UAS Phenotyping and Aerial Image Acquisition Procedures
From Poland Lab Wiki
Welcome to the Poland Lab UAS Phenotyping Wiki page !
- 1 Data-processing Pipeline Overview
- 2 Field-setup Guide
- 3 Flight Checklists
- 4 How-to Guide
- 5 Ground Truth and Agronomic Notes (Optional)
- 6 References and other relevant links
Data-processing Pipeline Overview
Ground Control Points
- ❏ Metal sheets screwed on top of the iron rods (Figure 2b)
- Materials required:
- 1. 7mm thick lightweight plywood.
- 2. Flat black and white water based color (1 liter each).
- 3. Wood primer (1/2 liter)
- 4. Paint mixing trays (8 units).
- 5. Brush rollers (8 units)
- 6. 100 ml liquid syringes with 10ml markings (2 units)
- 7. 5-7mm metal hinges with 2-3 holes (4 units)
- 8. Painters tape
- Materials required:
Pre-Flight Guide – Before Leaving For Field
UAS Accessory List
- ❏ Transmitter (Figure 3a)
- ❏ Radio with USB cable
- ❏ UAV batteries and battery chargers
- ❏ Extra set of propellers/wings
- ❏ Camera(s) with fully charged batteries
- ❏ Multimeter (optional)
- ❏ Toolkit (wrench set, propeller hex-key, camera mount screws and screwdriver etc.) (Figure 3b)
- ❏ Camera gimbal
- ❏ SD cards with CHDK installed
- ❏ Color calibration panel
- ❏ Ground Control Points installed in field
Things to check before leaving lab
- ❏ An updated version of Mission Planner Software is installed on the field laptop.
- ❏ Has the field map been cached in the Mission Planner program? Details on map caching procedure are discussed below in section 3.3 (Note: This step is required only once per phenotyping field.)
- ❏ Does RC Transmitter have enough voltage? FrSky transmitter should have ≥ 9.4V charge.
- ❏ Are UAV batteries charged? 3-cell batteries should charge up to 12.6V.
- ❏ Is the laptop charged? Do you need/have a laptop charger?
- ❏ Ensure that you are familiar with the laws and regulations related to flying UAVs in your country/area. General laws in the United States require 400 feet maximum height and within line-of-sight flying.
- ❏ Make sure you have watched all the UAV manufacturer recommended tutorials before your first flight.
- ❏ When first flying your IRIS+, make sure to fly it away from populated areas and only in open space.
- ❏ Before the first flight, make sure to perform a compass calibration otherwise this could lead to a bad behavior in GPS enabled modes. You can perform the compass calibration through APM or Mission Planner programs following this youtube video.
At-field- Pre-Flight Checklist
Note: These settings are based on Canon PowerShot S100/S95/S110 Point & Shoot cameras.
- → General recommendations for aerial imagery:
- ❏ Keep the camera focal length fixed throughout the mission.
- ❏ Shoot in RAW since the RAW format retains maximum scene details and provides greater flexibility during post-processing.
- ❏ Use faster shutter speeds to avoid blur due to vehicle speed and vibration.
- ❏ Use gimbal to get maximum nadir shots of the scene and to avoid image blurring.
- ❏ Set the Manual Focus (MF) setting to infinity for >5 meter altitude flights.
- → Choose one of the following camera shooting modes:
- 1. Shutter Priority (Tv) mode:
- ❏ Optional: Ev (exposure): 0, -1/3 or -2/3 (again adjust based on ambient light conditions)
- 2. Manual (M) mode:
- ❏ ISO: ~80-250 (adjust based on ambient light). Hint: Higher ISO, brighter image but higher noise.
- ❏ Ev (exposure): -1/3 or -2/3. Again, adjust based on ambient light conditions.
- → Under MENU option, change the default settings to:
- ❏ GPS ON
- ❏ MF-point ZOOM OFF
- ❏ Safety MF OFF
- ❏ Wind Filter OFF
- ❏ Image format: Camera raw (CR2)
UAS In-field Pre-flight Checklist
- ❏ Place the UAV on a flat surface, plug-in the battery and close the lid. Note: Avoid any disturbance to the UAV during initial few seconds as the UAV performs automatic sensor-calibrations.
