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8/6/2019 camaras fotogrametricas (2) - copia
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Jonas Nelson
Analog Aerial Cameras
SensorsZ/I DMC
Leica ADS40Comparison
2.6 * H104 (116 gon)88 mmSuperwide
1.5 * H73 (82 gon)152 mmWide angle
1.1 * H57 (63 gon)210 mmNormal angle
0.8 * H41 (46 gon)300 mmNormal angle
0.4 * H22 (24 gon)600 mmNarrow angle
Ground coverageOpening anglecLens type
Main manufacturers are Wild and Leica.All use film size 230x230 mm.
Jonas Nelson
AnalogAerialCameras
SensorsZ/I DMCLeica ADS40Comparison
It is not just onelens, but a set ofabout 10-12 lensesthat make up theaerial camera lenssystem.
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AnalogAerialCameras
SensorsZ/I DMC
Leica ADS40Comparison
Actually, a camerahas TWO perspectivecenters, one at the
front of the cameraand one at the rear.
Jonas Nelson
Image Info
SensorsZ/I DMCLeica ADS40Comparison
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Sensor Types CCD pushbroom
For colour images they use one for Red,one for Green and one for Blue.= three-line scanner.
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
Sensor Types CCD array
2D CCD arrays can be black/whiteor use filters to capture colour.
SensorsZ/I DMCLeica ADS40Comparison
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Jonas Nelson
All sensors are black/white
Each light-sensitivepixel is identical, imagesensors record onlythe gray scale.Basically, they onlycapture brightness.
In order to get colour,you have to addcoloured filters infront of the sensors.These filters will ofcourse steal some ofthe transmitted light.
On the Fuji SuperCCD there are small lensesconcentrating the light before passingthrough the filters and reaching the pixels.
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
CCD array designs
A typical CCD imagesensor has squarephotosites arrangedin rows and columns.
The Super CCD fromFuji uses octagonalpixels arranged in ahoneycomb pattern.
SensorsZ/I DMCLeica ADS40Comparison
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CMOS chip properties
CMOS image quality is now matching CCD quality in thelow- and mid-range, leaving only the high-end image sensorsstill unchallenged.
CMOS image sensors can incorporate other circuits onthe same chip, eliminating the many separate chipsrequired for a CCD.Not only does this make the camera smaller, lighter, andcheaper; it also requires less power so batteries lastlonger.
CMOS sensors have a higher noise level than CCDs so theprocessing time between pictures is higher as thesesensors use digital signal processing (DSP) to reduce oreliminate the noise.
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
CMOS chip properties
CMOS sensors suffer in low light conditions. Theirsensitivity to light is decreased because part of eachphotosite is covered with circuitry that filters out noiseand performs other functions.
The percentage of a pixel devoted to collecting light iscalled the pixels fill factor.
CCDs have a 100% fill factor but CMOS cameras havemuch less. The lower the fill factor, the less sensitivethe sensor is and the longer exposure times must be.
SensorsZ/I DMCLeica ADS40Comparison
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Comparison: CCD - CMOS
- Mass-production like IC.- Cheap (1/3 of the CCD).- Integrated with circuitsdoing signal processing.
- Requires more light.- Slower due to more noise.
- Special production lines.- Expensive.- Separate chips for processing.- Requires more power.- Higher quality than CMOS.
Both CCD and CMOS imagesensors capture light on a gridof small pixels on theirsurfaces.
It's how they process the imageand how they are manufacturedwhere they differ from oneanother.
CCD CMOSSensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
Camera Design Options
One Array
Black and White
Colour Bayer Matrix
Three-layer chip - Foveon
Multi Array
1 lens + multi-chip
Multi-lens with 1 chip each
SensorsZ/I DMCLeica ADS40Comparison
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Bayer Mosaic Pattern
There are twice as many green filters as there arered or blue filters. That's because a human eye ismore sensitive to green than it is to the other twocolors so green's color accuracy is more important.
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
Bayer Mosaic Interpolation
"I'm bright green and the red and bluepixels around me are also bright so thatmust mean I'm really awhitepixel."
SensorsZ/I DMCLeica ADS40Comparison
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Foveon three-layer CMOS
Similar to a colour film, the Foveon three-layer CMOS has semi-transparent layerssensitive to different colours.
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
SensorsZ/I DMCLeica ADS40Comparison
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Multiple Chip Design
Beam Splitter
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
Airborne Digital Sensors
Z/I DMC Leica ADS40
Applanix DSS
Vexcel UltraCam D
SensorsZ/I DMCLeica ADS40Comparison
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Z/I DMC
SensorsZ/I DMC
Leica ADS40Comparison
4 panchromatic CCD arrayseach 7000 x 4000 pixels,Final image 13824 x 7680
4 multispectral (R,G,B, NIR)CCD arrays,each 3000 x 2000 pixels
Pixel size: 12 m x 12 m
Field of view (FoV) or swathangle: 69.3across strip,
42along strip
Focal length: 120 mm (pan)25 mm (MS)
Stereo angle: 42
Jonas Nelson
Z/I DMC - cameras
4 panchromatic high-resolution (7000x4000) CCD cameraheads, covering a quarter each. Focal length 120 mm.
