FIELD SPECTROMETER QUICK-START GUIDE FOR FIELD DATA COLLECTION (LAST UPDATED 23MAR2011) The ASD Inc FieldSpec Max spectrometer is a precision instrument designed for obtaining high spectral resolution reflectance measurements in the visible and shortwave infrared wavelengths (350 nm to 2500 nm) from sample locations on the ground. The following information and procedures are meant to serve as a practical guide for setting up and calibration of the spectrometer for acquiring reflectance measurements in the field. Instructions must be carefully followed in order to obtain accurate reflectance measurements with the spectrometer. NOTE: Only general data collection instructions are outlined here. Field data collection methods and instrument accessory devices may vary depending on the research objectives and specific applications. Don t worry if you are not up to speed on all aspects of using the various spectrometer devices. You also have the opportunity to learn about these accessory devices in the ENV499/599 course and workshops. This guide will give you the basic measurement steps that can be readily adapted to many different field applications. Checklist of Standard Spectrometer Field Equipment NOTE: Each instrument requires a power source and cable attachments to the main unit. Most cables are not permanently attached so be sure to have all of the appropriate gear and that all batteries are FULLY CHARGED for any given piece of equipment to have a successful field experience. Instrument Required power source, cables, peripherals Main spectrometer unit with attached -Main unit battery fiberoptic cable -back-up batteries (2) -battery cable connectors (2) -Large black pelican case (transport unit to/from field) -Ergonomic backpack (in field use) Control laptop (contains main battery) Spare battery Plastic work platform and carrying harness GPS unit USB cable to main unit Pistol grip Foreoptics (1 or 8 ) White reference disk Use: Instrument calibration Shortcut Quick Reference to RS 3 software Use: Guide for spectrometer measurement software Optional field measurement accessories Plant probe/leaf clip Plant probe cable to main unit Pistol grip pole Smart detector Tripod 1
Other Recommended Standard Field Equipment Clip board or field notebook for recording field information Vest or other pocketed clothing for ease of carrying accessory devices and equipment when operating the spectrometer (e.g., forestry cruisers vest) Principle Software for Field Applications on Control Laptop RS 3 - software used for taking a spectral measurement ViewSpec Pro for viewing, checking and manipulating spectral data collected Before Getting Started Before heading to the field, check to make sure you have all equipment needed for measurement and calibration, and that all batteries are fully charged. This usually requires preparing for the field a day or two in advance. Find a good field assistant. One individual can assemble all equipment and take a measurement in the field. However the pelican box is heavy to lift into a vehicle, and there are many aspects of setting up and operating the equipment that can go faster with two people. Identify an efficient way to label spectrometer data files. Spectral measurements have a file extension of. asd files in the RS 3 directory. The RS 3 directory can fill up with many files during the course of a field sampling period, so it is important to keep track of them with a clear file naming convention. 2
Setting up Spectrometer Equipment Lab of Landscape Ecology and Conservation Biology 1. Carefully remove the backpack and spectrometer from the pelican box and lay it flat on top of the backpack straps in a stable location. 2. Turn the spectrometer on as soon as you are ready to begin working in an area. It is best to give the spectrometer 10 minutes to warm up. It is also good practice to switch the spectrometer on first, and then assemble the rest of your equipment. Keep in mind that the spectrometer and laptop battery life is about 4 hours, so you will want to control your power use if working with the spectrometer for long periods of time. 3. Attach the control laptop to the plastic work platform and turn it on. Leave the laptop sound on and volume up, so you can listen for various connections and warnings as they occur throughout the measurement process. 4. Carefully uncoil the fiberoptic cable from its mesh pocket on the back of the spectrometer. BE CAREFUL not to crimp or bend the cable in any way. At this point, you can put on the spectrometer backpack, and position the plastic work platform and laptop in front of you. It is much easier to set up the backpack and equipment with the help of a field assistant. 5. Attach the cable to the pistol grip, foreoptic, or other desired measurement device. 6. Once the laptop is fully booted, start the RS 3 software from the icon on the desktop. Choose the High Contrast version of RS 3 for outdoor applications. 7. The Bluetooth connection between the spectrometer in the control laptop should be shown in the very lower right corner of the main RS 3 window. Often, a message will appear indicating that the two systems are connected. 8. The GPS should be connected once the spectrometer and laptop are communicating. a. Do NOT turn the GPS on. The GPS will turn on when you when you insert the USB cable b. A message will appear Use as mass storage device? Select NO on the GPS touch screen, and you are done. c. You will see latitude and longitude coordinates at the lower left window of the RS 3 software when the GPS is properly connected and you have sufficient satellites. d. You may have to manually start the GPS by opening the Start menu and then by double clicking the Spanner software. This process usually works, but if not, disconnect the GPS USB cable and start again. You should now be ready to begin spectrometer calibration and collect your data! 3