- ❏ Lock the SD card and insert it in camera.
- ❏ Switch-on the camera by pressing the preview button.Half-press the shutter to let the lens out.
- ❏ Set the camera parameters by following the instructions given in section 3.2.1.
- ❏ Attach the camera to the gimbal mount and plug-in the wire.
- ❏ Load and run CHDK script by half-pressing the camera shutter button.
- ❏ Open mission planner on field laptop and connect mission planner to UAV Autopilot using telemetry radio link. Use a correct COM PORT Number and 57600 Baud rate from the drop down menu on top right corner of mission planner software. Then hit connect.
- ❏ Check flight parameters (see parameter section below for detailed parameter list)
- ❏ Load proper mission waypoint file and write the waypoints into the Autopilot through radio link. Note: You can read back the WP from UAV to double check the correct WayPoints are written to the UAV.
- ❏ Make sure the GPS signal is good (3D fix: number of satellites > 7 and hdop < 2) and there is no error message flashing on the mission planner main window.
- ❏ Check if the camera trigger is working properly by walking the UAV. Note: Make sure the UAV safety light is flashing to avoid accidental arming.
- ❏ Check battery voltage.
- ❏ Turn the radio controller (RC) transmitter on.
- ❏ Check to make sure the RC switch positions are set to:
- ❏ Stabilized Mode [ON], RTL [OFF], Throttle [All the way Down].
- ❏ Depending upon how the other RC switches are mapped, make sure the switches are set to a mode that is safe for take-off.
- ❏ Check the trims are zero (offsets to stick positions that can be set with small slide switches).
- ❏ Make sure no one is close to UAV and survey area.
In Field After Arming Checklist
- Arm the UAV in Stabilized mode (STB) and take off in AUTO mode.
- After take off, adjust the yaw position with controller stick if necessary.
- Keep a close eye on UAV during first 3-4 WPs to make sure mission plan is being followed correctly.
- At the end of the mission, during landing (when UAV is ~5-6 inches above ground), swiftly flip the flight mode switch to stabilized mode while making sure throttle is all the way down. Note: The landing will gets better with regular practice.
- Try this trick for bigger experimental fields that require changing batteries on regular intervals:
- As soon as the battery hits ~10.80-10.85V mark and UAV is at the most closest waypoint to the take-off position, hit the RTL (return to launch) button on the controller.
- Make a note of the last WP the UAV was about to head to. Let the UAV land safely on the launch pad and un-arm it.
- Disconnect the mission planner program.
- Press safety button on UAV.
- Stop the CHDK camera script by half-pressing the shutter button.
- Replace the battery. Connect the Mission Planner program.
- UAV takes off again in AUTO but this time as soon as the UAV hits Do_Change_Speed Waypoint, on Mission Planner, go to ‘ACTIONS’ menu and choose the last UAV WP from step 2, and hit SET WP. Now the UAV will jump to the selected WP. (Note: Always let the UAV hit Do_Change_Speed and Do_Set_Cam_Trigger_Distance WP before pushing the SET button.)
CHDK Installation on SD Card
- Low-level format the SD card in the camera.
- Check to find out the correct camera firmware version using Acid App on Windows 8 and onwards.
- Download and run EOScard utility program to make the SD card bootable (the link is in the references section).
- Download and unzip an appropriate CHDK version for your camera firmware.
- Copy the unzipped CHDK files into the root (main) folder of your SD card. The Other relevant scripts such as 'NEG_APM.bas' should be copied to the scripts folder inside the CHDK. NEG_APM.bas script can be accessed here.
- Lock your SD card and put it back into the camera.
- Fire-up the camera using playback button and go to CHDK Settings → Remote Parameters and check Enable Remote option. Remote parameters are enabled to facilitate the camera trigger using the UAS autopilot.
- Select an appropriate script for your UAS operation.
Here is the official instruction page for CHDK installation.