1. FIGIFIGO: An Advanced Portable System for Spectropolarimetry
Teemu Hakala, Maria Gritsevich, Jouni Peltoniemi and Juha Suomalainen

2. FIGIFIGO Finnish Geodetic Institute Field Goniospectrometer
A device for measuring directional properties of reflectance, Bidirectional Reflectance Factor (BRF)
Design focused on field operation, but can also be used in laboratory

3. Operation Main parts Target illuminated by Sun
Measurement arm
Goniometer body
Target illuminated by Sun
Light zenith and azimuth
Measurement arm turns from side to side (view zenith)
Goniometer body turned around the target (view azimuth)

4. Measurement
Before each target measurement a reference panel (Spectralon) is measured
The Spectralon and the target are also measured with direct illumination shadowed
The target is measured with several (~6) view azimuth angles
Total measurement time about minutes

5. Spectrometer ASD Field Spec Pro FR 350-2500 nm spectral range
3 nm
10 nm
3 meter optical fiber

6. Features (1) Measurement arm moved by a single motor
Arm angle (view zenith) measured with an electronic inclinometer
View azimuth relative to Sun measured with a fisheye camera mounted to the goniometer body
GPS position and time used to determine the light azimuth and zenith angles
Level of incident irradiance measured with a broadband (~ nm) pyranometer placed on a tripod
Used during post processing to compensate for minor changes in illumination

7. Features (2) Powered by 1-2 lead acid batteries
Several hours of measurement time
Weight ~30-40 kg depending on how many batteries
Can be carried by two people for short distances, or easily moved over snow
Position of the measurement spot can be adjusted by a motorized mirror
Used to compensate for the height displacement between arm motor axle and the sample surface

8. Optics Possible to use a custom set of polarizing optics
Linear polarizing Glan Thompson polarizer
Usually measurement with four polarizer angles: 0°, 90°, 45° and 135°
Measurement arm does four passes for each azimuth angle, one for each polarization

9. Laboratory setup FIGIFIGO can be used in laborotory
Light source: 1000 W quarz tungsten halogen with stabilized power source
Rotating ring used for more presice azimuth rotation of FIGIFIGO
Light is collimated with an off axis parabolic mirror
A flat mirror for light zenith angle adjustment

10. Software Custom LabView measurement software
Handles the measurement sequence, instrument communication, raw data storage
Matlab post processing software

11. Thank you
Suomalainen, J.; Hakala, T.; Peltoniemi, J.; Puttonen, E. Polarised Multiangular Reflectance Measurements Using the Finnish Geodetic Institute Field Goniospectrometer. Sensors 2009, 9,