Some Aspects of Digital Cameras Usage

Andrej Yu. Sechin, Scientific Director, Racurs

VIIIth International Scientific and Technical Conference

From Imagery to Map: Digital Photogrammetric Technologies

September 15-18, 2008, Porec, Croatia

Samples of Digital CamerasSamples of Digital Cameras

150/10000

N/A15

N/A(15000x15000)

RC-30

100/13900

7.214400x9400

UltraCam X

60/8800

6.87200x5400

DSS

120/10000

1213500x8000

DMC

62.5/9600

6.512000ADS-40 (80)

F mm/pix

PixelSize (µm)

ImageSize

Camera

GSD GSD insteadinstead of image scale of image scale

1.1. RC-30RC-302.2. АФААФА3.3. DMCDMC4.4. DSSDSS

GSD = H (m) / F (pixels)GSD = H (m) / F (pixels)

GSD instead of image scaleGSD instead of image scale

0.74 FPS UltraCam

7.5 FPSVisionMap A3

0.35 FPSDSS

0.476 FPSDMC

N/AADS-40 (80)

Frame RateCamera

Minimal flying speedMinimal flying speedVmin = L*FPS = 0.4*FPS*H*(S/F)Vmin = L*FPS = 0.4*FPS*H*(S/F)

Cessna minimal flying speed isCessna minimal flying speed is40 knots (or 21 m/s, or 75 km/h)40 knots (or 21 m/s, or 75 km/h)

DMC minimal GSD ~ 4 cm, ADS-40 (SH-40) GSD ~ 15 cm (5 cm pan)DMC minimal GSD ~ 4 cm, ADS-40 (SH-40) GSD ~ 15 cm (5 cm pan)

Flying Height and GSDFlying Height and GSD

20 cm3000 * 3000

10 cm1500 * 1500

5 cm750 m * 750 m

RC-30/150/15µm

14.4 cm 2072 * 1352

7.2 cm1036 * 676

3.6 cm518 m * 338 m

UltraCam X

22.8 cm1640 * 1232

11.4 cm820 * 616

5.7 cm410 m *308 m

DSS

20 cm2700 * 1600

10 cm1350 * 800

5 cm675 m * 400 m

DMC

20.8 cm2700 m * ∞

10.4 cm1350 m * ∞

5.2 cm624 m * ∞

ADS-40 (80)

2000m1000m500mH/Camera

B/H ratioB/H ratio

0.61/0.31RC-30 F=150/300

0.27UltraCam X

0.25DSS

0.32DMC

0.29/0.49/0.78ADS-40 (80)

B/HCamera

Z accuracy:Z accuracy:dZ = c*GSD/(B/H)dZ = c*GSD/(B/H)c – image “quality”c – image “quality”

60% overlap60% overlap

Color in Digital CamerasColor in Digital Cameras

For Small and Medium FormatFor Small and Medium FormatDigital CamerasDigital Cameras

Bayer filterBayer filter

All images are fromhttp://ru.wikipedia.org

Color in Digital CamerasColor in Digital Cameras

For Large Format Digital For Large Format Digital Cameras:Cameras:

PansharpeningPansharpening

9UltraCam X

22DMC

1ADS-40 (80)

Pan/Multispectral pixel size ratio

Camera

IMU/GPS, Direct GeoReferencing, LIDARIMU/GPS, Direct GeoReferencing, LIDAR

GPS AccuracyGPS Accuracy

GPSGPSDGPSDGPS

PPP (PPP (Precise Point PositioningPrecise Point Positioning)

Table 1: Errors (RMS) of GrafNav PPPTable 1: Errors (RMS) of GrafNav PPP

6.96.95.55.55.85.8VerticalVertical

5.55.54.34.36.16.1HorizontalHorizontal

Flight 03Flight 03Flight 02Flight 02Flight 01Flight 01Errors (cm RMS)Errors (cm RMS)

IMU/GPS, Direct GeoReferencing, LIDARIMU/GPS, Direct GeoReferencing, LIDAR

LIDAR — may require the same or LIDAR — may require the same or more accurate IMUmore accurate IMULIDAR —LIDAR — can provide DEM without can provide DEM without photogrammetric stereo photogrammetric stereo processingprocessing

Δφ= 1/F ~ 0.006 (deg)Δφ= 1/F ~ 0.006 (deg)

IMU/GPS, Direct GeoReferencing, LIDARIMU/GPS, Direct GeoReferencing, LIDAR

Real project: Kstovo, Nizhegorodskij region, GSD = 9 cmReal project: Kstovo, Nizhegorodskij region, GSD = 9 cm

Orthophoto scaleOrthophoto scale: 1 : 2 000 Total images number: 1010 Direct Georeferencing accuracy: 17 cm

Orthophoto scale: 1 : 500 Total images number: 294 Bundle adjustment accuracy : 10 cm

All data was provided by Geokosmos company

What is upcoming?What is upcoming?

• Many systems (hardware and software) for oblique aerial Many systems (hardware and software) for oblique aerial photographyphotography

• Pushbroom aerial camera «3-DAS-1» by Wehrli/GeoSystem with 45Pushbroom aerial camera «3-DAS-1» by Wehrli/GeoSystem with 45º º viewsviews

Economical/Legal AspectsEconomical/Legal Aspects

• Economical aspects of Digital Cameras, GPS, IMU, LidarEconomical aspects of Digital Cameras, GPS, IMU, Lidar

• What Camera is best for…?What Camera is best for…?

• Digital Images Storage?Digital Images Storage?

Thank You for AttentionThank You for Attention