using dss digital camera images and dТm from als50 laser scanner for creating orthomosaics in...

Using DSS digital camera images and DТM from ALS50 laser scanner for

creating orthomosaics in PHOTOMOD system

Dmitry V. Кochergin (Racurs), Maxim V. Skorniakov (Mosgiprotrans)

On-board data + software

Digital aerial imagesExterior orientation parametersDTM from Laser scanner

TerraScan softwarePHOTOMOD software

PHOTOMOD 4.1 – automatic interior orientation of images from the digital camera

PHOTOMOD 4.1 – importing exterior orientation parameters from Applanix format

PHOTOMOD 4.1 – block layout creation fromthe exterior orientation parameters

PHOTOMOD 4.1 – automatic tie points measurements using the block layout

PHOTOMOD 4.1 – import of laser scanner datafrom LAS format

+ automatic tie points measurements

+ automatic tie points measurements

+ ground control points

Digital aerial images, Exterior orientation parameters, DTM from Laser scanner

Orthomosaics of different accuracy

Input, processing, output

direct georeferencing block adjustment

reconstruction of existing highways and railroads and projecting new ones

aerial survey: • DSS camera (focal length = 35 mm)• Applanix • ALS 50

• Flight height 300 m• Air vehicle Mi-8 helicopter• Total length 180 кm • Aerial survey productivity 150 km per day• Velocity 120-150 km\h

one of the projects in 2006:

output products:• DEM• Orthomosaics of 1:1000 scale• 3D vector objects

MOSGIPROTRANS Co. is the biggest Russian institute of exploration and projecting of transportation objects

How does it look like

Calibration of DSS-ALS50 system was done in accordance with standard Applanix technology on the special polygon

Project geodetic works

GCPs (also for more precise field survey and calculation of accurate local datum parameters)

Tacheometry

Base stations for ALS and DSS (Applanix postprocessing)

“Moscow” coordinate system

PHOTOMOD 4.1. One of project strips (35 images)

PHOTOMOD 4.1. Automatic interior orientation

PHOTOMOD 4.1. Block layout after importing Applanix data

PHOTOMOD 4.1. Automatic tie points measurements

PHOTOMOD 4.1. Automatic tie points measurements

PHOTOMOD 4.1. Block adjustment

TerraScan. All points

~8 points / sq.m~720 000 points / image

TerraScan. “Ground” points

~2 points / sq.m~180 000 points / image

TerraScan. “Model key” points

~0.2 points / sq.m~18 000 points / image

PHOTOMOD 4.1

PHOTOMOD 4.1 Laser scanner data

The biggest LAS file imported to PHOTOMOD was about 5 000 000 points

PHOTOMOD 4.1

PHOTOMOD 4.1 DEM from laser scanner data

PHOTOMOD 4.1 DEM from laser scanner data

PHOTOMOD 4.1 Orthomosaic

PHOTOMOD 4.1 Orthomosaic

+ automatic tie points measurements

+ automatic tie points measurements

+ ground control points

orthomosaic accuracy by check points (max residual)

30 cm 25 cm 15 cm

Digital aerial images, Exterior orientation parameters, DEM from Laser scanner

Accuracy and productivity

Total time for 35 images project processing is about 10 hours

direct georeferencing block adjustment

Thank you for attention!