF UNTILTED AERIAL

PHOTOGRAPH

OVERLAPPING IN AERIAL

PHOTOGRAPH

OVERLAP: 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:

OVERLAP

SCALE MEASUREMENT IN

PHOTOGRAMMETRY

VERBAL SCALE S= ab /AB S=distance between two objects on photo/distance between two objects on ground ab =0.113in AB=56.1ft(0.113/56.1) Therefore,1 inch=496.46ft REPRESENTATIVE SCALE S=O.113in/56.1ft S=O.113in/(56.1)*12in S=1/5957.52 THUS, RF=1:5957

SCALE MEASUREMENT BY FOCAL LENGTH OF LENSE

AND ALTITUDE ABOVE GROUND LEVEL

S=f/HIF , f=12 inH=60,000ftVERBAL SCALE(S)=12/60,000V.SCALE=>1 in=5000ft

We know,12in=1ftREPRESENTATIVE FRACTION=>1:60,000

o S min=f/(H-h min)o S avg =f/(H-h avg )o S max=f/(H-h max)

SCALE MEASUREMENT IN VARIABLE TERRAIN

RELATION OF PHOTO TO GROUND THROUGH

MAP

• R.F OF PHOTO = PHOTO DISTANCE(P)/GROUND DISTANCE(G)

R.F OF MAP MAP DISTANCE(M)/GROUND DISTANCE(G)

R.F OF PHOTO = (P/M) X R.F OF MAP

CONCLUSION

• Close-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-range photogrammetry and some of its applications, leading to an investigation into how the accuracy of object coordinates can be optimised through the network design of camera stations, with a particular focus on the elements of a camera network which strengthen or weaken it.