4 multispectral (R, G, B, Near IR) CCD camera headswith 3000x2000 pixel resolution each. Focal length 25 mm.
SensorsZ/I DMCLeica ADS40Comparison
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Z/I DMC panchromatic cameras
To speed up reading of the sensors, each sensor has itsdata downloaded from all four corners.Still takes 2.1 seconds / image.
12x12 micrometer pixel size.
Radiometric resolution is 12 bit (4096 levels).
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
Z/I DMC camera placement
SensorsZ/I DMCLeica ADS40Comparison
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Z/I DMC camera placement
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
Z/I DMC - footprint
7680 pixel
13824pixel
SensorsZ/I DMCLeica ADS40Comparison
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Z/I DMC the virtual image
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
Z/I DMC the virtual image
SensorsZ/I DMCLeica ADS40Comparison
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Z/I DMC mosaic
Left: Virtual image center after:
- tie point extraction & matching- lens corrections- rectification
A perfect geometric match!
Right: Virtual image centerafter applying radiometriccorrection / blending of thefour images.
The final product is a verygood mosaic!
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
Global radiometric correction
Standard radiometric correction(changing the grey values throughhistogram equalization).
SensorsZ/I DMCLeica ADS40Comparison
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Local radiometric correction
Defect column (no data; black) in the sensor isradiometrically corrected through interpolationtechniques.
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
Local radiometric correction
Defect area in the sensor (darker) is
radiometrically corrected automatically since it issystematic (you always know which pixels andhow much to correct them).
SensorsZ/I DMCLeica ADS40Comparison
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Z/I DMC stereo model
Two consecutive virtual images (left + right) workas a normal stereo model. However, the B/Hratio is lower due to sensor size.
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
Leica ADS40
3 panchromatic CCD lineseach 2 x 12,000 pixels,staggered by 3.25 m
4 multispectral CCD lines,each 12,000 pixels
Pixel size: 6.5 m x 6.5 m
Field of view (FoV) or swathangle: 64(across strip)
Focal length: 62.77 mm
Stereo angles: 16, 26, 42
Sensor head SH40
SensorsZ/I DMCLeica ADS40Comparison
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Leica ADS40 system
GPS satellites
GPS ground reference station
ADS40 system
1
2
34 5
6
1 Sensor head SH40 with:
- Digital optics DO64- IMU
2 Control unit CU40 with:- position & attitudecomputer POS
3 Mass Memory MM40
4 Operator interface OI40
5 Guidance Indicator GI40
6 Mount PAV30
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
Leica ADS40 - sensors
3 panchromatic 12000 pixel line scanners (forward, nadir, back)
4 RGB+NIR 12000 pixel line scanners
SensorsZ/I DMCLeica ADS40Comparison
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Leica ADS40 - panchromatic
3 panchromatic line scanners = three seamless image strips.
Forward 26 , nadir 0 and backward 16 .
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
Leica ADS40 pan level 0 and 1
The output (raw data, level 0) from an airborne line scanner hasa jumbled appearance; the ground footprints are not parallel,owing to the movement of the aircraft. This is rectified using datafrom GPS and IMU.
SensorsZ/I DMCLeica ADS40Comparison
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Leica ADS40 multispectral
Ideal bands for remote sensing applications should be narrowand non-overlapping, whereas the requirement for high qualitytrue-colour images dictates broad, overlapping bands.
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
Leica ADS40 RGB beam splitter
A tri-chroid beam splitterensures that the incomingRGB light from the samearea of the ground isregistered in all three RGBarrays.
This means perfect RGBco-registration and betterresolution for each colour,compared to sensors withBayer pattern.
SensorsZ/I DMCLeica ADS40Comparison
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Leica ADS40 radiometric correction
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
Multispectral comparison
SensorsZ/I DMCLeica ADS40Comparison
Ideal bands for remote sensing applications should be narrow
and non-overlapping, whereas the requirement for high quality
true-colour images dictates broad, overlapping bands.
Pan (no info) 465-680 nmBlue 400-580 nm 430-490 nmGreen 500-650 nm 535-585 nmRed 590-675 nm 610-660 nmNear IR 675-850 or 740-850 nm 835-885 nm
DMC ADS40
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Airborne / Spaceborne comparison
SensorsZ/I DMC
Leica ADS40Comparison
Jonas Nelson
DPWS System Manufacturers
1E1440Lecture 1
PhotogrammetryZ/I, Leica, ESPA, Geosystems, Inpho
Remote SensingI2S, ERDAS, PCI, ERMapper, TNTmips,Vexcel
Digital CartographyDAT/EM, ISM
MilitaryHelava, Intergraph, Automatrics
UniversityDMS, DVP, VirtuoZo...
