SOC 710 Camera --System Design and Signal Test Jin Wu

OUTLINE *System Design --Enclosure System --Remotely Control System * Signal Test --Integrating Time + (Light, Wind) --Background Effect --BRDF Effect --Leaf Species/Layer Effect --Ambient Temperature Effect

Enclosure System The whole enclosure system include (a) housing, (b) temperature control system, (c) thermal regulation system; (d) camera viewing system, and (e) enclosure rotating system (a) housing Housing was made up of Seahorses Case SE-720, with inside dimensions as 18.29" x 13.19" x 6.62“. The cost for the case of this kind is around $48. To put it into the tower, we will choose a yellow case in future. (b) temperature control system Temperature control system is made up of Peltier Cooling Assmbly ($29.95), Power Supply ($44.95), and DC Fan ($3.95).

Enclosure System (c) thermal regulation system: including SSR PID temperature controller and cable Combined with both (b) and (c), we hope to regulate the temperature at a constant value. (d) camera viewing system A hole will be carved in the place marked in green. Joost and Steve are to find certain window glass materials to make it progress.

Enclosure System (e) Enclosure rotating system As field of view of this camera is 10 degree, we came up with an idea to design a rotating system for the whole camera settings. The weight of the whole setting (15~ 20 lbs) and how to precisely position the camera after rotating will be two main issues for our design. Any suggestion will be welcome! The rotating systems till now have got several good suggestion from Joost. Joost suggested three options ($500-$600 for rotating system): Another option from Leif, who is from Surface Optics Corporation, is to buy another lens 17mm lens with field of view as 20 degree ($1132): 69 If we want to install this lens, we should send our camera back to SOC Inc. to do spectral calibration first. Once a new lens was calibrated, we can also use it for field observation.

Remotely Control System Basic strategy in B2 (also works in Tapajos):  to place the laptop in the lab on the ground, while to install the whole enclosure system (including camera) in the top of B2 tropical forest (or eddy covariance tower in Tapajos), and the connection between laptop and camera was operated by powered USB extender (of capacity of 100 meters) The powered USB extender we are to test is “ High-Speed USB 2.0 Extender Kit - Single Port ” ($349) It will arrive at Tucson 11/14/2011. So I will report this result soon. The other component of this remotely control system is based on the software designed by SOC company, by which we can remotely control the camera to take image by setting the time step for camera. (Has been tested)

Signal Test Currently, I have done several measurements of SOC 710 camera including the following components: (1)to test how light intensity and integrating time combined affect camera image (a) low light level inside B2 tropical forests (b) high light level in the open area outside B2 facility (2 pm, cloudless) (c) medium light level in the open area outside B2 facility (3:30 -4:30 pm, cloudless) (d) medium light level in the open area outside B2 facility (2-3 pm, cloudiness) (2) to test how wind and integrating time combined affect camera image (3) to test how background might affect camera image (a) dark background; (b) grey background ~20% reflectance for all wavelength; (c) white background from print paper (4) to test leaf layers and leaf species effect (5) to compare camera based measurements and that of ASD field Spec

Signal Test Currently, I still need to improve several measurements of SOC 710 camera including the following components: (1)to test what is the BRDF effect of the camera (a) nadir view and oblique view (b) the same view angle but varies in semihemispheric space (I have done several measurements in the open area; but I still think it will be good if we can do it in the lab of control environment) (2) to test the temperature effect in the camera signal (a) I still haven’t come through any good idea to test this (b) Scott suggest to have a data recorder to keep a record of the enclosure temperature, by which we can then test the camera’s sensitivity to temperature. I will exchange the test of this part with Natalia in the weeks following to make sure if I am on the right track.

Comments or Suggestions? (1)About rotating system, or the lens, or others? (2)About better signal tests? (3)Others?