Lukas Paluchowski HySpex by Norsk Elektro Optikk AS

Transcription

1 HySpex Mjolnir the first scientific grade hyperspectral camera for UAV remote sensing Lukas Paluchowski HySpex by Norsk Elektro Optikk AS 1

2 Geology: Rock scanning Courtesy of CSIRO, Australia

3 Lab geology: Drill core scanning

4 Field geology: Mine face scanning Courtesy of CSIRO, Australia

5 Field Geology: University of Alaska - Fairbanks

6 HySpex Hyperspectral imaging systems for all applications The same instrument can be used for: Lab measurements Field/outdoor scanning Airborne Applications Industrial applications Field Airborne Lab Thus making it a very versatile instrument. Industrial

7 Outline Mjolnir system description (examples from Mjolnir-1240) Requirements for high accuracy georeferencing UAV platforms and gimbal Flight planning Real time georeferencing Field operations 7

8 Mjolnir Systems Key components: HySpex VNIR-1240 or SWIR-620 or VNIR+SWIR 620 sensor head PicoITX i7 computer Mjolnir controller card (IOs, shutter, frequency divider, 3,3V ->5V, APX interface) APX-15 UAV TCP/IP modems Gremsy gimbal Optional: Videolink HD RGB video camera FLIR Video camera (IR) 8

9 Mjolnir optical system is based on the high end ODIN-1024 instrument 9

10 Mjolnir V

11 Mjolnir S

12 Mjolnir VS

13 Mjolnirs: A generic camera system Mjolnirs come as a complete package with APX-15 INS solution. Can be interfaced to any navigation system (only requirement is an event input).. Compatible with most UAVs that can lift 5-7kg* *Depending on the selected model 13

14 HySpex spectrometer calibration and characterization Instrument calibration: Radiometric/sensor: -Dark signal (automatic shutter) -Pixel responsivity, nonuniformity -Bad pixels Spectral: -Wavelength as a function of sensor row number (band number) Geometric: -FOV pr pixel (for georeferencing) Instrument characterization: Radiometric/sensor: -Linearity -Noise, SNR, NER -Dynamic range -Stray light Spectral: -Spectral resolution, spectral misregistration Geometric: -FOV pr pixel (sensor model) -Total FOV -Spatial resolution, -Spatial misregistration All hyperspectral instruments should be delivered with: -Calibration data -Detailed test/calibration report -Sensormodel 14

15 Optical performance Spatial resolution 15

16 Optical performance Spectral resolution 16

17 Optical performance Spatial misregistration (Keystone) 17

18 Optical performance Spectral misregistration (smile) - at 400 bands 18

19 Performance and accuracies What is needed to get optimal georeferencing result? INS system with high performance Good GPS antenna Good timing accuracies Alignment of INS Boresight calibration High resolution DEM Gimbal Mechanical stability Since it s a pushbroom scanner we need longitude, latitude, altitude, roll, pitch heading for every scan line to rectify the images. 19

20 Performance and accuracies Navigation System Applanix APX-15 UAV The APX-15 provides the best weight/size/price/performance trade-off on the market Mjolnir will work with any external INS with an event input logging option. 20

21 Performance and accuracies - Alignment of INS Having all the hardware and timing accuracies mentioned above gives us the potential to get extremely good georeferencing results. For UAV flights we need to align the INS fast. We do this by first flying a straight line for 30s, then flying an 8-pattern. 21

22 Performance and accuracies Boresight calibration Performance and accuracies Boresight calibration Find offsets between the coordinate system of the camera and the coordinate system of the IMU. A good boresight calibration cannot be achieved without a good sensormodel. Need at least 20 GCPs on the ground Only necessary to do this once. After the offsets are found, direct georeferencing is straightforward without GCPs. 22

23 Performance and accuracies Georeferencing Accuracy Pixel size of Mjolnir 1240 is approx. ~0.27mrad. For post processed INS data we can achieve degrees roll/pitch accuracy, this is 1.25 pixels. On 100m altitude flights, the pixel size is 2.7cm, with post processed GPS data you can achieve down to 2.5cm absolute accuracy. So the georeferencing errors are on pixel (cm) levels. 23

24 Gremsy H16 gimbal perfectly suited for Mjolnir: Gimbal and Mjolnir payload powered by same battery Encoder with resolution up to Ultra accurate IMU sensor with temperature compensation Simple 5 minutes setup & balance with Auto Tuning Feature gmotion Controller based on a 32 bit ARM high speed microprocessor providing super fast response and accurate calculation 24

25 Gimbal vs No gimbal on octocopters 25

26 Standard Link Option: TCP/IP modems Direct control of HYSPEX AIR on Mjolnir mission computer via Remote Desktop Realtime video over remote desktop, or separate TCP/IP streaming. HySpex Mjolnir TCP/IP 12V 7-30V Nano DLL Digital Data Link Master Nano DLL Digital Data Link Slave TCP/IP Software Software 26

27 HySpex AIR Acquisition software Real Time video feed Status messages Real Time waterfall preview of default RGB bands from Mjolnir. INS info Exposure control Special UAV commands Temperature, Link and battery monitor 27

28 RT-GEO: Real time processing software for UAV applications Real time georeferencing Real time visualization of image Real time image enhancement Real time multiple types of Image processing Visualization of different output as a layer RTGEO was tested successfully already in 2013 Currently implementing custom algorithms to make real-time classified maps, real-time target detection, real-time indices maps etc. In the RT-GEO software different types of index maps and classified maps will be streamed to groundstation via TCP/IP interface, thus making the maps available when you are flying an area. 28

29 HySpex Mjolnir V-1240 Real time georeferencing and image processing as distributed system Camera Computer Ground Computer 29

30 RT-GEO DEMO : Georeferencing, CRX, NDVI 30

31 Mjolnir systems for field applications All Mjolnir systems are easily deployable for field work by mounting it on a tripod with a rotation stage. The systems deliver optimal optical performance for working distances from 20m to infinity. The compact and self-contained design, low weight and low power consumption make it possible for just one person to carry and operate it in even remote locations. Scan speed fully synchronized with camera frame rate Easy wireless operation from tablet or laptop The system is ideal for field work related to applications like geology, vegetation, cultural heritage and many more Mjolnir S-620 on tripod 31

32 Conclusion Mjolnir systems provide state of the art scientific grade hyperspectral imaging system designed specifically for UAVs. Based on NEO s more than 20 years experience in hyperspectral imaging High quality components and rigorous testing ensures optimal performance Demo data is available for evaluation (on ftp) Questions/comments? hyspex@neo.no or lukas@neo.no 32

33 References Resampling in hyperspectral cameras as an alternative to correcting keystone in hardware, with focus on benefits for the optical design and data quality ; A. Fridman, G. Høye, T. Løke; Optical Engineering 53(5), (May 2014) Method for quantifying image quality in push-broom hyperspectral cameras ; G. Høye, T. Løke, A. Fridman; Optical Engineering, 54(5), (2015). doi: /1.oe