HistoryTerminologyDigital ImagesResolutionManufacturersComponents
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DPWS in the center
1E1440Lecture 1
HistoryTerminology
Digital ImagesResolutionManufacturersComponents
Vector data
Satelliteimages
RadarimagesScanned
aerial images
CCD,Video Laser
scanner
Existingmap data
ExistingDEM Digital
PhotogrammetricWorkStation
GISWorkStation
Classedsatellitescenes
Raster data
Attributes,
tables
Triangulation,orientation data
DEMContoursProfiles Ortophoto
Digitalmap data
CAD, AutoCAD
Operator
Jonas Nelson
Leaving the hardware
1E1440Lecture 1
HistoryTerminologyDigital ImagesResolutionManufacturersComponents
The early stages (1988-1996) saw a lot ofintegrated hardware+software stand-alonesolutions (dedicated hardware).
Now, the computer development have made
the photogrammetric companies focus onsoftware, often on multiple platforms(Unix/Windows).
But the software is expensive since it is sospecialised and sold in few copies.
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Buy it all - or transform your PC
1E1440Lecture 1
Z/I Image Station- Dual 21" monitors
- Dual Pentium Processors
- Win 2000
- 3Dlabs Wildcat graphics card
-Emitter
- CrystalEyes
- 3D Mouse Hardware cost:
About 10 000 USD
Z/I Stereo Softcopy Kit- Emitter
- CrystalEyes
- Graphics card
- 3D mouse (Immersions 3D softmouse) Hardware cost: About 3000 USD
HistoryTerminology
Digital ImagesResolutionManufacturersComponents
Jonas Nelson
System Components
1E1440Lecture 1
HistoryTerminologyDigital ImagesResolutionManufacturersComponents
Central Processing Unit (CPU). Should be fast!
Operative System (OS). 32-bit real-time processing.
Main Memory (RAM). 256 Mb is a minimum.
Storage. Hard disc of several Gb. Slower mass storage.
Graphics Display System. Graphics card and monitor(s).
3D Viewing System. Stereo viewing in colour if possible.
3D Measuring Device. See User Interface below.
User Interface. GUI, keyboard, mouse, trackball, handwheels.
Network. Scanner, printer, GIS, internet.
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Memory Components
1E1440Lecture 1
HistoryTerminology
Digital ImagesResolutionManufacturersComponents
Monitor, 4 Mb+ (1/60)
Graphic card, 16 Mb+ (1/15 image)
RAM, 256 Mb+ (1 image)
Hard disc, 20 Gb+ (86 images)
Peripheral mass storage, 100 Gb+ (425 images)
(23x23 cm aerial image, 8-bit b/w with 15 m pixel size)
Jonas Nelson
3D Viewing
1E1440Lecture 1
HistoryTerminologyDigital ImagesResolutionManufacturersComponents
The human brain requiresseparation of stereoimagesin order to get a 3D view.
Separation method Practical implementation
Spatial 2 monitors + stereoscope1 monitor (split screen) + stereoscope2 monitors + passive polarisation
Spectral AnaglyphicPassive polarisation
Sequential Alternated synchronised display,active polarisation or LCD
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3D Viewing pros and cons
1E1440Lecture 1
HistoryTerminology
Digital ImagesResolutionManufacturersComponents
Implementation Advantage / Disadvantage
2 monitors - Bulky- Only one observer
Split screen - 50% Field of Vision+ stereoscope - Only one observer
Anaglyphic - No colour images + Several observers- Bad transmission + Very cheap
Passive - 50% resolution + Several observerspolarisation - High initial cost + Cheap glasses
LCD and Active - 50% resolution + Several observerspolarisation - Expensive glasses
- Flickering
Jonas Nelson
Polarisation screen + glasses
1E1440Lecture 1
HistoryTerminologyDigital ImagesResolutionManufacturersComponents
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Split-screen + stereoscope
1E1440Lecture 1
HistoryTerminology
Digital ImagesResolutionManufacturersComponents
GeoSystem
Delta DPS from GeoSystem (Ukraine)(Also available with 3D glasses)
Note the hand- and footwheels!
Jonas Nelson
Monitor requirements
1E1440Lecture 1
HistoryTerminologyDigital ImagesResolutionManufacturersComponents
24 bit monitor for viewing colour images.
120 Hz for good refresh rate withsequential stereo viewing.
1-2 million pixels required (minimum). 1280x1024.
The resolution may determine the accuracy. One (large) or two monitors. 21+
More than two images can be shownsimultaneously.
Overlays of graphic (map data) in 2D or 3D.
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3D measuring devices
1E1440Lecture 1
HistoryTerminology
Digital ImagesResolutionManufacturersComponents
Mouse
Mouse + trackball
Hand- and footwheels
(from analytical instruments)
Rat (device from analytical instrument)