Taking a Spectrometer Measurement Spectrometer measurement protocols will vary depending on what your study objectives are. Below are instructions to be used as a general guide and gives an example of how the spectrometer equipment typically appears when set up in the field (Figure 1). 1. To begin, you should be looking at the RS 3 software s main window with the spectrometer and GPS turned on and running. 2. You should first set up the file naming convention, sampling interval and number of files to be collected from the Control and Spectrum Save menus. There is also a space for notes that will automatically be added to the data file header you are creating with each measurement. Remember that selecting OK does NOT save a reflectance measurements, it is only saving the file configuration that you ve selected in Spectrum Save. 3. Make sure that the pull-down menu at the top of the RS 3 window has the proper foreoptic selected (i.e., bare cable, 1, 8 ). 4. Use the left side of the RS 3 window and set of status bars to monitor all spectrometer calibration and measurement processes. 5. You should now calibrate the spectrometer for the sun illumination conditions at the Figure 1. Typical configuration using the spectrometer in the back-pack carrier. sample site by selecting the Optimize button in RS 3 while pointing the bare cable end or foreoptic at the white reference disk. Without casting a shadow on the white reference select the Opt button, or use the proper shortcut key that is sometimes faster. Watch the Optimize status bar to make sure you ve completed this step. Once you ve optimized, it is not necessary to do this as often as taking a white reference. However, if a saturation warning occurs, we recommend Optimizing the system again to accommodate changing illumination conditions. 6. Take a white reference by selecting the WR button from the upper left set of buttons. This process will automatically take a dark current measurement, which you can hear as the shutter closes inside the spectrometer. Watch the status bar as the dark current and then white reference is taken. If you hold the white reference disk steady in place after calibration, you should see a spectral reflectance at or close to 1 across the full range of spectral values in the graph window. 7. You should take a white reference fairly often, particularly in a situation where sunlight conditions are constantly changing. 8. You are now ready to take a measurement. Point the pistol grip and foreoptic at your target and press the spacebar to begin measuring. Monitor the status bar to assure the measurement process runs to completion and that all files have been collected. Your file(s) is created and saved once the status bar shows that the measurement process has completed. 4
9. Note that you can configure the spectrometer to automatically save multiple files and average spectral values over a given time period within the Spectrum Save menu. 10. Make sure you are up-dating file names as you collect spectral measurements from different samples or locations. File names should be changed with each new measurement by returning to the Control and Spectrum Save menus. 11. Good data and file management starts with intuitive naming conventions that are imperative for properly analyzing your data once all field measurements are completed. For example, file names linked to a particular plot naming convention, plant species abbreviation, substrate type, geologic material etc. are a good means of identifying specific files to analyzed or compared later. Another means to keep track of the files you are creating is to have the ViewSpec Pro software open. This will directly link you to the place where the.asd files are saved so that you can view and manage files as they are collected. Field notes about your measurements and file naming convention will also be a help. Adding brief notes to the.asd file in Spectrum Save about the foreoptic used or other data collection procedures is also a good practice. 5
Important Support Links ISL Principal Investigator, Dr. Steven Sesnie, is the main contact for questions regarding the spectrometer, troubleshooting and applications. The ASD Inc. support team and links listed below are also good sources of information for learning about and troubleshooting measurement issues with the spectrometer. We also have the ASD System Documentation and a Remote Sensing Training Guide available at the located in Suite 220 of the Applied Research and Development Building (#56). Please contact Steven Sesnie or Jill Rundall to access ISL resources. Steven E. Sesnie Steven.Sesnie@nau.edu 928-523-7889 http://www.cefns.nau.edu/academic/cse/lab/spectrometer/index.html Main ASD Inc. page: http://www.asdi.com/ Technical Support: http://www.asdi.com/tech-support To contact ASD directly by phone call +1 (303) 444-6522 x144. 6