Lidar stands for light detection and ranging. Lidar imagery is created with a laser beam composed of a very narrow light band.

Transcription

1 Lidar stands for light detection and ranging. Lidar imagery is created with a laser beam composed of a very narrow light band. This light can be transmitted over large distances.

2 Normal light is composed of many wavelengths (top) Laser light is coherent or composed of a narrow range of wavelengths.

3 Green and infrared are most commonly used because this light reflects best from vegetation.

4 Diagram of simple laser. Lasers use mirrored surfaces to increase the intensity of light before it leaves the laser.

5 Lidar echoes can provide a profile of the ground elevation (a) Vegetation structure can also be determined from the data (b)

6 Several returns from vegetation are recorded to provide details on tree height.

7 Lidar data is acquired in parallel strips and forms a continuous image. Light tones are higher elevations (top). The lower image has be processed using a hill-shading technique.

8 Raw lidar data (top) Lidar image process using hill-shading technique (bottom)

9 Raw lidar data (left) Lidar image process using hill-shading technique (right)

10 Thermal infrared imagery is created from heat energy. It is also called farinfrared energy.

11 A model of an energy sensor or radiometer. The radiation refers to thermal energy. The thermal energy data is stored with electronics in this situation.

12 The smallest area of view is the IFOV and corresponds to image resolution. This scanner is scanning side to side across the flight path.

13 Newer Thermal IR Cameras

14 Thermal Aerial Vehicle

15 Blackbody: theoretical object that absorbs and reemits all of the energy that it receives. Emissivity: indicates how much energy an object radiates at a given temperature

16 A model of a thermal scanner. Heat energy is sensed, focused, calibrated, amplified and recorded.

17 Thermal images have separate nadirs for each scan line. Relief displacement and tangential distortion increases with distance from the nadir.

18 Discharge of warm water into the Delaware River by a petroleum storage facility

19 The same facility in a different area. Notice the heat radiating from tanks and the ship.

20 Thermal images of Cornell University showing heated buildings, underground pipelines, cars and more.

21 Aerial photo and thermal image of Painted Rock Dam in Arizona at 7:0 0 A.M.. The light area on the bottom indicates water that is warmer than the surrounding land. This situation occurs overnight usually.

22 Thermal images showing the rising and subsiding tidewaters. The third image shows the area at high tide.

23 The diurnal cycle showing the variations in temperature during the day of four different earth surfaces. Sand is warmest during the day. The meadow is coolest at sunrise.

24 General diurnal cycle of land and water as seen by satellite.

25 March and October thermal images showing the contrasts between land and water temperatures.

26 Daytime Thermal Image of San Francisco: warm surfaces are lighter

27 Buried Heating Lines at Night: warmer lines appear lighter

28 Daytime Thermal Image: Cloud shadows areas are cooler than exposed land areas

29 Daytime Thermal Image Sacramento: solar radiation masks thermal output from earth surfaces

30 Night Thermal Image Sacramento: thermal radiation is more evident at night

31 Thermal Discharge from Nuclear Power Plant: Haddam Downstream: Night Upstream: Day

32 Nighttime Thermal: Oilslick

33 Predawn: Springs and Streams: water may be warmer than land at night

34 Top: Red band Bottom: Thermal IR at night. Crops may retain more heat than bare soil

35 Wildfires in Montana: Nighttime

36 Wildfires in Canada: Night

37 Heat Loss From Roofs

38 Home Heating Loss

39 Security Applications

40 Thermal image of World Trade Center

41 Thermal image of power generators at Hoover Dam

42 Thermal image of people and trees

43 Thermal image of London estate

44 Thermal Dog