Beyond Spectral and Spatial data: Exploring other domains of information: 4 GEOG3010 Remote Sensing and Image Processing Lewis RSU
Jan 29, 2016
Beyond Spectral and Spatial data: Exploring other domains of
information: 4
GEOG3010 Remote Sensing
and Image Processing
Lewis
RSU
Domains of Information
• spectral
• angular
• multi-temporal
• distance-resolved
• spatial
Distance-resolved
• Can determine distance from satellites:– based on time-delay of signal
Distance-resolved
• Can determine distance from satellites:– based on time-delay of signal
Distance-resolved
• eg GPS
Distance-resolved
• EO example:– radar interferometry
Distance-resolved• EO example:
– radar interferometry: • assume know satellite position
1 cycle (5.6 cm for C band)
¾ way through half cycle
(¾+1)x180 = 315 degrees
(360 degrees, 2 radians)
¾ way through
270 degrees
2 x d1 = (N1+¾)x5.6
Distance-resolved• EO example:
– radar interferometry:
0 way through2 x d2 = (N2) x 5.6
2 x (d2 - d1) = (N2- N1) x 5.6 + (¾-0) x 5.6
Distance-resolved• EO example:• position 1:
– 2 x (d2 - d1) = (N2- N1) x 5.6 + (¾-0) x 5.6
• position 2:– point on ground next to current point will have different
phase change– if its within the same cycle (height change less than
5.6cm)• can tell relative height change between these points• very precise (mm)
Shuttle Radar Topography Mission
Shuttle Radar Topography Mission
11 Feb 2000 (Endeavour) - 11 days
30m DEM of +/- 60 degrees latitude
Distance-resolved
Measure small change -
subsidence
Distance-resolved
Measure small change -
earthquake
Distance-resolved
LIght Detection And Ranging
RAdio Detection And Ranging
LIDAR
RADAR
Distance-resolved LIDAR
• Send laser pulse from sensor
• measure round trip time
• = 2x distance
• use NIR mostly– atmospheric effects minimised
Distance-resolved LIDAR
• Examples - EA
• fly aiborne LIDAR regularly for high resolution DEM
• use first/last return
• ground height / tree height
Distance-resolved - LIDAR
Distance-resolved LIDAR
• Examples - VCL
• Vegetation Canopy LIDAR
• NASA mission to fly ????
• waveform LIDAR
Distance-resolved VCL
• waveform LIDAR
Distance-resolved • waveform LIDAR
LIDAR
• ‘Simple’ form of measurement
• easy to use (? Simply)
• doesn’t work (well) on high slopes
• requires highly-sensitive instrumentation
• potentials for new forms of information – waveform LIDAR
Interferometry
• Used for number of years– operational (SRTM)
• different ‘scales’ for different SAR frequencies
• doesn’t work well (for height) if change between images– wind in forests
• doesn’t work on high slopes